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Background: Our understanding of the relationship between sagittal alignment and mechanical complications is evolving. In normal spines, the L1-pelvic angle (L1PA) accounts for the magnitude and distribution of lordosis and is strongly associated with pelvic incidence (PI), and the T4-pelvic angle (T4PA) is within 4° of the L1PA. We aimed to examine the clinical implications of realignment to a normal L1PA and T4-L1PA mismatch., Methods: A prospective multicenter adult spinal deformity registry was queried for patients who underwent fixation from the T1-T5 region to the sacrum and had 2-year radiographic follow-up. Normal sagittal alignment was defined as previously described for normal spines: L1PA = PI × 0.5 - 21°, and T4-L1PA mismatch = 0°. Mechanical failure was defined as severe proximal junctional kyphosis (PJK), displaced rod fracture, or reoperation for junctional failure, pseudarthrosis, or rod fracture within 2 years. Multivariable nonlinear logistic regression was used to define target ranges for L1PA and T4-L1PA mismatch that minimized the risk of mechanical failure. The relationship between changes in T4PA and changes in global sagittal alignment according to the C2-pelvic angle (C2PA) was determined using linear regression. Lastly, multivariable regression was used to assess associations between initial postoperative C2PA and patient-reported outcomes at 1 year, adjusting for preoperative scores and age., Results: The median age of the 247 included patients was 64 years (interquartile range, 57 to 69 years), and 202 (82%) were female. Deviation from a normal L1PA or T4-L1PA mismatch in either direction was associated with a significantly higher risk of mechanical failure, independent of age. Risk was minimized with an L1PA of PI × 0.5 - (19° ± 2°) and T4-L1PA mismatch between -3° and +1°. Changes in T4PA and in C2PA at the time of final follow-up were strongly associated (r 2 = 0.96). Higher postoperative C2PA was independently associated with more disability, more pain, and worse self-image at 1 year., Conclusions: We defined sagittal alignment targets using L1PA (relative to PI) and the T4-L1PA mismatch, which are both directly modifiable during surgery. In patients undergoing long fusion to the sacrum, realignment based on these targets may lead to fewer mechanical failures., Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The International Spine Study Group (ISSG) is funded through research grants from NuVasive, SI-Bone, DePuy Synthes Spine, K2M, Stryker, Biomet, AlloSource, and Orthofix, and individual donations. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/I191 )., (Copyright © 2024 by The Journal of Bone and Joint Surgery, Incorporated.)

Purpose: Understanding the mechanism and extent of preoperative deformity in revision procedures may provide data to prevent future failures in lumbar spinal fusion patients., Methods: ASD patients without prior spine surgery (PRIMARY) and with prior short (SHORT) and long (LONG) fusions were included. SHORT patients were stratified into modes of failure: implant, junctional, malalignment, and neurologic. Baseline demographics, spinopelvic alignment, offset from alignment targets, and patient-reported outcome measures (PROMs) were compared across PRIMARY and SHORT cohorts. Segmental lordosis analyses, assessing under-, match, or over-correction to segmental and global lordosis targets, were performed by SRS-Schwab coronal curve type and construct length., Results: Among 785 patients, 430 (55%) were PRIMARY and 355 (45%) were revisions. Revision procedures included 181 (23%) LONG and 174 (22%) SHORT corrections. SHORT modes of failure included 27% implant, 40% junctional, 73% malalignment, and/or 28% neurologic. SHORT patients were older, frailer, and had worse baseline deformity (PT, PI-LL, SVA) and PROMs (NRS, ODI, VR-12, SRS-22) compared to primary patients (p < 0.001). Segmental lordosis analysis identified 93%, 88%, and 62% undercorrected patients at LL, L1-L4, and L4-S1, respectively. SHORT patients more often underwent 3-column osteotomies (30% vs. 12%, p < 0.001) and had higher ISSG Surgical Invasiveness Score (87.8 vs. 78.3, p = 0.006)., Conclusions: Nearly half of adult spinal deformity surgeries were revision fusions. Revision short fusions were associated with sagittal malalignment, often due to undercorrection of segmental lordosis goals, and frequently required more invasive procedures. Further initiatives to optimize alignment in lumbar fusions are needed to avoid costly and invasive deformity corrections., Level of Evidence: IV: Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding., Competing Interests: Declarations. Conflicts of interest: The authors declare that they have no conflicts of interest related to this paper., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Prior studies demonstrate that muscle and bone health are integrally related, and both independently impact orthopedic surgery outcomes. However, relationships between bone density, in vivo microarchitecture, and muscle area have not been previously investigated in orthopedic surgery patients. This study assessed associations between psoas cross sectional area (CSA), bone mineral density (BMD), and microstructure in a cohort undergoing spine fusion. Pre-operatively, bilateral psoas CSA was measured on axial lumbar spine CT in the L3-L4 disc space. To adjust for body size, Psoas Muscle Index (PMI) was calculated (CSA divided by the square of patient height). High resolution peripheral quantitative CT (HR-pQCT, XtremeCT2) assessed volumetric BMD (vBMD), cortical (Ct) and trabecular (Tb) microarchitecture at the distal radius and tibia. Areal BMD (aBMD) was measured by DXA at the lumbar spine (LS), total hip (TH), femoral neck (FN), and the 1/3 radius (1/3R). Pearson correlations related psoas CSA and bone imaging parameters before and after correcting for height and weight. Among 88 patients included, mean age was 63 ± 12 years, BMI was 28 ± 7 kg/m 2 , 47 (53 %) were female. Larger psoas CSA was associated with higher vBMD, greater Ct thickness and better Tb microarchitecture (higher Tb number and lower Tb separation) at the tibia and radius. Larger psoas CSA was also associated with greater aBMD at TH and FN bilaterally and 1/3R (r 0.33 to 0.61; p < 0.002 for all comparisons). Psoas CSA was not associated with aBMD at the LS. Similar results were observed when relating PMI, and adjusting for age, height and weight to HR-pQCT and DXA measurements. Investigation of subgroups by sex demonstrated that relationships were similar magnitude among women but not the men. Patients who underwent primary compared to revision spine surgery had similar associations. Our results demonstrate a link between psoas muscle size and peripheral bone microarchitecture among patients undergoing posterior lumbar spinal fusion. Given the importance of both muscle and skeletal integrity to the success of spine surgery, further study regarding the associations between measurements of psoas muscle, bone microarchitecture, and surgical outcomes is warranted., Competing Interests: Declaration of competing interest Mr. Raphael, Ms. D'Erasmo, Dr. Dash, Ms. Billings, and Dr. Song declare no competing financial interests. Dr. Kim reports relationships with Acuity Surgical (equity or stocks), Aspen Medical Products Inc. (board membership), HS2, LLC (equity or stocks), International Spine Study Group (funding grants), K2 Medical Systems Limited (equity or stocks and speaking and lecture fees), NuVasive Inc. (board membership), SPINE STUD (equity or stocks), Vivex Biologics, Inc. (board membership), and with Zimmer Biomet (consulting or advisory fees and equity or stocks). Dr. Cunningham reports relationships with Radius Health Inc. (funding grants) and Sustain Surgical (equity or stocks). Dr. Nieves reports relationships with Radius Health Inc. (funding grants). Dr. Stein reports relationships with Radius Health Inc. (funding grants) and Novartis (funding grants). Dr. Iyer reports relationships with HS2,LLC (ownership interest and editorial board), HSS ASC Development network, LLC (ownership interest), Joint Effort Administrative Services Organization, LLC (ownership interest), Innovasis (consultant), and Intrinsic Therapeutics (consultant). Dr. Qureshi reports relationships with AMOM opportunities (Honoraria), Globus Medical, Inc. (speakers' bureau, consultant, and royalties), HS2, LLC (ownership interest), HSS ASC Development Network, LLC (ownership interest), Stryker K2M (consultant, royalties and designer), Tissue Differentiation Intelligence (ownership interest), See All AI (ownership interest, scientific advisory board), and Viseon, Inc. (research support, consultant). Dr. Breighner reports a relationship with Stryker (consulting). FUNDING: This research was supported by R01AR081574 NIH/NIAMS and the Anna-Maria and Stephen Kellen Foundation., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Study Design: Retrospective review of prospectively collected data., Objective: To identify the risk factors associated with failure to respond to erector spinae plane (ESP) block following minimally invasive transforaminal lumbar interbody fusion (MI-TLIF)., Summary of Background Data: ESP block is an emerging opioid-sparing regional anesthetic that has been shown to reduce immediate postoperative pain and opioid demand following MI-TLIF-however, not all patients who receive ESP blocks perioperatively experience a reduction in immediate postoperative pain., Methods: This was a retrospective review of consecutive patients undergoing one-level MI-TLIF who received ESP blocks by a single anesthesiologist perioperatively at a single institution. ESP blocks were administered in the OR following induction. Failure to respond to ESP block was defined as patients with a first numerical rating scale (NRS) score postsurgery of >5.7 (mean immediate postoperative NRS score of control cohort undergoing MI TLIF without ESP block). Multivariable logistic regressions were performed to identify predictors for failure to respond to ESP block., Results: A total of 134 patients were included (mean age 60.6 yr, 43.3% females). The median and interquartile range (IQR) first pain score postsurgery was 2.5 (0.0-7.5). Forty-nine (36.6%) patients failed to respond to ESP block. In the multivariable regression analysis, several independent predictors for failure to respond to ESP block following MI TLIF were identified: female sex (OR 2.33, 95% CI 1.04-5.98, P =0.040), preoperative opioid use (OR 2.75, 95% CI 1.03-7.30, P =0.043), anxiety requiring medication (OR 3.83, 95% CI 1.27-11.49, P =0.017), and hyperlipidemia (OR 3.15, 95% CI 1.31-7.55, P =0.010)., Conclusions: Our study identified several predictors for failure to respond to ESP block following MI TLIF, including female gender, preoperative opioid pain medication use, anxiety, and hyperlipidemia. These findings may help inform the approach to counseling patients on perioperative outcomes and pain expectations following MI-TLIF with ESP block., Level of Evidence: 3., Competing Interests: S.I.: Globus Medical: Paid presenter or speaker; Stryker: Paid presenter or speaker; Vertebral Columns/International Society for the Advancement of Spine Surgery (ISASS): Editorial or governing board; HS2, LLC: Ownership/Equity/Investment; Innovasis: Research Support (either personally or through institution). S.Q.: aMOpportunities: Other financial or material support; Annals of Translational Medicine: Editorial or governing board; Association of Bone and Joint Surgeons: Board or committee member; Cervical Spine Research Society: Board or committee member; Contemporary Spine Surgery: Editorial or governing board; Globus Medical: IP royalties; Paid consultant; Paid presenter or speaker; Hospital Special Surgery Journal: Editorial or governing board; HS2, LLC: Stock or stock Options; International Society for the Advancement of Spine Surgery (ISASS) - Program Committee member: Board or committee member; Lifelink.com: Other financial or material support; Lumbar Spine Research Society: Board or committee member; Minimally Invasive Spine Study Group: Board or committee member; North American Spine Society: Board or committee member; Simplify Medical, Inc.: Other financial or material support; Society of Minimally Invasive Spine Surgery (SMISS) - Program Committee member: Board or committee member; Spinal Simplicity: Other financial or material support; SpineGuard, Inc.: Paid consultant; Stryker: IP royalties; Paid consultant; Surgalign: Paid consultant; Tissue Differentiation Intelligence: Stock or stock Options; Viseon, Inc.: Paid consultant; Research support; Clinical Spine Surgery: Editorial or governing board. AH: Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - project number 526240791. The remaining authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: To test equivalency of deep-learning 3D lumbar spine MRI with "CT-like" contrast to CT for virtual pedicle screw planning and geometric measurements in robotic-navigated spinal surgery., Methods: Between December 2021 and June 2022, 16 patients referred for spinal fusion and decompression surgery with pre-operative CT and 3D MRI were retrospectively assessed. Pedicle screws were virtually placed on lumbar (L1-L5) and sacral (S1) vertebrae by three spine surgeons, and metrics (lateral deviation, axial/sagittal angles) were collected. Vertebral body length/width (VL/VW) and pedicle height/width (PH/PW) were measured at L1-L5 by three radiologists. Analysis included equivalency testing using the 95% confidence interval (CI), a margin of ± 1 mm (± 2.08° for angles), and intra-class correlation coefficients (ICCs)., Results: Across all vertebral levels, both combined and separately, equivalency between CT and MRI was proven for all pedicle screw metrics and geometric measurements, except for VL at L1 (mean difference: - 0.64 mm; [95%CI - 1.05, - 0.24]), L2 (- 0.65 mm; [95%CI - 1.11, - 0.20]), and L4 (- 0.78 mm; [95%CI - 1.11, - 0.46]). Inter- and intra-rater ICC for screw metrics across all vertebral levels combined ranged from 0.68 to 0.91 and 0.89-0.98 for CT, and from 0.62 to 0.92 and 0.81-0.97 for MRI, respectively. Inter- and intra-rater ICC for geometric measurements ranged from 0.60 to 0.95 and 0.84-0.97 for CT, and 0.61-0.95 and 0.93-0.98 for MRI, respectively., Conclusion: Deep-learning 3D MRI facilitates equivalent virtual pedicle screw placements and geometric assessments for most lumbar vertebrae, with the exception of vertebral body length at L1, L2, and L4, compared to CT for pre-operative planning in patients considered for robotic-navigated spine surgery., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: Adult spinal deformity (ASD) patients with sagittal plane deformity (N) or structural lumbar/thoraco-lumbar (TL) curves can be treated with fusions stopping at the TL junction or extending to the upper thoracic (UT) spine. This study evaluates the impact on cost/cumulative quality-adjusted life year (QALY) in patients treated with TL vs UT fusion., Methods: ASD patients with > 4-level fusion and 2-year follow-up were included. Index and total episode-of-care costs were estimated using average itemized direct costs obtained from hospital records. Cumulative QALY gained were calculated from preoperative to 2-year postoperative change in Short Form Six-Dimension (SF-6D) scores. The TL and UT groups comprised patients with upper instrumented vertebrae (UIV) at T9-T12 and T2-T5, respectively., Results: Of 566 patients with type N or L curves, mean age was 63.2 ± 12.1 years, 72% were female and 93% Caucasians. Patients in the TL group had better sagittal vertical axis (7.3 ± 6.9 vs. 9.2 ± 8.1 cm, p = 0.01), lower surgical invasiveness (- 30; p < 0.001), and shorter OR time (- 35 min; p = 0.01). Index and total costs were 20% lower in the TL than in the UT group (p < 0.001). Cost/QALY was 65% lower (492,174.6 vs. 963,391.4), and 2-year QALY gain was 40% higher, in the TL than UT group (0.15 vs. 0.10; p = 0.02). Multivariate model showed TL fusions had lower total cost (p = 0.001) and higher QALY gain (p = 0.03) than UT fusions., Conclusion: In Schwab type N or L curves, TL fusions showed lower 2-year cost and improved QALY gain without increased reoperation rates or length of stay than UT fusions., Level of Evidence: III., (© 2024. The Author(s), under exclusive licence to Scoliosis Research Society.)

Background Context: Returning to recreational sporting activities after adult spinal deformity (ASD) correction may significantly impact the patient's perceived quality of life., Purpose: This study sought to characterize participation in sporting activities before and after ASD surgery, and to identify factors associated with impaired return to sports., Study Design: Cross-sectional survey and retrospective review of prospectively collected data., Patient Sample: Patients who underwent posterior-only thoracolumbar ASD surgery between 2016 and 2021 with ≥1 year follow-up and ≥3 levels of fusion to the pelvis were included., Outcome Measures: Preoperative and postoperative participation in sports, timing of return to these activities, and reasons for limited sports participation postoperatively were assessed., Methods: A survey was used to evaluate outcome measures. Differences in demographic, surgical, and perioperative variables between patients who reported improved, unchanged, or worsened activity tolerance were evaluated., Results: Ninety-five patients were included (mean age: 64.3±10.1 years; BMI: 27.3±6.1 kg/m 2 ; median levels fused: 7). The survey was completed at an average of 43.5±15.9 months after surgery. Sixty-eight (72%) patients participated in sports preoperatively. The most common sports were swimming (n=33, 34.7%), yoga (n=23, 24.2%), weightlifting (n=20, 21.1%), elliptical (n=19, 20.0%), and golf (n=11, 11.6%). Fifty-seven (83.8%) returned to at least one sport postoperatively, most commonly 6-12 months after surgery (45%). Elliptical had the highest rate of equal or improved participation (53%). Patients generally returned below their preoperative level to all other sports. Reasons for reduced sporting activities included physical limitation (51.4%), fear (20.0%), pain (17.1%), and surgeon advice (8.6%). There were no differences in the demographic, surgical, or perioperative characteristics between those who returned to sports at the same or better level compared with those who returned at a lower level., Conclusions: About 84% of patients successfully resumed sporting activities after undergoing fusion to the sacrum/pelvis for ASD. However, this return is typically at a lower level of participation than their preoperative participation, particularly in higher demand sports. Understanding trends in sporting activity may be valuable for counseling patients and setting expectations., Competing Interests: Declaration of competing interest One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Purpose: To compare the outcomes of decompression alone and fusion for L4-5 DLS in different age cohorts (< 70 years, ≥ 70 years)., Methods: This retrospective cohort study included patients who underwent minimally invasive decompression or fusion for L4-5 DLS and had a minimum of 1-year follow-up. Outcome measures were: (1) patient-reported outcome measures (PROMs) (Oswestry Disability Index, ODI; Visual Analog Scale back and leg, VAS; 12-Item Short Form Survey Physical Component Score, SF-12 PCS), (2) minimal clinically important difference (MCID), (3) patient acceptable symptom state (PASS), (4) response on the global rating change (GRC) scale, and (5) complication rates. The decompression and fusion groups were compared for outcomes separately in the < 70-year and ≥ 70-year age cohorts., Results: 233 patients were included, out of which 52% were < 70 years. Patients < 70 years showed non-significant improvement in SF-12 PCS and significantly lower MCID achievement rates for VAS back after decompression compared to fusion. Analysis of the ≥ 70-year age cohort showed no significant differences between the decompression and fusion groups in the improvement in PROMs, MCID/PASS achievement rates, and responses on GRC. Patients ≥ 70 years undergoing fusion had significantly higher in-hospital complication rates. When analyzed irrespective of the surgery type, both < 70-year and ≥ 70-year age cohorts showed significant improvement in PROMs with no significant difference., Conclusions: Patients < 70 years undergoing decompression alone did not show significant improvement in physical function and had significantly less MCID achievement rate for back pain compared to fusion. Patients ≥ 70 years showed no difference in outcomes between decompression alone and fusion., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background Context: Robotic spine surgery, utilizing 3D imaging and robotic arms, has been shown to improve the accuracy of pedicle screw placement compared to conventional methods, although its superiority remains under debate. There are few studies evaluating the accuracy of 3D navigated versus robotic-guided screw placement across lumbar levels, addressing anatomical challenges to refine surgical strategies and patient safety., Purpose: This study aims to investigate the pedicle screw placement accuracy between 3D navigation and robotic arm-guided systems across distinct lumbar levels., Study Design: A retrospective review of a prospectively collected registry., Patient Sample: Patients undergoing fusion surgery with pedicle screw placement in the prone position, using either via 3D image navigation only or robotic arm guidance., Outcome Measure: Radiographical screw accuracy was assessed by the postoperative computed tomography (CT) according to the Gertzbein-Robbins classification, particularly focused on accuracy at different lumbar levels., Methods: Accuracy of screw placement in the 3D navigation (Nav group) and robotic arm guidance (Robo group) was compared using Chi-squared test/Fisher's exact test with effect size measured by Cramer's V, both overall and at each specific lumbosacral spinal level., Results: A total of 321 patients were included (Nav, 157; Robo, 189) and evaluated 1210 screws (Nav, 651; Robo 559). The Robo group demonstrated significantly higher overall accuracy (98.6 vs 93.9%; p<.001, V=0.25). This difference of no breach screw rate was signified the most at the L3 level (No breach screw: Robo 91.3 vs 57.8%, p<.001, V=0.35) followed by L4 (89.6 vs 64.7%, p<.001, V=0.28), and L5 (92.0 vs 74.5%, p<.001, V=0.22). However, screw accuracy at S1 was not significant between the groups (81.1 vs 72.0%, V=0.10)., Conclusion: This study highlights the enhanced accuracy of robotic arm-guided systems compared to 3D navigation for pedicle screw placement in lumbar fusion surgeries, especially at the L3, L4, and L5 levels. However, at the S1 level, both systems exhibit similar effectiveness, underscoring the importance of understanding each system's specific advantages for optimization of surgical complications., Competing Interests: Declaration of competing interest One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2024. Published by Elsevier Inc.)

Study Design: Retrospective review of prospectively collected data., Objective: To analyze temporal trends in improvement after minimally invasive transforaminal lumbar interbody fusion (MIS TLIF)., Summary of Background Data: Although several studies have shown that patients improve significantly after MIS TLIF, evidence regarding the temporal trends in improvement is still largely lacking., Methods: Patients who underwent primary single-level MIS TLIF for degenerative conditions of the lumbar spine and had a minimum of 2-year follow-up were included. Outcome measures were: 1) patient reported outcome measures (PROMs) (Oswestry Disability Index, ODI; Visual Analog Scale, VAS back and leg; 12-Item Short Form Survey Physical Component Score, SF-12 PCS); 2) global rating change (GRC); 3) minimal clinically important difference (MCID); and 4) return to activities. Timepoints analyzed were preoperative, 2 weeks, 6 weeks, 3 months, 6 months, 1 year, and 2 years. Trends across these timepoints were plotted on graphs., Results: 236 patients were included. VAS back and VAS leg were found to have statistically significant improvement compared to the previous timepoint up to 3 months after surgery. ODI and SF-12 PCS were found to have statistically significant improvement compared to the previous timepoint up to 6 months after surgery. Beyond these timepoints, there was no significant improvement in PROMs. 80% of patients reported feeling better compared to preoperative by 3 months. >50% of patients achieved MCID in all PROMs by 3 months. Most patients returned to driving, returned to work, and discontinued narcotics at an average of 21, 20, and 10 days, respectively., Conclusions: Patients are expected to improve up to 6 months after MIS TLIF. Back pain and leg pain improve up to 3 months and disability and physical function improve up to 6 months. Beyond these timepoints, the trends in improvement tend to reach a plateau. 80% of patients feel better compared to preoperative by 3 months after surgery., Competing Interests: S.A.Q.: Royalties: Stryker K2M, Globus Medical, Inc.; Globus Medical, Inc.: HS2, LLC; Private Investments: Tissue Differentiation Intelligence; Consulting: Stryker K2M, Globus Medical, Inc.; Speaking and/or Teaching Arrangements: AMOpportunities, Globus Medical, Inc.; Board of Directors: Society of Minimally Invasive Spine Surgery; Scientific Advisory Board/Other Office: International Society for the Advancement of Spine Surgery, Cervical Spine Research Society, Lumbar Spine Research Society, North American Spine Society, Association of Bone and Joint Surgeons, Simplify Medical, Inc., LifeLink.com Inc., Society of Minimally Invasive Spine Surgery, Minimally Invasive Spine Study Group, Spinal Simplicity, LLC, Contemporary Spine Surgery, Annals of Translational Medicine. Sravisht Iyer: Innovasis (Research Support), Globus Medical (Speaker’s Bureau), Healthgrades (Advisory Board Member), Stryker (Speaker’s Bureau). The remaining authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective review, single-institution cohort studies., Objective: To compare patients with earlier ( i.e. <1.5 yr) and later ( i.e . >1.5 yr) repeat lumbar surgery to patients with no repeat surgery according to clinical characteristics at index surgery., Background: Grouping patients as earlier or later repeat surgery may reveal different associations when compared with patients with no repeat surgery., Patients and Methods: Patients undergoing index surgery for diverse conditions reported preoperative demographic/clinical variables, including comorbidity and depressive symptoms. Extent ( i.e . complexity) of surgery was assigned based on a valid index that included decompression, fusion, and instrumentation. Co-existing disease at nonoperated levels was ascertained from imaging reports. Postoperative records of all medical visits up to the time of this study (12 yr) were reviewed for repeat surgery. Patients were grouped as earlier (<1.5 yr) or later surgery (≥1.5 yr) and compared with patients with no repeat surgery in separate multivariable analyses., Results: Among 1334 patients (51% men, mean age 59), 82% did not have repeat surgery, 7% had earlier and 11% had later repeat surgery. Compared with no surgery, earlier surgery was associated with more comorbidity (OR: 1.7, CI: 1.1-2.6, P =0.02), positive depression screen (OR: 1.9, CI: 1.2-2.9, P =0.006), opioid use (OR: 1.8, CI: 1.2-2.8, P =0.008), and greater extent of index surgery (OR: 1.1, CI: 1.0-1.1, P =0.0009). Compared with no surgery, later surgery was associated with preindex lumbar surgery (OR: 1.9, CI: 1.3-2.8, P =0.0005) and disease at nonoperated levels at index surgery (OR: 1.6, CI: 1.0-2.4, P =0.05). Earlier surgeries were more likely to involve only the same vertebra as index surgery (51% vs. 16%) and later surgeries were more likely to involve only other levels (5% vs. 36%, P =0.01)., Conclusions: Earlier and later repeat lumbar surgeries differed in complexity and residual disease compared with no repeat surgery. These findings have implications for patient counseling regarding short-term and long-term postoperative spine health., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective analysis of prospectively collected data., Objective: Evaluate the impact of prior cervical constructs on upper instrumented vertebrae (UIV) selection and postoperative outcomes among patients undergoing thoracolumbar deformity correction., Background: Surgical planning for adult spinal deformity (ASD) patients involves consideration of spinal alignment and existing fusion constructs., Methods: ASD patients with (ANTERIOR or POSTERIOR) and without (NONE) prior cervical fusion who underwent thoracolumbar fusion were included. Demographics, radiographic alignment, patient-reported outcome measures (PROMs), and complications were compared. Univariate and multivariate analyses were performed on POSTERIOR patients to identify parameters predictive of UIV choice and to evaluate postoperative outcomes impacted by UIV selection., Results: Among 542 patients, with 446 NONE, 72 ANTERIOR, and 24 POSTERIOR patients, mean age was 64.4 years and 432 (80%) were female. Cervical fusion patients had worse preoperative cervical and lumbosacral deformity, and PROMs ( P <0.05). In the POSTERIOR cohort, preoperative LIV was frequently below the cervicothoracic junction (54%) and uncommonly (13%) connected to the thoracolumbar UIV. Multivariate analyses revealed that higher preoperative cervical SVA (coeff=-0.22, 95% CI=-0.43 to -0.01, P =0.038) and C2SPi (coeff=-0.72, 95% CI=-1.36 to -0.07, P =0.031), and lower preoperative thoracic kyphosis (coeff=0.14, 95% CI=0.01-0.28, P =0.040) and thoracolumbar lordosis (coeff=0.22, 95% CI=0.10-0.33, P =0.001) were predictive of cranial UIV. Two-year postoperatively, cervical patients continued to have worse cervical deformity and PROMs ( P <0.05) but had comparable postoperative complications. Choice of thoracolumbar UIV below or above T6, as well as the number of unfused levels between constructs, did not affect patient outcomes., Conclusions: Among patients who underwent thoracolumbar deformity correction, prior cervical fusion was associated with more severe spinopelvic deformity and PROMs preoperatively. The choice of thoracolumbar UIV was strongly predicted by their baseline cervical and thoracolumbar alignment. Despite their poor preoperative condition, these patients still experienced significant improvements in their thoracolumbar alignment and PROMs after surgery, irrespective of UIV selection., Level of Evidence: IV., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Introduction: Surgical counseling enables shared decision making and optimal outcomes by improving patients' understanding about their pathologies, surgical options, and expected outcomes. Here, we aimed to provide practical answers to frequently asked questions (FAQs) from patients undergoing an anterior cervical diskectomy and fusion (ACDF) or cervical disk replacement (CDR) for the treatment of degenerative conditions., Methods: Patients who underwent primary one-level or two-level ACDF or CDR for the treatment of degenerative conditions with a minimum of 1-year follow-up were included. Data were used to answer 10 FAQs that were generated from author's experience of commonly asked questions in clinic before ACDF or CDR., Results: A total of 395 patients (181 ACDF, 214 CDR) were included. (1, 2, and 3) Will my neck/arm pain and physical function improve? Patients report notable improvement in all patient-reported outcome measures. (4) Is there a chance I will get worse? 13% (ACDF) and 5% (CDR) reported worsening. (5) Will I receive a significant amount of radiation? Patients on average received a 3.7 (ACDF) and 5.5 mGy (CDR) dose during. (6) How long will I stay in the hospital? Most patients get discharged on postoperative day one. (7) What is the likelihood that I will have a complication? 13% (8% minor and 5% major) experienced in-hospital complications (ACDF) and 5% (all minor) did (CDR). (8) Will I need another surgery? 2.2% (ACDF) and 2.3% (CDR) of patients required a revision surgery. (9 & 10) When will I be able to return to work/driving? Most patients return to working (median of 16 [ACDF] and 14 days [CDR]) and driving (median of 16 [ACDF] and 12 days [CDR])., Conclusions: The answers to the FAQs can assist surgeons in evidence-based patient counseling., (Copyright © 2024 by the American Academy of Orthopaedic Surgeons.)

Objective: The aim of this study was to provide benchmarks for the rates of complications by type of surgery performed., Study Design: Prospective multicenter database., Background: We have previously examined overall construct survival and complication rates for ASD surgery. However, the relationship between type of surgery and construct survival warrants more detailed assessment., Materials and Methods: Eight surgical scenarios were defined based on the levels treated, previous fusion status [primary (P) vs. revision (R)], and three-column osteotomy use (3CO): short lumbar fusion, LT-pelvis with 5 to 12 levels treated (P, R, or 3CO), UT-pelvis with 13 levels treated (P, R, or 3CO), and thoracic to lumbar fusion without pelvic fixation, representing 92.4% of the case in the cohort. Complication rates for each type were calculated and Kaplan-Meier curves with multivariate Cox regression analysis was used to evaluate the effect of the case characteristics on construct survival rate, while controlling for patient profile., Results: A total of 1073 of 1494 patients eligible for 2-year follow-up (71.8%) were captured. Survival curves for major complications (with or without reoperation), while controlling for demographics differed significantly among surgical types ( P <0.001). Fusion procedures short of the pelvis had the best survival rate, while UT-pelvis with 3CO had the worst survival rate. Longer fusions and more invasive operations were associated with lower 2-year complication-free survival, however, there were no significant associations between type of surgery and renal, cardiac, infection, wound, gastrointestinal, pulmonary, implant malposition, or neurological complications (all P >0.5)., Conclusions: This study suggests that there is an inherent increased risk of complication for some types of ASD surgery independent of patient profile. The results of this paper can be used to produce a surgery-adjusted benchmark for ASD surgery with regard to complications and survival. Such a tool can have very impactful applications for surgical decision-making and more informed patient counseling., Level of Evidence: Level III., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: The literature is scarce in exploring the role of imaging parameters like ultrasound (US) as a biomarker for surgical outcomes. The purpose of this study is to investigate the associations between skin US parameters and revision surgery following spine lumbar fusion., Methods: Posterior lumbar fusion patients with 2-years follow-up were assessed. Previous fusion or revision not due to adjacent segment disease (ASD) were excluded. Revisions were classified as cases and non-revision were classified as controls. US measurements conducted at two standardized locations on the lumbar back. Skin echogenicity of the average dermal (AD), upper 1/3 of the dermal (UD), lower 1/3 of the dermal (LD), and subcutaneous layer were measured. Echogenicity was calculated with the embedded echogenicity function of our institution's imaging platform (PACS). Statistical significance was set at p < 0.05., Results: A total of 128 patients (51% female, age 62 [54-72] years) were included in the final analysis. 17 patients required revision surgery. AD, UD, and LD echogenicity showed significantly higher results among revision cases 124.5 [IQR = 115.75,131.63], 128.5 [IQR = 125,131.63] and 125.5 [IQR = 107.91,136.50] compared to the control group 114.3 [IQR = 98.83,124.8], 118.5 [IQR = 109.28,127.50], 114 [IQR = 94.20,126.75] respectively., Conclusion: The findings of this study demonstrate a significant association between higher echogenicity values in different layers of the dermis and requiring revision surgery. The results provide insights into the potential use of skin US parameters as predictors for revision surgery. These findings may reflect underlying alterations in collagen. Further research is warranted to elucidate the mechanisms driving these associations., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background Context: Isolated decompression and decompression with instrumented fusion are accepted surgical treatments for lumbar spondylolisthesis. Although isolated decompression is a less costly solution with similar patient-reported outcomes, it is associated with higher rates of reoperation than primary fusion., Purpose: To determine the costs associated with primary decompression, primary fusion, and decompression and fusion for degenerative spondylolisthesis. We further sought to establish at what revision rate is primary decompression still a less costly surgical treatment for degenerative lumbar spondylolisthesis., Study Design/setting: A retrospective database study of the Medicare Provider Analysis and Review (MEDPAR) limited data set., Patient Sample: Patients who underwent single-level fusion or decompression for degenerative spondylolisthesis., Outcome Measures: Cost of surgical care., Methods: All inpatient stays that underwent surgery for single-level lumbar/lumbosacral degenerative spondylolisthesis in the 2019 calendar year (n=6,653) were queried from the MEDPAR limited data set. Patients were stratified into three cohorts: primary decompression (n=300), primary fusion (n=5,757), and revision fusion (n=566). Univariate analysis was conducted to determine cost differences between these groups and results were confirmed with multivariable regression. An economic analysis was then done to determine at what revision rate would primary decompression still be a less costly treatment choice., Results: on univariate analysis, the cost of primary single-level decompression for spondylolisthesis was $14,690±9,484, the cost of primary single-level fusion was $26,376±11,967, and revision fusion was $26,686±11,309 (p<0.001). on multivariate analysis, primary fusion was associated with an increased cost of $3,751, and revision fusion was associated with increased cost of $7,502 (95%ci: 2,990-4,512, p<0.001). economic analysis found that a revision rate less than or equal to 43.8% would still result in primary decompression being less costly for a practice than primary fusion for all patients., Conclusions: Isolated decompression for degenerative lumbar spondylolisthesis is a less costly treatment choice even with rates of revision fusion as high as 43.8%. This was true even with an assumed revision rate of 0% after primary fusion. This study solely looks at cost data, however, and many patients may still benefit from primary fusion when appropriately indicated., Competing Interests: Declaration of competing interest One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: The objective was to evaluate factors associated with the long-term durability of outcomes in adult spinal deformity (ASD) patients., Methods: Operative ASD patients fused from at least L1 to the sacrum with baseline (BL) to 5-year (5Y) follow-up were included. Substantial clinical benefit (SCB) in Oswestry Disability Index (ODI), numeric rating scale (NRS)-back, NRS-leg, and Scoliosis Research Society (SRS)-22r scores and physical component score were assessed on the basis of previously published values. Factors were evaluated on the basis of meeting optimal outcomes (OO) at 2 years (2+) and 5 years (5+). Furthermore, 2+ patients were isolated and evaluated on the basis of meeting OO at 5 years (2+5+) or not at 5 years (2+5-). OO were defined as follows: no reoperation, major mechanical failure, proximal junctional failure, and meeting either 1) SCB in terms of ODI score (decrease > 18.8) or 2) ODI < 15 and SRS-22r total > 4.5., Results: In total, 330 ASD patients met the inclusion criteria, with 45.5% meeting SCB for ODI at 2 years, while 46.0% met SCB at 5 years; 79% of those who achieved 2-year (2Y) SCB went on to achieve 5Y SCB. This rate was lower for OO, with 41% achieving 2Y OO (2+), while 37% met 5Y OO (5+) and 80% of 2+ patients had durable outcomes until 5+ (32% of the total cohort). Of the patient factors, frailty was significantly different among groups at 2 years, while comorbidity burden was significantly different at 5 years and the combination thereof differed in those with durable outcomes. Those who regained their level of activity postoperatively had 4 times higher odds of maintaining OO from 2 years to 5 years (p < 0.05). Osteoporosis rates, although equivocal at BL, were higher at the last follow-up in those who met 2Y OO but failed to meet 5Y OO. The odds of achieving OO at 5 years in 2+ patients decreased by 47% for each additional comorbidity and decreased by 74% in those who had lower-extremity paresthesias at BL (both p < 0.05). Controlling for patient factors and BL disability found fewer levels fused, decreased correction of sagittal vertical axis, and increased correction of pelvic incidence-lumbar lordosis mismatch to be predictive of maintaining 2Y OO until 5 years (p < 0.05)., Conclusions: SCB was met in 46% of ASD patients at 5 years. The durability of OO was seen in a third of patients until 5 years postoperatively. Higher rates of medical complications were seen in those who failed to achieve and maintain OO until 5 years. Frailty and comorbidity burden were significant factors associated with the achievement and durability of OO until 5 years.

Objective: Prior studies investigating the use of minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) for treatment of degenerative lumbar conditions and concomitant sagittal deformity have not stratified patients by preoperative pelvic incidence (PI)-lumbar lordosis (LL) mismatch, which is the earliest parameter to deteriorate in mild sagittal deformity. Thus, the aim of the present study was to determine the impact of preoperative PI-LL mismatch on clinical outcomes and sagittal balance restoration among patients undergoing MI-TLIF for degenerative spondylolisthesis (DS)., Methods: Consecutive adult patients undergoing primary 1-level MI-TLIF between April 2017 and April 2022 for DS with ≥ 6 months radiographic follow-up were included. Patient-reported outcome measures (PROMs) included the Oswestry Disability Index, visual analog scale (VAS), 12-Item Short-Form Health Survey (SF-12), and Patient-Reported Outcomes Measurement Information System at preoperative, early postoperative (< 6 months), and late postoperative (≥ 6 months) time points. The minimal clinically important difference (MCID) for PROMs was also evaluated. Radiographic parameters included PI, LL, pelvic tilt (PT), and sagittal vertical axis (SVA). Patients were categorized into balanced and unbalanced groups based on preoperative PI-LL mismatch according to age-adjusted alignment goals. Changes in radiographic parameters and PROMs were evaluated., Results: Eighty patients were included (L4-5 82.5%, grade I spondylolisthesis 82.5%, unbalanced 58.8%). Mean clinical and radiographic follow-up were 17.0 and 8.3 months, respectively. The average preoperative PI-LL was 18.8° in the unbalanced group and -3.3° in the balanced group. Patients with preoperative PI-LL mismatch had significantly worse preoperative PT (26.2° vs 16.4°, p < 0.001) and SVA (53.2 vs 9.0 mm, p = 0.001) compared with balanced patients. Patients with preoperative PI-LL mismatch also showed significantly worse PI-LL (16.0° vs 0.54°, p < 0.001), PT (25.9° vs 18.7°, p < 0.001), and SVA (49.4 vs 22.8 mm, p = 0.013) at long-term follow-up. No significant radiographic improvement was observed among unbalanced patients. All patients demonstrated significant improvements in all PROMs (p < 0.05) except for SF-12 mental component score. Achievement of MCID for VAS back score was significantly greater among patients with preoperative PI-LL mismatch (85.7% vs 65.5%, p = 0.045)., Conclusions: Although 1-level MI-TLIF did not restore sagittal alignment in patients with preoperative PI-LL mismatch, patients presenting with DS can expect significant improvement in PROMs following 1-level MI-TLIF regardless of preoperative alignment or extent of correction. Thus, attaining good clinical outcomes in patients with mild sagittal imbalance may not require addressing imbalance directly.

Introduction: Effective tools to evaluate bone quality preoperatively are scarce and the standard method to determine bone quality requires an invasive biopsy. A non-invasive, and preoperatively available method for bone quality assessment would be of clinical value. The purpose of this study is to investigate the associations of bone formation marker, serum bone alkaline phosphatase (BAP), and bone resorption marker, urine collagen cross-linked N-telopeptide (uNTX) to volumetric bone mineral density (vBMD), fluorescent advanced glycation endproducts (fAGEs) and bone microstructure., Materials and Methods: A cross-secional analysis using prospective data of patients undergoing lumbar spinal fusion was performed. BAP and uNTX were preoperatively collected. Quantitative computed tomography (QCT) was performed at the lumbar spine (vBMD ≤ 120 mg/cm 3 osteopenic/osteoporotic). Bone biopsies from the posterior superior iliac spine were obtained and evaluated with multiphoton fluorescence microscopy for fAGEs and microcomputed tomography (µCT) for bone microarchitecture. Correlations between BAP/uNTX to vBMD, fAGEs and µCT parameters were assessed with Spearman's ρ. Receiver operating characteristic (ROC) analysis evaluated BAP and uNTX as predictors for osteopenia/osteoporosis. Multivariable linear regression models adjusting for age, sex, BMI, race and diabetes mellitus determined associations between BAP/uNTX and fAGEs., Results: 127 prospectively enrolled patients (50.4% female, 62.5 years, BMI 28.7 kg/m 2 ) were analyzed. uNTX (ρ=-0.331,p < 0.005) and BAP (ρ=-0.245,p < 0.025) decreased with cortical fAGEs, and uNTX (ρ=-0.380,p < 0.001) decreased with trabecular fAGEs. BAP and uNTX revealed no significant correlation with vBMD. ROC analysis for BAP and uNTX discriminated osteopenia/osteoporosis with AUC of 0.477 and 0.561, respectively. In the multivariable analysis, uNTX decreased with increasing trabecular fAGEs after adjusting for covariates (β = 0.923;p = 0.031)., Conclusion: This study demonstrated an inverse association of bone turnover markers and fAGEs. Both uNTX and BAP could not predict osteopenia/osteoporosis in the spine. uNTX reflects collagen characteristics and might have a complementary role to vBMD, as a non-invasive tool for bone quality assessment in spine surgery., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background Context: Racial disparities in spine surgery have been thoroughly documented in the inpatient (IP) setting. However, despite an increasing proportion of procedures being performed as same-day surgeries, whether similar differences have developed in the outpatient (OP) setting remains to be elucidated., Purpose: This study aimed to investigate racial differences in postoperative outcomes between Black and White patients following OP and IP lumbar and cervical spine surgery., Study Design/setting: Retrospective cohort study., Patient Sample: Patients who underwent IP or OP microdiscectomy, laminectomy, anterior cervical discectomy and fusion (ACDF), or cervical disc replacement (CDR) between 2017 and 2021., Outcome Measures: Thirty-day rates of serious and minor adverse events, readmission, reoperation, nonhome discharge, and mortality., Methods: A retrospective review of patients who underwent IP or OP microdiscectomy, laminectomy, anterior cervical discectomy and fusion (ACDF), or cervical disc replacement (CDR) between 2017 and 2021 was conducted using the National Surgical Quality Improvement Program (NSQIP) database. Disparities between Black and White patients in (1) adverse event rates, (2) readmission rates, (3) reoperation rates, (4) nonhome discharge rates, (5) mortality rates, (6) operative times, and (7) hospital LOS between Black and White patients were measured and compared between IP and OP surgical settings. Multivariable logistic regression analyses were used to adjust for potential effects of baseline demographic and clinical differences., Results: Of 81,696 total surgeries, 49,351 (60.4%) were performed as IP and 32,345 (39.6%) were performed as OP procedures. White patients accounted for a greater proportion of IP (88.2% vs 11.8%) and OP (92.7% vs 7.3%) procedures than Black patients. Following IP surgery, Black patients experienced greater odds of serious (OR 1.214, 95% CI 1.077-1.370, p=.002) and minor adverse events (OR 1.377, 95% CI 1.113-1.705, p=.003), readmission (OR 1.284, 95% CI 1.130-1.459, p<.001), reoperation (OR 1.194, 95% CI 1.013-1.407, p=.035), and nonhome discharge (OR 2.304, 95% CI 2.101-2.528, p<.001) after baseline adjustment. Disparities were less prominent in the OP setting, as Black patients exhibited greater odds of readmission (OR 1.341, 95% CI 1.036-1.735, p=.026) but were no more likely than White patients to experience adverse events, reoperation, individual complications, nonhome discharge, or death (p>.050 for all)., Conclusions: Racial inequality in postoperative complications following spine surgery is evident, however disparities in complication rates are relatively less following OP compared to IP procedures. Further work may be beneficial in elucidating the causes of these differences to better understand and mitigate overall racial disparities within the inpatient setting. These decreased differences may also provide promising indication that progress towards reducing inequality is possible as spine care transitions to the OP setting., Competing Interests: Declaration of competing interest One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Study Design: Retrospective cohort study., Objective: To compare elective single-level anterior cervical discectomy and fusion (ACDF) versus posterior cervical decompression and fusion (PCDF) for degenerative cervical myelopathy (DCM) in terms of (1) cost, (2) length of hospital stay, and (3) discharge destination in Medicare patients. A sub-analysis of potential cost drivers was also performed., Background: In the era of value-based medicine, there is substantial interest in reducing the cost of care. Both ACDF and PCDF are used to treat DCM but carry different morbidity and risk profiles that can impact hospital resource utilization. However, this has not been assessed on a national level., Methods: Patients undergoing single-level elective ACDF and PCDF surgery were identified using the 2019 Medicare Provider Analysis and Review (MedPAR) Limited Data Set (LDS) and Centers for Medicare and Medicaid Services (CMS) 2019 Impact File. Multivariate models of hospital cost of care, length of stay, and discharge destination were performed, controlling for confounders. A univariate sub-analysis of 9 revenue centers was performed., Results: In all, 3942 patients met the inclusion criteria. The mean cost of elective single-level cervical fusion for myelopathy was $18,084±10,783, and the mean length of stay was 2.45±2.95 d. On multivariate analysis, ACDF was independently associated with decreased cost of $5,814 ( P <0.001), shorter length of stay by 1.1 days ( P <0.001), and decreased risk of nonhome discharge destination by 58% (adjusted odds ratio: 0.422, P <0.001).On sub-analysis of 9 revenue centers, medical/surgical supply ($10,497, 44%), operating room charges ($5401, 23%), and accommodations ($3999, 17%) were the largest drivers of charge differences., Conclusions: Single-level elective primary ACDF for DCM was independently associated with decreased cost, decreased hospital length of stay, and a lower rate of nonhome discharge compared with PCDF. Medical and surgical supply, operating room, and accommodation differences between ACDF and PCDF are potential areas for intervention. Increased granularity in reimbursement structures is warranted to prevent the creation of disincentives to the treatment of patients with DCM with pathology that is better addressed with PCDF., Level of Evidence: Level-III Retrospective Cohort Study., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective cohort study., Objective: The purpose of this study is to compare the impact of anterior cervical decompression and fusion (ACDF) versus posterior cervical decompression and fusion (PCDF) for the treatment of acute traumatic central cord syndrome (CCS) on hospital episodes of care in terms of (1) cost, (2) length of hospital stay, and (3) discharge destination., Summary of Background Data: Acute traumatic CCS is the most common form of spinal cord injury in the United States. CCS is commonly treated with surgical decompression and fusion. Hospital resource utilization based on surgical approach remains unclear., Methods: Patients undergoing ACDF and PCDF for acute traumatic CCS were identified using the 2019 Medicare Provider Analysis and Review Limited Data Set and Centers for Medicare and Medicaid Services 2019 Impact File. Multivariate models for hospital cost of care, length of stay, and discharge destination were performed, controlling for confounders. Subanalysis of accommodation and revenue center cost drivers was performed., Results: There were 1474 cases that met inclusion criteria: 673 ACDF (45.7%) and 801 PCDF (54.3%). ACDF was independently associated with a decreased cost of $9802 ( P <0.001) and a 59.2% decreased risk of discharge to nonhome destinations (adjusted odds ratio: 0.408, P <0.001). The difference in length of stay was not statistically significant. On subanalysis of cost drivers, ACDF was associated with decreased charges ($55,736, P <0.001) compared with PCDF, the largest drivers being the intensive care unit ($15,873, 28% of total charges, P <0.001) and medical/surgical supply charges ($19,651, 35% of total charges, P <0.001)., Conclusions: For treatment of acute traumatic CCS, ACDF was associated with almost $10,000 less expensive cost of care and a 60% decreased risk of discharge to nonhome destination compared with PCDF. The largest cost drivers appear to be ICU and medical/surgical-related. These findings may inform value-based decisions regarding the treatment of acute traumatic CCS. However, injury and patient clinical factors should always be prioritized in surgical decision-making, and increased granularity in reimbursement policies is needed to prevent financial disincentives in the treatment of patients with CCS better addressed with posterior approach-surgery., Competing Interests: N.U.A.: North American Spine Society: Board or committee member; Osseus: Other financial or material support; Research support; SeaSpine: Research support; and Spine, The Spine Journal: Editorial or governing board. T.J.A.: Augmedics: Stock or stock Options; Back Story, LLC: Board or committee member; Biomet: IP royalties; Care Equity: Stock or stock Options; CytoDyn Inc.: Stock or stock Options; DePuy, A Johnson & Johnson Company: IP royalties; Hospital for Special Surgery: Board or committee member; HS2, LLC: Stock or stock Options; In ViVo Therapeutics: Stock or stock Options; Innovative Surgical Designs, Inc.: Stock or stock Options; Journal of Bone and Joint Surgery—American: Editorial or governing board; JP Medical Publishers: Publishing royalties, financial or material support; Morphogenesis: Stock or stock Options; Nuvasive: Paid consultant; Orthopedics Today: Board or committee member; Editorial or governing board; Paradigm Spine: Stock or stock Options; Parvizi Surgical Innovations: Stock or stock Options; Physician Recommended Nutriceuticals: Stock or stock Options; Precision Orthopedics: Stock or stock Options; Pulse Equity: Stock or stock Options; Saunders/Mosby-Elsevier: Publishing royalties, financial or material support; Spine: Editorial or governing board; Spine Deformity Journal: Editorial or governing board; Spine Universe: Board or committee member; Spinicity: Stock or stock Options; Springer: Publishing royalties, financial or material support; Strathspey Crown: Stock or stock Options; Surg.IO LLC: Stock or stock Options; and Thieme: Publishing royalties, financial or material support. R.E.M.: Blue Cross Blue Shield Association Pharmacy & Medical Policy Committee: Other financial or material support; Blue Cross Blue Shield Medical Advisory Panel: Other financial or material support; and Clinical Orthopaedics and Related Research: Editorial or governing board. J.R.C.: Cervical Spine Research Society: Board or committee member; DePuy, A Johnson & Johnson Company: Research support; Evidence-based Spine Journal: Editorial or governing board; Evidence-based Spine Journal: Publishing royalties, financial or material support; Global Spine Journal: Publishing royalties, financial or material support; Globus Medical: Paid consultant; Journal of Spine: Editorial or governing board; Medtronic Sofamor Danek: Research support; Spine: Editorial or governing board; and Stryker: Research support. The authors do not have direct conflicts of interest in the manuscript. J.D., K.S., and C.B. have no conflicts to declare., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective analysis of prospectively enrolled patients., Objective: To evaluate the relationship between paraspinal muscle (PM) atrophy and Oswestry Disability Index (ODI) improvement after spinal fusion surgery for degenerative lumbar spondylolisthesis., Background: Atrophy of the PM is linked to multiple spinal conditions, sagittal malalignment, and increased postoperative complications. However, only limited evidence for the effect on patient-reported outcomes exists., Methods: Patients with degenerative lumbar spondylolisthesis undergoing decompression and fusion surgery were analyzed. Patients with missing follow-up, no imaging, or inadequate image quality were excluded. The ODI was assessed preoperatively and two years postoperatively. A cross-sectional area of the PM was measured on a T2-weighted magnetic resonance imaging sequence at the upper endplate of L4. On the basis of the literature, a 10-point improvement cutoff was defined as the minimum clinically important difference. Patients with a baseline ODI below the minimum clinically important difference were excluded. Logistic regression was used to calculate the association between fatty infiltration (FI) of the PM and improvement in ODI, adjusted for age, sex, and body mass index., Results: A total of 133 patients were included in the final analysis, with only two lost to follow-up. The median age was 68 years (IQR 62-73). The median preoperative ODI was 23 (IQR 17-28), and 76.7% of patients showed improvement in their ODI score by at least 10 points. In the multivariable regression, FI of the erector spinae and multifidus increased the risk of not achieving clinically relevant ODI improvement ( P =0.01 and <0.001, respectively). No significant association was found for the psoas muscle ( P =0.158)., Conclusions: This study demonstrates that FI of the erector spinae and multifidus is significantly associated with less likelihood of clinically relevant ODI improvement after decompression and fusion. Further research is needed to assess the effect of interventions., Competing Interests: A.A.S. reports royalties from Ortho Development, Corp.; private investments for Vestia Ventures MiRUS Investment, LLC, IVY II, LLC, ISPH II, LLC, ISPH 3, LLC, HS2, LLC, HSS ASC Development Network, LLC, and Centinel Spine (Vbros Venture Partners V); consulting fee from Depuy Synthes Products Inc., Clariance Inc., Kuros Biosciences AG, Ortho Development Corp., Medical Device Business Service Inc.; speaking and teaching arrangements of DePuy Synthes Products Inc.; membership of scientific advisory board of Depuy Synthes Products Inc., Clariance Inc., and Kuros Biosciences AG; Medical Device Business Service Inc. and trips/travel of Medical Device Business; research support from Spinal Kinetics Inc., outside the submitted work. Cammisa reports royalties from NuVasive Inc. Accelus; ownership interest for 4WEB Medical/4WEB Inc.; Healthpoint Capital Partners, LP; ISPH II, LLC; ISPH 3 Holdings, LLC; Ivy Healthcare Capital Partners, LLC; Medical Device Partners II, LLC; Medical Device Partners III, LLC; Orthobond Corporation; Spine Biopharma, LLC; Tissue Differentiation Intelligence, LLC; VBVP VI, LLC; VBVP X, LLC; Woven Orthopedics Technologies; consulting fees from 4WEB Medical/4WEB Inc., DePuy Synthes, NuVasive Inc., Spine Biopharma, LLC, and Synexis, LLC, Accelus; membership of scientific advisory board/other office of Healthpoint Capital Partners, Medical Device Partners II, LLC, Orthobond Corporation, Spine Biopharma, LLC, and Woven Orthopedic Technologies; and research support from 4WEB Medical/4WEB Inc., Mallinckrodt Pharmaceuticals, Camber Spine, and Centinel Spine, outside the submitted work. F.P.G. reports royalties from Lanx Inc., and Ortho Development Corp.; private investments for BCIMD; and stock ownership of Healthpoint Capital Partners, LP, outside the submitted work. A.P.H. reports research support from Kuros Biosciences AG and fellowship support from NuVasive Inc. and Kuros Biosciences BV, outside the submitted work. The remaining authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Hip osteoarthritis (OA) is common in patients with adult spinal deformity (ASD). Limited data exist on the prevalence of hip OA in patients with ASD, or on its impact on baseline and postoperative alignment and patient-reported outcome measures (PROMs). Therefore, this paper will assess the prevalence and impact of hip OA on alignment and PROMs., Methods: Patients with ASD who underwent L1-pelvis or longer fusions were included. Two independent reviewers graded hip OA with the Kellgren-Lawrence (KL) classification and stratified it by severity into non-severe (KL grade 1 or 2) and severe (KL grade 3 or 4). Radiographic parameters and PROMs were compared among 3 patient groups: Hip-Spine (hip KL grade 3 or 4 bilaterally), Unilateral (UL)-Hip (hip KL grade 3 or 4 unilaterally), or Spine (hip KL grade 1 or 2 bilaterally)., Results: Of 520 patients with ASD who met inclusion criteria for an OA prevalence analysis, 34% (177 of 520) had severe bilateral hip OA and unilateral or bilateral hip arthroplasty had been performed in 8.7% (45 of 520). A subset of 165 patients had all data components and were examined: 68 Hip-Spine, 32 UL-Hip, and 65 Spine. Hip-Spine patients were older (67.9 ± 9.5 years, versus 59.6 ± 10.1 years for Spine and 65.8 ± 7.5 years for UL-Hip; p < 0.001) and had a higher frailty index (4.3 ± 2.6, versus 2.7 ± 2.0 for UL-Hip and 2.9 ± 2.0 for Spine; p < 0.001). At 1 year, the groups had similar lumbar lordosis, yet the Hip-Spine patients had a worse sagittal vertebral axis (SVA) measurement (45.9 ± 45.5 mm, versus 25.1 ± 37.1 mm for UL-Hip and 19.0 ± 39.3 mm for Spine; p = 0.001). Hip-Spine patients also had worse Veterans RAND-12 Physical Component Summary scores at baseline (25.7 ± 9.3, versus 28.7 ± 9.8 for UL-Hip and 31.3 ± 10.5 for Spine; p = 0.005) and 1 year postoperatively (34.5 ± 11.4, versus 40.3 ± 10.4 for UL-Hip and 40.1 ± 10.9 for Spine; p = 0.006)., Conclusions: This study of operatively treated ASD revealed that 1 in 3 patients had severe hip OA bilaterally. Such patients with severe bilateral hip OA had worse baseline SVA and PROMs that persisted 1 year following ASD surgery, despite correction of lordosis., Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: Funding for this study was received from DePuy Synthes Spine, NuVasive, and K2/Stryker. In addition, the International Spine Study Group reports grants to the foundation from Medtronic, Globus, Stryker, SI Bone, and Carlsmed. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJS/H962)., (Copyright © 2024 by The Journal of Bone and Joint Surgery, Incorporated.)

Purpose: This study evaluates the intraoperative and short-term complications associated with robotically assisted pedicle screw placement in pediatric posterior spinal fusion (PSF) from three surgeons at two different institutions., Methods: We retrospectively reviewed 334 pediatric patients who underwent PSF with robotic-assisted navigation at 2 institutions over 3 years (2020-2022). Five thousand seventy robotically placed screws were evaluated. Data collection focused on intraoperative and early postoperative complications with minimum 30-day follow-up. Patients undergoing revision procedures were excluded., Results: Intraoperative complications included 1 durotomy, 6 patients with neuromonitoring alerts not related to screw placement, and 62 screws (1.2%) with documented pedicle breaches, all of which were revised at time of surgery. By quartile, pedicle breaches statistically declined from first quartile to fourth quartile (1.8% vs. 0.56%, p < 0.05). No breach was associated with neuromonitoring changes or neurological sequelae. No spinal cord or vascular injuries occurred. Seventeen postoperative complications occurred in eleven (3.3%) of patients. There were five (1.5%) patients with unplanned return to the operating room., Conclusion: Robotically assisted pedicle screw placement was safely and reliably performed on pediatric spinal deformity by three surgeons across two centers, demonstrating an acceptable safety profile and low incidence of unplanned return to the operating room., (© 2024. The Author(s), under exclusive licence to Scoliosis Research Society.)

Background: The optimal configuration for spinopelvic fixation during multilevel spine fusion surgery for adult spine deformity remains unclear. Postoperative sacroiliac (SI) joint pain, S2AI screw loosening and implant breakage could be related to continued motion of the SI joint with use of only a single point of fixation across the SI joint., Methods: Prospective, international, multicenter randomized controlled trial of 222 patients with adult spine deformity scheduled for multilevel (4 or more levels) spine fusion surgery with pelvic fixation. Subjects were randomized to sacroalar (S2) iliac (S2AI) screws alone for pelvic fixation or S2AI + triangular titanium implants placed cephalad to S2AI screws. Quad rod techniques were not allowed or used. Baseline spinal deformity measures were read by an independent radiologist. Site-reported perioperative adverse events were reviewed by a clinical events committee. Quality of life questionnaires and other clinical outcomes are in process with planned 2-year follow-up., Results: One hundred thirteen participants were assigned to S2AI and 109 to S2AI + titanium triangular implants (TTI). 35/222 (16%) of all subjects had a history of SI joint pain or were diagnosed with SI joint pain during preoperative workup. Three-month follow-up was available in all but 4 subjects. TTI placement was successful in 106 of 109 (98%) subjects assigned to TTI. In 2 cases, TTI could not be placed due to anatomical considerations. Three TTI ventral iliac breaches were observed, all of which were managed non-surgically. One TTI subject had a transverse sacral fracture and 1 TTI subject had malposition of the implant requiring removal., Conclusions: SI joint pain is common in patients with adult spinal deformity who are candidates for multilevel spine fusion surgery. Concurrent placement of TTI parallel to S2AI screws during multilevel spine fusion surgery is feasible and safe. Further follow-up will help to determine the clinical value of this approach to augment pelvic fixation., (Crown Copyright © 2024. Published by Elsevier Inc. All rights reserved.)

Objective: The aim of this study was to investigate the influence of preoperatively assessed paraspinal muscle parameters on postoperative patient-reported outcomes and maintenance of cervical sagittal alignment after anterior cervical discectomy and fusion (ACDF)., Methods: Patients with preoperative and postoperative standing cervical spine lateral radiographs and preoperative cervical MRI who underwent an ACDF between 2015 and 2018 were reviewed. Muscles from C3 to C7 were segmented into 4 functional groups: anterior, posteromedial, posterolateral, and sternocleidomastoid. The functional cross-sectional area and also the percent fat infiltration (FI) were calculated for all groups. Radiographic alignment parameters collected preoperatively and postoperatively included C2-7 lordosis and C2-7 sagittal vertical axis (SVA). Neck Disability Index (NDI) scores were recorded preoperatively and at 2 and 4-6 months postoperatively. To investigate the relationship between muscle parameters and postoperative changes in sagittal alignment, multivariable linear mixed models were used. Multivariable linear regression models were used to analyze the correlations between the changes in NDI scores and the muscles' FI., Results: A total of 168 patients with NDI and 157 patients with sagittal alignment measurements with a median follow-up of 364 days were reviewed. The mixed models showed that a greater functional cross-sectional area of the posterolateral muscle group at each subaxial level and less FI at C4-6 were significantly associated with less progression of C2-7 SVA over time. Moreover, there was a significant correlation between greater FI of the posteromedial muscle group measured at the C7 level and less NDI improvement at 4-6 months after ACDF., Conclusions: The findings highlight the importance of preoperative assessment of the cervical paraspinal muscle morphology as a predictor for patient-reported outcomes and maintenance of C2-7 SVA after ACDF.

Purpose: This study aimed to investigate the impact of sarcopenia and lumbar paraspinal muscle composition (PMC) on patient-reported outcomes (PROs) after lumbar fusion surgery with 12-month follow-up (12 M-FU)., Methods: A prospective investigation of patients undergoing elective lumbar fusion was conducted. Preoperative MRI-based evaluation of the cross-sectional area (CSA), the functional CSA (fCSA), and the fat infiltration(FI) of the posterior paraspinal muscles (PPM) and the psoas muscle at level L3 was performed. Sarcopenia was defined by the psoas muscle index (PMI) at L3 (CSA Psoas [cm 2 ]/(patients' height [m]) 2 ). PROs included Oswestry Disability Index (ODI), 12-item Short Form Healthy Survey with Physical (PCS-12) and Mental Component Scores (MCS-12) and Numerical Rating Scale back and leg (NRS-L) pain before surgery and 12 months postoperatively. Univariate and multivariable regression determined associations among sarcopenia, PMC and PROs., Results: 135 patients (52.6% female, 62.1 years, BMI 29.1 kg/m 2 ) were analyzed. The univariate analysis demonstrated that a higher FI (PPM) was associated with worse ODI outcomes at 12 M-FU in males. Sarcopenia (PMI) and higher FI (PPM) were associated with worse ODI and MCS-12 at 12 M-FU in females. Sarcopenia and higher FI of the PPM are associated with worse PCS-12 and more leg pain in females. In the multivariable analysis, a higher preoperative FI of the PPM (β = 0.442; p = 0.012) and lower FI of the psoas (β = -0.439; p = 0.029) were associated with a worse ODI at 12 M-FU after adjusting for covariates., Conclusions: Preoperative FI of the psoas and the PPM are associated with worse ODI outcomes one year after lumbar fusion. Sarcopenia is associated with worse ODI, PCS-12 and NRS-L in females, but not males. Considering sex differences, PMI and FI of the PPM might be used to counsel patients on their expectations for health-related quality of life after lumbar fusion., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Pelvic fixation is commonly used in correcting pelvic obliquity in pediatric patients with neuromuscular scoliosis and in preserving stability in adult patients with lumbosacral spondylolisthesis or instances of traumatic or osteoporotic fracture. S2-alar-iliac screws are commonly used in this role and have been proposed to reduce implant prominence when compared to traditional pelvic fusion utilizing iliac screws. The aim of this technical note is to describe a technique for robotically navigated placement of S2-alar-iliac screws in pediatric patients with neuromuscular scoliosis, which (a) minimizes the significant exposure needed to identify a bony start point, (b) aids in instrumenting the irregular anatomy often found in patients with neuromuscular scoliosis, and (c) allows for greater precision than traditional open or fluoroscopic techniques. We present five cases that underwent posterior spinal fusion to the pelvis with this technique that demonstrate the safety and efficacy of this procedure., (© 2024. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Study Design: Retrospective cohort study., Objective: (1) To develop a reliable grading system to assess the severity of posterior intervertebral osteophytes and (2) to investigate the impact of posterior intervertebral osteophytes on clinical outcomes after L5-S1 decompression and fusion through anterior lumbar interbody fusion (ALIF) and minimally-invasive transforaminal lumbar interbody fusion (MIS-TLIF)., Background: There is limited evidence regarding the clinical implications of posterior lumbar vertebral body osteophytes for ALIF and MIS-TLIF surgeries and there are no established grading systems that define the severity of these posterior lumbar intervertebral osteophytes., Patients and Methods: A retrospective analysis of patients undergoing L5-S1 ALIF or MIS-TLIF was performed. Preoperative and postoperative patient-reported outcome measures of the Oswestry Disability Index (ODI) and leg Visual Analog Scale (VAS) at 2-week, 6-week, 12-week, and 6-month follow-up time points were assessed. Minimal clinically important difference (MCID) for ODI of 14.9 and VAS leg of 2.8 were utilized. Osteophyte grade was based on the ratio of osteophyte length to foraminal width. "High-grade" osteophytes were defined as a maximal osteophyte length >50% of the total foraminal width., Results: A total of 70 consecutive patients (32 ALIF and 38 MIS-TLIF) were included in the study. There were no significant differences between the two cohorts in patient-reported outcome measures or achievement of MCID for Leg VAS or ODI preoperatively or at any follow-ups. On multivariate analysis, neither the surgical approach nor the presence of high-grade foraminal osteophytes was associated with leg VAS or ODI scores at any follow-up time point. In addition, neither the surgical approach nor the presence of high-grade foraminal osteophytes was associated with the achievement of MCID for leg VAS or ODI at 6 months., Conclusion: ALIF and MIS-TLIF are both valid options for treating degenerative spine conditions and lumbar radiculopathy, even in the presence of high-grade osteophytes that significantly occupy the intervertebral foramen., Level of Evidence: 3., Competing Interests: M.S.F has the following disclosures: Johnson & Johnson: Paid consultant. S.Q. has the following disclosures: AMOpportunities: Other financial or material support; Annals of Translational Medicine: Editorial or governing board; Association of Bone and Joint Surgeons: Board or committee member; Cervical Spine Research Society: Board or committee member; Contemporary Spine Surgery: Editorial or governing board; Globus Medical: IP royalties; Paid consultant; Paid presenter or speaker; Hospital Special Surgery Journal: Editorial or governing board; HS2, LLC: Stock or stock Options; International Society for the Advancement of Spine Surgery (ISASS) - Program Committee member: Board or committee member; Lifelink.com: Other financial or material support; Lumbar Spine Research Society: Board or committee member; Minimally Invasive Spine Study Group: Board or committee member; North American Spine Society: Board or committee member; Simplify Medical, Inc.: Other financial or material support; Society of Minimally Invasive Spine Surgery (SMISS) - Program Committee member: Board or committee member; Spinal Simplicity: Other financial or material support; SpineGuard, Inc.: Paid consultant; Stryker: IP royalties; Paid consultant; Surgalign: Paid consultant; Tissue Differentiation Intelligence: Stock or stock Options; Viseon, Inc.: Paid consultant; Research support. S.I. has the following disclosures: Globus Medical: Paid presenter or speaker; Stryker: Paid presenter or speaker; Vertebral Columns/International Society for the Advancement of Spine Surgery (ISASS): Editorial or governing board. The remaining authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: Abdominal aortic calcification (AAC), often found incidentally on lateral lumbar radiographs, is increasingly recognized for its association with adverse outcomes in spine surgery. As a marker of advanced atherosclerosis affecting cardiovascular dynamics, this study evaluates AAC's impact on perioperative blood loss in posterior spinal fusion (PSF)., Methods: Patients undergoing PSF from March 2016 to July 2023 were included. Estimated blood loss (EBL) and total blood volume (TBV) were calculated. AAC was assessed on lateral lumbar radiographs according to the Kauppila classification. Predictors of the EBL-to-TBV ratio (%EBL/TBV) were examined via univariable and multivariable regression analyses, which adjusted for parameters such as hypertension and aspirin use., Results: A total of 199 patients (47.2% female) were analyzed. AAC was present in 106 patients (53.3%). AAC independently predicted %EBL/TBV, accounting for an increase in blood loss of 4.46% of TBV (95% CI 1.17-7.74, p = 0.008)., Conclusions: This is the first study to identify AAC as an independent predictor of perioperative blood loss in PSF. In addition to its link to degenerative spinal conditions and adverse postoperative outcomes, the relationship between AAC and increased blood loss warrants attention in patients undergoing PSF., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: To assess the characteristics and risk factors for decisional regret following corrective adult spinal deformity (ASD) surgery at our hospital., Methods: This is a retrospective cohort study of a single-surgeon ASD database. Adult patients (> 40 years) who underwent ASD surgery from May 2016 to December 2020 with minimum 2-year follow-up were included (posterior-only, ≥ 4 levels fused to the pelvis) (n = 120). Ottawa decision regret questionnaires, a validated and reliable 5-item Likert scale, were sent to patients postoperatively. Regret scores were defined as (1) low regret: 0-39 (2) medium to high regret: 40-100. Risk factors for medium or high decisional regret were identified using multivariate models., Results: Ninety patients were successfully contacted and 77 patients consented to participate. Nonparticipants were older, had a higher incidence of anxiety, and higher ASA class. There were 7 patients that reported medium or high decisional regret (9%). Ninety percentage of patients believed that surgery was the right decision, 86% believed that surgery was a wise choice, and 87% would do it again. 8% of patients regretted the surgery and 14% believed that surgery did them harm. 88% of patients felt better after surgery. On multivariate analysis, revision fusion surgery was independently associated with an increased risk of medium or high decisional regret (adjusted odds ratio: 6.000, 95% confidence interval: 1.074-33.534, p = 0.041)., Conclusions: At our institution, we found a 9% incidence of decisional regret. Revision fusion was associated with increased decisional regret. Estimates for decisional regret should be based on single-institution experiences given differences in patient populations., (© 2024. The Author(s), under exclusive licence to Scoliosis Research Society.)

Background: Multiple animal models have previously been utilized to investigate anterior fusion techniques, but a mouse model has yet to be developed. The purpose of this study was to develop murine anterior interbody and posterolateral fusion techniques., Methods: Mice underwent either anterior interbody or posterolateral spinal fusion. A protocol was developed for both procedures, including a description of the relevant anatomy. Samples were subjected to micro-computed tomography to assess fusion success and underwent biomechanical testing with use of 4-point bending. Lastly, samples were fixed and embedded for histologic evaluation., Results: Surgical techniques for anterior interbody and posterolateral fusion were developed. The fusion rate was 83.3% in the anterior interbody model and 100% in the posterolateral model. Compared with a control, the posterolateral model exhibited a greater elastic modulus. Histologic analysis demonstrated endochondral ossification between bridging segments, further confirming the fusion efficacy in both models., Conclusions: The murine anterior interbody and posterolateral fusion models are efficacious and provide an ideal platform for studying the molecular and cellular mechanisms mediating spinal fusion., Clinical Relevance: Given the extensive genetic tools available in murine disease models, use of fusion models such as ours can enable determination of the underlying genetic pathways involved in spinal fusion., Competing Interests: Disclosure: This study was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health (NIH) under award number T32-AR078751 (K.W.M.) and by NIH awards DP5OD021351 and R01AR075585 (M.B.G.). This study is also based on research supported by Pershing Square Sohn Cancer Research Alliance and Pershing Square Foundation MIND Prize awards to M.B.G. M.B.G. holds a Career Award for Medical Scientists from the Burroughs Welcome Fund. S.I. is supported by the Kellen Scholar Award. J.S. is supported by a Children’s Tumor Foundation Young Investigator Award (CTF-2023-01-005; https://doi.org/10.48105/CTF.CTF-2023-01-005.pc.gr.172007 ). A.R.Y. is supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under award number T32-AR071302-07. S.B. is supported by a National Research Foundation of Korea award funded by the Ministry of Education (NRF-2021R1A6A3A14038667), the Arthritis Grant Program from the Arthritis National Research Foundation (1065843), and Weill Cornell Medicine JumpStart Awards (Year 2022). S.D. is supported by an NIH K99 grant (DE031819-01), a Department of Defense grant (W81XWH-22-PRMRP-DA), and Weill Cornell Medicine JumpStart Awards (Year 2019). The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H833 )., (Copyright © 2024 by The Journal of Bone and Joint Surgery, Incorporated.)

Study Design: Cross-sectional survey and retrospective review of prospectively collected data., Objective: To explore how patients perceive their decision to pursue spine surgery for degenerative conditions and evaluate factors correlated with decisional regret., Summary of Background Data: Prior research shows that one-in-five older adults regret their decision to undergo spinal deformity surgery. However, no studies have investigated decisional regret in patients with degenerative conditions., Methods: Patients who underwent cervical or lumbar spine surgery for degenerative conditions (decompression, fusion, or disk replacement) between April 2017 and December 2020 were included. The Ottawa Decisional Regret Questionnaire was implemented to assess prevalence of decisional regret. Questionnaire scores were used to categorize patients into low (<40) or medium/high (≥40) decisional regret cohorts. Patient-reported outcome measures (PROMs) included the Oswestry Disability Index, Patient-reported Outcomes Measurement Information System, Visual Analog Scale (VAS) Back/Leg/Arm, and Neck Disability Index at preoperative, early postoperative (<6 mo), and late postoperative (≥6 mo) timepoints. Differences in demographics, operative variables, and PROMs between low and medium/high decisional regret groups were evaluated., Results: A total of 295 patients were included (mean follow-up: 18.2 mo). Overall, 92% of patients agreed that having surgery was the right decision, and 90% would make the same decision again. In contrast, 6% of patients regretted the decision to undergo surgery, and 7% noted that surgery caused them harm. In-hospital complications (P=0.02) and revision fusion (P=0.026) were significantly associated with higher regret. The medium/high decisional regret group also exhibited significantly worse PROMs at long-term follow-up for all metrics except VAS-Arm, and worse achievement of minimum clinically important difference for Oswestry Disability Index (P=0.007), Patient-Reported Outcomes Measurement Information System (P<0.0001), and VAS-Leg (P<0.0001)., Conclusions: Higher decisional regret was encountered in the setting of need for revision fusion, increased in-hospital complications, and worse PROMs. However, 90% of patients overall were satisfied with their decision to undergo spine surgery for degenerative conditions. Current tools for assessing patient improvement postoperatively may not adequately capture the psychosocial values and patient expectations implicated in decisional regret., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: The present study utilized recently developed in-construct measurements in simulations of cervical deformity surgery in order to assess undercorrection and predict distal junctional kyphosis (DJK)., Methods: A retrospective review of a database of operative cervical deformity patients was analyzed for severe DJK and mild DJK. C2-lower instrumented vertebra (LIV) sagittal angle (SA) was measured postoperatively, and the correction was simulated in the preoperative radiograph in order to match the C2-LIV by using the planning software. Linear regression analysis that used C2 pelvic angle (CPA) and pelvic tilt (PT) determined the simulated PT that matched the virtual CPA. Linear regression analysis was used to determine the C2-T1 SA, C2-T4 SA, and C2-T10 SA that corresponded to DJK of 20° and cervical sagittal vertical axis (cSVA) of 40 mm., Results: Sixty-nine cervical deformity patients were included. Severe and mild DJK occurred in 11 (16%) and 22 (32%) patients, respectively; 3 (4%) required DJK revision. Simulated corrections demonstrated that severe and mild DJK patients had worse alignment compared to non-DJK patients in terms of cSVA (42.5 mm vs 33.0 mm vs 23.4 mm, p < 0.001) and C2-LIV SVA (68.9 mm vs 57.3 mm vs 36.8 mm, p < 0.001). Linear regression revealed the relationships between in-construct measures (C2-T1 SA, C2-T4 SA, and C2-T10 SA), cSVA, and change in DJK (all R > 0.57, p < 0.001). A cSVA of 40 mm corresponded to C2-T4 SA of 10.4° and C2-T10 SA of 28.0°. A DJK angle change of 10° corresponded to C2-T4 SA of 5.8° and C2-T10 SA of 20.1°., Conclusions: Simulated cervical deformity corrections demonstrated that severe DJK patients have insufficient corrections compared to patients without DJK. In-construct measures assess sagittal alignment within the fusion separate from DJK and subjacent compensation. They can be useful as intraoperative tools to gauge the adequacy of cervical deformity correction.

Study Design: A retrospective analysis of prospectively collected data., Objective: To report the decision-making process for decompression alone (DA) and decompression and fusion (DF) at a tertiary orthopedic center and compare the operative outcomes between both groups., Background: Controversy exists around the optimal operative treatment for DLS, either with DF or DA. Although previous studies tried to establish specific indications, clinical decision-making algorithms are needed., Materials and Methods: Patients undergoing spinal surgery for DLS at L4/5 were retrospectively analyzed. A survey of spine surgeons was performed to identify factors influencing surgical decision-making, and their association with the surgical procedure was tested in the clinical data set. We then developed a clinical score based on the statistical analysis and survey results. The predictive capability of the score was tested in the clinical data set with a receiver operating characteristic (ROC) analysis. To evaluate the clinical outcome, two years follow-up postoperative Oswestry Disability Index (ODI), postoperative low back pain (LBP) (Numeric Analog Scale), and patient satisfaction were compared between the DF and DA groups., Results: A total of 124 patients were included in the analysis; 66 received DF (53.2%) and 58 DA (46.8%). Both groups showed no significant differences in postoperative ODI, LBP, or satisfaction. The degree of spondylolisthesis, facet joint diastasis and effusion, sagittal disbalance, and severity of LBP were identified as the most important factors for deciding on DA or DF. The area under the curve of the decision-making score was 0.84. At a cutoff of three points indicating DF, the accuracy was 80.6%., Conclusions: The two-year follow-up data showed that both groups showed similar improvement in ODI after both procedures, validating the respective decision. The developed score shows excellent predictive capabilities for the decision processes of different spine surgeons at a single tertiary center and highlights relevant clinical and radiographic parameters. Further studies are needed to assess the external applicability of these findings., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Systematic Review and Meta-analysis., Objective: The objective of this study is to synthesize the early data regarding and analyze the safety profile of outpatient lumbar fusion., Summary of Background Data: Performing lumbar fusion in an outpatient or ambulatory setting is becoming an increasingly employed strategy to provide effective value-based care. As this is an emerging option for surgeons to employ in their practices, the data is still in its infancy., Methods: This study was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies that described outcomes of inpatient and outpatient lumbar fusion cohorts were searched from PubMed, Medline, The Cochrane Library, and Embase. Rates of individual medical and surgical complications, readmission, and reoperation were collected when applicable. Patient-reported outcomes (PROMs) were additionally collected if reported. Individual pooled comparative meta-analysis was performed for outcomes of medical complications, surgical complications, readmission, and reoperation. PROMs were reviewed and qualitatively reported., Results: The search yielded 14 publications that compared outpatient and inpatient cohorts with a total of 75,627 patients. Odds of readmission demonstrated no significant difference between outpatient and inpatient cohorts [OR=0.94 (0.81-1.11)]. Revision surgery similarly was no different between the cohorts [OR=0.81 (0.57-1.15)]. Pooled medical and surgical complications demonstrated significantly decreased odds for outpatient cohorts compared with inpatient cohorts [OR=0.58 (0.34-0.50), OR=0.41 (0.50-0.68), respectively]. PROM measures were largely the same between the cohorts when reported, with few studies showing better ODI and VAS Leg outcomes among outpatient cohorts compared with inpatient cohorts., Conclusion: Preliminary data regarding the safety of outpatient lumbar fusion demonstrates a favorable safety profile in appropriately selected patients, with PROMs remaining comparable in this setting. There is no data in the form of prospective and randomized trials which is necessary to definitively change practice., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Case: A 69-year-old man underwent a C3-4 anterior cervical discectomy and fusion and developed postoperative hypoglossal and glossopharyngeal palsies that resolved with symptomatic treatment., Conclusion: Cranial nerve palsy is a rare and possibly under-reported injury after higher-level cervical spine surgery. Conscientious positioning and awareness of these nerves during surgical exposure are crucial to minimizing cranial nerve palsies. Proper workup to identify these palsies and differentiate them from other complications is necessary to guide proper treatment., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSCC/C292)., (Copyright © 2024 by The Journal of Bone and Joint Surgery, Incorporated.)

Study Design: Retrospective study of prospective collected data., Objective: To analyze the association between intervertebral vacuum phenomenon (IVP) and clinical parameters in patients with degenerative spondylolisthesis., Summary of Background Data: IVP is a sign of advanced disc degeneration. The correlation between IVP severity and low back pain in patients with degenerative spondylolisthesis has not been previously analyzed., Methods: We retrospectively analyzed patients with degenerative spondylolisthesis who underwent surgery. Vacuum phenomenon was measured on computed tomography scan and classified into mild, moderate, and severe. A lumbar vacuum severity (LVS) scale was developed based on vacuum severity. The associations between IVP at L4/5 and the LVS scale, preoperative and postoperative low back pain, as well as the Oswestry Disability Index was assessed. The association of IVP at L4/5 and the LVS scale and surgical decision-making, defined as decompression alone or decompression and fusion, was assessed through univariable logistic regression analysis., Results: A total of 167 patients (52.7% female) were included in the study. The median age was 69 years (interquartile range 62-72). Overall, 100 (59.9%) patients underwent decompression and fusion and 67 (40.1%) underwent decompression alone. The univariable regression demonstrated a significantly increased odds ratio (OR) for back pain in patients with more severe IVP at L4/5 [OR=1.69 (95% CI 1.12-2.60), P =0.01]. The univariable regressions demonstrated a significantly increased OR for increased disability with more severe L4/L5 IVP [OR=1.90 (95% CI 1.04-3.76), P =0.04] and with an increased LVS scale [OR=1.17 (95% CI 1.02-1.35), P =0.02]. IVP severity of the L4/L5 were associated with higher indication for fusion surgery., Conclusion: Our study showed that in patients with degenerative spondylolisthesis undergoing surgery, the severity of vacuum phenomenon at L4/L5 was associated with greater preoperative back pain and worse Oswestry Disability Index. Patients with severe IVP were more likely to undergo fusion., Competing Interests: A.A.S. reports royalties from Ortho Development, Corp.; private investments for Vestia Ventures MiRUS Investment, LLC, IVY II, LLC, ISPH II, LLC, ISPH 3, LLC, HSS ASC Development Network, LLC, and Centinel Spine (Vbros Venture Partners V); consulting fee from Depuy Synthes Products, Inc., Clariance, Inc., Kuros Biosciences AG, Ortho Development Corp., Medical Device Business Service, Inc.; speaking and teaching arrangements of DePuy Synthes Products, Inc.; membership of scientific advisory board of Depuy Synthes Products, Inc., Clariance, Inc., and Kuros Biosciences AG; Medical Device Business Service, Inc. and trips/travel of Medical Device Business; research support from Spinal Kinetics, Inc., outside the submitted work. F.P.C. reports royalties from NuVasive, Inc. Accelus; ownership interest for 4WEB Medical/4WEB, Inc.; Healthpoint Capital Partners, LP; ISPH II, LLC; ISPH 3 Holdings, LLC; Ivy Healthcare Capital Partners, LLC; Medical Device Partners II, LLC; Medical Device Partners III, LLC; Orthobond Corporation; Spine Biopharma, LLC; Tissue Differentiation Intelligence, LLC; VBVP VI, LLC; VBVP X, LLC; Woven Orthopedics Technologies; consulting fees from 4WEB Medical/4WEB, Inc., DePuy Synthes, NuVasive, Inc., Spine Biopharma, LLC, and Synexis, LLC, Accelus; membership of scientific advisory board/other office of Healthpoint Capital Partners, Medical Device Partners II, LLC, Orthobond Corporation, Spine Biopharma, LLC, and Woven Orthopedic Technologies; and research support from 4WEB Medical/4WEB, Inc., Mallinckrodt Pharmaceuticals, Camber Spine, and Centinel Spine, outside the submitted work. F.P.G. reports royalties from Lanx, Inc., and Ortho Development Corp.; private investments for BCIMD; and stock ownership of Healthpoint Capital Partners, LP, outside the submitted work. A.P.H. reports research support from Kuros Biosciences AG; and fellowship support from NuVasive, Inc. and Kuros Biosciences BV, outside the submitted work. G.S. receives consulting fees from Stryker and Camber spine. The remaining authors declare no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background Context: Degenerative lumbar spondylolisthesis (DLS) is a prevalent spinal disorder, often requiring surgical intervention. Accurately predicting surgical outcomes is crucial to guide clinical decision-making, but this is challenging due to the multifactorial nature of postoperative results. Traditional risk assessment tools have limitations, and with the advent of machine learning, there is potential to enhance the precision and comprehensiveness of preoperative evaluations., Purpose: We aimed to develop a machine-learning algorithm to predict surgical outcomes in patients with degenerative lumbar spondylolisthesis (DLS) undergoing spinal fusion surgery, only using preoperative data., Study Design: Retrospective cross-sectional study., Patient Sample: Patients with DLS undergoing lumbar spinal fusion surgery., Outcome Measures: This study aimed to predict the occurrence of lower back pain (LBP) ≥4 on the numeric analogue scale (NAS) 2 years after surgery. LBP was evaluated as the average pain patients experienced at rest in the week before questioning. NAS ranges from 0 to 10, 0 representing no pain and 10 representing the worst pain imaginable., Methods: We conducted a retrospective analysis of prospectively enrolled patients who underwent spinal fusion surgery for degenerative lumbar spondylolistheses at our institution in the United States between January 2016 and December 2018. The initial patient characteristics to be included in the training of the model were chosen by clinical expertise and through a literature review and included demographic characteristics, comorbidities, and radiologic features. The data was split into a training and validation datasets using a 60/40 split. Four different machine learning models were trained, including the modern XGBoost model, logistic regression, random-forest, and support vector machine (SVM). The models were evaluated according to the area under the curve (AUC) of the receiver operating characteristics (ROC) curve. An AUC of 0.7 to 0.8 was considered fair, 0.8 to 0.9 good, and ≥ 0.9 excellent. Additionally, a calibration plot and the Brier score were calculated for each model., Results: A total of 135 patients (66% female) were included. A total of 38 (28%) patients reported LBP ≥ 4 after 2 years, representing the positive class. The XGBoost model demonstrated the best performance in the validation set with an AUC of 0.81 (95% CI 0.67-0.95). The other machine learning models performed significantly worse: with an AUC of 0.52 (95% CI 0.37-0.68) for the SVM, 0.56 (95% CI 0.37-0.76) for the logistic regression and an AUC of 0.56 (95% CI 0.37-0.78) for the random forest. In the XGBoost model age, composition of the erector spinae, and severity of lumbar spinal stenosis as were identified as the most important features., Conclusions: This study represents a novel approach to predicting surgical outcomes in spinal fusion patients. The XGBoost demonstrated a better performance compared with classical models and highlighted the potential contributions of age and paraspinal musculature atrophy as significant factors. These findings have important implications for enhancing patient care through the identification of high-risk individuals and modifiable risk factors. As the incorporation of machine learning algorithms into clinical decision-making continues to gain traction in research and clinical practice, our insights reinforce this trajectory by showcasing the potential of these techniques in forecasting surgical results., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Study Design: Multicenter retrospective cohort study., Objective: To investigate risk factors for loss of correction within the instrumented lumbar spine after adult spinal deformity surgery., Summary of Background Data: The sustainability of adult spinal deformity surgery remains a health care challenge. Malalignment is a major reason for revision surgery., Patients and Methods: A total of 321 patients who underwent fusion of the lumbar spine (≥5 levels, LIV pelvis) with a revision-free follow-up of ≥3 years were identified. Patients were stratified by a change in pelvic incidence-lumbar lordosis from 6 weeks to 3 years postoperative as "maintained" versus "loss" >5°. Those with instrumentation failure (broken rod, screw pullout, etc .) were excluded before comparisons. Demographics, surgical data, and radiographic alignment were compared. Repeated measure analysis of variance was performed to evaluate the maintenance of the correction for L1-L4 and L4-S1. Multivariate logistic regression was conducted to identify independent surgical predictors of correction loss., Results: The cohort had a mean age of 64 years, a mean Body Mass Index of 28 kg/m 2 , and 80% females. Eighty-two patients (25.5%) lost >5° of pelvic incidence-lumbar lordosis correction (mean loss 10±5°). After the exclusion of patients with instrumentation failure, 52 losses were compared with 222 maintained. Demographics, osteotomies, 3CO, interbody fusion, use of bone morphogenetic protein, rod material, rod diameter, and fusion length were not significantly different. L1-S1 screw orientation angle was 1.3 ± 4.1 from early postoperative to 3 years ( P = 0.031), but not appreciably different at L4-S1 (-0.1 ± 2.9 P = 0.97). Lack of a supplemental rod (odds ratio: 4.0, P = 0.005) and fusion length (odds ratio 2.2, P = 0.004) were associated with loss of correction., Conclusions: Approximately, a quarter of revision-free patients lose an average of 10° of their 6-week correction by 3 years. Lordosis is lost proximally through the instrumentation ( i.e. tulip/shank angle shifts and/or rod bending). The use of supplemental rods and avoiding sagittal overcorrection may help mitigate this loss., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background Context: Various total disc replacement (TDR) designs have been compared to anterior cervical discectomy and fusion (ACDF) with favorable short and long-term outcomes in FDA-approved investigational device exemption (IDE) trials. The unique design of M6-C, with a compressible viscoelastic nuclear core and an annular structure, has previously demonstrated favorable clinical outcomes through 24 months., Purpose: To evaluate the long-term safety and effectiveness of the M6-C compressible artificial cervical disc and compare to ACDF at 5 years., Study Design: Prospective, multicenter, concurrently and historically controlled, FDA-approved IDE clinical trial., Patient Sample: Subjects with one-level symptomatic degenerative cervical radiculopathy were enrolled and received M6-C (n=160) or ACDF (n=189) treatment as part of the IDE study. Safety outcomes were evaluated at 5 years for all subjects. The primary effectiveness endpoint was available at 5 years for 113 M6-C subjects and 106 ACDF controls., Outcome Measures: The primary endpoint of this analysis was composite clinical success (CCS) at 60 months. Secondary endpoints were function and pain (neck disability index, VAS), physical quality of life (SF-36, SF-12), safety, neurologic, and radiographic assessments., Methods: Propensity score subclassification was used to control for selection bias and match baseline covariates of the control group to the M6-C subjects. Sixty-month CCS rates were estimated for each treatment group using a generalized linear model controlling for propensity score., Results: At 5 years postoperatively, the M6-C treatment resulted in 82.3% CCS while the ACDF group showed 67.0% CCS (superiority p=.013). Secondary endpoints indicated that significantly more M6-C subjects achieved VAS neck and arm pain improvements and showed maintained or improved physical functioning on quality-of-life measures compared to baseline assessments. The M6-C group-maintained flexion-extension motion, with significantly greater increases from baseline disc height and disc angle than observed in the control group. The rates of M6-C subsequent surgical interventions (SSI; 3.1%) and definitely device- or procedure-related serious adverse events (SAE failure; 3.1%) were similar to ACDF rates (SSI=5.3%, SAE failure=4.8%; p>.05 for both)., Conclusions: Subjects treated with the M6-C artificial disc demonstrated superior 5-year achievement of clinical success when compared to ACDF controls. In addition, significantly more subjects in the M6-C group showed improved pain and physical functioning scores than observed in ACDF subjects, with no difference in reoperation rates or safety outcomes., Competing Interests: Declaration of competing interest One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Study Design: Matched cohort comparison., Objective: To determine perioperative outcomes of erector spinae plane (ESP) block for minimally invasive transforaminal lumbar interbody fusion (MI-TLIF)., Summary of Background Data: There is a paucity of data on the impact of lumbar ESP block on perioperative outcomes and its safety in MI-TLIF., Materials and Methods: Patients who underwent 1-level MI-TLIF and received the ESP block (group E ) were included. An age and sex-matched control group was selected from a historical cohort that received the standard-of-care (group NE). The primary outcome of this study was 24-hour opioid consumption in morphine milligram equivalents. Secondary outcomes were pain severity measured by a numeric rating scale, opioid-related side effects, and hospital length of stay. Outcomes were compared between the two groups., Results: Ninety-eight and 55 patients were included in the E and NE groups, respectively. There were no significant differences between the two cohorts in patient demographics. Group E had lower 24-hour postoperative opioid consumption ( P = 0.117, not significant), reduced opioid consumption on a postoperative day (POD) 0 ( P = 0.016), and lower first pain scores postsurgery ( P < 0.001). Group E had lower intraoperative opioid requirements ( P < 0.001), and significantly lower average numeric rating scale pain scores on POD 0 ( P = 0.034). Group E reported fewer opioid-related side effects as compared with group NE, although this was not statistically significant. The average highest postoperative pain score within 3 hours postprocedurally was 6.9 and 7.7 in the E and NE cohorts, respectively ( P = 0.029). The median length of stay was comparable between groups with the majority of patients in both groups being discharged on POD 1., Conclusions: In our retrospective matched cohort, ESP blocks resulted in reduced opioid consumption and decreased pain scores on POD 0 in patients undergoing MI-TLIF., Level of Evidence: Level 3., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background: The Roussouly, SRS-Schwab, and Global Alignment and Proportion (GAP) classifications define alignment by spinal shape and deformity severity. The efficacy of different surgical approaches and techniques to successfully achieve these goals is not well understood., Purpose: Identify the impact of surgical approach and/or technique on meeting complex realignment goals in adult spinal deformity (ASD) corrective surgery., Study Design/setting: Retrospective study., Materials and Methods: Included patients with ASD fused to pelvis with 2-year data. Patients were categorized by: (1) Roussouly: matching current and theoretical spinal shapes, (2) improving in SRS-Schwab modifiers (0, +, ++), and (3) improving GAP proportionality by 2 years. Analysis of covariance and multivariable logistic regression analyses controlling for age, levels fused, baseline deformity, and 3-column osteotomy usage compared the effect of different surgical approaches, interbody, and osteotomy use on meeting realignment goals., Results: A total of 693 patients with ASD were included. By surgical approach, 65.7% were posterior-only and 34.3% underwent anterior-posterior approach with 76% receiving an osteotomy (21.8% 3-column osteotomy). By 2 years, 34% matched Roussouly, 58% improved in GAP, 45% in SRS-Schwab pelvic tilt (PT), 62% sagittal vertical axis, and 70% pelvic incidence-lumbar lordosis. Combined approaches were most effective for improvement in PT [odds ratio (OR): 1.7 (1.1-2.5)] and GAP [OR: 2.2 (1.5-3.2)]. Specifically, anterior lumbar interbody fusion (ALIF) below L3 demonstrated higher rates of improvement versus TLIFs in Roussouly [OR: 1.7 (1.1-2.5)] and GAP [OR: 1.9 (1.3-2.7)]. Patients undergoing pedicle subtraction osteotomy at L3 or L4 were more likely to improve in PT [OR: 2.0 (1.0-5.2)] and pelvic incidence-lumbar lordosis [OR: 3.8 (1.4-9.8)]. Clinically, patients undergoing the combined approach demonstrated higher rates of meeting SCB in Oswestry Disability Index by 2 years while minimizing rates of proximal junctional failure, most often with an ALIF at L5-S1 [Oswestry Disability Index-SCB: OR: 1.4 (1.1-2.0); proximal junctional failure: OR: 0.4 (0.2-0.8)]., Conclusions: Among patients undergoing ASD realignment, optimal lumbar shape and proportion can be achieved more often with a combined approach. Although TLIFs, incorporating a 3-column osteotomy, at L3 and L4 can restore lordosis and normalize pelvic compensation, ALIFs at L5-S1 were most likely to achieve complex realignment goals with an added clinical benefit and mitigation of junctional failure., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background Context: Navigation and robotic technologies have emerged as an alternative option to conventional freehand techniques for pedicle screw insertion. However, the effectiveness of these technologies in reducing the perioperative complications of spinal fusion surgery remains limited due to the small cohort size in the existing literature., Purpose: To investigate whether utilization of robotically navigated pedicle screw insertion can reduce the perioperative complications of spinal fusion surgery-including reoperations-with a sizeable cohort., Study Design: Retrospective study., Patient Sample: Patients who underwent primary lumbar fusion surgery between 2019 and 2022., Outcome Measures: Perioperative complications including readmission, reoperation, its reasons, estimated blood loss, operative time, and length of hospital stay., Methods: Patients' data were collected including age, sex, race, body mass index, upper-instrumented vertebra, lower-instrumented vertebra, number of screws inserted, and primary procedure name. Patients were classified into the following two groups: freehand group and robot group. The variable-ratio greedy matching was utilized to create the matched cohorts by propensity score and compared the outcomes between the two group., Results: A total of 1,633 patients who underwent primary instrumented spinal lumbar fusion surgery were initially identified (freehand 1,286; robot 347). After variable ratio matching was performed with age, sex, body mass index, fused levels, and upper instrumented vertebrae level, 694 patients in the freehand group and 347 patients in robot groups were selected. The robot group showed less estimated blood loss (418.9±398.9 vs 199.2±239.6 ml; p<.001), shorter LOS (4.1±3.1 vs 3.2±3.0 days; p<.001) and similar operative time (212.5 vs 222.0 minutes; p=.151). Otherwise, there was no significant difference in readmission rate (3.6% vs 2.6%; p=.498), reoperation rate (3.2% vs 2.6%; p=.498), and screw malposition requiring reoperation (five cases, 0.7% vs one case, 0.3%; p=1.000)., Conclusions: Perioperative complications requiring readmission and reoperation were similar between fluoroscopy guided freehand and robotic surgery. Robot-guided pedicle screw insertion can enhance surgical efficiency by reducing intraoperative blood loss and length of hospital stay without extending operative time., Competing Interests: Declaration of Competing Interest One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Purpose: This study aims to investigate the fusion rate and complications associated with trans-sacral interbody fusion (TSIF) in long fusions to the sacrum for adult spinal deformity (ASD) over a two year follow-up period. Potential predictor variables associated with pseudarthrosis were also examined., Methods: A retrospective clinical review was conducted on a consecutive series of ASD patients who underwent long fusions to the sacrum, with TSIF performed as a same-day or staged procedure. Patient demographics, bone mineral density, operative details, perioperative and late complications, and fusion rates were reviewed. Univariate analysis was used to identify the risk factors associated with pseudarthrosis., Results: The study included 43 patients with an average age of 55.3 ± 8.9 years. The perioperative complication rate was 28%, with 12% of the complications directly related to TSIF. The late complication rate was 33%, with 16% related to TSIF. The most common complications were pseudarthrosis (14%) and postoperative ileus (7%). The overall radiographic fusion rate at two years was 86%. Univariate analysis revealed that revision surgery was significantly associated with pseudarthrosis (p = 0.027). Over the follow-up period, patients who underwent TSIF during long posterior fusions to the sacrum showed improvement in overall SRS scores, ODI scores, and SF-36 physical health and mental health (p < 0.05)., Conclusion: TSIF is a relatively safe and minimally invasive method for achieving interbody fusion at the lumbosacral junction in the treatment of ASD, with acceptable fusion rates and a low complication rate. However, TSIF is not recommended for revision reconstruction in ASD., (© 2023. The Author(s) under exclusive licence to SICOT aisbl.)

Study Design: Retrospective review of a prospectively maintained multisurgeon registry., Objective: To study recovery kinetics and associated factors after cervical spine surgery., Summary of Background Data: Few studies have described return to activities cervical spine surgery. This is a big gap in the literature, as preoperative counseling and expectations before surgery are important., Materials and Methods: Patients who underwent either anterior cervical discectomy and fusion (ACDF) or cervical disk replacement (CDR) were included. Data collected included preoperative patient-reported outcome measures, return to driving, return to working, and discontinuation of opioids data. A multivariable regression was conducted to identify the factors associated with return to driving by 15 days, return to working by 15 days, and discontinuing opioids by 30 days., Results: Seventy ACDF patients and 70 CDR patients were included. Overall, 98.2% of ACDF patients and 98% of CDR patients returned to driving in 16 and 12 days, respectively; 85.7% of ACDF patients and 90.9% of CDR patients returned to work in 16 and 14 days; and 98.3% of ACDF patients and 98.3% of CDR patients discontinued opioids in a median of seven and six days. Though not significant, minimal (odds ratio (OR)=1.65) and moderate (OR=1.79) disability was associated with greater odds of returning to driving by 15 days. Sedentary work (OR=0.8) and preoperative narcotics (OR=0.86) were associated with decreased odds of returning to driving by 15 days. Medium (OR=0.81) and heavy (OR=0.78) intensity occupations were associated with decreased odds of returning to work by 15 days. High school education (OR=0.75), sedentary work (OR=0.79), and retired/not working (OR=0.69) were all associated with decreased odds of discontinuing opioids by 30 days., Conclusions: Recovery kinetics for ACDF and CDR are comparable. Most patients return to all activities after ACDF and CDR within 16 days. These findings serve as an important compass for preoperative counseling., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: A nicotine-impaired spinal fusion rabbit model., Objective: To examine whether controlled delivery of morselized absorbable collagen sponge recombinant human bone morphogenetic protein-2 (rhBMP2) in a delayed manner postsurgery would allow for improved bone healing., Summary of Background Data: The current delivery method of rhBMP-2 during surgery causes a burst of rhBMP-2, which is not sustained. Given that bone morphogenetic protein 2 (BMP-2) expression peaks later in the fusion process, there may be the benefit of delivery of rhBMP-2 later in the healing process., Methods: Sixteen male 1-year-old rabbits underwent a posterolateral spinal fusion with iliac crest bone graft at L5-L6 while being given nicotine to prevent spinal fusion as previously published. Eight were controls, whereas 8 had morselized rhBMP-2 (4.2 mg) injected at the fusion site at 4 weeks postoperatively. Histologic, radiologic, and palpation examinations were performed at 12 weeks to determine fusion status and the volume of bone formed. Hematoxylin and eosin stains were used for histology. A Student t test was used to compare the computed tomography scan measured volume of bone created between the control cohort (CC) and rhBMP-2 delayed delivery cohort (BMP-DDC)., Results: Of the total, 7/8 rabbits in the BMP-DDC and 5/8 rabbits in the CC formed definitive fusion with a positive palpation examination, bridging bone between transverse processes on computed tomography scan, and an x-ray showing fusion. Histologic analysis revealed newly remodeled bone within the BMP-DDC. There was an increased average volume of bone formed within the BMP-DDC versus the CC (22.6 ± 13.1 vs 11.1 ± 3.6 cm 3 , P = 0.04)., Conclusion: Our study shows that injectable morselized absorbable collagen sponge/rhBMP-2 can create twice as much bone within a nicotine-impaired rabbit spine fusion model when delivered 4 weeks out from the time of surgery., Competing Interests: The authors declare no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective review of prospectively collected multisurgeon data., Objective: Examine the rate, clinical impact, and predictors of subsidence after expandable minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) cage., Summary of Background Data: Expandable cage technology has been adopted in MI-TLIF to reduce the risks and optimize outcomes. Although subsidence is of particular concern when using expandable technology as the force required to expand the cage can weaken the endplates, its rates, predictors, and outcomes lack evidence., Materials and Methods: Patients who underwent 1 or 2-level MI-TLIF using expandable cages for degenerative lumbar conditions and had a follow-up of >1 year were included. Preoperative and immediate, early, and late postoperative radiographs were reviewed. Subsidence was determined if the average anterior/posterior disc height decreased by >25% compared with the immediate postoperative value. Patient-reported outcomes were collected and analyzed for differences at the early (<6 mo) and late (>6 mo) time points. Fusion was assessed by 1-year postoperative computed tomography., Results: One hundred forty-eight patients were included (mean age, 61 yr, 86% 1-level, 14% 2-level). Twenty-two (14.9%) demonstrated subsidence. Although statistically not significant, patients with subsidence were older, had lower bone mineral density, and had higher body mass index and comorbidity burden. Operative time was significantly higher ( P = 0.02) and implant width was lower ( P < 0.01) for subsided patients. Visual analog scale-leg was significantly lower for subsided patients compared with nonsubsided patients at a >6 months time point. Long-term (>6 mo) patient-acceptable symptom state achievement rate was lower for subsided patients (53% vs . 77%), although statistically not significant ( P = 0.065). No differences existed in complication, reoperation, or fusion rates., Conclusions: Of the patients, 14.9% experienced subsidence predicted by narrower implants. Although subsidence did not have a significant impact on most patient-reported outcome measures and complication, reoperation, or fusion rates, patients had lower visual analog scale-leg and patient-acceptable symptom state achievement rates at the >6-month time point., Level of Evidence: Level 4., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)