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Minimally invasive spine surgery (MISS) techniques were developed to address morbidities associated with open spinal surgery approaches. MISS was initially applied for indications such as the microendoscopic decompression of stenosis (MEDS)-an operation that has become widely implemented in modern spine surgery practice. Minimally invasive surgery for MEDS is an excellent example of how an MISS technique has improved outcomes compared with the use of traditional open surgical procedures. In parallel with reports of surgeon experience, accumulating clinical evidence suggests that MISS is favoured over open surgery, and one could argue that the role of MISS techniques will continue to expand. As the field of minimally invasive surgery has developed, MISS has been implemented for the treatment of increasingly difficult and complex pathologies, including trauma, spinal malignancies and spinal deformity in adults. In this Review, we present the accumulating evidence in support of minimally invasive techniques for established MISS indications, such as lumbar stenosis, and discuss the need for additional level I and level II data to demonstrate the benefit of MISS over traditional open surgery. The expanding utility of MISS techniques to address an increasingly broad range of spinal pathologies is also highlighted. [ABSTRACT FROM AUTHOR]

Objective: The goal of this study was to compare the impact of using a lower thoracic (LT) versus upper lumbar (UL) level as the upper instrumented vertebra (UIV) on clinical and radiographic outcomes following minimally invasive surgery for adult spinal deformity., Methods: A multicenter retrospective study design was used. Inclusion criteria were age ≥ 18 years, and one of the following: coronal Cobb angle > 20°, sagittal vertical axis > 50 mm, pelvic tilt > 20°, pelvic incidence-lumbar lordosis mismatch > 10°. Patients were treated with circumferential or hybrid minimally invasive techniques at ≥ 3 spinal levels and had a 2-year minimum follow-up. They were then divided into 2 groups depending on whether the UIV was in the UL region, defined as a UIV location of L1-2, or the LT region, defined as T10-12., Results: A total of 114 of 223 patients met the inclusion criteria (68 LT and 46 UL). The UL group was older (67.5 vs 62.3 years; p = 0.015). Preoperative spinopelvic parameters were similar, except for sacral slope, which was higher in the UL group (30.5° vs 26.5°; p < 0.001). The percentage of patients with fixation crossing the lumbosacral junction was also similar (70.6% vs 67.4%; p = 0.717). Postoperative lumbar lordosis (42.5° vs 35.5°; p = 0.01) and change in coronal Cobb angle (-23.2° vs -9.6°; p < 0.001) were greater in the LT group, but other changes in postoperative spinopelvic parameters and changes in health-related quality-of-life scores were similar between groups. Reoperation rates were lower in the UL group (17.4% vs 36.8%; p = 0.025), largely associated with fewer radiographic failures (UL = 10.9% vs LT = 26.5%; p = 0.042); however, overall complication rates were not significantly different (UL = 43.5% vs LT = 60.3%; p = 0.077)., Conclusions: Selecting a UL vertebra for UIV in minimally invasive surgical correction of adult spinal deformity results in lower reoperation rates compared to extending fixation to the LT region. This choice also correlates with shorter operating room times and reduced estimated blood loss. Although extending fixation to the LT region is associated with slightly greater lumbar lordosis and a greater change in the coronal Cobb angle, clinical outcomes were similar between the LT and UL groups for UIV.

Objective: Many studies have compared outcomes following anterior and posterior cervical fusion, yet the differences in the impacts of perioperative complications on outcomes have not been well studied. This study aimed to assess the differences in the effects of 30-day perioperative complications on patient-reported outcome measures (PROMs) after multilevel anterior versus posterior cervical fusion., Methods: Adult patients who underwent anterior or posterior cervical fusion at three or more levels between 2014 and 2020 were analyzed. Each group was subdivided based on the occurrence and severity of perioperative complication: no complication versus minor complication versus major complication. The study primarily compared PROMs and minimal clinically important differences (MCIDs) within and between the groups., Results: A total of 146 anterior (102 with no complications, 36 with minor complications, 8 with major complications) and 55 posterior (36 with no complications, 13 with minor complications, 6 with major complications) cervical fusion cases were analyzed. Within the anterior or posterior group, there were no significant differences in the PROM change or proportions of patients achieving the MCID. In comparing the anterior group with the posterior group, anterior patients without complications had better improvement in the 3-month Neck Disability Index (coefficient 11.2, p = 0.019), with higher odds of achieving the MCID for the modified Japanese Orthopaedic Association score at 3 months (OR 2.0, p = 0.039). Otherwise, there were no significant differences in the PROM change or proportions of patients achieving the MCID in subsets of anterior or posterior patients with minor or major complications. Furthermore, patients with major complications had higher early readmission rates regardless of the surgical approach. Major complications were also associated with longer and increased rates of intensive care unit stays after posterior fusion compared with anterior fusion., Conclusions: This study suggests that the severity of perioperative complications following anterior or posterior cervical fusion did not predict changes in PROMs or achievement of MCIDs in the anterior or posterior group. Also, PROMs may not fully differentiate the full extent of the impact of perioperative complications following anterior versus posterior cervical fusion. Otherwise, in subsets of patients without complications, anterior compared with posterior patients had improved Neck Disability Index scores at 3 months, with a significant proportion of patients achieving the MCID for the modified Japanese Orthopaedic Association score at 3 months.

Study Design: Retrospective analysis of prospective multicenter adult spinal deformity (ASD) database., Objective: To determine the prevalence and prognosis of postoperative coronal malalignment following LLIF for ASD with Qiu type A coronal alignment., Summary of Background Data: Qiu Type A coronal alignment is defined as coronal vertical axis (CVA) <30mm.1 There is concern that circumferential minimally invasive surgery (cMIS) with lateral lumbar interbody fusion (LLIF) is associated with postoperative coronal malalignment in ASD with preoperative Qiu type A patients., Methods: Qui type A patients undergoing cMIS with LLIF for ASD were included, with ASD defined with at least: maximum CC≥20°, SVA>5 cm, PI-LL≥10°, or PT>20°. Two year (2Y) clinical outcomes were compared for type A with 2Y CVA≥30 mm (MAL) versus <30 mm (ALIGN) and were adjusted for factors reaching P<0.05 on univariate comparisons (age, BMI, and ODI)., Results: 43 patients met inclusion criteria, of which 12 (27.9%) developed coronal malalignment and 31 (72.1%) remained coronally aligned at 2Y. At baseline, MAL were older (73.0 vs. 69.0, P=0.045), had a lower BMI (26.09 vs. 29.45, P=0.047), and were less disabled (ODI 42.83 vs. 51.69, P=0.016). Otherwise, the groups were well-matched for baseline characteristics. At 2Y, MAL had a greater 2Y SVA (mean 54.08 vs 19.00 mm, P=0.01). Clinically, MAL was associated with inferior 2Y SF-36 PCS (34.78 vs. 37.42, adj P=0.043) and 2Y SRS-22r function/activity domain (3.03 vs. 3.36, adj P=0.040), but otherwise similar in other patient-reported-outcome-metrics (adj P>0.05 for all). 2Y complications were similar between groups, including for reoperations and major and minor complications (adj P>0.05 for all)., Conclusions: In Qui type A patients undergoing cMIS with LLIF for ASD, 27.9% develop coronal malalignment, which was associated with worse SF-36 PCS and SRS-22r function/activity. Despite radiographic malalignment, malalignment was not associated with higher 2-year complication rates including reoperations., Competing Interests: There is no conflict of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background and Objectives: We sought to compare long-term clinical and radiographic outcomes in patients who underwent staged vs same-day circumferential minimally invasive surgery (cMIS) for adult spinal deformity (ASD)., Methods: We reviewed staged and same-day cMIS ASD cases in a prospective multi-institution database to compare preoperative and 2-year clinical and radiographic parameters between cohorts., Results: A total of 85 patients with a 2-year follow-up were identified (27 staged, 58 same-day). Staged patients had more extensive surgeries and greater hospital length of stay (all P < .001). There were no significant differences in preoperative or 2-year postoperative clinical metrics between cohorts. Patients in the staged cohort also had greater preoperative coronal deformity and thus experienced greater reduction in coronal deformity at 2 years (all P < .01)., Conclusion: Patients undergoing staged or same-day cMIS correction had similar outcomes at 2 years postoperatively. Staged cMIS ASD correction may be more appropriate in patients with greater deformity, higher frailty, and who require longer, more extensive surgeries., (Copyright © Congress of Neurological Surgeons 2024. All rights reserved.)

Introduction: Central neuropathic pain (CNP) commonly develops in patients after spinal cord injury (SCI), causing debilitating symptoms and sensory abnormalities to mechanical and thermal stimuli. The biological variability of pain phenotypes in individuals has limited the number of positive outcomes. Thus, it is necessary to investigate the physiological processes contributing to sensory changes that develop over time., Objective: To investigate the physiological processes contributing to neuropathic pain sensory changes and locomotor impairments with sensory phenotypes that develop over time., Methods: Using the tail flick and von Frey tests, we performed hierarchical clustering to determine the subpopulation of rats that developed thermal and mechanical sensory abnormalities. To measure inflammation as a potential mediator of CNP phenotypes, we used flow cytometry and immunohistochemistry. Finally, to assess the secondary effects on locomotor recovery, up to 8 weeks after injury, we used the CatWalk test to assess multiple parameters of gait., Results: The von Frey test showed a subpopulation of SCI rats that were hyposensitive to mechanical stimuli from 6 to 8 weeks after injury. The tail flick test showed a subpopulation of SCI rats that were hypersensitive to thermal stimuli at 1 week and 3 to 8 weeks after injury. Although there were no differences in inflammatory cells between subpopulations, we did see significant changes in locomotor recovery between rats with and without sensory abnormalities., Conclusion: The myeloid cell population at large is not affected by mechanical or thermal phenotypes of pain in this model; however, locomotor recovery is impaired depending on the pain phenotype present. Further investigation into acute inflammatory cells may be insightful for predicting the development of pain phenotypes., Competing Interests: The authors have no conflict of interest to declare., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The International Association for the Study of Pain.)

Objective: This study evaluates the impact of L4-L5 minimally invasive surgery (MIS)- transforaminal lumbar interbody fusion (TLIF) on adjacent-level parameters., Methods: This is a retrospective study performed on consecutive patients between January 2015 and December 2019. The index- and adjacent-level segmental lordosis (SL) and disc angle (DA) were measured. Patient-reported outcomes (PROs) were collected preoperatively and at 3-24 months postoperatively. Factors influencing changes in adjacent-level parameters and the occurrence of adjacent segment degeneration (ASDeg) were assessed., Results: A total of 117 adult patients, averaging 65.5 years of age and slight preponderance of female (56.4%), were analyzed. L4-L5 SL decreased at 2 years (P < 0.05), but L4-L5 DA significantly increased at all timepoints (P < 0.05). While L3-L4 SL and DA significantly decreased at all timepoints (P < 0.05), L5-S1 SL decreased at 3 and 12 months (P < 0.05) and L5-S1 DA only significantly decreased at 2 years (P < 0.05). All PROs improved significantly (P < 0.0001). The ASDeg rate was 19.7% at 2.2 years. Cephalad and caudal ASDeg rates were 12.0% and 10.3%, respectively. Eight patients (6.8%) required adjacent-level reoperations, mainly at L3-L4 (6 cases). The use of expandable cage significantly reduced the odds of caudal ASDeg (OR 0.15, P = 0.037), but had no significant effect on cephalad ASDeg., Conclusions: L4-L5 MIS-TLIF had a more consistent effect on L3-L4 than L5-S1. Although adjacent-level SL and DA decreased over time, their association with ASDeg appears limited, suggesting a multifactorial etiology. L4-L5 MIS-TLIF provides demonstrable clinical benefits with lasting PRO improvements and low adjacent-level reoperations., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Purpose: To assess impact of baseline disability on HRQL outcomes., Methods: CD patients with baseline (BL) and 2 year (2Y) data included, and ranked into quartiles by baseline NDI, from lowest/best score (Q1) to highest/worst score (Q4). Means comparison tests analyzed differences between quartiles. ANCOVA and logistic regressions assessed differences in outcomes while accounting for covariates (BL deformity, comorbidities, HRQLs, surgical details and complications)., Results: One hundred and sixteen patients met inclusion (Age:60.97 ± 10.45 years, BMI: 28.73 ± 7.59 kg/m 2 , CCI: 0.94 ± 1.31). The cohort mean cSVA was 38.54 ± 19.43 mm and TS-CL: 37.34 ± 19.73. Mean BL NDI by quartile was: Q1: 25.04 ± 8.19, Q2: 41.61 ± 2.77, Q3: 53.31 ± 4.32, and Q4: 69.52 ± 8.35. Q2 demonstrated greatest improvement in NRS Neck at 2Y (-3.93), compared to Q3 (-1.61, p = .032) and Q4 (-1.41, p = .015). Q2 demonstrated greater improvement in NRS Back (-1.71), compared to Q4 (+ 0.84, p = .010). Q2 met MCID in NRS Neck at the highest rates (69.9%), especially compared to Q4 (30.3%), p = .039. Q2 had the greatest improvement in EQ-5D (+ 0.082), compared to Q1 (+ 0.073), Q3 (+ 0.022), and Q4 (+ 0.014), p = .034. Q2 also had the greatest mJOA improvement (+ 1.517), p = .042., Conclusions: Patients in Q2, with mean BL NDI of 42, consistently demonstrated the greatest improvement in HRQLs whereas those in Q4, (NDI 70), saw the least. BL NDI between 39 and 44 may represent a disability "Sweet Spot," within which operative intervention maximizes patient-reported outcomes. Furthermore, delaying intervention until patients are severely disabled, beyond an NDI of 61, may limit the benefits of surgery., (© 2024. The Author(s), under exclusive licence to Scoliosis Research Society.)

Background: Severe sagittal plane deformity with loss of L4-S1 lordosis is disabling and can be improved through various surgical techniques. However, data are limited on the differing ability of anterior lumbar interbody fusion (ALIF), pedicle subtraction osteotomy (PSO), and transforaminal lumbar interbody fusion (TLIF) to achieve alignment goals in severely malaligned patients., Methods: Severe adult spinal deformity patients with preoperative PI-LL >20°, L4-S1 lordosis <30°, and full body radiographs and PROMs at baseline and 6-week postoperative visit were included. Patients were grouped into ALIF (1-2 level ALIF at L4-S1), PSO (L4/L5 PSO), and TLIF (1-2 level TLIF at L4-S1). Comparative analyses were performed on demographics, radiographic spinopelvic parameters, complications, and PROMs., Results: Among the 96 included patients, 40 underwent ALIF, 27 underwent PSO, and 29 underwent TLIF. At baseline, cohorts had comparable age, sex, race, Edmonton frailty scores, and radiographic spinopelvic parameters (P > 0.05). However, PSO was performed more often in revision cases (P < 0.001). Following surgery, L4-S1 lordosis correction (P = 0.001) was comparable among ALIF and PSO patients and caudal lordotic apex migration (P = 0.044) was highest among ALIF patients. PSO patients had higher intraoperative estimated blood loss (P < 0.001) and motor deficits (P = 0.049), and in-hospital ICU admission (P = 0.022) and blood products given (P = 0.004), but were otherwise comparable in terms of length of stay, blood transfusion given, and postoperative admission to rehab. Likewise, 90-day postoperative complication profiles and 6-week PROMs were comparable as well., Conclusions: ALIF can restore L4-S1 sagittal alignment as powerfully as PSO, with fewer intraoperative and in-hospital complications. When feasible, ALIF is a suitable alternative to PSO and likely superior to TLIF for correcting L4-S1 lordosis among patients with severe sagittal malalignment., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Minimally invasive spinal surgery has shown benefits not only from a clinical standpoint but also in some cost-effectiveness metrics. Microendoscopic procedures combine optical advantages of endoscopy with the preservation of bimanual surgical maneuvers that are not feasible with full percutaneous endoscopic procedures. TELIGEN is a new endoscopic platform designed to optimize these operations. Our aim was to present a retrospective review of surgical data from the first consecutive cases applying this device in our institution and describe some of its technical details. 25 patients have underwent procedures using this device at our institution to the date, with a mean follow-up of 341.7 ± 45.1 days. 17 decompression-only procedures, including microendoscopic discectomies (MED) and decompression of stenosis (MEDS), with or without foraminotomies (± MEF) and 8 microendoscopic transforaminal lumbar interbody fusions (ME-TLIF) were performed. Mean age and body mass index (BMI) were respectively 58.8 ± 17.4 years and 27.6 ± 5.3 kg/m 2 . Estimated blood loss (13 ± 4.8, 12.8 ± 6.98 and 76.3 ± 35.02 mL), postoperative length of hospital stay (11.2 ± 21.74, 22.1 ± 26.85 and 80.7 ± 44.60 h), operative time (130.3 ± 58.53, 121 ± 33.90 and 241.5 ± 45.27 min) and cumulative intraprocedural radiation dose (14.2 ± 6.36, 15.4 ± 12.17 and 72.8 ± 12.26 mGy) are reported in this paper for MED ± MEF, MEDS ± MEF and ME-TLIF, respectively. TELIGEN affords an expanded surgical field of view with unique engineered benefits that provide a promissing platform to enhance minimally invasive spine surgery., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Study Design: Retrospective review of prospectively collected data., Objective: To investigate the effect of lower extremity osteoarthritis on sagittal alignment and compensatory mechanisms in adult spinal deformity (ASD)., Background: Spine, hip, and knee pathologies often overlap in ASD patients. Limited data exists on how lower extremity osteoarthritis impacts sagittal alignment and compensatory mechanisms in ASD., Patients and Methods: In total, 527 preoperative ASD patients with full body radiographs were included. Patients were grouped by Kellgren-Lawrence grade of bilateral hips and knees and stratified by quartile of T1-Pelvic Angle (T1PA) severity into low-, mid-, high-, and severe-T1PA. Full-body alignment and compensation were compared across quartiles. Regression analysis examined the incremental impact of hip and knee osteoarthritis severity on compensation., Results: The mean T1PA for low-, mid-, high-, and severe-T1PA groups was 7.3°, 19.5°, 27.8°, and 41.6°, respectively. Mid-T1PA patients with severe hip osteoarthritis had an increased sagittal vertical axis and global sagittal alignment ( P <0.001). Increasing hip osteoarthritis severity resulted in decreased pelvic tilt ( P =0.001) and sacrofemoral angle ( P <0.001), but increased knee flexion ( P =0.012). Regression analysis revealed that with increasing T1PA, pelvic tilt correlated inversely with hip osteoarthritis and positively with knee osteoarthritis ( r2 =0.812). Hip osteoarthritis decreased compensation through sacrofemoral angle (β-coefficient=-0.206). Knee and hip osteoarthritis contributed to greater knee flexion (β-coefficients=0.215, 0.101; respectively). For pelvic shift, only hip osteoarthritis significantly contributed to the model (β-coefficient=0.100)., Conclusions: For the same magnitude of spinal deformity, increased hip osteoarthritis severity was associated with worse truncal and full body alignment with posterior translation of the pelvis. Patients with severe hip and knee osteoarthritis exhibited decreased hip extension and pelvic tilt but increased knee flexion. This examines sagittal alignment and compensation in ASD patients with hip and knee arthritis and may help delineate whether hip and knee flexion is due to spinal deformity compensation or lower extremity osteoarthritis., Competing Interests: The International Spine Study Group reports the following: grants to the foundation from Medtronic, Globus, Stryker, SI Bone, Carlsmed. The remaining authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background and Objectives: Studies have demonstrated increased risk of adjacent segment disease (ASD) after open fusion with adjacent-level laminectomy, with rates ranging from 16%-47%, potentially related to disruption of the posterior ligamentous complex. Minimally invasive surgical (MIS) approaches may offer a more durable result. We report institutional outcomes of simultaneous MIS transforaminal lumbar interbody fusion (MISTLIF) and adjacent-level laminectomy for patients with low grade spondylolisthesis and ASD., Methods: Retrospective analysis was performed on patients who underwent MISTLIF with adjacent level laminectomy to treat grade I-II spondylolisthesis with adjacent stenosis at a single institution from 2007-2022., Results: A total of 34 patients met criteria, with mean follow-up of 23.1 months. In total, 37 levels were fused and 45 laminectomies performed. In this group, 21 patients received a single level laminectomy and single-level MISTLIF, 10 patients received a 2-level laminectomy and single-level MISTLIF, 2 patients received a single-level laminectomy and 2-level MISTLIF, and 1 patient received a 2-level laminectomy and 2-level MISTLIF. Three (8.8%) patients experienced clinically significant postoperative ASD requiring reoperation. Three other patients required reoperation for other reasons. Multiple logistic regression did not reveal any association between development of ASD and surgical covariates., Conclusion: MISTLIF with adjacent-level laminectomy demonstrated a favorable safety profile with rates of postoperative ASD lower than published rates after open fusion and on par with the published rates of ASD from MISTLIF alone. Future prospective studies may better elucidate the durability of adjacent-level laminectomies when performed alongside MISTLIF, but retrospective data suggests it is safe and durable., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Study Design: Retrospective review of prospectively collected data., Objective: To analyze the impact of operative room (OR) time in adult spinal deformity (ASD) surgery on patient outcomes., Background: It is currently unknown if OR time in ASD patients matched for deformity severity and surgical invasiveness is associated with patient outcomes., Materials and Methods: ASD patients with baseline and two-year postoperative radiographic and patient-reported outcome measures (PROM) data, undergoing a posterior-only approach for long fusion (>L1-Ilium) were included. Patients were grouped into short OR time (<40th percentile: <359 min) and long OR time (>60th percentile: >421 min). Groups were matched by age, baseline deformity severity, and surgical invasiveness. Demographics, radiographic, PROM data, fusion rate, and complications were compared between groups at baseline and two years follow-up., Results: In total, 270 patients were included for analysis: the mean OR time was 286 minutes in the short OR group versus 510 minutes in the long OR group ( P <0.001). Age, gender, percent of revision cases, surgical invasiveness, pelvic incidence minus lumbar lordosis, sagittal vertical axis, and pelvic tilt were comparable between groups ( P >0.05). Short OR had a slightly lower body mass index than the short OR group ( P <0.001) and decompression was more prevalent in the long OR time ( P =0.042). Patients in the long group had greater hospital length of stay ( P =0.02); blood loss ( P <0.001); proportion requiring intensive care unit ( P =0.003); higher minor complication rate ( P =0.001); with no significant differences for major complications or revision procedures ( P >0.5). Both groups had comparable radiographic fusion rates ( P =0.152) and achieved improvement in sagittal alignment measures, Oswestry disability index, and Short Form-36 ( P <0.001)., Conclusion: Shorter OR time for ASD correction is associated with a lower minor complication rate, a lower estimated blood loss, fewer intensive care unit admissions, and a shorter hospital length of stay without sacrificing alignment correction or PROMs. Maximizing operative efficiency by minimizing OR time in ASD surgery has the potential to benefit patients, surgeons, and hospital systems., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: Depression has been implicated with worse immediate postoperative outcomes in adult spinal deformity (ASD) correction, yet the specific impact of depression on those patients undergoing minimally invasive surgery (MIS) requires further clarity. This study aimed to evaluate the role of depression in the recovery of patients with ASD after undergoing MIS., Methods: Patients who underwent MIS for ASD with a minimum postoperative follow-up of 1 year were included from a prospectively collected, multicenter registry. Two cohorts of patients were identified that consisted of either those affirming or denying depression on preoperative assessment. The patient-reported outcome measures (PROMs) compared included scores on the Oswestry Disability Index (ODI), numeric rating scale (NRS) for back and leg pain, Scoliosis Research Society Outcomes Questionnaire (SRS-22), SF-36 physical component summary, SF-36 mental component summary (MCS), EQ-5D, and EQ-5D visual analog scale., Results: Twenty-seven of 147 (18.4%) patients screened positive for preoperative depression. The nondepressed cohort had an average of 4.83 levels fused, and the depressed cohort had 5.56 levels fused per patient (p = 0.267). At 1-year follow-up, 10 patients still reported depression, representing a 63% decrease. Postoperatively, both cohorts demonstrated improvement in their PROMs; however, at 1-year follow-up, those without depression had statistically better outcomes based on the EQ-5D, MCS, and SRS-22 scores (p < 0.05). Patients with depression continued to experience higher NRS leg scores at 1-year follow-up (3.63 vs 2.22, p = 0.018). After controlling for covariates, the authors found that depression significantly impacted only 1-year follow-up MCS scores (β = 8.490, p < 0.05)., Conclusions: Depressed and nondepressed patients reported similar improvements after MIS surgery, except MCS scores were more likely to improve in nondepressed patients.

Purpose: In this study the authors compare the radiographic findings of patients undergoing 1-3 level ACDF a rigid CFRP plate and a translational titanium plate system with a focus on radiographic alignment., Material and Methods: A retrospective review 70 consecutive patients undergoing a 1 to 3 level ACDF for cervical spondylosis was conducted. 2 groups depending on the cervical plating system were created including 38 patients in group 1 (dynamic plate) and 32 in group 2 (rigid CFRP plate). Plain neutral radiographs preoperatively, immediately after surgery and at most recent follow-up were used to assess parameters on sagittal alignment, fusion height, adjacent segment ossification (ASO), fusion rate and implant failure., Results: There were no significant differences between groups preoperatively. Both groups had a more than 12 months follow-up ( p  = 0.327). Improvement of C2-7 lordosis was seen in both groups but only in group 1 it reached statistical significance at final follow-up. Significant improvement in sagittal segmental alignment was noted in both groups following surgery. A significant sagittal correction of 5.5 ± 9.1 degrees ( p  = 0.002) was maintained through follow-up only in group 2. No significantly different was seen for segmental fusion rates and loss of fusion height. There were no instances of implant failure within both groups. Worsening of ASO was 20% for both groups., Conclusion: ACDF allows for correction and maintenance of cervical alignment. Rigid rigid plate appears more effective at maintaining segmental lordotic correction. The fusion rate and implant failure was not different for both groups.

Objective: Patients with degenerative lumbar scoliosis (DLS) and neurogenic pain may be candidates for decompression alone or short-segment fusion. In this study, minimally invasive surgery (MIS) decompression (MIS-D) and MIS short-segment fusion (MIS-SF) in patients with DLS were compared in a propensity score-matched analysis., Methods: The propensity score was calculated using 13 variables: sex, age, BMI, Charlson Comorbidity Index, smoking status, leg pain, back pain, grade 1 spondylolisthesis, lateral spondylolisthesis, multilevel spondylolisthesis, lumbar Cobb angle, pelvic incidence minus lumbar lordosis, and pelvic tilt in a logistic regression model. One-to-one matching was performed to compare perioperative morbidity and patient-reported outcome measures (PROMs). The minimal clinically important difference (MCID) for patients was calculated based on cutoffs of percentage change from baseline: 42.4% for Oswestry Disability Index (ODI), 25.0% for visual analog scale (VAS) low-back pain, and 55.6% for VAS leg pain., Results: A total of 113 patients were included in the propensity score calculation, resulting in 31 matched pairs. Perioperative morbidity was significantly reduced for the MIS-D group, including shorter operative duration (91 vs 204 minutes, p < 0.0001), decreased blood loss (22 vs 116 mL, p = 0.0005), and reduced length of stay (2.6 vs 5.1 days, p = 0.0004). Discharge status (home vs rehabilitation), complications, and reoperation rates were similar. Preoperative PROMs were similar, but after 3 months, improvement was significantly higher for the MIS-SF group in the VAS back pain score (-3.4 vs -1.2, p = 0.044) and Veterans RAND 12-Item Health Survey (VR-12) Mental Component Summary (MCS) score (+10.3 vs +1.9, p = 0.009), and after 1 year the MIS-SF group continued to have significantly greater improvement in the VAS back pain score (-3.9 vs -1.2, p = 0.026), ODI score (-23.1 vs -7.4, p = 0.037), 12-Item Short-Form Health Survey MCS score (+6.5 vs -6.5, p = 0.0374), and VR-12 MCS score (+7.6 vs -5.1, p = 0.047). MCID did not differ significantly between the matched groups for VAS back pain, VAS leg pain, or ODI scores (p = 0.38, 0.055, and 0.072, respectively)., Conclusions: Patients with DLS undergoing surgery had similar rates of significant improvement after both MIS-D and MIS-SF. For matched patients, tradeoffs were seen for reduced perioperative morbidity for MIS-D versus greater magnitudes of improvement in back pain, disability, and mental health for patients 1 year after MIS-SF. However, rates of MCID were similar, and the small sample size among the matched patients may be subject to patient outliers, limiting generalizability of these results.

Spinal cord injury (SCI) affects ∼1,300,000 people living in the United States. Most research efforts have been focused on reversing paralysis, as this is arguably the most defining feature of SCI. The damage caused by SCI, however, extends past paralysis and includes other debilitating outcomes including immune dysfunction and gut dysbiosis. Recent efforts are now investigating the pathophysiology of and developing therapies for these more distal manifestations of SCI. One exciting avenue is the spinal cord-gut-immune axis, which proposes that gut dysbiosis amplifies lesion inflammation and impairs SCI recovery. This review will highlight the most recent findings regarding gut and immune dysfunction following SCI, and discuss how the central nervous system (CNS), gut, and immune system all coalesce to form a bidirectional axis that can impact SCI recovery. Finally, important considerations regarding how the spinal cord-gut-immune axis fits within the larger framework of therapeutic development (i.e., probiotics, fecal transplants, dietary modifications) will be discussed, emphasizing the lack of interdepartmental investigation and the missed opportunity to maximize therapeutic benefit in SCI.

Background: We developed a spinal deformity complexity checklist (SDCC) to assess the difficulty in performing a circumferential minimally invasive surgery (MIS) for adult spinal deformity., Methods: A modified Delphi method of panel experts was used to construct an SDCC checklist of radiographic and patient-related characteristics that could affect the complexity of surgery via MIS approaches. Ten surgeons with expertise in MIS deformity surgery were queried to develop and refine the SDCC with 3 radiographic categories (x-ray, magnetic resonance imaging, computed tomography) and 1 patient-related category. Within each category, characteristics affecting MIS complexity were identified by initial roundtable discussion. Second-round discussion determined which characteristics substantially impacted complexity the most., Results: Thirteen characteristics within the x-ray category were determined. Spinopelvic characteristics, endpoints of instrumentation, and prior hardware/fusion were associated with increased complexity. Vertebral body rotation-as reflected by the Nash-Moe grade-added significant complexity. Psoas anatomy and spinal stenosis added the most complexity for the 5 magnetic resonance imaging characteristics. There were 3 characteristics in the CT category with pre-exisiting fusion, being the variable most highly selected. Of the 5 patient-related characteristics, osteoporosis and BMI were found to most affect complexity., Conclusions: The SDCC is a comprehensive list of pertinent radiographic and patient-related characteristics affecting complexity level for MIS deformity surgery. The value of the SDCC is that it allows rapid assessment of key factors when determining whether MIS surgery can be performed effectively and safely. Patients with scores of 4 in any characteristic should be considered challenging to treat with MIS; open surgery may be a better alternative., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: Circumferential minimally invasive surgery (cMIS) may provide incremental benefits compared with open surgery for patients with increasing frailty status by decreasing peri- and postoperative complications., Methods: Operative patients with adult spinal deformity (ASD) ≥ 18 years old with baseline and 2-year postoperative data were assessed. With propensity score matching, patients who underwent cMIS (cMIS group) were matched with similar patients who underwent open surgery (open group) based on baseline BMI, C7-S1 sagittal vertical axis, pelvic incidence to lumbar lordosis mismatch, and S1 pelvic tilt. The Passias modified ASD frailty index (mASD-FI) was used to determine patient frailty stratification as not frail, frail, or severely frail. Baseline and postoperative factors were assessed using two-way analysis of covariance (ANCOVA) and multivariate ANCOVA while controlling for baseline age, Charlson Comorbidity Index (CCI) score, and number of levels fused., Results: After propensity score matching, 170 ASD patients (mean age 62.71 ± 13.64 years, 75.0% female, mean BMI 29.25 ± 6.60 kg/m2) were included, split evenly between the cMIS and open groups. Surgically, patients in the open group had higher numbers of posterior levels fused (p = 0.021) and were more likely to undergo three-column osteotomies (p > 0.05). Perioperatively, cMIS patients had lower intraoperative blood loss and decreased use of cell saver across frailty groups (with adjustment for baseline age, CCI score, and levels fused), as well as fewer perioperative complications (p < 0.001). Adjusted analysis also revealed that compared to open patients, increasingly frail patients in the cMIS group were also more likely to demonstrate greater improvement in 1- and 2-year postoperative scores for the Oswestry Disability Index, SRS-36 (total), EQ-5D and SF-36 (all p < 0.05). With regard to postoperative complications, increasingly frail patients in the cMIS group were also noted to experience significantly fewer complications overall (p = 0.036) and fewer major intraoperative complications (p = 0.039). The cMIS patients were also less likely to need a reoperation than their open group counterparts (p = 0.043)., Conclusions: Surgery performed with a cMIS technique may offer acceptable outcomes, with diminishment of perioperative complications and mitigation of catastrophic outcomes, in increasingly frail patients who may not be candidates for surgery using traditional open techniques. However, further studies should be performed to investigate the long-term impact of less optimal alignment in this population.

Study Design: Systematic review and meta-analysis.OBJECTIVESSurgical decompression alone for patients with neurogenic leg pain in the setting of degenerative lumbar scoliosis (DLS) and stenosis is commonly performed, however, there is no summary of evidence for outcomes., Methods: A systematic search of English language medical literature databases was performed for studies describing outcomes of decompression alone in DLS, defined as Cobb angle >10˚, and 2-year minimum follow-up. Three outcomes were examined: 1) Cobb angle progression, 2) reoperation rate, and 3) ODI and overall satisfaction. Data were pooled and weighted averages were calculated to summarize available evidence., Results: Across 15 studies included in the final analysis, 586 patients were examined. Average preoperative and postoperative Cobb angles were 17.6˚ (Range: 12.7 - 25˚) and 18.0 (range 14.1 - 25˚), respectively. Average change in Cobb angle was an increase of 1.8˚. Overall rate of reoperation ranged from 3 to 33% with an average of 9.7%. Average ODI before surgery, after surgery, and change in scores were 56.4%, 27.2%, and an improvement of 29% respectively. Average from 8 studies that reported patient satisfaction was 71.2%., Conclusions: Current literature on decompression alone in the setting of DLS is sparse and is not high quality, limited to patients with small magnitude of lumbar coronal Cobb angle, and heterogenous in the type of procedure performed. Based on available evidence, select patients with DLS who undergo decompression alone had minimal progression of Cobb angle, relatively low reoperation rate, and favorable patient-reported outcomes.

Study Design: Systematic review and meta-analysis., Objectives: Patients with lateral cervical disc and foraminal pathology can be treated with anterior and posterior approaches including anterior cervical discectomy and fusion(ACDF), cervical total disc arthroplasty(TDA), and minimally invasive posterior cervical foraminotomy(MIS-PCF). Although MIS-PCF may have some advantages over the anterior approaches, few comparative studies and meta-analyses have been done to assess superiority., Methods: This study includes a systematic review of the literature and meta-analysis of studies directly comparing minimally invasive posterior cervical foraminotomy to either anterior cervical discectomy and fusion or cervical total disc arthroplasty., Results: In comparing patients undergoing ACDF and MIS-PCF, operative time ranged from 68 to 97.8 minutes in the ACDF group compared to 28 to 93.9 minutes in the MIS-PCF group. Mean postoperative length of stay ranged from 33.84 to 112.8 hours in the ACDF group compared to 13.68 to 83.6 hours in the MIS-PCF group. The total complication rates were 3.72% in the ACDF group and 3.73% in the MIS-PCF group. A random-effects model meta-analysis was carried out which failed to show a statistically significant difference in the complication rate between the two procedures(OR .91; 95% CI 0.13, 6.43; P = .92, I 2 = 59%). The total reoperation rate was 3.5% in the ACDF group and 5.4% in the MIS-PCF group. A random-effects model meta-analysis was carried out which failed to show a statistically significant difference in the reoperation rate between the two procedures(OR .66; 95% CI 0.33, 1.33; P = .25, I 2 = 0). In comparing patients undergoing TDA and MIS-PCF, operative time ranged from 90.3 to 106.7 minutes in the TDA group compared to 77.4 to 93.9 minutes in the MIS-PCF group. Mean postoperative length of stay ranged from 103.2 to 165.6 hours in the TDA group and 93.6 to 98.4 hours in the MIS-PCF group. The complication rate ranged from 23.5 to 28.6% in the TDA group and 0 to 14.3% in the MIS-PCF group. The overall reoperation rates were 2.6% in the TDA group and 10.2% in the MIS-PCF group., Conclusions: There is no clear superiority between MIS-PCF and ACDF/TDA in terms of operative time, postoperative length of stay, or rate of complications/reoperations. Further studies with increased follow-up intervals >48 months, and higher sample sizes are necessary to determine the true superiority of MIS-PCF and anterior neck approaches in treatment of lateral disc and foraminal pathology.

Objective: This study assesses cervical alignments after 2-level cervical disc arthroplasty (CDA) versus anterior cervical discectomy and fusion (ACDF) with anterior plate fixation., Methods: Eighty-two patients who underwent 2-level CDA or ACDF in 2014-2019 were identified. Cervical alignment parameters were compared between the 2 cohorts. Subgroup analyses were performed to determine factors that differentiate alignment outcomes between the 2 procedures., Results: Although both cohorts achieved significant focal lordosis (FL) and overall cervical lordotic (CL) gains, CDA cohorts achieved significantly greater 12-month FL gain (P = 0.022). However, in a multivariate analysis controlling for preoperative variables, FL gain was no longer significant. Although the CDA cervical sagittal vertical axis (cSVA) significantly improved at 3 (P = 0.030) and 12 (P = 0.007) months, these improvements were not superior to the ACDF cSVA. Male patients undergoing CDA achieved greater 12-month CL gain. Patients undergoing CDA with body mass index >25 kg/m 2 achieved greater 12-month FL gain. Patients undergoing CDA with symptom duration >12 months achieved greater FL gain at 3 and 12 months. Patients undergoing CDA with high baseline T1 slope or cSVA achieved greater 12-month cSVA reduction. Clinical outcomes were comparable between the 2 cohorts. Unlike the ACDF group, CL gain in the CDA group was significantly correlated with the cSVA reduction, which was associated with significant improvement in the Neck Disability Index, arm pain, and 12-Item Short-Form Mental Component Scores. Heterotopic ossification was not found to significantly affect patient outcome and cervical alignment in both cohorts., Conclusions: ACDF and CDA are viable options for 2-level degenerative disc disease in carefully selected patients. Both approaches produced equivalent postoperative alignment changes in a 2-level operation., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objective: The primary objective of this study was to evaluate the safety of 3 escalating doses of oligodendrocyte progenitor cells (LCTOPC1; previously known as GRNOPC1 and AST-OPC1) administered at a single time point between 21 and 42 days postinjury to participants with subacute cervical spinal cord injuries (SCIs). The secondary objective was to evaluate changes in neurological function following administration of LCTOPC1., Methods: This study was designed as an open-label, dose-escalation, multicenter clinical trial. Twenty-five participants with C4-7 American Spinal Injury Association Impairment Scale grade A or B injuries received a single dose of either 2 × 106, 1 × 107, or 2 × 107 LCTOPC1 delivered via intraparenchymal injection into the spinal cord at the site of injury using a custom-designed syringe positioning device. Low-dose tacrolimus was administered until day 60. Outcome measures included adverse event (AE) monitoring and neurological function as measured by the International Standards for Neurological Classification of Spinal Cord Injury., Results: All 25 participants experienced at least one AE, with a total of 534 AEs (32 study-related vs 502 study-unrelated anticipated complications of SCI) reported at the completion of 1-year follow-up. There were 29 serious AEs reported. Two grade 3 serious AEs (CSF leak in one participant and a bacterial infection in another) were considered related to the injection procedure and to immunosuppression with tacrolimus, respectively. The CSF leakage resolved with sequelae, including self-limited altered mental status, and the infection resolved with antibiotic therapy. For all participants, MRI scans demonstrated no evidence of an enlarging mass, spinal cord damage related to the injection procedure, inflammatory lesions in the spinal cord, or masses in the ventricular system. At 1-year follow-up, 21/22 (96%) of the intention-to-treat group recovered one or more levels of neurological function on at least one side of their body, and 7/22 (32%) recovered two or more levels of neurological function on at least one side of their body., Conclusions: LCTOPC1 can be safely administered to participants in the subacute period after cervical SCI. The injection procedure, low-dose temporary immunosuppression regimen, and LCTOPC1 were well tolerated. The safety and neurological function data support further investigation to determine the efficacy of LCTOPC1 in the treatment of SCI. Clinical trial registration no.: NCT02302157 (ClinicalTrials.gov).

Background and Objectives : The use of minimally invasive retractor systems has significantly decreased the amount of tissue dissection and blood loss, and the duration of post-operative recovery after far-lateral disc herniations (FLDH). In this technical note, the technique of docking the tubular retractor on the caudal transverse process is described for an efficient approach with a decreased need for manipulation of the exiting nerve root. Materials and Methods : The case reported is that of a woman affected by a right-sided FLDH at the L4-5 level causing an L4 radiculopathy with weakness and numbness. A review of the literature for FLDH regarding the key anatomy used during a far lateral approach was also performed. Results : The patient showed a significant improvement of her dorsiflexion weakness and radiating leg pain at her 2-week and 5-week post-operative visits, and at a 6-month follow-up she had near-complete relief of her symptoms, including resolution of foot numbness. Prior techniques for tubular microdiscectomy for FLDH report docking on the facet joint, pars interarticularis, and the cranial transverse process. Conclusions : This technical note details that the utility of docking a tubular retractor at the caudal transverse process improves upon already established techniques for minimally invasive tubular discectomy for FLDH.

Background: Symptomatic spinal epidural veins (SEV) are a rare cause of neurologic dysfunction. Treatment is centered upon addressing the underlying venous pathology to relieve mechanical compression of the neurologic structures. However, open surgical ligation is often associated with considerable blood loss., Objective: We discuss a unique case of a large symptomatic epidural venous varix and potential treatment strategy., Methods and Materials: A 15-year-old female presented with a 1-year history of left L5 radicular pain and weakness. Lumbar MRI demonstrated a central L5/S1 herniated disc and a large extradural anomalous SEV compressing the exiting left L5 nerve root at the L5/S1 neuroformina. The SEV was treated using a transvenous liquid embolic agent providing symptomatic relief. At 16-months follow-up, she reported recurrent symptoms. She ultimately underwent a left L5/S1 MIS decompression without complication., Conclusion: Transvenous liquid embolization of large symptomatic SEV may provide temporary neurologic relief and decrease morbidity associated with open surgical treatment options., Competing Interests: None

Objective: The purpose of this study was to evaluate the safety of oligodendrocyte progenitor cells (LCTOPC1) derived from human pluripotent stem cells administered between 7 and 14 days postinjury to patients with T3 to T11 neurologically complete spinal cord injury (SCI). The rationale for this first-in-human trial was based on evidence that administration of LCTOPC1 supports survival and potential repair of key cellular components and architecture at the SCI site., Methods: This study was a multisite, open-label, single-arm interventional clinical trial. Participants (n = 5) received a single intraparenchymal injection of 2 × 106 LCTOPC1 caudal to the epicenter of injury using a syringe positioning device. Immunosuppression with tacrolimus was administered for a total of 60 days. Participants were followed with annual in-person examinations and MRI for 5 years at the time of this report and will be followed with annual telephone questionnaires for 6 to 15 years postinjection. The primary endpoint was safety, as measured by the frequency and severity of adverse events related to the LCTOPC1 injection, the injection procedure, and/or the concomitant immunosuppression administered. The secondary endpoint was neurological function as measured by sensory scores and lower-extremity motor scores as measured by the International Standards for Neurological Classification of Spinal Cord Injury examinations., Results: No unanticipated serious adverse events related to LCTOPC1 have been reported with 98% follow-up of participants (49 of 50 annual visits) through the first 10 years of the clinical trial. There was no evidence of neurological decline, enlarging masses, further spinal cord damage, or syrinx formation. MRI results during the long-term follow-up period in patients administered LCTOPC1 cells showed that 80% of patients demonstrated T2 signal changes consistent with the formation of a tissue matrix at the injury site., Conclusions: This study provides crucial first-in-human safety data supporting the pursuit of future human embryonic stem cell-derived therapies. While we cannot exclude the possibility of future adverse events, the experience in this trial provides evidence that this cell type can be well tolerated by patients, with an event-free period of up to 10 years. Based on the safety profile of LCTOPC1 obtained in this study, a cervical dose escalation trial was initiated (NCT02302157).

Objective: Expandable transforaminal lumbar interbody fusion (TLIF) cages capable of multidirectional in situ expansion have gained popularity as they increase axial surface area for fusion and may enhance lordotic correction through a traditional minimally invasive surgery (MIS) surgical corridor. We evaluated and compared the radiographic and clinical outcomes between a novel expandable versus static minimally invasive surgery TLIF cage for the treatment of degenerative disk disease., Methods: A single-center retrospective review of 120 consecutive adult patients undergoing 1- or 2-level MIS TLIF with an expandable (n = 60) or static cage was performed between 2015 and 2019. Preoperative and 1-year postoperative radiographic and clinical outcomes were assessed by upright flexion/extension radiographs and serial confidential surveys., Results: One-hundred twenty patients (mean age 63.5 years, 60.0% female) undergoing 1- and 2-level MIS TLIF met inclusion criteria. A statistically significant reduction of spondylolisthesis, restoration of foraminal height as well as anterior and posterior disk height was achieved in both cohorts, however was greater in the expandable cage cohort (ECC) (all P < 0.05). Comparable rates of fusion, 93% and 91%, were observed in the ECC and static cage cohort. A significant reduction in Numeric Pain Rating Scale back and Oswestry Disability Index scores were observed in both cohorts but were more pronounced in the ECC (5.9 ± 2.4 to 2.2 ± 1.9 and 37.3 ± 16.2 to 17.1 ± 15.2) versus static cage cohort (6.2 ± 2.8 to 3.2 ± 2.5 and 41.8 ± 16.1 to 24.3 ± 17.5) (P < 0.05). One instance of cage migration requiring reoperation occurred in the ECC., Conclusions: Taken together, these radiographic and clinical findings suggest an expandable cage placed through an MIS corridor represents a safe, equitable, and efficacious alternative to a static TLIF in adults with degenerative lumbar pathology., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: Minimally invasive surgery (MIS) for adult spinal deformity (ASD) can offer deformity correction with less tissue manipulation and damage. However, the impact of obesity on clinical outcomes and radiographic correction following MIS for ASD is poorly understood. The goal of this study was to determine the role, if any, that obesity has on radiographic correction and health-related quality-of-life measures in MIS for ASD., Methods: Data were collected from a multicenter database of MIS for ASD. This was a retrospective review of a prospectively collected database. Patient inclusion criteria were age ≥ 18 years and coronal Cobb angle ≥ 20°, pelvic incidence-lumbar lordosis mismatch ≥ 10°, or sagittal vertical axis (SVA) > 5 cm. A group of patients with body mass index (BMI) < 30 kg/m2 was the control cohort; BMI ≥ 30 kg/m2 was used to define obesity. Obesity cohorts were categorized into BMI 30-34.99 and BMI ≥ 35. All patients had at least 1 year of follow-up. Preoperative and postoperative health-related quality-of-life measures and radiographic parameters, as well as complications, were compared via statistical analysis., Results: A total of 106 patients were available for analysis (69 control, 17 in the BMI 30-34.99 group, and 20 in the BMI ≥ 35 group). The average BMI was 25.24 kg/m2 for the control group versus 32.46 kg/m2 (p < 0.001) and 39.5 kg/m2 (p < 0.001) for the obese groups. Preoperatively, the BMI 30-34.99 group had significantly more prior spine surgery (70.6% vs 42%, p = 0.04) and worse preoperative numeric rating scale leg scores (7.71 vs 5.08, p = 0.001). Postoperatively, the BMI 30-34.99 cohort had worse Oswestry Disability Index scores (33.86 vs 23.55, p = 0.028), greater improvement in numeric rating scale leg scores (-4.88 vs -2.71, p = 0.012), and worse SVA (51.34 vs 26.98, p = 0.042) at 1 year postoperatively. Preoperatively, the BMI ≥ 35 cohort had significantly worse frailty (4.5 vs 3.27, p = 0.001), Oswestry Disability Index scores (52.9 vs 44.83, p = 0.017), and T1 pelvic angle (26.82 vs 20.71, p = 0.038). Postoperatively, after controlling for differences in frailty, the BMI ≥ 35 cohort had significantly less improvement in their Scoliosis Research Society-22 outcomes questionnaire scores (0.603 vs 1.05, p = 0.025), higher SVA (64.71 vs 25.33, p = 0.015) and T1 pelvic angle (22.76 vs 15.48, p = 0.029), and less change in maximum Cobb angle (-3.93 vs -10.71, p = 0.034) at 1 year. The BMI 30-34.99 cohort had significantly more infections (11.8% vs 0%, p = 0.004). The BMI ≥ 35 cohort had significantly more implant complications (30% vs 11.8%, p = 0.014) and revision surgery within 90 days (5% vs 1.4%, p = 0.034)., Conclusions: Obese patients who undergo MIS for ASD have less correction of their deformity, worse quality-of-life outcomes, more implant complications and infections, and an increased rate of revision surgery compared with their nonobese counterparts, although both groups benefit from surgery. Appropriate counseling should be provided to obese patients.

Background: There is unclear evidence regarding the optimal surgical approach for multilevel cervical spondylotic myelopathy (CSM). The objective of this study was to compare complications, outcomes, and narcotic use in anterior discectomy and fusion (ACDF) vs posterior decompression and fusion (PCDF) in CSM patients., Study Design: Registry-based retrospective cohort analysis., Methods: Patients undergoing 3-level ACDF or PCDF for CSM between 2007 and 2017 were identified from the Humana Claims Database using relevant procedure codes. Propensity score-matched groups were compared in regards to complications, outcomes, and narcotic use., Results: Propensity score matching generated equal cohorts of 6124 patients. The posterior fusion group had a higher rate of urinary tract infection (OR 2.47, P < 0.0001), deep vein thrombosis (OR 1.90, P < 0.0001), and pulmonary embolism (OR 1.75, P < 0.0001). In regards to 30-day outcomes, the posterior approach demonstrated higher rates of stroke (OR 1.68, P < 0.0001), wound dehiscence (OR 5.59, P < 0.0001), Surgical site infection (SSI) (OR 4.76, P < 0.0001), wound revision surgery (OR 3.02, P < 0.0001), and all-cause readmission (OR 2.01, P < 0.0001). One-year outcomes revealed higher rates of pseudarthrosis (4.7% vs 2.0%, OR 2.43, P < 0.0001) and revision or extension surgery (OR 2.33, P < 0.0001) in the posterior fusion cohort. These patients also demonstrated significantly higher mean morphine milligram equivalent used at 30 days (OR 1.19, P < 0.0001), as well as 60 (OR 1.20, P < 0.0001), 90 (OR 1.21, P < 0.0001), and 120 (OR 1.21, P < 0.0001) days., Conclusions: This nationwide propensity-matched analysis of multilevel CSM patients found the posterior approach to be associated with increased rates of inpatient complications, wound complications, 30-day readmission, 1-year pseudarthrosis, and 1-year revision or extension surgery. These patients also demonstrated higher levels of narcotic use up to 120 days after surgery., Clinical Relevance: The posterior approach for treatment of CSM may be associated with increased rates of short- and long-term complications in addition to increased narcotic consumption in comparison to the anterior approach., Competing Interests: Declaration of Conflicting Interests: Richard G. Fessler reports that he receives consulting fees from Orthofix paid to RGF Spine, LLC. The remaining authors have no disclosures., (This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2022 ISASS. To see more or order reprints or permissions, see http://ijssurgery.com.)

Objective: Previous studies have demonstrated the short-term radiographic and clinical benefits of circumferential minimally invasive surgery (cMIS) and hybrid (i.e., minimally invasive anterior or lateral interbody fusion with an open posterior approach) techniques to correct adult spinal deformity (ASD). However, it is not known if these benefits are maintained over longer periods of time. This study evaluated the 2- and 3-year outcomes of cMIS and hybrid correction of ASD., Methods: A multicenter database was retrospectively reviewed for patients undergoing cMIS or hybrid surgery for ASD. Patients were ≥ 18 years of age and had one of the following: maximum coronal Cobb angle (CC) ≥ 20°, sagittal vertical axis (SVA) > 5 cm, pelvic incidence-lumbar lordosis mismatch (PI-LL) ≥ 10°, or pelvic tilt (PT) > 20°. Radiographic parameters were evaluated at the latest follow-up. Clinical outcomes were compared at 2- and 3-year time points and adjusted for age, preoperative CC, levels operated, levels with interbody fusion, presence of L5-S1 anterior lumbar interbody fusion, and upper and lower instrumented vertebral level., Results: Overall, 197 (108 cMIS, 89 hybrid) patients were included with 187 (99 cMIS, 88 hybrid) and 111 (60 cMIS, 51 hybrid) patients evaluated at 2 and 3 years, respectively. The mean (± SD) follow-up duration for cMIS (39.0 ± 13.3 months, range 22-74 months) and hybrid correction (39.9 ± 16.8 months, range 22-94 months) were similar for both cohorts. Hybrid procedures corrected the CC greater than the cMIS technique (adjusted p = 0.022). There were no significant differences in postoperative SVA, PI-LL, PT, and sacral slope (SS). At 2 years, cMIS had lower Oswestry Disability Index (ODI) scores (adjusted p < 0.001), greater ODI change as a percentage of baseline (adjusted p = 0.006), less visual analog scale (VAS) back pain (adjusted p = 0.006), and greater VAS back pain change as a percentage of baseline (adjusted p = 0.001) compared to hybrid techniques. These differences were no longer significant at 3 years. At 3 years, but not 2 years, VAS leg pain was lower for cMIS compared to hybrid techniques (adjusted p = 0.032). Those undergoing cMIS had fewer overall complications compared to hybrid techniques (adjusted p = 0.006), but a higher odds of pseudarthrosis (adjusted p = 0.039)., Conclusions: In this review of a multicenter database for patients undergoing cMIS and hybrid surgery for ASD, hybrid procedures were associated with a greater CC improvement compared to cMIS techniques. cMIS was associated with superior ODI and back pain at 2 years, but this difference was no longer evident at 3 years. However, cMIS was associated with superior leg pain at 3 years. There were fewer complications following cMIS, with the exception of pseudarthrosis.

Background: Patient satisfaction has become an important variable in assessing outcomes after spine surgery. Although minimally invasive surgery (MIS) techniques have become popular owing to reduced perioperative complications compared with open deformity surgery, whether patient-reported postoperative satisfaction differ between the 2 surgical approaches is unclear. The aim of this study was to characterize postoperative patient-reported outcomes (PRO) in patients who underwent open surgery or MIS for adult spinal deformity (ASD)., Methods: PRO scores were prospectively collected for patients undergoing deformity correction surgery between 2016 and 2018. Inclusion criteria were age >18 years, ASD, and completed PRO surveys. Patient demographic, clinical, and radiographic data and PRO survey responses were analyzed. A post hoc analysis comparing patients who were satisfied with their outcome and those who were unsatisfied was performed., Results: Forty patients who underwent operative management of ASD (19 in the open surgery group and 21 in the MIS group) met the criteria for inclusion in this study. Patients in the MIS group reported higher mental health and self-image scores at 6 months; however, at the 12-month follow-up, both the open surgery and MIS groups reported minimal clinically important differences in back pain, leg pain, and functional status. Patient satisfaction scores did not differ based on surgical approach or intraoperative complications., Conclusions: PRO after open surgery and after MIS for ASD reflected successful outcomes with significant improvements in PRO survey scores but with subtle differences in the postoperative recovery process. The MIS group reported faster recovery with earlier improvement in self-image and mental health scores, which may stem from correction of smaller deformities. At the 12-month follow-up, postoperative satisfaction was high for the majority of patients in both groups., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: Circumferential minimally invasive spine surgery (cMIS) for adult scoliosis has become more advanced and powerful, but direct comparison with traditional open correction using prospectively collected data is limited. The authors performed a retrospective review of prospectively collected, multicenter adult spinal deformity data. The authors directly compared cMIS for adult scoliosis with open correction in propensity-matched cohorts using health-related quality-of-life (HRQOL) measures and surgical parameters., Methods: Data from a prospective, multicenter adult spinal deformity database were retrospectively reviewed. Inclusion criteria were age > 18 years, minimum 1-year follow-up, and one of the following characteristics: pelvic tilt (PT) > 25°, pelvic incidence minus lumbar lordosis (PI-LL) > 10°, Cobb angle > 20°, or sagittal vertical axis (SVA) > 5 cm. Patients were categorized as undergoing cMIS (percutaneous screws with minimally invasive anterior interbody fusion) or open correction (traditional open deformity correction). Propensity matching was used to create two equal groups and to control for age, BMI, preoperative PI-LL, pelvic incidence (PI), T1 pelvic angle (T1PA), SVA, PT, and number of posterior levels fused., Results: A total of 154 patients (77 underwent open procedures and 77 underwent cMIS) were included after matching for age, BMI, PI-LL (mean 15° vs 17°, respectively), PI (54° vs 54°), T1PA (21° vs 22°), and mean number of levels fused (6.3 vs 6). Patients who underwent three-column osteotomy were excluded. Follow-up was 1 year for all patients. Postoperative Oswestry Disability Index (ODI) (p = 0.50), Scoliosis Research Society-total (p = 0.45), and EQ-5D (p = 0.33) scores were not different between cMIS and open patients. Maximum Cobb angles were similar for open and cMIS patients at baseline (25.9° vs 26.3°, p = 0.85) and at 1 year postoperation (15.0° vs 17.5°, p = 0.17). In total, 58.3% of open patients and 64.4% of cMIS patients (p = 0.31) reached the minimal clinically important difference (MCID) in ODI at 1 year. At 1 year, no differences were observed in terms of PI-LL (p = 0.71), SVA (p = 0.46), PT (p = 0.9), or Cobb angle (p = 0.20). Open patients had greater estimated blood loss compared with cMIS patients (1.36 L vs 0.524 L, p < 0.05) and fewer levels of interbody fusion (1.87 vs 3.46, p < 0.05), but shorter operative times (356 minutes vs 452 minutes, p = 0.003). Revision surgery rates between the two cohorts were similar (p = 0.97)., Conclusions: When cMIS was compared with open adult scoliosis correction with propensity matching, HRQOL improvement, spinopelvic parameters, revision surgery rates, and proportions of patients who reached MCID were similar between cohorts. However, well-selected cMIS patients had less blood loss, comparable results, and longer operative times in comparison with open patients.

Lumbar spinal stenosis is a common degenerative condition among the elderly population and a leading cause of morbidity in this age group. A recent Cochrane analysis reviewed the evidence for surgical versus nonsurgical treatment from 5 prospective, randomized controlled studies and concluded that "No clear benefits were observed with surgery versus non-surgical treatment." This is despite the fact that all 5 of the reports analyzed concluded that surgery provided superior outcome compared to nonsurgical therapy. This report analyzes, in detail, the Cochrane analysis of Zaina et al., each of the 5 studies included in the Zaina analysis, and the Cochrane methodology itself. Unlike the ultimate in objectivity sought after by the creators of the Cochrane tool, what is revealed is a remarkably subjective methodology fraught with the potential for bias.

Background: The clinical efficacy of single-level minimally invasive lumbar decompression and/or microdiscectomy is well established, with improved postoperative functional outcome and pain scores. However, there is a paucity of clinical data supporting the use of minimally invasive (MIS) techniques in a single operation to address pathology at multiple lumbar levels, and this study attempts to address this issue., Methods: A retrospective review of prospectively collected data from patients with symptomatic lumbar stenosis and/or disc herniations who underwent multilevel minimally invasive decompression or microdiscectomy from November 2014 to February 2018 was conducted at a single academic medical center. Patient-reported outcome measures (PROMs), including the Oswestry Disability Index (ODI), visual analog scale (VAS) for back and leg pain, 12-Item Short Form Health Survey (SF-12) Physical Component Summary Score (PCS) and Mental Component Summary Score (MCS), and Scoliosis Research Society survey (SRS-30), were prospectively collected before surgery and at 3 months, 6 months, 1 year, and 2 years postoperatively., Results: During the study period, 92 patients received multilevel (≥2 level) MIS lumbar decompression and/or discectomy (69 two level, 21 three level, 2 four level). The mean age at surgery was 69.7 years, and 23 (25%) patients were women. Patient-reported outcomes were significantly improved both in the short and long term except for the SF-12 MCS. Average improvement from baseline was (at 3 months and 2 years, respectively): VAS back, -3.9 and -2.8; VAS leg, -3.6 and -2.6; ODI, -13 and -14.6; SF-12 MCS, 2.8 and -0.3; SF-12 PCS, 6.9 and 10.1; and SRS-30, 0.57 and 0.55. Minimal clinically important difference for the study population was reached for every PROM except SF-12 MCS. Surgical complications occurred in 16 patients (17.4%), and 8 patients (8.6%) required postoperative fusions within 2 years., Conclusion: The use of MIS techniques to perform lumbar decompression and/or discectomy at multiple levels was found to be both clinically effective and durable. Fusion rates remained low 2 years after the index surgery and were consistent with literature data for open procedures., Level of Evidence: 2., (This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2021 ISASS.)

Objective: This study was conducted as a final proof-of-safety direct injection of oligodendrocyte progenitor cells into the uninjured spinal cord prior to translation to the human clinical trials., Methods: In this study, 107 oligodendrocyte progenitor cells (LCTOPC1, also known as AST-OPC1 and GRNOPC1) in 50-μL suspension were injected directly into the uninjured spinal cords of 8 immunosuppressed Göttingen minipigs using a specially designed stereotactic delivery device. Four additional Göttingen minipigs were given Hanks' Balanced Salt Solution and acted as the control group., Results: Cell survival and no evidence of histological damage, abnormal inflammation, microbiological or immunological abnormalities, tumor formation, or unexpected morbidity or mortality were demonstrated., Conclusions: These data strongly support the safety of intraparenchymal injection of LCTOPC1 into the spinal cord using a model anatomically similar to that of the human spinal cord. Furthermore, this research provides guidance for future clinical interventions, including mechanisms for precise positioning and anticipated volumes of biological payloads that can be safely delivered directly into uninjured portions of the spinal cord.

Background: Although advances in implant materials, such as polyetheretherketone (PEEK), have been developed aimed to improve outcome after anterior cervical discectomy and fusion (ACDF), it is essential to confirm whether these changes translate into clinically important sustained benefits., Objective: To compare the radiographic and clinical outcomes of patients undergoing up to 3-level ACDF with PEEK vs structural allograft implants., Methods: In this cohort study, radiographic and symptomatic nonunion rates were compared in consecutive patients who underwent 1 to 3 level ACDF with allograft or PEEK implant. Prospectively collected clinical data and patient-reported outcome (PRO) scores were compared between the allograft and PEEK groups. Regression analysis was performed to determine the predictors of nonunion., Results: In total, 194 of 404 patients met the inclusion criteria (79% allograft vs 21% PEEK). Preoperative demographic variables were comparable between the 2 groups except for age. The rate of radiographic nonunion was higher with PEEK implants (39% vs 27%, P = .0035). However, a higher proportion of nonunion in the allograft cohort required posterior instrumentation (14% vs 3%, P = .039). Patients with multilevel procedures and PEEK implants had up to 5.8 times the risk of radiographic nonunion, whereas younger patients, active smokers, and multilevel procedures were at higher risk of symptomatic nonunion., Conclusion: Along with implant material, factors such as younger age, active smoking status, and the number of operated levels were independent predictors of fusion failure. Given the impact of nonunion on PRO, perioperative optimization of modifiable factors and surgical planning are essential to ensure a successful outcome., (© Congress of Neurological Surgeons 2021.)

Objective: The goal of this study was to evaluate the clinical and radiographic outcomes of a novel multidirectional in situ expandable minimally invasive surgery (MIS) transforaminal lumbar interbody fusion (TLIF) cage., Methods: A retrospective analysis of 69 consecutive patients undergoing a 1- or 2-level MIS TLIF using an expandable cage was performed over a 2-year period. Standard MIS techniques with pedicle screw fixation were used in all cases. Upright lateral dynamic flexion/extension radiographs were reviewed prior to and at 1 year after surgery. Clinical metrics included numeric rating scale for back and leg pain, Oswestry Disability Index, and the SF-12 and VR-12 physical and mental health surveys. Radiographic parameters included anterior and posterior disc height, neuroforaminal height, spondylolisthesis, segmental lordosis, lumbar lordosis, and fusion rate., Results: A total of 69 patients representing 75 operative levels met study inclusion criteria. The mean patient age at surgery was 63.4 ± 1.2 years, with a female predominance of 51%. The average radiographic and clinical follow-ups were 372 and 368 days, respectively. A total of 63 patients (91%) underwent 1-level surgery and 6 patients (9%) underwent 2-level surgery. Significant reductions of numeric rating scale scores for back and leg pain were observed-from 6.1 ± 0.7 to 2.5 ± 0.3 (p < 0.0001) and 4.9 ± 0.6 to 1.9 ± 0.2 (p < 0.0001), respectively. A similar reduction in Oswestry Disability Index from 38.0 ± 4.6 to 20.0 ± 2.3 (p < 0.0001) was noted. Likewise, SF-12 and VR-12 scores all showed statistically significant improvement from baseline (p < 0.001). The mean anterior and posterior disc heights improved from 8.7 ± 1.0 mm to 13.4 ± 1.5 mm (p = 0.0001) and 6.5 ± 0.8 mm to 9.6 ± 1.1 mm (p = 0.0001), respectively. Neuroforaminal height improved from 17.6 ± 2.0 mm to 21.9 ± 2.5 mm (p = 0.0001). When present, spondylolisthesis was, on average, reduced from 4.3 ± 0.5 mm to 1.9 ± 0.2 mm (p = 0.0001). Lumbar lordosis improved from 47.8° ± 5.5° to 58.5° ± 6.8° (p = 0.2687), and no significant change in segmental lordosis was observed. The overall rate of radiographic fusion was 93.3% at 1 year. No perioperative complications requiring operative revision were encountered., Conclusions: In this series of MIS TLIFs, use of this novel interbody cage was shown to be safe and effective. Significant improvements in pain and disability were observed. Effective and durable restoration of disc height and neuroforaminal height and reduction of spondylolisthesis were obtained, with concurrent gains in lumbar lordosis. Taken together, this device offers excellent clinical and radiographic outcomes via an MIS approach.

Objective: The modified frailty index (mFI) is a simple tool that measures physiological reserve based on a thorough history and physical examination. Its use has been validated in several surgical specialties, including spinal deformity surgery. Prior research has suggested no significant differences in clinical outcomes between elderly and nonelderly patients undergoing posterior lumbar interbody fusion. The authors sought to investigate the use of the mFI in patients undergoing transforaminal lumbar interbody fusion (TLIF) and the relationship between frailty scores and clinical outcomes., Methods: A retrospective chart review was conducted on 198 patients who underwent a single-level TLIF over a 60-month period at a single institution. For all patients, an mFI score was computed incorporating a set of 11 clinical factors to assess preexisting comorbidities and functional status. Clinical follow-up and health-related quality-of-life (HRQOL) scores were obtained at baseline and regular intervals of 6 weeks, 6 months, and 1 year following surgery., Results: Patients were grouped according to their level of frailty: no frailty (mFI = 0), mild frailty (mFI = 0.09), moderate frailty (mFI = 0.18), and severe frailty (mFI ≥ 0.27). One-way ANOVA revealed increasing levels of frailty to be associated with an increased rate of complications, from 10.3% to 63.6%. In addition, increasing levels of frailty were associated with longer hospital length of stay (LOS), from 3.1 days to 6.5 days, and lower rates of disposition to home. At the 1-year follow-up, increased levels of frailty were associated with worse HRQOL measures., Conclusions: Increasing mFI score was associated with higher morbidity, longer inpatient LOS, and a lower probability of discharge to home in patients undergoing single-level TLIF. Consideration of the mFI may help surgeons improve decision-making across the spectrum of patients who are at risk from frailty.

Background: Single-level lumbar degenerative disc disease (DDD) remains a significant cause of morbidity in adulthood. Anterior lumbar interbody fusion (ALIF) and Transforaminal lumbar interbody fusion (TLIF) are surgical techniques developed to treat this condition. With limited studies on intermediate term outcomes in a single cohort, we compare radiographic and clinical outcomes in patients undergoing ALIF and TLIF., Methods: A retrospective chart review was performed on 164 patients (111 TLIF; 53 ALIF) over a 60-month period. X-ray radiographs obtained pre-operatively, prior to discharge, and at one year were utilized for radiographic assessment. Segmental lordosis, lumbar lordosis and HRQOL scores were measured preoperatively and at one-year timepoints., Results: Changes in lumbar lordosis and segmental lordosis were significantly greater after ALIF (4.6° vs. -0.6°, P=0.05; 4.7° vs. -0.7°, P<0.05) at one year (mean time, 366±20 days). At one year or greater, there was a greater reduction in mean VAS-leg score in TLIF patients (3.4 vs. 0.6, P<0.05) and ODI score (16.2 vs. 5.4, P<0.05). Similar outcomes were seen for VAS-back, SF-12 Physical Health, and SRS-30 Function/Activity. SF-12 Mental Health scores were found to be lower in patients undergoing TLIF (-3.5 vs. 2.7, P<0.05)., Conclusions: ALIF demonstrated a superior method of increasing lumbar and segmental lordosis. TLIF was utilized more in patients with higher pre-operative VAS-leg pain scores and therefore, showed a greater magnitude of VAS-leg pain improvement. TLIF also demonstrated a greater improvement in ODI scores despite similar baseline scores, suggesting a possible enhanced functional outcome., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/jss-20-673). The authors have no conflicts of interest to declare., (2021 Journal of Spine Surgery. All rights reserved.)

Background: Lateral lumbar interbody fusion (LLIF) affords a wide operative corridor to allow for a large interbody cage implantation for segmental reconstruction. There is a paucity of data describing segmental lordosis (SL) achieved with lordotic implants of varying angles. Here we compare changes in SL and lumbar lordosis (LL) after implantation of 6°, 10°, and 12° cages., Methods: We retrospectively reviewed LLIF cases over a 5.5-year period. We derived SL and LL using the standard cobb angle measurement from a standing lateral radiograph. We analyzed mean changes in SL and LL over time using the linear mixed effect model to estimate these longitudinal changes., Results: The most frequently treated level was L3-4, followed by L4-5. Significant increases in mean SL were found at each follow-up time point for all the cohorts. In an intercohort comparison, the mean changes in SL at immediate postoperative and last follow-up were significantly greater in the 10° cohort than 6° ([7.4° versus 3.1°, P = .004], [6.1° versus 2.3°, P = .025] respectively). The 12° cohort had higher mean change in SL at last follow-up than the 6° cohort (5.9° versus 2.3°, P = .022). There was no difference in mean change in SL between the 10° and 12° cohorts. No difference in overall mean LL over time was found. In terms of mean change in LL, no difference was observed except at immediate and 6-month postoperative in the 10° cohort ([9.6°, P = .001], [8.5, P = .003] respectively). By comparing mean change in LL, no difference existed except between the 10° and 6° immediately after surgery (9.6° versus 0.2°, P = .006)., Conclusions: LLIF cages significantly improve SL at the index level. However, this increase in SL is greater for 10° and 12° cages than the standard 6° cage. Use of 10° cages also resulted in overall improved LL than 6° cages., Level of Evidence: 3., Clinical Relevance: Lateral lumbar interbody fusion., (This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2021 ISASS.)

Background: Spinopelvic parameters have hitherto dictated much of adult spinal deformity (ASD) correction. The Roussouly classification is used for the normal adult spine. We evaluated whether a correlation would be found between the Roussouly type and the rate of revision surgery in patients with ASD undergoing circumferential minimally invasive spinal (cMIS) correction., Methods: A multicenter retrospective review of patients who had undergone cMIS surgery for ASD was performed. The inclusion criteria were age ≥18 years and 1 of the following: coronal Cobb angle >20°, sagittal vertical axis >5 cm, pelvic tilt >20°, pelvic incidence (PI) to lumbar lordosis (LL) mismatch >10°, cMIS surgery, and a minimum of 2 years of follow-up data available. The patients were classified by Roussouly type, and the clinical and radiographic outcomes were evaluated., Results: A total of 104 patients were included in the present analysis. Of the 104 patients, 41 had Roussouly type 1, 32 had type 2, 23 had type 3, and 8 had type 4. Preoperatively, the patients with type 4 had the highest PI (P = 0.002) and LL (P < 0.001). Postoperatively, the PI-LL mismatch, Cobb angle, and sagittal vertical axis were not different among the 4 groups. However, the patients with type 2 had had the highest rate of complications (type 1, 29.3%; type 2, 61.3%; type 3, 34.8%; type 4, 25.0%; P = 0.031). The reoperation rates were comparable (type 1, 19.5%; type 2, 38.7%; type 3, 13.0%; type 4, 12.5%; P = 0.097). The reoperation rates for adjacent segment degeneration or proximal junctional kyphosis were also comparable (P = 0.204 and P = 0.060, respectively)., Conclusions: We did not find a clear correlation between Roussouly type and the rate of revision surgery for adjacent segment disease or proximal junctional kyphosis in patients who had undergone cMIS surgery for ASD., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: Minimally invasive surgery (MIS) for spinal deformity uses interbody techniques for correction, indirect decompression, and arthrodesis. Selection criteria for choosing a particular interbody approach are lacking. The authors created the minimally invasive interbody selection algorithm (MIISA) to provide a framework for rational decision-making in MIS for deformity., Methods: A retrospective data set of circumferential MIS (cMIS) for adult spinal deformity (ASD) collected over a 5-year period was analyzed by level in the lumbar spine to identify surgeon preferences and evaluate segmental lordosis outcomes. These data were used to inform a Delphi session of minimally invasive deformity surgeons from which the algorithm was created. The algorithm leads to 1 of 4 interbody approaches: anterior lumbar interbody fusion (ALIF), anterior column release (ACR), lateral lumbar interbody fusion (LLIF), and transforaminal lumbar interbody fusion (TLIF). Preoperative and 2-year postoperative radiographic parameters and clinical outcomes were compared., Results: Eleven surgeons completed 100 cMISs for ASD with 338 interbody devices, with a minimum 2-year follow-up. The type of interbody approach used at each level from L1 to S1 was recorded. The MIISA was then created with substantial agreement. The surgeons generally preferred LLIF for L1-2 (91.7%), L2-3 (85.2%), and L3-4 (80.7%). ACR was most commonly performed at L3-4 (8.4%) and L2-3 (6.2%). At L4-5, LLIF (69.5%), TLIF (15.9%), and ALIF (9.8%) were most commonly utilized. TLIF and ALIF were the most selected approaches at L5-S1 (61.4% and 38.6%, respectively). Segmental lordosis at each level varied based on the approach, with greater increases reported using ALIF, especially at L4-5 (9.2°) and L5-S1 (5.3°). A substantial increase in lordosis was achieved with ACR at L2-3 (10.9°) and L3-4 (10.4°). Lateral interbody arthrodesis without the use of an ACR did not generally result in significant lordosis restoration. There were statistically significant improvements in lumbar lordosis (LL), pelvic incidence-LL mismatch, coronal Cobb angle, and Oswestry Disability Index at the 2-year follow-up., Conclusions: The use of the MIISA provides consistent guidance for surgeons who plan to perform MIS for deformity. For L1-4, the surgeons preferred lateral approaches to TLIF and reserved ACR for patients who needed the greatest increase in segmental lordosis. For L4-5, the surgeons' order of preference was LLIF, TLIF, and ALIF, but TLIF failed to demonstrate any significant lordosis restoration. At L5-S1, the surgical team typically preferred an ALIF when segmental lordosis was desired and preferred a TLIF if preoperative segmental lordosis was adequate.

Multimodal intraoperative neurophysiologic monitoring (IONM) can be utilized as an adjunct to lumbar spinal instrumentation in order to aid with avoidance of neurologic complications. The most commonly utilized modalities include somatosensory-evoked potentials, motor-evoked potentials, and electromyography. Somatosensory-evoked potentials (SSEPs) allow for continuous assessment of the dorsal columns of the spinal cord and are therefore most useful during procedures with a posterior approach to the cervical and thoracic spine. Motor-evoked potentials (MEPs) and electromyography (EMG) can be applied intermittently to assess motor nerve function. The utility of each individual modality can be largely dependent on the surgical approach. Approaches to lumbar spinal instrumentation can be generally categorized as anterior, lateral, and posterior. For lateral approaches, electromyography can be helpful in identifying neural structures crossing the surgical field to prevent injury. In posterior and anterior approaches, somatosensory-evoked potentials and motor-evoked potentials can be used to assess nerve injury during and after maneuvers for decompression and instrumentation. Additionally, during the placement of pedicle screws, direct stimulation with triggered electromyography can be used to detect the pedicle cortex's breach. The efficacy of intraoperative neuromonitoring is dependent on prompt and accurate recognition of changes in signals. This is then followed by accurate recognition of the cause for these changes and appropriate responses by the surgeon, anesthesiologist, and monitoring personnel to correct the change.

Background: Opioid requirements in the perioperative period in patients undergoing lumbar spine fusion surgery remain problematic. Although minimally invasive surgery (MIS) techniques have been developed, there still remain substantial challenges to reducing length of hospital stay (LOS) because of postoperative opioid requirements., Objective: To study the effect of implementing an enhanced recovery after surgery (ERAS) pathway in patients undergoing a 1-level MIS transforaminal lumbar interbody fusion (MIS TLIF) at our institution., Methods: We implemented an ERAS pathway in patients undergoing an elective single-level MIS TLIF for degenerative changes at a single institution. Consecutive patients were enrolled over a 20-mo period and compared with a pre-ERAS group prior to the implementation of the ERAS protocol. The primary outcome was LOS. Secondary outcomes included reduction in morphine milligram equivalent units (MME), pain scores, postoperative urinary retention (POUR), and incidence of postoperative delirium. Patients were compared using the chi-square and Welch's 2-sample t-tests., Results: A total of 299 patients were evaluated in this study: 87 in the ERAS group and 212 in the pre-ERAS group. In the ERAS group, there was a significant reduction in LOS (3.13 ± 1.53 vs 3.71 ± 2.07 d, P = .019), total admission MME (252.74 ± 317.38 vs 455.91 ± 498.78 MME, P = .001), and the number of patients with POUR (48.3% vs 65.6%, P = .008). There were no differences in pain scores., Conclusion: This is the largest ERAS MIS fusion cohort published to date evaluating a single cohort of patients in a generalizable manner. This ERAS pathway has shown a substantial decrease in LOS and opioid requirements in the immediate perioperative and postoperative period. There is further work to be done to evaluate patients undergoing other complex spine surgical interventions., (© Congress of Neurological Surgeons 2021.)

Background: There is a growing interest in examining preoperative expectations as a potential predictor of postoperative outcome. However, it has never been studied in the setting of adult spinal deformity (ASD). This study aims to characterize patient expectations before ASD surgery and examine the relationship between preoperative expectation and postoperative patient-reported outcomes (PROs)., Methods: Analysis of prospectively collected clinical and PRO data was performed on patients who underwent ASD surgery. Inclusion criteria were age >18 years, a diagnosis of ASD, >3 vertebral level instrumentation, and completed pre- and postoperative surveys. The preoperative expectation survey included expectations of surgical outcome, pain reduction, complications, and the duration of postoperative recovery. Relationships between patient expectations and PROs were assessed., Results: Twenty-seven patients who underwent operative management of ASD met the inclusion criteria. In their preoperative survey, 66% of patients expected highly successful surgery, whereas 22% had a moderate expectation of complications. Patients anticipated an average 71% reduction in back pain (range 42%-100%) and 68% reduction in leg pain (range 0%-100%). Patients who met their expectations of leg pain reduction had significantly greater satisfaction scores than those who did not. There were moderate-to-strong positive correlations between preoperative expectation and observed improvement in back pain, leg pain, and mental health., Conclusions: While substantial variability in patient expectation exists for the surgical management of ASD, patients anticipated a positive outcome with a significant reduction in pain. Greater postoperative satisfaction was associated with patients who met the expected improvement in leg pain. Preoperative expectation was positively correlated with change in pain and mental health scores., (Copyright © 2020 Elsevier Inc. All rights reserved.)