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STUDY DESIGN.: Prospective retrieval analysis of Prodisc-C cervical total disc replacements (CTDRs) from 24 explanting surgeons during a 6-year period. OBJECTIVE.: To determine the in vivo mechanical performance and fixation to bone of explanted Prodisc-C CTDRs. SUMMARY OF BACKGROUND DATA.: The nature and quantity of damage sustained by an implanted device has proven to be important in the prediction of clinical longevity. We hypothesized that retrieval analysis of the Prodisc-C will display characteristic modes of wear consistent with increased posterior angulation and translation of the functional spinal unit after resection of the discoligamentous anatomy. METHODS.: Thirty CTDRs from 29 patients (mean age, 45.1 ± 1.9; range, 31-57 yr) after a mean length of implantation of 1.0 ± 0.2 years (range, 2 d-3.5 yr) were studied. Operative level was C4-C5 in 20% (6 of 30), C5-C6 in 47% (14 of 30), C6-C7 in 20% (6 of 30), and unknown in 13% (4 of 30). Polyethylene and metallic (cobalt chrome molybdenum [CoCrMo]) components were examined using light stereo-microscopy (6X-31X), scanning electron microscopy, and energy dispersive x-ray analysis. RESULTS.: CTDRs were explanted for indications of axial pain (n = 9), radicular symptoms (n = 6), atraumatic loosening (n = 6), trauma (n = 5), metal allergy (n = 1), myelopathy (n = 1), hypermobility (n = 1), and unknown (n = 1). Surface area of ongrowth (mean = 7.2 ± 1.4%) was not associated with operative level (P = 0.37), surgeon-reported axial pain (P = 0.56), or atraumatic loosening (P = 0.93). Burnishing consistent with metallic endplate impingement was present in 80% (24 of 30) of retrieved CTDRs, most commonly in the posterior quadrant (P < 0.001). There was no association between implant height (P = 0.19) or depth (P = 0.17) and posterior impingement. Backside wear was not observed on any of the disassembled implants (0 of 16). Third-body wear occurred in 23% (7 of 30) and the donor site was confirmed by scanning electron microscope/energy dispersive x-ray analysis to be the porous-coated surface of the CTDR. CONCLUSION.: Early clinical failures of Prodisc-C CTDRs display surface damage evidence of metal endplate-endplate impingement, most commonly posteriorly. Backside wear was not evident; however, third-body wear was found. Future studies will determine the clinical impact of these predominant modes of wear on long-term metal-on-polyethylene semiconstrained CTDR performance. [ABSTRACT FROM AUTHOR]

STUDY DESIGN.: A retrieval analysis of wear modes and fixation of lumbar total disc replacements (TDRs). Explanted Prodisc-L TDRs were prospectively collected during a 7-year period (2005-2011) and analyzed. OBJECTIVE.: To assess the in vivo modes of wear and fixation of lumbar TDR with the Prodisc-L device. SUMMARY OF BACKGROUND DATA.: Inferior clinical outcomes and failure of lumbar TDR may occur because of suboptimal component fixation, wear properties, and impingement in a subset of patients. Posterior component TDR impingement has been demonstrated radiographically; however, despite its widespread use, the in vivo mechanical performance and fixation of the Prodisc-L device remain unknown. METHODS.: Explanted polyethylene and metallic (CoCrMo) components of Prodisc-L devices were examined by light stereo-microscopy (6X-31X), scanning electron microscopy, and energy-dispersive x-ray analysis from an international retrieval registry, with 13 participating surgeons. RESULTS.: Nineteen ProDisc-L devices from 18 patients (age, 44.7 ± 2.9 yr) following an index TDR at L4-L5 (n = 6), L5-S1 (n = 11), and unknown level (n = 2) were explanted for pain (n = 8), prosthesis subluxation/migration (n = 4), end plate collapse/subsidence (n = 3), polyethylene dislodgement (n = 3), and unknown (n = 2) after a mean length of implantation of 13.0 ± 3.9 months. Surface area of bony ongrowth was 9.6 ± 2.9% (range, 0%-52.5%). TDR burnishing was observed posteriorly consistent with component impingement in extension in 53% (8/15) (P < 0.02), more commonly than anterior 20% (3/15) lateral 20% (n = 3) (3/15) patterns. Circumferential burnishing was not observed. Posterior impingement was associated with 6° lordotic implants (P < 0.05) and 10-mm polyethylene size (P < 0.05). Backside wear occurred in 75% (9 of 12) of the disassembled implants and third-body wear was observed in 33% (5 of 15). CONCLUSION.: Metallic end plate burnishing was evident in a large percentage of clinically failed Prodisc-L TDR devices, most commonly posteriorly, consistent with impingement in extension. Long-term follow-up studies will evaluate the effects of the observed backside wear, third-body wear, and end plate impingement on clinical outcomes. [ABSTRACT FROM AUTHOR]

Background: Robotic-assisted spine surgery has been reported to improve the accuracy and safety of pedicle screw placement and to reduce blood loss, hospital length of stay, and early postoperative pain 1 . Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) is a procedure that is well suited to be improved by recent innovations in robotic-assisted spine surgery. Heretofore, the capability of robotic navigation and software in spine surgery has been limited to assistance with pedicle screw insertion. Surgical decompression and decortication of osseous anatomy in preparation for biological fusion had historically been outside the scope of robotic-assisted spine surgery. In 2009, early attempts to perform surgical decompressions in a porcine model utilizing the da Vinci Surgical Robot for laminotomy and laminectomy were limited by the available technology 2 . Recent advances in software and instrumentation allow registration, surgical planning, and robotic-assisted surgery on the posterior elements of the spine. A human cadaveric study assessed the accuracy of robotic-assisted bone laminectomy, revealing precision in the cutting plane 3 . Robotic-assisted facet decortication, decompression, interbody cage implantation, and pedicle screw fixation add automation and accuracy to MI-TLIF., Description: A surgical robotic system comprises an operating room table-mounted surgical arm with 6 degrees of freedom that is physically connected to the patient's osseous anatomy with either a percutaneous Steinmann pin to the pelvis or a spinous process clamp. The Mazor X Stealth Edition Spine Robotic System (Version 5.1; Medtronic) is utilized, and a preoperative plan is created with use of software for screw placement, facet decortication, and decompression. The workstation is equipped with interface software designed to streamline the surgical process according to preoperative planning, intraoperative image acquisition, registration, and real-time control over robotic motion. The combination of these parameters enables the precise execution of preplanned facet joint decortication, osseous decompression, and screw trajectories. Consequently, this technique grants the surgeon guidance for the drilling and insertion of screws, as well as guidance for robotic resection of bone with a bone-removal drill., Alternatives: The exploration of robotically guided facet joint decortication and decompression in MI-TLIF presents an innovative alternative to the existing surgical approaches, which involve manual bone removal and can be less precise. Other robotic systems commonly utilized in spine surgery include the ROSA (Zimmer Biomet), the ExcelsiusGPS (Globus Medical), and the Cirq (Brainlab) 4 ., Rationale: The present video article provides a comprehensive guide for executing robotic-assisted MI-TLIF, including robotic facet decortication and osseous decompression. The introduction of advanced robotic technology capable of both decompressing bone and providing implant guidance represents a considerable advancement in robotic-assisted spine surgery. Software planning for robotic-assisted decortication of fused surfaces, surgical decompression, interbody cage placement, and pedicle screw placement allows for a less invasive and more precise MI-TLIF., Expected Outcomes: Anticipated outcomes include reduction in low back and leg pain, improved functional status, and successful spinal fusion. Radiographic outcomes are expected to show restored foraminal height and solid bony fusion. Further, enhanced surgical precision, reduced approach-related morbidity by expanded robotic capabilities in spinal fusion surgery, and a shift from manual bone removal to precise mechanized techniques can be expected. The introduction of robotic-assisted facet joint decortication and decompression represents a notable milestone in spine surgery, enhancing patient care and technological advancement., Important Tips: Although robotic systems were initially predominantly employed for thoracic or lumbar pedicle screw insertion, recent advancements in robotic technology and software have allowed registration of the posterior elements. This advancement has expanded the utility of robotic systems to the initiation of spinal decompression and the decortication of facet joint surfaces, enhancing fusion procedures.Maintaining anatomical precision and preventing the need for re-registration are critical considerations in this surgical procedure. It is recommended to follow a consistent surgical workflow: facet decortication, decompression, modular screw placement, discectomy, insertion of an interbody cage, placement of reduction tabs, rod insertion, and set screw locking.The incorporation of robotic assistance in MI-TLIF is not exempt from a set of challenges. These encompass issues that pertain to dependability of the setup process, occurrences of registration failures, logistical complexities, time constraints, and the unique learning curve associated with the novel capability of robotic decompression of bone and facet joints., Acronyms and Abbreviations: MI-TLIF= minimally invasive transforaminal lumbar interbody fusionOR = operating roomPSIS= posterior superior iliac spineCT = computed tomographyAP = anteroposterior., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSEST/A476)., (Copyright © 2024 by The Journal of Bone and Joint Surgery, Incorporated.)

For years, anterior cervical diskectomy and fusion has been considered the benchmark for patients with cervical radiculopathy/myelopathy. However, concerns regarding adjacent segment pathology have promoted the popularity of cervical disk arthroplasty (CDA) with its motion-preserving properties. To replicate the natural cervical disk's six degrees of freedom and compressibility in cervical spine implants, designers need to carefully consider the level of constraint for stability and material selection. Recent CDA designs have incorporated strategies to facilitate unrestricted or semirestricted motion, deploying various articulating components and materials with distinct wear and compressibility properties. To optimize outcomes, patient selection considering additional degeneration of the cervical spine is critical. Clinical long-term studies have been reported in industry-funded FDA investigational device exemption and nonindustry-funded data for one-level and two-level CDA. There are limited data available on three-level and four-level CDA. Adverse events such as heterotopic ossification, osteolysis, migration, subsidence, and failure have been described, where analysis from explanted devices yields insight into in vivo wear and impingement performance. CDA has shown short-term cost advantages, such as decreased procedural expenses. Nonetheless, long-term analysis is necessary to assess possible economic tradeoffs. Advancements in designs may lead to improved implant longevity while evidence-based decision making will guide and responsibly manage the rapid advancement in CDA technology., (Copyright © 2024 by the American Academy of Orthopaedic Surgeons.)

Study Design: Review of cohort studies., Objective: To ascertain if previous hip (THA) or knee (TKA) arthroplasty was associated with patients' outcomes assessments of subsequent lumbar surgery, specifically overall satisfaction, less disability due to pain, and an affective appraisal reflecting emotional assessment of results., Background: Hip, knee, and lumbar symptoms often co-exist and increasingly are managed with surgery. Whether previous total joint arthroplasty (TJA) impacts patients' perspectives of results of subsequent lumbar surgery is not known., Methods: Identical and systematically acquired preoperative and postoperative data from 3 studies assessing psychosocial characteristics and outcomes of lumbar surgery were pooled. Data obtained during interviews included preoperative demographic and clinical variables and 2-year postoperative global overall assessment (very satisfied/satisfied, neither, dissatisfied/very dissatisfied) and global affective assessment (delighted/pleased, mostly satisfied/mixed/mostly dissatisfied, unhappy/terrible). Patients completed the ODI and preoperative to postoperative change was analyzed according to an MCID (15 points). At 2 years patients also reported any untoward events since surgery (ie, fracture, infection, or repeat lumbar surgery). Associations with outcomes were assessed with multivariable logistic ordinal regression controlling for untoward events. Type of arthroplasty was evaluated in subanalyses., Results: Among 1227 patients (mean: 59 y, 50% women), 12% had arthroplasty (+TJA) and 88% did not (-TJA). In multivariable analysis, +TJA was associated with less global satisfaction (OR: 1.9, CI: 1.3-2.7, P=0.0007), worse global affective assessment (OR: 1.6, CI: 1.1-2.2, P=0.009), and not meeting MCID15 (OR: 1.5, CI: 1.0-2.3, P=0.05). Covariables associated with less favorable outcomes were not working, positive depression screen, and prior lumbar surgery. Compared with -TJA, patients with THA had worse affective assessments and patients with TKA had less satisfaction and were less likely to meet MCID15., Conclusions: Previous hip or knee arthroplasty was associated with less favorable patient-reported outcomes of lumbar surgery. Surgeons and patients should discuss differences between procedures preoperatively and during shared postoperative outcome assessment., Level of Evidence: Level II., Competing Interests: The authors declare no conflict of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background Context: Preoperative imaging for lumbar spine surgery often includes magnetic resonance imaging (MRI) for soft tissues and computer tomography (CT) for bony detail. While CT scans expose patients to ionizing radiation, whereas MRI scans do not. Emerging MRI techniques allow CT-like 3-dimensional (3D) visualization of bony structures, potentially removing the need for ionizing radiation from CT scans., Purpose: This study aims to explore the accuracy of robot-assisted lumbar pedicle screw placement based on preoperative CT-like 3D MRI as the data source for robotic registration., Study Design: Human cadaveric study., Methods: CT-like 3D MRI scans of the lumbar spine were acquired in ten human cadavers. A robotic navigation platform was used to plan and navigate pedicle screw placement based on the CT-like 3D MRI. Postoperative CT scans assessed the accuracy of screw positioning compared to preoperative planning based on the Gertzbein-Robbins scale (GRS) and by direct measurement (mm)., Results: A total of 100 lumbar pedicle screws were robotically placed in ten cadavers (L1 through L5 bilaterally) based on CT-like 3D MRI. On postoperative CT evaluation, 99.0% of the positioned screws achieved an acceptable grade on the GRS (Grade A: n=89 or Grade B: n=10), with 89.0% classified as Grade A and 10.0% as Grade B. Meaning that 89.0% of screws were fully contained within the pedicle (GRS A), and 10% had a minor cortical breach <2 mm (GRS B). The median deviation from the planned trajectory was 0.2 mm (axial IQR: 0.1 to 0.5 mm; sagittal: IQR: 0.1 to 0.4 mm), in both axial and sagittal planes., Conclusion: This study showed that image registration of CT-like 3D MRI for robotic-assisted spine surgery is technically feasible and that accurate pedicle screw placement can be achieved without preoperative CT. Each CT-like 3D MRI was successfully registered for robotic navigation., Clinical Significance: The results suggest that CT-like 3D MRI has the potential to be a radiation-free alternative for preoperative planning and navigation in lumbar spine instrumentation procedures., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

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

Competing Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: DBS reports relationships with AMAG Pharmaceuticals, Inc., General Electric Healthcare, Private Health Management, RemedyLogic, Siemens Healthcare, USA. DRL reports relationships with Choice Spine, Depuy Synthes, HS2, LLC, ISPH II, LLC, Medtronic Sofamor Danek USA, Inc., Nuvasive, Inc., Remedy Logic, Stryker, Vestia Ventures, MiRus Investment LLC, Viseon, Inc., Woven Orthopedic Technologies. The other authors declared no potential conflicts of interest.

Study Design: Retrospective database review., Objective: The aim of this study was to analyze revisions of CDAs reported to the MAUDE database., Summary of Background Data: Cervical disk arthroplasty (CDA) has emerged as a motion-preserving alternative to anterior cervical discectomy and fusion (ACDF) for degenerative cervical disease, demonstrating comparable outcomes. Despite the availability of variable CDA designs, there is limited data on the specific complications of individual CDAs. The Drug Administration's Manufacturer and User Facility Device Experience (MAUDE) database has been used to systematically report complications associated with CDAs. However, data on specific reasons for CDA revision remains scarce. The purpose of this study is to compare common complications associated with revision for different CDAs., Methods: The MAUDE database was queried from January 2005 to September 2023, including all nine FDA-approved CDAs. The full-text reports of each complication were categorized based on whether revision surgery was performed, the complications and the type of CDA collected and compared., Results: A total of 678 revisions for nine CDAs were reported: Mobi-C (239), M6 (167), Prodisc-C (88), Prestige (60), PCM (44), Bryan (35), Secure (23), Simplify (21), and Discover (1). The top three complications associated with revision were migration (23.5%), neck pain (15.5%), and heterotopic ossification (6.6%). The most common complications per device were migration for Mobi-C (26.4%), Prodisc-C (21.3%), Prestige (24.6%), PCM (84.1%), Bryan (48.6%), Secure (30.4%), and Discover (100%). For M6, the most common complications associated with revision surgery were osteolysis (18.6%) and neck pain (18.6%), while neck pain (23.8%) was the most common for the Simplify., Conclusions: The MAUDE database highlights complications related to CDA revision in which the primary complications consistently include implant migration, neck pain, and heterotopic ossification, varying in their rerelvance depending on the CDA., Level of Evidence: Level II., Competing Interests: C.A. is a consultant on the advisory board for Camber Spine Tech; a consultant for Centinel Spine Inc.; is in the advisory board, and has an ownership interest in Orthobond Corporation and Surgalign. D.R.L. is a consultant and on the advisory board for Choice Spine; is a consultant for Depuy Synthes; has ownership interest from Woven Orthopedic Technologies, Vestia Ventures MiRus Investment LLC, HS2 LLC, and ISPH II LLC; has research support from Medtronic Sofamor Danek USA Inc.; has royalties from Nuvasive Inc.; is on the advisory board and has ownership interest from Remedy Logic; is a consultant and has royalties from Stryker; is a consultant and has ownership interest from Viseon Inc. The remaining authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Introduction: Hip, knee, and lumbar spine surgeries are prevalent with arthroplasty often preceding lumbar surgery. The objective of this analysis was to ascertain whether previous arthroplasty was associated with patients' postlumbar surgery fulfillment of expectations., Methods: Identical systematically acquired data were pooled from 3 prospective studies that included assessments of preoperative expectations of lumbar surgery and 2-year postoperative assessment of fulfillment of expectations using a valid survey with points assigned for amount of improvement expected for symptoms and function. The proportion of expectations fulfilled was defined as total points for improvement received postoperatively divided by total points for improvement expected preoperatively (range 0 [no expectations fulfilled] to >1 [expectations surpassed]). Enrollment data included the expectations survey, demographic/clinical characteristics, Oswestry Disability Index (ODI) scores, and previous hip/knee arthroplasty. Postoperative data included follow-up expectations survey, ODI scores, and any spine complications. The proportion was the dependent variable in multivariable linear regression with demographic/clinical independent variables., Results: 1137 patients were included (mean age 59 years, 51% male); 993 (87%) did not have previous arthroplasty, and 144 (13%) had arthroplasty (51 hip only, 77 knee only, 16 both hip/knee). Patients with any arthroplasty had similarly high expectations compared with patients with no arthroplasty but lower proportion of expectations fulfilled (0.69 versus 0.76, P = 0.03). In multivariable analysis, variables associated with a lower proportion of expectations fulfilled were greater preoperative expectations ( P < 0.0001), not working ( P < 0.0001), positive depression screen ( P = 0.0002), previous lumbar surgery ( P < 0.0001), previous arthroplasty ( P = 0.03), surgery on ≥3 vertebrae ( P = 0.007), less preoperative-to-postoperative ODI improvement ( P < 0.0001), and postoperative complications ( P < 0.0001)., Conclusions: After accounting for a spectrum of highly associated covariates, patients with previous arthroplasty still had less fulfillment of expectations of subsequent lumbar surgery. For patients with previous arthroplasty, surgeons should discuss potential differences between arthroplasty and lumbar surgery during preoperative evaluations and during shared postoperative assessments of the outcome., (Copyright © 2024 by the American Academy of Orthopaedic Surgeons.)

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

Aims: To report the development of the technique for minimally invasive lumbar decompression using robotic-assisted navigation., Methods: Robotic planning software was used to map out bone removal for a laminar decompression after registration of CT scan images of one cadaveric specimen. A specialized acorn-shaped bone removal robotic drill was used to complete a robotic lumbar laminectomy. Post-procedure advanced imaging was obtained to compare actual bony decompression to the surgical plan. After confirming accuracy of the technique, a minimally invasive robotic-assisted laminectomy was performed on one 72-year-old female patient with lumbar spinal stenosis. Postoperative advanced imaging was obtained to confirm the decompression., Results: A workflow for robotic-assisted lumbar laminectomy was successfully developed in a human cadaveric specimen, as excellent decompression was confirmed by postoperative CT imaging. Subsequently, the workflow was applied clinically in a patient with severe spinal stenosis. Excellent decompression was achieved intraoperatively and preservation of the dorsal midline structures was confirmed on postoperative MRI. The patient experienced improvement in symptoms postoperatively and was discharged within 24 hours., Conclusion: Minimally invasive robotic-assisted lumbar decompression utilizing a specialized robotic bone removal instrument was shown to be accurate and effective both in vitro and in vivo. The robotic bone removal technique has the potential for less invasive removal of laminar bone for spinal decompression, all the while preserving the spinous process and the posterior ligamentous complex. Spinal robotic surgery has previously been limited to the insertion of screws and, more recently, cages; however, recent innovations have expanded robotic capabilities to decompression of neurological structures., Competing Interests: D. R. Lebl discloses being a consultant and on the advisory board for Choice Spine; being a consultant for Depuy Synthes; having an ownership interest in HS2, ISPH, and Vestia Ventures MiRus Investment; being a consultant and having ownership interest in Viseon; being a consultant and having royalties from Stryker; receiving royalties from Nuvasive; and getting research support form Medtronic Sofamor Danek USA, all of which is unrelated to this manuscript. D. B. Sneag declares research support from GE Healthcare, Siemens Healthcare, Medtronic, and AMAG Pharmaceuticals, which are unrelated to this work. J. L. Chazen reports being a consultant for Lexeo Therapeutics, which is also unrelated., (© 2024 Lebl et al.)

Instrumentation of the upper cervical spine, such as cervical pedicle, lateral mass, pars, or translaminar screws, is considered high risk due to the specific challenges of this anatomic region, including the proximity of vertebral and carotid arteries and nerve roots, as well as its delicate bony architecture. In recent years, advanced three-dimensional (3D) imaging techniques, such as intraoperative computed tomography (iCT; AIRO CT), have emerged, enabling computer-assisted navigation (CAN). This integration of real-time imaging into navigation enhances screw accuracy and diminishes perioperative risks, extending to the postsurgical confirmation of screw placement. Although CAN utilization has become more prominent in lumbar and thoracic surgeries, its integration into cervical spine procedures has been constrained thus far. This can be ascribed to the variable screw trajectories necessary for cervical spine procedures, coupled with potential anatomical variations such as a high-riding vertebral artery, increasing the degree of challenge during surgery. To date, no study has comprehensively described in detail the technique of upper cervical instrumentation employing automatic image registration, navigation, and iCT validation of the positioned screws. In this manuscript, a detailed description of CAN in high cervical instrumentation is given, including C1 lateral mass screws with the notching technique, C2 and C3 pars screws, and translaminar screws guided by preoperative magnetic resonance imaging (MRI) data and iCT for assessment of screw position. For this purpose, three different patients suffering from distinct cervical pathologies, such as nonunion of a C2 fracture and atlantoaxial arthropathy with or without ankylosis, are presented, with a specific surgical approach tailored to the anatomical variations of each patient., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-24-26/coif). D.R.L. reports research support from Medtronic; royalties from NuVasive, Inc. and Stryker; consulting fee from Depuy Synthes and Vizeon, Inc.; private investments from HS2, LLC, Woven Orthopedic Technologies, Vestia Ventures MiRus Investiment LLC, ISPH, and LLC; and he is the member of scientific advisory board of Remedy Logic. The other authors have no conflicts of interest to declare., (2024 AME Publishing Company. All rights reserved.)

Study Design: This was a single-center prospective clinical and radiographic analysis of pedicle screw instrumentation with Robotic-assisted navigation (RAN) and augmented reality (AR)., Objective: This study aimed to compare the accuracy of lumbosacral pedicle screw placement with RAN versus AR., Summary of Background Data: RAN and AR have demonstrated superior accuracy in lumbar pedicle screw placement compared to conventional free-hand techniques. RAN and AR techniques both tout specific advantages over their counterparts, but to date, no study has directly compared the two technologies regarding pedicle screw accuracy., Patients and Methods: Patients who underwent RAN or head-mounted AR navigated lumbosacral (L1-S1) pedicle screw placement for degenerative conditions were included. Screw accuracy was assessed by two independent reviewers on intraoperative 3D fluoroscopic scans using the Gertzbein and Robbins scale. A generalized linear mixed model was applied to evaluate the relationship between the screw placement technique and accuracy., Results: 212 patients undergoing lumbosacral instrumentation with a total of 1,211 pedicle screws placed using RAN (n=108; screws= 827) or AR (n=104; screws= 384). Overall, Grade A was achieved in 92.6% of screws. No significant difference was found between RAN and AR screw placement regarding the incidence of accurate (Grade-A and -B screws; RAN n=824; 99.6% and AR n=379, 98.7%) versus inaccurate screws (Grade-C and -D screws; RAN n=3, 0.4% and AR n=5, 1.3%). When comparing "optimal" Grade-A screws (RAN n= 787, 95.2%, AR n=345, 89.8%) versus all other screws (B, C, and D), significantly higher accuracy was achieved using RAN (P=0.001)., Conclusion: RAN and AR both achieved high accuracy in lumbosacral pedicle screw placement, proving reliable for this procedure. However, RAN resulted in significantly more Grade-A screw placements than AR., Competing Interests: Conflict of interest disclosure: FCSA, MJK, FA, MDB, JZ, and FA do not have a conflict of interest in this study. FPC received research support and/or has an ownership interest in 4WEB Medical/4WEB, Inc., Camber Spine, Centinel Spine, Choice Spine, DePuy Synthes, and Royal Biologics. Has ownership interests in 4WEB Medical/4WEB, Inc., Healthpoint Capital Partners, LP, ISPH II, LLC, where FPC is also in the advisory board, ISPH 3 Holdings, LLC, Ivy Healthcare Capital Partners, LLC, Medical Device Partners II, LLC, Medical Device Partners III, LLC, where FPC is also in the Board of directors, Orthobond Corporation, where FPC is on the board of directors, Spine Biopharma, LLC, Tissue Differentiation Intelligence, LLC, Tissue Connect Systems, Inc., VBVP VI, LLC, VBVP X, LLC, and Woven Orthopedic Technologies, where FPC is also in the Board of directors. FPC has consulting and royalty agreements with Accelus and Spine Biopharma, LLC, with royalties specifically for the “Toro” titanium, bi-planar expandable, lumbar spine interbody implant designed for insertion via lateral approach from Accelus. FCP is in the board of Director positions with Medical Device Partners II, LLC, Orthobond Corporation, Spine Biopharma, LLC, with ownership interest, and Woven Orthopedic Technologies. FCP is on the Advisory Board and has ownership interest with Healthpoint Capital Partners, LP. AS has Ownership Interest from Centinel Spine (Vbros Venture Partners V), HSS ASC Development Network, LLC, HS2, LLC, ISPH 3 Holdings, LLC, ISPH II, LLC, VBros Venture Partners X, and Vestia Ventures MiRus Investment, LLC. AS is a Consultant and on the Scientific Advisory Board for Clariance, Inc. AS is on the Advisory Board and a Consultant for Depuy Synthes Products, Inc. (a Johnson & Johnson Company). AS is a Consultant and on the Strategic Advisory Board for Kuros Biosciences. AS is a Consultant and has Royalties from Ortho Development Corp. MF is Consultant for Arthrex and Medacta, and President of the Board and shareholder of Moving Spine DRL is a Consultant and on the Advisory Board for Choice Spine. DRL is a consultant for Depuy Synthes. DRL has Ownership Interest from Woven Orthopedic Technologies, Vestia Ventures MiRus Investment LLC HS2, LLC and ISPH II, LLC. DRL has Research Support from Medtronic Sofamor Danek USA, Inc. DRL has Royalties from Nuvasive, Inc. DRL is on the Advisory Board and has Ownership Interest from Remedy Logic. DRL is a Consultant and has Royalties from Stryker. DRL is a Consultant and has Ownership Interest from Viseon, Inc., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: Surgeons' preoperative expectations of lumbar surgery may be associated with patient-reported postoperative outcomes., Methods: Preoperatively spine surgeons completed a validated Expectations Survey for each patient estimating amount of improvement expected (range 0-100). Preoperative variables were clinical characteristics, spine-specific disability (ODI), and general health (RAND-12). Two years postoperatively patients again completed these measures and global assessments of satisfaction. Surgeons' expectations were compared to preoperative variables and to clinically important pre- to postoperative changes (MCID) in ODI, RAND-12, and pain and to satisfaction using hierarchical models., Results: Mean expectations survey score for 402 patients was a 57 (IQR 44-68) reflecting moderate expectations. Lower scores were associated with preoperative older age, abnormal gait, sensation loss, vacuum phenomena, foraminal stenosis, prior surgery, and current surgery to more vertebrae (all p ≤ .05). Lower scores were associated postoperatively with not attaining MCID for the ODI (p = .02), RAND-12 (p = .01), and leg pain (p = .01). There were no associations between surgeons' scores and satisfaction (p = .06-.27). 55 patients (14%) reported unfavorable global outcomes and were more likely to have had fracture/infection/repeat surgery (OR 3.2, CI 1.6-6.7, p = .002)., Conclusion: Surgeons' preoperative expectations were associated with patient-reported postoperative improvement in symptoms and function, but not with satisfaction. These findings are consistent with clinical practice in that surgeons expect some but not complete improvement from surgery and do not anticipate that any particular patient will have markedly unfavorable satisfaction ratings. In addition to preoperative discussions about expectations, patients and surgeons should acknowledge different types of outcomes and address them jointly in postoperative discussions., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Anterior cervical discectomy and fusion (ACDF) is known to elicit adverse biomechanical effects on immediately adjacent segments; however, its impact on the kinematics of the remaining nonadjacent cervical levels has not been understood. This study aimed to explore the biomechanical impact of ACDF on kinematics beyond the immediate fusion site. We hypothesized that compensatory motion following single-level ACDF is not predictably distributed to adjacent segments due to compensation from noncontiguous levels., Methods: Six fresh-frozen cervical spines (C2-T1) underwent fluoroscopic screening and sagittal and coronal reformats from computed tomography scans and were utilized to grade segmental degeneration. Each specimen was tested to 30° of flexion and extension intact and following single-level ACDF at the C5-C6 level. The motions of each vertebral body were tracked using 3-dimensional (3D) motion capture into an inverse kinematics model, facilitating correlations between the 3D reconstruction from computed tomography images and the 3D motion capture data. This model was used to calculate each level's flexion/extension range of motion (ROM)., Results: Single-level fusion at the C5-C6 level across all specimens resulted in a significant motion reduction of -6.8° ( P = 0.002). No significant change in ROM occurred in the immediate adjacent segments C4-C5 ( P = 0.07) or C6-C7 ( P = 0.15). Hypermobility was observed in 2 specimens (33%) exclusively in adjacent segments. In contrast, the other 4 spines (66%) displayed hypermobility at noncontiguous segments. Hypermobility occurred in 42% (5/12) of the adjacent segments, 28% (5/18) of the noncontiguous segments, and 50% (3/6) of the cervicothoracic segments., Conclusion: Single-level ACDF impacts ROM beyond adjacent segments, extending to noncontiguous levels. Compensatory motion, not limited to adjacent levels, may be influenced by degenerative changes in noncontiguous segments. Surprisingly, hypermobility may not occur in adjacent segments after ACDF., Clinical Relevance: Overall, the multifaceted biomechanical effects of ACDF underscore the need for a comprehensive understanding of cervical spine dynamics beyond immediate adjacency, and it needs to be taken into consideration when planning single-level ACDF., Competing Interests: Declaration of Conflicting Interests : The authors report no conflicts of interest in this work., (This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2024 ISASS. To see more or order reprints or permissions, see http://ijssurgery.com.)

Study Design: Medical vignettes., Objectives: Lumbar spinal stenosis (LSS) is a degenerative condition with a high prevalence in the elderly population, that is associated with a significant economic burden and often requires spinal surgery. Prior authorization of surgical candidates is required before patients can be covered by a health plan and must be approved by medical directors (MDs), which is often subjective and clinician specific. In this study, we hypothesized that the prediction accuracy of machine learning (ML) methods regarding surgical candidates is comparable to that of a panel of MDs., Methods: Based on patient demographic factors, previous therapeutic history, symptoms and physical examinations and imaging findings, we propose an ML which computes the probability of spinal surgical recommendations for LSS. The model implements a random forest model trained from medical vignette data reviewed by MDs. Sets of 400 and 100 medical vignettes reviewed by MDs were used for training and testing., Results: The predictive accuracy of the machine learning model was with a root mean square error (RMSE) between model predictions and ground truth of .1123, while the average RMSE between individual MD's recommendations and ground truth was .2661. For binary classification, the AUROC and Cohen's kappa were .959 and .801, while the corresponding average metrics based on individual MD's recommendations were .844 and .564, respectively., Conclusions: Our results suggest that ML can be used to automate prior authorization approval of surgery for LSS with performance comparable to a panel of MDs., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. FundingAB and RM were supported by Université Paul Sabatier and Remedy Logic. SK was supported by Vinnitsa National Medical University and Remedy Logic. OS, JK, and AR were supported by Remedy Logic.

Background Only a few studies have examined the impact of the coronavirus disease 2019 pandemic on spine ambulatory surgeries and changes in trends. Therefore, we investigated trends during the pre-pandemic period and three pandemic stages in patients undergoing lumbar decompression procedures in the ambulatory surgery (AMS) setting. Methodology A total of 2,670 adult patients undergoing one- or two-level lumbar decompression surgery were retrospectively reviewed. Patients were categorized into the following four groups: 1: pre-pandemic (before the pandemic from January 1, 2019, to March 16, 2020); 2: restricted period (when elective surgery was canceled from March 17, 2020, to June 30, 2020); 3: post-restricted 2020 (July 1, 2020, to December 31, 2020, before vaccination); and 4: post-restricted 2021 (January 1, 2021 to December 31, 2021 after vaccination). Simple and multivariable logistic regression analyses as well as retrospective interrupted time series (ITS) analysis were conducted comparing AMS patients in the four periods. Results Patients from the restricted pandemic period were younger and healthier, which led to a shorter length of stay (LOS). The ITS analysis demonstrated a significant drop in mean LOS at the beginning of the restricted period and recovered to the pre-pandemic levels in one year. Multivariable logistic regression analyses indicated that the pandemic was an independent factor influencing the LOS in post-restricted phases. Conclusions As the post-restricted 2020 period itself might be independently influenced by the pandemic, these results should be taken into account when interpreting the LOS of the patients undergoing ambulatory spine surgery in post-restricted phases., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Dodo et al.)

Background Context: Machine learning is a powerful tool that has become increasingly important in the orthopedic field. Recently, several studies have reported that predictive models could provide new insights into patient risk factors and outcomes. Anterior cervical discectomy and fusion (ACDF) is a common operation that is performed as an outpatient procedure. However, some patients are required to convert to inpatient status and prolonged hospitalization due to their condition. Appropriate patient selection and identification of risk factors for conversion could provide benefits to patients and the use of medical resources., Purpose: This study aimed to develop a machine-learning algorithm to identify risk factors associated with unplanned conversion from outpatient to inpatient status for ACDF patients., Study Design/setting: This is a machine-learning-based analysis using retrospectively collected data., Patient Sample: Patients who underwent one- or two-level ACDF in an ambulatory setting at a single specialized orthopedic hospital between February 2016 to December 2021., Outcome Measures: Length of stay, conversion rates from ambulatory setting to inpatient., Methods: Patients were divided into two groups based on length of stay: (1) Ambulatory (discharge within 24 hours) or Extended Stay (greater than 24 hours but fewer than 48 hours), and (2) Inpatient (greater than 48 hours). Factors included in the model were based on literature review and clinical expertise. Patient demographics, comorbidities, and intraoperative factors, such as surgery duration and time, were included. We compared the performance of different machine learning algorithms: Logistic Regression, Random Forest (RF), Support Vector Machine (SVM), and Extreme Gradient Boosting (XGBoost). We split the patient data into a training and validation dataset using a 70/30 split. The different models were trained in the training dataset using cross-validation. The performance was then tested in the unseen validation set. This step is important to detect overfitting. The performance was evaluated using the area under the curve (AUC) of the receiver operating characteristics analysis (ROC) as the primary outcome. An AUC of 0.7 was considered fair, 0.8 good, and 0.9 excellent, according to established cut-offs., Results: A total of 581 patients (59% female) were available for analysis. Of those, 140 (24.1%) were converted to inpatient status. The median age was 51 (IQR 44-59), and the median BMI was 28 kg/m 2 (IQR 24-32). The XGBoost model showed the best performance with an AUC of 0.79. The most important features were the length of the operation, followed by sex (based on biological attributes), age, and operation start time. The logistic regression model and the SVM showed worse results, with an AUC of 0.71 each., Conclusions: This study demonstrated a novel approach to predicting conversion to inpatient status in eligible patients for ambulatory surgery. The XGBoost model showed good predictive capabilities, superior to the older machine learning approaches. This model also revealed the importance of surgical duration time, BMI, and age as risk factors for patient conversion. A developing field of study is using machine learning in clinical decision-making. Our findings contribute to this field by demonstrating the feasibility and accuracy of such methods in predicting outcomes and identifying risk factors, although external and multi-center validation studies are needed., Competing Interests: Declaration of Competing Interest One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objectives: To develop a three-stage convolutional neural network (CNN) approach to segment anatomical structures, classify the presence of lumbar spinal stenosis (LSS) for all 3 stenosis types: central, lateral recess and foraminal and assess its severity on spine MRI and to demonstrate its efficacy as an accurate and consistent diagnostic tool., Methods: The three-stage model was trained on 1635 annotated lumbar spine MRI studies consisting of T2-weighted sagittal and axial planes at each vertebral level. Accuracy of the model was evaluated on an external validation set of 150 MRI studies graded on a scale of absent, mild, moderate or severe by a panel of 7 radiologists. The reference standard for all types was determined by majority voting and in case of disagreement, adjudicated by an external radiologist. The radiologists' diagnoses were then compared to the diagnoses of the model., Results: The model showed comparable performance to the radiologist average both in terms of the determination of presence/absence of LSS as well as severity classification, for all 3 stenosis types. In the case of central canal stenosis, the sensitivity, specificity and AUROC of the CNN were (0.971, 0.864, 0.963) for binary (presence/absence) classification compared to the radiologist average of (0.786, 0.899, 0.842). For lateral recess stenosis, the sensitivity, specificity and AUROC of the CNN were (0.853, 0.787, 0.907) compared to the radiologist average of (0.713, 0.898, 805). For foraminal stenosis, the sensitivity, specificity and AUROC of the CNN were (0.942, 0.844, 0.950) compared to the radiologist average of (0.879, 0.877, 0.878). Multi-class severity classifications showed similarly comparable statistics., Conclusions: The CNN showed comparable performance to radiologist subspecialists for the detection and classification of LSS. The integration of neural network models in the detection of LSS could bring higher accuracy, efficiency, consistency, and post-hoc interpretability in diagnostic practices., (© 2023. The Author(s).)

To date, biplanar imaging (2D) has been the method of choice for pedicle screw (PS) positioning and verified for the anteroposterior view and (spinal midline) M-line method. In recent years, the use of intraoperative three-dimensional (3D) imaging has become available with the Gertzbein-Robbins system (GRS) to assess PS breach and positioning confirmation. The aim is to determine if 2D imaging is sufficient to assess PS position in comparison to advanced 3D imaging.Retrospective review of prospectively collected data from 204 consecutive adult patients who underwent posterior thoracic and lumbar instrumented fusion for degenerative spinal surgery by a single surgeon (2019-2022).Of the 204 patients, 187 (91.6%) had intraoperative images available for analysis. A total of 1044 PS implants were used; 922 (88.3%) were robotically placed. Postoperative CT scans were verified with M-line/GRS findings. Among 103 patients (50.5%) with a total of 362 screws, (34.7%) had postoperative CT, intraoperative 3D scan, and intraoperative 2D scan for analysis. Postoperative CT findings were consistent with all GRS findings, validating that 3D imaging was accurate. Screws (1%) were falsely verified by the M-line as 3D imaging confirmed false negative or positive findings.In our series, intraoperative 3D scan was as accurate as postoperative CT scan in assessing PS breach. A significant number of PS may be falsely read as accurate on 2D imaging, that is in fact inaccurate when assessed on 3D imaging. An intraoperative post-instrumentation 3D scan may be preferable to prevent postoperative recognition of a falsely verified screw on biplanar imaging., (© 2024. The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.)

Study Design: Human Cadaveric Study., Objective: This study aims to explore the feasibility of using preoperative magnetic resonance imaging (MRI), zero-time-echo (ZTE) and spoiled gradient echo (SPGR), as source data for robotic-assisted spine surgery and assess the accuracy of pedicle screws., Methods: Zero-time-echo and SPGR MRI scans were conducted on a human cadaver. These images were manually post-processed, producing a computed tomography (CT)-like contrast. The Mazor X robot was used for lumbar pedicle screw-place navigating of MRI. The cadaver underwent a postoperative CT scan to determine the actual position of the navigated screws., Results: Ten lumbar pedicle screws were robotically navigated of MRI (4 ZTE; 6 SPGR). All MR-navigated screws were graded A on the Gertzbein-Robbins scale. Comparing preoperative robotic planning to postoperative CT scan trajectories: The screws showed a median deviation of overall 0.25 mm (0.0; 1.3), in the axial plane 0.27 mm (0.0; 1.3), and in the sagittal plane 0.24 mm (0.0; 0.7)., Conclusion: This study demonstrates the first successful registration of MRI sequences, ZTE and SPGR, in robotic spine surgery here used for intraoperative navigation of lumbar pedicle screws achieving sufficient accuracy, showcasing potential progress toward radiation-free spine surgery., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

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

Background: The modified frailty index (mFI-5) has been shown to be a reliable risk stratification tool in different spine procedures. Its usefulness to predict complications after 1-level or 2-level anterior cervical decompression and fusion (ACDF) has not been studied extensively., Purpose: We aimed to assess the usefulness of the mFI-5 in 1-level or 2-level ACDF surgery by asking the following questions: (1) Is the mFI-5 a reliable tool to predict complications after 1-level or 2-level ACDF? (2) Is the mFI-5 useful in predicting prolonged hospital stay after 1-level or 2-level ACDF? (3) Is the mFI-5 useful in predicting readmission after 1-level or 2-level ACDF?, Methods: We performed a retrospective analysis of the medical records of patients who underwent 1-level or 2-level ACDF at our institution. The mFI-5 was calculated based on the presence of 5 comorbidities: (1) congestive heart failure, (2) diabetes mellitus, (3) chronic obstructive pulmonary disease, (4) partially or totally dependent functional status, and (5) hypertension requiring medication. Patients were classified in 3 groups: not frail (mFI-5 items = 0), pre-frail (mFI-5 items = 1), and frail (mFI-5 items ≥2). Postoperative complications, length of stay, and readmission were recorded., Results: In the 662 patients included (mean age 51.4 ± 10.4 years), surgical and medical complications were not significantly different among groups. Lengths of stay and readmission rates were both significantly higher in the pre-frail group., Conclusion: Our study findings suggest that the mFI-5 might not be reliable to assess preoperative risk after 1-level or 2-level ACDF., Competing Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Gbolabo Sokunbi, MD, reports relationships with Stryker and Camber Spine. Alexander P. Hughes, MD, reports relationships with Kuros Biosciences AG, NuVasive, Inc., and Kuros Biosciences BV. Federico P. Girardi, MD, reports relationships with Lanx, Inc., Ortho Development Corp., BCIMD, and Healthpoint Capital Partners, LP. Frank P. Cammisa, MD, reports relationships with NuVasive, Inc., Accelus, 4WEB Medical/4WEB, Inc., Healthpoint Capital Partners, LP; ISPH II, LLC; ISPH 3 Holdings, LLC; Ivy Healthcare Capital Partners, LLC; Medical Device Partners II, LLC; Medical Device Partners III, LLC; Orthobond Corporation; Spine Biopharma, LLC; Tissue Differentiation Intelligence, LLC; VBVP VI, LLC; VBVP X, LLC; Woven Orthopedics Technologies; DePuy Synthes, Spine Biopharma, LLC, Mallinckrodt Pharmaceuticals, Camber Spine, and Centinel Spine. Andrew. A. Sama, MD, reports relationships with Ortho Development, Corp., Vestia Ventures MiRUS Investment, LLC, IVY II, LLC, ISPH II, LLC, ISPH 3, LLC, HSS ASC Development Network, LLC, Centinel Spine (Vbros Venture Partners V), Depuy Synthes Products, Inc., Clariance, Inc., Kuros Biosciences AG, Ortho Development Corp., and Spinal Kinetics, Inc. The other authors declared no potential conflicts of interest., (© The Author(s) 2024.)

Study Design: A randomized, double-blinded, placebo-controlled trial., Objective: To examine the effect of intravenous ketorolac (IV-K) on hospital opioid use compared with IV-placebo (IV-P) and IV acetaminophen (IV-A)., Summary of Background Data: Controlling postoperative pain while minimizing opioid use after lumbar spinal fusion is an important area of study., Patients and Methods: Patients aged 18 to 75 years undergoing 1 to 2 level lumbar fusions between April 2016 and December 2019 were included. Patients with chronic opioid use, smokers, and those on systemic glucocorticoids or contraindications to study medications were excluded. A block randomization scheme was used, and study personnel, hospital staff, and subjects were blinded to the assignment. Patients were randomized postoperatively. The IV-K group received 15 mg (age > 65) or 30 mg (age < 65) every six hours (q6h) for 48 hours, IV-A received 1000 mg q6h, and IV-P received normal saline q6h for 48 hours. Demographic and surgical details, opioid use in morphine milliequivalents, opioid-related adverse events, and length of stay (LOS) were recorded. The primary outcome was in-hospital opioid use up to 72 hours., Results: A total of 171 patients were included (58 IV-K, 55 IV-A, and 58 IV-P) in the intent-to-treat (ITT) analysis, with a mean age of 57.1 years. The IV-K group had lower opioid use at 72 hours (173 ± 157 mg) versus IV-A (255 ± 179 mg) and IV-P (299 ± 179 mg; P = 0.000). In terms of opiate use, IV-K was superior to IV-A ( P = 0.025) and IV-P ( P = 0.000) on ITT analysis, although on per-protocol analysis, the difference with IV-A did not reach significance ( P = 0.063). When compared with IV-P, IV-K patients reported significantly lower worst ( P = 0.004), best ( P = 0.001), average ( P = 0.001), and current pain ( P = 0.002) on postoperative day 1, and significantly shorter LOS ( P = 0.009) on ITT analysis. There were no differences in opioid-related adverse events, drain output, clinical outcomes, transfusion rates, or fusion rates., Conclusions: By reducing opioid use, improving pain control on postoperative day 1, and decreasing LOS without increases in complications or pseudarthrosis, IV-K may be an important component of "enhanced recovery after surgery" protocols., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Objectives: Symptomatic lumbar spinal stenosis (LSS) leads to functional impairment and pain. While radiologic characterization of the morphological stenosis grade can aid in the diagnosis, it may not always correlate with patient symptoms. Artificial intelligence (AI) may diagnose symptomatic LSS in patients solely based on self-reported history questionnaires., Methods: We evaluated multiple machine learning (ML) models to determine the likelihood of LSS using a self-reported questionnaire in patients experiencing low back pain and/or numbness in the legs. The questionnaire was built from peer-reviewed literature and a multidisciplinary panel of experts. Random forest, lasso logistic regression, support vector machine, gradient boosting trees, deep neural networks, and automated machine learning models were trained and performance metrics were compared., Results: Data from 4827 patients (4690 patients without LSS: mean age 62.44, range 27-84 years, 62.8% females, and 137 patients with LSS: mean age 50.59, range 30-71 years, 59.9% females) were retrospectively collected. Among the evaluated models, the random forest model demonstrated the highest predictive accuracy with an area under the receiver operating characteristic curve (AUROC) between model prediction and LSS diagnosis of 0.96, a sensitivity of 0.94, a specificity of 0.88, a balanced accuracy of 0.91, and a Cohen's kappa of 0.85., Conclusions: Our results indicate that ML can automate the diagnosis of LSS based on self-reported questionnaires with high accuracy. Implementation of standardized and intelligence-automated workflow may serve as a supportive diagnostic tool to streamline patient management and potentially lower health care costs., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: Pre-operative lumbar spine MRI is usually acquired with the patient supine, whereas lumbar spine surgery is most commonly performed prone. For MRI to be used reliably and safely for intra-operative navigation for foraminal and extraforaminal decompression, the magnitude of dorsal root ganglion (DRG) displacement between supine and prone positions needs to be understood., Methods: A prospective study of a degenerative lumbar spine cohort of 18 subjects indicated for lumbar spine surgery. Three-dimensional T2-weighted fast spin echo and T1-weighted spoiled gradient echo sequences were acquired at 3 T. Displacement and cross-sectional area (CSA) of the bilateral DRGs at 5 motion levels (L1-2 to L5-S1) were determined via 3D segmentation by 2 independent evaluators. Wilcoxon rank-sum tests without correction for multiple comparison were performed against hypothesized 1-mm absolute displacement and corresponding 24% CSA change., Results: DRG mean absolute displacement was <1 mm (p > 0.99, mean = 0.707 mm, 95% confidence interval (CI) = 0.659 to 0.755 mm), with the largest directional displacement in the dorsal-to-ventral direction from supine to prone (mean = 0.141 mm, 95% CI = 0.082 to 0.200 mm). Directional displacements caudal-to-cephalad were 0.087 mm (95% CI = 0.022 to 0.151 mm), and left-right were -0.030 mm (95%CI = -0.059 to -0.001 mm). Mean CSA change was within 24% (p > 0.99, mean = -8.30%, 95% CI = -10.5 to -6.09%). Mean absolute displacement was largest for the L1 (mean = 0.811 mm) and L2 (mean = 0.829 mm) DRGs., Conclusions: Minimal, non-statistically significant soft tissue displacement and morphological area differences were demonstrated between supine and prone positions during 3D lumbar spine MRI., Competing Interests: Declaration of Competing Interest Drs. Lebl, Sneag, and Tan received research support from Medtronic, Inc., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Purpose: The goals were to ascertain if differences in imaging/clinical characteristics between women and men were associated with differences in fusion for lumbar degenerative spondylolisthesis., Methods: Patients had preoperative standing radiographs, CT scans, and intraoperative fluoroscopic images. Symptoms and comorbidity were obtained from patients; procedure (fusion-surgery or decompression-alone) was obtained from intraoperative records. With fusion surgery as the dependent variable, men and women were compared in multivariable logistic regression models with clinical/imaging characteristics as independent variables. The sample was dichotomized, and analyses were repeated with separate models for men and women., Results: For 380 patients (mean age 67, 61% women), women had greater translation, listhesis angle, lordosis, and pelvic incidence, and less diastasis and disc height (all p ≤ 0.03). The rate of fusion was higher for women (78% vs. 65%; OR 1.9, p = 0.008). Clinical/imaging variables were associated with fusion in separate models for men and women. Among women, in the final multivariable model, less comorbidity (OR 0.5, p = 0.05), greater diastasis (OR 1.6, p = 0.03), and less anterior disc height (OR 0.8, p = 0.0007) were associated with fusion. Among men, in the final multivariable model, opioid use (OR 4.1, p = 0.02), greater translation (OR 1.4, p = 0.0003), and greater diastasis (OR 2.4, p = 0.0002) were associated with fusion., Conclusions: There were differences in imaging characteristics between men and women, and women were more likely to undergo fusion. Differences in fusion within groups indicate that decisions for fusion were based on composite assessments of clinical and imaging characteristics that varied between men and women., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This study aimed to compare screw accuracy and incidence of skive between two robotically navigated instrumented techniques in posterior spine fusion surgery: manual anti-skive instrumentation with an anti-skive cannula (ASC) and the use of a navigated, high-speed drill (HSD). Over a 3-year period, consecutive patients are undergoing RNA posterior fusion surgery with either ASC (n = 53) or HSD (n = 63). Both groups met a value of approximately 292 screws in our analysis (296 ASC, 294 HSD), which was determined by a biostatistician at an academic institution. Screw accuracy and skive was analyzed using preoperative CT and intraoperative three-dimensional (3D) fluoroscopy. Among 590 planned robotically inserted pedicle screws (296 ASC, 294 HSD), 245 ASC screws (82.8%) and 283 HSD screws (96.3%) were successfully inserted (p < 0.05). Skive events occurred in 4/283 (1.4%) HSD screws and 15/245 (6.2%) ASC screws (p < 0.05). HSD screws showed better accuracy in the axial and sagittal planes, being closer to planned trajectories in all directions except cranial deviation (p < 0.05). Additionally, HSD had a significantly lower time per screw (1.9 ± 1.0 min) compared to ASC (3.2 ± 2.0 min, p < 0.001). No adverse clinical effects were observed. The HSD technique showed significant improvements in time and screw accuracy compared to ASC. Biplanar fluoroscopy and 3D imaging resulted in significantly lower radiation exposure and time compared to ASC. These significant findings in the HSD group may be attributed to the lower occurrence of malpositioned screws, leading to a decrease in the need for second authentication. This represents a notable iterative improvement of the RNA platform., (© 2023. The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.)

Study Design/setting: A retrospective observational study., Objective: The aim of this study was to investigate the factors associated with the conversion of patient status from ambulatory anterior cervical discectomy and fusion (ACDF) to inpatient., Summary of Background Data: Surgeries are increasingly performed in an ambulatory setting in an era of rising healthcare costs and pressure to improve patient satisfaction. ACDF is a common ambulatory cervical spine surgery, however, there are certain patients who are unexpectedly converted from an outpatient procedure to inpatient admission and little is known about the risk factors for conversion., Materials and Methods: Patients who underwent one-level or two-level ACDF in an ambulatory setting at a single specialized orthopedic hospital between February 2016 to December 2021 were included. Baseline demographics, surgical information, complications, and conversion reasons were compared between patients with ambulatory surgery or observational stay (stay <48 h) and inpatient (stay >48 h)., Results: In total, 662 patients underwent one-level or two-level ACDF (median age, 52 yr; 59.5% were male), 494 (74.6%) patients were discharged within 48 hours and 168 (25.4%) patients converted to inpatient. Multivariable logistic regression analysis demonstrated that females, low body mass index <25, American Society of Anesthesiologists classification (ASA) ≥3, long operation, high estimated blood loss, upper-level surgery, two-level fusion, late operation start time, and high postoperative pain score were considered independent risk factors for conversion to inpatient. Pain management was the most common reason for the conversion (80.0%). Ten patients (1.5%) needed reintubation or remained intubated for airway management., Conclusions: Several independent risk factors for prolonged hospital stay after ambulatory ACDF surgery were identified. Although some factors are unmodifiable, other factors, such as procedure duration, operation start time, and blood loss could be potential targets for intervention. Surgeons should be aware of the potential for life-threatening airway complications in ambulatory-scheduled ACDF., Competing Interests: A.A.S. reports royalties from Ortho Development Corp.; private investments for Vestia Ventures MiRUS Investment LLC, IVY II LLC, ISPH II LLC, ISPH 3 LLC, HSS ASC Development Network LLC, and Centinel Spine (Vbros Venture Partners V); consulting fee from Depuy Synthes Products Inc., Clariance Inc., Kuros Biosciences AG, Ortho Development Corp., Medical Device Business Service Inc.; speaking and teaching arrangements of DePuy Synthes Products Inc.; membership of scientific advisory board of Depuy Synthes Products Inc., Clariance Inc., and Kuros Biosciences AG; Medical Device Business Service Inc.; and trips/travel of Medical Device Business; research support from Spinal Kinetics Inc., outside the submitted work. F.P.C. reports royalties from NuVasive Inc., Accelus; ownership interest for 4WEB Medical/4WEB Inc.; Healthpoint Capital Partners, LP; ISPH II LLC; ISPH 3 Holdings LLC; Ivy Healthcare Capital Partners LLC; Medical Device Partners II LLC; Medical Device Partners III LLC; Orthobond Corporation; Spine Biopharma LLC; Tissue Differentiation Intelligence LLC; VBVP VI LLC; VBVP X LLC; Woven Orthopedics Technologies; consulting fees from 4WEB Medical/4WEB Inc., DePuy Synthes, NuVasive Inc., Spine Biopharma LLC, and Synexis LLC, Accelus; membership of scientific advisory board/other office of Healthpoint Capital Partners, Medical Device Partners II LLC, Orthobond Corporation, Spine Biopharma LLC, and Woven Orthopedic Technologies; and research support from 4WEB Medical/4WEB Inc., Mallinckrodt Pharmaceuticals, Camber Spine, and Centinel Spine, outside the submitted work. F.P.G. reports royalties from Lanx Inc., and Ortho Development Corp.; private investments for BCIMD; and stock ownership of Healthpoint Capital Partners LP, outside the submitted work. A.P.H. reports research support from Kuros Biosciences AG; and fellowship support from NuVasive Inc. and Kuros Biosciences BV, outside the submitted work. The remaining authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Lateral lumbar interbody fusion (LLIF) is a minimally invasive surgical approach used to treat a variety of degenerative and deformity conditions of the lumbar spine such as advanced degenerative disease, degenerative scoliosis, foraminal and central stenosis. It has emerged as an alternative to the traditional posterior and anterior lumbar approaches with some potential benefits such as lower blood loss and shorter hospital stay. In this article, we provide our single institutional surgical experience including main indications and contraindications, a step-by-step surgical technique description, a detailed preoperative imaging assessment with a focus on magnetic resonance imaging (MRI) psoas anatomy, operative room (OR) setup and patient positioning. A descriptive surgical technical note of the following steps is provided: positioning and fluoroscopic confirmation, incision and intraoperative level confirmation, discectomy and endplate preparation, implant size selection and insertion and final fluoroscopic control, hemostasis check and wound closure along with an instructional surgical video with tips and pearls, postoperative patient care recommendations, common approach-related complications, along with our historical clinical institutional group experience. Finally, we summarize our research experience in this surgical approach with a focus on LLIF as a standalone procedure. Based on our experience, LLIF can be considered an effective surgical technique to treat degenerative lumbar spine conditions. Proper patient selection is mandatory to achieve good outcomes. Our institutional experience shows higher fusion rates with good clinical outcomes and a relatively low rate of complications., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-23-54/coif). AAS reports royalties from Ortho Development, Corp.; private investments for Vestia Ventures MiRUS Investment, LLC, ISPH II, LLC, ISPH 3, LLC, HS2, LLC, HSS ASC Development Network, LLC and VBros Venture Partners X Centinel Spine; consulting fee from Clariance, Inc., Kuros Biosciences AG, DePuy Synthes Products, Inc., Ortho Development Corp and Medical Device Business Service, Inc.; speaking and teaching arrangements of DePuy Synthes Products, Inc.; membership of scientific advisory board of Clariance, Inc., and Kuros Biosciences AG; and trips/travel of Medical Device Business; research support from Spinal Kinetics, Inc., outside the submitted work. FPC reports royalties from NuVasive, Inc. and Accelus; private investments for 4WEB Medical/4WEB, Inc., Healthpoint Capital Partners, LP, ISPH II, LLC, ISPH 3 Holdings, LLC, Ivy Healthcare Capital Partners, LLC, Medical Device Partners II, LLC, Medical Device Partners III, LLC, Orthobond Corporation, Spine Biopharma, LLC, Tissue Differentiation Intelligence, LLC, VBVP VI, LLC, VBVP X, LLC (Centinel) and Woven Orthopedics Technologies; consulting fees from 4WEB Medical/4WEB, Inc., Accelus; DePuy Synthes Spine, NuVasive, Inc. and Spine Biopharma, LLC; membership of scientific advisory board/other office of Healthpoint Capital Partners, LP, Medical Device Partners III, LLC, Orthobond Corporation, Spine Biopharma, LLC, and Woven Orthopedic Technologies; and research support from 4WEB Medical/4WEB, Inc., Mallinckrodt Pharmaceuticals, Camber Spine, and Centinel Spine; scientific support from Healthpoint Capital Partners, LP; outside the submitted work. FPG reports royalties from Lanx, Inc., and Ortho Development Corp.; private investments for Centinel Spine, and BCMID; stock ownership of Healthpoint Capital Partners, LP; and consulting fees from NuVasive, Inc., and DePuy Synthes Spine, outside the submitted work. APH reports research support from Expanding Innovations, Inc. and Kuros Biosciences BV; and fellowship support from NuVasive, Inc. and Kuros Biosciences BV, outside the submitted work. DRL reports royalties from NuVasive, Inc. and Stryker; private investments from HS2, LLC, Woven Orthopedic Technologies, Vestia Ventures MiRus Investiment LLC, ISPH, LLC; consulting fee from Depuy Synthes, Vizeon, Inc.; scientific advisory board from Remedy Logic; and research support from Medtronic. GS receives consulting fees from Stryker and Camber spine. The other authors have no conflicts of interest to declare., (2023 Journal of Spine Surgery. All rights reserved.)

Study Design: Retrospective database analysis., Objective: To elucidate trends in the utilization of intraoperative neurophysiological monitoring (IONM) during elective lumbar surgery procedures and to investigate the association between the use of IONM and surgical outcomes., Background: The routine use of IONM in elective lumbar spine procedures has recently been called into question due to longer operative time, higher cost, and other substitute advanced technologies., Methods: The Statewide Planning and Research Cooperative System database was accessed to perform this retrospective study. The trends of IONM use for lumbar decompression and fusion procedures were investigated from 2007 to 2018. The association between IONM use and surgical outcomes was investigated from 2017 to 2018. Multivariable logistic regression analyses, as well as propensity score matching (PS-matching), were conducted to assess IONM association in neurological deficits reduction., Results: The utilization of IONM showed an increase in a linear fashion from 79 cases in 2007 to 6201 cases in 2018. A total of 34,592 (12,419 monitored and 22,173 unmonitored) patients were extracted, and 210 patients (0.6%) were reported for postoperative neurological deficits. Unadjusted comparisons demonstrated that the IONM group was associated with significantly fewer neurological complications. However, the multivariable analysis indicated that IONM was not a significant predictor of neurological injuries. After the PS-matching of 23,642 patients, the incidence of neurological deficits was not significantly different between IONM and non-IONM patients., Conclusion: The utilization of IONM for elective lumbar surgeries continues to gain popularity. Our results indicated that IONM use was not associated with a reduction in neurological deficits and will not support the routine use of IONM for all elective lumbar surgery., Competing Interests: A.A.S. reports royalties from Ortho Development, Corp.; private investments for Vestia Ventures MiRUS Investment, LLC, ISPH II, LLC, ISPH 3, LLC, and VBros Venture Partners X Centinel Spine; consulting fee from Clariance, Inc., Kuros Biosciences AG, and Medical Device Business Service, Inc.; speaking and teaching arrangements of DePuy Synthes Products, Inc.; membership of scientific advisory board of Clariance, Inc., and Kuros Biosciences AG; and trips/travel of Medical Device Business research support from Spinal Kinetics, Inc., outside the submitted work. F.P.C. reports royalties from NuVasive, Inc.; private investments for 4WEB Medical/4WEB, Inc., Accelus, Bonovo Orthopedics, Inc., Healthpoint Capital Partners, LP, ISPH II, LLC, ISPH 3 Holdings, LLC, Ivy Healthcare Capital Partners, LLC, Medical Device Partners II, LLC, Medical Device Partners III, LLC, Orthobond Corporation, Spine Biopharma, LLC, Synexis, LLC, Tissue Differentiation Intelligence, LLC, VBVP VI, LLC, VBVP X, LLC (Centinel) and Woven Orthopedics Technologies; consulting fees from 4WEB Medical/4WEB, Inc., DePuy Synthes Spine, NuVasive, Inc., Spine Biopharma, LLC, and Synexis, LLC; membership of scientific advisory board/other office of Healthpoint Capital Partners, LP, Medical Device Partners III, LLC, Orthobond Corporation, Spine Biopharma, LLC, Synexis, LLC, and Woven Orthopedic Technologies; and research support from 4WEB Medical/4WEB, Inc., Mallinckrodt Pharmaceuticals, Camber Spine, and Centinel Spine, outside the submitted work. F.P.G. reports royalties from Lanx, Inc., and Ortho Development Corp.; private investments for Centinel Spine, and BCMID; stock ownership of Healthpoint Capital Partners, LP; and consulting fees from NuVasive, Inc., and DePuy Synthes Spine, outside the submitted work. A.P.H. reports research support from NuVasive, Inc. and Kuros Biosciences AG; and fellowship support from NuVasive, Inc. and Kuros Biosciences AG, outside the submitted work. D.R.L. reports royalties from NuVasive, Inc and Stryker; private investments from HS2, LLC, Woven Orthopedic Technologies, Vestia Ventures MiRus Investiment LLC, ISPH, LLC; consulting fee from Depuy Synthes, Vizeon, Inc; scientific advisory board from Remedy Logic; and research support from Medtronic. The remaining authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Context: Many individuals at high risk for fracture are never evaluated for osteoporosis and subsequently do not receive necessary treatment. Utilization of magnetic resonance imaging (MRI) is burgeoning, providing an ideal opportunity to use MRI to identify individuals with skeletal deficits. We previously reported that MRI-based bone texture was more heterogeneous in postmenopausal women with a history of fracture compared to controls., Objective: The present study aimed to identify the microstructural characteristics that underlie trabecular texture features., Methods: In a prospective cohort, we measured spine volumetric bone mineral density (vBMD) by quantitative computed tomography (QCT), peripheral vBMD and microarchitecture by high-resolution peripheral QCT (HRpQCT), and areal BMD (aBMD) by dual-energy x-ray absorptiometry. Vertebral trabecular bone texture was analyzed using T1-weighted MRIs. A gray level co-occurrence matrix was used to characterize the distribution and spatial organization of voxelar intensities and derive the following texture features: contrast (variability), entropy (disorder), angular second moment (ASM; uniformity), and inverse difference moment (IDM; local homogeneity)., Results: Among 46 patients (mean age 64, 54% women), lower peripheral vBMD and worse trabecular microarchitecture by HRpQCT were associated with greater texture heterogeneity by MRI-higher contrast and entropy (r ∼ -0.3 to 0.4, P < .05), lower ASM and IDM (r ∼ +0.3 to 0.4, P < .05). Lower spine vBMD by QCT was associated with higher contrast and entropy (r ∼ -0.5, P < .001), lower ASM and IDM (r ∼ +0.5, P < .001). Relationships with aBMD were less pronounced., Conclusion: MRI-based measurements of trabecular bone texture relate to vBMD and microarchitecture, suggesting that this method reflects underlying microstructural properties of trabecular bone. Further investigation is required to validate this methodology, which could greatly improve identification of patients with skeletal fragility., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Postoperative MRI of the lumbar spine is a mainstay for detailed anatomic assessment and evaluation of complications related to decompression and fusion surgery. Key factors for reliable interpretation include clinical presentation of the patient, operative approach, and time elapsed since surgery. Yet, recent spinal surgery techniques with varying anatomic corridors to approach the intervertebral disc space and implanted materials have expanded the range of normal (expected) and abnormal (unexpected) postoperative changes. Modifications of lumbar spine MRI protocols in the presence of metallic implants, including strategies for metal artifact reduction, provide important diagnostic information. This focused review discusses essential principles for the acquisition and interpretation of MRI after lumbar spinal decompression and fusion surgery, highlights expected postoperative changes, and describes early and delayed postoperative complications with examples., (© RSNA, 2023.)

Background: Frailty status has been associated with higher rates of complications after spine surgery. However, frailty patients constitute a heterogeneous group based on the combinations of comorbidities. The objective of this study is to compare the combinations of variables that compose the modified 5-factor frailty index score (mFI-5) based on the number of comorbidities in terms of complications, reoperation, readmission, and mortality after spine surgery., Methods: The American College of Surgeons - National Surgical Quality Improvement Program (ACS-NSQIP) Database from 2009-2019 was used to identify patients who underwent elective spine surgery. The mFI-5 item score was calculated and patients were classified according to number and combination of comorbidities. Multivariable analysis was used to assess the independent impact of each combination of comorbidities in the mFI-5 score on the risk of complications., Results: A total of 167, 630 patients were included with a mean age of 59.9 ± 13.6 years. The risk of complications was the lowest in patients with diabetes + hypertension (OR = 1.2) and highest in those with the combination of congestive heart failure (CHF), diabetes, chronic obstructive pulmonary disease (COPD), and dependent status (OR = 6.6); there was a high variation in complication rate based on specific combinations., Conclusions: There is high variability in terms of relative risk of complications based on the number and combination of different comorbidities, especially with CHF and dependent status. Therefore, frailty status encompasses a heterogeneous group and sub-stratification of frailty status is necessary to identify patients with significantly higher risk of complications., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Study Design: A retrospective observational study., Objective: The objective of this study was to investigate the factors associated with the conversion of patient status from ambulatory surgery (AMS) to observation service (OS) (<48 h) or inpatient (>48 h)., Summary of Background Data: AMS is becoming increasingly common in the United States because it is associated with a similar quality of care compared with inpatient surgery, significant costs reduction, and patients' desire to recuperate at home. However, there are instances when AMS patients may be subjected to extended hospital stays. Unanticipated extension of hospitalization stays can be a great burden not only to patients but to medical providers and insurance companies alike., Materials and Methods: Data from 1096 patients who underwent one-level or two-level lumbar decompression AMS at an in-hospital, outpatient surgical facility between January 1, 2019, and March 16, 2020, were collected. Patients were categorized into three groups based on length of stay: (1) AMS, (2) OS, or (3) inpatient. Demographics, comorbidities, surgical information, and administrative information were collected. Simple and multivariable logistic regression analyses were conducted comparing AMS patients and OS/inpatient as well as OS and inpatients., Results: Of the 1096 patients, 641 (58%) patients were converted to either OS (n=486) or inpatient (n=155). The multivariable analysis demonstrated that age (more than 80 yr old), high American Society of Anesthesiologists Physical Status (ASA) grade, history of sleep apnea, drain use, high estimated blood loss, long operation, late operation start time, and a high pain score were considered independent risk factors for AMS conversion to OS/inpatient. The risk factors for OS conversion to inpatient were an ASA class 3 or higher, coronary artery disease, diabetes mellitus, hypothyroidism, steroid use, drain use, dural tear, and laminectomy., Conclusions: Several surgical factors along with patient-specific factors were significantly associated with AMS conversion. Addressing modifiable surgical factors might reduce the AMS conversion rate and be beneficial to patients and facilities., Competing Interests: A.A.S. reports royalties from Ortho Development Corp.; private investments for Vestia Ventures MiRUS Investment LLC, ISPH II LLC, ISPH 3 LLC, and VBros Venture Partners X Centinel Spine; consulting fee from Clariance Inc., Kuros Biosciences AG, and Medical Device Business Service Inc.; speaking and teaching arrangements of DePuy Synthes Products Inc.; membership of the scientific advisory board of Clariance Inc., and Kuros Biosciences AG; and trips/travel of Medical Device Business research support from Spinal Kinetics Inc., outside the submitted work. F.P.C. reports royalties from NuVasive Inc.; private investments for 4WEB Medical/4WEB Inc., Accelus, Bonovo Orthopedics Inc., Healthpoint Capital Partners, LP, ISPH II LLC, ISPH 3 Holdings LLC, Ivy Healthcare Capital Partners LLC, Medical Device Partners II LLC, Medical Device Partners III LLC, Orthobond Corporation, Spine Biopharma LLC, Synexis LLC, Tissue Differentiation Intelligence LLC, VBVP VI LLC, VBVP X LLC (Centinel) and Woven Orthopedics Technologies; consulting fees from 4WEB Medical/4WEB Inc., DePuy Synthes Spine, NuVasive Inc., Spine Biopharma LLC, and Synexis LLC; membership of scientific advisory board/other office of Healthpoint Capital Partners, LP, Medical Device Partners III LLC, Orthobond Corporation, Spine Biopharma LLC, Synexis LLC, and Woven Orthopedic Technologies; and research support from 4WEB Medical/4WEB Inc., Mallinckrodt Pharmaceuticals, Camber Spine, and Centinel Spine, outside the submitted work. F.P.G. reports royalties from Lanx Inc., and Ortho Development Corp.; private investments for Centinel Spine, and BCMID; stock ownership of Healthpoint Capital Partners, LP; and consulting fees from NuVasive Inc., and DePuy Synthes Spine, outside the submitted work. A.P.H. reports research support from NuVasive Inc. and Kuros Biosciences AG; and fellowship support from NuVasive Inc. and Kuros Biosciences AG, outside the submitted work. D.R.L. reports royalties from NuVasive Inc. and Stryker; private investments from HS2 LLC, Woven Orthopedic Technologies, Vestia Ventures MiRus Investiment LLC, ISPH LLC; consulting fee from Depuy Synthes, Vizeon Inc.; scientific advisory board from Remedy Logic; and research support from Medtronic. The remaining authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Frailty status and hypoalbuminemia have been associated with higher rates of complications after spine surgery. However, the combination of both conditions has not been fully analyzed. The objective of this study was to assess the effect of frailty and hypoalbuminemia on the risk of complications after spine surgery., Methods: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database from 2009 to 2019 was used. Frailty status was calculated using the modified 5-item frailty index (mFI-5). Patients were classified into nonfrail (mFI = 0), pre-frail (mFI = 1), and frail (mFI ≥2) groups and also based on albumin levels into normal (≥3.5 g/dL) and hypoalbuminemia groups (<3.5 g/dL). The latter group was also subclassified into mild and severe hypoalbuminemia groups. Multivariable analysis was used. A Spearman ρ correlation between albuminemia and mFI-5 was also performed., Results: A total of 69,519 patients (36,705 men [52.8%] and 32,814 women [47.2%]) with a mean age of 61.0 ± 13.2 years were included. Patients were classified as nonfrail (n = 24,897), pre-frail (n = 28,897), and frail groups (n = 15,725). Hypoalbuminemia was significantly higher in the frail group (11.4%) compared with the nonfrail group (4.3%). An inverse correlation was observed between albumin levels and frailty status (ρ = -0.139; P < 0.0001). Frail patients with severe hypoalbuminemia had significantly higher risk of complications (odds ratio [OR], 5.0), reoperation (OR, 3.3), readmission (OR, 3.1), and mortality (OR, 31.8) compared with patients without hypoalbuminemia., Conclusions: The combination of frailty and hypoalbuminemia significantly increases the risk of complications after spine surgery. The prevalence of hypoalbuminemia in the frailty group was significantly higher than in nonfrail patients (11.4% vs. 4.3%). Both conditions should be evaluated preoperatively., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Purpose: There are reports that performing lateral lumbar interbody fusion (LLIF) in a prone, single position (single-prone LLIF) can be done safely in the prone position because the retroperitoneal organs reflect anteriorly with gravity. However, only a few study has investigated the safety of single-prone LLIF and retroperitoneal organ positioning in the prone position. We aimed to investigate the positioning of retroperitoneal organs in the prone position and evaluate the safety of single-prone LLIF surgery., Methods: A total of 94 patients were retrospectively reviewed. The anatomical positioning of the retroperitoneal organs was evaluated by CT in the preoperative supine and intraoperative prone position. The distances from the centre line of the intervertebral body to the organs including aorta, inferior vena cava, ascending and descending colons, and bilateral kidneys were measured for the lumbar spine. An "at risk" zone was defined as distance less than 10 mm anterior from the centre line of the intervertebral body., Results: Compared to supine preoperative CTs, bilateral kidneys at the L2/3 level as well as the bilateral colons at the L3/4 level had statistically significant ventral shift with prone positioning. The proportion of retroperitoneal organs within the at-risk zone ranged from 29.6 to 88.6% in the prone position., Conclusions: The retroperitoneal organs shifted ventrally with prone positioning. However, the amount of shift was not large enough to avoid risk for organ injuries and substantial proportion of patients had organs within the cage insertion corridor. Careful preoperative planning is warranted when considering single-prone LLIF., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Low back pain (LBP) is a common cause of disability worldwide; multiple causes and risk factors have been proposed in the genesis of back pain. Some studies reported an association between diastasis recti abdominis (DRA), a surrogate for decreased core strength muscle, and low back pain. We aimed to investigate the relationship between DRA and LBP through a systematic review., Methods: A systematic review of the literature of clinical studies in English literature was conducted. PubMed, Cochrane, and Embase databases were used to conduct the search up to January 2022. The strategy included the following keywords: "Lower Back Pain" AND "Diastasis Recti" OR "Rectus abdominis" OR "abdominal wall" OR "paraspinal musculature"., Results: From 207 records initially found, 34 were suitable for full review. Thirteen studies were finally included in this review, with a total of 2,820 patients. Five studies found a positive association between DRA and LBP (5 of 13 = 38.5%) whereas 8 studies did not find any association between DRA and LBP (8 of 13 = 61.5%)., Conclusions: Of the studies included in this systematic review, 61.5% did not find an association between DRA and LBP whereas a positive correlation was observed in 38.5% of studies included. Based on the quality of the studies included in our review, better studies are warranted to understand the association between DRA and LBP., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The aim of this study was to assess the accuracy of pedicle screw placement, as well as intraoperative factors, radiation exposure, and complication rates in adult patients with degenerative disorders of the thoracic and lumbar spines who have undergone robotic-navigated spinal surgery using a contemporary system. The authors reviewed the prospectively collected data on 196 adult patients who had pedicle screws implanted with robot-navigated assistance (RNA) using the Mazor X Stealth system between June 2019 and March 2022. Pedicle screws were implanted by one experienced spinal surgeon after completion of a learning period. The accuracy of pedicle screw placement was determined using intraoperative 3D fluoroscopy. A total of 1,123 pedicle screws were implanted: 1,001 screws (89%) were placed robotically, 63 (6%) were converted from robotic placement to a freehand technique, and 59 (5%) were planned to be implanted freehand. Of the robotically placed screws, 942 screws (94%) were determined to be Gertzbein and Robbins grade A with median deviation of 0.8 mm (interquartile range 0.4 to 1.6). Skive events were noted with 20 pedicle screws (1.8%). No adverse clinical sequelae were noted in the 90-day follow-up. The mean fluoroscopic exposure per screw was 4.9 seconds (SD 3.8). RNA is highly accurate and reliable, with a low rate of abandonment once mastered. No adverse clinical sequelae occurred after implanting a large series of pedicle screws using the latest generation of RNA. Understanding of patient-specific anatomical features and the real-time intraoperative identification of risk factors for suboptimal screw placement have the potential to improve accuracy further., Competing Interests: None declared., (© 2023 The British Editorial Society of Bone & Joint Surgery.)

Background: Assessing the impact of spine disorders such as lumbar degenerative spondylolisthesis (LDS) on overall health is a component of quality of care that may not be comprehensively captured by spine-specific and single-attribute patient-reported outcome measures (PROMs). Purpose : We sought to compare PROMs to the Lumbar Surgery Expectations Survey ("Expectations Survey"), which addresses multiple aspects of health and well-being, and to compare the relevance of surgeon-selected versus survey-selected Patient-Reported Outcomes Measurement Information System (PROMIS) items to LDS. Methods : In a cross-sectional study, 379 patients with LDS preoperatively completed the Expectations Survey, Numerical Rating Pain Scales, Oswestry Disability Index (ODI), and PROMIS computer-adaptive physical function, pain, and mental health surveys. Expectations Survey scores were compared to PROMs with correlation coefficients (indicating strengths of relationships) and probability values (indicating associations by chance). Surgeons reviewed physical function questions to identify those particularly relevant to LDS. Results : Patients' mean age was 67 years, 64% were women, and 83% had single-level and 17% had multiple-level LDS. Probability values between the Expectations Survey and PROMs were reliable, but strengths of relationships were only mild to moderate, indicating PROMs did not comprehensively capture the impact of LDS. None of the surgeon-selected PROMIS physical function questions were posed to patients. Conclusion : This cross-sectional study found PROMs to be reliably associated but not strongly correlated with the Expectations Survey, which addresses the whole-patient impact of LDS. New measures that complement PROMIS and ODI should be developed to capture the whole-person effects of LDS and permit attribution of LDS treatments to overall health., Competing Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Frank P. Cammisa, MD, reports relationships with 4Web Medical/4WEB, Bonovo Orthopedics, Camber Spine, Centinel Spine, DuPuy Synthes, Health Point Capital Partners, Integrity Implants, ISPH, Ivy Healthcare Capital Partners, Medical Device Partners, National Basketball Association, NuVasive, Orthobond, Spine Biopharma LLC, Synexis, Tissue Differentiation Intelligence, VBVP VI, VBVP X, and Woven Orthopedic Technologies. Andrew A. Sama, MD, reports relationships with Centinel Spine, Clarience, DePuy Synthes, ISPH II, ISPH 3, Kuros Biosciences, Medical Device Business Services, OrthoDevelopment, Spinal Kinetics, VBros Venture Partners, and Vestia Ventures MiRus Investment. Alexander P. Hughes, MD, reports relationships with Kuros Biosciences, Kuros Biosurgery, and Nuvasive. Darren R. Lebl, MD, reports relationships with HS2, Nuvasive, Remedy Logic, Stryker, Vestia Ventures MiRus Investment, Viseon, and Woven Orthopedic Technologies. Harvinder S. Sandhu, MD, reports relationships with Paradigm Spine, Prosydian, Providence Medical Tech, SeaSpine, and Spinewave. Federico P. Girardi, MD, reports relationships with DePuy Synthes, Ethicon, Healthpoint Capital Partners, Nuvasive, Ortho Development, and Spineart USA. The other authors report no potential conflicts of interest., (© The Author(s) 2023.)

Background Context: Fulfillment of expectations is a patient-centered outcome that has not been assessed based on fusion status for lumbar degenerative spondylolisthesis (LDS)., Purpose: To compare preoperatively cited expectations and 2-year postoperative fulfillment of expectations between patients undergoing decompression alone (no-fusion) vs. decompression plus fusion (fusion) for LDS., Study Design: Longitudinal cohort., Patient Sample: A total of 357 patients., Outcome Measures: Postoperative version of Lumbar Spine Surgery Expectations Survey, Oswestry Disability Index (ODI), satisfaction with surgery., Methods: Preoperatively patients completed the 20-item Expectations Survey measuring amount of 'improvement expected' for symptoms, physical function, and psychosocial well-being (score range 0-100); two years postoperatively patients completed the follow-up survey measuring 'improvement received'. The proportion of expectations fulfilled was calculated as 'improvement received' divided by 'improvement expected' (<1 some expectations fulfilled, >1 expectations surpassed). Patients also completed the ODI, SF-12 mental health subscale, satisfaction with surgery, and measures of comorbidity and psychosocial status, including social support (ie, help at home) and prior orthopedic surgery (ie, hip/knee arthroplasty)., Results: Patients' mean age was 67 years, 61% were women, 82% had single-level LDS, 73% had fusion, and mean follow-up was 26.2 months. Compared to patients with no-fusion, patients with fusion had more pain, spinal instability, use of opioids, disability, and greater preoperative Expectations Survey scores (69 vs 74, p=.008). The proportion of expectations fulfilled postoperatively was high and similar for both groups (.82 vs. .79, p=.40), but more variable for fusion (IQR .32 vs. .40). In multivariable analysis with the proportion as the dependent variable, fulfilled expectations was associated with better mental well-being (coeff=1.1, 95% CI 0.6-1.7, p=.0001) and more social support (coeff=3.3, 95% CI 1.1-5.6, p=.004) and unfulfilled expectations was associated with prior arthroplasty (coeff=-8.6, 95% CI -15.4-(-1.9), p=.01) and subsequent lumbar surgery (coeff=-15.6, 95% CI -25.2-(-6.0), p=.002). Similar associations were found for change in ODI and satisfaction., Conclusions: Patients had high preoperative expectations of surgery with greater expectations for decompression-fusion compared to decompression-alone. Although more variable for the fusion group, both groups had high proportions of expectations fulfilled. This study highlights the spectrum of clinical and psychosocial variables that impacts fulfillment of expectations for both decompression-alone and decompression-fusion for LDS surgery., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Across many of the surgical specialties, the use of minimally invasive techniques that utilize indirect visualization has been increasingly replacing traditional techniques which utilize direct visualization. Arthroscopic surgery of the appendicular skeleton has evolved dramatically and become an integral part of musculoskeletal surgery over the last several decades, allowing surgeons to achieve similar or better outcomes, while reducing cost and recovery time. However, to date, the axial skeleton, with its close proximity to critical neural and vascular structures, has not adopted endoscopic techniques at as rapid of a rate. Over the past decade, increased patient demand for less invasive spine surgery combined with surgeon desire to meet these demands has driven significant evolution and innovation in endoscopic spine surgery. In addition, there has been an enormous advancement in technologies that assist in navigation and automation that help surgeons circumvent limitations of direct visualization inherent to less invasive techniques. There are currently a multitude of endoscopic techniques and approaches that can be utilized in the treatment of spine disorders, many of which are evolving rapidly. Here we present a review of the field of endoscopic spine surgery, including the background, techniques, applications, current trends, and future directions, to help providers gain a better understanding of this growing modality in spine surgery., Competing Interests: Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article., (©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.)

Spine fusion surgery is one of the most common orthopedic procedures, with over 400,000 performed annually to correct deformities and pain. However, complications occur in approximately one third of cases. While many of these complications may be related to poor bone quality, it is difficult to detect bone abnormalities prior to surgery. Areal BMD (aBMD) assessed by DXA may be artifactually high in patients with spine pathology, leading to missed diagnosis of deficits. In this study, we related preoperative imaging characteristics of both central and peripheral sites to direct measurements of bone quality in vertebral biopsies. We hypothesized that pre-operative imaging outcomes would relate to vertebral bone mineralization and collagen properties. Pre-operative assessments included DXA measurements of aBMD of the spine, hip, and forearm, central quantitative computed tomography (QCT) of volumetric BMD (vBMD) at the lumbar spine, and high resolution peripheral quantitative computed tomography (HRpQCT; Xtreme CT2) measurements of vBMD and microarchitecture at the distal radius and tibia. Bone samples were collected intraoperatively from the lumbar vertebrae and analyzed using Fourier-transform Infrared (FTIR) spectroscopy. Bone samples were obtained from 23 postmenopausal women (mean age 67 ± 7 years, BMI 28 ± 8 kg/m 2 ). We found that patients with more mature bone by FTIR, measured as lower acid phosphate content and carbonate to phosphate ratio, and greater collagen maturity and mineral maturity/crystallinity (MMC), had greater cortical vBMD at the tibia and greater aBMD at the lumbar spine and one-third radius. Our data suggests that bone quality at peripheral sites may predict bone quality at the spine. As bone quality at the spine is challenging to assess prior to surgery, there is a great need for additional screening tools. Pre-operative peripheral bone imaging may provide important insight into vertebral bone quality and may foster identification of patients with bone quality deficits., Competing Interests: Declaration of competing interest AKH, AD, BES, LS, SG, KBA, AJ, SC, and EB have nothing to disclose. HJK reports personal fees from Alphatec, personal fees from K2M, personal fees from Zimmerbiomet, outside the submitted work. MC reports grants and personal fees from K2M, personal fees from Zimmerbiomet, grants from Radius Health, grants from RTI, outside the submitted work. DL reports. Consultant role for Depuy Synthes, Stryker, Viseon, Inc., ownership interest in HS2,LLC, ISPH II,LLC, Remedy Logic, Vestia Ventures MiRus Investment LLC, Woven Orthopedic Technologies, Viseon, Inc.; royalty fees from Nuvasive, Inc., Stryker; Advisory Board membership for Remedy Logic (all activities outside the submitted work). ED has nothing to disclose. EMS reports grants from Novartis, grants from Radius Health, all outside the submitted work., (Copyright © 2023 Elsevier Inc. All rights reserved.)