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Study Design: Reliability study., Objectives: The radiographic diagnosis of non-union is not standardized. Prior authors have suggested using a cutoff of <1 mm interspinous process motion (ISPM) on flexion-extension radiographs, but the ability of practicing surgeons to make these measurements reliably is not clear., Methods: 29 practicing spine surgeons measured ISPM on 19 levels of ACDF from 9 patients. Surgeons relied on these measurements to report on fusion status. Inter-observer correlation co-efficients (ICC), standard error (SEM) and the minimum detectable difference (MD) of these measurements were calculated. We screened for clerical errors by checking measurements more than one standard deviation from the group mean., Results: The ICC for ISPM was .76 (.64; .88) with a SEM of 1 mm and a MD of 2.76 mm. Agreement on fusion status was moderate, with an ICC of .6 (.44; .76). After screening for and removing clerical errors, the ICC improved to .82 (.71; .91), SEM improved to .83 mm, and MD improved to 2.29 mm. Six reviewers had an ICC >.9. The ICC from these high performing reviewers was .94 (.9; .97), SEM was .45 mm, and MD was 1.26 mm., Conclusions: The MD of 2.29 mm in our study group was not precise enough to support a cutoff of <1 mm ISPM as the sole measurement technique in screening for non-union after ACDF, and there was only moderate agreement amongst surgeons on fusion status based on dynamic radiographs. More stringent techniques are necessary to avoid mis-diagnosing non-union in clinical studies. Future studies should consider auditing measurements to identify clerical errors., 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.

Background: Closed, unstable AO/OTA 44B2 ankle fractures are common injuries with similar distributions by age, sex, and race. The purpose of this study was to identify disparities in access to and utilization of surgical care for these injuries., Methods: Ambulatory patients ≥18 years of age with capitated Medicaid health insurance who presented from January 2016 to February 2020 with an isolated, closed AO/OTA 44B2 ankle fracture with radiographic evidence of instability were retrospectively identified at 1 Level-I safety-net trauma center. Associations between patient characteristics (age, sex, preferred language, race, ethnicity, housing status, employment, and substance use) and measures of access to and utilization of ankle fracture surgery (days from injury to evaluation, being offered surgery, undergoing surgery, and days from evaluation to surgery) were investigated on bivariable and multivariable analysis., Results: Of the 1,116 patients who were screened, 323 met the inclusion criteria. The included patients had a median age of 41 years; 207 patients (64%) were male and 255 (79%) were Hispanic. Patients presented at a mean of 4.6 ± 7.0 days from injury. Delayed presentation was associated with self-identification as Hispanic (rate ratio [RR], 1.93; 95% confidence interval [CI]: 1.17, 3.12]) and with marijuana use (RR, 1.59; 95% CI: 1.08, 2.36), whereas significantly earlier presentation was associated with a non-English language preference (RR, 0.64; 95% CI: 0.46, 0.89), alcohol abuse (RR, 0.74; 95% CI: 0.55, 0.99), and illicit drug use (RR, 0.30; 95% CI: 0.14, 0.67). Ankle fracture surgery was offered to 274 patients (85%). Experiencing homelessness was associated with a decreased likelihood of being offered surgery (odds ratio [OR], 0.15; 95% CI: 0.03, 0.69). Of patients who were offered surgery, 216 (79%) underwent surgery. Black patients underwent surgery significantly less frequently than patients who identified as White (OR, 0.14; 95% CI: 0.01, 0.77). The median time from evaluation to surgery was 11 days (interquartile range, 7 to 14 days). Patients who used illicit drugs experienced a mean delay to surgery of 6.0 days relative to those who did not use illicit drugs (mean time to surgery, 16.8 ± 7.1 and 10.8 ± 5.1 days, respectively)., Conclusions: We identified disparities in access to and utilization of surgical care for unstable AO/OTA 44B2 ankle fractures that negatively affected patients with Medicaid insurance who identified as Hispanic or Black, were experiencing homelessness, or used illicit drugs. These disparities may negatively affect outcomes for patients receiving care in similar environments, such as capitated health-care networks and public safety-net health systems., Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: This study and the Article Processing Charge for open access publication were funded by a Young Investigator Research Development Award from AO Trauma North America. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSOA/A717)., (Copyright © 2024 The Authors. Published by The Journal of Bone and Joint Surgery, Incorporated. All rights reserved.)

Objective: The purpose of this study is to describe utilization, demographics, complications, and revisions for patients with degenerative spondylolisthesis (DS) with stenosis undergoing decompression or decompression with fusion in the United States., Methods: A national insurance database was used to identify patients who underwent either decompression and fusion or decompression alone for management of DS from 2010-2022. Utilization trends, demographics, and complications for each procedure were compared., Results: A total of 162,878 patients were identified, of which 78,043 patients underwent combined single-level lumbar decompression and fusion and 84,835 underwent single-level lumbar decompression alone. Between 2010-2021, lumbar decompression and fusion became the predominant surgical intervention for DS in 2016 and continued to account for more than half of all procedures during the remainder of the study period. Factors such as age, sex, comorbidities, geographic region, and physician specialty training were associated with procedure choice. Decompression with fusion was associated with a lower risk of revision surgery up to 5 years postoperatively and an overall lower incidence of 30-day complications., Conclusion: Decompression with fusion has become the most common treatment for lumbar DS over the past decade despite a lack of compelling evidence supporting its use compared to decompression alone. A variety of patient and surgeon-specific factors is associated with procedure choice. After accounting for cofounders, we identified treatment-specific complications that may be valuable when counseling patients.

Study Design: Systematic review and meta-analysis., Objective: To compare radiographic outcomes across lumbar interbody fusion (LIF) techniques, assessing segmental and global lumbar lordosis restoration., Summary of Background Data: LIF is a commonly utilized procedure to treat various spinal conditions, including degenerative pathology and adult spinal deformity. Common approaches include posterior LIF (PLIF), transforaminal LIF (TLIF), anterior LIF (ALIF), oblique LIF (OLIF), and lateral LIF (LLIF)., Methods: A systematic review and meta-analysis were carried out using PRISMA guidelines with appropriate MeSH terms. Papers were included based on relevance, number of patients, and a minimum of 1-year radiographic follow-up. Radiographic outcomes included segmental lordosis (SL) and lumbar lordosis (LL). Only papers directly comparing SL restoration between two or more LIF techniques were utilized in the systematic review, while all articles meeting the aforementioned criteria were used in the meta-analysis., Results: Nineteen studies were included in the final systematic review, and 88 papers were included in the meta-analysis. Seven studies in the systematic review showed a significantly higher increase in SL with ALIF versus TLIF, and two showed significantly higher SL gain with ALIF compared with LLIF. When comparing ALIF versus OLIF, one study favored ALIF, while another favored OLIF for SL restoration. OLIF likewise demonstrated superior restoration of SL compared with TLIF. LLIF demonstrated improved SL restoration compared with TLIF in 2 of the 3 studies comparing the 2 procedures. Furthermore, both ALIF and OLIF demonstrated superior LL restoration compared with TLIF in 4 and 3 studies, respectively. The meta-analysis results demonstrated that ALIF provided significantly better restoration of SL than TLIF, LLIF, and OLIF, while TLIF conferred significantly lower SL restoration than ALIF and OLIF. Similarly, LL restoration was significantly reduced with TLIF relative to OLIF and LLIF (all P <0.05)., Conclusions: The included studies demonstrated superior SL and LL restoration with ALIF, OLIF, and LLIF compared with TLIF. ALIF improved SL to a greater extent when directly compared with all other interbody techniques., Competing Interests: J.C.W. has received intellectual property royalties from Zimmer Biomet, NovApproach, SeaSpine, and DePuy Synthes. R.J.H. has received grant funding from SI Bone, consulting fees from NuVasive, and support from the North American Spine Society to attend meetings. R.K.A. has received grant funding from NIH, consulting fees from HIA Technologies, and payment from Eccentrial Robotics for lectures and presentations​​​. The remaining authors declare no conflict of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective cohort analysis., Objective: To characterize the impact of COVID-19 on utilization of the ten most common spine procedures and percentages of outpatient procedures., Methods: The PearlDiver national database was queried from January 2010 to April 2021 for short (<6 segments) and long segment posterior instrumented fusion (≥6 segments), posterior cervical fusion, anterior cervical decompression and fusion (ACDF), cervical laminectomy, laminoplasty, and disc arthroplasty, lumbar laminectomy, microdiscectomy, and interbody fusion. Annual procedure utilization between January 2010 through April 2021 was recorded and compared. Monthly trends were compared to January 2020. Outpatient trends were compared between 2010-2019 and 2019-2021 using segmented linear regression., Results: Overall, all ten procedures decreased 4.3% in 2020 compared to 2019 and increased 6.3% in 2021 compared to 2019. March and April of 2020 had the largest decreases, with March 2020 decreasing 18.2% and April 2020 decreasing 51.6% compared to January 2020. Despite increasing COVID cases in January 2021, overall procedure utilization decreased only 1.8% compared to January 2020, and increased later in 2021 with April 2021 case volumes increasing by 138% compared to January 2020. Outpatient utilization of short segment posterior lumbar fusion and lumbar interbody fusion significantly increased during this time ( P < .001)., Conclusion: The greatest impact on spine surgery volume from the COVID-19 pandemic occurred in March and April 2020. Spine procedure utilization was otherwise similar or increased compared to January 2020. Additionally, the volume of outpatient short segment posterior fusion and lumbar interbody fusions increased during this time period., Competing Interests: DisclosuresThe author(s) declare the following disclosures with respect to the research, authorship, and/or publication of this article: Emily S. Mills, Kevin Mertz, Ethan Faye, and Andy Ton has nothing to disclose. Jeffrey C. Wang has received intellectual property royalties from Zimmer Biomet, NovApproach, SeaSpine, and DePuy Synthes. Raymond J. Hah M.D. has received grant funding from SI bone, consulting fees from NuVasive, and support from the North American Spine Society to attend meetings. Ram K. Alluri, M.D. discloses has received grant funding from NIH, consulting fees from HIA Technologies, and payment from Eccentrial Robotics for lectures and presentations. Institutional review board (IRB) approval and informed consent were not required as no patient information was involved in this study.

Study Design: Systematic Review., Objectives: While substantial research has explored the impact of osteoporosis on patients undergoing adult spinal deformity (ASD) correction, the literature remains inconclusive. As such, the purpose of this study is to synthesize and analyze existing studies pertaining to osteoporosis as a predictor of postoperative outcomes in ASD surgery., Methods: We performed a systematic review and meta-analysis to determine the effect that a diagnosis of osteoporosis, based on ICD-10 coding, dual-energy X-ray absorptiometry (DEXA) or computed tomography, has on the incidence of adverse outcomes following surgical correction of ASD. Statistical analysis was performed using Comprehensive Meta-Analysis (Version 2) using a random effects model to account for heterogeneity between studies., Results: After application of inclusion and exclusion criteria, 36 and 28 articles were included in the systematic review and meta-analysis, respectively. The meta-analysis identified greater rates of screw loosening amongst osteoporotic patients (70.5% vs 31.9%, P = .009), and decreased bone mineral density in patients who developed proximal junctional kyphosis (PJK) (.69 vs .79 g/cm 2 , P = .001). The systematic review demonstrated significantly increased risk of any complication, reoperation, and proximal junctional failure (PJF) associated with reduced bone density. No statistical difference was observed between groups regarding fusion rates, readmission rates, and patient-reported and/or functional outcome scores., Conclusion: This study demonstrates a higher incidence of screw loosening, PJK, and revision surgery amongst osteoporotic ASD patients. Future investigations should explore outcomes at various follow-up intervals in order to better characterize how risk changes with time and to tailor preoperative planning based on patient-specific characteristics., 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.

Objective: The present study compares postoperative outcomes between patients with and without sickle cell disease (SCD) undergoing 1-to 3-level lumbar spinal fusion for degenerative pathologies., Methods: Patients who underwent 1-to 3-level lumbar spinal fusion for degenerative pathologies from 2010 to 2021 were identified using the PearlDiver database. Patients were separated into 1) SCD and 2) non-SCD groups and were propensity-matched 1:1 for age, sex, Elixhauser Comorbidity Index, surgical approach, and various comorbidities. Complications were separately analyzed by single- and multilevel procedures using chi-squared and Mann-Whitney U testing., Results: Propensity-score matching identified 1934 SCD and non-SCD patients who underwent single-level fusion and 2094 SCD and non-SCD patients who underwent multilevel fusion. Across single-level fusions, those with SCD had a significantly higher risk of neurovascular compromise (P < 0.001), venous thromboembolism (P = 0.004), pneumonia (P = 0.032), urinary tract infections (P = 0.001), and greater postoperative opioid usage out to 12 months (P = 0.018). Across multilevel fusions, SCD carried higher risk for neurovascular compromise (P < 0.001), pneumonia (P = 0.010), and urinary tract infections (P < 0.001). All SCD patients had significantly higher opioid use at 1 month (P = 0.001) and at 6 months (P = 0.009) postoperatively., Conclusions: Patients with SCD undergoing lumbar spinal fusion demonstrate higher risks for coagulopathic, ischemic, and infectious-related complications, as well as long-term postoperative opioid use. Awareness of the unique complication profile in SCD patients may help guide surgeons in refining perioperative management strategies to optimize outcomes in patients with SCD., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Purpose: The purpose of this cross-sectional, observational study was to establish the relationship between standing lumbar lordosis (LL) and lateral decubitus LL., Methods: Forty-nine subjects, 24 male and 25 female, were prospectively enrolled. Patients with pre-existing spinopelvic pathology were excluded. Standing, relaxed-seated, and lateral decubitus lateral radiographs were obtained. Radiographic variables measured included LL and lordosis change at each lumbar level (e.g. L1-L2). The change in LL when going from a standing to a lateral decubitus position (ΔLL), the correlation between standing and sitting LL compared to lateral decubitus LL, and the correlation between ΔLL and standing pelvic incidence (PI), pelvic tilt (PT), PI-LL mismatch, pelvic femoral angle (PFA), and sacral slope (SS) were calculated., Results: Subjects had an average age of 25.7 ± 2.3 years and body mass index of 24.1 ± 3.0 kg/m 2 . On average, 11.9°±8.2° (range - 7° to 29°) of LL was lost when transitioning from a standing to the lateral decubitus position. Lateral decubitus LL had a higher correlation with standing LL (R = 0.725, p < 0.001) than with relaxed-seated LL (R = 0.434, p < 0.001). Standing PT and PI-LL mismatch had moderately negative correlations with ΔLL (R=-0.58 and R=-0.59, respectively, both p < 0.05). Standing PI and standing PFA had a low negative correlation with ΔLL (R=-0.31 and R=-0.44, respectively, both p < 0.05) Standing SS and LL had no correlation with ΔLL., Conclusions: Standing LL was strongly correlated to lateral decubitus LL, although subjects lost an average of 11.9° from the standing to the lateral decubitus position. This has important implications for fusion in the lateral position., (© 2024. The Author(s).)

Ferroptosis is implicated in viral neuropathogenesis and may underlie HIV-associated neurocognitive impairment (NCI). Emerging data also suggest differences in brain iron transport by sex. We hypothesized that circulating ferritins that inhibit ferroptosis associate with neurocognitive function and NCI in people with HIV (PWH) in a sex-biased manner. Serum ferritin heavy-chain-1 (FTH1), ferritin light-chain (FTL), and urinary F 2 -isoprostanes (uF 2 -isoPs, specific lipid peroxidation marker) were quantified in 324 PWH (including 61 women) with serial global (NPZ-4) and domain-specific neurocognitive testing. Biomarker associations with neurocognitive test scores and NCIs were evaluated by multivariable regression; correlations with uF 2 -isoPs were also assessed. Higher FTL and FTH1 levels were associated with less NCI in all PWH (adjusted odds ratios 0.53, 95% confidence interval (95% CI) 0.36-0.79 and 0.66, 95% CI 0.45-0.97, respectively). In women, higher FTL and FTH1 were also associated with better NPZ-4 (FTL adjusted beta (β) = 0.15, 95% CI 0.02-0.29; FTL-by-sex β interaction = 0.32, p = 0.047) and domain-specific neurocognitive test scores. Effects on neurocognitive performance persisted for up to 5 years. Levels of both ferritins correlated inversely with uF 2 -isoPs in women (FTL: rho = -0.47, p < 0.001). Circulating FTL and FTH1 exert sustained, sex-biased neuroprotective effects in PWH, possibly by protecting against iron-mediated lipid peroxidation (ferroptosis). Larger studies are needed to confirm the observed sex differences and further delineate the underlying mechanisms.

The numerical sense of animals includes identifying the numerosity of a sequence of events that occur with specific intervals, e.g., notes in a call or bar of music. Across nervous systems, the temporal patterning of spikes can code these events, but how this information is decoded (counted) remains elusive. In the anuran auditory system, temporal information of this type is decoded in the midbrain, where "interval-counting" neurons spike only after at least a threshold number of sound pulses have occurred with specific timing. We show that this decoding process, i.e., interval counting, arises from integrating phasic, onset-type and offset inhibition with excitation that augments across successive intervals, possibly due to a progressive decrease in "shunting" effects of inhibition. Because these physiological properties are ubiquitous within and across central nervous systems, interval counting may be a general mechanism for decoding diverse information coded/encoded in temporal patterns of spikes, including "bursts," and estimating elapsed time., Competing Interests: Competing interests statement:The authors declare no competing interest.

Introduction: Vertebral compression fractures (VCFs) pose a considerable healthcare burden and are linked to elevated morbidity and mortality. Despite available anti-osteoporotic treatments (AOTs), guideline adherence is lacking. This study aims to evaluate subsequent hip fracture incidence after index VCF and to elucidate AOT prescribing patterns in VCF patients, further assessing the impact of surgical interventions on these patterns. Materials and Methods: Patients with index VCFs between 2010 and 2021 were identified using the PearlDiver database. Diagnostic and procedural data were recorded using International Classification of Diseases (ICD-9, ICD-10) and Current Procedural Terminology (CPT) codes. Patients under age 50 and follow-up

Background: Risk assessment is critically important in elective and high-risk interventions, particularly spine surgery. This narrative review describes the evolution of risk assessment from the earliest instruments focused on general surgical risk stratification, to more accurate and spine-specific risk calculators that quantified risk, to the current era of big data., Methods: The PubMed and SCOPUS databases were queried on October 11, 2023 using search terms to identify risk assessment tools (RATs) in spine surgery. A total of 108 manuscripts were included after screening with full-text review using the following inclusion criteria: 1) study population of adult spine surgical patients, 2) studies describing validation and subsequent performance of preoperative RATs, and 3) studies published in English., Results: Early RATs provided stratified patients into broad categories and allowed for improved communication between physicians. Subsequent risk calculators attempted to quantify risk by estimating general outcomes such as mortality, but then evolved to estimate spine-specific surgical complications. The integration of novel concepts such as invasiveness, frailty, genetic biomarkers, and sarcopenia led to the development of more sophisticated predictive models that estimate the risk of spine-specific complications and long-term outcomes., Conclusions: RATs have undergone a transformative shift from generalized risk stratification to quantitative predictive models. The next generation of tools will likely involve integration of radiographic and genetic biomarkers, machine learning, and artificial intelligence to improve the accuracy of these models and better inform patients, surgeons, and payers., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: As the elderly population grows, the increasing prevalence of osteoporosis presents a unique challenge for surgeons. Decreased bone strength and quality are associated with hardware failure and impaired bone healing, which may increase the rate of revision surgery and the development of complications. The purpose of this review is to determine the impact of osteoporosis on postoperative outcomes for patients with cervical degenerative disease or deformity., Methods: A systematic review using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and Medical Subject Headings terms involving spine surgery for cervical degenerative disease and osteoporosis were performed. This review focused on radiographic outcomes, as well as surgical and medical complications., Results: There were 16 studies included in the degenerative group and 9 in the deformity group. Across degenerative studies, lower bone mineral density was associated with increased rates of cage subsidence in osteoporotic patients undergoing operative treatment for cervical degenerative disease. Most studies reported varied results on the relationship between osteoporosis and other outcomes such as revision and readmission rates, costs, and perioperative complications. Our meta-analysis suggests that osteoporotic patients carry a greater risk of reduced fusion rates at 6 months and 1 year postoperatively. With respect to cervical deformity correction, although individual complication rates were unchanged with osteoporosis, the collective risk of incurring any complication may be increased in patients with poor bone stock., Conclusions: Overall, the literature suggests that outcomes for osteoporotic patients after cervical spine surgery are multifactorial. Osteoporosis seems to be a significant risk factor for developing cage subsidence and pseudarthrosis postoperatively, whereas reports on medical and hospital-related metrics were inconclusive. Our findings highlight the challenges of caring for osteoporotic patients and underline the need for adequately powered studies to understand how osteoporosis changes the risk index of patients undergoing cervical spine surgery., Clinical Relevance: In patients undergoing cervical spine surgery for degenerative disease, osteoporosis is a significant risk factor for long-term postoperative complications-notably cage subsidence and pseudarthrosis. Given the elective nature of these procedures, interdisciplinary collaboration between providers should be routinely implemented to enable medical optimization of patients prior to cervical spine surgery., 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.)

Objective: We evaluated the contributions of chronological age, comorbidity burden, and/or frailty in predicting 90-day readmission in patients undergoing degenerative scoliosis surgery., Methods: Patients were identified through the Healthcare Cost and Utilization Project Nationwide Readmissions Database. Frailty was assessed using the Johns Hopkins Adjusted Clinical Groups frailty-defining indicator. Comorbidity was assessed using the Elixhauser Comorbidity Index (ECI). Generalized linear mixed-effects models were created to predict readmission using age, frailty, and/or ECI. Area under the curve (AUC) was compared using DeLong's test., Results: A total of 8104 patients were identified. Readmission rate was 9.8%, with infection representing the most common cause (3.5%). Our first model utilized chronological age, ECI, and/or frailty as primary predictors. The combination of ECI + frailty + age performed best, but the inclusion of chronological age did not significantly improve performance compared to ECI + frailty alone (AUC 0.603 vs. 0.599, P = 0.290). A second model using only chronological age and frailty as primary predictors performed better, however the inclusion of chronological age worsened performance when compared to frailty alone (AUC 0.747 vs. 0.743, P = 0.043)., Conclusions: These data support frailty as a predictor of 90-day readmission within a nationally representative sample. Frailty alone performed better than combinations of ECI and age. Interestingly, the integration of chronological age did not dramatically improve the model's performance. Limitations include the use of a national registry and a single frailty index. This provides impetus to explore biological age, rather than chronological age, as a potential tool for surgical risk assessment., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Lumbar spinal pathology is known to affect outcomes following total hip arthroplasty (THA). However, the effect of hip osteoarthritis (OA) on outcomes following lumbar fusion has not been well studied. The purpose of this study was to determine the association between hip OA and spinal reoperation following lumbar spinal fusion., Methods: The 5% Medicare Part B claims database was queried for all patients who underwent primary elective lumbar fusion from 2005 to 2019. Patients were divided into 2 groups: those who underwent elective THA within 1 year after primary lumbar fusion, indicating that they had severe hip OA at the time of lumbar fusion, and those who underwent lumbar fusion with no diagnosed hip OA and no THA during the study period. Exclusion criteria included THA as a result of trauma, revision THA or primary THA in the 5-year period before primary lumbar fusion, <65 years of age, and no enrollment in the database for 5 years before and 1 year after primary lumbar fusion. The primary outcome was spinal reoperation within 1, 3, and 5 years. Multivariable Cox regression was performed with age, sex, diabetes, heart disease, obesity, smoking status, osteoporosis, number of levels fused, use of posterior instrumentation, use of an interbody device, use of bone graft, and surgical approach as covariates., Results: Overall, 1,123 patients (63.4% female; 91.3% White; mean age, 76.8 ± 4.1 years) were included in the hip OA group and 8,893 patients (56.2% female; 91.3% White; mean age, 74.8 ± 4.9 years) were included in the control group. After multivariable analysis, patients with severe hip OA had significantly greater rates of revision surgery at 3 years (odds ratio [OR], 1.61; p < 0.001) and 5 years (OR, 1.87; p < 0.001) after the index lumbar fusion., Conclusions: Patients with severe hip OA at the time of primary lumbar fusion had a significantly increased risk of spinal reoperation at 3 and 5 years postoperatively. These data provide further evidence to support performing THA prior to lumbar fusion in the unsettled debate regarding which surgery should be prioritized for patients with simultaneous degenerative diseases of the hip and lumbar spine., Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: No external funding was received for this work. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJS/I43)., (Copyright © 2024 by The Journal of Bone and Joint Surgery, Incorporated.)

Study Design: Retrospective Cohort Study., Objectives: Cervical radiculopathy and peripheral entrapment neuropathies often have overlapping symptoms that are difficult to distinguish on physical examination. Small-scale studies have attempted to report the incidence of this phenomenon, often called double crush syndrome (DCS), with varying results. The present study aims to determine the incidence of concomitant cervical radiculopathy and peripheral nerve compression and to determine if the DCS hypothesis, which states that compression of a nerve at one site leaves it more susceptible to compression at another, is valid., Methods: The PearlDiver database was queried from 2010 to 2020. The incidence of peripheral neuropathy in cervical radiculopathy was assessed. Propensity score matching was used to determine if patients with cervical radiculopathy were more likely to have peripheral nerve compression compared to controls, and vice versa, to test the DCS hypothesis., Results: The database contains records of 90,772 632 patients. The incidence of carpal tunnel syndrome (CTS) or peripheral ulnar nerve compression (PUnC) in cervical radiculopathy was 9.98% and 3.15%, respectively. The incidence of both carpal tunnel syndrome and PUnC in cervical radiculopathy was 1.84%. Patients with cervical radiculopathy were more likely than matched controls to have both CTS ( P < .001) and PUnC ( P < .001). Patients with CTS ( P < .001) and with PUnC ( P < .001) were more likely to have cervical radiculopathy than the control cohort., Conclusions: The incidence of DCS is reported. Patients with cervical radiculopathy are more likely than matched controls to have peripheral nerve compression, and vice versa, in support of the DCS hypothesis.

Background: There is considerable heterogeneity in findings and a lack of consensus regarding the interplay between osteoporosis and outcomes in patients with lumbar degenerative spine disease. Therefore, the purpose of this systematic review and meta-analysis was to gather and analyze existing data on the effect of osteoporosis on radiographic, surgical, and clinical outcomes following surgery for lumbar degenerative spinal disease., Methods: A systematic review was performed to determine the effect of osteoporosis on the incidence of adverse outcomes after surgical intervention for lumbar degenerative spinal diseases. The approach focused on the radiographic outcomes, reoperation rates, and other medical and surgical complications. Subsequently, a meta-analysis was performed on the eligible studies., Results: The results of the meta-analysis suggested that osteoporotic patients experienced increased rates of adjacent segment disease (ASD; p=0.015) and cage subsidence (p=0.001) while demonstrating lower reoperation rates than non-osteoporotic patients (7.4% vs. 13.1%; p=0.038). The systematic review also indicated that the length of stay, overall costs, rates of screw loosening, and rates of wound and other medical complications may increase in patients with a lower bone mineral density. Fusion rates, as well as patient-reported and clinical outcomes, did not differ significantly between osteoporotic and non-osteoporotic patients., Conclusions: Osteoporosis was associated with an increased risk of ASD, cage migration, and possibly postoperative screw loosening, as well as longer hospital stays, incurring higher costs and an increased likelihood of postoperative complications. However, a link was not established between osteoporosis and poor clinical outcomes.

Background: In recent years, the use of intraoperative computer tomography-guided (CT-guided) navigation has gained significant popularity among health care providers who perform minimally invasive spine surgery. This review aims to identify and analyze trends in the literature related to the widespread adoption of CT-guided navigation in spine surgery, emphasizing the shift from conventional fluoroscopy-based techniques to CT-guided navigation., Methods: Articles pertaining to this study were identified via a database review and were hierarchically organized based on the number of citations. An "advanced document search" was performed on September 28th, 2022, utilizing Boolean search operator terms. The 25 most referenced articles were combined into a primary list after sorting results in descending order based on the total number of citations., Results: The "Top 25" list for intraoperative CT-guided navigation in spine surgery cumulatively received a total of 2742 citations, with an average of 12 new citations annually. The number of citations ranged from 246 for the most cited article to 60 for the 25th most cited article. The most cited article was a paper by Siewerdsen et al., with 246 total citations, averaging 15 new citations per year., Conclusions: Intraoperative CT-guided navigation is 1 of many technological advances that is used to increase surgical accuracy, and it has become an increasingly popular alternative to conventional fluoroscopy-based techniques. Given the increasing adoption of intraoperative CT-guided navigation in spine surgery, this review provides impactful evidence for its utility in spine surgery., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Robot-guided lumbar spine surgery has evolved rapidly with evidence to support its utility and feasibility compared with conventional freehand and fluoroscopy-based techniques. The objective of this study was to assess trends among the top 25 most-cited articles pertaining to robotic-guided lumbar spine surgery., Methods: An "advanced document search" using Boolean search operator terms was performed on 16 November 2022 through the Web of Science and SCOPUS citation databases to determine the top 25 most-referenced articles on robotic lumbar spine surgery. The articles were compiled into a directory and hierarchically organized based on the total number of citations., Results: Cumulatively, the "Top 25" list for robot-assisted navigation in lumbar spine surgery received 2240 citations, averaging 97.39 citations annually. The number of citations ranged from 221 to 40 for the 25 most-cited articles. The most-cited study, by Kantelhardt et al, received 221 citations, averaging 18 citations per year., Conclusions: As utilization of robot-guided modalities in lumbar spine surgery increases, this review highlights the most impactful studies to support its efficacy and implementation. Practical considerations such as cost-effectiveness, however, need to be better defined through further longitudinal studies that evaluate patient-reported outcomes and cost-utility., Clinical Relevance: Through an overview of the top 25 most-cited articles, the present review highlights the rising prominence and technical efficacy of robotic-guided systems within lumbar spine surgery, with consideration to pragmatic limitations and need for additional data to facilitate cost-effective applications., 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: Systematic review., Objectives: Spin in scientific literature is defined as bias that overstates efficacy and/or underestimates harms of procedures undergoing review. While lumbar microdiscectomies (MD) are considered the gold standard for treating lumbar disc herniations (LDH), outcomes of novel procedures are being weighed against open MD. This study identifies the quantity and type of spin in systematic reviews and meta-analyses of LDH interventions., Methods: A search was conducted on the PubMed, Scopus, and SPORTDiscus databases for systematic reviews and meta-analyses evaluating the outcomes of MD against other LDH interventions. Each included study's abstract was assessed for the presence of the 15 most common types of spin, with full texts reviewed during cases of disagreement or for clarification. Full texts were used in the assessment of study quality per AMSTAR 2., Results: All 34 included studies were observed to have at least 1 form of spin, in either the abstract or full text. The most common type of spin identified was type 5 ("The conclusion claims the beneficial effect of the experimental treatment despite a high risk of bias in primary studies"), which was observed in ten studies (10/34, 29.4%). There was a statistically significant association between studies not registered with PROSPERO and the failure to satisfy AMSTAR type 2 ( P < .0001)., Conclusion: Misleading reporting is the most common category of spin in literature related to LDH. Spin overwhelmingly tends to go in the positive direction, with results inappropriately favoring the efficacy or safety of an experimental intervention., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Frank A. Petrigliano has received consulting fees from Stryker, Exactech, Micromed, Smith and Nephew, Zimmer Biomet, Flexion Therapeutics, and Depuy Synthes. Joseph N. Liu has received consulting fees from Stryker, Smith and Nephew, Mertz North America Inc., and Neuracrine Biosciences. Liu also serves as a board member to American Shoulder and Elbow Surgeons and Arthroscopy Association of North America. Ram K. Alluri receives stock options for MiRus and HIA and is a consultant for MiRus and prior consultant for Eccential. Alluri is also a board member for HIA and is deputy editor of Global Spine Journal.

Background: This review outlines clinical data and characteristics of current Food and Drug Administration (FDA)-approved implants in cervical disc replacement/cervical disc arthroplasty (CDR/CDA) to provide a centralized resource for spine surgeons., Methods: Randomized controlled trials (RCTs) on CDR/CDA were identified using a search of the PubMed, Web of Science, and Google Scholar databases. The initial search identified 69 studies. Duplicates were removed, and the following inclusion criteria were applied when determining eligibility of RCTs for the current review: (1) discussing CDR/CDA prosthesis and (2) published within between 2010 and 2020. Studies without clinical data or that were not RCTs were excluded. All articles were reviewed independently by 2 authors, with the involvement of an arbitrator to facilitate consensus on any discrepancies., Results: A total of 34 studies were included in the final review. Findings were synthesized into a comprehensive table describing key features and clinical results for each FDA-approved CDR/CDA implant and are overall suggestive of expanding indications and increasing utilization., Conclusions: RCTs have provided substantial evidence to support CDR/CDA for treating single- and 2-level cervical degenerative disc disease in place of conventional anterior cervical discectomy and fusion., Clinical Relevance: This review provides a resource that consolidates relevant clinical data for current FDA-approved implants to help spine surgeons make an informed decision during preoperative planning., Competing Interests: Declaration of Conflicting Interests : No funding was received for this study. Djani Robertson, Andy Ton, Michael Brown, Shane Shahrestani, and Emily S. Mills have nothing to disclose. Jeffrey C. Wang has received intellectual property royalties from Zimmer Biomet, NovApproach, SeaSpine, and DePuy Synthes. Raymond J. Hah has received grant funding from SI bone, consulting fees from NuVasive, and support from the North American Spine Society to attend meetings. Ram K. Alluri has received grant funding from NIH, consulting fees from HIA Technologies, and payment from Eccentrial Robotics for lectures and presentations., (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.)

A computational neuromuscular control system that generates lung pressure and three intrinsic laryngeal muscle activations (cricothyroid, thyroarytenoid, and lateral cricoarytenoid) to control the vocal source was developed. In the current study, LeTalker , a biophysical computational model of the vocal system was used as the physical plant. In the LeTalker , a three-mass vocal fold model was used to simulate self-sustained vocal fold oscillation. A constant/ǝ/vowel was used for the vocal tract shape. The trachea was modeled after MRI measurements. The neuromuscular control system generates control parameters to achieve four acoustic targets (fundamental frequency, sound pressure level, normalized spectral centroid, and signal-to-noise ratio) and four somatosensory targets (vocal fold length, and longitudinal fiber stress in the three vocal fold layers). The deep-learning-based control system comprises one acoustic feedforward controller and two feedback (acoustic and somatosensory) controllers. Fifty thousand steady speech signals were generated using the LeTalker for training the control system. The results demonstrated that the control system was able to generate the lung pressure and the three muscle activations such that the four acoustic and four somatosensory targets were reached with high accuracy. After training, the motor command corrections from the feedback controllers were minimal compared to the feedforward controller except for thyroarytenoid muscle activation., Competing Interests: Conflicts of Interest: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

Background: Previously reported estimates of vertebral artery injuries (VAIs) during cervical spine surgery relied on self-reported survey studies and retrospective cohorts, which may not be reflective of national averages. The largest study to date reports an incidence of 0.07%; however, significant variation exists between different cervical spine procedures. This study aimed to identify the incidence of VAIs in patients undergoing cervical spine procedures for degenerative pathologies., Methods: In this retrospective cohort study, a national insurance database was used to access data from the period 2010-2020 of patients who underwent anterior cervical discectomy and fusion, anterior corpectomy, posterior cervical fusion (C3-C7), or C1-C2 posterior fusion for degenerative pathologies. Patients who experienced a VAI were identified, and frequencies for the different procedures were compared., Results: This study included 224,326 patients, and overall incidence of VAIs across all procedures was 0.03%. The highest incidence of VAIs was estimated in C1-C2 posterior fusion (0.12%-1.10%). The number of patients with VAIs after anterior corpectomy, anterior cervical discectomy and fusion, and posterior fusion was 14 (0.06%), 43 (0.02%), and 26 (0.01%), respectively., Conclusions: This is the largest study to date to our knowledge that provides frequencies of VAIs in patients undergoing cervical spine surgery in the United States. The overall incidence of 0.03% is lower than previously reported estimates, but significant variability exists between procedures, which is an important consideration when counseling patients about risks of surgery., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Study Design: Retrospective cohort study., Objective: The purpose of this study was to characterize the infection risk of preoperative epidural steroid injection (ESI) in patients undergoing posterior cervical surgery., Summary of Background Data: ESI is a helpful tool for alleviating pain and is often used as a diagnostic tool before cervical surgery. However, a recent small-scale study found that ESI before cervical fusion was associated with an increased risk of postoperative infection., Materials and Methods: Patients from 2010 to 2020 with cervical myelopathy, spondylosis, and radiculopathy who underwent posterior cervical procedure including laminectomy, laminoforaminotomy, fusion, or laminoplasty were queried from the PearlDiver database. Patients who underwent revision or fusion above C2 or who had a diagnosis of neoplasm, trauma, or preexisting infection were excluded. Patients were divided on whether they received an ESI within 30 days before the procedure and subsequently matched by age, sex, and preoperative comorbidities. The χ 2 analysis was used to calculate the risk of postoperative infection within 90 days. Logistic regression controlling for age, sex, Elixhauser Comorbidity Index, and operated levels was conducted within the unmatched population to assess infection risk for injected patients across procedure subgroups., Results: Overall, 299,417 patients were identified with 3897 having received a preoperative ESI and 295,520 who did not. Matching resulted in 975 in the injected group and 1929 in the control group. There was no significant difference in postoperative infection rate in those who received an ESI within 30 days preoperatively and those who did not (3.28% vs. 3.78%, odds ratio=0.86, 95% CI: 0.57-1.32, P =0.494). Logistic regression accounting for age, sex, Elixhauser Comorbidity Index, and levels operated demonstrated that injection did not significantly increase infection risk in any of the procedure subgroups., Conclusions: The present study found no association between preoperative ESI within 30 days before surgery and postoperative infection in patients undergoing posterior cervical surgery., Competing Interests: R.J.H. has received grant funding from SI bone, consulting fees from NuVasive, and support from the North American Spine Society to attend meetings. R.K.A. has received grant funding from NIH, consulting fees from HIA Technologies, and payment from Eccentrial Robotics for lectures and presentations. The remaining authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

The successful operative management of spinal infections necessitates a thoughtful approach. Ideal treatment combines the universal goals of any spine operation, which are decompression of the neural elements and stabilization of instability, with source control and eradication of infection. Techniques to treat infection have evolved independently and alongside advances in implant technology and surgical techniques. This review will seek to outline current thinking on approaches to both primary and secondary spinal infections., Competing Interests: One or more of the authors declare financial or professional relationships on ICMJE-NASSJ disclosure forms., (© 2023 The Author(s).)

Bluehead wrasses (Thalassoma bifasciatum) follow a socially controlled mechanism of sex determination. A socially dominant initial-phase (IP) female is able to transform into a new terminal-phase (TP) male if the resident TP male is no longer present. TP males display an elaborate array of courtship behaviors, including both color changes and motor behaviors. Little is known concerning the neural circuits that control male-typical courtship behaviors. This study used glutamate iontophoresis to identify regions that may be involved in courtship. Stimulation of the following brain regions elicited diverse types of color change responses, many of which appear similar to courtship color changes: the ventral telencephalon (supracommissural nucleus of the ventral telencephalon [Vs], lateral nucleus of the ventral telencephalon [Vl], ventral nucleus of the ventral telencephalon [Vv], and dorsal nucleus of the ventral telencephalon [Vd]), parts of the preoptic area (NPOmg and NPOpc), entopeduncular nucleus, habenular nucleus, and pretectal nuclei (PSi and PSm). Stimulation of two regions in the posterior thalamus (central posterior thalamic [CP] and dorsal posterior thalamic [DP]) caused movements of the pectoral fins that are similar to courtship fluttering and vibrations. Furthermore, these responses were elicited in female IP fish, indicating that circuits for sexual behaviors typical of TP males exist in females. Immunohistochemistry results revealed regions that are more active in fish that are not courting: interpeduncular nucleus, red nucleus, and ventrolateral thalamus (VL). Taken together, we propose that the telencephalic-habenular-interpeduncular pathway plays an important role in controlling and regulating courtship behaviors in TP males; in this model, in response to telencephalic input, the habenular nucleus inhibits the interpeduncular nucleus, thereby dis-inhibiting forebrain regions and promoting the expression of courtship behaviors., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Study Design: Retrospective chart review., Objective: Identify demographic and sagittal alignment parameters that are independently associated with femoral nerve position at the L4-L5 disk space., Summary of Background Data: Iatrogenic femoral nerve or lumbar plexus injury during lateral lumbar interbody fusion (LLIF) can result in neurological complications. The LLIF "safe zone" is the anterior half to two third of the disk space. However, femoral nerve position varies and is inconsistently identifiable on magnetic resonance imaging. The safe zone is also narrowest at L4-L5., Methods: An analysis of patients with symptomatic lumbar spine pathology and magnetic resonance imaging with a visibly identifiable femoral nerve evaluated at a single large academic spine center from January 1, 2017, to January 8, 2020, was performed. Exclusion criteria were transitional anatomy, severe hip osteoarthritis, coronal deformity with cobb >10 degrees, > grade 1 spondylolisthesis at L4-L5 and anterior migration of the psoas.Standing and supine lumbar lordosis (LL) and its proximal (L1-L4) and distal (L4-S1) components were measured. Femoral nerve position on sagittal imaging was then measured as a percentage of the L4 inferior endplate. A stepwise multivariate linear regression of sagittal alignment and LL parameters was then performed. Data are written as estimate, 95% CI., Results: Mean patient age was 58.2±14.7 years, 25 (34.2%) were female and 26 (35.6%) had a grade 1 spondylolisthesis. Mean femoral nerve position was 26.6±10.3% from the posterior border of L4. Female sex (-6.6, -11.1 to -2.1) and supine proximal lumbar lordosis (0.4, 0.1-0.7) were independently associated with femoral nerve position., Conclusions: Patient sex and proximal LL can serve as early indicators of the size of the femoral nerve safe zone during a transpsoas LLIF approach at L4-L5., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective National Database Study., Objectives: The aim of this study was to investigate the national trend of lumbar disc arthroplasty (LDA) utilization from 2005 to 2017., Methods: Patients undergoing primary LDA between 2005 and 2017 were identified in the National Inpatient Sample (NIS) database. Year of the procedure, demographic, socioeconomic, hospital, and cost parameters were analyzed. The data was weighted using provided weights from the NIS database to generate national estimates of LDA procedure incidence. Lastly, we assessed the incidence of cervical disc arthroplasty (CDA) between 2005 and 2017 to serve as a historical comparison., Results: An estimated 20 460 patients underwent primary LDA in the United States between 2005 and 2017. There was an initial decrease in LDA procedures between 2005 and 2006 and then a plateau between 2006 and 2009. From 2010 to 2013, there was a significant year-over-year decrease in annual LDA procedures performed, followed by a second plateau from 2014 to 2017. Overall, LDA procedures decreased 82% from 2005 to 2017. Over the same time, the annual incidence of CDA utilization increased 795% from approximately 474 procedures in 2005 to 4245 procedures in 2017 ( P < .01)., Conclusions: Lumbar disc arthroplasty utilization decreased 82% from 2005 to 2017, with a significant decrease in the rate of utilization noted after 2010. The utilization of LDA to treat selected degenerative lumbar conditions has not paralleled the increasing popularity of CDA, and, in fact, has demonstrated a nearly opposite utilization trend.

Study Design: Narrative review., Objectives: The purpose of this review is to outline the role of sex hormones, particularly estrogen, in the pathogenesis of degenerative disc disease (DDD)., Methods: A narrative review of studies discussing sex hormones and intervertebral disc (IVD) degeneration was conducted through a search of bibliographic databases to identify various mechanisms involved in effectuating DDD., Results: Estrogen-deficient states negatively impact various aspects of IVD function. These internal hormone environments reflect routine changes that commonly arise with physiologic aging and can compromise IVD structural integrity through a host of processes. Additionally, allosteric molecules such as micro-RNAs (mi-RNAs) and G protein-coupled estrogen receptors (GPER) antagonists can bind to estrogen receptors and inhibit protective downstream effects with estrogen receptor signaling. Furthermore, cursory studies have observed chondrogenic effects with testosterone supplementation, although the specific mechanism remains unclear., Conclusions: Regulation of sex hormones, namely estrogen and testosterone, significantly impacts the structural integrity and function of IVDs. Uncovering underlying interactions driving these regulatory processes can facilitate development of novel, clinical therapies to treat DDD.

Background: Antibodies to β2-glycoprotein I (β2GPI) cause thrombosis in antiphospholipid syndrome, however the role of β2GPI itself in regulation of coagulation pathways in vivo is not well understood., Methods: We developed β2GPI-deficient mice (Apoh -/- ) by deleting exon 2 and 3 of Apoh using CRISPR/Cas9 and compared the propensity of wild-type (WT) and Apoh -/- mice to develop thrombosis using rose bengal and FeCl 3 -induced carotid thrombosis, laser-induced cremaster arteriolar injury, and inferior vena cava (IVC) stasis models. We also compared tail bleeding times and assessed platelet activation in WT and Apoh -/- mice in the absence and presence of exogenous β2GPI., Results: Compared to WT littermates, Apoh -/- mice demonstrated a prolonged time to occlusion of the carotid artery after exposure to rose bengal or FeCl 3 , and reduced platelet and fibrin accumulation in cremasteric arterioles after laser injury. Similarly, significantly smaller thrombi were retrieved from the IVC of Apoh -/- mice 48 hours after IVC occlusion. The activated partial thromboplastin time (aPTT) and prothrombin time, as well as aPTT reagent- and tissue factor-induced thrombin generation times using plasma from Apoh -/- and WT mice revealed no differences. However, we observed significant prolongation of tail bleeding in Apoh -/- mice, and reduced P-selectin expression and binding of fibrinogen to the activated α2bβ3 integrin on platelets from these mice after stimulation with low thrombin concentrations; these changes were reversed by exogenous β2GPI. An antibody to PAR3 blocked thrombin-induced activation of WT, but not Apoh -/- platelets, as well as the ability of β2GPI to restore the activation response of Apoh -/- platelets to thrombin. β2GPI deficiency did not affect platelet activation by a PAR4-activator peptide, or ADP., Conclusions: In mice, β2GPI may mediate procoagulant activity by enhancing the ability of PAR3 to present thrombin to PAR4, promoting platelet activation at low thrombin concentrations., Key Points: β2GPI deficient mice are protected from experimental arterial, venous, and microvascular thrombosis.β2GPI deficient mice display prolonged tail bleeding times and reduced PAR3-facilitated platelet activation by low concentrations of thrombin.

Study Design/setting: Retrospective cohort analysis., Objectives: This study evaluates utilization and demographic trends for sacroiliac joint (SIJ) fusions across the United States (US)., Methods: Patients who underwent SIJ fusion from 2010-2021 were identified within the PearlDiver national database using International Classification of Disease (ICD-9, ICD-10) and Current Procedural Terminology (CPT) codes. Indications for trauma, malignancy, or infection were excluded. Demographic, clinical, and procedure characteristics were recorded along with annual utilization rates. Annual percent change (APC) was calculated to identify increasing or decreasing utilization from prior years. Negative binomial regression was performed to project subsequent utilization for 2022-2028. Chi-squared analysis followed by post-hoc comparisons were used to compare differences in diagnostic indications and clinical features associated with SIJ fusion across regions. Bonferroni adjustments were applied to P -values for pairwise analyses., Results: Overall, 18 032 patients (69.8% female, mean age = 51.0 + 13.4 years) underwent SIJ fusion between 2010 and 2021. Annual utilization increased by 33.5% on average. The South comprised the largest proportion of cases (48.9%). Projections for 2022-2028 predict continued growth in procedures, with an overall increase of 1100% from 1350 cases in 2021 to 16 195 by end of 2028. Spondyloarthropathy-induced sacroilitis was the most prevalent diagnostic indication nationwide (51%). Of patients undergoing SIJ fusion, 18% had a prior lumbar fusion, and only 45% received a preoperative diagnostic SIJ injection., Conclusion: As SIJ fusion is increasingly utilized to treat refractory SIJ-based pain, establishing evidence-based guidelines, improving diagnostic strategies, and defining indications are imperative to support growing applications within clinical practice., 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.

Objective: Studies have reported the detrimental effects of depression following spine surgery; however, none have evaluated whether preoperative depression screening in patients with a history of depression is protective from adverse outcomes and lowers health care costs. We studied whether depression screenings/psychotherapy visits within 3 months before 1- to 2-level lumbar fusion were associated with lower medical complications, emergency department utilization, readmissions, and health care costs., Methods: The PearlDiver database from 2010 to 2020 was queried for depressive disorder (DD) patients undergoing primary 1- to 2-level lumbar fusion. Two cohorts were 1:5 ratio matched and included DD patients with (n = 2,622) and DD patients without (n = 13,058) a preoperative depression screen/psychotherapy visit within 3 months of lumbar fusion. A 90-day surveillance period was used to compare outcomes. Logistic regression models computed odds ratio (OR) of complications and readmissions. P value < 0.003 was significant., Results: DD patients without depression screening had significantly greater incidence and odds of experiencing medical complications (40.57% vs. 16.00%; OR 2.71, P < 0.0001). Rates of emergency department utilization were increased in patients without screening versus screening (15.78% vs. 4.23%; OR 4.25, P < 0.0001), despite no difference in readmissions (9.31% vs. 9.53%; OR 0.97, P = 0.721). Finally, 90-day reimbursements ($51,160 vs. $54,731) were significantly lower in the screened cohort (all P < 0.0001)., Conclusions: Patients who underwent a preoperative depression screening within 3 months of lumbar fusion had decreased medical complications, emergency department utilization, and health care costs. Spine surgeons may use these data to counsel their patients with depression before surgical intervention., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Purpose: Current decision-making in multilevel cervical fusion weighs the potential to protect adjacent levels and reduce reoperation risk by crossing the cervicothoracic junction (C7/T1) against increased operative time and risk of complication. Careful planning is required, and the planned distal and adjacent levels should be assessed for degenerative disc disease (DDD). This study assessed whether DDD at the cervicothoracic junction was associated with DDD, disc height, translational motion, or angular variation in the adjacent superior (C6/C7) or inferior (T1/T2) levels., Methods: This study retrospectively analyzed 93 cases with kinematic MRI. Cases were randomly selected from a database with inclusion criteria being no prior spine surgery and images having sufficient quality for analysis. DDD was assessed using Pfirrmann classification. Vertebral body bone marrow lesions were assessed using Modic changes. Disc height was measured at the mid-disc in neutral and extension. Translational motion and angular variation were calculated by assessing translational or angular motion segment integrity respectively in flexion and extension. Statistical associations were assessed with scatterplots and Kendall's tau., Results: DDD at C7/T1 was positively associated with DDD at C6/C7 (tau = 0.53, p < 0.01) and T1/T2 (tau = 0.58, p < 0.01), with greater disc height in neutral position at T1/T2 (tau = 0.22, p < 0.01), and with greater disc height in extended position at C7/T1 (tau = 0.17, p = 0.04) and at T1/T2 (tau = 0.21, p < 0.01). DDD at C7/T1 was negatively associated with angular variation at C6/C7 (tau = - 0.23, p < 0.01). No association was appreciated between DDD at C7/T1 and translational motion., Conclusion: The association of DDD at the cervicothoracic junction with DDD at the adjacent levels emphasizes the necessity for careful selection of the distal level in multilevel fusion in the distal cervical spine., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Study Design: Retrospective cross-sectional review of a large database., Objective: Little is known regarding extension K-lines for treatment of cervical myelopathy. Therefore, this study seeks to examine differences between K-lines drawn in neutral and extension., Summary of Background Data: The modified K-line is a radiological tool used in surgical planning of the cervical spine. As posterior cervical decompression and fusion often results in patients being fused in a more lordotic position than the preoperative neutral radiograph, a K-line measured in the extension position may offer better utility for these patients., Materials and Methods: Total of 97 patients were selected with T2-weighted, upright cervical magnetic resonance imaging taken in neutral and extension. For each patient, the K-line was drawn at the mid-sagittal position for both neutral and extension. The distance from the most posterior portion of each disk (between C2 and C7) to the K-line was measured in neutral and extension and the difference was calculated. Paired t test was used to assess significant differences., Results: Across all levels between C2 and C7 there was an increase in the distance between the dorsal aspect of the disk and K-line when comparing neutral and extension radiographs. The average change in difference (extension minus neutral) at each cervical spinal level was 0.9 mm (C2-C3), 2.5 mm (C3-C4), 2.6 mm (C4-C5), 2.0 mm (C5-C6), and 0.9 mm (C6-C7). A paired t test showed that the K-line increase from neutral to extension was statistically significant across all disk levels ( P <0.001)., Conclusion: When positioned in extension, patients experience a significant increase in distance from the dorsal aspect of a disk to the K-line compared to when positioned in neutral, especially between C3 and C6. This is clinically relevant for surgeons considering a posterior cervical decompression and fusion in patients with a negative modified K-line on preoperative magnetic resonance imaging, as these patients may have enough cervical cord drift back when fused in an extended position, maximizing likelihood of improving postoperative DSM functional outcomes., Competing Interests: Z.B.—consultancy: Cerapedics (past), Research Support: SeaSpine (past, paid to the institution), Next Science (paid directly to institution), Medical Metrics (past, paid directly to institution), NIH SBIR Subaward (paid to institution); North American Spine Society: committee member; Lumbar Spine Society: Co-chair Educational Committee, AOSpine Knowledge Forum Degenerative: Associate member; AOSNA Research committee—committee member: patents (issued): Biomarkers for painful intervertebral discs and methods of use thereof. R.J.H.: consultant and royalties NuVasive, research support (paid to institution): si-bone and a-tec, committees: NASS, LSRS, editorial board: GSC. J.C.W.: Royalties—Biomet, Seaspine, Synthes, Investments/Options—Bone Biologics, Pearldiver, Electrocore, consulting: precision OS, Board of Directors—AO Foundation, National Spine Health Foundation, Editorial Boards—Global Spine Journal Editor-in-Chief, Fellowship Funding (paid to institution): AO Foundation. R.K.A.: stock options from HIA, Senior Reviewer for IJSS. The remaining authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: The objective of this study is to assess differences in complication profiles between 3-level posterior column osteotomy (PCO) and single-level pedicle subtraction osteotomy (PSO) as both are reported to provide similar degrees of sagittal correction., Methods: The PearlDiver database was queried retrospectively using International Classification of Disease, 9th and 10th edition and Current Procedural Terminology codes to identify patients who underwent PCO or PSO for degenerative spine disease. Patients under age 18 or with history of spinal malignancy, infection, or trauma were excluded. Patients were separated into 2 cohorts, 3-level PCO or single-level PSO, matched at a 1:1 ratio based on age, sex, Elixhauser comorbidity index, and number of fused posterior segments. Thirtyday systemic and procedure-related complications were compared., Results: Matching resulted in 631 patients for each cohort. PCO patients had decreased odds of respiratory (odds ratio [OR], 0.58; 95% confidence interval [CI], 0.43-0.82; p = 0.001) and renal complications (OR, 0.59; 95% CI, 0.40-0.88; p = 0.009) compared to PSO patients. There was no significant difference in cardiac complications, sepsis, pressure ulcer, dural tear, delirium, neurologic injuries, postoperative hematoma, postoperative anemia, or overall complications., Conclusion: Patients who undergo 3-level PCO have decreased respiratory and renal complications compared to single-level PSO. No differences were found in the other complications studied. Considering both procedures achieve similar sagittal correction, surgeons should be aware that 3-level PCO offers an improved safety profile compared to single-level PSO.

Background: The purpose of this review is to provide a brief history of previous attempts at developing patient screening tools and to further examine the definitions of these psychological concepts, relevance to clinical outcomes, and implications for spine surgeons during preoperative patient assessments., Methods: A literature review was performed by 2 independent researchers to identify original manuscripts related to spine surgery and novel psychological concepts. The history of presurgical psychology screening was also studied, and definitions of frequently utilized metrics were detailed., Results: Seven manuscripts were identified that utilized psychological metrics for preoperative risk assessments and correlated outcomes with these scores. The metrics most frequently used in the literature included resilience, patient activation, grit, and self-efficacy., Discussion: Current literature favors resilience and patient activation as important metrics for preoperative patient screening. Available studies demonstrate significant associations between these character traits and patient outcomes. Further research is warranted to investigate the roles of preoperative psychological screening to optimize patient selection in spine surgery., Clinical Relevance: The purpose of this review is to provide clinicians with a reference for available psychosocial screening tools and their relevance to patient selection. This review also serves to guide future research directions given the importance of this topic., Competing Interests: Declaration of Conflicting Interests : Jeffrey Wang reports payment for expert testimony from law firms; a leadership role and expense reimbursement from the AO Foundation Board; stock/stock options from Bone Biologics, Pearldiver, and Electrocore; and fellowship funding from AO Spine North America (paid to institution). The remaining authors have nothing to disclose., (This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2023 ISASS. To see more or order reprints or permissions, see http://ijssurgery.com.)

Background: Cervical disc arthroplasty (CDA) was originally approved by the US Food and Drug Administration (FDA) in 2007 as a motion-sparing procedure to treat cervical degenerative disc disease. Since then, promising results from randomized control trials have led to increasing popularity. However, data discussing monetary trends are limited. The aim of this study was to determine how utilization, hospital charges, and Medicare physician reimbursement for CDA have changed over time., Methods: In this retrospective cohort study, International Classification of Diseases procedure codes were used to identify all patients who underwent CDA from 2007 to 2017 in the National Inpatient Sample database. The Physician Fee Schedule Look-up Tool from the Centers for Medicare and Medicaid Services was queried for primary CDA using current procedural terminology codes to determine Medicare physician reimbursement from 2009 to 2021. Nominal monetary values were adjusted for inflation using the Consumer Price Index and inflation-adjusted data reported in 2021 US dollars., Results: A total of 33,079 weighted patients who underwent CDA were included for analysis. CDA utilization increased by 183% from 2007 to 2017, with Medicare beneficiary utilization increasing 149%. Inflation-adjusted total hospital charges for CDA increased by 22.4%. However, inflation-adjusted Medicare physician reimbursement fell by 1.20% per year, demonstrating a total decrease of 12.9%, starting at $1928 in 2009 and declining to $1679 in 2021., Conclusions: While utilization and total hospital charges for CDA continue to rise, Medicare physician reimbursement has not shown the same trend. In fact, inflation-adjusted reimbursement has seen a steady decline since FDA approval in 2007. If this trend persists, it may become unsustainable for physicians to continue offering CDA to Medicare patients. As disproportionate increases in hospital charges incentivize a transition to outpatient CDA, stricter patient selection criteria associated with outpatient procedures may create health care disparities for Medicare patients and those with higher comorbidity burden., Clinical Relevance: This study shows the decreasing reimbursement trends for CDA, which may disproportionately affect Medicare patients and those with increased comorbidities., Competing Interests: Declaration of Conflicting Interests : There are no direct conflicts of interest in this study. Emily S. Mills, Cory K. Mayfield, Tara Shelby, and Andy T. Ton have no conflicts to declare. Raymond J. Hah is a paid consultant for Nuvasive. He is on the editorial boards for Global Spine Journal, Clinical Spine Surgery, and The Spine Journal. Ram K. Alluri is a paid consultant and receives royalties from HIA Technologies Incorporated., (This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2023 ISASS. To see more or order reprints or permissions, see http://ijssurgery.com.)

Background: Arthroplasty surgeons use the change in sacral slope (ΔSS) from sitting to standing as a measure of spinal motion. The relationship between ΔSS and the change in lumbar lordosis (ΔLL), an established spinal motion measure, has not been well studied. This study aims to determine the correlation between ΔSS and ΔLL., Methods: Consecutive patients presenting to a spine clinic from 2020 to 2021 at a single institution were retrospectively studied. Standing and sitting lateral radiographs were measured for SS and LL. Patients were divided using ΔSS and ΔLL into stiff (0°-9°), normal (10°-30°), or hypermobile (>30°) category. Patients with a ΔSS-determined normal or hypermobile spine but a ΔLL-determined stiff spine were compared to the rest of the cohort., Results: Overall, 100 patients were included. Of these patients, 47% had the same classification when looking at ΔSS and ΔLL, whereas 53% had conflicting classifications. Twenty percent of patients had a ΔSS-determined normal or hypermobile spine but ΔLL-determined stiff spine. The correlation between ΔSS and ΔLL was 0.510 ( P < .001). When isolating patients who underwent lumbar fusion, the correlation between ΔSS and ΔLL was 0.345 ( P < .001)., Conclusions: ΔSS has a moderate correlation with ΔLL in patients presenting for evaluation of their lumbar spine but low correlation in patients with lumbar fusion. In our cohort, 20% of patients had a ΔSS-determined normal or hypermobile spine but a ΔLL-determined stiff spine, representing a potential high-risk dislocation cohort not captured by ΔSS alone. Arthroplasty surgeons should revisit classifying spinal motion based solely on ΔSS., (© 2023 The Authors.)

Study Design: Retrospective review of private neuromonitoring databases., Objectives: To review neuromonitoring alerts in a large series of patients undergoing lateral lumbar interbody fusion (LLIF) and determine whether alerts occurred more frequently when more lumbar levels were accessed or more frequently at particular lumbar levels., Methods: Intraoperative neuromonitoring (IONM) databases were reviewed and patients were identified undergoing LLIF between L1 and L5. All cases in which at least one IONM modality was used (motor evoked potentials (MEP), somatosensory evoked potentials (SSEP), evoked electromyography (EMG)) were included in this study. The type of IONM used and incidence of alerts were collected from each IONM report and analyzed. The incidence of alerts for each IONM modality based on number of levels at which at LLIF was performed and the specific level an LLIF was performed were compared., Results: A total of 628 patients undergoing LLIF across 934 levels were reviewed. EMG was used in 611 (97%) cases, SSEP in 561 (89%), MEP in 144 (23%). The frequency of IONM alerts for EMG, SSEP and MEPs did not significantly increase as the number of LLIF levels accessed increased. No EMG, SSEP, or MEP alerts occurred at L1-L2. EMG alerts occurred in 2-5% of patients at L2-L3, L3-L4, and L4-L5 and did not significantly vary by level ( P = .34). SSEP and MEP alerts occurred more frequently at L4-L5 versus L2-L3 and L3-L4 ( P < .03)., Conclusions: IONM may provide the greatest utility at L4-L5, particularly MEPs, and may not be necessary for more cephalad LLIF procedures such as at L1-L2.

Background: Intraoperative neuromonitoring (IONM) is frequently used during spine surgery to mitigate the risk of neurological injuries. Yet, its role in anterior cervical spine surgery remains controversial. Without consensus on which anterior cervical spine surgeries would benefit the most from IONM, there is a lack of standardized guidelines for its use in such procedures. Purpose : We sought to assess the alerts generated by each IONM modality for 4 commonly performed anterior cervical spinal surgeries: anterior cervical diskectomy and fusion (ACDF), anterior cervical corpectomy and fusion (ACCF), cervical disk replacement (CDR), or anterior diskectomy. In doing so, we sought to determine which IONM modalities (electromyography [EMG], motor evoked potentials [MEP], and somatosensory evoked potentials [SSEP]) are associated with alert status when accounting for procedure characteristics (number of levels, operative level). Methods : We conducted a retrospective review of IONM data collected by Accurate Neuromonitoring, LLC, a company that supports spine surgeries conducted by 400 surgeons in 8 states, in an internally managed database from December 2009 to September 2018. The database was queried for patients who underwent ACCF, ACDF, anterior CDR, or anterior diskectomy in which at least 1 IONM modality was used. The IONM modalities and incidence of alerts were collected for each procedure. The search identified 8854 patients (average age, 50.6 years) who underwent ACCF (n = 209), ACDF (n = 8006), CDR (n = 423), and anterior diskectomy (n = 216) with at least 1 IONM modality. Results : Electromyography was used in 81.3% (n = 7203) of cases, MEP in 64.8% (n = 5735) of cases, and SSEP in 99.9% (n = 8844) of cases. Alerts were seen in 9.3% (n = 671), 0.5% (n = 30), and 2.7% (n = 241) of cases using EMG, MEP and SSEP, respectively. In ACDF, a significant difference was seen in EMG alerts based on the number of spinal levels involved, with 1-level ACDF (6.9%, n = 202) having a lower rate of alerts than 2-level (10.0%, n = 272), 3-level (15.2%, n = 104), and 4-level (23.4%, n = 15). Likewise, 2-level ACDF had a lower rate of alerts than 3-level and 4-level ACDF. A significant difference by operative level was noted in EMG use for single-level ACDF, with C2-C3 having a lower rate of use than other levels. Conclusions : This retrospective review of anterior cervical spinal surgeries performed with at least 1 IONM modality found that SSEP had the highest rate of use across procedure types, whereas MEP had the highest rate of nonuse. Future studies should focus on determining the most useful IONM modalities by procedure type and further explore the benefit of multimodal IONM in spine surgery., Competing Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Sheeraz A. Qureshi, MD, MBA, reports relationships with AMOpportunities, Globus Medical, Healthgrades, K2M, Lifelink.com, Minimally Invasive Spine Specialty Group, Paradigm Spine, RTI Surgical, Stryker, Spinal Simplicity, Tissue Differentiation Intelligence, Vital 5. The other authors declare no potential conflicts of interest., (© The Author(s) 2022.)

Background: Painful vertebral osteoporotic compression fractures (OCFs) are often treated with cement augmentation, although controversies exist as to whether or not this increases the secondary fracture risk. Prevention of secondary fracture includes treatment of underlying osteoporosis. The purposes of this study were to determine (1) whether cement augmentation increases the rate of secondary fracture compared with nonoperative management, (2) whether anti-osteoporotic medications reduce the rate of secondary fracture, and (3) the rate of osteoporosis treatment with medications following vertebral OCF., Methods: The PearlDiver database was queried for all patients with a diagnosis of OCF from 2015 to 2019. Patients were excluded if they were <50 years old, had a diagnosis of spinal neoplasm or infection, or underwent lumbar fusion in the perioperative period. Secondary fracture risk was assessed using univariate and multivariate logistic regression analysis, with kyphoplasty, vertebroplasty, anti-osteoporotic medications, age, gender, and Elixhauser Comorbidity Index as variables., Results: A total of 36,145 patients were diagnosed with an OCF during the study period. Of those, 25,904 (71.7%) underwent nonoperative management and 10,241 (28.3%) underwent cement augmentation, including 1,556 who underwent vertebroplasty and 8,833 who underwent kyphoplasty. Patients who underwent nonoperative management had a secondary fracture rate of 21.8% following the initial OCF, compared with 14.5% in the vertebroplasty cohort and 18.5% in the kyphoplasty cohort, which was not a significant difference on multivariate analysis. In the entire cohort, 2,833 (7.8%) received anti-osteoporotic medications and 33,312 (92.2%) did not. The rate of secondary fracture was 10.1% in patients who received medications and 21.9% in those who did not, which was a significant difference on multivariate analysis (odds ratio = 1.23, p < 0.001)., Conclusions: Cement augmentation did not alter the rate of secondary fracture, whereas anti-osteoporotic medications significantly decreased the risk of subsequent OCF by 19%. Only 7.8% of patients received a prescription for an anti-osteoporotic medication following the initial OCF., Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H267 )., (Copyright © 2022 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: Management of scaphoid nonunions with bone loss varies substantially. Commonly, internal fixation consists of a single headless compression screw. Recently, some authors have reported on the theoretical benefits of dual-screw fixation. We hypothesized that using 2 headless compression screws would impart improved stiffness over a single-screw construct., Methods: Using a cadaveric model, we compared biomechanical characteristics of a single tapered 3.5- to 3.6-mm headless compression screw with 2 tapered 2.5- to 2.8-mm headless compression screws in a scaphoid waist nonunion model. The primary outcome measurement was construct stiffness. Secondary outcome measurements included load at 1 and 2 mm of displacement, load to failure for each specimen, and qualitative assessment of mode of failure., Results: Stiffness during load to failure was not significantly different between single- and double-screw configurations ( P = .8). Load to failure demonstrated no statistically significant difference between single- and double-screw configurations. Using a qualitative assessment, the double-screw construct maintained rotational stability more than the single-screw construct ( P = .029)., Conclusions: Single- and double-screw fixation constructs in a cadaveric scaphoid nonunion model demonstrate similar construct stiffness, load to failure, and load to 1- and 2-mm displacement. Modes of failure may differ between constructs and represent an area for further study. The theoretical benefit of dual-screw fixation should be weighed against the morphologic limitations to placing 2 screws in a scaphoid nonunion.

Study Design: Retrospective national database study design., Purpose: This study was designed to determine whether acute percutaneous vertebral augmentation (PVA) alters morbidity compared with nonoperative management., Overview of Literature: Osteoporotic vertebral compression fractures (OCFs) are common and represent a large economic and patient burden. Several recent studies have focused on whether PVA offers benefits compared with nonoperative treatment., Methods: A retrospective cohort analysis was conducted using the Nationwide Inpatient Sample from 2015 to 2018. Patients with nonelective admissions for OCFs were identified using International Classification of Diseases (10th edition) codes. The exclusion criteria included age of less than 50 years, fusion and decompression procedures, and the presence of neoplasms and infections. Propensity score matching was implemented to construct 2:1 matched cohorts with similar comorbidities at admission. The patients were divided into the operative and nonoperative treatment groups. Univariate and multivariate regression analyses were performed to compare differences in in-hospital complication rates between the groups. All p-values of less than 0.05 were considered significant., Results: We identified 14,850 patients in the operative group and 29,700 patients in the nonoperative group. In the multivariate analysis, operative treatment was associated with significantly lower rates of pneumonia (odds ratio [OR], 0.75; p<0.001), acute respiratory failure (OR, 0.84; p=0.009), myocardial infarction (OR, 0.20; p<0.001), acute heart failure (OR, 0.80; p=0.001), cardiogenic shock (OR, 0.23; p=0.001), sepsis (OR, 0.39; p<0.001), septic shock (OR 0.50; p<0.001), and pressure ulcerations (OR, 0.71; p<0.001). However, operative treatment was associated with a significantly greater risk of acute renal failure (OR, 1.19; p<0.001) than nonoperative treatment., Conclusions: Patients who undergo acute PVA for OCFs have lower rates of respiratory complications, cardiac complications, sepsis, and pressure ulcerations while having a higher risk of acute renal failure.

Study Design: Retrospective study of a multicenter Adult Spinal Deformity (ASD) Database., Objective: To investigate the change in Pelvic tilt (PT) imparted by regional changes in lumbar lordosis at 2-year minimum follow up., Summary of Background Data: The distribution of lumbar lordosis between L1-4 and L4-S1 is known to vary based on pelvic incidence (PI). However, the extent to which regional changes effect PT is not clearly elucidated. This information can be useful for ASD surgical planning., Methods: Operative patients from a multicenter ASD database were included with Lowest Instrumented Vertebrae (LIV) S1/Ilium, >5 levels of fusion, Proximal Junction Kyphosis (PJK) angle < 20, and >5 degrees of change in lumbar lordosis from L4-S1 and L1-4. Radiographic analysis was performed evaluating Thoracic Kyphosis (TK), T10-L2 kyphosis (TL), L1-S1 lordosis (LL), L4-S1 lordosis, L1-4 lordosis, sagittal vertical axis (SVA) and PI-LL from preoperative to postoperative, and change at 2-years follow-up. Stepwise regression analysis was performed in order to determine the relationship between PT and the above radiographic parameters. Health-related quality of life (HRQOL) outcomes were also compared between preoperative and postoperative timepoints at 2 years., Results: 103 patients met inclusion for the study. There was improvement in all the radiographic parameters and HRQOLs at 2 years follow-up (p < 0.01). Stepwise regression model showed an inverse relationship between PT and LL change (r = 0.71, p < 0.01). Regionally, an increase in 10 degrees from L4-S1 correlated with a 2.4 degree decrease in PT (p < 0.01), while an increase in 10 degrees from L1-4 resulted in a 1.6 degree decrease in PT (p < 0.01)., Conclusion: In the surgical planning for ASD, our data demonstrated significant correlational difference between corrections in the upper (L1-4) and lower (L4-S1) lumbar spine and PT changes. These calculations can be useful in planning sagittal plane corrections for ASD., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective cohort study., Objectives: The aim of this study was to examine sagittal alignment over time in adult spinal deformity (ASD) and to understand whether these changes vary by choice of upper instrumented vertebra (UIV)., Summary of Background Data: Recent ASD literature has focused on specific alignment goals. Less is known about how sagittal parameters evolve over time after surgical correction and whether these changes differ by choice of UIV., Methods: This was a retrospective review of ASD patients from a single institution. Routine 36″ sagittal x-rays were obtained preoperatively, before hospital discharge, and at 6 months, 1 year, and 2 years and sagittal parameters were measured. Patients with UIV T6 and above were classified as upper thoracic (UT) and T7 and below as lower thoracic (LT)., Results: A total of 102 patients with mean age 66.0 years (±7.7) were included in the analysis (49 UT, 53 LT). All sagittal and coronal alignment parameters demonstrated significant improvement from preoperatively to any postoperative time point. Although multiple parameters maintained correction over time, others (TK, TPA, and PT) demonstrated significant increase from discharge to 2 years postoperatively, with changes occurring relatively early after surgery, whereas overall global alignment was maintained. Both UT/LT groups demonstrated significantly greater TK from preoperatively to discharge to 6 months (P  < 0.05), stabilizing at that time point out to 2 years, whereas TLK preferentially increased in the LT group. There was significant improvement in sagittal vertical axis after surgery, which was maintained out to 2years of follow-up (P > 0.05)., Conclusions: Our data suggest that although several key parameters are maintained over time out to 2years postopera- tively, TK tends to worsen over time for all patients, whereas TLK preferentially increases in the LT group. Nevertheless, despite these trends, compensatory changes are seen in PT such that global alignment is relatively maintained.Level of Evidence: 3., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective review., Objective: To analyze if shoulder balance continues to change in the postoperative period in patients undergoing selective lumbar fusion for adult spinal deformity (ASD), and secondarily, analyze if shoulder balance correlates with health-related quality of life (HRQOL) outcomes., Summary of Background Data: Shoulder balance in patients with ASD is poorly understood and has largely been extrapolated from adolescent scoliosis literature., Materials and Methods: Adult patients who underwent selective lumbar fusion (upper instrumented vertebra: Τ9-Τ12, lower instrumented vertebra: L4-Pelvis) for thoracolumbar or lumbar scoliosis (cobb angle > 30°) or sagittal plane deformity with thoracic compensatory curves (cobb angle > 10°) were identified. The clavicular angle (CA) was used to quantify shoulder balance. Shoulder balance was categorized into three groups postoperatively (balanced: CA <2°, mild imbalance: CA 2°-4°, severe imbalance: CA >4°). The average CA and proportion of patients in each shoulder balance group were compared at each postoperative period. Patients with 1-year postoperative HRQOL scores were identified., Results: Eighty-six patients were included. The preoperative CA was 2.7 ± 2.3° and did not significantly change at discharge (2.9 ± 2.4°), 6-weeks (2.5 ± 2.1°), 6-months (2.4 ± 2.2°), 1-year (2.4 ± 2.5°), or 2-years (2.3 ± 1.5°) postoperatively. The proportion of patients in each shoulder balance group did not significantly change from discharge to 6-weeks, 6-months, 1-year or 2-years postoperatively (P > 0.1). At 1-year follow-up, the CA demonstrated no significant correlation with Oswestry Disability Index, Scoliosis Research Society (SRS)-22 score, or SRS-22 subscores. There was no significant association between shoulder balance group and Oswestry Disability Index, SRS-22 score, or SRS-22 subscores., Conclusions: In patients with ASD undergoing selective lumbar fusion, shoulder balance did not change over the postoperative period. From a functional standpoint, shoulder balance demonstrated no correlation with HRQOL scores. In patients undergoing selective lumbar fusion for ASD, shoulder balance may not spontaneously correct over the postoperative period, but this may not be of functional consequence.Level of Evidence: 4., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective cohort study., Objectives: The aim was to compare the minimally clinically important difference (MCID) across multiple patient-reported outcomes (PROs) in patients undergoing cervical disc replacement (CDR) for cervical spondylotic radiculopathy versus myeloradiculopathy., Summary of Background Data: To date, a limited number of studies have demonstrated mostly similar results in patients with cervical spondylotic radiculopathy or myeloradiculopathy undergoing CDR. However, each of these previous studies have focused on statistically significant differences, which may not correlate with patient perceived improvements in outcomes or success., Methods: Patients who underwent 1 or 2-level CDR with radiculopathy versus myeloradiculopathy were identified, and prospectively collected data was retrospectively reviewed. Demographic variables, preoperative diagnosis, and operative variables were collected for each patient. The following PROs were prospectively collected: Neck Disability Index (NDI), visual analog scale (VAS)-Neck, VAS-Arm, Short Form-12 Health Survey (SF-12) Physical Component Score (PCS), SF-12 Mental Component Score (MCS), PROMIS Physical Function (PF). An MCID analysis of PROs for each diagnosis group was performed and the percentage of patients achieving the MCID was compared between the two diagnosis groups., Results: Eight-five patients, of which 56% had radiculopathy and 44% had myeloradiculopathy. MCID analysis demonstrated that at 6-week, 12-week, and final postoperative follow-up there was no significant difference in the percentage of patients with radiculopathy or myeloradiculopathy achieving the MCID for each PRO assessed. In both diagnosis groups the percentage of patients achieving the MCID for each PRO continued to increase from the 6-week to final postoperative follow-up except for the SF-12 MCS in patients with myeloradiculopathy., Conclusions: The percentage of patients achieving the MCID was not significantly different at each postoperative period assessed in the radiculopathy and myeloradiculopathy groups treated with CDR. In addition, the percentage of patients achieving the MCID continued to increase from 6 weeks to final follow-up in both groups for almost all PROs assessed., Competing Interests: The authors declare no conflict of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Background Context: Patients undergoing minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) frequently present with lower extremity neurologic symptoms with or without associated lower back pain. While symptomatic improvement of leg and back pain has been reported, the resolution of back pain when it is a predominant presenting symptom remains underreported following MI-TLIF., Purpose: The purpose of this study was to compare clinical outcomes at 1 year of patients undergoing MI-TLIF with lower extremity neurologic symptoms with and without a significant component of back pain., Study Design: A retrospective review of prospectively collected data from a single surgeon surgical database from 2017 to 2019 was performed., Patient Sample: Fifty one patients undergoing MI-TLIF., Outcome Measures: Self-reported measures included the Oswestry Disability Index (ODI), Visual analog scale back pain (VAS-back), and VAS leg pain (VAS-leg)., Methods: Patients were divided into two groups: Leg Pain Predominant (patients reported greater than 50% leg pain upon presentation) and Back Pain Predominant (patients reported 50% or greater back pain). Multivariate analysis was performed to determine differences between groups based upon any significantly baseline characteristics., Results: Preoperative demographic and radiographic outcomes were similar between the two groups. Both groups demonstrated significant improvement in ODI, VAS-Back and VAS-leg at 1-year postoperatively. On multivariate analysis, there were differences in ODI at 1-year, 1-year back pain, and 1-year leg pain between groups with those who initially presented with leg pain having a lower ODI, VAS Back, and VAS leg. Patients who presented with predominantly leg pain were more likely to meet minimal clinically important difference (MCID) criteria for ODI and VAS-back compared to those with predominantly back pain., Conclusion: Following MI-TLIF, patients with lower extremity neurologic symptoms with and without a significant component of back pain have improvements in back pain, leg pain, and ODI regardless of their primary presenting pain complaint; however, patients who presented with predominantly leg pain were more likely to meet MCID criteria for improvement in their back pain and ODI score., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Study Design: Literature review., Objectives: To review the evidence for surface-based navigation in minimally-invasive spine surgery (MIS), provide an outline for its workflow, and present a wide range of MIS case examples in which surface-based navigation may be advantageous., Methods: A comprehensive review of the literature and compilation of findings related to surface-based navigation in MIS was performed. Workflow and case examples utilizing surface-based navigation were described., Results: The nascent literature regarding surface-based intraoperative navigation (ION) in spine surgery is encouraging and initial studies have shown that surface-based navigation can allow for accurate pedicle screw placement and decreased operative time, fluoroscopy time, and radiation exposure when compared to traditional fluoroscopic imaging. Surface-based navigation may be particularly useful in MIS cervical and lumbar decompressions and MIS lumbar instrumentation cases., Conclusions: Overall, it is possible that surface-based ION will become a mainstay in the armamentarium of enabling technologies utilized by minimally-invasive spine surgeons, but further studies are needed assessing its accuracy, complications, and cost-effectiveness.