Objective Proximal junctional kyphosis (PJK) is a frequent postoperative complication following adult spinal deformity (ASD) surgery, whereas proximal junctional failure (PJF) is a less common but clinically more severe complication. Spinopelvic radiographic parameters have been associated with the development of these complications, yet existing studies have reported inconsistent results. This study aimed to investigate the association between spinopelvic parameters and proximal junctional complications (PJK/PJF), including analysis based on age-adjusted pelvic incidence (PI)–lumbar lordosis (LL) mismatch categories.
Methods This review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) 2020 guidelines. PubMed, Cochrane Library, and Embase were comprehensively searched from inception through March 2025. Adults (>18 years) who underwent surgery for ASD or long-segment (≥4 levels) spinal fusion were included. Studies were independently selected by 2 reviewers based on preset criteria. Random-effects model was used to calculate mean differences/standardized mean differences for continuous variables and odds ratios (ORs) for categorical outcomes.
Results A total of 47 retrospective studies were included in the meta-analysis. Preoperatively, the PJK group had lower LL and sacral slope (SS) but had higher pelvic tilt (PT), T1PA, and C7-sagittal vertical axis than the non-PJK group. Postoperatively, the PJK group showed significantly lower PI–LL mismatch values and SS and higher PT, thoracic kyphosis, thoracolumbar kyphosis, and T1 pelvic angle. When stratified by the age-adjusted PI–LL formula, overcorrection was associated with significantly higher odds of PJK (OR, 2.67; 95% confidence interval [CI], 1.61–4.42), whereas no significant association was observed for PJF. Using age-specific thresholds, overcorrection was significantly associated with higher odds of PJF (OR, 1.67; 95% CI, 1.10–2.52).
Conclusion Preoperative sagittal imbalance and postoperative spinopelvic differences were associated with proximal junctional complications, whereas associations for PJF were more limited. Age-adjusted overcorrection showed outcome-specific associations with proximal junctional complications, suggesting that age-tailored alignment may be clinically relevant. Given the retrospective aggregate evidence and limited age-adjusted data, future prospective studies with standardized radiographic timing and separate outcome assessment for PJK and PJF are needed to validate these findings.
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Reliability of the Biomechanical Assessment of the Sagittal Thoracic Spine on Radiographs Used in Clinical Practice: A Systematic Literature Review Joseph W. Betz, Douglas F. Lightstone, Jason W. Haas, Paul A. Oakley, Joseph R. Ferrantelli, Ibrahim M. Moustafa, Deed E. Harrison Bioengineering.2026; 13(9): 966. CrossRef
Sara Lener, Raphael Gmeiner, Anto Abramovic, Anna Koller, Christoph Orban, Sebastian Hartmann, Alexandra Grob, Victor Staartjes, Ann Kathrin Joerger, Carolin Albrecht, Bernhard Meyer, Felipa Lange, Andreas Kramer, Florian Ringel, Christopher Marvin Jesse, Ralph T. Schär, Christoph Bettag, Veit Rohde, Insa K. Janssen, Karl Schaller, Julia Onken, Aminaa Sanchin, Peter Vajkoczy, Imran Shah, Rebecca Sutherland, Andreas K. Demetriades, Claudius Thomé
Neurospine 2026;23(3):625-632. Published online July 31, 2026
Objective Spinal infection (SI) is associated with substantial morbidity and mortality, and optimal treatment strategies remain debated, particularly in medically fragile patients. The Mortality in Spinal Infection (MSI-20) score was developed as the first dedicated prognostic tool for mortality risk estimation, but external validation in large cohorts has been lacking. This study aimed to externally validate the MSI-20 in a large multicenter registry cohort and assess its performance, clinical thresholds, and generalizability.
Methods This retrospective multi-institutional registry study included 1,122 adult patients with clinically, radiologically, and laboratory-confirmed SI treated at 6 tertiary referral centers between 2010 and 2023. The multicenter registry design enabled robust analysis of this relatively rare outcome. MSI-20 scores were calculated according to the original definition. Predictive performance was evaluated using receiver operating characteristic (ROC) analysis with 95% confidence intervals. Mortality across score strata and center-wise performance were analyzed, with exploratory assessment of additional baseline predictors.
Results Mean age was 66.4±13.1 years, and overall mortality was 18.3%. The MSI-20 demonstrated fair discriminative ability (area under the curve [AUC], 0.68; 95% confidence interval [CI], 64–72). The optimal ROC threshold was 3.5; a cutoff ≥4 yielded sensitivity 0.49 and specificity 0.74 (F1 score, 0.38). Mortality increased progressively, approaching 50% (47.4%) at scores ≥9. Performance was consistent across centers (AUC, 0.60–0.75). Exploratory univariable analyses did not identify additional baseline variables with consistent strong associations beyond the MSI-20 components.
Conclusion This large multicenter registry study provides the first external validation of the MSI-20, confirming reproducibility and generalizability. The score demonstrated fair discrimination and a clear risk gradient across increasing score categories. Given its simplicity and high negative predictive value, the MSI-20 may serve as an adjunctive tool to support risk communication, multidisciplinary discussion, patient counseling, and preoperative optimization in spinal infection.
Objective To investigate feasibility and effectiveness of minimally invasive scoliosis surgery (MISS) via posterior approach in patients with adolescent idiopathic scoliosis (AIS) presenting with very severe curve exceeding 80°.
Methods A total of 257 flexible AIS patients who underwent deformity correction using posterior MISS were retrospectively categorized into 3 groups based on the curve magnitude: moderate (M group, main Cobb angle <60°, n=142), severe (S group, 60°–80°, n=91), and very severe (VS group, ≥80°, n=24). Radiological parameters, perioperative outcomes, and complication rates were compared among the 3 groups.
Results The VS group required significantly longer operative times (p<0.001), more fused segments (p<0.001), and a greater number of rib resections during thoracoplasty (p=0.032) compared to the other groups. Despite these surgical demands, there were no statistical differences in the correction rate (p=0.954) and last follow-up thoracic kyphosis (p=0.830) among the 3 groups. Regarding complications, while the overall complication rate showed no statistical difference, the VS group required significantly more invasive management for pleural effusions (p=0.012).
Conclusion Posterior MISS demonstrated acceptable radiological and perioperative outcomes even in flexible AIS with Cobb angles ≥80°. These findings suggest the posterior MISS can be a feasible surgical option for selected very severe AIS patients with sufficient flexibility.
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From the Editor-in-Chief: Featured Articles in the July 2026 Issue Inbo Han Neurospine.2026; 23(3): 513. CrossRef
A Commentary on “Feasibility of Minimally Invasive Scoliosis Surgery in Adolescent Idiopathic Scoliosis Exceeding 80° of Curve Magnitude” Ibrahim Obeid Neurospine.2026; 23(3): 577. CrossRef
Objective This study aims to compare the risk of subsequent surgery following surgical treatment of clinical adjacent-segment pathology (CASP) after lumbar fusion, specifically evaluating decompression alone versus decompression with extension of the fusion.
Methods Using the Swespine registry, we included patients who had surgical treatment for CASP following index lumbar fusion surgery, 1997–2019. The cohort was divided according to CASP treatment: decompression alone or decompression with extended fusion. A comparison of subsequent surgeries was made with Kaplan-Meier analysis and Cox regressions adjusted for potential confounders (age, sex, body mass index, smoking status, number of operated levels at CASP surgery, number of fused levels at index fusion surgery, and diagnosis for CASP surgery).
Results A total of 2,521 patients were included, 1,176 (47%) in the decompression-group and 1,345 (53%) in the extended fusion group and the mean follow-up was 6.1±4.4 years. Mean age at CASP surgery was 61 years and 1,588 (63%) were females. The median time to subsequent surgery was 1.7 years (range, 0.9–3.7 years). Kaplan-Meier–estimated probability of subsequent surgeries at 5 years was 18% (95% confidence interval [CI], 15%–20%) for the decompression-group and 25% (95% CI, 22%–27%) for the extended fusion group. The hazard ratio was 1.26 (95% CI, 1.02–1.56; p=0.032) for those with extended fusion.
Conclusion Extension of fusion for CASP was associated with significantly higher risk of subsequent surgery, but causality should be interpreted with caution as radiographic information on instability, deformity, or foraminal stenosis could not be verified.
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A Commentary on “How to Treat Adjacent-Segment Pathology Following Lumbar Fusion Surgery: Decompression Alone or Decompression With Extended Fusion Surgery?” Jang W. Yoon Neurospine.2026; 23(3): 564. CrossRef
When Is Fusion Necessary in Addressing Symptomatic Adjacent Level Pathology – A Commentary on “How to Treat Adjacent-Segment Pathology Following Lumbar Fusion Surgery: Decompression Alone or Decompression With Extended Fusion Surgery?” Marc A. Arslanian, Vignessh Kumar, Lee A. Tan Neurospine.2026; 23(3): 561. CrossRef
From the Editor-in-Chief: Featured Articles in the July 2026 Issue Inbo Han Neurospine.2026; 23(3): 513. CrossRef
Objective Advanced age has been proposed as a risk factor for worse outcomes and higher complication rates after spinal surgery. We assessed whether decompression for central lumbar spinal stenosis (CLSS) provided meaningful improvement in patients aged 50–95 years.
Methods We evaluated preoperative and 1-year postoperative Numerical Rating Scale (NRS) leg and back pain, Oswestry Disability Index (ODI), and complications in 17,987 patients aged ≥50 years undergoing decompression without fusion for CLSS without spondylolisthesis from the Swespine register. Meaningful improvement was defined using minimal clinically important difference (MCID) thresholds for NRS leg/back pain and ODI. Across 5-year age groups, we assessed the proportions improving ≥MCID and odds ratios (ORs) with 95% confidence intervals (CIs), using ages 65–69 years as the reference group.
Results Across age groups, 71%–80% improved ≥MCID in ≥1 outcome. Compared with the reference group, ORs (95% CI) for ≥MCID improvement were lower in ages 70–74 (0.8; 0.7–1.0), 75–79 (0.7; 0.6–0.8), 80–84 (0.6; 0.5–0.7), and 85–89 (0.6; 0.5–0.8); no other age groups differed. 5%–12% experienced complications. Compared with the reference group, ORs (95% CI) for complications were higher in ages 75–79 (1.3; 1.1–1.6), 80–84 (1.7; 1.4–2.1), and 85–89 (2.0; 1.5–2.8), and lower in ages 55–59 (0.7; 0.5–0.9).
Conclusion 77% of patients aged 50–95 years improved ≥MCID after decompression without fusion for CLSS without spondylolisthesis. Although outcomes were slightly worse and complication rates higher in older than younger patients, decompression without fusion remains effective across this age range.
Objective Accurate segmentation of surgical instruments in endoscopic images is essential for developing computer-assisted surgical systems, yet creating annotated training datasets remains labor-intensive. This study aimed to evaluate the efficiency of point-based interactive segmentation using foundation models for surgical instrument annotation in spinal endoscopy.
Methods We conducted a retrospective study comparing point-based segmentation performance between Segment Anything Model (SAM) 2.0, SAM 2.1, and domain-adapted MedSAM 2.1 for surgical instrument segmentation in spinal endoscopy. A test set of 308 images from 10 patients undergoing full-endoscopic lumbar decompression/discectomy or biportal endoscopic decompression/discectomy was evaluated. Models were assessed using standardized point prompts placed at the ground truth mask centroid. Primary outcomes included Dice similarity coefficient at single-click and success rate (Dice≥0.85). Secondary analysis evaluated click-to-quality metrics across iterative refinement up to 10 clicks.
Results At single-click, MedSAM 2.1 achieved significantly higher Dice scores than SAM 2.1 (0.937±0.074 vs. 0.844±0.222, p<0.001; 95% confidence interval [CI] for difference, 0.070–0.116) and SAM 2.0 (0.937±0.074 vs. 0.824±0.236, p<0.001; 95% CI for difference, 0.088–0.138), with a 3-fold reduction in variability (standard deviation: 0.074 vs. 0.222). External validation on the publicly available Spine Endoscopic Atlas dataset (202 images from 10 patients) confirmed generalizability, with MedSAM 2.1 achieving Dice 0.918±0.083, compared to 0.724±0.281 for SAM 2.1 and 0.708±0.290 for SAM 2.0 (both p<0.001). Interrater agreement between 2 independent annotators demonstrated excellent reliability (intraclass correlation coefficient, 0.991; 95% CI, 0.986–0.994; mean pairwise Dice, 0.953±0.051). The MedSAM 2.1-assisted workflow reduced annotation time by 75.8% compared to manual polygon annotation (7.7±13.3 seconds vs. 31.8±18.2 seconds per image; p<0.001; 4.1-fold speedup). SAM 2.1 improved progressively with additional clicks (Dice 0.844 to 0.943 at 10 clicks), while MedSAM 2.1 showed nonmonotonic progression (0.937 to 0.947), indicating near-optimal first-click predictions.
Conclusion Domain-adapted MedSAM 2.1 improved single-click annotation accuracy and efficiency for surgical instruments in spinal endoscopy, suggesting that low-resource domain adaptation may facilitate institutional dataset construction for surgical artificial intelligence research.
Vit Kotheeranurak, Jin-Sung Kim, Inbo Han, Hyeun-Sung Kim, Thanapol Ultarnpatumros, Chinati Puinongpo, Javier Quillo-Olvera, Lei Jiang, Christoph Siepe, Worawat Limthongkul, Weerasak Singhatanadgige, Surachat Jaroenwareekul
Neurospine 2026;23(3):605-624. Published online July 31, 2026
Objective Endoscopic spine surgery (ESS) has expanded rapidly, but existing spine registries do not consistently capture ESS-specific technical variables, ultra-early recovery trajectories, selective imaging validation, or dissemination-related learning-curve effects. This review synthesizes established spine registry models, contemporary consensus initiatives, and digital follow-up approaches to propose a candidate ESS-specific registry framework and preliminary Minimum Data Set (MDS) for future validation.
Methods A structured narrative review was conducted on national and multinational spine registries, relevant consensus initiatives, and digital follow-up models. Sources were reviewed with emphasis on governance, data architecture, workflow design, patient-reported outcome measures (PROMs) integration, follow-up structure, data linkage, validation strategies, and implementation feasibility.
Results Established registries provide a methodological foundation for benchmarking, complication surveillance, longitudinal PROM capture, and real-world evidence generation. However, ESS requires modular augmentation of existing registry infrastructures to capture approach-specific operative details, early recovery, selective imaging phenotypes, and governance-controlled maturity indicators. The proposed candidate MDS is organized into 4 domains: (1) baseline case-mix and phenotyping, (2) procedure-specific technical and perioperative variables, (3) selective quantitative imaging and morphometric validation, and (4) structured longitudinal outcome surveillance. The framework prioritizes an essential core dataset while separating recommended, optional, research-oriented, and governance-controlled modules, including digitally enabled early follow-up, opioid-related outcomes, radiation exposure, advanced imaging, and learning-curve variables.
Conclusion A candidate ESS-specific registry framework may support harmonized data capture, real-world evidence generation, quality feedback, and future registry-based research. Formal Delphi consensus, multicenter feasibility testing, and staged integration into existing spine registry infrastructures are required before broader implementation.
Objective This study aimed to determine the incidence of spinal infection after vertebral augmentation (SIAVA) and identify its independent risk factors.
Methods This multicenter, retrospective case-control study included patients who underwent percutaneous vertebral augmentation (PVA) for osteoporotic vertebral compression fractures at 4 centers between January 2015 and December 2021. Each SIAVA case was matched with 3 controls using propensity score matching based on demographic and clinical variables. LASSO (least absolute shrinkage and selection operator) regression was used for variable selection, followed by multivariable conditional logistic regression to identify risk factors for SIAVA.
Results Among 7,797 PVA procedures, 42 SIAVA cases were identified, yielding an incidence of 0.54%. The median time from PVA to SIAVA diagnosis was 4.3 (interquartile range, 2.8–11.7) weeks. After 1:3 matching (42 cases vs. 126 controls), multivariable analysis identified 4 independent risk factors: preoperative pulmonary infection (odds ratio [OR], 3.64; 95% confidence interval [CI], 1.21–11.0; p=0.022), intravertebral fluid sign on magnetic resonance imaging (MRI) (OR, 6.17; 95% CI, 1.92–19.9; p=0.002), type D (intradiscal) cement leakage (OR, 2.93; 95% CI, 1.10–7.85; p=0.032), and serum albumin ≤35 g/L (OR, 3.29; 95% CI, 1.15–9.45; p=0.027). Within the infection cohort, 25 patients (59.5%) underwent revision surgery, and 2 deaths (4.8%) occurred during follow-up.
Conclusion The incidence of SIAVA was 0.54%. Preoperative pulmonary infection, intravertebral fluid sign on MRI, type D cement leakage, and serum albumin ≤35 g/L were identified as independent risk factors. These findings may help clinicians implement preoperative risk-reduction strategies.
Objective To establish an adult-lifespan segment-specific normative atlas of cervical spinal cord morphometry as a physiologically adjusted reference and to explore its application in degenerative cervical myelopathy (DCM).
Methods We included 829 healthy volunteers and 210 surgically treated DCM patients undergoing cervical magnetic resonance imaging (MRI) from 2019 to 2023. Follow-up MRI was obtained in a stratified random sample of 207 healthy volunteers and 42 patients. Axial T2-weighted images at C2–3 to C6–7 were segmented semiautomatically. Cross-sectional area (CSA) was the primary morphometric measure; right-left and anteroposterior diameters (APDs) were complementary measures. In healthy volunteers, sex-stratified, level-specific models including age, age², magnetic field strength, and scanner manufacturer were used to construct the atlas and compute z-scores. In DCM, z-scores were summarized as CompMinZ and NonCompMinZ and explored in relation to clinical outcomes.
Results In healthy volunteers, CSA showed a nonlinear pattern, with smaller values at older ages. Longitudinal changes were age dependent: CSA, right-left diameter, and APD increased in younger adults, were stable in midlife, and declined in older adults. In DCM, z-scores were most negative at compressed levels, while noncompressed segments also frequently fell below the normative mean. Z-score metrics showed exploratory associations with neurological status and postoperative outcomes. In the postoperative subset, CompMinZ showed the strongest association with recovery rate, whereas maximum spinal cord compression was not significantly associated with recovery rate.
Conclusion An adult-lifespan, segment-specific normative atlas of cervical spinal cord morphometry provides a physiologically adjusted reference for interpreting cervical cord morphologic variation and deviation, with exploratory application in surgically treated DCM.
Objective Parkinson disease (PD) is frequently characterized by a forward-bent posture that increases biomechanical stress on the lumbar spine, which increases the rate of subsequent lumbar surgeries after spinal fusions. This study aimed to evaluate the rates of additional lumbar surgeries following spinal fusion in patients with PD.
Methods Data from the Health Insurance Review and Assessment Service of the Republic of Korea were retrospectively analyzed. PD was identified using the International Classification of Diseases, 10th Revision code G20. Patients with PD were matched with those without PD in a 3:1 ratio based on sex, age, and Charlson Comorbidity Index using the greedy nearest neighbor matching method. The primary outcome was the rate of subsequent lumbar surgeries following spinal fusion within the 7-year follow-up period. The timing of these reoperations was also assessed.
Results A total of 2,287 patients with PD and 6,861 matched patients without PD were included in this study. The prevalence of PD among patients undergoing lumbar fusion surgery remained stable throughout the study period. Patients with PD had 1.6-fold higher odds to undergo reoperation compared with the non-PD cohort. No significant difference was observed in the timing of additional surgeries between the groups.
Conclusion Patients with PD faced 1.6-fold higher odds of subsequent lumbar surgeries following spinal fusion compared to those without the disease. This finding suggests the need for a cautious treatment approach and thorough preoperative optimization when considering lumbar fusion in this population.
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A Commentary on “Rates of Subsequent Lumbar Surgery Following Spinal Fusion in Patients With Parkinson Disease: A Propensity-Score Matched Nationwide Cohort Analysis” Yusuke Nishimura Neurospine.2026; 23(3): 547. CrossRef
From the Editor-in-Chief: Featured Articles in the July 2026 Issue Inbo Han Neurospine.2026; 23(3): 513. CrossRef
Objective To evaluate early postoperative mobility after lumbar decompression using real-time location system (RTLS)-derived objective metrics and to explore differences in mobility patterns between biportal endoscopic decompression and open decompression.
Methods This retrospective cohort study included 323 patients who underwent lumbar decompression for degenerative lumbar spinal stenosis between March 2020 and May 2024. RTLS sensors embedded in wristbands continuously recorded patient mobility during postoperative days (PODs) 1–4. Primary RTLS-derived outcomes included total walking distance, mean walking speed, and active movement ratios (top 20% and top 50%). Between-group comparisons were performed using nonparametric tests. Propensity score matching and multivariable median quantile regression adjusting for age, American Society of Anesthesiologists physical status, and preoperative mobility were conducted.
Results RTLS identified differences in early postoperative activity patterns between surgical approaches. In adjusted analyses, activity-intensity–based metrics, particularly the top 20% activity ratio, remained significantly higher in the biportal endoscopic decompression group across multiple PODs. Subgroup analyses demonstrated minimal differences after single-level decompression, whereas activity-based differences were more frequently observed in multilevel procedures.
Conclusion RTLS-based continuous monitoring detected differences in early postoperative activity patterns following lumbar decompression. These findings support the role of RTLS as an objective tool for assessing early functional recovery in spine surgery.
Spine imaging represents a complex diagnostic frontier characterized by anatomical variability, motion artifacts, metallic instrumentation interference, and significant inter-reader diagnostic variability (κ=0.20 across institutions). While conventional discriminative artificial intelligence (AI) models achieve >95% accuracy in detecting degenerative changes, they remain limited by data scarcity, heterogeneous protocols, and poor generalizability. In the spine, these limitations are particularly relevant because clinical decisions can often depend on subtle distinctions (such as differentiating levels of canal or foraminal stenosis, characterizing Modic endplate changes, or assessing pedicle and vertebral morphology), where small inconsistencies can meaningfully alter management or surgical planning. Generative AI (GenAI) systems—including generative adversarial networks (GANs), diffusion models, and vision-language models (VLMs)—offer a paradigm shift by learning underlying data structures to generate high-quality synthetic outputs rather than merely classifying existing data. This narrative review, conducted using SANRA (scale for the assessment of narrative review articles) methodology across PubMed, Scopus, Embase, and Cochrane Library, examined GenAI applications in spine imaging. Eligible studies included observational designs through randomized controlled trials exploring image reconstruction, synthetic computed tomography (CT) generation, segmentation, and surgical planning applications. GAN-generated synthetic magnetic resonance imaging sequences reduce scan times by ~40% while maintaining diagnostic confidence; diffusion models enable radiation-free synthetic CT for preoperative planning; and VLMs generate structured radiology reports with hallucination rates <1.12%. However, critical barriers impede clinical translation: external validation gaps reveal AI performance collapse in real-world cohorts (sensitivity drops to 54.9% in cervical fracture detection); hallucinations and anatomical inaccuracies risk misguiding implant sizing; bias amplification magnifies demographic underrepresentation; and fragmented, small datasets lack standardized benchmarks. Technical fragility, computational demands, clinician trust deficits, and unresolved regulatory frameworks for iteratively-updating systems remain unaddressed. Successful integration requires coordinated development across 5 priorities: (1) multi-institutional datasets with cross-vendor harmonization, (2) federated learning frameworks preserving privacy, (3) uncertainty quantification and explainability tools, (4) outcome-linked clinical validation replacing technical metrics, and (5) workflow-integrated systems with DICOM-native interfaces and provenance tracking.
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A Commentary on “From Pixels to Precision: Generative Artificial Intelligence as a Paradigm Shift in Spine Imaging—Technical Foundations, Clinical Applications, and the Path to Safe Clinical Deployment” Fabrizio Russo, Luca Ambrosio, Gianluca Vadalà, Vincenzo Denaro Neurospine.2026; 23(2): 314. CrossRef
From the Editor-in-Chief: Featured Articles in the April 2026 Issue Inbo Han Neurospine.2026; 23(2): 227. CrossRef
Objective To evaluate whether combining clinical frailty with magnetic resonance imaging (MRI)-derived posterior paraspinal muscle degeneration identifies perioperative risk phenotypes in adults aged ≥75 years undergoing lumbar fusion.
Methods We retrospectively studied patients aged ≥75 years undergoing lumbar fusion with preoperative lumbar MRI. Frailty was assessed using the Fried phenotype (frail: score ≥3). Posterior paraspinal muscle degeneration across L1–S1 was quantified using automated segmentation and a composite posterior frailty index (PFI); severe degeneration was defined as the upper quartile of PFI. Patients were classified into 4 frailty×muscle phenotypes. Primary outcomes were any in-hospital complication and prolonged length of stay (LOS ≥16 days).
Results Among 248 patients, phenotypes A–D (A, nonfrail/nonsevere; B, frail/nonsevere; C, nonfrail/severe; D, frail/severe) comprised 132, 54, 20, and 42 patients, respectively. Any in-hospital complication occurred in 18.2% of phenotype A compared with 50.0%–57.1% in phenotypes B–D (p<0.001). Prolonged LOS (≥16 days; cohort 75th percentile) occurred in 0.8% of phenotype A versus 38.9% (B), 35.0% (C), and 78.6% (D) (p<0.001), corresponding to absolute risk increases of +34.2 to +77.8 percentage points. After adjustment, higher-risk phenotypes remained independently associated with increased odds of any complication and prolonged LOS; however, the prolonged-LOS odds estimates were imprecise due to sparse events in the reference group. Phenotype was not independently associated with 90-day readmission. Pain improvement (ΔVAS [visual analogue scale]) was attenuated in phenotypes B and D, while differences in ΔODI (Oswestry Disability Index) were not statistically significant.
Conclusion Integrating frailty and MRI-based posterior paraspinal degeneration provides actionable stratification of complication and prolonged LOS risk after lumbar fusion in older adults.
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From the Editor-in-Chief: Featured Articles in the April 2026 Issue Inbo Han Neurospine.2026; 23(2): 227. CrossRef
A Commentary on “Frailty-Muscle Phenotypes Predict Outcomes After Lumbar Fusion in Adults Aged ≥75 Years: A Retrospective Cohort Study” Julie L. Chan, Daniel J. Hoh Neurospine.2026; 23(2): 255. CrossRef
Objective To determine the role of dynamic hip joint coverage in maintaining postoperative sagittal balance in adult spinal deformity (ASD) patients following S2-alar-iliac (S2AI) fixation.
Methods A total of 224 ASD patients who underwent S2AI fixation were enrolled. Patients were stratified into 2 groups based on pre-to-post (from preoperative to postoperative) changes in femoral head coverage (ΔFHC): change group (group C) and noncoverage change group (group NC). Group C was further subdivided according to FHC recovery during follow-up into rebound (group C-R) and nonrebound (group C-NR) groups. Clinical outcomes and radiographic parameters of hip and spinopelvic alignment were assessed preoperatively, at the initial postoperative standing, and at the 2-year follow-up.
Results Compared to group C, patients in group NC demonstrated a higher incidence of sagittal imbalance-related mechanical complications at 2-year follow-up, with a greater tendency for sagittal imbalance progression (p=0.013), a larger post-to-follow-up change in sagittal vertical axis (ΔSVA) (p=0.029), and a higher incidence of proximal junctional kyphosis (PJK) (p=0.031). Although there was no significant difference in PJK incidence between group C-NR and group C-R (p=0.845), group C-NR showed a greater tendency for postoperative sagittal imbalance aggravation (p=0.025), with a significantly larger ΔSVA during follow-up (p=0.002). The optimal cutoff values for predicting postoperative sagittal imbalance aggravation were 3.5% for pre-to-post ΔFHC (area under the curve [AUC]=0.694) and 1.8% for post-to-follow-up ΔFHC (AUC=0.713).
Conclusion Dynamic postoperative changes in hip joint coverage, characterized by the FHC, are associated with postoperative sagittal balance maintenance. Patients with limited pre-to-post and post-to-follow-up changes in the FHC demonstrate compromised hip joint compensatory capacity, thereby increasing the risk of postoperative sagittal imbalance-related mechanical complications.
Objective To longitudinally analyze smartphone-based real-life activity data and compare it with established clinical outcome measures in patients undergoing lumbar spine surgery for sciatica, focusing on identifying divergence in recovery trajectories.
Methods Fifty patients were assessed preoperatively and at 6 weeks (6W), 3 months (3M), and 6 months (6M). Outcomes included smartphone-derived daily Step Count, objective capacity (6-minute walking test [6WT]), and subjective disability (visual analogue scale [VAS] leg/back, Core Outcome Measures Index [COMI] back, and Oswestry Disability Index [ODI]). All metrics were standardized into z-scores relative to baseline. Piecewise linear mixed-effects (LME) models compared recovery slopes across 2 segments: phase I (early: 0–6 weeks) and phase II (late: 6 weeks–6 months).
Results The cohort (mean age, 50.7 years; 24 females) included 33 patients with lumbar disc herniation and 17 with lateral recess stenosis. All measures improved significantly during phase I (all p<0.05). However, LME modeling revealed a significant interaction between time segment and measurement type in phase II. Daily Step Count was the only metric maintaining a significant, linear upward recovery slope during the late phase (β=0.31 Z/mo). Conversely, slopes for 6WT, ODI, and COMI were significantly flatter (p<0.001 vs. Step Count), indicating a statistical plateau or “ceiling effect.” Spearman correlations between Step Count and traditional metrics weakened from strong at baseline to weak at 6 months.
Conclusion Smartphone-derived real-life activity data detect continuous functional improvement up 6 months postoperatively, whereas conventional objective and subjective measures plateau by 6 weeks. Real-world activity monitoring provides a more sensitive assessment of long-term surgical success.
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From the Editor-in-Chief: Featured Articles in the April 2026 Issue Inbo Han Neurospine.2026; 23(2): 227. CrossRef
Real-World Effectiveness Versus Efficacy in a Study Environment: How Smartphones Help Capture Meaningful Patient Recovery Trajectories – A Commentary on “Physical Performance Continues to Improve After Surgery for Sciatica, Exceeding Recovery Periods of P Victor E. Staartjes Neurospine.2026; 23(2): 239. CrossRef
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