Imaging, physical examination, and patient-reported outcome measures (PROMs) remain central to spine care but incompletely characterize how spinal disease affects physical performance and how function changes following treatment. Objective assessment of gait, balance, functional transitions, lifting, and neuromuscular control provides complementary information regarding movement impairment, compensation, and recovery. This narrative review synthesizes current evidence supporting objective functional assessment in spine care and proposes Disability and Functional Outcome Measures (DFOMs) as a translational framework for organizing these measurements into clinically interpretable functional domains. DFOMs are not presented as a new measurement instrument or independently validated composite outcome; rather, the framework integrates established and emerging objective functional measures acquired through motion analysis, force platforms, electromyography, wearable sensors, and markerless technologies. Evidence supporting individual measures varies substantially with respect to validity, reliability, responsiveness, normative reference values, and clinical utility. Laboratory-based gait and balance assessment currently have the strongest evidence base, whereas multidomain composite scoring, markerless assessment, wearable-derived biomarkers, and artificial intelligence-enabled phenotyping remain at earlier stages of clinical translation. Objective functional phenotyping may ultimately complement structural and patient-reported assessment by providing a multidimensional characterization of disability and recovery. However, standardized protocols, multicenter validation, clinically meaningful thresholds, implementation studies, and evidence of incremental clinical utility are required before widespread adoption in routine spine care.

Background Context Rod breakage is a frequent and clinically important late complication after adult spine deformity (ASD) surgery, yet most research has focused on patient and alignment factors rather than implant geometry. Purpose This study aimed to investigate the rod-related characteristics independently associated with rod breakage following ASD surgery, with particular focus on quantitative measures of rod material, rod shape and its postoperative evolution. Design Retrospective analysis of prospectively collected, six-center data. Patient Sample ASD patients, who underwent long posterior fusion to the pelvis with available serial full-length lateral radiographs at 6 weeks, 6 months, 1 year, and 2 years were included; patients with multiple-rod constructs were excluded. Minimum two-year follow-up. Outcome Measures Rod breakage (defined radiographically), time to rod breakage, and discrimination performance of a multivariable predictive model based on patient and rod characteristics. Methods Rod curvature was quantified at L1-S1 and L4-S1 and the maximum positive increase in L1-S1 curvature between consecutive postoperative timepoints was derived. Time-to-breakage was analyzed using Kaplan-Meier and Cox proportional hazards models, with data-driven thresholds defining high-risk geometry. Model discrimination was assessed using the concordance index. Results Eighty-three patients (mean follow-up 60.0 ± 23.0 months) were analyzed; 30 developed rod breakage at a mean 41.7 ± 22.2 months. L4-S1 rod curvature ≥33° at 6 weeks was associated with higher risk of breakage (HR 2.25; 95% CI 1.06-4.77; p = 0.036), as was a maximum L1-S1 curvature increase≤4° (HR 3.33; 95% CI 1.25-8.84; p = 0.016). Titanium rods had lower risk compared with cobalt-chromium (HR for titanium 0.50; p = 0.02), and diameter >5.5 mm was associated with increased risk (HR 1.90; p = 0.02). A multivariable patient-level model incorporating rod geometry showed improved discrimination (C-index 0.74). Conclusions Specific rod geometry characteristics-particularly early lower lumbar curvature and limited postoperative curvature increase-were independently associated with rod breakage after ASD surgery. Integrating rod shape into risk models may support implant selection, surgical planning, and postoperative monitoring. Level of Evidence Level III, retrospective cohort study.

The rapid expansion of minimally invasive, endoscopic, percutaneous, and implant-based spine interventions has outpaced standardized training requirements. This statement provides recommendations based on current training pathways, contemporary practice, and expert consensus, with patient safety as the guiding principle. These recommendations are not intended to define or restrict scope of practice; credentialing decisions remain the responsibility of institutions and governing bodies. Formal surgical spine training currently occurs through orthopaedic surgery residency with spine fellowship or neurological surgery residency with or without spine fellowship. These pathways include substantial supervised operative experience and ACGME residency case minimums. Anesthesiology, physical medicine and rehabilitation, radiology, and pain medicine pathways provide procedural training but do not include operative spine training, and nationally recognized training pathways for these specialties do not have minimum required case volumes across the spectrum of advanced spine interventions. Minimum case numbers, where established, are only one component of competency and should be considered alongside appropriate education, supervised experience, and demonstrated competency. Training and credentialing should reflect procedural complexity, anatomy at risk, biomechanical alteration, and potential complications. A surgical intervention treats structural spinal anatomy and meaningfully alters biomechanics or directly visualizes and decompresses the spinal cord and/or nerve roots. Based on current training pathways, spinal fusion or permanent stabilization, direct spinal cord and/or nerve root decompression, lateral sacroiliac fusion, vertebral augmentation with structural vertebral implants beyond cement or bone graft, and spinal cord stimulation paddle lead placement should be performed by physicians with formal surgical spine training. Other non-structural interventions, including basivertebral nerve ablation, percutaneous neuromodulation, cement or bone-graft vertebral augmentation, and endoscopic branch neurectomy, should require structured procedure-specific education, supervised experience, appropriate minimum case numbers, and competency assessment. Educational courses should complement rather than replace structured clinical experience. This statement encourages prospective registries for emerging technologies to evaluate outcomes, complications, reinterventions, durability, subsequent surgical consequences, and inform training standards. Transparent informed consent and documented complication-management arrangements established before the procedure in every practice setting, including physician offices, are essential.