Philip K. Louie

Study Design: Proof-of-concept simulation-based biomechanical pilot study. Objectives: To compare surgeon posture and muscle activity across four lateral lumbar interbody fusion (LLIF) positions and rank them by overall ergonomic burden. Methods: Five right-handed spine surgeons (case volumes 15 to 500 or more) each simulated a single-level LLIF on a synthetic model in four positions, three using direct vision (lateral decubitus, prone seated, prone lateral) and one using a camera and monitor (prone camera). Whole-body motion capture and surface EMG were recorded simultaneously, analyzed by surgical phase, and summarized per surgeon. Results: Neck-flexion intensity was greatest in lateral decubitus and lower in every prone position, with the same ranking in all five surgeons (exact Friedman p=3.0e-06, Kendall W=1.00). Arm elevation was highest in prone seated. Across four summaries of posture and muscle activity, prone camera was the most favorable position in every surgeon, while the others reordered by measure. All positions scored medium-to-high risk. No two-position comparison reached adjusted significance, as expected at this sample size. Conclusions: Patient position in LLIF does not appear to change patient outcome, but it changes what the operation costs the surgeon. Lateral decubitus loaded the neck in every surgeon regardless of case volume or preference, prone seated loaded the shoulder, and prone camera was most favorable overall . Surgeons can reduce their exposure through position and setup, and ergonomics offers an objective way to compare setups when patient outcomes cannot separate them. These are proof-of-concept findings in five surgeons and require confirmation in a larger sample.

Adult reconstruction and adult spine surgeons practicing at Medicare-participating hospitals face expanding exposure to mandatory value-based payment models. The Transforming Episode Accountability Model began on January 1, 2026, in approximately 741 hospitals across 188 core-based statistical areas and includes lower-extremity joint replacement and spinal fusion among its 5 surgical episodes. The Expanded Comprehensive Care for Joint Replacement Model has been proposed for nationwide implementation by 2028. Pediatric orthopaedic practice and other subspecialties that primarily serve non-Medicare populations have limited direct exposure to these specific programs. Physician engagement in governance structures, including comanagement arrangements and clinically integrated networks, has been associated with more favorable clinical and financial outcomes under bundled payment programs. When evaluating value-based contracts, relevant considerations include the methodology for distributing reconciliation payments, risk-adjustment approach for both target prices and individual performance, and governance authority over protocol development and implant selection. The Centers for Medicare and Medicaid Services has finalized a mandatory patient-reported outcome measure for elective primary total hip and knee arthroplasty, with reporting beginning in the 2028 calendar year and tied to hospital payment determinations. The measure requires paired preoperative and 1-year postoperative outcome data from a majority of eligible patients. Comparable measures are anticipated for adult spine and other adult orthopaedic procedures over time. Pediatric orthopaedic practices are not subject to this measure in its current form. Early bundled payment programs achieved savings primarily through reductions in postacute care utilization, with complication, readmission, and mortality rates functioning as quality safeguards on that spending focus. A more complete framework for value measurement organizes metrics across a tiered hierarchy spanning care processes, short-term utilization and cost, intermediate clinical outcomes, and long-term patient-reported outcomes. The framework applies conceptually across orthopaedic subspecialties, including pediatrics, though current programs from the Center for Medicare and Medicaid Innovation incorporate its elements primarily in adult reconstruction and adult spine care.

Study Design: Anonymous, survey-based study. Objective: The primary objective of this study is to understand and assess the factors influencing the choice of cervical fusion, disc arthroplasty, and hybrid procedures for radiculopathy in the setting of 2-level cervical degenerative pathology. Summary of Background Data: Anterior cervical discectomy and fusion (ACDF) has long been the gold standard for treating cervical degenerative pathologies. Cervical disc arthroplasty (CDA) usage has rapidly increased over the past decade, but hybrid constructs (a combination of ACDF and an adjacent disc arthroplasty) are rarely performed. Methods: A multidimensional survey (designed using a modified Delphi approach) was distributed worldwide to surgeons in the AO Spine membership. Questions were focused on surgical preferences, challenges, and barriers with various anterior cervical techniques. Imaging studies of several patients presenting with radiculopathy and 2-level cervical degenerative pathology were presented to assess surgical recommendations. Results: A total of 267 surgeons participated in this survey, representing 5 regions worldwide. The majority of participants practice in Europe and Southern Africa (31.5%), followed by Asia Pacific (27.3%), North America (16.5%), Latin America (15.7%), and the Middle East and Northern Africa (8.9%). When presented with 2-level degenerative conditions, ACDF represents the most frequently selected individual surgical option (45.75% among the 4 clinical cases). However, substantial variability exists, with many surgeons favoring motion-preserving or hybrid approaches depending on clinical context. Preservation of motion at the index level (71.7%) and the absence of adjacent segment disease (71.7%) were considered advantages of a hybrid construct compared with a 2-level ACDF. Respondents considered that the more advantageous location of CDA would be based on the clinical scenario, with CDA preferred above the ACDF level. Conclusion: When considering anterior cervical approaches to address radiculopathy, cervical fusions remain far more commonly performed globally, compared with CDA for 2-level degenerative cervical pathology. Despite their potential advantages in preserving motion and reducing adjacent-segment degeneration, hybrid procedures are less frequently performed, and fewer surgeons consider themselves experts in this technique. Level of Evidence: Level V.

OBJECTIVE: Precise restoration of sagittal balance is a critical goal in adult spinal deformity surgery. Computer-assisted planning allows for patient-specific alignment targets and rod pre-bending, theoretically improving the accuracy of surgical correction. However, the correlation between planned and achieved alignment goals using pre-bent rods remains unclear. The aim of this study was to evaluate the accuracy of alignment correction in patients undergoing lumbar pedicle subtraction osteotomy (PSO) using UNiD-derived pre-bent rods, and to compare software-generated preoperative alignment targets with actual postoperative radiographic parameters. METHODS: A retrospective cohort study was performed of adults who underwent lumbar PSO with long-segment thoracolumbar fusion (≥ 6 levels) at a single academic center between 2018 and 2022. Inclusion criteria required UNiD preoperative planning, PSO performed at the planned level, use of patient-specific pre-bent rods, and complete radiographic data. Planned alignment targets were obtained from the UNiD platform and compared with immediate postoperative standing lateral radiographs. Absolute differences between preoperative-to-planned and preoperative-to-postoperative values were compared using paired t-tests. Effect sizes (Cohen’s d) were calculated and post hoc power analysis was performed, with primary focus on pelvic incidence (PI), sagittal vertical axis, pelvic tilt, and PI minus lumbar lordosis (PI-LL). RESULTS: Twenty patients (60% female, median age 66.8 years) were included. The planned PSO angle closely matched the achieved correction (mean −24.2° planned vs −24.02° ± 7.31° postoperative, p = 0.94). Lumbar lordosis and L4–S1 lordosis exceeded planned correction, with a significant but modest increase at L4–S1 (p = 0.03). Pelvic parameters demonstrated the largest deviations from plan. Pelvic tilt correction exceeded predictions by a mean of 8.97° ± 7.10° (p < 0.01); the sagittal vertical axis was undercorrected by a mean of 36.37 ± 48.30 mm (p < 0.01); and PI changed more than anticipated (p = 0.01). PI-LL improved substantially from a mean of 29.73° ± 15.76° preoperatively to −3.23° ± 10.95° postoperatively (p < 0.001). The planned and achieved L1 pelvic angle did not differ significantly. CONCLUSIONS: Computer-assisted planning with patient-specific rods accurately reproduced the intended PSO and segmental lumbar correction but did not reliably predict global sagittal parameters. These findings suggest that current planning tools might require refinement to improve the accuracy of predicted postoperative alignment using pre-bent rods and to minimize the risk of suboptimal outcomes.

Study Design.: Retrospective cohort study. Objective.: To assess iatrogenic sagittal malalignment after short-segment lumbar fusions at L4–5, L5–S1, and L4–S1 using segmental alignment criteria and identify preoperative predictors. Summary of Background Data.: PI–LL mismatch is commonly used to assess sagittal correction after lumbar fusion, but may mask segmental under-correction due to compensatory mechanisms, risking iatrogenic flatback deformity. Methods.: A multicenter database of patients undergoing fusion at L4–5, L5–S1, or L4–S1 was retrospectively analyzed. Global alignment was defined as PI–LL P <.001). Segmental assessment also revealed markedly higher worsening rates at L5–S1 (44.2% vs. 12.5%) and L4–S1 (55.1% vs. 22.4%; both P <.001), while rates were identical at L4–5 (20.2% vs. 20.2%, P =1.0). Anterior interbody approaches and greater preoperative segmental lordosis predicted restoration; baseline lumbar lordosis was the only independent predictor of preserved alignment at L5–S1 (OR 1.25, 95% CI 1.05–1.49, P =.01). Conclusion.: Segmental assessment revealed substantially higher rates of malalignment and postoperative worsening than PI–LL alone, particularly in fusions including L5–S1. Anterior interbody techniques and greater preoperative lordosis were associated with improved correction. Surgeons should incorporate segmental alignment targets when planning distal lumbar fusions to avoid inadvertent flatback deformity.

Was not provided for this article.

Objective: Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are increasingly prescribed for type 2 diabetes mellitus and obesity. Their metabolic, anti-inflammatory, and osteogenic effects raise important questions regarding their influence on spinal fusion. To date, no systematic review has specifically investigated how GLP-1RAs influence outcomes following the common anterior cervical discectomy and fusion (ACDF). This study aimed to evaluate the association between perioperative GLP-1RA use and outcomes following ACDF. Methods: Following PRISMA guidelines, MEDLINE, Embase, PubMed, and the Cochrane Library were searched from inception to February 2026 for studies evaluating GLP-1RA exposure in the context of ACDF. Eligible studies included human observational cohort studies. Data were extracted independently by two reviewers. Results: Eight retrospective cohort studies analysing 311,402 ACDF patients were included, of whom 8,182 were GLP-1RA users matched to non-users. Random-effects meta-analysis demonstrated significantly lower odds of pseudarthrosis among GLP-1RA users at 6 months (OR = 0.60, 95% CI: 0.52 to 0.71; I² = 16.6%), 12 months (OR = 0.62, 95% CI: 0.53 to 0.73; I² = 39.1%), and 24 months (OR = 0.67, 95% CI: 0.57 to 0.79; I² = 34.9%). Findings for reoperation, dysphagia, deep vein thrombosis, and readmission were heterogeneous and inconsistent across studies. Conclusion: Perioperative GLP-1RA use was associated with lower odds of pseudarthrosis. However, evidence regarding other postoperative complications remains inconclusive. Future prospective studies are required to further elucidate the impact of GLP-1RA use on ACDF outcomes. Level of evidence: Level III, therapeutic study.

Study Design.: Retrospective single-institution cohort study. Objective.: To characterize intraoperative supply cost variability across surgeons and procedural levels in 1- and 2-level ACDF using impact scores, and to describe within-procedure value using time-driven activity-based costing (TDABC), the Operative Value Index (OVI), and Unit Price per Outcome (UPO). Summary of Background Data.: Intraoperative supply costs in ACDF vary widely and are dominated by implant selection, yet absolute cost figures are institution-specific and cannot be compared across sites. Impact scores express each supply category’s proportional share of total intraoperative supply cost, enabling normalized benchmarking independent of pricing. Methods.: A retrospective review of 369 ACDF cases (Current Procedural Terminology [CPT] code 22551, 1- and 2-level) performed by five surgeons was conducted. Supply items were categorized and impact scores calculated as each category’s share of total intraoperative supply cost (0 to 100 per case). Staff costs were estimated using TDABC. Neck Disability Index (NDI) and quality-adjusted life year (QALY) were collected at baseline and up to 12 months. OVI and UPO were derived from NDI and total intraoperative cost. Results.: Demographics were similar between groups. The five highest-impact categories for 1-level ACDF were interbody (30.9%), plate (27.8%), retractor/dilator (17.4%), screw (13.8%), and drill (12.5%); for 2-level: interbody (40.9%), plate (22.1%), screw (13.8%), retractor/dilator (12.7%), and drill (9.6%). Interbody scores increased significantly with level ( P <0.001). Biologic and interbody categories showed the greatest inter-surgeon variability. OVI and UPO varied more than 2.5-fold across surgeons performing the same procedure. Conclusion.: Impact scores reveal that interbody devices dominate ACDF supply cost and grow with added levels, while biologics exhibit the greatest inter-surgeon variability. OVI and UPO provide within-procedure value benchmarks independent of institutional pricing.