Spine Journal - 2026-04-14 - Journal Article
Complications of Spinal Fusion: Comparing Medicare Transforming Episode Accountability (TEAM) Hospitals to Control Hospitals.
Martin BI, Mirza SK, Ko H, Karamian B
Topics
Key Takeaway
TEAM participant and non-participant hospitals had statistically equivalent 30-day complication rates (inpatient composite 28.2%, outpatient 10.4%), with ~94% of outcome variance attributable to patient-level rather than institutional factors.
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Summary
This study compared 30-day readmission and complication rates across 18 TEAM-defined spinal fusion categories between TEAM participant and non-participant hospitals using multilevel logistic regression with hospital-level random effects. Inpatient readmission (8.9%, OR 1.01), outpatient readmission (5.7%, OR 0.87), and composite complication rates were statistically equivalent between groups. Hospital-level ICC was low (1.06% for readmission, 3.61% for complications), with TEAM adjusters explaining 61.6% of hospital variance for readmission but only 36.6% for complications, and expanded socioeconomic and surgical covariates adding minimal incremental explanatory power.
Key Limitation
TEAM adjusters explained only 36.6% of hospital-level variance in composite complications, leaving substantial unexplained variation that may reflect unmeasured confounders such as surgical volume, implant selection, or surgeon-level factors not captured in claims data.
Original Abstract
BACKGROUND CONTEXT
Medicare's Transforming Episode Accountability Model (TEAM) holds hospitals accountable for 30-day post-operative complication across 18 categories of spinal fusion bundles, yet baseline differences in complication rates between participant and non-participant hospitals may confound policy evaluation and performance under this model.
PURPOSE
We compared complication rates for 18 TEAM-defined categories of fusion between participant and non-participant hospitals, and characterized patient- and hospital-level factors contributing to variation.
STUDY DESIGN/SETTING
Retrospective cohort study of Medicare beneficiaries undergoing inpatient or hospital outpatient lumbar and cervical fusion.
PATIENT SAMPLE
Fee-for-service Medicare beneficiaries undergoing spinal fusion (2016-2021) were included. Excluded were Medicare Advantage, United Mine Workers, Maryland hospitals, and patients undergoing complex fusions (8+ vertebral levels, or fusion for primary diagnosis of spinal curvature, malignancy, infection).
OUTCOME MEASURES
THIRTY DAY POST-DISCHARGE
all-cause readmission and post-operative complications (cardiac, vascular, infection, thromboembolic, cerebrovascular and device-related).
METHODS
We linked hospital TEAM participants to fee-for-service Medicare fusion claims and calculated 30-day complications by fusion category. Complication rates were estimated using multilevel logistic regression with a hospital-level random effects, adjusting for TEAM-specified covariates: fusion type, stratification, year, age, dual eligibility, social disability insurance, grouped total and select Hierarchical Conditions Classification comorbidity, bundled payment participation history, and the Census Division. An expanded model added patient- and hospital-level factors. Variation was quantified using hospital variance, intraclass correlation coefficients (ICC), and Coefficient of Variation (CV).
RESULTS
TEAM participant and non-participant hospitals had similar 30-day readmission rates for inpatient (8.9%; OR 1.01; 95%CI 0.97-1.06; p=0.517) and outpatient (5.7%; OR 0.87; 95%CI 0.75-1.00; p=0.049) fusions, with comparable inpatient (28.2%; OR 0.97; 95%CI 0.92-1.03; p=0.367) and outpatient (10.4%; OR 0.97; 95%CI 0.86-1.10; p=0.645) composite complication rates. For readmission the hospital-level ICC was 1.06%, with TEAM adjusters explaining 61.6% of hospital variance, and reducing the CV from 27.6% to 17.1%. The composite complications, the ICC was 3.61%, with TEAM adjusters explaining 36.6% of variance, reducing the CV from 31.6% to 25.2%. Expanded covariates provided minimal incremental variance explanation.
CONCLUSION
Postoperative complication rates were similar between TEAM participant and non-participant hospitals, and additional adjustments for surgical invasiveness, socioeconomic, patient, and hospital factors did not alter this finding. Between-hospital variance was small relative to case-level variance (∼94%), indicating complications are driven more by patient-level than institutional factors. Although TEAM adjusters substantially reduced the hospital variance, persistent wide variation in readmission and complication rates suggest a considerable quality gap remains.