The effect of C7-T1 fusion on clinical and patient-reported outcomes in ACDF patients: A quality outcomes database study

Background: The C7-T1 segment poses challenges in spinal surgery due to its biomechanical transition from the mobile cervical spine to the rigid thoracic spine, with concerns about subsidence from stress-shielding of the T1 superior endplate by the first rib. The impact of fusing C7-T1 on outcomes remains unclear relative to other levels during anterior cervical discectomy and fusion (ACDF). Objective: In a cohort of patients undergoing ACDF, we sought to determine the impact of C7-T1 fusion on patient-reported outcome measures (PROMs) and clinical outcomes. Methods: A retrospective cohort study using the Quality Outcome Database was conducted for patients who underwent primary single- or 2-level ACDF. The primary exposure variable was fusion of C7-T1. The primary outcome was 3-month and 12-month PROMs, including numeric rating scale for neck and arm pain, neck disability index, quality-adjusted life year (QALY) score, and patient satisfaction. Secondary outcomes included 30-day complications and 3-month readmissions and reoperations. Multivariable regression models were fitted for each outcome, controlling for baseline variables. Results: Of 12,240 patients (age 55.8 ± 11.6 years; 48.7% male) undergoing ACDF, 4736 (38.7%) had C7-T1 fusion. On multivariable regression, fusion of C7-T1 was associated with a greater 3-month QALY score (odds ratio [OR] = 1.142; 95% confidence interval [CI]: 1.055–1.237; p < 0.001) and lower rate of readmission (OR = 0.760; 95% CI: 0.625–0.924; p = 0.006), with no association to other PROMs, patient satisfaction, complications, and reoperation ( p > 0.05). On subanalysis of 4103 myelopathic patients, C7-T1 fusion was only associated with lower odds of 3-month readmission (OR = 0.602; 95% CI: 0.420–0.864; p = 0.006). Conclusion: C7–T1 fusion was associated with a better 3-month QALY score and a lower rate of readmission. Myelopathy patients with C7-T1 fusion were also less likely to be readmitted within 3 months of surgery. C7-T1 fusion was not associated with any other outcome. Our results suggest comparable outcomes when fusing C7-T1, which may be useful when counseling patients facing surgery for pathology at this level.