No Difference in Reoperation Rates for Adjacent Segment Disease (Operative Adjacent Segment Disease) in Posterior Cervical Fusions Stopping at C7 Versus T1/T2

Abstract

Study Design. A retrospective cohort study with chart review. Objective. To determine whether there is a difference in reoperation rates for adjacent segment disease ([ASD] operative ASD) in posterior cervical fusions (PCFs) that stop at -C7 versus -T1/T2. Summary of Background Data. There are surgical treatment challenges to the anatomical complexities of the cervicothoracic junction. Current posterior cervical spine surgery is based on the belief that ASD occurs if fusions are stopped at C7 although there is varying evidence to support this assumption. Methods. Patients were followed until validated reoperations for ASD, membership termination, death, or March 31, 2020. Descriptive statistics and 5-year crude incidence rates and 95% confidence intervals for operative ASD for PCF ending at -C7 or -T1/T2 were reported. Time-dependent crude and adjusted multivariable Cox-Proportional Hazards models were used to evaluate operative ASD rates with adjustment for covariates or risk change estimates more than 10%. Results. We identified 875 patients with PCFs (beginning at C3 or C4 or C5 or C6) stopping at either -C7 (n ¼ 470) or -T1/T2 (n ¼ 405) with average follow-up time of 4.6 (AE3.3) years and average time to operative ASD of 2.7 (AE2.8) years. Crude overall incidence rates for stopping at -C7 (2.12% [1.02%-3.86%]) and -T1/T2 (2.48% [1.25%-4.40%]) were comparable with no statistical difference in risk (adjusted hazard ratio ¼ 1.47, 95% confidence interval ¼ 0.61-3.53, P ¼ 0.39). In addition, we observed no differences in the probability of operative ASD in competing risk time-dependent models (Grey test P ¼ 0.448). Conclusion.A large cohort of 875 patients with PCFs stopping at -C7 or -T1/T2 with an average follow-up of more than 4 years found no statistical difference in reoperation rates for ASD (operative ASD).

Biomechanical Analysis of Multilevel Posterior Cervical Spinal Fusion Constructs

“…Prior clinical studies have shown conflicting results when comparing the extent of multilevel PCF constructs 4–7,16–20. Osterhoff et al5 showed no difference in radiographic outcomes in a retrospective analysis comparing posterior constructs ending at C7 versus T1 and T2.…”

“…Controversy remains regarding how caudal to extend a multilevel PCF construct. From a clinical perspective, conflicting outcomes have been reported between multilevel constructs ending at C7 and those crossing the cervicothoracic junction 4–7,16–20. A retrospective review demonstrated constructs ending at C7 are over 2 times more likely to require a revision than constructs ending at T1 at a mean follow-up of over 4 years 4.…”

What’s New in Spine Surgery

“…Patients who underwent fusions into the thoracic spine did have more blood loss and longer operative time. Similarly, in a retrospective cohort study with a 4-year follow-up, Guppy et al did not identify a difference in reoperation rates for adjacent segment disease 4 or pseudarthrosis 5 when cervical fusions were stopped at C7 or T1/T2. In the absence of extenuating factors, stopping at C7 may be a reasonable option given the lower morbidity and complication rate, although further work is needed in this area.…”

Crossing the Cervicothoracic Junction

“…They also reported significantly higher rates of wound dehiscence and infection when crossing the CTJ. Similarly, Guppy, et al 56 recently performed a retrospective review of patients undergoing posterior cervical fusion to determine if there was a difference in reoperation rates for ASD when ending constructs at C7 versus T1/T2. They report no difference in operative ASD when stopping at C7 versus T1/T2 in a cohort of 875 patients.…”