No difference in reoperation rates for nonunions (operative nonunions) in posterior cervical fusions stopping at C7 versus T1/2: a cohort of 875 patients

Abstract

OBJECTIVE The challenges of posterior cervical fusions (PCFs) at the cervicothoracic junction (CTJ) are widely known, including the development of adjacent-segment disease by stopping fusions at C7. One solution has been to cross the CTJ (T1/T2) rather than stopping at C7. This approach may have undue consequences, including increased reoperations for symptomatic nonunion (operative nonunion). The authors sought to investigate if there is a difference in operative nonunion in PCFs that stop at C7 versus T1/T2. METHODS A retrospective analysis identified patients from the authors’ spine registry (Kaiser Permanente) who underwent PCFs with caudal fusion levels at C7 and T1/T2. Demographics, diagnoses, operative times, lengths of stay, and reoperations were extracted from the registry. Operative nonunion was adjudicated via chart review. Patients were followed until validated operative nonunion, membership termination, death, or end of study (March 31, 2020). Descriptive statistics and 2-year crude incidence rates and 95% confidence intervals for operative nonunion for PCFs stopping at C7 or T1/T2 were reported. Time-dependent crude and adjusted multivariable Cox proportional hazards models were used to evaluate operative nonunion rates. RESULTS The authors identified 875 patients with PCFs (beginning at C3, C4, C5, or C6) stopping at either C7 (n = 470) or T1/T2 (n = 405) with a mean follow-up time of 4.6 ± 3.3 years and a mean time to operative nonunion of 0.9 ± 0.6 years. There were 17 operative nonunions, and, after adjustment for age at surgery and smoking status, the cumulative incidence rates were similar between constructs stopping at C7 and those that extended to T1/T2 (C7: 1.91% [95% CI 0.88%–3.60%]; T1/T2: 1.98% [95% CI 0.86%–3.85%]). In the crude model and model adjusted for age at surgery and smoking status, no difference in risk for constructs extended to T1/T2 compared to those stopping at C7 was found (adjusted HR 1.09 [95% CI 0.42–2.84], p = 0.86). CONCLUSIONS In one of the largest cohort of patients with PCFs stopping at C7 or T1/T2 with an average follow-up of > 4 years, the authors found no statistically significant difference in reoperation rates for symptomatic nonunion (operative nonunion). This finding shows that there is no added risk of operative nonunion by extending PCFs to T1/T2 or stopping at C7.

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.…”

Is It Necessary to Cross the Cervicothoracic Junction in Posterior Cervical Decompression and Fusion for Multilevel Degenerative Cervical Spine Disease? A Systematic Review and Meta-Analysis

“…The systematic search yielded 1528 articles, of which 553 were duplicates, and 942 were excluded by screening the title and abstract. After a full-text review, 18 studies were considered improper: six for including patients with diagnosis of trauma, infection, or tumour [13,14,[24][25][26][27]; five for non-comparative study (cervical group vs. thoracic group) [9,[28][29][30][31]; three for the absence of necessary outcomes [12,32,33]; three for partly duplicated cohorts [11,34,35]; and one for non-English study [36]. Finally, 15 studies were included in this systematic review and meta-analysis (Figure 1) [37][38][39][40][41][42][43][44][45][46][47][48][49][50][51].…”

“…Therefore, some studies have recommended prophylactic extension of the fusion construct into the upper thoracic spine, crossing the CTJ, to reduce the rate of complications and need for reoperations [9][10][11]. In contrast, some investigators reported that this procedure would further increase surgical invasiveness and disrupt the posterior stabilising structures, which have no benefits in solid fusion [12][13][14].…”

Lateral Mass Screws Versus Pedicle Screws at C7 - Reoperation Rates for Adjacent Segment Disease (Operative ASD) and Nonunions (Operative Nonunions) in Posterior Cervical Fusions

“…11,[21][22][23][24][25][26][27] Recent studies have shown no difference in reoperation rates for adjacent segment disease and for nonunions stopping posterior fusions at C7 versus crossing the cervical thoracic junction. [28][29][30] The corollary to this is: Does the type of screws used at C7 make a difference in outcomes?…”