Stopping at C2 Versus C3/4 in Elective Posterior Cervical Decompression and Fusion: A 5-Year Follow-up Study.

ABSTRACT

STUDY DESIGN: This is a retrospective cohort study. OBJECTIVE: In patients undergoing elective posterior cervical laminectomy and fusion (PCLF) with a minimum of 5-year follow-up, we sought to compare reoperation rates between patients with an upper instrumented vertebra (UIV) of C2 versus C3/4. SUMMARY OF BACKGROUND DATA The long-term outcomes of choosing between C2 versus C3/4 as the UIV in PCLF remain unclear. METHODS: A single-institution, retrospective cohort study from a prospective registry was conducted of patients undergoing elective, degenerative PCLF from December 2010 to June 2018. The primary exposure was UIV of C2 versus C3/4. The primary outcome was reoperation. Multivariable logistic regression controlled for age, smoking, diabetes, and fusion to the thoracic spine. RESULTS: Of the 68 patients who underwent PCLF with 5-year follow-up, 27(39.7%) had a UIV of C2, and 41(60.3%) had a UIV of either C3/4. Groups had similar duration of symptoms (P=0.743), comorbidities (P>0.999), and rates of instrumentation to the thoracic spine (70.4% vs. 53.7%, P=0.210). The C2 group had significantly longer operative time (231.8±65.9 vs. 181.6±44.1 mins, P<0.001) and more fused segments (5.9±1.8 vs. 4.2±0.9, P<0.001). Reoperation rate was lower in the C2 group compared with C3/4 (7.4% vs. 19.5%), though this did not reach statistical significance (P=0.294). Multivariable logistic regression showed increased odds of reoperation for the C3/4 group compared with the C2 group (OR=3.29, 95%CI=0.59-18.11, P=0.170), though statistical significance was not reached. Similarly, the C2 group had a lower rate of instrumentation failure (7.4% vs. 12.2%, P=0.694) and adjacent segment disease/disk herniation (0% vs. 7.3%, P=0.271), though neither trend attained statistical significance. CONCLUSIONS: Patients with a UIV of C2 had less than half the number of reoperations and less adjacent segment disease, though neither trend was statistically significant. Despite a lack of statistical significance, whether a clinically meaningful difference exists between UIV of C2 versus C3/4 should be validated in larger samples with long-term follow-up. LEVEL OF EVIDENCE Level-3.