Introduction: Long-segment posterior spinal fusion involving the cervicothoracic junction carries higher complication rates due to its unique anatomy and biomechanical stress as compared with non-junctional regions. To address this issue, the extension of fusions from C7 to the thoracic spine and/or C3 to C2 is oftentimes performed. However, the impact of the caudal extension in conjunction with the rostral extension on clinical outcomes has not yet been well-characterized in the literature.
Methods: Retrospective clinical record review from 2010 to 2015 identified 157 patients undergoing long-segment posterior cervical or cervicothoracic fusion (C3-C7, C3-T2, C2-C7, or C2-T2) for degenerative diseases with a minimum one-year follow-up period. They were sub-classified into the two groups: fusions ending in the cervical spine (Group 1, n=58) and those ending in the thoracic spine (Group 2, n=99). Rates of pseudarthrosis, adjacent segment disease, and overall surgical revision were compared as primary outcome measures. P values < 0.05 were defined as statistically significant.
Results: There were no statistically significant differences in baseline characteristics such as age, BMI, and gender. Group 2 had significantly higher estimated blood loss and longer operative time and hospital stay than those in Group 1 (p<0.05 for each). Rates of all three primary outcomes were comparable between the groups (Table 1). In multivariate analysis (Table 2), the upper-most level (C2 versus C3) was the only independent factor predictive of rates of pseudarthrosis (p=0.003), adjacent segment disease (p=0.019), and reoperation (p=0.016).
Conclusions: The rates of adverse surgical outcomes in long-segment cervical fusions were highly correlated with the upper-most level of the fusion, regardless of its corresponding caudal level extension. Given the higher estimated blood loss and longer operative time and length of hospital stay associated with the caudal extension, preferential selection of the upper-most fusion level at C2 should take precedence over routinely extending into the thoracic spine.
Patient Care: Extending long-segment fusions across the cervicothoracic junction was associated with increases in operative time, blood loss, and hospital stay without appreciable benefit in reducing long-term complications such as pseudarthrosis, adjacent segment disease, and overall surgical revision. The findings from our research may provide us with a caveat against the routine extension of fusions to the thoracic spine. Rather, it was discovered that the proximal segment should be paid more attention to in order for us to improve the long-term outcomes.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of the proximal extension of fusions rather than the distal extension in cervicothoracic junction surgery and 2) Discuss, in small groups, advantages and disadvantages of C7-to-thoracic extension as well as C3-to-C2 extension.