Comparison of intra-operative skull fixation techniques on cervical sagittal parameters.

Background: There is limited literature concerning the use of bi-vector traction to a Mayfield following posterior cervical fusion with respect to cervical alignment parameters. The objective of this study was to determine how variability of intra-operative fixation methods for posterior cervical fusion affects post-operative cervical sagittal alignment parameters.

Methods: After institutional review board (IRB) approval, retrospective chart review of a total of 54 patients who underwent posterior cervical fusion from July 2017 to December 2019 was conducted. The patients were divided into two cohorts based on their intra-operative positioning, those who were affixed to a three-point fixation system, and those who were placed in bi-vector traction. Pre- and post-operative cervical alignment parameters were measured.

Results: There was no difference in post-operative sagittal parameters between the two groups. Each group showed a statistically significant difference in T1-slope when comparing pre- and post-operative measurements.

Conclusions: In our study we did not find that any of our techniques including bi-vector traction, static Mayfield positioning, or dynamic Mayfield positioning were very effective in adding lordosis during posterior cervical fusion surgeries. Interestingly, we also found a statistically significant increase in T1 slope and resulting trend towards increased cervical SVA.