A Comparison of Three Different Positioning Techniques on Surgical Corrections and Post-operative Alignment in Cervical Spinal Deformity (CD) Surgery.

STUDY DESIGN Retrospective review of a prospective multicenter cervical deformity database OBJECTIVE.: To examine the differences in sagittal alignment correction between three positioning methods in cervical spinal deformity surgery (CD). SUMMARY OF BACKGROUND DATA Surgical correction for CD is technically demanding and various techniques are utilized to achieve sagittal alignment objectives. The effect of different patient positioning techniques on sagittal alignment correction following CD remains unknown. METHODS Patients with sagittal deformity who underwent a posterior approach (with and without anterior approach) with an upper instrumented vertebra of C6 or above. Patients with Grade 5, 6 or 7 osteotomies were excluded. Positioning groups were Mayfield skull clamp, bivector traction, and halo ring. Pre-operative lower surgical sagittal curve (C2-C7), C2-C7 sagittal vertical axis (cSVA), cervical scoliosis, T1 slope minus cervical lordosis (TS-CL), T1 Slope (T1S), chin-brow vertebral angle (CBVA), C2-T3 curve, and C2-T3 SVA was assessed and compared to post-operative radiographs. Segmental changes were analyzed using the Fergusson method. RESULTS 80 patients (58% female) with a mean age was 60.6 ± 10.5 years (range 31-83) were included. The mean post-operative C2-C7 lordosis was 7.8°±14 and C2-C7 SVA was 34.1mm ± 15. There were overall significant changes in cervical alignment across the entire cohort, with improvements in T1 slope (p   0.05). The majority of segmental lordotic correction was achieved at C4-5-6 (Mean 6.9°±11). Additionally, patients who had bivector traction applied had had significantly more segmental correction at C7-T1-T2 compared to Mayfield and halo traction (4.2° vs. 0.3° vs. -1.7° respectively, p < 0.027). CONCLUSION Post-operative cervical sagittal correction or alignment was not affected by patient position. The majority of segmental correction occurred at C4-5-6 across all positioning methods, while bivector traction had the largest corrective ability at the cervicothoracic junction. LEVEL OF EVIDENCE 4.