Cross-sectional area of the longus colli and cervical degenerative spondylolisthesis: A retrospective review evaluating this anatomic consideration

Background: Limited literature is available to define the impact of the longus colli muscle, a deep flexor of the spine, on cervical spine stability despite its close proximity to the vertebrae. Aims and Objectives: The purpose of this study was to determine if longus colli cross-sectional area (CSA) is associated with the severity preoperative cervical degenerative spondylolisthesis. Materials and Methods: Patients undergoing elective anterior cervical discectomy and fusion (ACDF) for cervical spondylolisthesis between 2010-2021 were retrospectively identified. Longus colli cross-sectional areas (CSA) were measured from preoperative MRI images at the C5 level. Preoperative spondylolisthesis measurements were recorded with cervical radiographs. Patients were grouped by quartiles respectively according to longus colli CSAs. Statistical tests compared patient demographics, surgical characteristics, and surgical outcomes between groups. Multiple linear regression analysis was utilized to assess if longus colli CSA predicted cervical spondylolisthesis. Results: A total of 157 patients met inclusion criteria. Group 1 (first quartile) was the oldest (60.4 ± 12.0 years, P = 0.024) and was predominantly female (59.0%, P = 0.001). Group 1 also had the highest maximum spondylolisthesis (0.19 mm, P = 0.031) and highest proportion of grade 2 spondylolisthesis (23.1%, P = 0.003). On regression analysis, lowest quartile of longus colli CSA was an independent predictor of larger measured maximum spondylolisthesis (β: 0.04, P = 0.012). Conclusion: Smaller longus colli CSA is independently associated with a higher grade and degree of preoperative cervical spondylolisthesis, but this finding does not result in adverse postsurgical outcomes.