Sarcopenia Increases Adjacent Segment Degeneration Risk within 3 Years of Anterior Cervical Discectomy and Fusion.

Abstract

Exploratory retrospective cohort. To determine the impact of sarcopenia on adjacent segment degeneration (ASD) following anterior cervical discectomy and fusion (ACDF). Sarcopenia has been shown to worsen sagittal alignment, reduce patient reported outcomes measures postoperatively, and predict early ASD following lumbar fusion. Retrospective data was collected from 333 adult patients who underwent elective ACDF from 2012-2022. Cases of trauma, central nervous system infection or neoplasm, those with prior cervical spine surgery, or those who additionally underwent posterior cervical surgery were excluded. The primary outcome was radiographic ASD development within 3 years of index surgery. Cross-sectional muscle and vertebral body measurements were recorded at the C4 mid-vertebral body level from the most recent preoperative MRI. Odds ratios were calculated with logistic regression analyses. Sarcopenia was characterized as having combined extensor muscle:vertebral body ratio (EM:VBR) ≥1 SD below gender mean (T-score -1). Of 333 patients undergoing elective ACDF, 77 (23.12%) developed radiographic ASD within 3 years. Sarcopenia was the strongest predictor of early ASD (OR 7.225, 95% CI 3.816, 13.682, P<0.0001), with increased muscle fat infiltration significantly increasing ASD risk. Of 60 sarcopenic patients, 33 (55%) developed ASD within 3 years vs 44 of 273 (16.12%) non-sarcopenic patients (P<0.0001). Female gender, vitamin D deficiency, pre-existing adjacent level degenerative changes, and increased T1 slope (T1S) - cervical lordosis (CL) mismatch also increased ASD risk. The use of anterior plating was associated with decreased ASD risk on bivariate (P=0.0259) but not multivariable analysis. Sarcopenia significantly predicted ASD development within 3 years of ACDF. This information can potentially be used to counsel patients on risk of reoperation and tailor treatments pre- and postoperatively, including physical therapy and correction of vitamin D deficiency.