Fatty infiltration of the cervical extensor musculature, cervical sagittal balance, and clinical outcomes: An analysis of operative adult cervical deformity patients.

PURPOSE: To assess preliminary associations between fatty-infiltration (FI) of cervical spine extensor musculature, cervical sagittal balance, and clinical outcomes in cervical deformity (CD) patients. METHODS: Operative CD patients (C2-C7 Cobb > 10°, CL > 10°, cSVA > 4 cm, or CBVA > 25°) with pre-operative (BL) MRIs and 1-year (1Y) post-operative MRIs or CTs were assessed for fatty-infiltration of cervical extensor musculature, using dedicated imaging software at each C2-C7 intervertebral level and the apex of deformity (apex). FI was gauged as a ratio of fat-free-muscle-cross-sectional-area (FCSA) over total-muscle-CSA (TCSA), with lower ratio values indicating greater FI. BL-1Y associations between FI, sagittal alignment, and clinical outcomes were assessed using appropriate parametric and non-parametric tests. RESULTS: 22 patients were included (Age 59.22, 71.4%F, BMI 29.2, CCI:0.75, Frailty: 0.43). BL deformity presentation: TS-CL: 29.0°, C2-C7 Sagittal Cobb:-1.6°, cSVA:30.4 mm. No correlations were observed between BL fatty-infiltration, sagittal alignment, frailty, or clinical outcomes (p > 0.05). Following surgical correction, C2-C7 (BL: 0.59 vs 1Y:0.67, p = 0.005) and apex (BL: 0.59 vs. 1Y: 0.66, p = 0.33) fatty-infiltration decreased. Achievement of lordotic curvature correlated with C2-C7 fatty infiltration reduction (Rs: 0.495, p < 0.05), and patients with residual postoperative TS-CL and cSVA malalignment were associated with greater apex fatty-infiltration (Rs: -0.565, -0.561; p < 0.05). C2-C7 FI improvement was associated with NRS back pain reduction (Rs: -0.630, p < 0.05), and greater apex fatty-infiltration at BL was associated with minor perioperative complication occurrence (Rs: 0.551, p = 0.014). CONCLUSIONS: Deformity correction and sagittal balance appear to influence the reestablishment of cervical muscle tone from C2-C7 and reduction of back pain for severely frail CD patients. This analysis helps to understand cervical extensor musculature's role amongst CD patients.

Duke Scholars

Author Peter Passias Orthopaedic Surgery

Author Christopher Ignatius Shaffrey Orthopaedic Surgery