Anterior versus Posterior Surgery for Single-Level Metastatic Cervical Spinal Tumors : Comparative Analysis of Sagittal Alignment and Kyphotic Progression.
TL;DR
PCSS was associated with slower kyphotic progression and a lower rate of index vertebral collapse, suggesting more durable radiographic stability that warrants confirmation in larger prospective studies.
Abstract
Objective To compare clinical and radiological outcomes of anterior (ACSS) and posterior cervical spine surgery (PCSS) in patients with single-level metastatic cervical spinal tumor (MCST). Methods We retrospectively reviewed 27 patients with single-level MCST treated at a single institution between January 2001 and February 2024, categorized into ACSS (n = 16) and PCSS (n = 11) groups. Clinical outcomes were assessed using the Eastern Cooperative Oncology Group (ECOG) performance status, Nurick scale, and visual analog scale (VAS) for neck pain. Radiological parameters-C2-C7 cervical lordosis, sagittal vertical axis, T1 slope, neck tilt, and segmental Cobb angle (SCA)-were evaluated preoperatively, at 1 month postoperatively, and at final follow-up. Baseline bone quality (adjacent vertebral Hounsfield units), bone-modifying agent use, and adjuvant radiotherapy/systemic therapy were also assessed. Index vertebral collapse was defined as a decrease in SCA exceeding 10° from 1 month postoperatively to final follow-up. Time to kyphotic progression was compared using Kaplan-Meier and Cox proportional hazards analyses. Results Short-term clinical outcomes did not differ between groups, and both groups achieved comparable kyphosis correction at 1 month postoperatively. However, from 1 month to final follow-up, SCA loss was significantly greater in ACSS (-15.6° ± 7.8° vs -5.5° ± 4.5°; p < 0.001), and index vertebral collapse occurred more frequently in ACSS (81.3% vs 18.1%; p = 0.003). Compensatory changes in T1 slope and neck tilt were significantly greater in ACSS, suggesting greater cranio-cervical adaptation. The median time to SCA decrease exceeding 10° was shorter in ACSS (0.4 vs 2.0 years; log-rank p = 0.0018), and multivariate Cox analysis confirmed a significantly lower hazard of kyphotic progression in PCSS. Operative time was shorter in PCSS (199.1 ± 17.6 vs 245.8 ± 22.5 minutes; p < 0.001). Adjacent vertebral bone density and adjuvant therapy were balanced between groups, although all PCSS cases were performed in the recent era. Conclusion While short-term clinical outcomes were comparable, PCSS was associated with slower kyphotic progression and a lower rate of index vertebral collapse, suggesting more durable radiographic stability that warrants confirmation in larger prospective studies.