Subsidence of Titanium Mesh Cage

STUDY DESIGN: A cohort study. OBJECTIVE: To clarify the risk factors for the subsidence of the titanium mesh cage (TMC) after anterior cervical corpectomy and fusion, and to discuss their clinical correlations. SUMMARY OF BACKGROUND DATA: Fusion with TMC after anterior cervical corpectomy has become popular as an established treatment for cervical degenerative diseases, but postoperative TMC subsidence has often been reported in the literature. METHODS: A total of 300 patients with anterior cervical corpectomy and TMC fusion were included in the study, including 1-level corpectomy in 236 patients and 2-level corpectomy in 64. TMC subsidence, radiologic findings, and clinical results were evaluated in the 12-month follow-up period. RESULTS: TMC subsidence occurred in 239 (79.7%) cases, including mild subsidence (1 to 3 mm) in 182 (60.7%) and severe subsidence (>3 mm) in 57 (19.0%). Two-level corpectomy was more susceptible to severe subsidence, when compared with 1-level corpectomy (P<0.001). Japanese Orthopedic Association recovery rate for severe subsidence was significantly lower than that for no subsidence (P=0.010). Severe subsidence was correlated with subsidence-related complications, including neck pain, neurologic deterioration, and instrument failure. CONCLUSIONS: TMC subsidence was a common phenomenon after anterior cervical corpectomy and fusion with TMC. Level of corpectomy was a unique risk factor for severe subsidence in this study, which might have led to bad clinical results and subsidence-related complications.