Titanium mesh cage subsidence following anterior subtotal vertebrectomy for cervical spondylosis: the underlying mechanism and its effect on cervical neurologic function / 中国组织工程研究

ABSTRACT

BACKGROUND: Anterior subtotal vertebrectomy and fusion using titanium mesh cage (TMC) is an effective surgical treatment for cervical spondylosis, while TMC subsidence usually occurs. The risk factors for TMC subsidence and its effect on the treatment outcomes remain controversial. OBJECTIVE: To investigate the TMC subsidence after anterior subtotal vertebrectomy and TMC fusion and its effect on the treatment outcomes, thereby understanding the underlying mechanism and related risk factors. METHODS: Clinical data of 34 patients undergoing anterior subtotal vertebrectomy and TMC fusion in the Second Department of Spine, Shanghai Changzheng Hospital Affiliated to the Second Military Medical University from March to September 2015 were analyzed retrospectively. After 12-month follow-up, the height of the fused segments was measured, and the neurologic outcomes were evaluated using the Japanese Orthopedic Association scores. The loss of the fused segments subsided more than 3 mm compared with that at 1 day postoperatively was considered as TMC subsidence, and all patients were allotted to TMC subsidence and control (without TMC subsidence) groups.RESULTS AND CONCLUSION: (1) Totally 19 patients (56%) experienced TMC subsidence that occurred in postoperative (6.00±3.73) months averagely. (2) No significant differences were found in the age, sex or the level of fused segments between two groups (P=0.731, 0.672, 0.053). (3) The Japanese Orthopedic Association recovery ratio in the control group was significantly higher than that in the TMC subsidence group (P=0.01), suggesting that TMC subsidence might be correlated with the poor improvement of neurologic function after surgery. (4) To conclude, TMC subsidence is a common complication after anterior subtotal vertebrectomy, which does harm to the treatment outcomes.Moreover, age, sex or the level of fused segments are not independent risk factors for TMC subsidence.