后路全脊椎截骨治疗严重脊柱畸形内固定棒断裂危险因素分析

 目的 探讨严重脊柱畸形后路全脊椎截骨(posterior vertebral column resection， PVCR)术后内固定棒断裂的危险因素及处理策略。方法 回顾性分析2003年6月至2011年6月行PVCR术后发生内固定棒断裂的7例脊柱畸形患者资料，男4例，女3例；初次手术时年龄12~39岁，平均24.4岁。记录发生断棒的时间、位置，分析其断棒原因。结果 7例患者内固定棒断裂时间为术后6~53个月，平均23.4个月；其中5例在术后2年以内，2例在术后4年后。6例(85.7%，6/7)断棒水平与切除椎体水平一致。内固定棒断裂原因：(1)残留后凸(1例)，(2)残留后凸合并步态不稳(1例)，(3)残留后凸合并单棒内固定(1例)，(4)残留后凸合并后期钛网移位(1例)，(5)残留后凸合并前柱缺损(1例)，(6)外伤(2例)。6例患者接受翻修手术，其中一期前后路联合翻修手术5例，单纯后路翻修手术1例；翻修术后随访12~22个月，平均18个月。末次随访时X线片示植骨融合良好，无明显矫正丢失，内固定无松动、断裂。结论 PVCR术后内固定棒断裂多发生于术后2年内，断裂水平多与切除椎体水平一致。残留后凸畸形是断棒的重要因素，外伤、前柱缺损、摇摆步态、单棒内固定、钛网移位等增加了断棒的风险。

Risk factors for rod fracture in patients with severe kyphoscoliosis following posterior vertebral column resection

Objective To investigate the risk factors and revision strategies for rod fracture in patients with severe kyphoscoliosis following posterior vertebral column resection (PVCR). Methods Between June 2003 and June 2011, 7 patients (4 males and 3 females) who developed rod fractures following PVCR in our institution were retrospectively reviewed. The average age was 24.4 years (range, 12-39 years) at the time of primary surgeries. The occurrence times and locations of the rod fractures were recorded and the risk factors for the fractures were analyzed. Results The occurrence times of the rod fractures ranged from 6 to 53 months. Five cases of fracture occurred within 2 years after the primary surgeries, while the other 2 cases occurred more than 4 years after the primary surgeries. Six cases of fracture occurred at levels of osteotomies and 1 case occurred at 1 level below the osteotomy. The potential reasons for rod fractures were listed as follows: (1) residual kyphosis (1 case); (2) residual kyphosis combined with unsteady gait (1 case); (3) residual kyphosis combined with single rod fixation (1 case); (4) residual kyphosis combined with malposition of titanium mesh cage (1 case); (5) residual kyphosis combined with anterior column defect; (6) injury (2 cases). Six patients underwent revision surgeries, 5 patients received one-stage combined anterior-posterior approach surgeries, while 1 patient received single posterior surgery. They were followed up for 12 to 22 months (average, 18 months). At final follow-up, all patients obtained satisfying corrections and graft fusion, without internal fixation-related complications. Conclusion Rod fractures mostly occur at levels of osteotomies within 2 years after PVCR. Residual kyphosis is the main risk factor for the rod fracture. Injury, anterior column defects, unsteady gait, single rod fixation and malposition of titanium mesh cage also increase risks of rod fractures.