胸腰椎骨折内固定术后伤椎椎体中央高度恢复的影像学研究及临床意义

Radiological studies and clinical significance on the middle height of fractured vertebral body for thoracolumbar fractures after posterior short-segment instrumentation

目的：探讨后路经伤椎与跨伤椎椎弓根螺钉内固定对胸腰椎骨折椎体中央高度恢复的影响及其临床意义。方法：回顾性分析我院2011年1月~2012年12月收治的胸腰椎骨折病例67例，其中男36例，女31例，年龄17~52岁，平均37.8±7.5岁。所有患者为T11～L2单椎体骨折（AO分型为A型），且无严重的神经脊髓症状（ASIA分级为D、E级）。均采用后路短节段椎弓根螺钉内固定术式，按固定方式不同分为经伤椎固定组（A组，n=37）、跨伤椎固定组（B组，n=30）。在PACS图像系统上测量X线侧位片伤椎椎体前缘高度（Ha）、椎体中央高度（Hm）、椎体后缘高度（Hp）及后凸Cobb角，计算Ha压缩率、Hm压缩率，比较术前、术后1周、末次随访时Ha压缩率、Hm压缩率及Cobb角，观察术后骨折椎体中央高度恢复的情况。结果：所有患者获得18~40个月的随访，平均随访时间26.5±8.9个月。无论经伤椎固定还是跨伤椎固定，术后Ha压缩率、Hm压缩率及Cobb角均较术前有显著减少（P〈0.05），其中A组患者Hm压缩率术前为（44.8±10.3）%，术后1周时为（31.6±7.1）%，末次随访时为（31.3±6.8）%。B组患者Hm压缩率术前为（38.6±8.3）%，术后1周时为（32.0±8.4）%，末次随访时为（31.7±8.6）%。A、B两组患者术后椎体中央高度均有约30%的压缩残留。结论：经伤椎和跨伤椎椎弓根螺钉内固定治疗胸腰椎骨折均可促进骨折椎体前缘及中央高度的恢复，改善节段后凸角度，但术后伤椎椎体中央高度有明显压缩残留。

Objectives： To analyze the clinical outcome of short-segment pedicle screw fixation on the recovery of the middle height of fractured vertebral body in thoracolumbar fracture. Methods： From January 2011 to December 2012, 67 patients with thoracolumbar type A spinal injuries were treated with short-segment fixation. There were 36 males and 31 females with a mean age of 37.8±7.5 years（range, 17-52 years）. The types were T11-L2 single-segment vertebral fractures（AO type A） without serious neurologic deficits（ASIA type D, E）. All patients were divided into two groups based on different instrumentations, group A（n=37） was treated with fixation via injured vertebra, whereas group B（n=30） skipping injured vertebra. By using the PACS imaging system to measure the anterior（Ha）, middle（Hm） and posterior（Hp） height of fractured vertebral body, and the kyphotic Cobb angle on lateral X-ray films at preoperation, 1 week of postoperation and final follow-up, then the compression ratios of Ha and Hm were calculated to observe the recovery of the middle height of fractured vertebral body. Results： The mean follow-up time was 26.5±8.9 months（range, 18-40 months）. Regardless of fixation type, postoperative compression ratios of Ha or Hm and Cobb angle significantly decreased compared with preoperation（P〈0.05）. At preoperation, 1 week after operation and final follow-up, the compression ratio of Hm was （44.8±10.3）%, （31.6±7.1）% and （31.3±6.8）% respectively in group A, likewise （38.6±8.3）%, （32.0±8.4）% and （31.7±8.6）% respectively in group B. In terms of Hm, there was still 30% loss of height in two groups. Conclusions： Both two fixations can recover the height of fractured vertebral body and kyphosis Cobb angle, but there is obvious loss of height for Hm at postoperation.