骨折椎垂直应力螺钉在胸腰椎骨折中的应用

Fixing the vertical stress pedicle screws into the injured vertebra for thoracolumbar fractures

目的探讨在骨折椎上应用垂直应力螺钉以加强胸腰椎骨折后路内固定的方法和效果。方法回顾性研究2002年3月至2005年3月收治的胸腰椎单一椎体骨折病例,其中16例采用骨折椎加用垂直应力螺钉固定(A组),17例采用传统双平面固定(B组)。A组,男11例,女5例,平均年龄48岁(32～74岁);B组,男12例,女5例,平均年龄40岁(21～61岁)。所有患者外伤均不超过3周,骨折椎一侧或双侧椎弓根完整,椎体下半部及下终板无爆裂。A组在施行后路常规撑开和恢复腰椎前凸的同时,在骨折椎上应用椎弓根螺钉向垂直于撑开应力方向的腹侧加压,以达到局部的应力平衡。术后随访6个月～2年,平均11个月。结果垂直应力螺钉使骨折椎向腹侧移动复位,术后Cobb角及前柱高度恢复较佳。手术前后骨折椎前移复位程度的变化,A组(0.094±0.062)显著高于B组(0.018±0.037),差异有统计学意义(P<0.001);两组Cobb角的变化(A组11.75°±8.73°,B组6.53°±5.03°)及头侧椎体前上缘至尾侧椎体前下缘距离的变化(A组0.484±0.259,B组0.330±0.149),差异也有统计学意义(P<0.05)。骨折椎加用垂直应力螺钉在前柱撑开的同时可有效控制正常椎间盘高度的撑开。结论对胸腰椎单一椎体骨折有条件地应用骨折椎椎弓根螺钉可以增强胸腰椎骨折后路短节段内固定系统的牢固性,并有利于矫正后凸畸形和维持矫正效果。

Objective To explore the technique outcome of fixing the ventral stress pedicle screws into the injured vertebrae, as a method to enhance the posterior internal fixation. Methods From March 2002 to March 2005, 33 single thoracolumbar fractures were studied retrospectively. Among which, 16 cases were treated with the above method （group A）, and the other 17 were treated with traditional two-level fixation（group B）. Group A involved 11 males and 5 females, aged 48 years averagely （range, 32-74 years）; and group B included 12 males and 5 females, aged from 21 to 61 years（mean, 40 years）. All the patients underwent the operation within up to 3 weeks after fracture. For the injured vertebral bodies, their pedicles were intact on either unilateral or bilateral side, and their lower half and endplate were free from split. In group A, the pedicle screws in the injured vertebrae were used to achieve the ventral press vertical to the distraction for the stress neutralization, and also with the routine distraction and lordosis restoration, simultaneously. The mean follow-up period was 11 months with a range from 6 to 24 months. Results After operation, the optimal Cobb angle and anterior column restoration were achieved through the ventral reduction from the injured vertebral body, which was the contribution from the vertical stress pedicle screw. The degree in anterior movement of injured vertebrae pre- and postoperatively was much more in group A than group B, and the difference was of statistical significance （P〈0.001）, and the changes of Cobb angle as well as distance between the anterior-upper edge of the cephalad vertebrae to the anterior-lower edge of the caudal vertebral body was also significant in statistics （P〈0.05）. And the over-distraction of the contiguous discs was also avoided efficiently. Conclusion It can enhance the stiffness of the posterior short-segment instrumentation in single thoracolumbar fractures through fixing the pedicle screws into injured vertebrae selectively, which still can help to correct the kyphosis and maintain the reduction.