球形探针技术在椎弓根螺钉置钉术中的应用

Ball tip probe technique for pedicle screw placement

目的通过与传统徒手置钉术的比较，评价一种新的椎弓根螺钉置钉技术，即应用椎弓根球形探针系统置入椎弓根螺钉的准确率。方法自2009年5月至2010年6月，对脊柱侧凸、腰椎滑脱、脊柱骨折等疾病需行颈胸腰椎椎弓根钉内固定的患者，术中应用椎弓根球形探针置入椎弓根螺钉。该探针为医用不锈钢制成，包括一个球端、杆和柄，金属球端的直径分别有1．5、2．5、3．0、3．5mm四种，其中直径1．5mm的探针具有较强的硬度和一定的弹性。球形探针技术要点：按标准椎弓根螺钉进钉点定位，高速磨钻去除皮质骨，将椎弓根球形探针按直径从小到大依次缓慢敲入椎弓根内直至达到椎体前方骨皮质。术后采用CT扫描评价椎弓根螺钉钉道情况。并与采用传统徒手技术的病例资料进行对比。结果采用球形探针技术共置入312枚椎弓根螺钉，传统徒手技术置入276枚。术后CT扫描显示球形探针技术组颈椎、胸椎、腰椎椎弓根螺钉钉道准确率为100％，无一例穿出椎弓根骨皮质。传统徒手技术组准确率为78％，共有61枚螺钉（22％）位置不良，23枚（8．3％）穿透椎弓根内侧骨皮质，38枚（13．7％）穿透外侧骨皮质。两组置钉准确率的差异具有统计学意义。所有患者术中和术后均未出现神经、血管和内脏损伤等并发症。结论．与传统徒手置钉技术相比，椎弓根球形探针置钉技术，可准确地置入椎弓根钉，避免因螺钉误置所导致的术后并发症。

Objective The aim in this study was to evaluate the efficacy of the ball tip probe technique in placing pedicle screws in patients. Methods From May 2009 to June 2010, we used ball tip probe technique in pedicle screw placement in patients with scoliosis, spondylolisthesis, spinal fractures and other diseases. The ball tip probe consisted of a metal shaft with a metal ball-shaped tip whose size included 1.5, 2.5, 3.0, 3.5 mm in diameter. The ball tip probe with a diameter of 1.Smm owned a high rigidity and certain flexibility. Ball tip probe technique： A high speed bur was used to remove cortical bone and create a starting point, and then the ball tip probes is tapped gently by a hammer for making a guide hole through the pedicle into the vertebral body. The accuracy of the pedicle screw placements was evaluated on postoperative axial CT scanning The pedicle screw placements was compared between the the ball tip probe group and conventional freehand technique group. Results Three hundred and twelve screws were evaluated in the ball tip group and 276 in the conventional freehand group. All the screws （100%） were in the desired pedicle in the ball tip group and 215 （78%） in the conventional group. In the conventional group, 23 screws （8.3%） were classified as medial violation; 38 （13.7%） as lateral violation. A significant difference was determined between the 2 groups regarding the pedicle breaches. No vascular, pulmonary, or neurological injuries caused by pedicle screws placement was found in either group. Conclusion This study demonstrates the accuracy and reliability of the ball tip probe technique in pedicle screw placement. This technique can probably reduce the risk of complications of screw misplacements.