寰枢椎椎弓根钉棒系统内固定治疗牵引复位不稳定型寰枢椎脱位

Atlantoaxial pedicle screw system for treatment of unstable atlantoaxial dislocation post traction

目的探讨寰枢椎椎弓根钉棒系统内固定手术治疗牵引复位不稳定型寰枢椎脱位的手术技巧及临床疗效。方法选择2005年3月-2009年9月收治的寰枢椎脱位患者32例（T01分型为T2型）。其中齿状突骨折19例，新鲜性17例，陈旧性2例；横韧带断裂5例；先天性齿状突发育异常8例。术前日本骨科学会（JOA）评分5～13分，平均8．38分；骨髓有效空间（space available for the cord，SAC）平均9．15mm。32例患者经颅骨牵引复位后，经颈后路行寰枢椎椎弓根钉棒系统内固定术。结果32例患者经颅骨牵引后复位，共置入螺钉128枚，手术时间平均1．5h，出血量平均300ml，未发生椎动脉及脊髓损伤。全部患者获随访，时间12～24个月，临床症状获得不同程度改善。术后SAC平均14．86mm；术后1年JOA评分10—17分，平均14．56分，评分改善率为71．70％。X线、螺旋cT复查螺钉位置良好，无钉棒断裂、变形、松动或寰枢椎再次脱位现象。寰枢椎后方植骨于术后3～6个月获骨性融合，1例未植骨，术后1年取出内固定，寰枢关节旋转功能正常。结论寰枢椎椎弓根钉棒系统内固定技术为寰枢椎提供坚强的三维固定，可直视下置钉，术中复位、融合率高，安全有效，是牵引复位不稳定型寰枢椎脱位的理想治疗方法。

Objective To explore the technique and clinical outcome of the atlantoaxial pediele screw system in the treatment of the unstable atlantoaxial dislocation post traction. Methods The study involved 32 patients with atlantoaxial dislocation （type T2 of TOI classification） admitted from March 2005 to September 2009. There were 17 patients with fresh odontoid fracture and two with old odontoid fracture, five with traumatic disruption of the transverse atlantal ligament and eight with congenital odontold dysplasia. JOA scores of neurological function before operation was at a range of 5-13 （ average 8, 38 ）. The average of space available for the cord （SAC） was 9.15 ram. Before the atlantoaxial pedicle screw system was carried out, the skull traction was performed in all the patients preoperatively. Resuits A total of 128 pediele screws were inserted safely, with mean operation time and perioperative blood loss for 1.5 hours and 300 ml, respectively. No injury to the vertebral artery or spinal cord was ob- served. All the patients were followed up for 12-24 months, which showed that JOA scores one year after operation was increased to 10-17 （average 14.56） , with the improvement rate of 71.70% , and that the SAC was average 14.86 mm. The X-ray and SCT scans verified the proper position of the screws, with no internal fixation failure or atlantoaxial redislocation. After 3-6 months, all the patients except for one patient achieved a solid bone fusion. One year after operation, the one patient with no bone graft fusion was removed of the internal fixation system and obtained satisfactory restoration of the rotational function. Conclusions Atlantoaxial pedicle screw system is an effective method for the treatment of the unstable atlantoaxial dislocation post traction, for it has the advantages of stable three-dimension fixation, direct screw placement, intraoperative reduction and high fusion rate.