枢椎泪滴样骨折形成机制和手术方案选择

Formation mechanism and surgical choice of teardrop fracture of the axis

目的探讨枢椎泪滴样骨折的形成机制，观察根据骨折分型采取前后路不同的内固定方法的临床疗效。方法选择2001年5月-2010年10月间收治的13例枢椎泪滴样骨折，其中男10例，女3例；年龄18-55岁，平均35．5岁。其中4例合并颈髓损伤[美国脊髓损伤协会（ASIA）C级1例，D级3例]。致伤原因：交通伤11例，坠落伤2例。人院后均行颈椎正侧位、张口位X线片和螺旋CT矢状位重建及MRI检查。根据损伤机制进行临床分型，伸直型10例采用颌下咽后入路行C：．，椎间植骨融合内固定；屈曲型3例采用后路C2.3椎板间植骨融合加椎弓根（或C，侧块）内固定，并对分型后的手术方案进行疗效观察。结果13例手术患者均成功完成暴露和有效复位内固定，前路平均手术时间77min，后路平均手术时间125min，无手术副损伤。患者均获随访，时间9-34个月，平均13个月。术后4个月复查植骨均获骨性愈合。无内固定松动、断裂等并发症。3例ASIAD级患者术后1．5个月、1例ASIAC级患者术后6个月脊髓功能恢复正常。结论根据枢椎泪滴样形成机制为依据制订针对性手术方案，临床疗效确切，安全可行。

Objective To discuss the formation mechanism of teardrop fracture of the axis and observe the clinical efficacy of anterior or posterior induction operation according to the fracture type. Methods Thirteen patients with teardrop fracture of the axis treated from May 2001 to October 2010 were involved in the study. There were 10 males and 3 females, at age range of 18-55 years （mean, 35.5 years）. Four patients were combined with cervical spinal cord injury （one patient with grade C and two with grade D according American Spinal Injury Association, ASIA）. Injury causes included traffic injury in 11 patients and fall from height in two. After admission, the anteroposterior, lateral and mouth X- ray films, spiral CT sagittal reconstruction and MRI examination of the cervical vertebra were performed in all the patients. According to the injury mechanism, there were 10 patients with extension fractures treated with C2,3 intervertebral bone fusion and internal fixation through submandibular retropharyngeal ap- proach and three with flexion fractures treated with posterior C2,z intervertebral bone fusion and pedicle screw fixation. The clinical efficacy was also observed. Results All patients received complete expo- sure and effective reduction and fixation. The average time of anterior exposure and posterior exposure was 77 minutes and 125 minutes, respectively. No surgical complications occurred. All patients were followed up for 9-34 months （mean, 13 months）. Reexamination at four months after operation displayed bone healing in all patients. There was no lessening or breakage of the internal fixators. The spinal function of three patients with ASIA grade D injury and that of one patient with ASIA grade C injury recovered to norreal at postoperative 1.5 and 6 months respectively. Conclusion The surgical approaches for teardrop fracture of the axis developed in the light of the fracture formation mechanism are beneficial and safe.