先天性颅底凹陷伴寰枢椎脱位患者的手术疗效与影响因素分析

An analysis of surgical outcome and influencing factors in patients of congenital basilar invagination with atlantal-axial dislocation： report of 120 cases

目的探讨先天性颅底凹陷合并寰枢椎脱位患者的手术疗效及影响因素。方法回顾性分析2004年5月至2010年8月因先天性颅底凹陷合并寰枢椎脱位行手术治疗的120例患者资料，采用问卷调查、电话和门诊复查进行随访，93例获得有效随访。患者均采用单纯后路术中直接撑开复位椎弓根螺钉内固定技术治疗。所有患者行术前、术后X线、CT扫描及三维重建、MRI检查。通过比较术前、术后日本骨科协会（JOA）评分、齿状突尖距Chamberlain线的垂直距离（CL）和寰齿间距（ADI），评判患者疗效。所得数据结果采用配对t检验和Pearson相关分析。结果93例患者的随访时间为24～99个月，平均46．5个月。末次随访时，79例（84．9％）症状好转，7例（7．5％）症状稳定、4例（4．3％）加重，3例（3．2％）术后死亡。没有脊髓髓内信号改变的患者，术后恢复最好；同时受到前方齿状突和后方枕骨大孔-寰椎后缘压迫的患者，恢复效果最差（F=3．987，P〈0．01）。术后影像显示87例患者（93．5％）植骨融合良好，减压充分。手术死亡3例分别死于后颅窝血肿、基底动脉血栓和不明原因各1例。结论单纯后路术中直接撑开复位螺钉内固定技术是一项简单、有效和安全的技术；齿状突脱位引起的前方压迫和后方枕骨大孔后缘一寰椎后弓的压迫是造成脊髓损伤的重要机制；脊髓髓内信号的改变常常提示脊髓功能恢复不良。

Objective To investigate the surgical outcome and its influencing factors in patients of congenital basilar invagination （BI） with atlanto-axial dislocation （AAD）. Methods From May 2004 to August 2010, 120 patients who had BI with AAD were surgically treated with direct posterior intraoperafive distraction-reduction and fixation technique, 93 patients were successfully followed up by means of questionnaire survey, telephone and clinical evaluation. Preand postoperative dynamic cervical X-rays, computed tomographic scans, 3-dimentional reconstruction views and magnetic resonance imaging were performed. Preand postoperative Japanese Orthopaedic Association（JOA） score, distance between odontoid tip and Chamberlain＇s line and atlantodental interval were measured to evaluate the surgical result. Statistical analysis was performed by means of paired t test and Pearson Correlation analysis. Results There were 93 cases were followed up for 24-99 months with an average of 46. 5 months. Until the final follow-up, clinical symptoms were improved in 79 patients （ 84. 9% ）, and were stable in 7 patients （ 7.5% ） and deteriorated in 4 patients （ 4. 3% ） . Three patients died postoperatively （ 3.2% ） . Patients without intramedullary signal intensity change （ISIC）had better surgical outcome. Patients with compression from anterior odontoid tip and posterior bone margin of occipital foramen had the worst surgical outcome （ F = 3. 987,P 〈 O. 01 ）. Overall, good decompression and bone fusion were shown on postoperative image in 87 patients （93.5%）. There were 3 deaths in this series because of basilar arte, thrombosis, posterior fossa hematoma and unknown reasons each. Conclusions The direct posterior intraoperative distractionreduction and fixation technique is an effective simple and safe method for the treatment of BI with AAD.Anterior compression from odontoid tip and posterior compression from bone margin of occipital foramenatlantal posterior arch play important roles in its developing mechanism. ISIC on MRI is a predictive factor for the worse surgical outcome.