颅底凹陷症的分型及外科治疗

 目的通过对颅底凹陷症患者的临床和影像学资料进行回顾性分析,提出新的分型及其在外科治疗中的指导意义。方法自2000年7月至2013年6月共收治颅底凹陷症患者34例,男17例,女17例;年龄7~59岁,平均34.5岁。记录其临床症状和体征,摄颈椎正、侧位及动力位X线片并行MR和CT检查。其中合并环枕融合21例, C_2,3融合16例,寰枢椎脱位24例。根据是否合并寰枢椎脱位,将颅底凹陷症分为Ⅰ型（脱位型）24例和Ⅱ型（非脱位型）10例。Ⅰ型根据牵引后是否可以复位分为A、B二个亚型。Ⅰ型通过牵引或前、后路寰枢关节间松解复位;Ⅱ型则采取前路或前、后路枕大孔周围减压,复位减压后行后路固定融合。术后及随访时通过X线片、MRI或CT观察减压、固定及植骨融合情况,手术前后及末次随访时神经功能按日本骨科协会（ Japanese Orthopaedic Association Scores,JOA）评分和Ranawat分级进行评定。结果手术时间130~250 min,平均210 min。出血量150~650 ml,平均240 ml。除2例死亡外,32例获得随访,随访时间11~37个月,平均17.4个月。术前JOA评分4~12分,平均8.4分,术后JOA评分为9~17分,平均14.6分,改善率为71.1%,优良率为72.4%。术前Ranawat分级Ⅱ级11例、ⅢA17例、ⅢB 6例,术后Ⅰ级20例、Ⅱ级11例、ⅢA 1例。植骨于术后7~18个月融合,平均10.5个月。围手术期并发症9例,包括感染3例,脑脊液漏2例,呼吸功能障碍2例,椎动脉损伤、颚裂各1例。结论根据临床和影像学结果将颅底凹陷症分为Ⅰ型（A、B）和Ⅱ型能够有效的指导治疗,术前认真评估、术中仔细操作及减少围手术期各种并发症是保证手术成功、提高疗效的关键。

Classification and surgical treatment of basilar invagination

ObjectiveTo present a new classification of basilar invagination (BI) and evaluate guiding use and effect of the classification for the treatment of BI. MethodsConsecutive 34 patients with BI were surgically treated in our department from July 2000 to June 2013. There were 17 males and 17 females, aged from 7 to 59 years (mean, 34.5 years). The clinical symptoms and signs were recorded, and preoperative imaging examination including anteroposterior, lateral, dynamic X-rays, MRI, CT and 3-dimensional reconstruction views of cervical spine were performed to identify the series. 34 patients with BI were associated with anomalies including atlantooccipital assimilation in 21 cases, C_2-3 fusion in 16 cases, and atlantoaxial dislocation in 24 cases. According to with or without atlantoaxial dislocation, BI was classified into Type I with dislocation in 24 cases and Type II without dislocation in 10 cases. Type I was divided into reducible subtype A in 6 cases and irreducible subtype B in 15 cases under the condition of skull traction. Type I was performed with reduction by traction or release between C_1-2 through anterior or posterior approach, while Type II with decompression by resection abnormal structures through anterior or anteroposterior approach. All patients were underwent posterior instrumentation and fusion. The postoperative X-rays, MRI or CT was taken to observed the results of decompression, fixation and fusion. Neurological function was assessed by JOA scale and Ranawat''s score. ResultsThe average operation time was 210 min, and blood loss was 240 ml. Except for 2 death cases, 32 cases were followed up, and the followed-up was ranged from 11 to 37 months (mean, 17.4 months). JOA scores increased from 8.4 to 14.6 with 71.1% of recovery. The excellent and good rate was 72.4%. According to Ranawat''s score, preoperative score was class II in 11 cases,class IIIA in 17 cases and class IIIB in 6 cases, while postoperative score was class I in 20 cases, class II in 11 cases and class IIIA in 1 case. The perioperative complications was present in 9 cases, including infection in 3 cases, cerebrospinal fluid (CSF) leakage in 2 cases, respiratory dysfunction in 2 cases, vertebral artery injury and cleft palate in 1 case. ConclusionThe new classification of BI can effectively guide and schedule the treatment. Careful evaluation, operation and prevention of perioperative complications are important to ensure the success of surgery.