中文摘要：

目的 探讨软膜下切除小脑扁桃体联合后颅窝小骨窗减压扩容术治疗合并脊髓空洞症的Chiari-Ⅰ畸形的手术改良方式及疗效。方法 回顾性分析2012年1月至2014年1月采用显微外科技术行软脑膜下小脑扁桃体切除联合小骨窗减压扩容改良术治疗29例合并脊髓空洞症的Chiari-Ⅰ畸形患者的临床资料。手术方法：取俯卧头颈同轴位,术中行后颅窝小骨窗减压,打开寰椎后弓;在保持软脑膜完整的前提下将小脑扁桃体下疝入颈椎管内部分作软膜下切除;行四脑室正中孔处粘连松解;切开的蛛网膜与硬膜缘缝合避免形成医源性死腔;最后用自体筋膜修补减张缝合硬膜,全程控制脑脊液释放速度。结果术后随访24例,失访5例。23例患者术后近期（1年内）疗效评价为有效（有效率95.8%）,术后6个月后复查MRI见延髓和上颈髓后方压迫解除,小脑扁桃体下缘升至枕骨大孔以上平面,下疝解除,脊髓空洞明显缩小或消失。结论 显微神经外科手术改良软脑膜下小脑扁桃体切除联合后颅窝小骨窗减压扩容术是治疗Chiari-Ⅰ畸形并脊髓空洞症的一种有效方法。

英文摘要：

Objective To explore a modified method of cerebellar tonsillectomy combined with posterior fossa decompression via small-size craniotomy for Chiari-Ⅰ malformation associated with syringomyelia and to evaluate its clinical efficacy.Methods The clinical data of 29 Chiari-Ⅰ malformation patients associated with syringomyelia,who underwent modified cerebellar tonsillectomy combined with posterior fossa decompression via small-size craniotomy from January 2012 to January 2014,were analyzed retrospectively.Patients were prone with head and neck in the coaxial position and received surgical intervention including posterior fossa decompression via small-size craniotomy,opening the rear atlas arch,resection of the inner part of cervical canal of the cerebellar tonsil herniation while keeping the integrity of soft meninges,adhesiolysis of median aperture of the fourth ventricle,dissection of the suture of arachnoid and dural edge to avoid latrogenic dead space,and suture of the dura with autologous fascia.The cerebrospinal fluid release rate of the whole process was controlled.Results A total of 24 patients were followed up after operation while 5patients were lost in follow-up.The clinical symptom of 23 patients was improved within one year after operation.The repression of medulla oblongata and posterior upper part of cervical cord was removed in MRI examination 6 months after operation.The lower edge of cerebellar tonsillar was up to the plane above the foramen magnum and the herniation was resolved.The syringomyelia was shortened or disappeared.Conclusion Modified cerebellar tonsillectomy combined with posterior fossa decompression via small-size craniotomy,as a microscopy neurosurgery,is an effective method for the treatment of Chiari-Ⅰ malformation associated with syringomyelia.