Chiari畸形合并脊髓空洞症手术治疗前后颅颈部蛛网膜下腔形态学对比研究

Comparative study of alteration of local subarachnoid space before and after operation of Chiari malformation accompanied by syringomyelia

目的研究手术治疗Chiari畸形合并脊髓空洞症(Chiarimalformation-syringomyelia,CM-SM)前后颅颈交界区蛛网膜下腔的形态学变化,探讨CM-SM的发病机制。方法回顾分析34例手术治疗的CM-SM患者的磁共振(MR)资料。单纯颅后窝减压术(PFD)7例,PFD+硬脑膜成形术(PFDD)27例。随访23例。根据随访的临床症状体征和影像学改变情况,测量小脑扁桃体下疝程度(ECT)、第四脑室底与斜坡延长线的夹角α、颅后窝(PCF)和CCJ及其内SS的容积等形态学指标,与术后对照,分析CM-SM发病机制和疗效。结果术后小脑扁桃体平均上抬10.07 mm,α角平均增大7.95°,PCF和CCJ容积分别平均增加11.29 ml和6.29 ml,整个CCJ区SS容积均较术前平均增加14.44 ml(2.2倍),与术前比较,差异均有统计学意义(P<0.05)。PFD术后有效率为71.4%,PFDD术后有效率为96.3%,两者比较差异有统计学意义(P<0.05)。结论 SS狭窄是CM-SM的主要病因,同时证明了PFDD是治疗CM-SM的一种较有效的手术方式。

Objective To observe the morphological changes of subarachnoid space（SS） at craniocervical junction（CCJ） in patients with type I Chiari malformation（CM I） accompanied by syringomyelia（SM） after the operation,and to study the pathogenesis of CM-SM.Methods The magnetic resonance images（MRI） in 34 CM I patients were reviewed.Twenty-seven patients underwent posterior fossa decompression with duraplasty（PFDD）,and another 7 patients underwent posterior fossa decompression without duraplasty（PFD）,and 23/34 were followed up by MRI.The extent of cerebellar tonsillar hernia（ECT）,the α angle between clivus and the floor of the fourth ventricle,the volumes of the posterior cranial fossa（PCF）,CCJ and SS on the sagital MRI were measured separately.Results Cerebellar tonsils elevated 10.07 mm,α angle increased by 1.95°,the PCF and CCJ volume increased by 11.29 ml and 6.29 ml respectively after procedure.The SS volume in CCJ region increased 14.44 ml（2.2 times that before procedure）.These changes were of statistical difference compared with pre-procedure（P0.05）.The effective rate of PFDD（by a mean of 96.3%） was significant higher than that of PFD（by a mean of 71.4%）（P0.05〉.Conclusions The narrowing of SS plays an important role in the pathogenesis of SM-CM.It is proved that PFDD for the treatment of CM-SM is preferred.