乙状窦前入路处理斜坡凹陷区病变的量化研究

目的量化研究乙状窦前入路中每一步岩骨切除及血管神经牵拉完成后获得的斜坡中央凹陷区显露范围及手术自由度。方法对20例头颅标本采用乙状窦前入路，骨切除分4步进行：迷路后骨质切除，上、后半规管切除，切除岩尖并打开Meckel＇s腔游离三叉神经，全切迷路及耳蜗并后移面神经。每一步完成后分别测量斜坡中央凹陷区的显露范围和手术自由度。结果岩尖切除、打开Meckel＇s腔游离三叉神经后，斜坡中央凹陷区显露面积为（190±32）mm^2，占整个入路完成后的95％，与磨除上、后半规管后的显露范围相比差异显著，手术自由度亦显著增加。结论乙状窦前联合部分迷路岩尖切除手术入路能够较好的显露斜坡中央凹陷区。岩尖的切除和打开Meckel＇s腔游离三叉神经是充分显露斜坡中央凹陷区并提供足够手术自由度的关键步骤。

Quantitative analysis of the presigmoid approach to central dival depression

Objective To analyze quantitatively the surgical freedom and exposure to the central clival depression in each step of petrosectomy via the presigmoid approach. Methods The presigmoid combined with transpetrosal approach were performed on 20 formalin-fixed cadaveric heads. Petroseetomy was divided into four steps ： retrolabyrinthine, partial labyrinthectomy, petrous apicectomy including the mobilization of trigenfinal nerve and tanscochlear resection including posterior mobilization of facial nerve. Two parameters were measured after each step was completed ： （1） the exposed area of central clival depression ; （2） the surgical freedom, Results The markedly increase in exposure was derived by performing the petrous apicectomy and the opening Meckel＇s cave, which provided （190±32） mm^2 of exposure. It was 95% of the exposure provided by tanscochlear approach with the posterior mobilization facial nerve. There were significant difference of the surgical freedom and the exposure between the retrolabyrinthine approach and the partial labyrintheetomy petrous apiceetomy approach. Conclusion The partial labyrintheetomy petrous apieectomy approach provides excellent exposure and surgical freedom to the central clival depression, h is of importance to perform the petrous apicectomy and Meckel＇s cave opening.