单侧枕下乙状窦后入路磨开内耳道后壁与骨迷路保护

目的　为枕下乙状窦后入路安全磨开内耳道后壁提供解剖参数。方法　应用１０ 例甲醛固定的汉族成人头颅湿性标本， 以内耳道为中心进行了 Ｃ Ｔ 断层薄扫， 在手术显微镜下磨开内耳道后壁， 保护骨迷路， 用游标卡尺、量规进行了测量。结果　 （１） Ｃ Ｔ 断层薄扫可较好地显示骨迷路与内耳道后壁的关系及岩锥气化程度， 高颈静脉球现象； （２） 在小脑最大牵开程度不大于６１°情况下，不伤及骨迷路， 平均最大磨开内耳道后壁接近总长的２／３ ， 有５ 侧标本低于内耳道总长的５０ ％ ； （３）内耳道后外侧唇与前庭、半规管总脚的距离， 及后垂直半规管与岩锥后表面的距离， 个体变异较大。结论　从该对比研究， 测量 Ｃ Ｔ 断层扫描、磨开内耳道确定前庭、半规管总脚与内耳道后外侧唇的距离， 对比变异不大， 所以术前 Ｃ Ｔ 内耳道断层可以指导术中安全磨开内耳道后壁。

Suboccipital retrosigmoid approach drilling of the posterior wall of the internal acoustic meatus and preserving bone labyrinths of

Objective To supply suboccipital retrosigmoid approach drilling of the posterior wall of the internal acoustic meatus and preserving bone labyrinths. Methods Ten cadaveric adult heads were examined by internal acoustic meatus centered CT thin tomographic scan. Results (1)CT thin tomographic scan can show relations between the posterior wall of the internal acoustic meatus and bone labyrinths; (2)The posterior wall of the internal acoustic meatus may be drillied off 2/3 of its length, without injury the bone labyrinths, but in 5 specimens,a safety drilling within less than 50% of its length; (3) The posterior wall of the internal acoustic meatus and vestibule, semicircular canal common crus, and posterior semicircular canal with the posterior wall of the petrous pyramid varies with each specimens.Conclutions CT thin tomographic scan may help for a safetly drilling the posterior wall of the internal acoustic meatus