耳内镜下经耳道下入路人工耳蜗植入术的解剖研究

Anatomical Basis for Endoscopic Cochlear Implantation Via a Transmeatal Approach

目的介绍一种新的耳内镜下经耳道下入路人工耳蜗植入手术方式,探讨各种植入方式的优缺点。方法在3例甲醛固定的成人正常颞骨标本开展新手术方式,并测量相关参数。结果所有标本均在耳内镜下显露圆窗龛,并植入电极,未开放乳突气房和损伤鼓索神经、面神经。圆窗膜外侧缘到鼓索神经出骨性鼓环处距离(a)5.47±0.11mm;圆窗下缘到外耳道下壁6点电极骨槽骨性鼓环端距离(b)5.62±0.43mm;外耳道下壁长度(c)12.63±0.99mm;面神经乳突段到外耳道下壁电极骨槽的最短距离(d)4.65±0.50mm;外耳道上壁长度(e)17.02±1.52mm。结论耳内镜下经耳道下入路人工耳蜗植入术是一种微创、安全、快捷且容易学习的具有可行性的新手术方式,对显微镜下圆窗显露不满意等复杂病例更具有其优势,但其具体效果尚待临床上进一步验证,并且对于其存在的局限性和并发症风险等问题仍需进一步的研究改进。

Objective To describe a new endoscopic technique for cochlear implantation via a ear canal approach, as well as its advantages and disadvantages. Methods Three human temporal bone specimens(6 ears) were used to simulate cochlear implantation and to measure relevant anatomical parameters under a surgical microscope. Results The round window niche was exposed, and implant electrodes implanted without opening the mastoid cells or damaging the chorda tympani nerve or facial nerve, under an endoscope in all cases. The distance was 5.47±0.11 mm between the lateral margin of round window and the junction of the chorda tympani nerve and the tympanic ring; and 5.62±0.43 mm between the inferior margin of round window and the groove for the inferior wall of the external auditory canal. The length of the inferior wall of the external auditory canal was 12.63±0.99 mm. Distance between the mastoid segment of facial nerve and the groove for the inferior wall of the external auditory canal was 4.65±0.50 mm. The length of the upper wall of the external auditory canal was 17.02±1.52 mm. Conclusion Endoscopic transmeatal approach for cochlear implantation is minimally invasive, safe, time saving and easy to learn. Its advantages in complicated cases include easier exposure of the round window, although its efficacy needs further clinical verification. Further research is needed to define its limitations and risk of complications.