Pickett B P, Cail W S, Lambert P R
Division of Otology/Neurotology, Walter Reed Army Medical Center, Washington, DC 20307-5001, USA.
Am J Otol. 1995 Nov;16(6):741-50.
Surgical access to the sinus tympani remains a challenge for otologic surgeons. Usually, the retrotympanum is approached through the middle ear in an anterior to posterior direction during chronic ear surgery. Whether this is via a posterior tympanotomy or after canal wall down tympanomastoidectomy, visualization of the most posterior recess of the sinus tympani is often inadequate. The purpose of this investigation is two fold: (1) to describe the highly variable anatomy of the posterior tympanic cavity and (2) to review the retrofacial approach to the sinus tympani. Histologic sections, cadaver dissections, and diagrammatic illustrations are combined with computed tomographic (CT) imaging to provide a three-dimensional understanding of the sinus tympani and adjacent labyrinthine structures. Viewed from the mastoid, the anatomic structures that define the boundaries of the retrofacial approach include the facial nerve and stapedius muscle laterally, the lateral semicircular canal superiorly, the posterior semicircular canal posteromedially, the vestibule anteromedially, and the jugular bulb inferiorly. When the sinus tympani is well developed, saucerization within these boundaries gives wide access into the sinus and round window niche. The authors suggest that preoperative imaging can select patients who are candidates for a retrofacial approach to expose and remove disease in the sinus tympani. Contraindications to this approach include axial CT image measurements showing a contracted space between the posterior semicircular canal and the medial aspect of the facial nerve, lack of posterior expansion of the sinus tympani, and in cases where these measurements are marginal, the presence of a high jugular bulb or anteriorly positioned sigmoid sinus.
对于耳科外科医生而言，经手术进入鼓室窦仍是一项挑战。在慢性耳部手术中，通常经中耳从前向后进入鼓室后部。无论是通过后鼓室切开术还是在开放式鼓室乳突切除术后，鼓室窦最靠后的隐窝往往难以充分显露。本研究的目的有两个：（1）描述鼓室后部高度变异的解剖结构；（2）回顾经面神经后方入路处理鼓室窦。组织学切片、尸体解剖及示意图与计算机断层扫描（CT）成像相结合，以提供对鼓室窦及相邻迷路结构的三维认识。从乳突观察，界定经面神经后方入路边界的解剖结构包括：外侧的面神经和镫骨肌、上方的外半规管、后内侧的后半规管、前内侧的前庭以及下方的颈静脉球。当鼓室窦发育良好时，在这些边界内进行碟形化可提供进入鼓室窦和圆窗龛的宽敞通道。作者建议，术前影像学检查可筛选出适合经面神经后方入路以暴露和清除鼓室窦病变的患者。该入路的禁忌证包括：轴向CT图像测量显示后半规管与面神经内侧缘之间的间隙变窄、鼓室窦无向后扩展，以及在这些测量结果处于临界状态时，存在高位颈静脉球或乙状窦位置靠前的情况。
