aWengen D F, Podvinec M
Hals-Nasen-Ohren-Universitätsklinik, Kantonsspital Basel.
Laryngorhinootologie. 1998 Feb;77(2):70-3.
Temporary removal of the posterior external ear canal wall allows excellent exposure of the middle ear and epitympanum without the negative sequelae of a cavity as can occur after canal-wall down procedures. Safe fixation of the bony canal wall, however, has not always been possible with a risk for prolonged healing and bone necrosis.
A new technique permits rigid internal fixation of the posterior canal wall. A titanium miniplate of 10 holes length commonly used for orbital rim surgery is adapted to the cortical surface of the mastoid just posterior to the external ear canal. Six holes for 1.3 mm screws are drilled into the cortical bone: two screws behind the ear canal, two screws on the temporal line, and two on the mastoid tip. All fixation material is then removed and a mastoidectomy is carried out with preservation of the cortical bone for the screws. The external ear canal skin, which has been incised previously near the fibrous annulus with lateral extensions, is mobilized laterally using a newly designed retroflected microraspatory. This creates a vital skin flap that might be essential to avoid bone necrosis. No other skin incisions are needed in the canal. The posterior bony canal wall is cut using an oscillating saw Osseoscalpel, secured by facial nerve monitoring. After middle ear surgery and tympanoplasty have been completed, the canal wall is repositioned and fastened precisely in its place with rigid internal fixation allowing a secure stabilization.
This new technique has proven to be safe and reliable on the first five patients. There has been no bone necrosis within an observation period of 18 months.
Rigid internal fixation is an alternative technique to safely readapt the posterior auditory canal wall.
临时去除外耳道后壁可使中耳和上鼓室得到良好暴露，且不会出现像外耳道壁下手术可能导致的术腔相关不良后果。然而，骨外耳道壁的安全固定并非总能实现，存在愈合时间延长和骨坏死的风险。
一种新技术实现了外耳道后壁的坚固内固定。将常用于眶缘手术的10孔长度的钛微型钢板适配于外耳道后方乳突的皮质表面。在皮质骨上钻出6个用于1.3毫米螺钉的孔：两个螺钉位于外耳道后方，两个螺钉位于颞线，两个位于乳突尖。然后移除所有固定材料，并在保留螺钉所用皮质骨的情况下进行乳突切除术。先前在纤维环附近切开并向外侧延伸的外耳道皮肤，使用新设计的后翻式微型刮匙向外侧游离。这形成了一个重要的皮瓣，可能对避免骨坏死至关重要。外耳道无需其他皮肤切口。使用摆动锯（骨手术刀）在面神经监测下切开后骨外耳道壁。中耳手术和鼓室成形术完成后，将外耳道壁重新定位并用坚固的内固定精确固定在其位置，实现稳固稳定。
这项新技术在前5例患者中已证明是安全可靠的。在18个月的观察期内未出现骨坏死。
坚固内固定是一种安全重新适配后外耳道壁的替代技术。
