ABSTRACT
Objective To investigate the surgical techniques of the modified presigmoid trans-partial bony labyrinth approach and the advantages in exposure of the petroclival region and in treat the lesion of this area.Methods By simulate the modified presigmoid trans-partial bony labyrinth approach in 15 adult cadaveric heads with the aid of an operating microscope and record important structures in the petroclival region.Results The petroclival region,the posterior cavernous sinus,Meckel cave,the vertebral-basilar artery,the anterior inferior cerebellar artery,the superior cerebellar artery,ipsilateral Ⅲ-Ⅹ cranial nerve nere fully exposured and contralateral Ⅵ cranial nerve were fully exposured.The range of presigmoid exposure was (19.41 ± 1.58)mm,the exposurein of inferior temporal was (14.18 ± 1.88) nun,the maximum exposure angle of slope center depression was (60.54 ± 6.93) °,the depth of operation was (55.87 ± 4.34) mm.Conclusion The advantages of the modified presigmoid trans-partial bony labyrinth approach can earn enough exposures of deep part of petroclival region and posterior part of cavernous sinus,improved petroclival exposure,multiple axes of visualization,preservation of hearing and facial nerve function,and early devascularization of the tumor.
ABSTRACT
BACKGROUND AND OBJECTIVES: Pneumolabyrinth, the presence of air in the inner ear is an evidence of a pathological connection between the fluid-filled space of inner ear and the air-filled space of mastoid/middle ear cavity. The aim of this study is to evaluate the clinical characteristics of pneumolabyrinth combined with temporal bone fracture. SUBJECTS AND METHOD: Among 51 patients with temporal bone fracture, those who visited a secondary referral center between January 2005 to March 2008, 6 patients (7 ears, one bilateral case) with pneumolabyrinth were selected for a retrospective review on their medical records and radiologic findings. RESULTS: All six patients were male, and had concomitant otic capsule-violating fracture in the affected side. All pneumolabyrinths were diagnosed in the CT images taken on the date of trauma, and in one case, the pneumolabyrinth disappeared in a follow-up CT which was taken after 5 days. Six affected ears out of 5 patients showed profound sensorineural hearing loss and one patient with down-sloping severe sensorineural hearing loss showed partial recovery of hearing threshold a month later. Vestibular function tests were performed in four cases and vestibular weaknesses were identified in all affected ears. CONCLUSION: Immediate high-resolution CT might improve the detection rate of pneumolabyrinth combined with temporal bone fracture. Otic capsule-disrupting fracture has been considered to be synonymous with irreversibly severe to profound sensorineural hearing loss, but one case showed partial recovery in this study. Follow-up audiometric tests are needed to check the recovery of hearing threshold.