The cumulative rate of hearing preservation for AMP tumors was 45% in our literature review. Hearing preservation was attempted only in P, A, and M groups where rates of serviceable hearing preservation were 82%, 80%, and 66%, respectively. The facial function was preserved in 100% of P and A tumors, 75% of group M tumors, and 53% of AMP tumors. Tumors were classified in four groups according to the modified Desgeorges and Sterkers classification: posterior petrous (P 17 tumors), meatus and internal auditory canal (M 12 tumors), petrous apex without invasion of the internal auditory canal (A 9 tumors), and cerebellopontine angle with invasion of the internal auditory canal (AMP 15 tumors). The authors performed a retrospective chart review of 53 consecutive patients operated on for a posterior petrous bone meningioma in a tertiary referral center and a literature review. An anatomical classification was used to evaluate surgical outcome depending on the relationship of the tumor to the internal auditory meatus. The aim of this review was to focus on tumors located mainly on the posterior surface of the petrous bone and threatening hearing and facial functions. Meningiomas of the posterior fossa represent a heterogeneous group of tumors regarding difficulty of resection and functional outcome. Hearing was preserved at the same preoperative levels in 31% of the cases. In 3 patients we had to change the approach to a translabyrinthine one to achieve total removal of the tumor in all patients. RESULTS: A good exposure of the internal auditory canal was possible in 19 cases. The following parameters were included in our protocol: total removal of the tumor, intraoperative difficulties or complications, immediate postoperative complications, facial score 10 days and 3 months after the surgery, and audiologic evaluation 90 days after the surgery. All patients had unilateral tumors, with 10 of them occurring in the right ear and 12 occurring in the left ear. PATIENTS AND METHODS: The average age was 35 years, and there were 14 females and 8 males. OBJECTIVE: We conducted a prospective analysis of 22 patients with small vestibular schwannoma and useful hearing who were operated on via a transmastoid retrolabyrinthine approach between January 1994 and March 1999. ![]() In a series of 138 children referred to the House Ear Institute for CI, 3 had a very narrow IAC measuring less than 2 mm in diameter, which resulted in the absence of a sense of sound after electric stimulation.2 It is theorized that atresia of the IAC is secondary to the maldevelopment of the vestibulocochlear nerve, but the facial nerve crosses one of its compartments and its function is occasionally undamaged, as occurred in the case reported by Yates et al.1 We report a case in which bilateral dysplasia of IAC is in the presence of normal facial nerve function. This is of major importance in cochlear implantation (CI), which may prove unsuccessful despite the proper insertion of the electrodes because there are no nerve elements to transmit the acoustic impulses generated in the cochlea to the auditory cortex in the brain.2 Agenesis of the IAC is a rare entity. ![]() ![]() Atresia of one or both IAC is rarely encountered as an isolated condition it is frequently associated with other systemic developmental anomalies.1 Technical advances in imaging studies have made it possible to distinguish aplasia of the entire VCN from aplasia or hypoplasia of the cochlear branch alone or in association with stenosis of the IAC and/or congenital malformation of the labyrinth. Vestibulocochlear nerve (VCN) is classically associated with malformations of external, middle, and/or inner ear.
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