Репозиторий Университета

© 2017 EDIZIONIMINERVAMEDICA. BACKGROUND: Goals of vestibular schwannoma (VS) microsurgery are maximal resection, facial nerve (FN) preservation and in selected cases, hearing preservation (HP). Postoperative HP rates are related to clinical and radiographic factors: Size of tumor, preoperative hearing, hypertension, diabetes, and presence or absence of preoperative tinnitus. In this retrospective review we evaluated the influence of preoperative tinnitus on HP after VS surgery in patients with preoperative socially useful hearing (SUH). METHODS: Twenty-five patients with SUH underwent VS micro neurosurgery by retrosigmoid (RS) approach. Selection criteria were pure tone audiogram ≤50dB loss and speech discrimination score >50% (50/50 criterion, AAO-HNS class A-B). In relation to maximum diameter, we identified two size-groups: 1) group A ≤2cm (13 cases); 2) group B >2cm (12 cases). HP attempt was assisted by intraoperative ABR evoked by LS CE-Chirp® (Interacustics, Middelfart, Denmark) acoustic stimuli. RESULTS: Mean age was 44.3 years (20-64); average maximum diameter 2,0cm (0,8-4). Preoperative tinnitus was present in 10 patients (40%): All of them had a Class B-hearing. Total and nearly-total (>95%) resection was possible in all. Mortality and major morbidity were zero. In all, facial nerve (FN) was anatomically and functionally preserved; in 10 an incomplete FN deficit was followed by complete recovery within 2-8 weeks. At a follow-up ranging from 8 to 17 months (average 12.7 months), socially useful hearing (SUH) preservation rate was 52%, with significant differences in relation to size: 61.5% group A and 41.7% group B (P=0.014). Postoperative AAO-HNS C (serviceable) hearing was observed in 36%, deafness in 12%. At last follow-up, among the 10 patients with preoperative tinnitus 6 worsened from Class-B to Class-C, 3 remained in Class-B, and one was deaf. As regards SUH preservation, 3 of 10 patients with preoperative tinnitus and 10 of 15 without it remained in Class-A-B (P=0.006). CONCLUSIONS: Microsurgery represents the first therapeutic option for small growing VS with SUH. Our data confirm that key-hole RS rea moval of VS with intraoperative LS-CE-Chirp ABR monitoring allows good rate of SUH preservation, especially maximum diameter does not exceed 2cm. Preoperative tinnitus seems to indicate a lower hearing reserve and predicts a lower likelihood of HP.

© 2018 Izdatel'stvo Meditsina. All Rights Reserved. In the review article are considered the recent data that emphasize the role of cortical disturbances in the pathogenesis of vestibular disorders. The vestibular system not only provides a link between motor and sensory processes, its functions are much more extensive. The experiments conducted in recent years on primates, as well as the data obtained by neuroimaging methods, have significantly advanced our understanding of the functioning of the vestibular system, especially its central parts. The vestibular cortex can be considered as a network of connections between all cortical areas receiving sensory input from the vestibular system, including cerebral zones in which vestibular information affects the analysis of other sensory (i.e. somatosensory and visual) and motor activity. The pathogenesis of vertigo and tinnitus is especially analyzed.