1/3. Relationship between cochleovestibular disorders in hemifacial spasm and neurovascular compression.OBJECTIVE: To investigate the evolution of cochleovestibular symptoms before, during, and after microvascular decompression (MVD) of the facial nerve in hemifacial spasm. STUDY DESIGN: Prospective study in patients with hemifacial spasm. Among our 13 patients who underwent MVD of the facial nerve from 1995 to 1997, 6 had associated cochleovestibular disorders confirmed by neurotologic tests. RESULTS: In four of these patients, a concomitant compression of the eighth and facial nerves was found at surgery. Preoperative magnetic resonance angiography studies had shown three cases of this double neurovascular compression. Intraoperative auditory brainstem response monitoring showed that interposition of Teflon between vessel and facial nerve was highly critical to the auditory function. Auditory brainstem response monitoring was used to guide the surgeon during this critical phase. Surgery improved at least one cochleovestibular symptom in each patient. CONCLUSIONS: The authors propose two pathophysiologic hypotheses. First, the concomitant facial and cochleo-vestibular symptoms may be due to a hyperactivity of both the facial and vestibular nuclei. According to theories about cryptogenic hemifacial spasm, the origin of this hyperactivity could be an ectopic excitation focus. However, the two nerves may have different sites of ectopic excitation. According to the second hypothesis, a pulsatile compression of the facial nerve may be transmitted to the eighth nerve. This could take place even if only the facial nerve is in contact with a vascular loop.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
2/3. Vascular occlusion in the endolymphatic sac in Meniere's disease.In 2 patients with severe Meniere's disease (MD), there was histologic evidence of occlusion of the vein of the vestibular aqueduct (VVA). This finding coincided with total or partial occlusion of numerous small vessels around the endolymphatic sac (ES), flattening of epithelium, extensive perisaccular fibrosis, and signs of new bone formation. Ultrastructural analysis of the occluding material showed foci with dense connective tissue, calcification, lipid deposits, and layers of basement membrane, sometimes concentrically arranged. The exact nature of the occluding material was unknown. In another 2 MD patients, the VVA was not visualized, and the ES vessels showed no signs of occlusion. Seven controls with acoustic schwannoma or meningioma had normal vasculature. The presence of vascular impairment in the ES in MD patients indicated that altered hemodynamics may contribute to the pathogenesis of endolymphatic hydrops and MD.- - - - - - - - - - ranking = 2keywords = vessel (Clic here for more details about this article) |
3/3. Surgical treatment of endolymphatic sac tumor with adjunctive stereotactic radiation therapy--case report.A 44-year-old man presented with an endolymphatic sac tumor (ELST) associated with von hippel-lindau disease, which required four surgical procedures within 10 years. The earlier two surgeries resulted in only partial removal of the tumor because of vigorous intraoperative bleeding. Stereotactic radiation therapy was performed twice. The intraoperative bleeding was easy to control in the third operation, and ultimately the tumor was totally extirpated in the fourth operation. Histological examination of the tumor specimen harvested in the final surgery showed that the tumor cells had clearly decreased in number, and the interstitial tissue had become fibrous with organization of the tumor vessels, compared with the tumor specimen from the first surgery. Preoperative radiotherapy may be effective to reduce the devastating intraoperative bleeding of ELST.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |