["Optimized" retrolabyrinthine approach. Contribution of endoscopy of the cerebellopontine angle].

Retrolabyrinthic access was described long ago but was often found to narrow and progressively abandoned in favour of the retrosigmoid route. Certain modification in the initial technique, notably in wider dissection of the dura-mater of the sigmoid sinus and sometimes section of the endolymphatic canal provides a larger access to the ponto-cerebellous angle. A rigid 0 degree or 30 degrees endoscope can be introduced. In order to evaluate this method, we examined surgical specimens and subjects operated via retrolabyrinthic access for a neurinoma of the acoustic nerve in an attempt to preserve auditive function or for suspected vessel-nerve conflict. Our findings demonstrated that the retrolabyrinthic route allows direct access to the ponto-cerebellous angle doser to the vascular and nervous structures than the retro-sigmoid route and also provides remarkable endoscopic vision of the angle and its elements. This route is particularly interesting for surgery of acoustic neurinomas when attempting to preserve the auditive functions, for diagnosis and treatment of vessel-nerve conflicts, and to a lesser extent for vestibular neurotomy or for evaluating certain diseases difficult to diagnosis in the posterior cranial fossa.