[The facial nerve and the retrosigmoid approach].

The author gives an account of his experience with the retrosigmoid approach, and emphasizes the preservation of the facial nerve and hearing. A detailed description of the operative technique is given. This approach is used when it is intended to conserve the hearing. The series consists of 2 stage III cases and 26 stage I and II cases. The two stage III cases had total deafness. For the other stages, 25 patients had normal facial function postoperatively. The hearing was preserved in 9 cases in the frequency range 500-1000-2000 Hz, with thresholds of less than 30 dB, and in 7 of cases these criteria were also true for the 4000 Hz frequency. The author feels that the retrosigmoid approach with facial nerve monitoring provides the same degree of safety for the facial nerve as the translabyrinthine approach for surgery of stage I and II tumours.