A modified extended middle cranial fossa approach for acoustic tumors (author's transl)

Abstract

A modified extended middle cranial fossa approach for acoustic tumors as well as surgical techniques and surgical results are described in detail. This method is based upon a combination of Morrison and King's translabyrinthine-transtentorial approach and Bochenek's extended approach through the middle cranial fossa. It has the following advantages: 1) operation can be done in the supine position; 2) it is the shortest approach to the cerebellopontine angle; 3) it yields a more favorable operative field and enables easier operative procedure in the internal auditory canal; 4) even large tumors can be excised in one-stage operation; 5) it is easy to identify and preserve the facial nerve, the anterior inferior cerebellar artery, and its loop in the posterior cranial fossa; and 6) tumors can be orthoptically isolated and safely and certainly excised without compressing the cerebellum and brain stem. There were no hospital deaths in 29 patients who were treated by this operative method. Total and radical removal were performed in 21 patients (78%) ; 13 of 19 (68%) large tumor cases (9 total removal and 4 radical removal), 2 (100%) medium-sized tumors, and 6 (100%) small tumors localized in the internal auditory canal. The facial nerve was anatomically preserved in the posterior cranial fossa and the internal auditory canal from 19 (70%) of the 29 cases; 14 (69%) of the 21 cases which received total removal or radical removal, and 8 (62%) of the large tumor 13 cases. Intracranial end to end anastomosis was conducted in 2 of 8 sacrificed facial nerves, and facial-hypoglossal anastomosis was conducted in the remaining 6 cases, one week after the operation. Long-term follow-up of facial nerve function revealed that 26 of the 27 cases were normal or satisfactory. As for postoperative complications, 3 cases of CSF leakage (one of them was surgically occluded, and the rest healed spontaneously), and one case of postoperative hemiparesis were observed. There was no postoperative temporal epilepsy or aphasia. This method, that is, the neurosurgical-otological team approach, is compared with other methods, and advantages and superiorities of this method are emphasized.