Abstract :
Introduction: Retrosigmoid exposure to the cerebellopontine angle (CPA) and petrous apex requires extensive retraction of the cerebellum. A presigmoid exposure has a shorter working distance and more anterolateral exposure. The petrosal approach provides a better exposure to this area with less retraction.
Methods: During January 1993 to March 1996, twenty-one consecutive patients were operated using the petrosal approach. There were 11 men and 10 women. Within the group, there were 14 neoplastic lesions, six vascular lesions, and one hamartomatous lesion. Indications for the surgical approach for lesions in the superior and middle basal posterior cranial fossa are reviewed. Its use for the removal of giant acoustic schwannomas is reviewed.
Results: Meningioma was the most common lesion. The tumor was completely removed in nine of the 14 tumors. Supratentorial extension through the tentorial notch was noted in seven patients. For aneurysms originated from the AICA, vertebrobasilar junction, mid basilar artery, and basilar trunk. The first three were clipped and the other was a giant fusiform aneurysm that was trapped. An AVM was found inoperable due to the intimate involvement of the brain stem. A dural AVF was occluded. Two patients in this series died. The surgical techniques of the petrosal approach and partial labyrinthectomy are reviewed.
Conclusions: Skull base surgical techniques reduce the trauma of access by performing extradural bone resection. The petrosal approach provides exposure of the CPA, petrous apex, anterolateral cerebellum, and brain stem with less retraction than the retrosigmoid approach. Performing a partial labyrinthectomy will improve the surgical view. It can give ample exposure for giant acoustic schwannomas. The petrosal approach offers the neurosurgical/neurotological team an improved view to the CPA, but the preferred route to the CPA will depend on the size and location of the tumor and the experience of the surgeon.
