Surgical procedure "simplified retrosigmoid approach" for C-P angle lesions.

Previously, we reported surgical results of the simplified retrosigmoid approach for vestibular nerve sectioning in the cases with intractable vertigo. Here, we introduce in details surgical procedures of the simplified retrosigmoid (also called "subasterional" here for simplification) approach developed by one of the authors (J.H.L.). This approach is to operate cerebello-pontine (C-P) angle lesions through a small upper lateral window below the transverse-sigmoid junction. The retroauricular 4-5 cm skin incision, triangular craniectomy 2 cm in width, dural opening and closure, special considerations, and reconstruction of the skull defect were outlined. The bony landmarks for triangle craniectomy below asterion were described in detail. The C-P angle was appropriately approached for microvascular decompression, removal of C-P angle tumors, and vestibular nerve resection. This subasterional approach was characterized by short operation time of 1-3 h and less postoperative discomforts compared to the conventional retrosigmoid approach.