gms | German Medical Science

Objective: To describe the retrosigmoid and the Restrosigmoid Intradural Suprameatal Approach (180° reverse Kawase’s Approach) and ist clinical outcome in patients with petrous apex and petroclival mengiomas.

Method: Between March 2005 and November 2013, 29 patients with Petrous Apex and Petroclival Menigioma underwent tumor removal through a “180° reverse Kawase’s Approach” at our Department.

Results: 7 patients were males, 22 females, mean age was 52.7 years (range 36-77 years). ASA score was I in 9 patients (31%), II in 18 patients (62%), and III in 2 patients (7%). CN V and CN VIII deficit were the presenting deficit in 45% and 41% of the cases. 29 patients were operated through a RISA approach: 24 patients underwent surgery in semisitting position (83%), 5 patients in supine Jannetta position (17%). Pure retrosigmoid approach was sufficient in 13 patients (48%), while in 14 patients (48%) partial mastoidectomy was necessary. Mean surgery time was 274 min (range: 116 to 605 minutes). Time of surgery and extent of craniotomy was not significantly related to tumor size and surgical positioning. Peripheral blood Hb loss was 0.6 g/dl on average in 17 patients (range: from 0.2 to 4.7 g/dl). Only 4 patients (14%) received blood products transfusion. Total resection was achieved in 19 patients (66%), subtotal resection in 8 patients (28,%), partial resection in 2 cases. Surgical complications were: postoperative CSF leak in 3 patients (17%), bleeding in the surgical cavity in 2 patients (7%), pneumocephalus in 1 patient (3%) and air embolism in 1 patient operated in semisitting position (3%). Median ICU stay was 2 days. The surgical outcome was Karnofsky's grade >60% in 27 patients (93%). 10 patients did not develop any new neurological deficit after surgery. Most of these new deficits resulted transient and disappeared at 6 months follow-up. The most frequent postoperative deficit was facial palsy (25%), which totally disappeared or improved consistently (by 2 points in the H-B scale) in all cases.

Conclusions: Immediate brainstem decompression, no temporal lobe retraction, less surgical manipulation of lower cranial nerves and vessels due to the surgical corridor created by the tumor itself, make the RISA a rapid, safe and straight-forward approach for these complex skull base lesions. The approach-related morbidity is low. Patients’ selection based on tumor extension is fundamental to obtain an optimal outcome of such approach.