Conservative (labyrinth-preserving) transpetrosal approach to the clivus and petroclival region ? indications, complications, results and lessons learned
Tumours or vascular lesions of the clivus and juxtaclival region present a unique challenge to neurosurgeons and a variety of techniques, with a wide spectrum of complexity, have been advocated. This report presents the use of a conservative transpetrosal approach which combines partial removal of the postero-lateral petrous bone with preservation of the labyrinth, with particular focus on efficacy and the reduction of complications. Patients and methods. Over 9 years, 52 patients underwent a conservative combined supra-infratentorial, labyrinth-preserving transpetrosal approach. There were 32 women and 20 men; 33 had tumour lesions including 22 patients with a clival or petroclival meningioma. Among the 19 patients with a vascular lesion, 12 patients had a basilar artery trunk aneurysm, including one giant midbasilar aneurysm. 3 Patients had vertebro-basilar junction aneurysms, and 4 patients had a pontine cavernoma. Data on the clinical features, investigations and operative techniques were extracted from the patient’s case records. Outcome was assessed by serial examinations of the patients or by telephone interview with the treating physician, and in survivors graded as excellent, good or poor. Results. 52 patients, 23 patients (44%) had an excellent outcome, in 21 patients (41%) the outcome was good and in 7 patients (13%) the outcome was poor. One patient with a complex fusiform basilar trunk aneurysm, operated upon as an emergency, died in the postoperative period. Total resection was achieved, as demonstrated by follow-up MRI in 20 of 33 patients with a tumour, including 15 of 22 patients with clival or petro-clival meningiomas. All vascular lesions were treated effectively and in 14 patients with a basilar or vertebro-basilar junction aneurysm, clipping of the aneurysm was achieved. In one patient, a giant calcified vertebro-basilar junction aneurysm was resected. New cranial nerve deficits or an accentuation of a pre-existing deficit, occured in 8 patients with a tumour and 4 patients with a vascular lesion. Complications included: temporary conductive hearing deficit in 4 patients, a minor laceration of the sigmoid/transverse sinus in 4 and transient post-operative CSF leakage in 12 patients. Temporary lumbar drainage resulted in sealing of the CSF leak in 8 patients, but in 3 patients a permanent ventriculo-peritoneal shunt had to be implanted. Conclusion. When based on adequate experience in skull base surgery, the combined supra-infratentorial, conservative transpetrosal approach, with preservation of the labyrinth, allows direct and wide exposure of a large variety of tumour and vascular lesions located along the supra- and infratentorial juxta-clival area; little or almost no retraction of neurovascular structures is needed and with adherence to important principles, complications related to the approach can be minimised.