Endonasal and Lateral Approaches to Petroclival Meningiomas: Comparison and Early Clinical Outcome

Object: The complex anatomy and difficult exposure of the petroclival region necessitates the development of multiple, usually sophisticated surgical approaches for the treatment of petroclival meningiomas. However, gross total tumor resection is often not feasible without substantial surgical morbidity. With the goal of early clinical improvement, we have employed less invasive surgical approaches to treat petroclival meningioma patients.

Methods: We retrospectively reviewed 32 patients (62.5% female) with petroclival meningiomas who were surgically treated from August 2008 to December 2012. Eleven patients (34.4%) were managed with lateral approaches (extended retrosigmoid approach – ERSA; far lateral approach – FLA; posterior transpetrosal approach – PTA), seventeen (53.1%) with midline approaches (endoscopic endonasal approach - EEA) and 4 (12.5%) with a combination. We present the degree of tumor resection, clinical outcome and complications by approach and in the entire cohort.

Results: In 59.4% of the cases, the tumor was >4cm and 50% had vascular encasement. Gross total tumor resection was achieved in 27.3% of the patients after lateral approaches and in 17.6% after EEA. Tumor size and vascular encasement were the most important limitations of total tumor resection (p = 0.002 and p = 0.009, respectively). The average Karnofsky Score (KS) at presentation was 73.8 and was inversely proportional to tumor size (p = 0.001) and significantly lower in cases with vascular encasement (p = 0.009). The average postoperative KS was improved at 86.7 and was significantly higher in primary tumors (p = 0.005), tumors <4cm (p = 0.006) and tumors without vascular encasement (p = 0.002). Overall function improved significantly during short-term follow-up of 14 months (range 1–42) (p = 0.026). The greatest surgical benefit occurred in patients with primary tumors (p = 0.03), in elderly patients (p = 0.04) and in those with vascular encasement (p = 0.046). The selected surgical approach did not influence the clinical outcome of the patients, suggesting proper selection. Complications included new cranial nerve palsies affecting mainly the abducens nerve (43.8%) which were partial and well tolerated in the majority of patients, while new lower cranial nerves palsies were noticed in only one case (3.1%). New cranial neuropathies were substantially higher in tumors >4cm (p = 0.04). No oculomotor, trochlear, facial, vestibulocochlear nerve or lower nerves injuries were noted following EEA. Other complications included postoperative hydrocephalus (15.6%) which was lower after midline approaches (p = 0.04) and cerebrospinal fluid leak which mainly occurred after EEA (p = 0.17). One patient died in the perioperative period (3.1%) and another died 6 months after EEA following a prolonged course after rupture of a delayed basilar artery pseudoaneurysm.

Conclusion: Less-aggressive cranial base approaches, including appropriately selected traditional retrosigmoid exposures and the recently introduced EEA, are effective alternatives to transpetrosal approaches for the treatment of petroclival meningiomas. With the goal of symptom relief and quality of life improvement rather than total tumor resection, significant early clinical improvement can be achieved while limiting devastating surgical complications.