Microsurgical Treatment and Classification of Petroclival Meningioma: Experiences in 471 Patients at a Single Institute for 18 Years

Background: Although there has been great development in the anatomical understanding and operative techniques for skull base tumors, controversy still exists regarding the optimal surgical strategies for petroclival meningioma (PCM). Different subtypes of PCM cause variation of symptoms and, therefore, surgical approaches. The authors reviewed 471 consecutive cases of PCM operated on between October 1992 and March 2010 in the Division of Skull Base, Department of Neurosurgery at Beijing Tiantan Hospital. Neuroimaging classification of PCM is established before deciding on a surgical plan.

Methods: A total of 471 (327 females and 144 males) consecutive cases of PCM between October 1992 and March 2010 in Beijing Tiantan Hospital were reviewed. The data reviewed included the patients' preoperative symptoms, operation notes, pre-and post-neuroimaging, assessment of quality of life, and neurologic dysfunction.

Results: A six-subtype classification system was established based on tumor origin and extension direction. Petroclival meningiomas were classified as six subgroups including: petrous apex (35 cases), cavernous sinus (40 cases), sphenopetrosal (56 cases), petroclival and cavernous sinus (75 cases), cerebellopontine angle (33 cases), clival (62 cases), and extensive (170 cases). Intracranial nerves palsy (58%) was the most common presenting symptom. The surgical approach was chosen according the classification of the neoplasm. The subtemporal transtentorial approach was performed in 172 cases, presigmoidal approach in 165 cases, retrosigmoidal approach in 46, frontotemporal approach in 40, Kawase's approach in 36, and other approaches in 12 cases. Gross total resection was achieved in 84.0% of patients, and subtotal resection in 16.0%. Surgical mortality was 2%.

Conclusion: Our experience suggests that the classification of six subtypes of PCM is practical and helpful for the preoperative surgical plan. Although the mortality of PCM decreased significantly, the neurological deficits are still a big challenge for microsurgical resection of PCM, particularly for giant PCM.