Surgical Management of Petroclival Meningiomas Based on a Radiographic Classification with Updated Follow-up

Background: Surgical management of petroclival meningiomas (PCMs) was challenging accompanied with relatively high morbidity. Treatment selection was quite surgeon dependent, and no consensus-based strategy was proposed.

Objective: The study aimed to propose a radiographic classification of PCMs to facilitate treatment selection and predict neurological outcomes.

Methods: Clinical and radiographic data of 513 cases of surgically treated PCMs between May 2011 and August 2018 were retrospectively reviewed, and follow-up was accomplished in 483 (94.2%) cases. Skull base compartments surrounding petrous apex included (1) petrous apex itself; (2) Meckel cave, cavernous sinus, and/or middle cranial fossa; (3) sellar area and/or sphenoidal sinus; (4) contralateral clivus and/or petrous apex; (5) invasion to CPA region and lateral to internal auditory meatus; and (6) lower third clivus. All PCMs were classified into seven subtypes based on the regions potentially involved by PCMs: type I (region 1); type II (region 1 plus 2); type III (region 1 plus 3); type IV (region 1 plus 4); type V (region 1 plus 5); type VI (region 1 plus 6); and type VII (region 1 plus 2 regions or more). Surgical approach was selected based on the classification, and the association with outcome was evaluated.

Results: This consecutive cohort included 372 females (72.5%) with a mean age of 49.7 years. Mean preoperative and postoperative KPS at discharge was 78.5 and 66.2, respectively, and recent KPS was 77.8. Retrosigmoid approach (n = 47), anterior transpetrosal (n = 289), presigmoid retrolabyrinthine approach (n = 81), far lateral approach (n = 23), frontal-temporal approach (n = 42), and others (n = 31). Gross total resection was achieved in 293 cases (57.1%) which was a bit greater than that of our early series. Surgical mortality and morbidity rates were 1.4% (n = 7) and 48.0% (n = 246), respectively. Mean follow-up duration was 46.5 months, and the recurrent rate was 2.7% (13/483). Surgical morbidity was different between various subtypes but that was significantly higher in type VII group (p < 0.001) as well as the lesion size that was largest in type VII group (p = 0.003). Other adverse factors for neurological outcome included brainstem edema, subarachnoid space, extent of surgical resection, preoperative KPS score, and intraoperative findings (adhesion to neurovascular structure and/or vessel encasement). The association between subtypes and neurological outcome was significant (p = 0.013) but compromised after adjustment for surgical approach (p = 0.116).

Conclusion: The radiological classification facilitated surgical approach decision, and total resection could be improved via suitable approach. Follow-up duration should be prolonged to validate the reasonability of the classification.

 

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No conflict of interest has been declared by the author(s).