Classification of petroclival meningiomas and selection of surgical approach

Abstract

Objective To analyze the classification of petroclival meningiomas according to the tumor extension on magnetic resonance imaging ( MRI ) and choice of surgical approach.Methods The clinical data of 318 cases of petroclival meningiomas were retrospectively analyzed.The cases were classified into eight types:petrous apex,cavernous sinus,sphenopetrosal,petroclival,petroclival - cavernous sinus,cerebellopontine angle (CPA),clival and extensive types.The pre- and post -operative statuses were evaluated by Karnofsky Performance Scale (KPS).Results 248 patients were included in the study with a mean preoperative KPS of 73.7 ± 10.3. The most frequent approaches were presigmoid transpetrosal approach (49.6％) followed with subtemporal transpetrosal and transtentorial approach/ Kawase' s approach (STTA/KA) (35.1％ ).Complete resection (Simpson Grade Ⅰ or Ⅱ ) was achieved in 52.4％ patients.The most frequent approach of the first three types was STTA/KA ( 53.7％ ) and presigmoid transpetrosal approach (63.8％) in the latter five types,and the different proportion of approaches used between the two groups was significant (x2 =27.461,P ＜ 0.001 ).The complication rate of cranial nerves Ⅵ,Ⅶ and Ⅷ of presigmoid transpetrosal approach was higher than that of STTA/KA.The recent KPS was 75.8 ±26.9 without statistical difference from preoperative KPS (t =- 1.321,P =0.188 ).Compared with preoperative status,57.7％ patients were improved and 19.0％ were stabilized at recent evaluation.Conclusions Classification of petroclival meningiomas will contribute to the approach selection.STTA/KA approach is fit for the first three types,meanwhile,presigmoid transpetrosal approach is suitable for the latter five types. Comprehensive preoperative evaluation is essential to achieve individualized treatment and favorable prognosis. Key words: Meningioma; Petroclival; Presigmoid approach; Subtemporal approach; Classification