COMPARISON OF CONVENTIONAL AND SKULL BASE SURGICAL APPROACHES FOR THEEXCISION OF TRIGEMINAL NEURINOMAS

Trigeminal neurinomas have traditionally been excised through conventi onal approaches. Because symptomatic tumor recurrence exceeds 50% afte r conventional procedures, the authors evaluated the use of skull base approaches to achieve complete resection and a lower rate of symptoma tic recurrence. Comparisons of skull base with conventional approaches to trigeminal neurinomas have been limited to small series with short -term follow-up periods. The authors reviewed their experiences with c onventional (frontotemporal transsylvian, subtemporal-intradural, subt emporal-transtentorial, and suboccipital) and skull base (frontotempor al extradural-intradural, frontoorbitozygomatic, subtemporal anterior petrosal, and presigmoid posterior petrosal) surgical approaches for t he excision of trigeminal neurinomas. in this paper they report the re sults of 15 patients with trigeminal neurinoma who underwent 27 surgic al procedures between 1980 and 1990. Seventeen of the procedures used conventional and 10 used skull base approaches. Ah patients had tumors arising from Meckel's cave and the porus trigeminus either initially or on recurrence. Tumors located in the cavernous sinus recurred most frequently (83%); other tumors that recurred frequently were those loc ated in Meckel's cave and the porus trigeminus (67%), and the posterio r fossa (17%). The tumor extended into the anterolateral wall of the c avernous sinus in 38% of patients with cavernous sinus involvement. Tu mor exposure and ease of dissection were superior with skull base appr oaches. Residual or recurrent tumors were found in 65% of patients fol lowing conventional approaches compared with 10% of patients following skull base approaches. Using skull base approaches, the surgeon was m ore accurate (90%) in estimating tumor excision than when using conven tional approaches (43%). Perioperative complications were similar with both. The authors discuss the indications, advantages, and limitation s of each approach. Based on anatomical considerations, they propose a strategy to best resect these tumors.