Computed Tomography−Guided Posterolateral Transsacral Ala Approach to Presacral L5 Schwannoma: Technical Note

Background: Presacral schwannomas are rare benign tumors that may reach large size before becoming symptomatic. Total surgical removal has been considered the best treatment option. Tumors arising from the presacral area are commonly managed through anterior approaches, whereas posterior approaches are used for pure intrasacral tumors or large lesions with both intrasacral and presacral extension, alone or in combination with anterior approaches. Methods: We describe a quick and minimally invasive navigation-guided posterolateral approach to a right presacral L5 schwannoma. The lesion was microsurgically removed through high-speed drilling of the upper portion of the right sacral ala, under intraoperative neurophysiologic monitoring. Results: The postoperative course was unremarkable, and the patient experienced improvement in his sensory disturbance. Postoperative magnetic resonance imaging and computed tomography scan showed the complete excision of the lesion and the removal of the upper sacral ala with preservation of the right L5-S1 articular complex. The histologic examination confirmed a schwannoma (World Health Organization grade I). Conclusions: The posterolateral transsacral ala approach may represent a minimally invasive option in the surgical management of presacral well-circumscribed benign tumors. Spinal navigation could be properly used to facilitate lesion exposure and to minimize the bone removal. The intraoperative neurophysiologic monitoring is an essential tool for the preservation of the lumbosacral nerve roots.