Endoscopic Endonasal Approach to Meckel's Cave for Treatment of Trigeminal Meningoencephalocele: Bolster Technique

Background: Meningoencephaloceles in Meckel's cave are rare defects within the middle cranial fossa, typically presenting no symptoms but possibly involving prolapsed trigeminal nerve roots, leading to Trigeminal Neuralgia (TGN). Our understanding of their surgical management and outcomes is currently limited. Transcranial Approaches to Meckel’s cave are challenging due to the long working corridor and required brain retraction. Innovative endoscopic endonasal approaches to the middle fossa have great potential to address Meckel’s cave lesions with minimal brain retraction. We describe successfully treating trigeminal neuralgia as a result of a middle fossa meningoencephalocele using an endoscopic endonasal approach to Meckel’s cave.

Case Description: Three patients who presented with symptoms of classical trigeminal neuralgia were found to have meningoencephalocele in Meckel’s cave on MRI (Fig 1). A standard endoscopic endonasal transpterygoid approach was used to get to the foramen rotundum and drill it away to enlarge the opening into the Gasserian ganglion ([Fig. 2]). There was no evidence of a CSF leak but the trigeminal nerve roots were seen to herniate inferiorly. To bolster the rootlets, several Teflon splints were fashioned ([Fig. 3]). These were placed into the place below the Gasserian ganglion using the enlarged foramen rotundum. They were also placed posteriorly and laterally to protect the different divisions of the trigeminal nerve. Once we were satisfied that the branches of the nerve had been bolstered up and the encephalocele had thus been reduced, we proceeded to close in a standard fashion. All 3 patients experienced significant relief in their trigeminal neuralgia symptoms postoperatively.

Conclusion: The endoscopic endonasal transpterygoid approach provides optimal exposure to Meckel’s cave without brain retraction. We discuss the clinical details, operative techniques, and outcomes of using an endoscopic transpterygoid approach to safely treat meningoencephaloceles of the middle fossa causing trigeminal neuralgia.

Fig. 1 Axial and coronal T2 Fiesta sequences demonstrating cystic enlargement within the Meckel’s cave (A; Right, B; Right, C; Left) representing trigeminal meningoencephalocele.

Fig. 2 Access to foramen rotundum via Endoscopic Endonasal Transpterygoid Approach.

Fig. 3 Teflon splints to bolster trigeminal nerve roots.

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Artikel online veröffentlicht:
05. Februar 2024