Suprameatal extension of retrosigmoid approach for microvascular decompression of trigeminal nerve: Case report

• We did an asterional craniectomy, through a retrosigmoid approach, but, we observed absence of vascular compression in the entrance to the Trigeminal Nerve.
• Once performed the removal of the suprameatal tubercle, and Meckel’s segment of the Trigeminal nerve exploration was done, a vascular compression of the nerve by a branch of the superior cerebellar artery was found, just behind the trigeminal pore.
• When, the vascular compression is not evident at exploring the cerebellopontine angle, it is important to note that association of a prominent suprameatal tubercle may be able to hide a vascular compression of the nerve in this region.

IntroductionTrigeminal neuralgia is produced in a significant number of cases by vascular compression at the level of cisternal segment of the nerve at the entry of the pons. It is common to find superior cerebellar artery (SCA) responsible for this compression. The retrosigmoid approach (RA), with asterional craniectomy, clearly exposes the cisternal portion of the trigeminal nerve (TN).Presentation of caseWe describe in this case report how vessels at the trigeminal pore level known as “Meckel’s segment” can compress the TN. This situation is unusual. One of the reasons why the compression of this Meckel’s segment level could be overlooked is a suprameatal tubercle (ST) prominence that would prevent trigeminal pore visualization through retrosigmoid approach.DiscussionThe suprameatal extension of this approach has been described for other purposes, especially in tumors invading Meckel’s cave resection. We could not find publications for the use of the resection of the suprameatal tubercle in the retrosigmoid approach for microvascular decompression of the trigeminal neuralgia.ConclusionMicrovascular decompression of the TN is an effective treatment for trigeminal neuralgia, however in some cases, in which vascular compression is not evident when exploring the cerebellopontine angle, it is important to note that association of a prominent ST can hide a vascular compression of the nerve in this region.