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

Abstract

HighlightsWe 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.

Endoscopic vascular decompression in trigeminal neuralgia

“…Excision of this tubercle may be required to see conflicts when microscopic technique is performed, and such conflict can be missed otherwise. Distal conflicts near the ganglion are also difficult to visualize using the microscope alone and could demand use of the endoscope in such surgeries (43). We did not require any brain retraction in our series and similar observation were made in other series (1,4,15,23,28,34).…”

Surgical Nuances and Predictors of Requirement for Suprameatal Tubercle Removal in Microvascular Decompression for Trigeminal Neuralgia

“…15 Several factors are known to be associated with the technical difficulty of trigeminal nerve MVD, including the involvement of dolichoectatic vertebrobasilar arteries as an offending vessel, 17 well-developed SPV complexes as a vascular obstacle, 14 and enlarged SMTs as a bony obstacle. [3][4][5][6][7][8][9][10] Multivariate analysis with logistic regression, performed in the present study, indicated that an enlarged SMT and a multiple number of offending vessels are indicative of the need for SMT removal during trigeminal MVD. Shenouda and Coakham 9 reported that multiple offending vessels (SCA in combination with vein) were involved in 9 of 15 (60%) cases who underwent SMT removal (►Table 4).…”

“…Drilling the SMT, however, requires meticulous maneuvers and experience, due to the potential risk of injury to the surrounding neurovasculature or CSF leak. [3][4][5][7][8][9] The working corridor for SMT removal is restricted by important neurovascular structures: superiorly by the SPV and trigeminal nerve, and inferiorly by the facial and vestibulocochlear nerves. Therefore, special attention is required, to avoid injury to these important neurovascular structures.…”

“…2 In such cases, the removal of the enlarged SMT may improve the surgeon's visualization of the NVC site. [3][4][5][6][7][8][9][10] SMT removal, however, is a technically demanding procedure, which requires meticulous maneuvers and experience, due to the potential risk of injuring the surrounding neurovasculature and cerebrospinal fluid (CSF) leakage. [3][4][5][6][7][8][9][11][12][13] Of 197 consecutive patients who underwent MVD at our institute over 7 years (2011)(2012)(2013)(2014)(2015)(2016)(2017), 20 required SMTremoval to complete the MVD.…”

Case report of unusual cause of trigeminal neuralgia: Trigeminal neuralgia secondary to enlarged suprameatal tubercle

“…Drilling of suprameatal tubercle give access to Meckel's cave and posterior part of middle cranial fossa [ 13 ]. However, drilling of supameatal tubercle maybe necessary in cases of microvascular decompression of trigeminal nerve if heavily calcified and enlarged tubercle encountered to expose the entire length of trigeminal nerve, especially when the offending vessel is not visualized under the enlarged tubercle [ [14] , [15] , [16] ]. Inoue et al reported EST in 48 (10.4%) of 461 patients treated by microvascular decompression for TN and 8 patients had resection of the enlarged tubercle (7 operated via retrosigmoid approach and 1 via anterior transpetrosal approach).…”