Management of Petrous Endostosis in Posterior Fossa Procedures for Trigeminal Neuralgia

Abstract

Petrous endostosis is an uncommon finding in posterior fossa procedures for TN (3.4%). However, it can obscure the region of neurovascular conflict, which is venous compression in these cases. We have found that drilling away endostosis or using endoscopic-assisted microsurgery increases the chances of good outcome and avoids unnecessary rhizotomy. All magnetic resonance imaging scans should be inspected for evidence of petrous endostosis and, when present, a bone window computed tomographic scan should be performed to clarify the image and check for the presence of petrous air cells. If the endostosis is drilled, failure to detect and to seal these air cells thoroughly can result in postoperative cerebrospinal fluid rhinorrhea. Attention to these details will optimize the surgical results. However, the use of an angled endoscope avoids this problem and is now our preferred method.

Microvascular decompression as a surgical management for trigeminal neuralgia: A critical review of the literature

“…Interestingly, the rate of negative exploration is quite variable, 18-28.5% depending on the experience of the surgeon. [36] In the retrospective cohort study of MVD by Kalkanis and colleagues the morbidity rates were signiÞ cantly lower at high-volume hospitals and with high-volume surgeons. The mortality rate was 0.3%, and the rate of discharge other than to home was 3.8%.…”

“…[36] Thereafter, Barker et al, emphasized MVD by demonstrating a 70% cure rate in a 10-year follow-up study. [9] However, direct comparisons between various series are hindered by different deÞ nitions of operative success regarding the recurrence rate of tic pain after MVD that was done using actuarial methods.…”

“…[9] Jannetta noted signiÞ cant vascular compression in 96% of patients with TN and in 12% of them it was due to a vein. [36] However, the reasons for the high recurrences in patients with venous compression are not clear. Re-exploration is often the strategy in patients with recurrence of symptoms.…”

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).…”

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

“…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.…”