Bridging veins and veins of the brainstem in microvascular decompression surgery for trigeminal neuralgia and hemifacial spasm

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>In microvascular decompression surgery for trigeminal neuralgia and hemifacial spasm, the bridging veins are dissected to provide the surgical corridors, and the veins of the brainstem may be mobilized in cases of venous compression. Strategy and technique in dissecting these veins may affect the surgical outcome. The authors investigated solutions for minimizing venous complications and reviewed the outcome for venous decompression.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>The authors retrospectively reviewed their surgical series of microvascular decompression for trigeminal neuralgia and hemifacial spasm in patients treated between 2005 and 2017. Surgical strategies included preservation of the superior petrosal vein and its tributaries, thorough dissection of the arachnoid sleeve that enveloped these veins, cutting of the inferior petrosal vein over the lower cranial nerves, and mobilization or cutting of the veins of the brainstem that compressed the nerve roots. The authors summarized the patient characteristics, operative findings, and postoperative outcomes according to the vascular compression types as follows: artery alone, artery and vein, and vein alone. They analyzed the data using chi-square and 1-way ANOVA tests.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>The cohort was composed of 121 patients with trigeminal neuralgia and 205 patients with hemifacial spasm. The superior petrosal vein and its tributaries were preserved with no serious complications in all patients with trigeminal neuralgia. Venous compression alone and arterial and venous compressions were observed in 4% and 22%, respectively, of the patients with trigeminal neuralgia, and in 1% and 2%, respectively, of those with hemifacial spasm (p &lt; 0.0001). In patients with trigeminal neuralgia, 35% of those with artery and venous compressions and 80% of those with venous compression alone had atypical neuralgia (p = 0.015). The surgical cure and recurrence rates of trigeminal neuralgias with venous compression were 60% and 20%, respectively, and with arterial and venous compressions the rates were 92% and 12%, respectively (p &lt; 0.0001, p <jats:italic>=</jats:italic> 0.04). In patients with hemifacial spasm who had arterial and venous compressions, their recurrence rate was 60%, and that was significantly higher compared to other compression types (p = 0.0008).</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>Dissection of the arachnoid sleeve that envelops the superior petrosal vein may help to reduce venous complications in surgery for trigeminal neuralgia. Venous compression may correlate with worse prognosis even with thorough decompression, in both trigeminal neuralgia and hemifacial spasm.</jats:p></jats:sec>

Individual variations of the superior petrosal vein complex and their microsurgical relevance in 50 cases of trigeminal microvascular decompression

“…This emphasizes the worth of preoperative and intraoperative evaluations of the whole SPVC rather than the main SPV(s) only [11]. The TPv was the most common offending vein, similar to previous reports [8,32]. Corresponding intraoperative photographs of the same case.…”

“…This is because of the very medial course of the TPv and medial type III drainage of the SPV 3 into the SPS beyond the microsurgical field. ALMv anterior lateral marginal vein, bFFE balanced fast field echo, CPA cerebellopontine angle, SCA superior cerebellar artery, SPV superior petrosal vein, SPVC superior petrosal vein complex, SPV1 first SPV, SPV2 second SPV, SPV3 third SPV, TG trigeminal nerve, TPv transverse pontine vein, v.CPF vein of cerebellopontine fissure, v.MCP vein of the middle cerebellar peduncle Although SPVC components commonly block the surgical exposure, preserving it is possible in many cases by utilizing adequate cisternal drainage and careful development of intervenous corridors [8,9,11,32]. This proved to be effective in the cases reviewed in this study.…”

Hemifacial spasm caused by the brainstem developmental venous anomaly: A case report and review of the literature

“…[1,13,14,20,21,23,27,31] Venous compression of the root of the facial nerve is rare in HFS and the veins alone as offending vessels are reported in 0%-7.9%. [8,10,[28][29][30]33] It was shown that cure rates in HFS and trigeminal neuralgia patients who had arterial and venous compressions were significantly lower compared to those with arterial compression alone. [28] Jannetta first described small arteriole in contact and a minute venule crossed the caudal aspect of the facial nerve REZ.…”

“…[8,10,[28][29][30]33] It was shown that cure rates in HFS and trigeminal neuralgia patients who had arterial and venous compressions were significantly lower compared to those with arterial compression alone. [28] Jannetta first described small arteriole in contact and a minute venule crossed the caudal aspect of the facial nerve REZ. e arteriole was mobilized and held away with shredded Teflon, and the venule considered as true causative vessel was coagulated and divided, and patient's HFS slowly disappeared.…”

“…Dual compression of the REZ by veins and arteries is also associated with HFS, but venous origin alone is rarely reported. [8,28,30,33] ere are only few cases described the HFS associated with the brainstem developmental venous anomaly (DVA), also known as cerebral venous angioma. [4][5][6]25] We present a rare case of HFS caused by the brainstem DVA treated with microvascular decompression (MVD).…”