Trigeminal neuralgia and hemifacial spasm associated with vertebrobasilar artery tortuosity

Congenital and acquired anomalies of the basilar artery: A pictorial essay

INTRODUCTION

The basilar artery is one of the two cases in our body where an arterial vessel is formed by the union of two others - the vertebral arteries. It provides vascular supply to essential structures for the main vital functions; the posterior cerebral arteries originate from it as terminal branches, and form part of the anastomotic circle of Willis.

IMAGING FINDINGS

Congenital and acquired anomalies of the basilar trunk are described. We provide a schematic and detailed representation of normal anatomical variants - mainly represented by the fenestrated basilar artery or the persistence of carotid-basilar anastomosis; course anomalies are also illustrated, with reference to neuro-vascular conflicts and dolichoectasia. Among congenital anomalies, this pictorial review also shows the variants of the basilar origin, such as in the case of basilar trunk arising from only one of the two vertebral arteries, and the calibre changes - which are represented by aneurysm and hypoplasia. The latter appears to be a risk factor for posterior circulation stroke, when associated with a bilateral posterior foetal variant.Among the acquired forms, this pictorial essay describes some clinical cases of dissections, non-congenital aneurysms, thrombosis and tumour with vascular encasing or compression of basilar artery.

CONCLUSION

CT angiography and MRI allow us to study the posterior intracranial circulation in detail, providing useful pre-treatment information. Therefore, knowledge of congenital or acquired anomalies of the basilar artery is essential for radiologists, neuroradiologists and neurosurgeons.

Fully Endoscopic Microvascular Decompression for Trigeminal Neuralgia Caused by Vertebrobasilar Artery: A Case Series Review: 2-Dimensional Operative Video

BACKGROUND AND OBJECTIVE

Microvascular decompression (MVD) is the most definitive and preferred surgical treatment for trigeminal neuralgia (TN). Treatment of TN caused by the vertebrobasilar artery (VBA) has been reported to be challenging and less satisfactory in complications and recurrence. Endoscopy has been implemented to provide a comprehensive view of neurovascular conflicts and minimize brain tissue stretch injury while exploring the trigeminal nerve. However, there are few retrospective studies on the treatment of TN caused by VBA by fully endoscopic microvascular decompression (E-MVD). This article aimed to illustrate the safety and efficacy of E-MVD for TN caused by the VBA.

METHODS

Clinical data for 26 patients with TN caused by the VBA who underwent E-MVD from 2019 to 2022 were retrospectively analyzed. The characteristics of vertebrobasilar-associated TN were summarized. The safety and efficacy of E-MVD for vertebrobasilar-associated TN were estimated based on the analysis of intraoperative manipulation, postoperative symptom relief, and complications.

RESULTS

Intraoperatively, the vertebrobasilar artery was regarded as a direct offending vessel in all 26 patients with TN, the vertebral artery in 18 (69.23%) and the basilar artery in 10 (38.46%). In addition to the vertebrobasilar artery, other vessels involved included the superior cerebellar artery in 12 patients, anterior inferior cerebellar artery in 9, posterior inferior cerebellar artery in 1, and veins in 4. All patients underwent E-MVD, and TN was entirely resolved in 26 (100%) patients immediately postoperatively. During the follow-up period of 12-45 months, no recurrence or serious complications were found. There were no serious postoperative complications, such as cerebellar swelling, intracranial hemorrhage, or death.

CONCLUSION

E-MVD for vertebrobasilar-associated TN is effective and safe.

[Anterior transpetrosal (Kawase) approach for petroclival meningioma with trigeminal neuralgia: case report and literature review]

The authors present a patient with petroclival meningioma complicated by trigeminal neuralgia. Resection of tumor via anterior transpetrosal approach with microvascular decompression of the trigeminal nerve was performed. A 48-year-old female patient presented with left-sided (V1-V2) trigeminal neuralgia. Magnetic resonance imaging revealed a tumor 33´27´25 mm with a base adjacent to the top of petrous part of the left temporal bone, tentorium cerebelli and clivus. Intraoperative examination revealed true petroclival meningioma extending to trigeminal notch of petrous part of temporal bone. There was additional compression of trigeminal nerve by caudal branch of superior cerebellar artery. Total resection of tumor was followed by disappearance of vascular compression of trigeminal nerve and regression of trigeminal neuralgia. Anterior transpetrosal approach provides early devascularization and resection of true petroclival meningioma, as well as wide imaging of anterolateral surface of the brainstem, identification of neurovascular conflict and vascular decompression.

[Interposition and transposition techniques of vascular decompression for hemifacial spasm]

OBJECTIVE

To analyze the vessels compressing facial nerve root exit zone and efficacy of interposition and transposition techniques of vascular decompression for hemifacial spasm.

MATERIAL AND METHODS

Vascular compression was evaluated in 110 patients. Implant interposition between vessels and nerve was performed in 52 cases, transposition of arteries without contact between implants and nerve - in 58 patients.

RESULTS

Compressing vessels were anterior (44), posterior (61) inferior cerebellar, vertebral (28) arteries and veins (4). Multiple compressing vessels were found in 27 cases. Premeatal meningioma and jugular schwannoma were accompanied by vascular compression in 2 cases. Immediate regression of symptoms was observed in 104 patients, partial regression - in 6 patients. Transient facial paresis (4) and impaired hearing (5) were noted after implant interposition. Redo vascular decompression was performed in one case.

CONCLUSION

The most common compressing vessels were cerebellar arteries, vertebral artery and veins. Transposition of arteries is highly effective technique with low incidence of VII-VII nerve dysfunction but relatively slow regression of symptoms.

Macrovascular Decompression with the Transposition Method Using Teflon Sling for Trigeminal Neuralgia Caused by the Vertebrobasilar Artery

OBJECTIVE

Complete separation of the vertebrobasilar artery (VBA) from the trigeminal nerve by microvascular decompression is technically challenging. This paper evaluates the transposition method using Teflon sling for trigeminal neuralgia (TN) caused by the VBA.

METHODS

Retrospective review of 32 patients including 2 patients with tic convulsif. Mobilization of the VBA in the anteromedial-caudal direction and repositioning of the VBA using Teflon sling and fibrin glue were performed. Pre- and postoperative pain were evaluated with the Barrow Neurological Institute (BNI) pain intensity score. Duration of surgery and postoperative neurologic complications were reviewed.

RESULTS

Preoperative BNI score ranged from III to V. Postoperative BNI score I was observed in 30 patients, II in 1 patient, and V in 1 patient as recurrence. Abducens nerve palsy was observed in 9 patients but was transient in 8. Permanent hearing loss was observed in 6 patients. Transient mild lower cranial nerve palsy was recorded in 2 patients with tic convulsif. Average surgical time was 290 minutes.

CONCLUSIONS

Our method for trigeminal neuralgia caused by VBA was very effective, but the complication rate of cranial nerve disorders was also high. A high rate of complications implied the technical difficulty of extensive vascular mobilization requiring long duration of surgery. Macrovascular decompression surgery is more descriptive of this surgery instead of microvascular decompression surgery.

Microvascular decompression for trigeminal neuralgia attributable to the vertebrobasilar artery: decompression technique and significance of separation from the nerve root

BACKGROUND

Separation of the vertebrobasilar artery (VBA) from the trigeminal nerve root in microvascular decompression (MVD) is technically challenging. This study aimed to review the clinical features of VBA involvement in trigeminal neuralgia and evaluate surgical decompression techniques in the long term.

METHODS

We retrospectively reviewed the surgical outcomes of 26 patients (4.4%) with VBA involvement in 585 consecutive MVDs for TGN using a Teflon roll for repositioning the VBA. The final operative status of the nerve decompression was categorized into two groups: the separation group and the contact group. Separation of the VBA from the nerve root was completed in 13 patients in the separation group, and slight vascular contact remained in the remaining 13 patients of the contact group. The clinical features of VBA-related TGN were investigated and the operative results were analyzed.

RESULTS

Multiple arteries are involved in neurovascular compression (NVC) in most cases. The anterior inferior cerebellar artery was the most common concomitant artery (69%). The site of the NVC varies from the root entry zone to the distal portion of the root. All patients were pain-free immediately after surgery and maintained medication-free status during the follow-up period, except for one patient (3.8%) who had recurrent facial pain 8 years after surgery. Postoperative facial numbness was observed in six patients (23%). Of these, one patient showed improvement within 3 months and the other five patients had persistent facial numbness (19.2%). Other neurological deficits include one dry eye, one diplopia due to trochlear nerve palsy, two decreased hearing (< 50 db), two facial weaknesses, and two cerebellar ataxia. Although most of them were transient, one dry eye, two hearing impairments, and one cerebellar ataxia became persistent deficits. Statistical analyses revealed no difference in surgical efficacy or complications in the long term between the two groups.

CONCLUSIONS

Slightly remaining vascular contact does not affect pain relief in the long term. Our study indicated that once the tense trigeminal nerve is loosened, further attempts to mobilize the VBA are not necessary.

Location of the abducens nerve stretched by a tortuous vertebrobasilar artery in trigeminal neuralgia

BACKGROUND

Trigeminal neuralgia (TGN) caused by the vertebrobasilar artery (VBA) is uncommon. The abducens nerve root is frequently dislocated by a tortuous VBA near the trigeminal nerve root. This unusual location of the root is not well known. This study aimed to investigate the location of the stretched abducens nerve root.

METHODS

The objective is 26 patients with VBA-related TGN who underwent microvascular decompression (MVD). We retrospectively investigated the course of the abducens nerve root with magnetic resonance imaging (MRI) with three-dimensional (3D) imaging and surgical findings. The displacement of the abducens nerve root on the affected side was compared to the contralateral side.

RESULTS

The abducens nerve root was distorted by a tortuous VBA (46.2%) or the anterior inferior cerebellar artery (53.8%). The average length of the cisternal segment was stretched to 23.4 mm versus 12.4 mm on the contralateral side. The peak point of the elevated abducens nerve root was mostly located rostro-medial (65.4%) or caudo-medial (34.6%) to the neurovascular compression site of the trigeminal nerve with a mean distance of 9.1 mm. Contact with the trigeminal nerve root was observed in 7 patients (26.9%). Three-dimensional imaging was consistent with the surgical findings and useful in predicting the location of the abducens nerve root. No abducens nerve palsy was noted in our series.

CONCLUSIONS

The abducens nerve root is located near the trigeminal nerve root in VBA-related TGN. Preoperative understanding of the unusual course of the abducens nerve root contributes to avoiding accidental nerve injury during MVD.

Microvascular decompression for trigeminal neuralgia caused by vertebrobasilar dolichoectasia: interposition technique versus transposition technique

BACKGROUND

Various techniques of microvascular decompression have been proposed for trigeminal neuralgia (TN) caused by vertebrobasilar dolichoectasia (VBD) with two main modalities: interposition and transposition. This retrospective study compares the outcomes of two techniques belonging to different modalities for VBD-associated TN.

METHODS

From January 2011 to April 2017, 39 patients underwent MVD for VBD-associated TN. The transposition method chosen was the biomedical glue sling technique. Patients were divided into the interposition group (n = 16) and the transposition group (n = 23). The radiologic data, intraoperative findings, complications, and outcomes were analyzed.

RESULTS

The 1-, 3-, and 5-year pain-free (BNI class I) maintenance rates were 100.0, 91.1, and 91.1%, respectively, in the transposition group and 87.5, 74.5, and 58.7% in the interposition group (p = 0.032). Postoperative complications were similar in both groups, but there was a trend for higher incidence of postoperative facial hypoesthesia using the interposition technique (p = 0.06).

CONCLUSION

In cases of VBD-associated TN, the transposition technique using biomedical glue was superior to the traditional interposition technique in maintaining a pain-free status, with no increase in the incidence of complication.

[Microvascular decompression in trigeminal neuralgia following vertebrobasilar dolichoectasia]

OBJECTIVE

To analyze our own results with literature data and substantiate microvascular decompression in patients with trigeminal neuralgia (TN) following vertebrobasilar dolichoectasia (VBD).

MATERIAL AND METHODS

A total of 504 patients with TN underwent surgery in 1998-2018. Patients with TN following VBD were included into a retrospective study. There were 4 men and 10 women aged 66 years (range 51-80). Outcomes were evaluated using BNI (Barrow Neurological Institute) scale. PubMed database was used for literature review.

RESULTS

TN caused by VBD was diagnosed in 2.8% of patients. Left-sided trigeminal pain was observed in 10 patients, right-sided - in 4 cases. One patient had concomitant hemifacial spasm. MVD followed by shielding of trigeminal nerve root with shredded Teflon was performed in all patients. We did not perform fixation of vertebrobasilar vessels. In one case, open partial trigeminal nerve root rhizotomy was done in addition to MVD. All patients had pain-free early postoperative period. There were no deaths or major complications. There was transient cranial nerve dysfunction lasting no more than three months (facial numbness - 1, IV nerve dysfunction - 1, VI nerve dysfunction - 1, transient partial facial palsy (House-Brackmann II) - 2, hipoacusia - 2 patients). There was no facial pain recurrence in our group. Mean follow-up period was 5.5 years (range 6 months - 16 years).

CONCLUSION

MVD is an effective option in the treatment of TN following VBD. In these cases, operation is technically more difficult compared to MVD with intact vessels. However, surgery is much more effective than all the available alternatives. The possibilities of vessel transposition in VBD with or without fixation are limited and ineffective. Teflon wool interposition at the points of conflict is an effective and sufficient technique.

Spasm Freedom Following Microvascular Decompression for Hemifacial Spasm: Systematic Review and Meta-Analysis

BACKGROUND

Hemifacial spasm (HFS) is a debilitating disorder characterized by intermittent involuntary movement of muscles innervated by the facial nerve. HFS is caused by neurovascular compression along the facial nerve root exit zone and can be treated by microvascular decompression (MVD). The goal was to determine rates and predictors of spasm freedom after MVD for HFS.

METHODS

A literature search using the key terms "microvascular decompression" and "hemifacial spasm" was performed. The primary outcome variable was spasm freedom at last follow-up. Analysis was completed to evaluate for variables associated with spasm-free outcome.

RESULTS

A total of 39 studies including 6249 patients were analyzed. Overall spasm freedom rate was 90.5% (5652/6249) at a follow-up of 1.25 ± 0.04 years. There was no significant relationship between spasm freedom versus persistent spasm and age at surgery, timing of follow-up, gender, disease duration, side of disease, or vessel type. Spasm freedom was more likely after an initial surgery versus a redo MVD (odds ratio 4.16, 95% confidence interval 1.99-8.68; P < 0.01).

CONCLUSIONS

MVD works well for HFS with cure rates >90% at 1-year follow-up in 6249 patients from 39 studies. A significant predictor of long-term spasm freedom at 1 year was an initial MVD as compared to repeat MVD. The majority of published manuscripts on MVD for HFS are heterogeneous single-institutional retrospective studies. As such, a large-scale meta-analysis reporting outcome rates and evaluating significant predictors of spasm freedom provides utility in the absence of randomized controlled studies.

Treatment of Venous Hemorrhage Between Vestibulocochlear Nerve and Hypertrophic Flocculus During Microvascular Decompression Procedure for Hemifacial Spasm

Hemifacial spasm is a kind of painless, intermittent, involuntary, and irregular unilateral facial muscles convulsion. Microvascular decompression has become the standard surgical procedure for hemifacial spasm after years of popularization and development. In the article, the authors described in detail a therapeutic strategy for rapid intracranial venous bleeding between vestibulocochlear nerve and hypertrophic flocculus. When simple compression hemostasis failed, the authors applied fibrin glue and gelatin sponges for hemostasis and finally successfully controlled venous bleeding. The patient's symptoms were completely relieved after operation. Routine postoperative examination of head computed tomography revealed no intracranial hemorrhage. The combination of fibrin glue and gelatin sponges may be a possible solution for complicated and intractable venous hemorrhage during microvascular decompression procedure in some patients with hemifacial spasm.