Patterns and variations in microvascular decompression for trigeminal neuralgia

Microvascular Decompression for Trigeminal Neuralgia with Complicated Offending Vessel Involving Trigeminocerebellar Artery: 2-Dimensional Operative Video

Microvascular decompression (MVD) is a well-established and definitive treatment option for trigeminal neuralgia (TN).1 However, complex vascular geometry and numerous offending vessels make it difficult to perform nerve decompression in certain cases.2 The trigeminocerebellar artery (TCA) is a unique branch of the basilar artery. The vessel is named the TCA because it supplies both the trigeminal nerve root and the cerebellar hemisphere.3 This anatomical variant may increase the risk of neurovascular compression in the trigeminal nerve. We present the case of a 74-year-old man with left TN in whom a TCA was one of the responsible compression vessels. Preoperative images revealed the ipsilateral anterior inferior cerebellar artery, well-developed TCA, and superior cerebellar artery, wherein these branches were all suspected to be involved in trigeminal nerve compression. In MVD, 3 arteries were suspected to compress the trigeminal nerve in 5 sites, and all of them needed to be meticulously dissected from the nerve root and decompressed. Moreover, 2 of them branched many short perforators to the brainstem. Three decompression procedures (transposition to the dura, transposition to the brain, and interposition) were performed to decompress the trigeminal nerve. Postoperatively, TN was completely resolved immediately. MVD for TN could be difficult to perform in cases with TCA, as in the present case, and rigorous procedures were required intraoperatively.

Fenestrated Aneurysm Clip Trigeminal Decompression after CyberKnife Treatment Failure

Objective  This article describes a novel technique for trigeminal nerve decompression in the setting of refractory trigeminal neuralgia (TN). Design  Technical note with an illustrative case example and operative video. Setting  Outpatient, inpatient, and operating room of a quaternary neurosurgical referral center. Participant  A woman in her early 70s who had previously undergone linear accelerator-based stereotactic radiotherapy (i.e., CyberKnife) and achieved 2 years of partial pain relief. However, facial pain, numbness, and parasympathetic dysfunction returned and became unbearable. Main Outcome Measure  Durable relief of TN. Results  Microvascular decompression was recommended for refractory TN. Intraoperatively, the trigeminal nerve was markedly attenuated from previous irradiation, with the superior cerebellar artery (SCA) loop embedded in the nerve at its root entry zone. The arterial loop was mobilized into a new position superior to the nerve, thus liberating it from the impingement. The tentorium was incised, and a fenestrated aneurysm clip was positioned such that the SCA loop was transmitted via the fenestration. The clip was applied across the tentorium, thus suspending the artery in a kink-free orientation that made no contact with the nerve. Conclusion  This procedure provided excellent neurovascular decompression without placing mechanical strain on the nerve, relieving the patient's persistent postirradiation TN. The technique could have broader applications for other challenging or atypical microvascular decompression procedures.

Exoscopic microvascular decompression for hemifacial spasm and trigeminal neuralgia

The 4K 3D exoscope system is becoming increasingly used in neurosurgery. Its 3D ultra-high-definition image is valuable in identifying and dissecting the delicate neural and vascular structures during microvascular decompression. In this video, the authors describe several nuances and details to perform the exoscopic microvascular decompression, including the exoscope layout and the modified supine position. Several illustrative case presentations highlight the benefits of exoscopic surgery. The authors' exoscopic microvascular decompression series of 159 patients showed noninferior surgical outcomes compared to the operative microscope with no significant increase in surgical risk. In conclusion, an exoscope can be a practical alternative to performing microvascular decompression. The video can be found here: https://stream.cadmore.media/r10.3171/2023.10.FOCVID23122.

Endoscope Assisted Microvascular Decompression for Trigeminal Neuralgia: Surgical Safety and Efficacy

BACKGROUND

The cranial nerve (CN) V and adjacent neurovascular structures are crucial landmarks in microvascular decompression (MVD). MVD of CN V is the most effective treatment for patients with drug-resistant trigeminal neuralgia (TN) diagnosis. The endoscope-assisted retrosigmoid approach (RSA) provides better exposure and less cerebellar retraction in the corridor towards the cerebellopontine angle (CPA).

METHODS

Five adult cadaver heads (10 sides) underwent dissection of the MVD in park bench position. MVD was simulated using microsurgical RSA, and the anatomical landmarks were defined. Microsurgical dissections were additionally performed along the endoscopic surgical path. Additionally, we present an illustrative case with TN caused by anterior inferior cerebellar artery (AICA) compression. The CN V and its close relationships were demonstrated. Endoscopic and microscopic three-dimensional pictures were obtained.

RESULTS

This study increases the anatomical and surgical orientation for CN V and surrounding structures. The CN V arises from the lateral part of the pons and runs obliquely upward toward the petrous apex. It has motor roots that leave from pons antero-supero-medial direction to the sensory root. The endoscopic instruments provide perfect visualization with minimal cerebellar retraction during MVD.

CONCLUSION

MVD surgically targets the offending vessel(s) leading to TN and aims to create a disconnected area. The combination of preoperative radiographic assessment with and anatomical correlation provides safe and effective application while facilitating selection of the most appropriate approach. The RSA allows satisfactory visualization for CN V. Endoscope-assisted microsurgery through the CPA is a challenge, it should be performed with advanced anatomical knowledge.

Surgical anatomy of sigmoid sinus with evaluation of its venous dominance for advances in preoperative planning

Microvascular decompression (MVD) is a widely adopted neurosurgery in treating cranial nerve diseases providing long-term pain relief. Improving surgical techniques has been a focus of recent studies. Venous structures such as the sigmoid sinus are essential to protect, and whose risk of destruction during surgery increases with size. The medical records of patients who went through MRI ahead of MVD surgery between Dec 2020 and Dec 2021 were reviewed. Section area of sigmoid sinus calculated from the MRI plane of auditory nerve showed a right dominance of the sinus. The improved method concerning the relationship between affected side and the dominant sigmoid sinus offered a better bone window and surgical field by planning the operation incision in advance. Intraoperative adjustment of the bone flap was avoided, and the risk of destructing the sigmoid sinus was reduced.

Effects of microvascular decompression on quality-of-life in trigeminal neuralgia patients aged 70 years and older

Background

Trigeminal neuralgia (TN) occasionally affects older adults, frequently worsens, and becomes refractory to medication. Older adult patients with TN may consider microvascular decompression (MVD) for their treatment. No study examines MVD effects on older adult TN patients' health-related quality of life (HRQoL). The present study evaluates the HRQoL of TN patients aged 70 years and older before and after MVD.

Methods

Adult TN patients who underwent MVD evaluated their HRQoL using the 36-Item Short-form (SF-36) Health Survey before and 6 months after MVD. The patients were divided into four groups according to their decade of age. The clinical parameters and operative outcomes were analyzed statistically. The SF-36 physical, mental, and role social component summary scores and eight domain scale scores were analyzed using a twoway repeated-measures analysis of variance (ANOVA) to compare the effects of age group and preoperative and postoperative time points.

Results

Among 57 adult patients (34 women, 23 men; mean age, 69 years; range, 30-89 years), 21 patients were in their seventies, and 11 were in their eighties. The SF-36 scores of patients in all age groups improved after MVD. Two-way repeated-measures ANOVA demonstrated a significant age group effect on the physical component summary and its physical functioning domain. A time point effect was significant on all component summaries and domains. There was a significant interaction between age group and time point effects on the bodily pain domain. These results suggested that patients 70 years and older had significant postoperative HRQoL improvement, but their improvement of physical-related HRQoL and multiple physical pain issues were limited.

Conclusion

Impaired HRQoL in TN patients aged 70 years and older can improve after MVD. Careful management of multiple comorbidities and surgical risks enables MVD to be an appropriate treatment for older adult patients with refractory TN.

Long-term follow-up of microvascular decompression for management of trigeminal neuralgia

Background

Trigeminal neuralgia (TN) is mostly caused by neurovascular compression of the trigeminal nerve and the root entry zone at the brain stem. Microvascular decompression (MVD) has been established as a standard treatment for trigeminal neuralgia in patients not adequately controlled by medications.

Objectives

Reporting the long-term outcome of MVD in our group of patients with follow-up period equal to or more than five years.

Patients and methods

Twenty-one patients operated by MVD for TN were followed up for at least five years, they were evaluated describing the patient criteria and operative findings, complications, and the long-term clinical outcome.

Results

Sixteen of the twenty-one patients had complete pain relief maintained for up to five years and three of them up to eight years. Two patients had significant improvement but with mild occasional pain not requiring medications only one of them had his occasional pain maintained till five years, three patients experienced persistent pain which was still there after five years one of them showed mild improvement in his pain after one year of follow-up. Complications were mild and/or transient most frequent were headache nausea and dizziness.

Conclusion

In the long-term follow-up, microvascular decompression still maintains its clinical benefit with most patients still pain free after at least five years and up to eight years. It is safe procedures and should be considered in every patient with failed medical treatment.

Global Trends and Hotspots in Trigeminal Neuralgia Research From 2001 to 2021: A Bibliometric Analysis

Background

In recent years, there have been an increasing number of studies on trigeminal neuralgia (TN). However, a scientific and comprehensive study of the current situation and trends in the field of TN research is lacking. The purpose of this study is to summarize and visualize the development, research hotspots, and future trends in TN based on a bibliometric approach.

Methods

Studies on TN published from 2001 to 2021 were obtained from the Web of Science Core Collection (WoSCC). Bibliometrics, CiteSpace, and VOSviewer tools were used for bibliometric analysis and visualization.

Results

In total, 4,112 documents were searched. The number of research articles in the field is generally on an upward trend, with the fastest growth in the number of articles from 2017 to 2020. Shanghai Jiao Tong University, Pittsburgh University, and Mayo Clinic are the three institutions with the most publications. Shiting Li and Zakrzewska JM are the most prolific author and top co-cited authors, respectively. The Journal of Neurosurgery is the most influential journal. The top 5 keywords in that time frame are TN, microvascular decompression, facial pain, stereotactic radiosurgery, and neuropathic pain.

Conclusion

This is the first comprehensive scientific bibliometric analysis of the global research field on TN over the past 21 years, providing a meaningful reference for further exploration of topical issues and research trends in the field.

Microvascular decompression for pediatric onset trigeminal neuralgia: patterns and variation

OBJECTIVES

Pediatric trigeminal neuralgia has been rarely reported in the literature, which were only 28 cases. Although microvascular decompression (MVD) has been widely accepted as effective therapy for trigeminal neuralgia, the etiology and surgical treatment of pediatric ones are seldom addressed. We report our experience with MVD for pediatric trigeminal neuralgia patients with emphasis on the vascular conflict patterns and surgical skills.

METHODS

This retrospective report included 11 pediatric TN patients, who underwent MVD and were followed for 3-86 months. The data were retrospectively analyzed with emphasis on the clinical features.

RESULTS

This series included 4 boys and 7 girls with average age of 13 ± 3.4 years old, their onset age were from 7 to 18 years old. The singular vein and combined artery/vein conflictions account for 7/11. 9 (81.8%) patients achieved immediate excellent outcomes. One recurrence was observed after 5 months and refused the second surgery.

CONCLUSIONS

The etiology of pediatric onset trigeminal neuralgia is still vascular conflict, whose patterns are different from adults, of which combined artery/vein and singular venous compression patterns have a much more higher proportion. Because of the smaller operative space and fragile-thin venous wall with adhesion to other structures, it is much more difficult to decompress the trigeminal nerve among pediatric patients. Sufficient arachnoid release, full exploration, and decompression along the trigeminal nerve were necessary, which will increase the excellent rate among pediatric patients.

Classification and Management of Pontecerebellar-Petrosal Bridging Veins

INTRODUCTION

The risks and benefits of coagulating intradural venous elements during a retrosigmoid approach for trigeminal neurovascular decompression has not been accurately established. The objectives of this study are to identify the veins that drain into the superior petrosal sinus, classify them in relation to the suprameatal tubercle and determine the implication of their coagulation.

MATERIAL AND METHODS

A retrospective study of 3D surgical videos of retrosigmoid approaches for trigeminal neurovascular decompression from the LINT (Laboratory of Neurosurgical Innovations of Tucumán) digital archive was carried out. The veins encountered were classified into 3 groups: retromeatal, meatal and premeatal. The neurosurgical postoperative complication scale proposed by Landriel et al. was utilized to assess complications from venous coagulation. A Grade 0 was added for patients without complications. The STATA 14 program was utilized for statistical analysis.

RESULTS

The pontocerebellar-petrosal veins of 28 patients who underwent trigeminal decompressive surgery were analyzed. In 7 cases these were found in the retromeatal region; 100% were sacrificed. 11 cases revealed veins within the meatal region; 90,91% were coagulated. Veins in the premeatal region were found in 14 cases; 57,14% were sacrificed. In the postoperative follow-up, 27 patients were grade 0 and 1 patient developed postoperative meningitis (grade Ib complication). No patient suffered vascular complications.

CONCLUSION

The venous elements identified in trigeminal neurovascular decompressive surgery are variable. We propose classifying them into retromeatal, metal and premeatal groups. Retromeatal and meatal veins can be safely sacrificed for appropriate visualization of the neurovascular conflict. The premeatal venous elements should be coagulated only in justified cases.

Polyvinyl Alcohol Sponges to Facilitate Cerebral Bypass Surgery: Technical Note

OBJECTIVE

The standard way of isolating bypass vessels from surrounding structures during cerebral bypass surgery has been to use a rubber dam or neurosurgical patty. Here, the use of polyvinyl alcohol (PVA) sponges is described as a possible upgrade from these traditional bypass dams.

METHODS

PVA sponges were used to isolate bypass arteries from surrounding tissues during microvascular anastomosis in 25 patients undergoing bypass surgery at our institution.

RESULTS

There were no adverse events related to the use of PVA for microvascular anastomosis. PVA sponges offered some specific advantages when compared with rubber and cottonoid dams.

CONCLUSIONS

Although preliminary, our experience using PVA sponges during microvascular anastomosis suggests some of their properties can facilitate cerebral bypass surgery.

Three-dimensional morphology of the superior cerebellar artery running in trigeminal neuralgia

The superior cerebellar artery (SCA) is the most frequent offending vessel in trigeminal neuralgia. This study aims to elucidate the patterns of the SCA running in 34 patients with typical trigeminal neuralgia using three-dimensional computer graphics. The SCA which runs in the medial aspect of the trigeminal nerve compressed predominantly the root entry zone at the distal segment of the caudal loop. Meanwhile, the SCA which runs in the cranial or lateral aspect of the trigeminal nerve compressed predominantly the mid-third portion at the proximal segment of the caudal loop. The site of neurovascular compression differed depending on the shape of the initial segment of SCA. Transposition methods could not be performed in several patients with arch-shaped SCA. Three-dimensional computer graphics revealed different characteristics of the SCA running in trigeminal neuralgia depending on the site of neurovascular compression and shape of the SCA. These differences might affect procedures for microvascular decompression.

Pulsatile tinnitus caused by pneumocephalus after Janneta surgery

Pulsatile tinnitus of nonvascular origin is rare. We herein present a case of pulsatile tinnitus complicated with Jannetta surgery due to a communication created between the drilled mastoid cells and epidural space. She was successfully cured by otological surgery where the mastoid tip was packed with bone cement. A 68-year-old woman was referred to the previous hospital with complaints of right autophony, aural fullness, hyperacusis to her footsteps, and pulsatile tinnitus for the past three years. She had received Jannetta surgery for right hemifacial spasm seven years before. The computed tomography (CT) of the right temporal bone showed bony dehiscence between the mastoid cells and posterior cranial fossa. She underwent otological surgery to obliterate the tip of the mastoid cavity with artificial bone cement (BIOPEX^Ⓡ) under general anesthesia. Her annoying aural symptoms were immediately abolished and she has been free from symptoms at ten months after surgery. It is critical to ensure the closure of any communication created between the middle ear and epidural space during surgeries in order to prevent the occurrence of pulsatile tinnitus.

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

OBJECTIVE 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. METHODS 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. RESULTS 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 < 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 < 0.0001, p = 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). CONCLUSIONS 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.

Development and Evaluation of a Preoperative Trigeminal Neuralgia Scoring System to Predict Long-Term Outcome Following Microvascular Decompression

BACKGROUND

Microvascular decompression (MVD) can be an effective intervention for trigeminal neuralgia (TN); however, an optimal system for patient selection and surgical outcome prediction has not been defined.

OBJECTIVE

To develop and validate a preoperative TN grading system for the prediction of long-term pain relief after MVD.

METHODS

This retrospective cohort study included consecutive patients suffering unilateral TN who underwent MVD with &gt;18-mo follow-up. A grading system was formulated using 3 previously validated preoperative characteristics. The primary end-point was long-term, pain-free status without use of medication. Ability to predict pain-free status was analyzed by multiple regression and assessed by area under the receiver operating characteristic curve (AUC). Clinical utility to predict MVD success and reduce unnecessary surgeries was assessed by decision-curve analysis.

RESULTS

Of 208 patients analyzed, 73% were pain-free without medication at &gt;18-mo follow-up. Pain-free status was predicted by classical TN type, positive response to carbamazepine and/or oxcarbazepine, and presence and nature of neurovascular compression demonstrated on MRI (all P &lt; .01). The TN grading system demonstrated good discriminatory ability for prediction of pain-free status (AUC 0.85, 95% CI 0.80-0.91). Decision-curve analysis demonstrated a net reduction of 20 cases likely to be unsuccessful per 100 patients evaluated with this grading system above a decision threshold of 80%.

CONCLUSION

This TN grading system reliably predicts long-term pain-free status without medications following MVD. The use of the TN grading system as part of a comprehensive work-up may reduce the number of unsuccessful operations.

Update on Trigeminal Neuralgia

PURPOSE OF REVIEW

To review current treatments for trigeminal neuralgia, with an emphasis on determining which patients may benefit from neurosurgical procedures.

RECENT FINDINGS

A detailed history is the most helpful tool for diagnosing trigeminal neuralgia (TN) and predicting response to neurosurgical treatments. Patients with classic trigeminal neuralgia will describe severe, unilateral, intermittent facial pain that is triggered by innocuous sensory stimuli. In most cases, pain is caused by compression of the trigeminal nerve by a blood vessel near the brainstem. Magnetic resonance imaging is necessary to rule out TN secondary to multiple sclerosis or tumor. Modern high-resolution T2 images may demonstrate neurovascular contact, particularly when analyzed by a neurosurgeon with expertise in TN. Initial management involves a trial of medication, usually carbamazepine or oxcarbazepine. Microvascular decompression (MVD) is safe and effective surgery, for patients with classic TN related to neurovascular compression. For patients with TN secondary to multiple sclerosis, and for patients who are otherwise poor candidates for MVD, neurosurgical options include percutaneous trigeminal rhizotomy and radiosurgery. Neurosurgical procedures are less effective in relieving atypical facial pain. In the clinical evaluation of a patient with facial pain, it is important to distinguish classic trigeminal neuralgia from atypical facial pain. A patient with classic trigeminal neuralgia would benefit from neurosurgical consultation. The advent of high-resolution MRI and MRA sequences now allows a neurosurgeon to detect when neurovascular compression is likely, and select the optimal procedure for treatment.

Efficacy and Prognostic Value of Partial Sensory Rhizotomy and Microvascular Decompression for Primary Trigeminal Neuralgia: A Comparative Study

Background

This study aimed to compare the efficacy and prognostic value of partial sensory rhizotomy (PSR) and microvascular decompression (MVD) for primary trigeminal neuralgia (PTN).

Material/Methods

From June 2010 to June 2012, 117 patients with PTN were recruited for the study, of which 52 cases were treated with MVD (the MVD group) and 65 cases were treated with PSR (the PSR group). Visual Analog Scoring (VAS) was performed at 1 and 2 weeks, and at 1, 3, and 6 month after surgery. The overall response rate (ORR) was determined 1 month after surgery. Barrow Neurological Institute score was adopted to value the reoccurrence at 6, 12, 24, and 36 months after surgery. A 3-year follow-up was conducted and the complications were recorded.

Results

The ORR 2 weeks after surgery in the MVD and PSR groups was 98.08% and 84.62%, respectively. One and 2 weeks after surgery, the VAS was lower in the MVD group than in the PSR group, but there was no significant difference in VAS between the 2 groups at 1, 3, and 6 months after surgery. Three years after surgery, the recurrence rate was significantly lower in the MVD group than in the PSR group. The recurrence-free survival time was longer in the MVD group than in the PSR group. The occurrence rates of herpes and total postoperative complications were significantly higher in the PSR group than in the MVD group.

Conclusions

Compared with PSR, MVD is more suitable for PTN treatment, with less disturbance, lower recurrence rate, and better efficacy.