Microvascular Decompression Technique for Trigeminal Neuralgia Using a Vascular Clip.

Microvascular decompression (MVD) surgery is a well-established, effective treatment option for trigeminal neuralgia1 and hemifacial spasm.2 In 1967, Janetta et al3 introduced the concept of MVD surgery and pioneered the Janetta technique in which Teflon felt implants are placed between the trigeminal nerve and offending vessel. Though many cases are successfully managed with Teflon interposition, alternative techniques have been developed with the objective to alleviate vascular compression symptoms indefinitely, including transposition using biological glue,4 vascular clips,5,6 and a variety of "sling" techniques.7 In Video 1, we demonstrate a fenestrated clip transposition technique in the treatment of trigeminal neuralgia. We present the case of a 72-year-old female who presented with classic trigeminal neuralgia pain along the V2 and V3 distributions. Magnetic resonance imaging revealed evident compression of the trigeminal nerve by the superior cerebellar artery (SCA). A retrosigmoid craniotomy was performed, and the vascular loop of the SCA was visualized compressing the root entry zone with significant indentation of the trigeminal nerve. Wide arachnoid dissection along the SCA was carried out in order to mobilize the SCA away from the nerve. A small slit was created in the undersurface of the tentorium, and then the SCA loop was transposed to the tentorium using a fenestrated aneurysm clip. The postoperative course was uneventful, and the patient had complete resolution of her facial pain at 6-month follow-up. This method is likely an effective and durable method of decompression for trigeminal neuralgia.

An Easy Adjustable Sling Technique of Ectatic Vertebral Artery Transposition for Microvascular Decompression.

Hemifacial spasm caused by an elongated, tortuous, or enlarged vertebral artery (VA) can be difficult to treat. Greater rates of incomplete cure also have been noted.1-6 In this video, we demonstrate the key steps of a simple and effective adjustable sling technique of an ectatic VA transposition for microvascular decompression. In this patient, an ectatic VA was stacked on the posterior inferior cerebellar artery, and together they compressed the root exit zone (REZ) of the facial nerve. We cut a suturable and unabsorbable artificial dural graft into a sling. The rougher side of the sling was used to wrap around the VA to obtain more friction and avoid sliding. Suitable width of the sling was determined to prevent prominent indentation on the VA. We wrapped the VA at a perforator-free zone and lifted the VA away from the REZ by pulling the sling in a lateral direction. At the same time, the anchor point for the aneurysm clip to hold the sling at the lateral skull base also was determined. We made a small dural incision at the anchor point, where an aneurysm clip was applied to hold the sling securely under tension but not to cause kinking of the VA/posterior inferior cerebellar artery. The patient had no hemifacial spasm immediately after the operation and thereafter. This adjustable sling technique provides an easy and strong hold to maintain an ectatic VA away from the REZ of the facial nerve (Video 1).

Teflon versus Ivalon in Microvascular Decompression for Trigeminal Neuralgia: A 2-Center 10-Year Comparison.

BACKGROUND: Trigeminal neuralgia features jolts of pain along the distribution of the trigeminal nerve. If patients fail conservative management, microvascular decompression (MVD) is typically the next step in treatment. MVD consists of implanting a separating material, often Teflon, between the nerve and compressive lesions. A review found similar success and complication rates between Teflon and Ivalon, another commonly used material. The aim of this study was to analyze outcomes and complications associated with Teflon and Ivalon in MVD. METHODS: We conducted a 2-center retrospective cohort study of trigeminal neuralgia treated with MVD between 2005 and 2019. Patients with no postoperative follow-up were excluded. Postoperative pain was graded using the Barrow Neurological Institute (BNI) pain intensity score. Relapse was defined as a BNI score of 4-5 during follow-up after initial pain improvement or an initial BNI score of 1-3. RESULTS: The study included 221 MVD procedures in 219 patients. Ivalon was implanted in 121 procedures, and Teflon was implanted in 100 procedures. Multivariate analysis found that implant type had no effect on final BNI score (P = 0.305). Relapse rates were similar at 5- and 10-year follow-up (5-year: Ivalon 10.7%, Teflon 18.0%, P = 0.112; 10-year: Ivalon 11.6%, Teflon 19.0%, P = 0.123). There was no difference in postoperative immediate facial numbness (P = 0.125). Postoperative hearing difficulty was higher in the Ivalon cohort (8.4% vs. 1.0%; P = 0.016). CONCLUSIONS: We found no significant difference in final BNI score or risk of relapse between Ivalon and Teflon. Complications were similar, although Ivalon was more associated with temporary postoperative hearing loss.

Microvascular Decompression of the Trigeminal Nerve with Petrous Sling Technique: Surgical Video.

The retrosigmoid approach for microvascular decompression of the trigeminal nerve (TN) is an established and highly effective technique for the treatment of trigeminal neuralgia due to vascular compression. It is common to place a pledget or other cushion material between the source of vascular compression, typically the superior cerebellar artery (SCA), and the TN after vessel mobilization and decompression. A previous study demonstrated the use of a tentorial sling on the SCA to maintain decompression of the TN, with encouraging results.1 In this video, we demonstrate a novel technique using a Gore-Tex (W. L. Gore & Associates, Newark, Delaware) sling wrapped around the SCA and secured with a vascular clip on the petrous dura to maintain decompression of the TN (Video 1). Informed consent was obtained from the patient. He tolerated the procedure well with excellent pain relief and was discharged on postoperative day 1.

Microvascular Decompression and Transposition of the 8th Cranial Nerve Using a Fenestrated Clip.

Neurovascular compression is a potential, yet rare cause of vertigo and unilateral tinnitus. Despite the high success rate of microvascular decompression (MVD) in other vascular compression syndromes, the outcome reported after MVD of the vestibulocochlear nerve is variable.1,2 The presence of combined symptoms of tinnitus and vertigo treated by MVD has demonstrated a higher predictive value for success.3 In this video, we present the case of a 68-year-old male who presented with vertigo and tinnitus refractory to medical management and vestibular therapy. Audiologic evaluation was normal apart from mild sensorineural hearing loss. Vestibular testing was suggestive of uncompensated right peripheral vestibulopathy. Magnetic resonance imaging with fast imaging employing steady-state acquisition sequences revealed vascular compression by the right anteroinferior cerebellar artery (AICA) at the cisternal component of vestibulocochlear nerve. After a multidisciplinary discussion, a microvascular decompression was performed through a right retrosigmoid craniotomy. The AICA was mobilized off the vestibulocochlear nerve and was secured to the petrous dura using a fenestrated clip. Indocyanine green angiography with Glow-800 was conducted before and after AICA transposition to confirm adequate flow through the mobilized vessel. Postoperatively, the patient's vestibular symptoms improved significantly. This case demonstrates that microvascular decompression can provide a satisfactory outcome in patients with unilateral tinnitus and vertigo associated with vascular compression in appropriately selected cases (Video 1).

Prosthesis Used in Microvascular Decompressions: A Multicenter Survey in Japan Focusing on Adverse Events.

OBJECTIVE: To investigate the characteristics of materials used as prostheses for microvascular decompression surgery (MVDs) in Japan and their possible adverse events (AEs) to determine preferable materials for MVDs. METHODS: A questionnaire was sent to all members of the Japanese Society for MVDs, and answers were obtained from 59 institutions. RESULTS: Among a total of 2789 MVDs, 1088 operations for trigeminal neuralgia, 1670 for hemifacial spasm, and 31 others, including 117 reoperations, were performed between April 2011 and March 2014. Nonabsorbable material was used in 96.5% of MVDs, including polytetrafluoroethylene (PTFE) (80.5%), polyurethane (11.9%), expanded PTFE (2.1%), and silk thread (1.47%). The use of absorbable materials, including fibrin glue (87.5%), cellulose (13.5%), gelatin (4,77%), and collagen (1.76%), was reported. The major combinations were PTFE with fibrin glue (58.7%) followed by PTFE alone (7.60%). Eighty-eight AEs in 85 (3.2%) cases were reported among 2672 first operations. AEs included 51 central nervous system dysfunctions, 15 wound infections/dehiscence, and 10 others, which were presumed to be related to the intraoperative procedure. Among relatively high-, moderate-, and low-volume centers, there were no significant differences in the frequency of AEs (P = 0.077). Tissue-prosthesis adhesion and/or granuloma formation were reported in 13 cases of 117 reoperations. The incidence of adhesion-related recurrence was 11.1% of all reoperations. CONCLUSIONS: The number of AEs was quite low in this survey, and intradural use of any prosthesis reported in this paper might be justified; however, further development of easily handled and less-adhesive prosthesis materials is awaited.

In vitro and in vivo experiments of a novel intra-arterial neurovascular decompressor for treating neurovascular compression syndromes: a brief report.

Objectives: Neurovascular compression syndromes (NVCS) could be cured with an intravascular device that releases compression of the root entry zone of cranial nerves by changing the course of offending vessels. The purpose of this study was to report our results of in vitro and in vivo experiments with a novel intra-arterial neurovascular decompressor (IA-NVD) for NVCS. Methods: A nitinol-based IA-NVD was developed to release pressure applied to the root entry zone of cranial nerves by changing the course or angle of an offending vessel, which can possibly cure NVCS. We performed in vitro tests for safety and feasibility and preliminary in vivo tests up to 4 weeks for safety. Results: The bending stiffness of the device was similar to but slightly stronger than that of current, closed-cell intracranial stents. Hemocompatibility tests showed no significant thrombogenesis in whole blood. After the 4-week follow-up, all animals (20-month-old female Gottingen mini-pigs weighing 15-18 kg, n = 4) had a normal upright position and gait. Scanning electron microscopy images and H&E staining of arteries containing the devices showed good neointima formation on the devices. Intima hyperplasia occurred over wires and connecting tubes, but it did not interrupt the patency of the arterial lumen. Discussion: An IA-NVD was created and tested to demonstrate its functionality and biocompatibility in the present experiments. The device may be safely applied to intracranial arteries, providing us a chance to test the efficacy of an upgrade version of the device on changing the course of an artery that compresses a cranial nerve. Abbreviations: CN = cranial nerve; EVT = endovascular treatment; H&E = hematoxylin and eosin; HFS = hemifacial spasm; IA-NVD = intra-arterial neurovascular decompressor; MVD = microvascular decompression; NVCS = neurovascular compression syndrome; REZ = root entry zone; SEM = scanning electron microscopy; TN = trigeminal neuralgia.

Microvascular Decompression for Trigeminal Neuralgia: A Durable, Noncompressive Technique Using Teflon Secured With Mini Clip.

BACKGROUND: In cases of trigeminal neuralgia, the importance of durable separation of involved vessels from the trigeminal nerve as well as avoiding ongoing or recurrent compression by implanted material has been affirmed in recent literature. OBJECTIVE: To demonstrate a novel and straightforward technique for trigeminal nerve decompression using a construct of Teflon felt patty (Bard Peripheral Vascular, Tempe, Arizona) secured with an aneurysm mini clip to achieve lasting results with no residual contact between implant or vessels and the nerve. METHODS: Description of our technique and accompanying surgical video. RESULTS: As demonstrated in the video, this technique achieves an ideal, durable separation of the trigeminal nerve from the offending vasculature. CONCLUSION: The authors present a description of a technique for decompression with the goal of leaving no contact between implanted material and the nerve. This is accomplished by securing the Teflon felt (Bard Peripheral Vascular) to the tentorium with an aneurysm clip.

A Meta-Analysis of Endoscopic Microvascular Decompression versus Microscopic Microvascular Decompression for the Treatment for Cranial Nerve Syndrome Caused by Vascular Compression.

OBJECTIVE: The aim of this study was to compare the efficacy and safety of endoscopic microvascular decompression (E-MVD) and microscopic microvascular decompression (M-MVD) for the treatment for cranial nerve syndrome caused by vascular compression, including primary trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia. METHODS: A systematic search of the online databases, including PubMed, Embase, Web of Science, Cochrane Central Register of Controlled Trials, China Biology Medicine disc, and China National Knowledge Infrastructure, was performed from January 1966 to March 2018. The language of the included literature was not limited. Relevant outcomes of perioperative safety and postoperative efficacy were considered for meta-analysis. Single-arm and cumulative meta-analyses were also conducted. All the outcomes were calculated as odds ratios (ORs) with 95% confidence intervals using R language. RESULTS: A total of 9 studies involving 1093 (E-MVD [543] vs. M-MVD [550]) patients were included for analysis in our study. The recent remission rate (92% vs. 86%; OR, 1.71; P = 0.0089), offending vessel discovery rate (99% vs. 95%; OR 2.76, P = 0.0061), and long-term remission rate (97% vs. 87%; OR 4.59, P = 0.0036) were significantly higher in patients who underwent E-MVD than in those who underwent M-MVD, whereas perioperative complications (23% vs. 35%; OR 0.56, P < 0.0001) were significantly lower in patients who underwent E-MVD. CONCLUSIONS: This meta-analysis confirms that E-MVD is superior to M-MVD both in perioperative and postoperative efficacy (short- and long-term), and therefore it should be considered as an appropriate treatment choice for patients with neuralgia and hemifacial spasm.

Pseudoaneurysm presenting around polytetrafluoroethylene fiber following microvascular decompression: A case report and literature review.

We report the first case of pseudoaneurysm associated with polytetrafluoroethylene fiber used in microvascular decompression (MVD). A 62-year-old female who had undergone MVD for hemifacial spasm 30 years ago presented with a 4-month history of progressive facial palsy. Computed tomography angiography revealed a large thrombosed aneurysm originating from the right posterior inferior cerebellar artery and having a mass effect upon the pons. The aneurysm was treated by trapping and bypass procedure. Intraoperatively, the pseudoaneurysm adhered to the dura mater, and the thrombus contained a large amount of polytetrafluoroethylene fiber. The cause and management of pseudoaneurysm after MVD is discussed.

Microvascular Decompression for Hemifacial Spasm Associated with Vertebral Artery: Biomedical Glue-Coated Teflon Sling Transposition Technique.

BACKGROUND: Microvascular decompression is the most effective treatment for hemifacial spasm. However, when encountering hemifacial spasm associated with vertebral artery (VA), the procedure is more challenging and requires complicated operation techniques. The authors retrospectively analyzed the clinical characteristics of this group of cases and investigated reasonable transposition procedures for different anatomic classifications. METHODS: We retrospectively analyzed 117 cases that underwent their first microvascular decompression for hemifacial spasm between June 2010 and December 2016, which had all associated with vertebral artery compression diagnosed by preoperational radiology examination. The study first classified offending vessels into 3 types according to operative anatomy and designed personalized decompression management according to different forms of neurovascular conflict. Curative effects and complications were assessed. RESULTS: The offending vessels were artificially divided into 3 types according to both arterial pattern and compression direction: 1) ipsilateral VA plus anterior inferior cerebellar artery compressing the facial nerve from the ventrolateral direction in 72 (61.5%) cases; 2) ipsilateral VA plus posterior inferior cerebellar artery compressing the facial nerve from the caudal-medial direction in 31 (26.5%) cases; 3) bilateral VA compressing the facial nerve in 14 (12.0%) cases. We selected corridors to expose the neurovascular conflict site between the suprafloccular-transhorizontal fissure approach and subtonsillar-transcerebellomedullary fissure approach. The methods of decompression consist of anteromedial and posterolateral transposition by using biomedical glue-coated Teflon sling. Sufficient decompression of the offending vessels was safely performed in all cases. All cases had total relief of symptoms immediately after their operations. Follow-up periods ranged from 16-90 months, and total recovery occurred in 110 cases (94.0%). In 7 cases (6.0%), 90% recovery occurred. CONCLUSIONS: Accuracy and comprehensive recognition of anatomic features of the offending vessels are crucial for the management of hemifacial spasm associated with vertebral artery compression. Appropriate approaches combined with the biomedical glue-coated Teflon sling transposition technique can allow adequate mobilization of the vertebral artery and bring complete postoperative symptom relief for most cases.

"Birdlime" technique using TachoSil tissue sealing sheet soaked with fibrin glue for sutureless vessel transposition in microvascular decompression: operative technique and nuances.

OBJECTIVE Microvascular decompression (MVD) is effective for the treatment of trigeminal neuralgia (TN), hemifacial spasm (HFS), and glossopharyngeal neuralgia. The transposition technique is the standard procedure to avoid adhesions and granuloma around the decompression site but is more complex and difficult to perform than the interposition technique. The authors describe a simple and safe MVD transposition procedure they call the "birdlime" technique, which uses a tissue glue-coated collagen sponge soaked with fibrin glue, and the results of this technique. METHODS The authors retrospectively reviewed the medical charts and radiographic findings of 27 consecutive patients with TN (8 patients) and HFS (19 patients) who, between January 2012 and December 2015, had undergone an MVD transposition procedure utilizing a tissue glue-coated collagen sponge (TachoSil tissue sealing sheet) soaked with fibrin glue (Tisseel 2-component fibrin sealant, vapor heated). Offending arteries among the patients with TN were the superior cerebellar artery (SCA) in 5 patients, the SCA and anterior inferior cerebellar artery (AICA) in 2, and the AICA in 1. Those among the patients with HFS were the vertebral artery (VA) in 3 patients, the VA and AICA in 4, the VA and posterior inferior cerebellar artery (PICA) in 3, the PICA in 4, the AICA in 1, the AICA-PICA in 3, and the PICA and AICA in 1. Operations were performed according to the Jannetta procedure. The offending artery was transposed and fixed to the dura mater of the petrous bone using TachoSil pieces soaked with fibrin glue. Postoperative constructive interference in steady-state MRI was performed to evaluate the change in the position of the offending artery. RESULTS Transposition of the offending artery was easily and safely performed in all patients. All patients had total remission of symptoms directly after the procedure. No severe complications occurred. The postoperative course was uneventful. No recurrences, adhesions, or dysfunction of the cranial nerves was observed in any of the patients. Postoperative MRI showed that the offending vessels were displaced and fixed in the appropriate position. CONCLUSIONS The described transposition technique provides an easy and adjustable way to perform MVD safely and effectively. In addition, this transposition and fixation technique is simple and avoids the risk of needle injury close to the cranial nerves and vessels. This simple sutureless technique is recommended for MVD to reduce the risk of intraoperative neurovascular injury.

Application of Ion-beam Implanted Expanded Polytetrafluoroethylene to Microvascular Decompression and the Surgical Outcome.

Accurate and long-term transposition of offending vessels is required in microvascular decompression (MVD) for the treatment of hemifacial spasm (HFS) and trigeminal neuralgia (TN). We created ion-beam implanted of an expanded-polytetrafluoroethylene (i-ePTFE) surface to transpose offending vessels in MVD. In 13 patients with MVD, we concealed and transposed offending vessels with tape-shaped i-ePTFE, and relieved facial and trigeminal nerve compression by attaching the i-ePTFE to the dura with fibrin glue. After surgery, none of the patients reported further symptoms or experienced recurrence of symptoms up to 12 months post-surgery. Favorable surgical outcomes are obtainable, since i-ePTFE has high tissue affinity and is easy to manipulate, even under a narrow and deep operative field. Our results suggested that i-ePTFE is very useful for transposition in MVD.

Microvascular Decompression for Trigeminal Neuralgia Using a Novel Fenestrated Clip and Tentorial Flap Technique.

BACKGROUND: Microvascular decompression (MVD) for neurovascular compression syndromes, such as trigeminal neuralgia and hemifacial spasm, has been traditionally described as an interposing technique using Teflon. Some alternative interposing materials have been proposed. In addition, transposing techniques have been increasingly reported as an alternative with a potentially lower recurrence rate and fewer complications. OBJECTIVE: To describe our experience with a technique consisting of transposition of the superior cerebellar artery using a fenestrated clip and a tentorial flap in patients with trigeminal neuralgia. METHODS: We describe a novel transposing technique using a fenestrated clip and a tentorial flap in patients with neurovascular compression. An illustrative case is provided of an 83-year-old female patient who complained of a 4-year history of left trigeminal neuralgia caused by compression by the superior cerebellar artery who was treated with this technique. Furthermore, a thorough review of the literature is presented. RESULTS: The patient underwent the procedure with the proposed technique without complication. Both the surgery and the postoperative course were uneventful. The patient remains asymptomatic 1 year after the procedure. CONCLUSION: We propose a novel technique for the treatment of trigeminal neuralgia, eliminating the need for padding the vessel with a foreign body. This technique can be applied successfully in selected cases of neurovascular compression syndromes.

The Multiscope Technique for Microvascular Decompression.

BACKGROUND: Endoscopic surgery has rapidly become widespread in neurosurgery in recent years. Endoscopy can offer close and panoramic surgical views with fine illumination, even in the deep intracranial area. However, it also has the following serious drawback: an intracranial blind area between the field lens of the endoscope and the site of the dural opening. This blind area cannot be viewed on the endoscopic monitor, and several surgical complications, including accidental intracranial neurovascular structural injury, can occur in this area. In this article, we report a new multiscope surgical technique that can compensate for this serious disadvantage of endoscopic surgery. METHODS: In the multiscope technique, endoscopic and exoscopic systems are used simultaneously with 2 monitors. Microvascular decompression (MVD) is performed fully endoscopically using an exoscope that compensates for the intracranial blind area of the endoscopic view. Two high-definition monitors for the endoscope and exoscope are placed side-by-side in front of the primary surgeon. RESULTS: Two patients with hemifacial spasm were treated by endoscopic MVD with the multiscope technique. In these procedures, fine surgical views were obtained by both the endoscope and exoscope. Two monitors were placed side-by-side in front of the surgeon; as a result, the physician could easily view them simultaneously during the operation. No surgery-related complications occurred. CONCLUSIONS: The multiscope technique can facilitate the performance of safer neuroendoscopic surgery than conventional endoscopic surgery. This technique can also be adopted in other skull base surgeries, in which the importance of endoscopy is growing.

Teflon Might Be a Factor Accounting for a Failed Microvascular Decompression in Hemifacial Spasm: A Technical Note.

BACKGROUND: Although Teflon is widely adopted for microvascular decompression (MVD) surgery, it has never been addressed for failure analysis. This study analyzed the reasons for failed MVDs with emphasis on the Teflon sponge. METHODS: Among the 685 hemifacial spasm cases between 2010 and 2014, 31 were reoperated on within a week because of unsatisfactory outcome, which was focused on in this study. Intraoperative findings regarding Teflon inserts of these repeat MVDs were reviewed. RESULTS: Among the 38 without satisfactory outcomes, 31 underwent repeat MVDs, and they were all spasm free afterwards. Eventually, the final cure rate was 99.2%. It was found in the repeat MVDs that the failure was attributable to the Teflon insert in most of the cases (74.2%) directly or indirectly. It was caused by improper placement (47.8%), inappropriate size (34.8%) and unsuitable shape (17.4%) of the Teflon sponge. CONCLUSION: Although it is not difficult for an experienced neurosurgeon to discover a neurovascular conflict during the MVD process, the size, shape and location of the Teflon sponge should not be ignored. Basically, the Teflon insert is used to keep the offending artery away from the facial nerve root rather than to isolate it. Therefore, the ideal Teflon sponge should be just small enough to produce a neurovascular separation.

Hemifacial spasm caused by a cerebellopontine angle arachnoid cyst. Case report and literature review / Espasmo hemifacial causado por un quiste aracnoideo del ángulo pontocerebeloso. Caso clínico y revisión de la literatura

Arachnoid cysts involving the cerebellopontine angle are an unusual cause of hemifacial spasm. The case is reported of a 71-year old woman presenting with a right hemifacial spasm and an ipsilateral arachnoid cyst. Preoperative magnetic resonance imaging findings suggested a neurovascular compression caused by displacement of the facial-acoustic complex and the anterior inferior cerebellar artery by the cyst. Cyst excision and microvascular decompression of the facial nerve achieved permanent relief. The existing cases of arachnoid cysts causing hemifacial spasm are reviewed and the importance of a secondary neurovascular conflict identification and decompression in these cases is highlighted

Los quistes aracnoideos del ángulo pontocerebeloso son una causa inusual de espasmo hemifacial. Describimos el caso de una mujer de 71 años que presentaba un espasmo hemifacial derecho y un quiste aracnoideo ipsilateral. Los hallazgos de la resonancia magnética preoperatoria indicaban una compresión neurovascular provocada por el desplazamiento del complejo nervioso facial-acústico y de la arteria cerebelosa anteroinferior por el quiste. La extirpación del quiste y la descompresión microvascular del nervio facial consiguieron un alivio permanente del espasmo. Se revisan los casos conocidos de espasmo hemifacial secundario a un quiste aracnoideo y se resalta la importancia de identificar un conflicto neurovascular secundario y de realizar una descompresión en estos casos

Trigeminal Neuralgia: Evaluation of the Relationship Between the Region of Neuralgic Manifestation and the Site of Neurovascular Compression Under Endoscopy.

This study aimed to evaluate the relationship among the pain region, branches of trigeminal nerve, and the neurovascular compression (NVC) location. A total of 123 consecutive patients with trigeminal neuralgia (TN) underwent endoscope-assisted microvascular decompression according to positive preoperative tomographic angiography. V2 alone was in 51 cases and V3 alone was in 64 cases. The location of NVC was classified into cranial, caudal, medial, or lateral sites. Some patients with multiple regions were recorded as medial + cranial, lateral + cranial, medial + caudal, and lateral + caudal. Twenty-eight (71.8%) of 39 patients with TN (V2) had their NVC at the medial site of the nerve. Twenty-seven (64.3%) of 42 patients with TN (V3) had their NVC at the lateral site of the nerve. There was a statistically significant difference (P = 0.0011 < 0.01, χ2 test). Sixteen (69.6%) of 23 patients with TN(V2) had their NVC at the cranial site of the nerve. Thirty-four (69.4%) of 49 patients with TN (V3) had their NVC at the caudal site of the nerve. There was no statistical difference (P = 0.3097 > 0.01). Evaluation of the relationship between the pain region and the NVC location by endoscopic images during microvascular decompression is more accurate. The second branch is mostly distributed in the medial area, and third branch is mainly distributed in the lateral area.

Long-term effectiveness of an ad hoc tailored titanium implant as a spacer for microvascular decompression in the treatment of trigeminal neuralgia caused by megadolichoectatic basilar artery anomaly: 9-year follow-up.

An enlarged, elongated, ectatic, and sclerotic aberration of the vertebrobasilar system is known as a megadolichoectatic basilar artery (BA) anomaly. The anomaly is often involved in the pathological process of trigeminal neuralgia by compressing and distorting the trigeminal nerve. First-line medical treatment includes drug therapy, but a second-line surgical procedure could be effective in medication-resistant cases. The authors report the case of a 65-year-old man with a 12-year history of progressing trigeminal neuralgia who underwent microvascular decompression after the first-line drug treatment had failed. This case is unique because an in situ tailored titanium microplate was used as a spacer to alleviate compression by the BA on the trigeminal nerve. The titanium implant provided durable and sufficient retraction for the sclerotic arterial complex when the trigeminal nerve was placed in the tunnel of the implant. The 9-year follow-up examination proves the safety and long-term efficacy of titanium implants in the treatment of trigeminal neuralgia caused by a megadolichoectatic BA anomaly. The method applied in this case was not intended to be and certainly is not an alternative to routine microvascular decompression-this surgical solution may be reserved for some extreme cases.

Usefulness of the endoscope in microvascular decompression for trigeminal neuralgia and MRI-based prediction of the need for endoscopy.

BACKGROUND: Microvascular decompression (MVD) is a documented effective treatment of trigeminal neuralgia (TN). Lately, reports on endoscopy-assisted microvascular decompression (eaMVD) with better outcome and less risk have emerged. This study was undertaken to verify under which circumstances the endoscope proved essential in identifying the neurovascular conflict (NVC) during eaMVD for TN, and to assess the possibility to predict the need for the endoscope on preoperative magnetic resonance imaging (MRI). METHODS: Retrospective analysis of 97 patients with TN undergoing eaMVD at the Oslo University Hospital - Rikshospitalet, 1999-2009. To assess the NVC and anatomical variations, surgical reports were evaluated. MRI was available in 66 patients. The MRIs were evaluated by a blinded neuroradiologist. RESULTS: In 27 of the 97 patients (27.8 %), the endoscope was a significant aid in identifying the NVC, due to a bony ridge obscuring the view of the fifth nerve, a very distal vascular compression, or a combination of both. The preoperative MRI over-diagnosed the presence of a bony ridge. However, the MRI-based fraction of microscopically visible trigeminal nerve (FVN) in the cerebellopontine angle cistern proved diagnostic (ROC curve, AUC 0.89, p = <0.001) with an optimal cut-off value of 0.35. Hence, if less than 35 % of the trigeminal nerve is visible on preoperative MRI, the endoscope will be needed to identify the NVC. CONCLUSIONS: The endoscope is a valuable tool during MVD for TN, especially under anatomical circumstances such as a bony ridge hiding the direct microscopic view of the NVC. These anatomical circumstances can be predicted with good accuracy on preoperative MRI.