Trigeminal Root Research Articles

Нейроваскулярный конфликт с компрессией двигательной порции тройничного нерва: гемимастикаторный спазм и синдром Парри — Ромберга. Клиническое наблюдение

The most common cause of neurovascular conflict (NVC) is the compression of the sensory portion of the trigeminal nerve root by artery or vein directly at the brainstem. This results in local demyelination manifested as the classic trigeminal neuralgia. The motor portion of the trigeminal nerve is affected less commonly. The authors describe a case history of a 26-year-old man with a verified NVC of the motor portion of the trigeminal nerve. At the onset, the disease manifested as intense pain paroxysms in the left side of the face preceded by a masseter muscle spasm that was accompanied by lockjaw and tongue biting (hemimasticatory spasm). Shortly after disease onset, facial hemiatrophy with local scleroderma developed. The diagnosis of NVC with the compression of the motor portion of the trigeminal nerve accompanied by hemimasticatory spasm and Parry-Romberg syndrome was verified by brain FIESTA MRI and needle EMG. Later on, these symptoms spontaneously regressed. Concepts of hemimasticatory spasm and facial hemiatrophy are discussed. The rarity of this condition, lack of information on the compression of the motor portion of the trigeminal nerve in NVC, unusual disease onset, and presentations make this issue interesting for a wide range of experts. KEYWORDS: neurovascular conflict, hemimasticatory spasm, facial hemiatrophy, Parry-Romberg syndrome, trigeminal neuralgia, trigeminal nerve, local scleroderma, oromandibular dystonia. FOR CITATION: Matveeva T.V., Kazantsev A.Yu., Aleskerova A.B., Gaifutdinov R.T. Neurovascular conflict with the compression of the motor portion of the trigeminal nerve: hemimasticatory spasm and Parry-Romberg syndrome. Case report. Russian Medical Inquiry. 2021;5(10):668–673 (in Russ.). DOI: 10.32364/2587-6821-2021-5-10-668-673.

Five-year result of Microvascular decompression using video endoscopy in the treatment of classic trigeminal neuralgia with paroxysmal pain syndrome

Background. The incidence of trigeminal neuralgia (TN) is 15 per 100,000 people per year. The effectiveness of the existing conservative methods of therapy does not exceed 50%. At the same time, the use of carbamazepine doubles the frequency of depressive conditions, and by 40% increases the incidence of suicidal thoughts. Microvascular decompression (MVD) of the trigeminal root is a"gold standard" treatment for patients with facial pain, however, due to the lack of awareness of the disease, not all the patients receive the adequate therapy timely. Aims: to evaluate the long-term results of video endoscopy-assisted microvascular decompression in the treatment of patients with classical trigeminal neuralgia (cNTN) with paroxysmal facial pain. Methods. In the period from 2014 to 2019, 62 patients were operated for classic NTN and paroxysmal facial pain. The average period from the onset of pain syndrome to surgery was 5 years (from 2 months to 15 years). All the patients in the preoperative period underwent conservative therapy (carbamazepine, gabapentin, pregabalin), which was not accompanied by significant pain reduction. Two (3%) patients had previously undergone a radiosurgical treatment using the Gamma Knife device, and 7 (11%) patients had an analgesic blockade without an effect at other hospitals. The maximum pain intensity upon the admission to the hospital, according to the visual analogue scale (VAS,) was 10 points, according to the BNI (Barrow Neurological Institute) pain syndrome scale V. All the patients underwent MVD of the trigeminal nerve root using Teflon, and video endoscopic assistance during surgery was used in 9 patients . The average follow-up period after the surgery was 3.4 1.7 years (from 1 to 5 years). Results. In all (100%) the patients, the pain was completely relieved after the surgery (BNI I). Excellent and good results after MVD within 5 years were achieved in 97% of patients (BNI III). Facial hypesthesia, not causing discomfort and anxiety (BNI II), developed in 5 (8.1%) patients. The use of video endoscopy made it possible to identify the vessels compressing the trigeminal nerve root with a minimal traction of the cerebellum and cranial nerves. The development of cerebellar edema and ischemia occurred in one (1.6%) patient operated without the application of video endoscopy. Conclusion. The MVD method with video endoscopy is effective in the treatment of patients with cNTN with paroxysmal pain syndrome.

Basilar artery dolichoectasia an unusual and rare cause of secondary trigeminal neuralgia: a clinical report

Objective: Patients with Trigeminal Neuralgia often consults a dentist for relief of their symptoms as the pain seems to be arising from teeth and allied oral structures. Basilar artery Dolichoectasia is an unusual and very rare cause of secondary Trigeminal Neuralgia as it compresses the Trigeminal nerve Root Entry Zone. Case reports: We report three cases of Trigeminal Neuralgia caused by Basilar artery Dolichoectasia compression. The corneal reflex was found absent in all three of the cases along with mild neurological deficits in one case. Multiplanar T1/T2W images through the brain disclosed an aberrant, cirsoid (S-shaped) and torturous Dolichoectasia of basilar artery offending the Trigeminal nerve Root Entry Zone. Discussion: Based on these findings we propose a protocol for general dentist for diagnosis of patients with trigeminal neuralgia and timely exclusion of secondary intracranial causes. Conclusion: General dentists and oral surgeons ought to consider this diagnosis in patients presenting with chronic facial pain especially pain mimicking neuralgia with loss of corneal reflex or other neurosensory deficit on the face along with nighttime pain episodes. Timely and accurate diagnosis and prompt referral to a concerned specialist can have an enormous impact on patient survival rate in such cases. KEYWORDS Basilar artery; Cirsoid dolichoectasia; Corneal reflex; Trigeminal neuralgia.

Trigeminal neurovascular contact in SUNCT and SUNA: a cross-sectional magnetic resonance study.

Emerging data-points towards a possible aetiological and therapeutic relevance of trigeminal neurovascular contact in short lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and perhaps in short lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (SUNA). We aimed to assess the prevalence and significance of trigeminal neurovascular contact in a large cohort of consecutive SUNCT and SUNA patients and evaluate the radiological differences between them. The standard imaging protocol included high spatial and nerve-cistern contrast resolution imaging acquisitions of the cisternal segments of the trigeminal nerves and vessels. MRI studies were evaluated blindly by two expert evaluators and graded according to the presence, location and degree of neurovascular contact. The degree of contact was graded as with or without morphological changes. Neurovascular contact with morphological changes was defined as contact with distortion and/or atrophy. A total of 159 patients (SUNCT = 80; SUNA = 79) were included. A total of 165 symptomatic and 153 asymptomatic trigeminal nerves were analysed. The proportion of neurovascular contact on the symptomatic trigeminal nerves was higher (80.0%) compared to the asymptomatic trigeminal nerves (56.9%). The odds on having neurovascular contact over the symptomatic nerves was significantly higher than on the asymptomatic nerves [odds ratio (OR): 3.03, 95% confidence interval (CI) 1.84-4.99; P < 0.0001]. Neurovascular contact with morphological changes were considerably more prevalent on the symptomatic side (61.4%), compared to the asymptomatic side (31.0%) (OR 4.16, 95% CI 2.46-7.05; P < 0.0001). On symptomatic nerves, neurovascular contact with morphological changes was caused by an artery in 95.0% (n = 77/81). Moreover, the site of contact and the point of contact around the trigeminal root were respectively proximal in 82.7% (67/81) and superior in 59.3% (48/81). No significant radiological differences emerged between SUNCT and SUNA. The multivariate analysis of radiological predictors associated with the symptomatic side, indicated that the presence of neurovascular contact with morphological changes was strongly associated with the side of the pain (OR: 2.80, 95% CI 1.44-5.44; P = 0.002) even when adjusted for diagnoses. Our findings suggest that neurovascular contact with morphological changes is involved in the aetiology of SUNCT and SUNA. Along with a similar clinical phenotype, SUNCT and SUNA also display a similar structural neuroimaging profile, providing further support for the concept that the separation between them should be abandoned. Furthermore, these findings suggest that vascular compression of the trigeminal sensory root, may be a common aetiological factor between SUNCT, SUNA and trigeminal neuralgia thereby further expanding the overlap between these disorders.

Co-culture methods to study neuronal function and disease.

Co-culture methods to study neuronal function and disease.

Microvascular decompression for trigeminal neuralgia caused by trigeminocerebellar artery.

In this operative video, the authors demonstrate the case of a 53-year-old woman who presented with typical right trigeminal neuralgia by a trigeminocerebellar artery (TCA). The TCA was first defined by Marinković as a unique branch of the basilar artery supplying both the trigeminal nerve root and the cerebellar hemisphere. As a result of the close relationship between this vessel and the nerve root, the TCA might compress the nerve root, thereby causing trigeminal neuralgia. However, few cases of trigeminal neuralgia caused by TCA have been reported. This video shows the microvascular decompression for trigeminal neuralgia by the TCA.The video can be found here: https://youtu.be/UnGsCQRK6aY

Surgical Management of the Trigeminocerebellar Artery in Microvascular Decompression for Trigeminal Neuralgia.

The trigeminocerebellar artery (TCA) is a variant branch of the basilar artery supplying the trigeminal nerve root and cerebellar hemisphere, which may contribute to trigeminal neuralgia (TGN). Despite its unique anatomic description, information regarding the preoperative diagnosis and surgical management of TCA is lacking. To evaluate our preoperative diagnosis of TCA using 3-dimensional (3D) images and surgical management of TGN cases with TCA involvement. We reviewed our 15 patients with TCA involvement (3.3%) among 460 consecutive patients undergoing microvascular decompression for TGN. In this study, all patients were examined using 3D images using GammaPlan (Elekta, Stockholm, Sweden). TCAs were divided into 2 groups based on surgical findings: encircling type and intraneural type. Biographical data, radiological findings, and operative video recordings were reviewed retrospectively. Surgical outcomes and follow-up were assessed and compared between the 2 groups. TCA involvement was confirmed preoperatively in 14 of the 15 patients using 3D images. All patients were operated with our unique transposition technique and became pain free immediately after the surgery. Pain-free status was maintained during the follow-up period (3.5±2.6 yr) in all patients but one in whom pain recurred 4 yr after the initial surgery. Re-exploration revealed an adhesion between the Teflon felt and the nerve root. Although TCA involvement is rare, an accurate preoperative diagnosis is essential because the decompression technique may differ from those used for other common cases. Scrutinizing anatomically rare variation with 3D images is recommended for predicting TCA involvement.

Mapping the trigeminal root entry zone and its pontine fibre distribution patterns.

IntroductionRecently, an additional trigeminothalamic tract – the dorsal trigeminothalamic tract – has been described in human brainstems by our group next to the known ventral trigeminothalamic tract. As various elements of the trigeminal system are known to be organised in a somatotopic fashion, the question arose whether the fibres within the trigeminal root show specific distributions patterns in their contribution to the ventral trigeminothalamic tract and dorsal trigeminothalamic tract specifically.MethodsThis study investigated the arrangement of the fibres in the trigeminal root by combining various imaging methods in the pons of 11 post-mortem specimens. The pons were investigated by polarised light imaging (PLI) (n = 4; to quantify fibre orientation; 100 µm interslice distance), histochemical staining methods (n = 3; to visualise the internal myeloarchitecture; 60 µm) and ultra-high field, post-mortem magnetic resonance imaging (MRI) (n = 4; for tractography; 500 µm interslice distance).ResultsThis study shows that the fibres, from the point where the trigeminal root enters the brainstem, are distinctly arranged by their contribution to the ventral trigeminothalamic tract and dorsal trigeminothalamic tract. This finding is supported by both post-mortem, ultra-high dMRI and different light microscopy techniques.ConclusionThe data from this study suggest that the fibres in the superior half of the root contribute mainly to the ventral trigeminothalamic tract, whereas the fibres in the inferior half mainly contribute to the dorsal trigeminothalamic tract. Such a somatotopic organisation could possibly create new insights into the anatomical origin of trigeminal neuralgia and the clinical relevance of this somatotopic organisation should therefore be further explored.

Endoscopic transcanal transpetrosal approach to the petroclival region: a cadaveric study with comparison to the Kawase approach.

This study introduces expanded application of the endoscopic transcanal approach with anterior petrosectomy (ETAP) in reaching the petroclival region, which was compared through a quantitative analysis to the middle fossa transpetrosal-transtentorial approach (Kawase approach). Anatomical dissections were performed in five cadaveric heads. For each head, the ETAP was performed on one side with a detailed description of each step, while the Kawase approach was performed on the contralateral side. Quantitative measurements of the exposed area over the ventrolateral surface of the brainstem, and of the angles of attack to the posterior margin of the trigeminal nerve root entry zone (CN V-REZ) and porus acusticus internus (PAI) were obtained for statistical comparison. The ETAP provided significantly larger exposure over the ventrolateral surface of the pons (93.03 ± 21.87mm2) than did the Kawase approach (34.57 ± 11.78mm2). In contrast to the ETAP, the Kawase approach afforded greater angles of attack to the CN V-REZ and PAI in the vertical and horizontal planes. The ETAP is a feasible and minimally invasive procedure for accessing the petroclival region. In comparison to the Kawase approach, the ETAP allows for fully anterior petrosectomy and larger exposure over the ventrolateral surface of the brainstem without passing through the cranial nerves or requiring traction of the temporal lobe.

Refractory Trigeminal Neuralgia: Successful Treatment with LINAC Based Stereotactic Radiosurgery (SRS): First Case in Bangladesh

Purpose: To present first case of refractory trigeminal Neuralgia treated with SRS in Bangladesh, procedural technique, and outcomes in terms of pain relief. Background: Trigeminal neuralgia (TN), classically known as tic doloureaux is a chronic and recurrent disabling pain syndrome, which described as episodes of lancinating pain over the face along the sensory distribution of trigeminal nerve. First line management of TN is medical with different permutation &amp; combination to control the pain. After the failure of medical management, non-invasive SRS is an established modality to achieve long term pain control. Here, we are reporting a case of TN treated with LINAC based SRS. Case Presentation: A 61 years old, gentleman who developed piercing pain inside his left eye for a duration 1-1.5 sec, precipitated while shaving, brushing teeth in year 2015, occurred 4-5 time a day. He was diagnosed as left TN of V1, started on Carbamazepine, Pregabalin. In 3 years, pain progressed to involve all 3 branches. Even combination Carbamazepine, Gabapentin, Tramadol, Amitriptyline, Clonazepam, &amp; Morphine could not control the pain. Pain was persisting all over the day and he also developed suicidal tendency. Later he has been referred to us for SRS. SRS was done in April-2019, a dose of 90Gy was delivered to the Distal Retrogasserian (RG) also called Marseille point of trigeminal nerve root. Eight months after the SRS patient is almost free of pain without any Medicine. Conclusions: LINAC based SRS is a non-invasive, frameless, and safe procedure with excellent pain control for refractory Trigeminal neuralgia. Bang. J Neurosurgery 2020; 10(1): 123-129

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

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. 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. 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 8years after surgery. Postoperative facial numbness was observed in six patients (23%). Of these, one patient showed improvement within 3months 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 (< 50db), 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. 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.

A reformed “release hypothesis” for Marcus Gunn Syndrome, based on newer clinic observations and experimental evidences

Marcus Gunn Syndrome (MGS), mostly occurring in congenital ptosis patients, is characterized by jaw movement evoking ptotic eyelid retraction, followed by collapse. Inverted, bilateral and acquired MGS were also reported. Some cases manifest MGS only temporarily in life. These features suggest MGS may be due to multiple pathogeneses, which are still unclear. People also classify MGS as a kind of trigeminal oculomotor synkenesis (TOS), like Duane syndrome (DS), in which ocular adduction prompts eyelid moving or eyeball retraction. The most popular hypothesis for TOS is congenital miswiring, as evidence supporting this hypothesis is found in DS cases: hypoplasia abducens nerve fusing with a branch of oculomotor nerve is observed. Seven mutant genes have been identified associated with TOS and two of them are found among MGS cases. Accordingly, these mutant genes may dominate cranial nerve misconnection and generate TOS. However, unlike in DS case, evidence of miswiring is not encountered in most MGS cases. The fact is that two “MGS genes” are from congenital fibrosis of extraocular muscle (CFEOM) cases presenting with associated MGS. But most of MGS cases do not suffer CFEOM. Thus, mutant genes dominated congenital miswiring may not be the pathogenesis for the majority of MGS. As an alternate pathogenic pathway, a “release hypothesis” proposed that MGS is a primitive physiologic reflex that became suppressed during phylogenetic development but could be released under certain pathologic conditions. This hypothesis was and is overlooked because the hypothesized reflex arc has not been defined. Decades ago, a neural tract tracing study in Xenopus revealed a direct projection from masticator afferent mesencephalic trigeminal nucleus (Vme) neurons to oculomotor and trochlear nucleus (III/IV). In clinical studies, co-firing of pterygoid muscle and levator palpebrae was recorded by electromyography during onset of MGS, and stimulating pterygoid muscle nerve elicited eyelid retraction. Recently, retraction of the ipsilateral eyelid by stimulating the trigeminal motor root was even observed in cases without congenital ptosis and MGS, highlighting the existence of a latent pathway. In rats, recently we demonstrated projections from the Vme neurons to the III/IV, and to their premotor neurons in interstitial nucleus of Cajal by neural tract tracing and electrophysiologic studies. Fos expression in pre-oculomotor neurons was induced by repeated down stretching the lower jaw. Combining previous and our own studies, we assumed the Vme neurons is excited when jaw moves and in turn, some eyelid activity related III motoneurons are activated through projections of Vme to oculomotor system, like in Xenopus. Genetic factors may dominate to what extent this primitive reflex-arc is preserved, which consequently determines phenotype.

Highly functionalized \u03b2-lactams and 2-ketopiperazines as TRPM8 antagonists with antiallodynic activity

The cool sensor transient receptor potential melastatin channel 8 (TRPM8) is highly expressed in trigeminal and dorsal root ganglia, playing a key role in cold hypersensitivity associated to different peripheral neuropathies. Moreover, these channels are aberrantly expressed in different cancers, and seem to participate in tumor progression, survival and invasion. Accordingly, the search for potent and selective TRPM8 modulators attracted great interest in recent years. We describe new heterocyclic TRPM8 antagonist chemotypes derived from N-cloroalkyl phenylalaninol-Phe conjugates. The cyclization of these conjugates afforded highly substituted β-lactams and/or 2-ketopiperazine (KP) derivatives, with regioselectivity depending on the N-chloroalkyl group and the configuration. These derivatives behave as TRPM8 antagonists in the Ca2+ microfluorometry assay, and confirmed electrophysiologically for the best enantiopure β-lactams 24a and 29a (IC50, 1.4 and 0.8 µM). Two putative binding sites by the pore zone, different from those found for typical agonists and antagonists, were identified by in silico studies for both β-lactams and KPs. β-Lactams 24a and 29a display antitumor activity in different human tumor cell lines (micromolar potencies, A549, HT29, PSN1), but correlation with TRPM8 expression could not be established. Additionally, compound 24a significantly reduced cold allodynia in a mice model of oxaliplatin-induced peripheral neuropathy.

Concomitant continuous pain in patients with trigeminal neuralgia is associated with trigeminal nerve root atrophy.

Trigeminal neuralgia is an exemplary neuropathic pain condition characterized by paroxysmal electric-shock-like pain. However, up to 50% of patients also experiences concomitant continuous pain. In this neuroimaging study, we aimed to identify the specific anatomical features of trigeminal nerve root in patients with concomitant continuous pain. We enrolled 73 patients with a definitive diagnosis of classical and idiopathic trigeminal neuralgia and 40 healthy participants. The diagnosis of trigeminal neuralgia was independently confirmed by two clinicians. Patients were grouped as patients with purely paroxysmal pain (45 patients) and patients also with concomitant continuous pain (28 patients). All participants underwent a structured clinical examination and a 3T MRI with sequences dedicated to the anatomical study of the trigeminal nerve root, including volumetric study. Images analysis was independently performed by two investigators, blinded to any clinical data. In most patients with concomitant continuous pain, this type of pain, described as burning, throbbing or aching, manifested at the disease onset. Demographic and clinical variables did not differ between the two groups of patients; the frequency of neurovascular compression and nerve dislocation were similar. Conversely, trigeminal nerve root atrophy was more severe in patients with concomitant continuous pain than in those with purely paroxysmal pain (p = 0.006). Our clinical and neuroimaging study found that in patients with trigeminal neuralgia, concomitant continuous pain was associated with trigeminal nerve root atrophy, therefore suggesting that this type of pain is likely related to axonal loss and abnormal activity in denervated trigeminal second-order neurons.

Chemokine receptor CXCR7 non-cell-autonomously controls pontine neuronal migration and nucleus formation

Long distance tangential migration transports neurons from their birth places to distant destinations to be incorporated into neuronal circuits. How neuronal migration is guided during these long journeys is still not fully understood. We address this issue by studying the migration of pontine nucleus (PN) neurons in the mouse hindbrain. PN neurons migrate from the lower rhombic lip first anteriorly and then turn ventrally near the trigeminal ganglion root towards the anterior ventral hindbrain. Previously we showed that in mouse depleted of chemokine receptor CXCR4 or its ligand CXCL12, PN neurons make their anterior-to-ventral turn at posteriorized positions. However, the mechanism that spatiotemporally controls the anterior-to-ventral turning is still unclear. Furthermore, the role of CXCR7, the atypical receptor of CXCL12, in pontine migration has yet to be examined. Here, we find that the PN is elongated in Cxcr7 knockout due to a broadened anterior-to-ventral turning positions. Cxcr7 is not expressed in migrating PN neurons en route to their destinations, but is strongly expressed in the pial meninges. Neuroepithelium-specific knockout of Cxcr7 does not recapitulate the PN phenotype in Cxcr7 knockout, suggesting that CXCR7 acts non-cell-autonomously possibly from the pial meninges. We show further that CXCR7 regulates pontine migration by modulating CXCL12 protein levels.

In Reply: Vascular Transposition of the Superior Cerebellar Artery Using a Fenestrated Clip and Fibrin Glue in Trigeminal Neuralgia: 2-Dimensional Operative Video

This is the case of an 86-yr-old gentleman who presented with left facial pain exacerbated by eating, drinking, chewing, and shaving (distribution: V2, V3). The patient was diagnosed with trigeminal neuralgia and was refractory to medications. Imaging showed a superior cerebellar artery (SCA) loop adjacent to the trigeminal nerve root entry zone and a decision to perform a microvascular decompression of the fifth nerve was presented to the patient. After patient informed consent was obtained, a standard 3 cm × 3 cm retrosigmoid craniotomy was performed with the patient in a supine head turned position and in reverse Trendelenburg. The arachnoid bands tethering the SCA to the trigeminal nerve were sharply divided. A slit was then made in the tentorium and a 3 mm fenestrated clip was then used to secure the transposed SCA away from the trigeminal nerve. The SCA proximal to this was slightly patulous in its course so a small amount of a fibrin glue was also used to secure the more proximal SCA to the tentorium. The patient was symptom-free postoperatively and no longer required medical therapy. Additionally, imaging was consistent with adequate separation of the nerve from adjacent vessels.1-5.

Vascular Transposition of the Superior Cerebellar Artery Using a Fenestrated Clip and Fibrin Glue in Trigeminal Neuralgia: 2-Dimensional Operative Video

This is the case of an 86-yr-old gentleman who presented with left facial pain exacerbated by eating, drinking, chewing, and shaving (distribution: V2, V3). The patient was diagnosed with trigeminal neuralgia and was refractory to medications. Imaging showed a superior cerebellar artery (SCA) loop adjacent to the trigeminal nerve root entry zone and a decision to perform a microvascular decompression of the fifth nerve was presented to the patient. After patient informed consent was obtained, a standard 3cm × 3cm retrosigmoid craniotomy was performed with the patient in a supine head turned position and in reverse Trendelenburg. The arachnoid bands tethering the SCA to the trigeminal nerve were sharply divided. A slit was then made in the tentorium and a 3 mm fenestrated clip was then used to secure the transposed SCA away from the trigeminal nerve. The SCA proximal to this was slightly patulous in its course so a small amount of a fibrin glue was also used to secure the more proximal SCA to the tentorium. The patient was symptom-free postoperatively and no longer required medical therapy. Additionally, imaging was consistent with adequate separation of the nerve from adjacent vessels.1-5.

Surgical Treatment of Trigeminal Neuralgia Combined with Tumors of the Cerebellopontine Angle

Introduction . Trigeminal neuralgia (TN) develops because of demyelination in the entry zone of the trigeminal nerve root (TNR) into the brainstem, which is accompanied by ectopic and cross-excitation of the nerve impulses with paroxysms of facial pain. One of the causes of TN are tumors of the cerebellopontine angle (CPA), which have a direct or indirect effect on the TNR. The optimal surgical approach in such cases depends on the anatomical relationship between the TNR and the tumor and vascular structures. The aim of the study was to evaluate the relationship between the anatomical variants of the TNR and the outcomes of using various surgical methods to treat TN in CPA tumors. Materials and methods. We performed a retrospective analysis of 52 patients (38 women and 14 men aged 22–82 years) with TN and ipsilateral tumors of the CPA: 29 with apical petrous meningiomas, 11 with epidermoid tumors, 10 with vestibular schwannomas, 1 with haemangioma, and 1 with cavernoma. Results. Six variants of the anatomical relationships of the TNR to CPA tumors and the adjacent vascular structures were identified: where the TNR is completely surrounded by the tumor; where the tumor compresses and displaces the TNR; where the tumor is located inside the TNR; where the tumor, together with the blood vessel, compresses the TNR; where the tumor displaces the TNR towards the vessel; and where the tumor is not in contact with the TNR, but the TNR is compressed by the blood vessel. Displacement and deformation of the TNR by CPA tumors was found in 50 patients, and no direct contact between the TNR nerve fibers and the neoplasm was observed in 2 cases. The neurovascular conflict caused by arterial and venous vessels was identified in 16 subjects. The type of a vascular decompression technique depended on the degree of stretching and deformation of the TNR. Postoperative MRI confirmed the complete removal of CPA tumors in 51 patients, while minor epidermoid residue in the contralateral cerebellopontine angle cistern was found in only one subject. There were no fatalities after surgical interventions, and the postsurgical cranial nerve neuropathies were transient and regressed within 2–3 months. In 15 cases, hypoesthesia developed or worsened in the trigeminal nerve innervation zone, then disappeared within several weeks, and was not accompanied by a recurrence of TN. Facial sensitivity improved in 6 cases, who had not previously undergone any surgical manipulations of the TNR and its peripheral branches. Complete regression of TN in the immediate postoperative period was observed in 51 patients. A percutaneous radiofrequency trigeminal rhizotomy was performed in 1 subject with an epidermoid tumor, to eliminate the intense pain paroxysms that persisted for a week. No recurrent growth of CPA tumors or relapses of TN were observed during the subsequent follow-up period of 2–10 years. Conclusion. TN can be caused by direct compression and deformation of the TNR and brainstem by CPA tumors and vascular structures. A detailed examination of the entire length of the TNR after tumor removal is necessary to evaluate the neurovascular relationships. In cases of vascular compression of the TNR, various methods of microvascular decompression can be used to treat TN.

The historical evolution of microvascular decompression for trigeminal neuralgia: from Dandy's discovery to Jannetta's legacy.

Although the symptoms of trigeminal neuralgia (TN) have been well described throughout the history of medicine, its etiology was initially not well understood by most surgeons. The standard procedure used to treat TN today, microvascular decompression (MVD), evolved due to the efforts of numerous neurosurgeons throughout the twentieth century. Walter Dandy was the first to utilize the cerebellar (suboccipital) approach to expose the trigeminal nerve for partial sectioning. He made unique observations about the compression of the trigeminal nerve by nearby structures, such as vasculature and tumors, in TN patients. In the 1920s, Dandy unintentionally performed the first MVD of the trigeminal nerve root. In the 1950s, Palle Taarnhøj treated a TN patient by performing the first intentional decompressive procedure on the trigeminal nerve root solely through the removal of a compressive tumor. By the 1960s, W. James Gardner was demonstrating that the removal of offending lesion(s) or decompression of nearby vasculature alleviated pressure on the trigeminal nerve and the pain associated with TN. By the 1990s, Peter Jannetta proved Dandy's original hypothesis; he visualized the compression of the trigeminal nerve at the root entry zone in TN patients using an intraoperative microscope. In this paper, we recount the historical evolution of MVD for the treatment of TN.

Microstructural changes in the trigeminal nerve of patients with episodic migraine assessed using magnetic resonance imaging

BackgroundThere is histological evidence of microstructural changes in the zygomaticotemporal branch of the trigeminal nerve in migraineurs. This raises the possibility that altered trigeminal nerve properties contribute to migraine pathophysiology. Whilst it is not possible to explore the anatomy of small trigeminal nerve branches it is possible to explore the anatomy of the trigeminal root entry zone using magnetic resonance imaging in humans. The aim of this investigation is to assess the microstructure of the trigeminal nerve in vivo to determine if nerve alterations occur in individuals with episodic migraine.MethodsIn 39 migraineurs and 39 matched controls, T1-weighted anatomical images were used to calculate the volume (mm3) and maximal cross-sectional area of the trigeminal nerve root entry zone; diffusion tensor images were used to calculate fractional anisotropy, mean diffusion, axial diffusion and radial diffusion.ResultsThere were significant differences between the left and right nerve of controls and migraineurs with respect to volume and not cross-sectional area. Migraineurs displayed reduced axial diffusion in the right nerve compared to the left nerve, and reduced fractional anisotropy in the left nerve compared to left controls. Furthermore, although there were no differences in mean diffusion or radial diffusion, regional analysis of the nerve revealed significantly greater radial diffusion in the middle and rostral portion of the left trigeminal nerve in migraineurs compared with controls.ConclusionsMigraine pathophysiology is associated with microstructural abnormalities within the trigeminal nerve that are consistent with histological evidence of altered myelin and/or organization. These peripheral nerve changes may provide further insight into migraine pathophysiology and enable a greater understanding for targeted treatments of pain alleviation.