Prediction of trigeminal nerve position based on the main feeding artery in petroclival meningioma.

The trigeminal nerve is often displaced by petroclival meningioma (PCM) compression, making it difficult to locate during PCM surgery. This study investigated whether the deviated position of the trigeminal nerve could be easily predicted using the main tumor feeding artery. We retrospectively examined 32 patients who underwent surgery for primary PCM. The deviation of the trigeminal nerve was classified as either Type 1 (displacement toward the back of the cerebellar tentorium), Type 2 (toward the back of the superior petrosal sinus), Type 3 (toward the back of the petrous apex dura), Type 4 (toward the inferior aspect of the tumor), or Type 5 (toward the surface of the brain stem). The main feeding artery was determined by preoperative angiography. The trigeminal nerve was classified as Type 2 in 60% of cases where the proximal tentorial artery (TA) was the main feeding vessel. The nerve was Type 5 where the distal portion of the TA was the main feeding vessel (60% of the cases). The nerves were Type 3 and Type 4 where the proximal inferior lateral trunk (ILT) (60%) and distal ILT (75%), respectively, were the main feeding vessels. In 66.7% of the cases where the dorsal meningeal artery was the main feeding vessel, the nerve was Type 3. Type 1 classification applied in all cases where the ascending pharyngeal artery was the main feeding artery. The main feeding artery can be used to predict trigeminal nerve transposition during PCM surgery.

Safety profile of superior petrosal vein (the vein of Dandy) sacrifice in neurosurgical procedures: a systematic review.

OBJECTIVE Walter E. Dandy described for the first time the anatomical course of the superior petrosal vein (SPV) and its significance during surgery for trigeminal neuralgia. The patient's safety after sacrifice of this vein is a challenging question, with conflicting views in current literature. The aim of this systematic review was to analyze the current surgical considerations regarding Dandy's vein, as well as provide a concise review of the complications after its obliteration. METHODS A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A thorough literature search was conducted on PubMed, Web of Science, and the Cochrane database; articles were selected systematically based on the PRISMA protocol and reviewed completely, and then relevant data were summarized and discussed. RESULTS A total of 35 publications pertaining to the SPV were included and reviewed. Although certain studies report almost negligible complications of SPV sectioning, there are reports demonstrating the deleterious effects of SPV obliteration when achieving adequate exposure in surgical pathologies like trigeminal neuralgia, vestibular schwannoma, and petroclival meningioma. The incidence of complications after SPV sacrifice (32/50 cases in the authors' series) is 2/32 (6.2%), and that reported in various case series varies from 0.01% to 31%. It includes hemorrhagic and nonhemorrhagic venous infarction of the cerebellum, sigmoid thrombosis, cerebellar hemorrhage, midbrain and pontine infarct, intracerebral hematoma, cerebellar and brainstem edema, acute hydrocephalus, peduncular hallucinosis, hearing loss, facial nerve palsy, coma, and even death. In many studies, the difference in incidence of complications between the SPV-sacrificed group and the SPV-preserved group was significant. CONCLUSIONS The preservation of Dandy's vein is a neurosurgical dilemma. Literature review and experiences from large series suggest that obliterating the vein of Dandy while approaching the superior cerebellopontine angle corridor may be associated with negligible complications. However, the counterview cannot be neglected in light of some series showing an up to 30% complication rate from SPV sacrifice. This review provides the insight that although the incidence of complications due to SPV obliteration is low, they can happen, and the sequelae might be worse than the natural history of the existing pathology. Therefore, SPV preservation should be attempted to optimize patient outcome.

Microvascular Decompression for Trigeminal Neuralgia Due to Venous Compression Alone.

Microvascular decompression (MVD) has been confirmed as an effective treatment of trigeminal neuralgia (TN); however, most previous reports just focused on MVD for TN caused by arterial conflict, there is a paucity of information about its use in venous compression causing TN. In the present study, the authors summarize 5-year experience of MVD for primary TN due to venous compression alone. Thirty-four patients with primary TN caused solely by veins underwent MVD. The presenting symptoms, key operative notes, surgical outcomes together with complications were reviewed. Of all the 34 patients, 19 (55.9%) patients occurred as typical TN. The V2 division was the most commonly affected area. Most of the venous conflicts were grade III (20/34, 58.8%). Deep superior petrosal venous system was the most frequent offending vessel (21/34, 61.8%). The venous conflicts were located at the trigeminal root entry zone in 10 (29.4%) patients, the mid cisternal zone in 18 (52.9%) patients, and the porus of Meckel's cave in 11 (32.4%) patients. At the last follow-up, excellent outcome was obtained in 26 (76.5%) patients, 7 (20.6%) patients got good outcome, fair outcome was achieved in 7 (20.6%) patients, and 1 patient unimproved (2.9%). Cerebrospinal fluid leakage was the most common complication (5.9%). In conclusion, MVD is a safe and effective surgical option for TN due to venous compression alone. It is noteworthy to explore the entire nerve and to protect veins as much as possible.

Trigeminal Neuralgia Attributable to Intraneural Trigeminocerebellar Artery: Case Report and Review of the Literature.

BACKGROUND: The trigeminocerebellar artery (TCA) is a branch of the basilar artery supplying both the trigeminal nerve root and the cerebellar hemisphere. Despite its proximity to the trigeminal nerve, only a few cases of trigeminal neuralgia (TN) caused by TCA compression of the trigeminal nerve have been reported. Moreover, TN caused by blood vessel penetration of the trigeminal nerve is very rare. CASE DESCRIPTION: We present a case of an 82-year-old female patient with typical episodes of TN. The radiologic studies showed that the offending artery was a unique branch of the basilar artery originating at a higher level than that of the usual anterior inferior cerebellar artery. During microvascular decompression surgery we were able to identify the offending vessel supplying the trigeminal nerve root and traveling between the sensory and motor root of the trigeminal nerve as an intraneural TCA. To shift the TCA away from the root entry zone, we dissected the epineurium of trigeminal nerve parallel to its axis and anchored the proximal portion of the TCA to the petrous dura. The patient's pain was completely gone immediately after the operation, with no neurologic deficits reported. CONCLUSIONS: The TCA is a potential offending vessel in TN because of trigeminal nerve compression, and the longitudinal dissection of the trigeminal nerve to make space between the vessel and the nerve roots may be an effective procedure to relieve TN caused by pressing intraneural vessels.

Trigeminal neuralgia caused by a trigeminocerebellar artery.

This 31-year-old woman presented with typical right trigeminal neuralgia caused by a trigeminocerebellar artery, manifesting as pain uncontrollable with medical treatment. Preoperative neuroimaging studies demonstrated that the offending artery had almost encircled the right trigeminal nerve. This finding was confirmed intraoperatively, and decompression was completed. The neuralgia resolved after the surgery; the patient had slight transient hypesthesia, which fully resolved within the 1st month after surgery. The neuroimaging and intraoperative findings showed that the offending artery directly branched from the upper part of the basilar artery and, after encircling and supplying tiny branches to the nerve root, maintained its diameter and coursed toward the rostral direction of the cerebellum, which indicated that the artery supplied both the trigeminal nerve and the cerebellum. The offending artery was identified as the trigeminocerebellar artery. This case of trigeminal neuralgia caused by a trigeminocerebellar artery indicates that this variant is important for a better understanding of the vasculature of the trigeminal nerve root.

Can the neurovascular compression volume of the trigeminal nerve on magnetic resonance cisternography predict the success of local anesthetic block after initial treatment by the carbamazepine?

OBJECTIVES: Whether NVC volume on magnetic resonance (MR) cisternography might be related to the success of local anesthetic block by tetracaine (TNB) as an additional treatment after carbamazepine (CBZ) treatments in patients with trigeminal neuralgia (TN) was evaluated. STUDY DESIGN: Detectable NVC volumes were measured from MR cisternography in 65 patients with TN treated by TNB after CBZ treatments. The correlation between the success of TNB and the NVC volume or the improvement in pain by CBZ was evaluated retrospectively. RESULTS: A significant difference was found between the improvement in pain by CBZ and the success of TNB, but not between NVC volume on MR cisternography and the success of TNB. CONCLUSIONS: The present results suggest that the success of CBZ as initial treatment, but not NVC volume on MR cisternography, may be a significant predictor of the success of TNB as additional therapy in patients with TN.

Nitric oxide synthase, calcitonin gene-related peptide and NK-1 receptor mechanisms are involved in GTN-induced neuronal activation.

BACKGROUND AND AIM: Infusion of glyceryltrinitrate (GTN), a nitric oxide (NO) donor, in awake, freely moving rats closely mimics a universally accepted human model of migraine and responds to sumatriptan treatment. Here we analyse the effect of nitric oxide synthase (NOS) and calcitonin gene-related peptide (CGRP) systems on the GTN-induced neuronal activation in this model. MATERIALS AND METHODS: The femoral vein was catheterised in rats and GTN was infused (4 µg/kg/min, for 20 minutes, intravenously). Immunohistochemistry was performed to analyse Fos, nNOS and CGRP and Western blot for measuring nNOS protein expression. The effect of olcegepant, L-nitro-arginine methyl ester (L-NAME) and neurokinin (NK)-1 receptor antagonist L-733060 were analysed on Fos activation. RESULTS: GTN-treated rats showed a significant increase of nNOS and CGRP in dura mater and CGRP in the trigeminal nucleus caudalis (TNC). Upregulation of Fos was observed in TNC four hours after the infusion. This activation was inhibited by pre-treatment with olcegepant. Pre-treatment with L-NAME and L-733060 also significantly inhibited GTN induced Fos expression. CONCLUSION: The present study indicates that blockers of CGRP, NOS and NK-1 receptors all inhibit GTN induced Fos activation. These findings also predict that pre-treatment with olcegepant may be a better option than post-treatment to study its inhibitory effect in GTN migraine models.

[Intraoperative decisions and surgical efficacies of trigeminal neuralgia responsible vessels].

OBJECTIVE: To explore the types of primary trigeminal neuralgia (TN) responsible vessels and curative efficacies of microscopic vascular decompression (MVD). METHODS: A total of 162 primary TN patients underwent MVD from August 2004 to the present at our hospital.Their clinical data were collected and analyzed. There were 69 males and 93 females with an age range of 22-88 years. RESULTS: The most common responsible vessels were superior cerebellar artery (n = 65, 40.12%), anteroinferior cerebellar artery (n = 45, 27.78%), multiple vessels (n = 26, 16.05%), posteroinferior cerebellar artery (n = 16, 9.88%), veins (n = 6, 3.70%) and vertebral artery (n = 4, 2.47%). And the pressure points were at the root of trigeminal nerve (n = 139, 85.80%), distal part (n = 16, 9.88%) and root and distal part (n = 7, 4.32%). Postoperatively pain disappeared in all patients (including one case on second surgery). Postoperative follow-ups were conducted for 132 cases.Two cases recurred over 8 years and the recurrence rate was 1.52%. CONCLUSION: MVD is preferred method for primary TN non-responsive to pharmacotherapy. Identification and treatment of responsible vessels remain a key. Venous and distal pressure points should be taken care.

Hemimasticatory spasm treated with microvascular decompression of the trigeminal nerve.

Hemimasticatory spasm is a very rare disorder of the trigeminal nerve characterized by paroxysmal involuntary contraction of the jaw-closing muscles. The mechanisms leading to hemimasticatory spasm are still unclear. Recently, injection of botulinum toxin has become the treatment of choice due to its excellent results. We report a case of a successful treatment of hemimasticatory spasm via microvascular decompression of the motor branch of the trigeminal nerve.

Preoperative demonstration of neurovascular relationship in trigeminal neuralgia by using 3D FIESTA sequence.

PURPOSE: The purpose of the study was to evaluate the value of high-resolution three-dimensional fast imaging employing steady-state acquisition (3D FIESTA) imaging in the visualization of neurovascular relationship in patients with trigeminal neuralgia (TN). METHODS: Thirty-seven patients with unilateral typical TN underwent 3D FIESTA imaging. Neurovascular relationship at the trigeminal root entry zone was reviewed by an experienced neuroradiologist, who was blinded to the clinical details. The imaging results were compared with the operative findings in all patients. RESULTS: In 37 patients with TN, 3D FIESTA imaging identified surgically verified neurovascular contact in 35 of 36 symptomatic nerves. Based on surgical findings, the sensitivity and specificity of magnetic resonance (MR) imaging were 97.2% and 100%, respectively. Agreement between the position (medial, lateral, superior and inferior) of the compressing vessel relative to the trigeminal nerve identified by MR imaging and surgery was excellent (K=0.81; 95% confidence interval, 0.56-1.00). A statistically significant difference was found between the site of neurovascular contact and the clinical symptom related to the trigeminal branch (Fisher's Exact Test, P<.001). CONCLUSIONS: Use of 3D FIESTA sequence enables accurate visualization of neurovascular contact in patients with TN. Anatomic relationships defined by this method can be useful in surgical planning and predicting surgical findings.

Trigeminal neuralgia and persistent trigeminal artery.

We report a case of trigeminal neuralgia caused by persistent trigeminal artery (PTA) associated with asymptomatic left temporal cavernoma. Our patient presented unstable blood hypertension and the pain of typical trigeminal neuralgia over the second and third divisions of the nerve in the right side of the face. The attacks were often precipitated during physical exertion. MRI and Angio-MRI revealed the persistent carotid basilar anastomosis and occasionally left parietal cavernoma. After drug treatment of blood hypertension, spontaneous recovery of neuralgia was observed and we planned surgical treatment of left temporal cavernoma.

Structural abnormalities of the trigeminal root revealed by diffusion tensor imaging in patients with trigeminal neuralgia caused by neurovascular compression: a prospective, double-blind, controlled study.

Because diffusion tensor imaging (DTI) is able to assess tissue integrity, we used diffusion to detect abnormalities in trigeminal nerves (TGN) in patients with trigeminal neuralgia (TN) caused by neurovascular compression (NVC). We also studied anatomical TGN parameters (cross-sectional area [CSA] and volume [V]). Using DTI sequencing in a 3-T magnetic resonance imaging (MRI) scanner, we measured the fraction of anisotropy (FA) and the apparent diffusion coefficient (ADC) of TGN in 10 patients selected as candidates to have microvascular decompression (MVD) for TN, and 6 normal control subjects. We compared data between the affected nerves of TN (ipsilateral TN), unaffected nerves of TN (contralateral TN), and both nerves in normal subjects (controls), and correlated these data with CSA and V. The FA of the ipsilateral TN (0.37±0.08) was significantly lower (P<.05) compared with the contralateral TN (0.48±0.08) and control values (0.52±0.04). The ADC of ipsilateral TN (5.6±0.89 mm(2)/s) was significantly higher (P<.05) compared with the contralateral TN (4.26±0.59 mm(2)/s) and control values (3.84±0.43 mm(2)/s). Ipsilateral TN had less V and CSA compared with contralateral TN and control values (P<.05). The Spearman correlation coefficient showed a strong positive correlation between loss of FA and loss of V (r=0.7576) and loss of CSA (r=0.9273) of affected nerves. The Spearman correlation coefficient showed a strong negative correlation between increase in ADC and loss of V (r=-0.7173) and loss of CSA (r=-0.7416) in affected nerves. DTI revealed alteration in the FA and ADC values of the affected TGN. These alterations were correlated with atrophic changes in patients with TN caused by NVC.

Endoscopic vascular decompression of the trigeminal nerve.

BACKGROUND: Microvascular decompression is an effective method of treatment in trigeminal neuralgia. It may fail if a compressing vessel is overlooked during surgery. The endoscope has an edge over the microscope in visualizing such conflicts. MATERIALS AND METHODS: This is a prospective study of 51 patients. Preoperative computed tomography and magnetic resonance imaging scans were performed in all the cases. A 4 − 5 cm retroauricular skin incision was made and an about 3 cm craniectomy was performed. A 0° 4 mm telescope supported by the holder was used after the dural opening. A 2 by 6 cm sheet prepared from hand gloves was used to protect the brain. A Karl Storz 30° telescope was used for the visualization of the trigeminal nerve from the pons to Meckel's cave and dissection of the anterior conflict. Small pieces of dura patch were interposed between the nerve and the vessel. The microscope was not used at any stage. Post-operative infection, cerebrospinal fluid leak, cranial nerve deficit, failure of procedure in terms of pain relieves and recurrences of pain were recorded. The follow-up period ranged from 24 to 55 months with an average of 36 months. RESULTS: There was no mortality or any major permanent complications. The duration of stay ranged from 3 to 10 days with an average of 3.6 days. The pain was relieved in 48 patients. CONCLUSION: Endoscopic vascular decompression is an effective and safe alternative to endoscopic assisted microvascular decompression in trigeminal neuralgia.

Anterior communicating artery aneurysm associated with an infraoptic course of anterior cerebral artery and rare variant of the persistent trigeminal artery: a case report and literature review.

Infraoptic course of the precommunicating segment of the anterior cerebral artery (A1) is a rare anomaly. Furthermore, the presence of this anomaly associated with persistent trigeminal artery variant has been reported in the literature only once. We present a patient who had infraoptic course of A1 associated with an ipsilateral persistent trigeminal artery variant arising from the right internal carotid artery with no apparent connection to the basilar artery. The persistent trigeminal artery variant supplied to the right posteroinferior cerebellar artery territory. The patient also had hypoplastic left vertebral artery, superior cerebellar arteries originating from posterior cerebellar arteries bilaterally, and a bilobed aneurysm of the anterior communicating artery. The aneurysm was clipped and the infraoptic course was verified during the surgery. The post-operative course was uneventful and a follow-up arteriogram on the 7th postoperative day revealed successful obliteration of the aneurysm. We reviewed the literature with respect to presentation, associated vascular anomalies, imaging, associated cerebral aneurysms and other cerebral abnormalities, and treatment of the associated aneurysms. A discussion of the embryogenesis of this rare anomaly is also provided.

Giant, thrombosed, sellar-suprasellar internal carotid artery aneurysm with persistent, primitive trigeminal artery causing hypopituitarism.

A rare case of a giant, thrombosed, sellar-suprasellar paraclinoid internal carotid artery (ICA) aneurysm with persistent primitive trigeminal artery (PPTA) causing hypopituitarism that manifested as hypogonadism, hypothyroidism, and hypocortisolism is reported. There were no visual/neurological deficits, diabetes insipidus, or episodes of subarachnoid hemorrhage. The alteration in the flow dynamics of the circle of Willis due to the presence of PPTA may have been responsible for both the genesis of the giant aneurysm as well as for the induction of thrombogenesis within its lumen. As the digital subtraction angiogram showed complete thrombosis within the aneurysm and hormonal replacement therapy was effective in ensuring complete normalization of symptoms, the patient was unwilling to undergo surgical clipping of the aneurysm and removal of the suprasellar clot in an attempt to restore pituitary functions. Hypopituitarism recurred when the patient stopped her hormonal supplementation therapy after 7 years, and she again became symptom-free on restarting the therapy. To the best of the authors' knowledge, this represents the first reported case in the literature of hypopituitarism consequent to a giant, thrombosed, sellar-suprasellar ICA aneurysm with an associated PPTA on the side of the aneurysm.

Vasculature and neurovascular relationships of the trigeminal nerve root.

BACKGROUND: Specific microanatomical characteristics of the trigeminal nerve root (TNR) blood supply and close neurovascular relationships with surrounding vessels as well as their possible clinical significance were the main reasons for this study. METHOD: The vasculature of 25 adult and four fetal TNRs were microdissected and examined under the stereoscopic microscope, after injecting their arteries with India ink. RESULTS: The trigeminal vessels, which varied between two and five in number, arose from two or three of the following arteries: the superolateral pontine (92%), anterior inferior cerebellar (AICA) (88%), inferolateral pontine (72%), and superior cerebellar (SCA) (12%). The trigeminal vascular twigs had a mean diameter of 0.215 mm. A single vessel may supply either the motor portion of the nerve root or the sensory portion or both. The trigeminal vasculature formed the proximal and distal rings. The proximal ring was located at the trigeminal root entry zone. Its central branches extended along the TNR to the principal sensory and motor trigeminal nuclei while its peripheral longitudinal twigs followed the TNR fascicles. The incomplete distal arterial ring embraced the middle portion of the TNR before the level of its entrance into the arachnoid sleeve. The most frequent contact of the TNR was noticed with the SCA (20%), the petrosal or Dandy's vein (24%), and the AICA (12%). CONCLUSIONS: The observed characteristics of the TNR vasculature could be the anatomical basis for decompressive neurovascular surgery.

Endovascular occlusion of a lacerated primitive trigeminal artery during surgical resection of clival chordoma. a case report.

We describe a case of a persistent primitive trigeminal artery (PPTA) coexistent with a clival chordoma. During surgery of the tumor, the partially incorporated PPTA was inadvertently traumatized and ruptured. The operation was discontinued and the PPTA was endovascularly occluded permitting further safe resection of the tumor.

Preoperative demonstration of the neurovascular compression characteristics with special emphasis on the degree of compression, using high-resolution magnetic resonance imaging: a prospective study, with comparison to surgical findings, in 100 consecutive patients who underwent microvascular decompression for trigeminal neuralgia.

PURPOSE: Surgical outcome after microvascular decompression (MVD) for primary trigeminal neuralgia (TN) has been demonstrated as being related to the characteristics of the neurovascular compression (NVC), especially to the degree of compression exerted on the root. Therefore, preoperative determination of the NVC features could be of great value to the neurosurgeon, for evaluation of conflicting nature, exact localization, direction and degree of compression. This study deals with the predictive value of MRI in detecting and assessing features of vascular compression in 100 consecutive patients who underwent MVD for TN. METHODS: The study included 100 consecutive patients with primary TN who were submitted to a preoperative 3D MRI 1.5 T with T2 high-resolution, TOF-MRA, and T1-Gadolinium. Image analysis was performed by an independent observer blinded to the operative findings and compared with surgical data. FINDINGS: In 88 cases, image analysis showed NVC features that coincided with surgical findings. There were no false-positive results. Among 12 patients that did not show NVC at image analysis, nine did not have NVC at intraoperative observation, resulting in three false-negative cases. MRI sensitivity was 96.7% (88/91) and specificity 100% (9/9). Image analysis correctly identified compressible vessel in 80 of the 91 cases and degree of compression in 77 of the 91 cases. Kappa-coefficient predicting degree of root compression was 0.746, 0.767, and 0.86, respectively, for Grades I (simple contact), II (distortion), and III (marked indentation; p < 0.01). CONCLUSION: 3D T2 high-resolution in combination with 3D TOF-MRA and 3D T1-Gadolinium proved to be reliable in detecting NVC and in predicting the degree of the root compression.

Variant intraneural vein-trigeminal nerve relationships: an observation during microvascular decompression surgery for trigeminal neuralgia.

OBJECTIVE: Trigeminal neuralgia is often caused by compression, demyelination, and injury of the trigeminal nerve root entry zone by an adjacent artery and/or vein. Previously described variations of the nerve-vessel relationship note external nerve compression. We offer a detailed classification of intraneural vessels that travel through the trigeminal nerve and safe, effective surgical management. CLINICAL PRESENTATION: We report 3 microvascular decompression operations for medically refractory trigeminal neuralgia during which the surgeon encountered a vein crossing through the trigeminal nerve. Two types of intraneural veins are described: type 1, in which the vein travels between the motor and sensory branches of the trigeminal nerve (1 patient), and type 2, in which the vein bisects the sensory branch (portio major) (2 patients). INTERVENTION: We recommend sacrificing the intraneural vein between the motor and sensory branches if the vein is small (most likely type 1). If the intraneural vein is large and bisects the sensory branch (most likely type 2), vein mobilization can be achieved, but often requires extensive dissection through the nerve. Because this maneuver may lead to trigeminal nerve injury and result in uncomfortable neuropathy and numbness (including corneal hypoesthesia), we recommend against mobilization of the vein through the nerve, suggesting instead, consideration of a selective trigeminal nerve rhizotomy. CONCLUSION: Because aggressive dissection of intraneural vessels can lead to higher than normal complication rates, preoperative knowledge of vein-trigeminal nerve variants is crucial for intraoperative success.