Neurovascular Contact Research Articles

Impact of microvascular decompression on wall shear stress in responsible arteries in trigeminal neuralgia and hemifacial spasm.

Microvascular decompression (MVD) has proven efficacy in trigeminal neuralgia (TN) and hemifacial spasm (HFS). This study utilized computational fluid dynamics (CFD) to investigate the impact of MVD on wall shear stress (WSS) of responsible arteries (RAs) at the neurovascular contact (NVC). A total of 21 cases (10 TN, 11 HFS) were analyzed, involving RAs at NVC validated through intraoperative photographs. Hemodynamic parameters (WSS, vessel diameter, flow rate, pressure drop) was calculated using CFD for the RAs based on 3D silent-magnetic resonance angiograms. The NVC was segmented into NVC-proximal, NVC-site, and NVC-distal portions using simulated 3D CFD images that correlated with surgical observations. WSS ratios of NVC-site to NVC-proximal (NVC-site/proximal) was calculated both before and after MVD. Prior to MVD, WSS in the RA at the NVC displayed a peaked curve with a maximum at NVC-site; however, post MVD, it presented a smooth curve without peaks. The WSS ratio exhibited a significant decrease after MVD. The impact of MVD on WSS of RAs at NVC was evaluated in both TN and HFS cases. Analyzing the hemodynamics of RAs through CFD and identifying WSS peaks at NVC portions before MVD provided a more detailed and localized understanding of the morphologically depicted NVC.

Establishment of a Clinical Prediction Model Based on the Study of Risk Factors for Pain Recurrence after Percutaneous Radiofrequency Thermocoagulation in Patients with Primary Trigeminal Neuralgia

Objectives: This study aimed to investigate the follow-up outcomes and risk factors associated with pain recurrence after percutaneous radiofrequency thermocoagulation (PRT) among patients with primary trigeminal neuralgia (PTN) and to establish a clinical prediction model based on these risk factors. Methods: The data of PTN patients who underwent PRT were collected in our study. All subjects were randomly divided at a 7:3 ratio into a training group (T Group) and a test group (C Group) to select risk factors. According to the follow-up results, the patients were divided into a recurrence group (F Group) and a nonrecurrence group (NF Group). Predictive factors were selected through LASSO regression analysis based on T Group. The identified variables were subjected to multivariate logistic regression analysis to construct a nomogram. Receiver operating characteristic (ROC) curves and calibration curves were uesd to evaluate discrimination and calibration ability separately. Results: A total of 884 patients were initially included, 857 patients achieved satisfactory results, and the pain relief rate at discharge was 96.95%. A total of 529 subjects were included after screening, and the recurrence rate was 27.22% after 1 year. Six non-zero variables were selected through LASSO regression analysis: the disease course, atypical pain, previous surgery, facial numbness before PRT, neurovascular contact (NVC), and operation duration. Six variables were included in the multivariate logistic regression analysis, and the results showed that they were independent risk factors (P<0.05). The predictive model is represented by a nomogram. The area under the curves (AUC) of the ROC curves were 0.868 (0.826~0.909) and 0.874 (0.802~0.950) for T Group and C Group, respectively. The prediction curves for T Group (P=0.784) and C Group (P=0.293) fit the ideal prediction curve, and the Brier scores were 0.120 and 0.099 for T Group and C Group, which indicates that the probability predicted by the model is consistent with the actual occurrence. Conclusion: The Pain relief rate at discharge was 96.95% for PTN patients after PRT, and the recurrence rate was 27.22% after 1 year. The disease course, atypical pain, previous surgery, facial numbness before PRT, NVC, and operation duration are independent risk factors for the recurrence of pain. A nomogram model for pain recurrence was established, which has good predictive ability.

Assessment of prevalence of vascular contact of the facial nerve in asymptomatic patients using three-dimensional constructive interference in steady-state (3D CISS) MRI acquisition.

To evaluate the prevalence of vascular contact of the facial nerve in patients without hemifacial spasm or facial palsy using magnetic resonance imaging (MRI). Our radiology database was accessed to find a series of consecutive adult patients who underwent MRI of the brain during the study period, excluding those with a history of hemifacial spasm (HFS), facial palsy, traumatic brain injury, intracranial tumour, intracranial surgery, trigeminal neuro-vascular compression, brain radiation therapy, and studies with poor image quality. A total of 112 (224 sides) MRIs of the posterior fossa were independently reviewed by 2 radiologists for neurovascular contact involving the facial nerve. The presence of neuro-vascular contact, the number of points of contact, the location of contact along the intracranial course of the facial nerve, the culprit vessel, and the severity of compression were recorded in the CISS MRI sequence in the cohort of patients without HFS and facial palsy. The prevalence of neurovascular contact involving the facial nerve can be as high as 51% in patients asymptomatic for HFS and facial palsy. It is frequently caused by the anterior inferior cerebellar artery and commonly involves the cisternal portion with mild to moderate severity. In asymptomatic patients, the pulsatile neurovascular contact of the intracranial segment of the facial nerve typically occurs at one point, involving the distal portion with milder severity in contrast to patients with HFS. These results in the asymptomatic cohort should be considered when evaluating the candidacy of HFS patients for microvascular decompression.

Independent association of the Meckel’s cave with trigeminal neuralgia and development of a screening tool

PurposeTo 1) investigate the association of the properties of the Meckel’s cave (MC) with TN occurrence (i.e., affected vs. unaffected nerves) and whether such association was independent of neurovascular contact (NVC); and 2) develop an objective screening tool for TN. Materials and methodsTwo hundred and nineteen trigeminal nerves were included. (The severity of) NVC was identified for individual nerve, and a set of 107 radiomic features were extracted to characterize various properties of each MC. Both procedures were primarily based on magnetic resonance imaging sequences. A radiomic score (Rad-score) was constructed for each MC to integrate the features associated with TN occurrence. Independent t-test and logistic regression were conducted to assess the association and develop the screening tool mentioned above. ResultsTwelve features were selected to build the Rad-score, with the Inverse Difference Moment Normalized (IDMN) having the greatest weight. The Rad-score was significantly (p ≤ 0.05) higher in the affected compared to the unaffected nerves, irrespective of NVC. The Rad-score and NVC were incorporated in the regression model/screening tool, which demonstrated an acceptable discriminating ability (C-statistic = 0.84). ConclusionThis study has identified a potential association of the properties/features of the MC with TN occurrence, probably involving the demyelination and axonal injury of the trigeminal ganglion within the MC as suggested by the IDMN. Such association may be independent of NVC. This finding may provide new insight into the etiology and/or pathophysiology of TN. The screening tool, which demonstrated an acceptable discriminating ability, may contribute to an improvement in its diagnosis.

Use of indocyanine green angiography during endoscopic microvascular decompression for trigeminal neuralgia

BackgroundThe aim of this study was to assess the efficacy of indocyanine green (ICG) angiography during full endoscopic microvascular decompression for trigeminal neuralgia. MethodsWe extracted retrospective data of patients who received ICG videoangiography during full endoscopic microvascular decompression for trigeminal neuralgia. Preoperative neurovascular contact was evaluated by three-dimensional (3D) fusion images using image analysis software Ziostation2 (ZIOSOFT, Tokyo, Japan) and Intraoperative ICG angiography was used in pre and post ICG injection to identify and assess blood flow in the offending vessel for adequate transposition planification and assess for immediate post transposition blood flow or vasospasm respectively. Patients were assessed the next morning for early signs of brainstem infarction and at one month follow up. ResultsThere were 44 patients. All patients had ICG videoangiography done during the procedure. The mean age was 65.5 and male female ratio 3.4:1. Some anatomical variants were identified during this procedure. Five patients (11.3%) had a trigeminocerebellar artery, three patients (6.8%) had a developed superior petrosal vein and one patient (2.2%) had dural adhesions with encasement of anterior inferior cerebellar artery. Among the 44 patients enrolled, 34 had transposition done and 10 had combined transposition either with neurolysis or Teflon interposition. The main offending vessel was Superior cerebellar artery (SCA) in 23 patients (67.6%). In 5 (14.7%) of 34 patients who underwent Transposition, vasospasm was seen and no complications were observed in all patients but 93.1% had good pain control in postoperative. ConclusionICG angiography in endoscopic microvascular decompression is safe and effective in depicting the offending vessel, its branches and some perforators and contributes significantly to the determination of treatment strategy.

A Systematic Review of the Role of Magnetic Resonance Imaging in the Diagnosis and Detection of Neurovascular Conflict in Patients With Trigeminal Neuralgia.

Trigeminal neuralgia (TN) is a debilitating disorder causing severe, episodic, unilateral stabbing facial pain disturbing enough to disrupt the activities of daily life. Classic TN is caused due to compression injury of the trigeminal nerve at the cistern segment caused by either an artery or a vein, referred to as neurovascular contact or conflict (NVC). Magnetic resonance imaging (MRI) has been the standard tool for the diagnosis of NVC. This study aimed to determine the incidence of NVC in TN, as identified by MRI, assess the various MRI grading patterns among patients with TN, and identify the vessels primarily involved in NVC. A systematic search of studies that used MRI for the diagnosis of TN in reference to NVC was conducted on DOAJ and PubMed/PubMed Central. Data were extracted and entered into a Microsoft Excel spreadsheet. The outcomes measured were the incidence of NVC as shown in MRI, vessels involved in NVC, and MRI grading patterns. We identified and selected 20 studies that fulfilled inclusion/exclusion criteria. In total, 1,436 patients were enrolled in all included studies. The type of MRI used was 1.5 T or 3 T MRI. The mean age of the patients varied from 49 to 63 years, with an equivalent male-to-female ratio. NVC was seen in 1,276 cases out of 1,436 cases (88.85%) of TN on the ipsilateral side, as shown by MRI. The vessels involved were arteries in 80-90% of the cases, followed by veins. Among the arteries, the superior cerebellar artery was the most common artery (80-90% of cases). The grades of NVC as assessed by MRI included grades I, II, and III with varied proportions in different studies. NVC is a common problem in TN, wherein there is compression at the nerve root entry zone, and it shows a strong predilection for the elderly population. MRI seems to be a novel imaging diagnostic investigation to identify NVC associated with TN. Moreover, NVC grading must be done with MRI so that it may help the surgeon in stratifying the patient's treatment.

Online dynamic nomogram for predicting pain recurrence after microvascular decompression in trigeminal neuralgia.

Trigeminal neuralgia (TN) is one of the most common causes of facial pain. Microvascular decompression (MVD) is the first-choice surgical treatment. The present study aimed to develop a novel practical assessment system based on preoperative clinical and imaging factors for clinicians to predict the likelihood of pain recurrence following MVD in TN. A total of 56 patients with primary unilateral TN who underwent MVD were retrospectively analyzed. Patients were followed up to observe pain recurrence 1 year after MVD. An online dynamic nomogram was constructed for predicting the probability of pain recurrence after MVD in patients with TN based on multivariate logistic model. The concordance index (C-index) and receiver operating characteristic (ROC) were used to measure model discrimination. Bootstrap resampling was used for internal validation of the model and calibration curve was constructed. Decision curve analysis (DCA) was used to assess clinical applicability. Factors such as numeric rating scale (to score pain degree of patients with TN), response to neuroanalgesic drugs and neurovascular contact on magnetic resonance imaging were independent risk factors affecting the pain recurrence rate (all P<0.05). C-index was 0.973 (95%CI, 0.938-1.000) and the area under the ROC was 0.973 (95%CI, 0.938-1.000). Calibration curve with a 1,000 bootstrap resampling showed a good fit between dynamic nomogram prediction and actual observations. The DCA showed that at a threshold probability between 0 and 100%, this model can achieve a greater net benefit than if all patients had surgery or none had surgery. In conclusion, this online dynamic nomogram reliably predicted risk of pain recurrence in patients with TN following MVD.

A Practical Review of Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a highly disabling disorder characterized by very severe, brief, electric shocks, like recurrent episodes of facial pain. New diagnostic criteria classifying TN on the basis of the presence of trigeminal neurovascular conflict or an underlying neurological disorder can help better characterize patients and determine treatments. Magnetic resonance imaging using specific sequences should be a part of the diagnostic workup to detect a possible neurovascular contact and exclude secondary causes. Carbamazepine and oxcarbazepine are drugs of first choice for long-term treatment, whereas microvascular decompression is the first-line surgical management of medically refractory patients. This review aimed to review the classification, clinical features, pathophysiology, diagnostic approaches, and management of TN.

Trigeminal neuralgia caused by a persistent primitive trigeminal artery: preoperative three-dimensional multifusion imaging and computational fluid dynamics analysis. Illustrative case.

Trigeminal neuralgia (TN) is caused by trigeminal nerve compression by colliding vessels. Preoperative three-dimensional (3D) multifusion images are useful for surgical simulations. Moreover, computational fluid dynamics (CFD) analysis of colliding vessels may be useful for hemodynamic evaluation at the site of neurovascular contact (NVC). A 71-year-old woman had TN due to compression of the trigeminal nerve by the superior cerebellar artery (SCA) fused with the persistent primitive trigeminal artery (PTA). Preoperative 3D multifusion simulation images of silent magnetic resonance (MR) angiography and MR cisternography depicted the NVC, including the trigeminal nerve, SCA, and PTA. CFD analysis revealed the hemodynamic condition of the NVC, including the SCA and PTA. The wall shear stress magnitude (WSSm) at the NVC showed a local elevation due to flow confluence from the SCA and PTA. High WSSm was observed in the NVC. Preoperative simulation images of MR angiography and MR cisternography may depict the NVC. CFD analysis can provide the hemodynamic condition at the NVC.

Predictive value of preoperative magnetic resonance imaging structural and diffusion indices for the results of trigeminal neuralgia microvascular decompression surgery

PurposeTo explore the predictive value of preoperative magnetic resonance imaging structural and diffusion indices of the spinal trigeminal tract (SpTV) on the results of microvascular decompression (MVD) in patients with trigeminal neuralgia (TN).MethodsThis retrospective study included patients diagnosed with TN and treated with MVD in the Jining First People’s Hospital between January 2020 and January 2021. The patients were divided into good and poor results groups according to postoperative pain relief. Logistic regression analysis was performed to explore independent risk factors for poor results of MVD, and their predictive value was examined using receiver operating characteristic (ROC) curves.ResultsA total of 97 TN cases were included, 24 cases with a poor result and 73 with a good result. They were comparable in demographic characteristics. Fractional anisotropy (FA) was lower (P < 0.001), and radial diffusivity (RD) was higher (P < 0.001) in the poor result group compared to the good result group. Patients in the good result group showed a higher proportion of grade 3 neurovascular contact (NVC) (39.7% vs. 16.7%, P = 0.001) and a lower RD (P < 0.001). The multivariate analysis showed that the RD of SpTV (OR = 0.000016, 95% CI: 0.000–0.004, P < 0.001) and NVC (OR = 8.07, 95% CI: 1.67–38.93, P = 0.009) were independently associated with poor results. The area under the curve (AUC) of RD and NVC were 0.848 and 0.710, and their combination achieved an AUC of 0.880.ConclusionNVC and RD of SpTV are independent risk factors for poor results after MVD surgery, and combining the NVC and RD might achieve relatively high predictive value for poor results.

Efficacy of surgical treatment in patients with trigeminal neuralgia secondary to multiple sclerosis: A prospective study of 18 cases with evaluation of outcome and complications by independent evaluators.

Medical treatments for trigeminal neuralgia secondary to multiple sclerosis have low efficacy and tolerability and scientific evidence regarding efficacy of neurosurgery is scarce. We aimed to assess neurosurgical outcome and complications in trigeminal neuralgia secondary to multiple sclerosis. Patients with trigeminal neuralgia secondary to multiple sclerosis who underwent microvascular decompression, glycerol rhizolysis or balloon compression were prospectively and consecutively included from 2012 to 2019. Preoperatively, we systematically obtained clinical characteristics and performed a 3.0 Tesla MRI. Follow-up at three, six and 12 months was performed by independent assessors. We included 18 patients. Of the seven patients treated with microvascular decompression, two patients (29%) had an excellent outcome (both had neurovascular contact with morphological changes), three patients (43%) had a good outcome, one patient (14%) had treatment failure and one patient (14%) had a fatal outcome. Three patients (43%) had major complications. Of 11 patients treated with percutaneous procedures, seven patients (64%) had an excellent or good outcome with major complications in three patients (27%). Percutaneous procedures provided acceptable outcome and complication rates and should be offered to the majority of patients with trigeminal neuralgia secondary to multiple sclerosis who need surgery. Microvascular decompression is less effective and has a higher complication rate in trigeminal neuralgia secondary to multiple sclerosis compared to microvascular decompression in classical and idiopathic trigeminal neuralgia. Microvascular decompression should only be considered in patients with trigeminal neuralgia secondary to multiple sclerosis when they have neurovascular contact with morphological changes.

CLINICAL PRACTICE GUIDELINES IN TRIGEMINAL NEURALGIA

A neurological disorder called trigeminal neuralgia is characterized by intense, sharp, and stabbing pain. Causes pertaining to Pathophysiology, clinical features, and management are still unsettled. An appropriate diagnosis is important for proper management. To identify potential neurovascular contact, MRI should be used in the diagnosis. Correct surgical care is aided by the demonstration of neurovascular etiology. Carbamazapine and oxcarbazepine are the first line drugs to treat trigeminal neuralgia. Early surgical care may be necessary in some trigeminal neuralgia patients who are resistant to pharmacological therapy. The longest-lasting methods of pain treatment or pain independence include microvascular decompression, percutaneous methods, and gamma knife. The development of more efficient and effective treatment options is highly warranted

Neurovascular Compression Syndromes: A Pictorial Essay

Neurovascular compression syndromes are typically brought on by arteries that come into contact with a cranial nerve’s (CN) cisternal section. Neurovascular contact does not always present with clinical symptoms. The most susceptible area for symptomatic neurovascular compression syndromes is the transitional zone between the peripheral and central myelin. Individual CN functional abnormalities are the clinical hallmark of neurovascular compression disorders. We present a series of four cases of patients presenting to a tertiary care center in Central India with symptoms and signs of neurovascular compression syndrome.

Internal neurolysis versus intraoperative glycerin rhizotomy for trigeminal neuralgia.

Internal neurolysis (IN) and intraoperative glycerin rhizotomy (ioGR) are emerging surgical options for patients with trigeminal neuralgia without neurovascular contact. The objective of this study was to compare the neurological outcomes of patients who underwent IN with those of patients who underwent ioGR. The authors retrospectively reviewed all patients who underwent IN or ioGR for trigeminal neuralgia at our institution. Patient demographic characteristics and immediate postoperative outcomes, as well as long-term neurological outcomes, were compared. Of 1044 patients who underwent open surgical treatment for trigeminal neuralgia, 56 patients underwent IN and 91 underwent ioGR. Of these 147 patients, 37 had no evidence of intraoperative neurovascular conflict. All patients who underwent IN and 96.7% of patients who underwent ioGR had immediate postoperative pain relief. At last follow-up, patients who underwent IN had lower Barrow Neurological Institute (BNI) pain intensity scores (p = 0.05), better BNI facial numbness scores (p < 0.01), and a greater degree of pain improvement (p = 0.05) compared with those who underwent ioGR. Patients who underwent IN also had significantly lower rates of symptomatic pain recurrence (p < 0.01) at last follow-up over an average of 9.5 months. IN appears to provide patients with a greater degree of pain relief, lower rates of facial numbness, and lower rates of pain recurrence compared with ioGR. Future prospective studies will better characterize long-term pain recurrence and outcomes.

Various Presentations Associated with Enhancement of the V2 Branch of the Trigeminal Nerve

The two patients discussed in this case report presented with radiologic enhancement of the V2 segment of the trigeminal nerve. The first patient discussed in this case report is a 78-year-old female with a history of squamous cell carcinoma of the face who presented with paresthesias involving the left V2 segment of the trigeminal nerve. A maxillofacial MRI was performed that showed subtle, thin enhancement along the outer margin of the left maxilla, and enhancement along the anterior course of V2. These findings suggested the possibility of V2 perineural spread of a tumor secondary to squamous eccrine duct carcinoma. The second case discusses a 71-year-old female who presented with symptoms of trigeminal neuralgia. An MRI was performed and showed thickening and enhancement of the right infraorbital nerve within the maxillary sinus with no significant neurovascular contact at the root entry zone. Further assessment by neurosurgery suggested this patient likely had isolated neuritis of the right infraorbital nerve, causing severe classic neuralgic symptoms. The third case presents a 28 year old male with MRI findings showing bilateral V2 enhancement within the anterior maxillary infraorbital foramina bilaterally. These three cases emphasize the importance of understanding the anatomy of the trigeminal nerve and maintaining a comprehensive knowledge of the common pathologies that affect cranial nerves. This awareness is critical in appropriately recognizing and diagnosing V2 pathologies and identifying their unique characteristics on various imaging modalities.

Microvascular decompression in trigeminal neuralgia - a prospective study of 115 patients

BackgroundTrigeminal neuralgia is a severe facial pain disorder. Microvascular decompression is first choice surgical treatment of patients with classical TN. There exist few prospective studies with an independent evaluation of efficacy and complications after MVD.ObjectivesWe aimed to assess outcome and complications after microvascular decompression from our center.MethodsWe prospectively recorded clinical characteristics, outcome, and complications from consecutive patients with either classical or idiopathic (only patients with a neurovascular contact) trigeminal neuralgia undergoing microvascular decompression. Neurovascular contact was evaluated by 3.0 Tesla MRI. Patients were assessed before and 3, 6, 12, and 24 months after surgery by independent assessors.ResultsOf 115 included patients, 86% had a clinically significant outcome (i.e., BNI I – BNI IIIb). There was a significant association between an excellent surgical outcome and the male sex (OR 4.9 (CI 1.9–12.8), p = 0.001) and neurovascular contact with morphological changes (OR 2.5 (CI 1.1–6.0), p = 0.036). Significantly more women (12/62 = 19%) than men (2/53 = 4%) had a failed outcome, p = 0.019. The most frequent major complications were permanent hearing impairment (10%), permanent severe hypoesthesia (7%), permanent ataxia (7%), and stroke (6%). Most patients (94%) recommend surgery to others.ConclusionMicrovascular decompression is an effective treatment for classical and idiopathic (only patients with a neurovascular contact) trigeminal neuralgia with a high chance of a long-lasting effect. The chance of an excellent outcome was highest in men and in patients with classical trigeminal neuralgia. Complications are relatively frequent warranting thorough patient evaluation and information preoperatively.Trial registrationClinical.trials.gov registration no. NCT04445766.

The practical limits of high-quality magnetic resonance imaging for the diagnosis and classification of trigeminal neuralgia

BackgroundNeurovascular compression (NVC) has been the primary hypothesis for the underlying mechanism of classical trigeminal neuralgia (TN). However, a substantial body of literature has emerged highlighting notable exceptions to this hypothesis. The purpose of this study is to assess the reliability and diagnostic accuracy of high resolution, high contrast MRI-determined neurovascular contact for TN. MethodsWe performed a retrospective, randomized, and blinded parallel characterization of neurovascular interaction and diagnosis in a population of TN patients and controls using four expert reviewers. Performance statistics were calculated, as well as assessments for generalizability using shuffled bootstraps. ResultsFair to moderate agreement (ICC: 0.32–0.68) about diagnosis between reviewers was observed using MRIs from 47 TN patients and 47 controls. On average reviewers performed no better than chance when diagnosing participants, with an accuracy of 0.57 (95% CI 0.40, 0.59) per patient. ConclusionWhile MRI is useful in determining structural causes in secondary TN, expert reviewers do no better to only slightly better than chance with distinguishing TN with MRI, despite moderate agreement. Further, the causal role of NVC for TN is not clear, limiting the applicability of MRI to diagnose or prognosticate treatment of TN.

Vascular loops in cerebellopontine angle in patients with unilateral idiopathic sudden sensorineural hearing loss: Evaluations by three radiological grading systems.

ObjectiveWe aimed to investigate the impact of the position, configuration and neurovascular contact of the anterior inferior cerebellar artery (AICA) in cerebellopontine angle (CPA) and internal auditory canal (IAC) on the clinical features of patients with unilateral idiopathic sudden sensorineural hearing loss (ISSNHL).MethodsOne hundred and thirty‐six patients with unilateral ISSNHL were enrolled. All patients received detailed history inquiry and standard treatments. Pure tone audiometry and magnetic resonance imaging (MRI) of CPA‐IAC were performed. The MRI findings of both ears were evaluated by the Chavda, Gorrie and Kazawa systems. The association between radiological findings and clinical data were analyzed.Results(1) No significant interaural difference in the position, configuration and neurovascular contact of AICA was observed. (2) There was no significant association between the AICA loop and concomitant vertigo or pre‐treatment audiometric configuration in the affected ear. (3) Concomitant tinnitus seemed to be affected by the configuration of AICA categorized by Kazawa system, while the Chavda and Gorrie classification of AICA loop was unassociated with tinnitus. (4) Hearing outcomes were not compromised by the position or configuration of AICA based on the Chavda and Kazawa systems. Patients with Gorrie type B tended to have better hearing recovery than those with type C.ConclusionsIn patients with ISSNHL, the position, configuration and neurovascular contact of AICA in the CPA‐IAC were unassociated with the side of hearing loss, audiometric configurations, or concomitant vertigo. The neurovascular contact graded by Gorrie system might be associated with hearing outcomes.

A single centre case series of microvascular decompression surgery for classical trigeminal neuralgia: functional outcomes and report of a unique conflict

BackgroundMicrovascular decompression surgery for trigeminal neuralgia is now considered the benchmark surgical procedure for intractable trigeminal neuralgia of any variety. The objective of this study is to share our experience in managing classical trigeminal neuralgia with microvascular decompression surgery looking into both immediate and late functional outcomes at 3 and 6 months post op. We also report a unique case of trigeminal neuralgia due to a tributary of the petrosal vein passing through the substance of the trigeminal nerve itself at its root entry zone.ResultsThis study included 20 patients; it showed that microvascular decompression surgery of the trigeminal nerve is an effective method for treatment of classic trigeminal neuralgia (p value < 0.001). The trigeminal root was compressed by the superior cerebellar artery in 75% of patients. A vein contributed to the compression in 45% of patients and was the only compressing vessel in 15%.ConclusionMicrovascular decompression surgery is the treatment of choice in patients with medically refractory trigeminal neuralgia, unless their general condition prohibits it. It’s also worth noting that the normal anatomy of the veins in this region is quite variable and the venous structures causing a neurovascular contact are more or less inconsistent. To the best of our knowledge and despite the wide range and progress in microvascular decompression surgery for trigeminal neuralgia, this is the first reported case in the literature for a neurovascular conflict caused by a vein passing through the trigeminal nerve itself.

Significance of different offending vessels and development of a potential screening tool for trigeminal neuralgia.

This study was performed amongst trigeminal neuralgia (TN) patients with neurovascular contact (NVC) to 1) investigate the association of the demographic and radiologic factors/variables with TN occurrence, and 2) develop a screening tool for TN/TN-affected nerves based on the factors/variables associated with it. Eighty-five TN patients were recruited, and 121 trigeminal nerves with NVC were derived from them. Based on MRI sequences, including balanced turbo field echo and enhanced T1 high-resolution isotropic volume excitation, radiologic factors/variables for each nerve, from the offending vessel to the presence of nerve displacement, were identified by a neuroradiologist and a neurosurgeon. Demographic and clinical data were obtained from clinical notes. Logistic regression was performed to assess the association of the factors/variables with TN occurrence (i.e., affected vs. unaffected nerves). Three factors/variables were significantly (p<0.05) associated with TN occurrence amongst patients with NVC: nerve laterality, vertebral artery (VA) involvement, and the presence of nerve displacement. The nerves with VA involvement, those on the right side, and those with nerve displacement exhibited a significantly higher likelihood/odd of being affected by TN, compared to those without VA involvement, those on the left side, and those without nerve displacement, respectively. Based on these factors/variables, a screening tool/nomogram with acceptable accuracy was established (C-statistic/AUC = 0.80). This study revealed an association of the three radiologic factors/variables with TN occurrence. A screening tool for TN/TN-affected nerves was established based on them. The findings may lay a foundation for an improvement of the diagnosis and clinical management of TN. • VA involvement and nerve displacement could be identified using MRI, and are significantly associated with TN occurrence. • A potential objective screening tool/nomogram for TN/TN-affected nerves could be established based on the three radiologic factors/variables: VA involvement, the presence of nerve displacement, and nerve laterality. • The screening accuracy of the tool/nomogram is acceptable as the C-statistic is 0.80.