Neurovascular Conflict Research Articles

Assessing trigeminal microstructure changes in patients with classical trigeminal neuralgia

Introduction. The crucial role of neuro-vascular conflict (NVC) in trigeminal neuralgia (TN) is getting increasingly challenged. Microstructural changes can be assessed using fractional anisotropy (FA) in diffusion tensor images (DTI).
 Objective. To evaluate usefulness of FA in brain MRI with DTI for TN lateralization assessment.
 Materials and methods. The study included 51 patients with classical TN divided into two groups: neurosurgical intervention free, post radiofrequency ablation (RFA), and a control group (patients without facial pain). All the patients were tested for NVC with FIESTA (Fast Imaging Employing Steady State Acquisition) brain MRI at 3Т. Difference in thickness of trigeminal roots on the intact and symptomatic sides was assessed for each group. The findings were compared to those in the control group. The MRI protocol was supplemented with DTI. The FA difference in thickness of the intact and symptomatic roots (∆FA) was calculated for each study group to assess microstructural root changes. The results were compared to those in the control group.
 Results. In trigeminal root DTIs, ∆FA over 0.075 [0.029; 0.146] is statistically significant to establish NVC-associated microstructural changes on the symptomatic side in patients without any past surgeries (p = 0,030). In patients with a history of trigeminal ganglion RFA, statistically significant (p = 0.026) thinned symptomatic trigeminal root (difference in thickness of trigeminal roots over 0.45 cm [0.4; 0.6]) was found as compared to that of the control patients.
 Conclusion. FA may be used as a quantitative demyelination biomarker in clinical TN. Trigeminal ganglion RFA leads to hypotrophy throughout the trigeminal nerve root.

Microvascular decompression for young onset primary trigeminal neuralgia: a single-center experience

This study aims to explore the causes of primary young onset trigeminal neuralgia (TN) and the clinical outcomes of these patients. From May 2015 to December 2020, 19 primary TN patients with onset age under 30years underwent microvascular decompression (MVD) in Nanjing Drum Tower Hospital. In this study, the clinical characteristics, surgical outcomes, and postoperative complications of these patients were analyzed retrospectively. Of the 19 patients, 5 were males and 14 were females, and the pain was located on the right side in 10 cases (52.6%). Vascular compression was observed in 17 patients, including 14 cases of superior cerebellar artery (SCA) alone, 2 cases of superior petrosal vein (SPV) alone, and 1 case of SCA and SPV combined. Two patients had no neurovascular conflict, and nerve combing was performed. After surgery, 18 patients got immediate pain relief; 1 patient improved but still had occasional pain. With a mean follow-up of 42.7 ± 22.3months, one patient was found to have a relapse 45months after MVD. Surgical complications including mild facial numbness in two patients and hearing impairment in one patient. Neurovascular compression is the main cause of young onset primary TN, and the most commonly encountered vascular was SCA. MVD is a safe and effective treatment for these patients.

Neurovascular conflict and sudden unilateral sensorineural hearing loss: coincidence or coexistence?

To study the association between neurovascular conflict (NVC) of the 8thcranial nerve (CN8) and unilateral sudden sensorineural hearing loss SSNHL (SSNHL). A systematic literature search of "MEDLINE" via "PubMed," "Embase," and "Google-Scholar" was conducted. Meta-analysis of pooled data was performed for NVC prevalence of SSNHL affected ears versus controls. The literature search identified 941 publications, of which, 9 included in qualitative synthesis (1030 ears) and 5 in quantitative synthesis (484 ears). NVC was as prevalent as 0.8-69% for affected ears and as 19-57% for controlled ears. No association between MRI protocol and NVC prevalence was proved. An odds ratio of 1.05 (95% confidence interval = 0.79-1.39) was calculated for association of NVC in unilateral SSNHL ears versus controls. The prevalence of NVC of CN8 in unilateral SSNHL affected ears is not significantly bigger than controls. Hence, NVC of CN8 is probably NOT associated with unilateral SSNHL.

Clinical characteristics of pain in patients with trigeminal neuralgia: data from a neurosurgical clinic

Among the pain syndromes caused by damage to cranial nerves, trigeminal nerve pathology occupies the main place. Trigeminal neuralgia is an exhausting condition characterized by acute shooting recurrent pain in the face. However, according to modern classification of facial pain types, there is also a distinction made for the second type of neuralgia, in which the mentioned pain alternates with dull, burning pain in the area of trigeminal nerve innervation. Numerous clinical and diagnostic criteria which can influence the results of surgical treatment of trigeminal neuralgia are being actively studied. However, the data varies both in terms of the number of criteria considered and the nature of the study, as well as the research outcomes.Objective ‒ to determine the demographic, clinical, and anatomical characteristics of patients with classical trigeminal neuralgia upon their admission in the neurosurgical ward for microvascular decompression of the trigeminal nerve.Materials and мethods. A retrospective analysis of medical data from 92 patients with trigeminal neuralgia, who were admitted to the Regional Clinical Center of Neurosurgery and Neurology from 2011 to 2023 was performed. The data included: patient's gender and age, type of neuralgia according to K. Burchiel and colleagues' classification (2009), involvement of trigeminal nerve branches, duration of pain prior to hospitalization, medication for conservative therapy and its dosage. Results. Trigeminal neuralgia most commonly affects elderly patients. This may be associated with systemic atherosclerotic vessel damage, leading to increased irritation by a denser vessel wall. Another cause of late disease manifestation may be gradual demyelination in the vicinity of the neurovascular conflict. Women are more likely to be affected than men. Right-sided trigeminal nerve involvement and the involvement of lower and upper jaw branches are more characteristic, with pain more frequently being paroxysmal in nature. In seven out of ten patients, the cause of neurovascular conflict is an artery, with the upper cerebellar artery being the most typical conflict.Conclusions. Demographic and clinical-diagnostic indicators vary among patients with trigeminal neuralgia. There are numerous variables that can influence the long-term effects of conservative and surgical treatment in patients with trigeminal neuralgia. A comprehensive assessment of these factors can identify a group of patients who are likely to have the most successful long-term treatment outcomes for trigeminal neuralgia.

COCHLEAR SYNAPTIC TINNITUS – CAN IT BE CURED

Objective: The objective of this study was to determine the tinnitus demography, etiology, treatment options, and their response in a Tertiary Care Teaching Hospital. Methods: The study was conducted on patients above 21 and below 80 years who presented with tinnitus and hearing loss to ENT outpatient department (OPD) of Dr. Patnam Mahender Reddy Institute of Medical Sciences (PMRIMS), Chevella from May 2019 to February 2020. To identify the cause of tinnitus, the following investigations were considered: Pure-tone audiogram; tympanometry; blood investigations, color Doppler ultrasonography to evaluate blood flow disturbance in the vertebral and basilar artery, middle/inner ear high-resolution computerized tomography scan (CT), and, in the case of suspicion of vestibular Schwannoma or neurovascular conflict, magnetic resonance imaging/angio-CT (MRI/Angio-CT) was done. Results: Among the patients attending ENT OPD with tinnitus, those with idiopathic cochlear synaptic tinnitus were identified, and 100 were selected and treated with various modalities of pharmacological treatment available for the same found that no specific drug was 100% effective in relieving the symptom. Conclusion: The present study treated tinnitus of cochlear origin with various drugs and followed up with patients for 3 months. They were assessed with tinnitus sample case history questionnaire, and the study concluded that no pharmacological treatment effectively treats cochlear synaptic tinnitus.

Sacrifice or preserve the superior petrosal vein in microvascular decompression surgery: a systematic review and meta-analysis.

In microvascular decompression (MVD) surgery through the retrosigmoid approach, the surgeon may have to sacrifice the superior petrosal vein (SPV). However, this is a controversial maneuver. To date, high-level evidence comparing the operative outcomes of patients who underwent MVD with and without SPV sacrifice is lacking. Therefore, this study sought to bridge this gap. The authors searched the Medline and PubMed databases with appropriate Medical Subject Heading (MeSH) terms and keywords. The primary outcome was vascular-related complications; secondary outcomes were new neurological deficit, cerebrospinal fluid (CSF) leak, and neuralgia relief. The pooled proportions of outcomes and OR (95% CI) for categorical data were calculated by using the logit transformation and Mantel-Haenszel methods, respectively. Six studies yielding 1143 patients were included, of which 618 patients had their SPV sacrificed. The pooled proportion (95% CI) values were 3.82 (0.87-15.17) for vascular-related complications, 3.64 (1.0-12.42) for new neurological deficits, 2.85 (1.21-6.58) for CSF leaks, and 88.90 (84.90-91.94) for neuralgia relief. The meta-analysis concluded that, whether the surgeon sacrificed or preserved the SPV, the odds were similar for vascular-related complications (2.5% vs 1.5%, OR [95% CI] 1.01 [0.33-3.09], p = 0.99), new neurological deficits (1.2% vs 2.8%, OR [95% CI] 0.55 [0.18-1.66], p = 0.29), CSF leak (3.1% vs 2.1%, OR [95% CI] 1.16 [0.46-2.94], p = 0.75), and neuralgia relief (86.6% vs 87%, OR [95% CI] 0.96 [0.62-1.49], p = 0.84). SPV sacrifice is as safe as SPV preservation. The authors recommend intentional SPV sacrifice when gentle retraction fails to enhance surgical field visualization and if the surgeon encounters SPV-related neurovascular conflict and/or anticipates impeding SPV-related bleeding.

Long-term results of microvascular decompression with video endoscopy in the treatment of patients with atypical trigeminal neuralgia

Background: The incidence of atypical trigeminal neuralgia (aNTN) varies from 1 to 7 per 100,000 population per year. The main cause of its development is compression of the trigeminal nerve (TN) root by a vein and/or artery in the cerebellar cistern. To date, the final tactics of treatment for patients with aNTN has not been specified. The effectiveness of conservative methods of therapy does not exceed 50%.
 The aim of this study was to evaluate the results of microvascular decompression using video endoscopy in the treatment of patients with atypical trigeminal neuralgia.
 Methods: In the period from 2014 to 2021, 34 patients with aNTN were operated on, of which 18 (53%) patients had neuropathic pain (more than 4 points on the DN4 scale), and 15 (44%) patients had transformation of classical trigeminal neuralgia into atypical neuralgia. The conservative therapy (carbamazepine, gabapentin, pregabalin), administered to all the patients in the preoperative period, was not accompanied by a significant relief of pain syndrome. The maximum intensity of pain upon admission to the hospital was, according to the visual analog scale (VAS), 10 points, according to the BNI (Barrow Neurological Institute) Pain Intensity Scale V (severe, persistent pain). All the patients underwent microvascular decompression of the trigeminal nerve root with the use of Teflon; in 12 (35%) patients, in addition to microscopy, video endoscopy was used. The average follow-up period after the surgery was 3.41.7 years (from 1 to 5 years).
 Results: In all (100%) patients, the pain was completely eliminated (BNI I) after the surgery. A total five-year excellent and good outcome of the disease on the J. Miller and BNI scale (I -II) was noted in 80% (n=27) of patients with aNTN. The risk of pain recurrence after microvascular decompression was 14% (n=3) in the first three years, and 34% (n=4) after 5 years. The use of video endoscopy made it possible to identify the blood vessels compressing the root of the trigeminal nerve with a minimal displacement of the cerebellum and cranial nerves when visualizing the neurovascular conflict.
 Conclusion: The microvascular decompression method with video endoscopy is effective in the treatment of patients with aNTN.

Could recurrent painful ophthalmoplegic neuropathy be caused by a neurovascular conflict?: A case report

Objective: Describe and discuss a typical case with recurrent painful ophthalmoplegic neuropathy (RPON), and demonstrate a likely extrinsic compression of the sixth cranial nerve by a vascular loop. Background: RPON is a rare, but well-known entity, characterized by attacks of ophthalmoplegia associated with ipsilateral headache. The etiology is unknown, but a neurovascular conflict (NVC) has been suggested as a cause. Method: A 62-year-old woman presented in the emergency department with a horizontal diplopia that developed a few hours after the onset of a left temporal headache. In the past she had presented to the clinic with the same problem several times. She had been thoroughly examined, but no cause had been found. The symptoms had resolved by themselves. In addition to a classic finding in RPON, gadolinium enhancement and thickening of a cranial nerve, the new MRI scanning detected an NVC. Herein we discuss the relevance of this finding. Conclusion: A neurovascular conflict causing inflammatory demyelination of a single cranial nerve and relapsing remitting painful ophthalmoplegic neuropathy is an alluring idea. However, it is hard to conceive theoretically, and more reported cases with compelling data are needed to give credibility to such an idea.

Vascular decompression in the treatment of trigeminal neuralgia in dolichoectated vertebrobasilar artery

Dolichoectasia of vertebrobasilar artery is an uncommon and rare cause of trigeminal neuralgia. The article presents a case of successful treatment of a patient with trigeminal neuralgia caused by vertebrobasilar dolichoectasia. The technical complexity of the operation is due to the rigidity and tortuosity of a large-caliber vessel with perforating branches leading to the brain stem and limited space in the cerebellopontine angle. The implantation of Teflon wool in areas of neurovascular conflict is an effective surgical aid for complete elimination of trigeminal neuralgia while maintaining the anatomical integrity of the nerve structures and minimizing the risk to the patient.

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.

Diagnosis of neurovascular conflict Sindou grade 1 in patients with trigeminal neuralgia using diffusion-tensor MRI

Diagnosis of neurovascular conflict Sindou grade 1 in patients with trigeminal neuralgia using diffusion-tensor MRI

CSF neuron-specific enolase as a biomarker of neurovascular conflict severity in drug-resistant trigeminal neuralgia: a prospective study in patients submitted to microvascular decompression.

Although neurovascular conflict (NVC) is the most widely accepted cause of trigeminal neuralgia (TN), few articles have analyzed molecular and biochemical mechanisms underlying TN. In the present study, we dosed neuron-specific enolase (NSE) on serum and CSF samples of 20 patients submitted to microvascular decompression (MVD) and correlated these findings with the type of NVC. Blood samples were obtained preoperatively and 48 h after MVD. CSF from trigeminal cistern was intraoperatively obtained. NSE levels were measured using the Diasorin kit (LIAISON®NSE). NVC was classified as "contact" or "trigeminal nerve distortion/indentation" or "trigeminal root atrophy" based on MRI and intraoperative findings. Clinical outcome was measured by acute pain relief (APR) and Barrow Neurological Institute (BNI) scale at last available follow-up (FU; 6.40 ± 5.38 months). APR was obtained in all patients. A statistically significant BNI reduction was obtained at latest FU (p < 0.0001). Serum NSE levels significantly decreased following MVD (from 12.15 ± 3.02 ng/mL to 8.95 ± 2.83 ng/mL, p = 0.001). The mean CSF NSE value was 48.94 ng/mL, and the mean CSF/serum NSE rate was 4.18 with a strong correlation between these two variables (p = 0.0008). CSF NSE level in "trigeminal root atrophy" group was significantly higher compared to "contact" (p = 0.0045) and "distortion/indentation" (p = 0.010) groups. NSE levels seem to be related to the etiopathology and severity of NVC. A significant reduction of serum NSE levels could be related to the resolution of the NVC and clinical TN improvement.

Analysis of the causes of the occurrence and treatment results of sudden hearing loss/deafness in the own material.

The aim of the study was to analyze the causes of the occurrence and treatment results of sudden hearing loss / deafness in own material. The tests were performed in 64 women aged 10-89 years and 70 men aged 18-85 years, who were treated in the Department of Otolaryngology due to sudden hearing loss / deafness in 2011-2020. A retrospective analysis was carried out on the basis of the data contained in the medical documentation, taking into account: gender, age of patients, type of symptoms, establishing the circumstances and possible causes of the appearance of symptoms, audiological and imaging tests, the cause of the sudden hearing loss / deafness and applied treatment. In the conducted research it was found that sudden hearing loss / deafness was the most common in women and men in the age range of 51-60 years and 61-70 years. Sudden hearing loss/ deafness was accompanied by the following symptoms in both women and men: tinnitus in 48,4% and 74,3%, tinnitus and vertigo in 28,1% and 14,3%, and vertigo in 6,3% and in 1,4%. In own research, the most common cause of sudden hearing loss/deafness in women and men was respectively: idiopathic cause in 43,8% and 40,0%, infectious in 18,8%, vascular in 12,4% and 12,9%, and neurovascular conflict (included separately) in 12,4% and 12,9%, while in men the acoustic trauma should also be mentioned in 18,5%. The best results in the treatment of sudden hearing loss / deafness on a three-point scale, which depends on the treatment method used, both in women and men, i.e. complete relief of symptoms obtained after the use of vascular drugs with steroid therapy and hyperbaric oxygen therapy - in 25,0% and 22,9%, partial relief of symptoms occurred after vascular treatment with steroid therapy - in 28,1% and 37,2%. Sudden hearing loss / deafness in both women and men was accompanied by tinnitus, tinnitus and vertigo and vertigo at the same time. In own research the most common cause of sudden hearing loss / deafness in both women and men was: idiopathic, infectious, vascular and neurovascular conflict. The best emergency treatment outcomes of sudden hearing loss / deafness according to a three-level scale, depending on the applied method of treatment, both in women and men, i.e. complete relief of symptoms was obtained after the use of vascular drugs with steroid therapy and hyperbaric oxygen therapyKey words: causes, occurrence, treatment results, sudden hearing loss / deafnes.

Factors Predicting Cerebrospinal Fluid Leaks in Microvascular Decompressions: A Case Series of 1011 Patients.

Microvascular decompression (MVD) using a retrosigmoid approach is a highly effective, open-surgical procedure for neurovascular conflict in the posterior fossa, although there is a risk of postoperative cerebrospinal fluid (CSF) leak. To identify factors associated with postoperative CSF leakage after MVD. We retrospectively reviewed all patients who underwent MVDs at our institution from 2007 to 2020. Patient demographics, clinical diagnoses, and procedural characteristics were recorded and compared. Factors leading to CSF leak were analyzed using χ 2 , univariate, and multivariate regression. Of 1011 patients who underwent MVDs, 37 (3.7%) presented with postoperative CSF leaks. In univariate analysis, the use of Cranios/Norian to obliterate the air cells was protective against CSF leak ( P = .01). Craniotomies ( P = .002), the use of dural substitutes such as Durepair ( P = .04), dural onlays such as DuraGen ( P = .04), muscle/fascia ( P = .03), and titanium mesh cranioplasty >5 cm ( P = .03) were associated with CSF leak. On multivariate analysis, only the presence of craniotomies ( P = .04) and nonprimary dural closure ( P = .03) were significant risk factors for CSF leak. When excluding the 34 (3.4%) patients who underwent a craniotomy, the lack of primary dural closure still remained significantly associated with postoperative CSF leak ( P = .04). Our results represent one of the largest series of posterior fossa surgeries for a uniform indication in North America. Our study demonstrates increased risk for postoperative CSF leak when craniotomies are performed and when primary dural closure is not established. Given the small sample of patients who received a craniotomy, however, future studies corroborating this finding should be performed.

Clinical outcome after microvascular decompression for trigeminal neuralgia: a systematic review and meta-analysis.

Microvascular decompression (MVD) is considered an effective treatment for trigeminal neuralgia (TN). However, the anatomical and clinical variables associated with a better outcome are not fully examined. The authors performed a systematic review and meta-analysis of the literature investigating the immediate and long-term clinical results of MVD for TN, and the impact of the anatomical features of the neurovascular conflict on the outcome. The systematic search of three databases was performed for studies published between January 1990 and November 2021. PRISMA guidelines were followed. Random-effects meta-analysis was used to pool the analyzed outcomes, and random-effect meta-regression was used to examine the association between the effect size and potential confounders. A funnel plot followed by Egger's linear regression was used to test publication bias. A total of 9 studies were included in this analysis, including 2102 patients with trigeminal neuralgia. The immediate post-operative rate of BNI I was 82.9%, whereas surgical failure (BNI IV-V) was reported in approximately 2.6% of patients. CSF leak was the most common postoperative complication (2.4%). The rate of BNI I at last follow up was 64.7% (p < 0.01), showing a significant negative correlation after multiple meta-regression with the rate of patients with isolated venous conflict (p < 0.01). On the other hand, the evidence of an arterial conflict proved is positive association with a favorable outcome (p < 0.01). At the last follow-up, BNI IV-V was reported in 19.2% (95% CI 8.9-29.5%, p < 0.01, I2 = 97.3%). This meta-analysis confirms the safety and efficacy of MVD for TN. The occurrence of serious postoperative complications is very low. The long-term outcome is associated with the type of vascular structure involved, being pure venous conflict associated with a higher risk of surgical failure. These findings should be considered when planning surgery for patients with TN.

3D-visualization of neurovascular conflict in patients with classical trigeminal neuralgia

Introduction. MRI is well-recognized as a leading method of neurovascular conflict (NVC) evaluation in patients with classical trigeminal neuralgia (CTN). NVC is regarded as the cause of the development of deformity, atrophy, or dislocation of the trigeminal nerve root. Currently, the number of worldwide publications concerning the analysis of NVC 3D-reconstruction for the diagnosis of cranial nerve hyperfunction syndromes is still small. The aim of the study was to evaluate the efficacy of NVC 3D-visualization for CTN diagnosis compared to conventional examination protocols. Materials and methods. From 2018 to 2020, 30 patients with CTN who underwent 3D-visualization of the NVC as a preoperative examination were involved in prospective nonrandomized study. T-2 3D (FIESTA), 3D-TOF and T1 FRSGR were utilized for 3D rendering (Fusion protocol). The obtained data were compared only FIESTA-based «prediction» of NVC and with intraoperative findings. Results. FIESTA-only prediction was effective in 93 %, and Fusion protocol — in 97 % of arterial type of NVC cases. Fusion protocol showed its supremacy in detecting venous type of compression. Average efficacy of FIESTA-only prediction was 84 %, whereas Fusion protocol showed 97 % correlation with intraoperative findings. Conclusion. Fusion protocol allows fast detection of NVC, its type and localization (not only at the REZ of the fifth nerve but also at its cisternal portion). It makes possible tracing the course of the compressing vessel and assess the «convenience» of decompressing the TN root, taking into account the spatial relationship of the brainstem, vessels of the cerebellopontine angle and cranial nerves. Unlike FIESTA-only scanning, 3D-rendering also offers a possibility of preoperative simulation of microvascular decompression by recreating intraoperative view with precise details. Patient examination with FIESTA-only scanning is inferior to the «extended» algorithm for NVC diagnosis and does not have these capabilities.

Delayed pain relief in patients with trigeminal neuralgia following microvascular decompression: A single-central retrospective study.

Compared to hemifacial spasm after microvascular decompression (MVD), delayed relief (DR) rarely occurs in patients with trigeminal neuralgia (TGN). To analyze the characteristics of post-MVD DR in TGN patients to provide useful clues for the clinical differential diagnosis of postoperative DR. The clinical data of all patients with TGN who underwent MVD in our center from January 1, 2016, to December 31, 2020, were reviewed retrospectively. In 272 TGN MVD patients, DR occurred in nine patients (3.3%) during the follow-up periods of 1-6 years. During surgery, all nine DR-TGN patients were identified as having neurovascular conflicts (NVCs), involving the offending artery (OA) in eight patients (two OAs in two patients) and both an artery and a vein in the other patient. The compression site was near the root entry zone (REZ) in most DR patients (7/9). Delayed relief was relieved in seven patients within 5 days after surgery and within 30 days in the other two patients. No recurrence or serious complications were observed within the mean 4 (1-6)-year follow-up duration. Delayed relief rarely occurs in TGN patients after MVD. Neurovascular conflicts located at the REZ and NVC of grade III may be two important factors contributing to DR in TGN patients. Delayed relief may occur when the pain gradually improves after the operation and responds effectively to a small dose of carbamazepine. The recurrence rate of TGN seems even lower in such patients.

Magnetic resonance imaging evaluation of masticatory muscle changes in patients with primary trigeminal neuralgia before microvascular decompression.

Primary trigeminal neuralgia (PTN) is characterized by chronic neuropathic pain. There are few studies exploring masticatory muscle changes in patients with PTN. This study evaluated the changes in the masticatory muscles using magnetic resonance imaging (MRI) and the predictive factors of masticatory muscle changes in patients with PTN. The radiologic outcomes of 52 patients with PTN and 58 healthy adults were evaluated. The temporalis, lateral pterygoid, medial pterygoid, and masseter muscles were assessed using MRI. Atrophy and edema of the masticatory muscles were noted. Multivariate analyses were conducted to identify factors associated with masticatory muscle atrophy. Among the PTN group, the right side (61.5%) and mandibular branch (53.9%) were the most affected. Muscle atrophy of the temporalis (P < .001), medial pterygoid (P = .016), lateral pterygoid (P = .031), and masseter (P = .001) were significantly higher in the PTN group than in the control group. Lateral pterygoid edema was significantly higher in the PTN group (P < .001). However, no significant difference was found in the temporalis and masseter edema between the two groups. Logistic regression analysis demonstrated that neurovascular conflict (NVC) significantly predicted mastication muscle atrophy (P = .037). Patients with PTN had higher rates of masticatory muscle atrophy and edema. The assessment of NVC may be a preoperative imaging biomarker to predict atrophy in PTN.

The Role of Preoperative Magnetic Resonance Imaging in Assessing Neurovascular Compression Before Microvascular Decompression in Trigeminal Neuralgia

Preoperative magnetic resonance imaging (MRI) is a standard component of the preoperative clinical workup for patients before microvascular decompression (MVD). However, its ability to accurately exclude neurovascular compression of the trigeminal nerve is not well understood. We retrospectively reviewed 1020 patients with available preoperative MRI data before microvascular decompression. General patient demographics and clinical characteristics were collected for each case. We recorded both evidence of neurovascular conflict on preoperative MRI radiology notes and intraoperative compression from operative notes. Sensitivity, specificity, positive predictive value, and negative predictive value were determined for general MRI, high-resolution MRI, and non-high resolution. Overall, preoperative MRI before MVD showed a sensitivity of 75.8%, specificity of 65.8%, positive predictive value of 92.4%, and negative predictive value of 33.3% in predicting neurovascular compression of the trigeminal nerve. In particular, MRI was unable to identify 21.0% cases of sole arterial compression, 42.5% cases of sole venous compression, and combined arterial and venous compression in 18.5% of cases. A total of 958 patients (93.9%) underwent high-resolution preoperative MRI with skull base sequences. This imaging showed a sensitivity of 75.6%, specificity of 66.9%, positive predictive value of 92.5% and a negative predictive value of 33.4% in predicting trigeminal nerve neurovascular compression. Non-high-resolution MRI showed a sensitivity of 78.8%, specificity of 50.0%, positive predictive value of 89.1%, and negative predictive value of 31.3%. The negative predictive values of general, high-resolution, and non-high-resolution MRIs were all <50%. Preoperative MRI may offer a high predictive value for neurovascular conflict and should be part of the standard preoperative care workup for patients with trigeminal neuralgia. However, lack of neurovascular conflict on preoperative imaging is not sufficient to exclude patients from undergoing MVD.

Clinical Outcome of Partial Sensory Rhizotomy in Negative-Exploration Trigeminal Neuralgia and Technical Nuances

Background: Microvascular decompression is considered to be a potential treatment for most trigeminal neuralgia cases with obvious neurovascular conflict. Partial sensory rhizotomy (PSR) is an alternate option in cases of negative investigation for neurovascular conflict, although its effectiveness and technical complexity are still being debated. Objective: To evaluate the therapeutic efficacy of PSR following negative-exploration trigeminal neuralgia (NETN) in terms of pain control, adverse effects from sensory fiber destruction, and patient satisfaction in the short-term or after 1 month, and in the long-term or after 12 months. In addition, technical nuances were highlighted to mitigate the negative effects of PSR. Materials and Methods: The present study enrolled 27 NETN patients, and all were operated by the same neurosurgeon. The patients underwent surgery via a keyhole retromastoid technique, with extensive exploration for any possible intraoperative neurovascular conflict. A modified PSR approach was used to operate on these negative exploration cases, and this entailed cutting fewer than 1/5 of the trigeminal sensory fibers. The short-term or within one month, and long-term or after one-year intervals were used to track all instances. The therapeutic efficacy of employing pain score and subjective sensation in terms of pain control, adverse consequences from sensory fiber destruction, and patient satisfaction were investigated. Results: Eighty-five point two percent of patients reported excellent pain control following PSR, in terms of both pain score and total pain alleviation. Despite having their trigeminal nerve fibers severed, not all of the patients experienced numbness, and 45% of patients recovered to some extent on their own within a year. Only 13% of patients had Anesthesia Dolorosa in the present trial, which could be attributable because only 1/5 of the trigeminal nerve fibers were severed. There was no relationship between pain distribution and pain alleviation efficacy before and after PSR. When PSR was effective, most patients should notice an improvement within a month of the surgery. Conclusion: For patients with negative exploration following keyhole suboccipital craniectomy, PSR proved to be therapeutic and effective in alleviating trigeminal neuralgic pain. The majority of the patients can tolerate the minor side effects from minute nerve destruction well, particularly numbness, which partially resolves on its own with time. Keywords: Negative exploration; Trigeminal neuralgia; Microvascular decompression; Partial sensory rhizotomy; Efficacy