Sensitivity of magnetic resonance tomographic angiography for detecting the degree of neurovascular compression in trigeminal neuralgia

Awake neurosurgery: Advancements in microvascular decompression for trigeminal neuralgia

Background

The treatment landscape for trigeminal neuralgia (TN) involves various surgical interventions, among which microvascular decompression (MVD) stands out as highly effective. While MVD offers significant benefits, its success relies on precise surgical techniques and patient selection. In addition, the emergence of awake surgery techniques presents new opportunities to improve outcomes and minimize complications associated with MVD for TN.

Methods

A thorough review of the literature was conducted to explore the effectiveness and challenges of MVD for TN, as well as the impact of awake surgery on its outcomes. PubMed and Medline databases were searched from inception to March 2024 using specific keywords "Awake Neurosurgery," "Microvascular Decompression," AND "Trigeminal Neuralgia." Studies reporting original research on human subjects or preclinical investigations were included in the study.

Results

This review highlighted that MVD emerges as a highly effective treatment for TN, offering long-term pain relief with relatively low rates of recurrence and complications. Awake surgery techniques, including awake craniotomy, have revolutionized the approach to MVD, providing benefits such as reduced postoperative monitoring, shorter hospital stays, and improved neurological outcomes. Furthermore, awake MVD procedures offer opportunities for precise mapping and preservation of critical brain functions, enhancing surgical precision and patient outcomes.

Conclusion

The integration of awake surgery techniques, particularly awake MVD, represents a significant advancement in the treatment of TN. Future research should focus on refining awake surgery techniques and exploring new approaches to optimize outcomes in MVD for TN.

Analyzing the risk factors of unilateral trigeminal neuralgia under neurovascular compression

Background

This study aimed to explore the risk factors and potential causes of unilateral classical or idiopathic trigeminal neuralgia (C-ITN) by comparing patients and healthy controls (HCs) with neurovascular compression (NVC) using machine learning (ML).

Methods

A total of 84 C-ITN patients and 78 age- and sex-matched HCs were enrolled. We assessed the trigeminal pons angle and identified the compressing vessels and their location and severity. Machine learning was employed to analyze the cisternal segment of the trigeminal nerve (CN V).

Results

Among the C-ITN patients, 53 had NVC on the unaffected side, while 25 HCs exhibited bilateral NVC, and 24 HCs showed unilateral NVC. By comparing the cisternal segment of CN V between C-ITN patients on the affected side and HCs with NVC, we identified the side of NVC, the compressing vessel, and certain texture features as risk factors for C-ITN. Additionally, four texture features differed in the structure of the cisternal segment of CN V between C-ITN patients on the unaffected side and HCs with NVC.

Conclusion

Our findings suggest that the side of NVC, the compressing vessel, and the microstructure of the cisternal segment of CN V are associated with the risk of C-ITN. Furthermore, microstructural changes observed in the cisternal segment of CN V on the unaffected side of C-ITN patients with NVC indicate possible indirect effects on the CN V to some extent.

Shape deformations of the basal ganglia in patients with classical trigeminal neuralgia: a cross-sectional evaluation

INTRODUCTION

Despite the involvement of subcortical brain structures in the pathogenesis of classic trigeminal neuralgia (CTN), the details of morphological abnormalities of basal ganglia to this disorder are still unknown. This study aimed to investigate potential changes in terms of volume and shape of subcortical regions in patients with CTN.

METHODS

Forty-eight patients with CTN and 46 matched healthy subjects were recruited in the study. The whole-brain T1 anatomical data was acquired at a 3.0 Tesla scanner using a fast spoiled gradient recalled sequence (FSPGR). Vertex-wise analysis was applied to detect the alterations of volume and shape in each subcortical region in the patients with CTN compared to healthy controls. The relationships of morphological abnormalities in subcortical structures to the severity of orofacial pain and the affective disturbance in the patient group were examined using the multiple linear regression model.

RESULTS

No group difference was found about volumetric measurement in any of the subcortical regions. Vertex-wise analysis revealed areas of significant shape atrophy in bilateral putamen and bilateral pallidum in the patients with CTN compared to healthy controls. Besides, the patient group exhibited shape expansion in the head of the right caudate nucleus compared to healthy subjects. In addition, shape deformation in the head of the right caudate nucleus was positively associated with VAS score in CTN.

CONCLUSION

The patients with CTN display shape alterations in the specific subregions of basal ganglia, which may contribute to the pathophysiology of this refractory disorder and may be useful for translational medicine.

Risk Factors for Unilateral Trigeminal Neuralgia Based on Machine Learning

Purpose

Neurovascular compression (NVC) is considered as the main factor leading to the classical trigeminal neuralgia (CTN), and a part of idiopathic TN (ITN) may be caused by NVC (ITN-nvc). This study aimed to explore the risk factors for unilateral CTN or ITN-nvc (UC-ITN), which have bilateral NVC, using machine learning (ML).

Methods

A total of 89 patients with UC-ITN were recruited prospectively. According to whether there was NVC on the unaffected side, patients with UC-ITN were divided into two groups. All patients underwent a magnetic resonance imaging (MRI) scan. The bilateral cisternal segment of the trigeminal nerve was manually delineated, which avoided the offending vessel (Ofv), and the features were extracted. Dimensionality reduction, feature selection, model construction, and model evaluation were performed step-by-step.

Results

Four textural features with greater weight were selected in patients with UC-ITN without NVC on the unaffected side. For UC-ITN patients with NVC on the unaffected side, six textural features with greater weight were selected. The textural features (rad_score) showed significant differences between the affected and unaffected sides (p < 0.05). The nomogram model had optimal diagnostic power, and the area under the curve (AUC) in the training and validation cohorts was 0.76 and 0.77, respectively. The Ofv and rad_score were the risk factors for UC-ITN according to nomogram.

Conclusion

Besides NVC, the texture features of trigeminal-nerve cisternal segment and Ofv were also the risk factors for UC-ITN. These findings provided a basis for further exploration of the microscopic etiology of UC-ITN.

MRI features of responsible contacts in vascular compressive trigeminal neuralgia and prediction modeling

BACKGROUND

Multiple neurovascular contacts in patients with vascular compressive trigeminal neuralgia often challenge the diagnosis of responsible contacts.

PURPOSE

To analyze the magnetic resonance imaging (MRI) features of responsible contacts and establish a predictive model to accurately pinpoint the responsible contacts.

MATERIAL AND METHODS

Sixty-seven patients with unilateral trigeminal neuralgia were enrolled. A total of 153 definite contacts (45 responsible, 108 non-responsible) were analyzed for their MRI characteristics, including neurovascular compression (NVC) grading, distance from pons to contact (D_pons-contact), vascular origin of compressing vessels, diameter of vessel (D_vessel) and trigeminal nerve (D_{trigeminal nerve}) at contact. The MRI characteristics of the responsible and non-responsible contacts were compared, and their diagnostic efficiencies were further evaluated using a receiver operating characteristic (ROC) curve. The significant MRI features were incorporated into the logistics regression analysis to build a predictive model for responsible contacts.

RESULTS

Compared with non-responsible contacts, NVC grading and arterial compression ratio (84.44%) were significantly higher, D_pons-contact was significantly lower at responsible contacts (P < 0.001, 0.002, and 0.033, respectively). NVC grading had a highest diagnostic area under the ROC curve (AUC) of 0.742, with a sensitivity of 64.44% and specificity of 75.00%. The logistic regression model showed a higher diagnostic efficiency, with an AUC of 0.808, sensitivity of 88.89%, and specificity of 62.04%.

CONCLUSION

Contact degree and position are important MRI features in identifying the responsible contacts of the trigeminal neuralgia. The logistic predictive model based on D_pons-contact, NVC grading, and vascular origin can qualitatively improve the prediction of responsible contacts for radiologists.

Endoscopic Vascular Decompression for the Treatment of Trigeminal Neuralgia: Clinical Outcomes and Technical Note

Purpose

Microvascular decompression (MVD) surgery is considered as an effective method with which to treat trigeminal neuralgia (TN). However, sometimes MVD surgery fails due to incomplete decompression of the responsible vessels caused by a poor visual field. In this study, we evaluated the benefits of endoscopic visualization and the value of full endoscopic vascular decompression (EVD) by describing the surgical results of 20 patients with TN after EVD.

Patients and Methods

This was a retrospective study in a single institution of 20 patients with TN who received EVD between April 2018 and October 2019. All patients underwent EVD via the suboccipital retrosigmoid approach without microscopy at any stage. Abnormal muscle response (AMR) and brainstem auditory evoked potentials (BAEPs) were routinely monitored throughout the procedure. Follow-up was conducted by outpatient and telephone interviews. The degree of facial pain was graded using the Barrow Neurological Institute (BNI) pain intensity score; a BNI of 1 was considered as the best result while a BNI of 2 or 3 was considered as a satisfactory result. Follow-up time ranged from 8 to 24 months, with a mean of 18±4.36 months.

Results

All 20 patients with severe preoperative pain (BNI of 5) achieved immediate relief or complete control of pain after surgery (BNI of 1 to 2). Vascular conflicts were observed during surgery in all of the patients. None of the patients experienced hearing loss, facial paralysis, intracranial infection, cerebrospinal fluid leakage, cerebral hemorrhage, or death, following the operation.

Conclusion

When carried out by surgeons with endoscopic experience, EVD can provide a clear surgical field of view and reduce the risk of surgical injury. Our findings indicate that EVD is a safe and effective surgical method for the treatment of TN.