Trigeminal neuralgia is caused by maxillary and mandibular nerve entrapment: Greater incidence of right-sided facial symptoms is due to the foramen rotundum and foramen ovale being narrower on the right side of the cranium

A Retrospective Analysis of Medical Management Strategies for Trigeminal Neuralgia: An Institutional Review

Background Neuropathic pain results from nervous system damage, and trigeminal neuralgia (TN), also called tic douloureux, is a chronic disorder affecting the trigeminal nerve. TN causes sudden, severe, recurring facial pain that can be highly disabling. Treatment usually involves medications like carbamazepine, oxcarbazepine, gabapentin, or baclofen to manage nerve pain. If medications are ineffective, surgical interventions like microvascular decompression or gamma knife radiosurgery may be explored for symptom relief. Aim and objectives This study aims to assess the demographic characteristics and clinical features of patients with TN treated at a private institution. The objective was to assess key demographic factors, including age, gender, and the affected trigeminal nerve divisions, with a focus on identifying the most frequently involved nerve divisions in TN cases. Methodology This five-year retrospective study (January 2019-April 2023) in the Oral Medicine and Radiology Department analyzed 483 TN cases, including 300 patients with confirmed primary TN and complete records. Dental Information Archive System (DIAS) data covered demographics, clinical features, treatments, and outcomes. Pain levels were assessed using the visual analog scale (VAS). LFTs monitor the long-term effects of medications like carbamazepine. Statistical analysis employed descriptive statistics, chi-square tests, and t-tests, with p < 0.05 considered significant. Results Of 7,500 outpatients in the Oral Medicine Department, 483 were diagnosed with TN, and 300 met the diagnostic criteria for inclusion in a five-year study (January 2019-April 2023). The average age was 60 years for men and 58.5 years for women. TN primarily affected the right side in 158 patients (56%), while the left side was involved in 114 (43%) of the cases (p = 0.04) and most commonly involved the maxillary nerve (V2) in 159 patients (53%) and the mandibular nerve (V3) in 141 patients (47%), with a slight female predominance (p = 0.02). One hundred thirty-five patients (45%) used carbamazepine alone, while 84 were treated with carbamazepine and gabapentin, and 81 were treated with carbamazepine and baclofen. The combination of carbamazepine and gabapentin was the most effective, achieving pain control in 123 patients (75%) compared to 94 patients (70%) with carbamazepine alone and 119 patients (72%) with carbamazepine and baclofen (p = 0.06). VAS scores showed better pain relief with carbamazepine and gabapentin (VAS: 3.8 ± 1.0), carbamazepine alone (mean VAS: 4.5 ± 1.2) and carbamazepine with baclofen (mean VAS: 4.2 ± 1.1). In long-term management, 45 patients (15%) discontinued due to side effects, while 105 patients (35%) continued on carbamazepine alone, 90 patients (30%) on carbamazepine with gabapentin, and 60 patients (20%) on carbamazepine with baclofen (p = 0.04). LFTs were performed on 240 patients (80%), while 60 patients (20%) did not undergo LFTs. Conclusions This study underscores the treatment of TN, with anticonvulsants as the primary therapy and alternative options available for refractory cases. However, limitations like small sample size and lack of long-term follow-up affect the findings' generalizability. The results highlight the importance of treatment plans and the potential advantages of combination therapies in clinical practice.

Surgical Removal of Foramen Ovale Osteophyte Completely Relieved Atypical Trigeminal Neuralgia: A Case Report and Literature Review

Atypical trigeminal neuralgia (TN), usually caused by nonvascular compression, lacks a clearly localized trigger and complete remission periods. Although variations of foramen ovale may compress the mandibular nerve branch of the trigeminal nerve, resulting in atypical TN, only a few case reports are reported in the literature. The authors describe a case of a 50-year-old female diagnosed with atypical TN for two months. A high-resolution computed tomography imaging revealed an osteophyte of the left foramen ovale that may compress the mandibular nerve branch of the trigeminal nerve. The patient underwent osteophyte resection, and the pain disappeared completely and immediately after surgery without recurrence in the follow-up to six months. The numbness was also relieved slightly. This case provides a new perspective on the clinical diagnosis and treatment of patients with atypical TN.

Systematic review on the frequency of occurrence in nerve branches and the side of the face involved in trigeminal neuralgia and its clinical implication

Purpose

The purpose of this systematic review is to answer the focused question, "What is the commonly affected nerve branch and the side of the face involved in trigeminal neuralgia?"

Types of studies reviewed

This systematic review included studies reporting commonly affected trigeminal nerve branches and the side of the face involved in trigeminal neuralgia. To find the potential studies published, the authors utilized specific search databases such as PubMed, and Google scholar.

Results

Among 132 published studies, the authors selected only 11 to be included for this systematic review. The sample size ranged from 50 to 43,518 study subjects. This review identified that the mandibular branches of the trigeminal nerve were the most affected, followed by the maxillary branch. The review also identified that the right side of the face was predominantly affected.

Conclusion and practical implications

The authors of this review identified a higher occurrence of trigeminal neuralgia in the mandibular division of the nerve, commonly affected on the right side of the face. Further prospective-based research and meta-analysis are required to validate the commonly occurring trigeminal nerve branch and sidedness of the face involved with its clinical implications in trigeminal neuralgia.

When the nerve keeps firing: an institutional experience and systematic review on delayed response after microvascular decompression for trigeminal neuralgia

BACKGROUND

This study aimed to investigate the occurrence of delayed response following microvascular decompression (MVD) in patients with trigeminal neuralgia (TN) and identify potential contributing factors. Additionally, we present two cases with delayed relief observed at our institution.

METHOD

Two TN patients with delayed response and clear intra-operative arterial findings are presented in this study. Furthermore, we conducted a systematic review by searching electronic bibliographic databases, including MEDLINE (PubMed), Web of Science, Scopus, and Embase, from inception to 2022.

RESULTS

We identified a total of 28 full-text articles involving 322 TN patients who experienced delayed pain relief. Out of these, only 11 studies provided sufficient evidence and were included in the final analysis. Among the patients, 73.46% were female. The mean incidence rate of delayed response after MVD treatment for TN was 10.5%, with a range of 0.95 to 57.14% across different studies. The mean age of these patients was 59.86 years. The reported time to pain relief in the existing reports was at least 4 days post-surgery. In 72.88% of the reported cases, right-side dominance was observed. The majority of delayed cases experienced pain relief within 3 months, with a median time of 1 month.

CONCLUSIONS

A thorough examination of the probability of delayed pain relief after MVD for TN and understanding the characteristics of this phenomenon can offer surgeons valuable post-operative guidance and aid in decision-making regarding potential immediate reoperation.

Association Between Foramen Rotundum and Trigeminal Neuralgia in the Saudi Population: A Radiological Study

The trigeminal nerve is responsible for transmitting sensory information from the face, nasal and mouth cavities, and most of the scalp. Trigeminal neuralgia (TN) is a chronic facial pain disorder characterized by spontaneous paroxysmal pain throughout the distribution of the trigeminal nerve. This study investigated the morphological and morphometric variations of the foramen rotundum (FR) and its association with TN through a retrospective radiological analysis. A cohort of 97 participants from King Fahad University Hospital, Saudi Arabia, comprising 57 TN patients and 40 controls, underwent head CT scans for measurement and analysis. The study revealed significant differences in the FR morphology between TN patients and controls, particularly noting narrower FR measurements among TN individuals, especially in females. The right side demonstrated narrower FR dimensions, potentially correlating with the predominant side of pain in TN patients. While the presence of bony spurs was absent in all participants, variations in FR shape, size, and spatial positioning were observed and compared across genders and groups. These findings provide crucial insights into the potential anatomical factors contributing to TN, emphasizing the importance of understanding FR variations in clinical assessment and management of TN cases. Further research focusing on FR morphology and its clinical implications is recommended to enhance understanding and aid medical professionals in addressing TN-related concerns.

Sex differences in trigeminal neuralgia: a focus on radiological and clinical characteristics

BACKGROUND

It is well established that trigeminal neuralgia is more prevalent in females than in males. Neurovascular compression with morphological changes of the trigeminal root represents the most recognized etiological factor. However, other factors may play a role in the framework of a multi-hit model. The primary aim of this study was to investigate sex differences in radiological and clinical characteristics of trigeminal neuralgia to better understand the multifactorial origin of this peculiar neuropathic pain condition.

METHODS

In this cross-sectional study patients with a definite diagnosis of primary trigeminal neuralgia were consecutively enrolled. Each patient underwent 3T MRI with sequences dedicated to the study of neurovascular compression. Major morphological changes of the trigeminal root were quantitatively assessed. Clinical characteristics were systematically collected through a dedicated questionnaire. A logistic regression model was implemented to predict radiological and clinical characteristics based on sex.

RESULTS

A total of 114 patients with classical (87) or idiopathic trigeminal neuralgia (27) were enrolled. Female sex was predictive for idiopathic trigeminal neuralgia. Male sex was predictive, among the comorbidities and clinical characteristics, for hypertension, the involvement of the left side and the second trigeminal division, alone or with the ophthalmic division.

DISCUSSION

The preponderance of TN in the female sex and the association between idiopathic TN and the female sex suggest the role of additional etiological factors in the framework of a multi-hit model. The identification of clinical variables predicted by sex suggests the possibility that distinct phenotypes, with peculiar pathophysiological and therapeutic aspects, may occur in females and males.

Association of concomitant continuous pain in trigeminal neuralgia with a narrow foramen ovale

Background

The pathogenesis of concomitant continuous pain remains unclear and is worthy of further study. In this clinical study, we aimed to explore the potential role of a narrow foramen ovale in the development of concomitant continuous pain.

Methods

A total of 108 patients with classical trigeminal neuralgia affecting the third branch of the trigeminal nerve and 46 healthy individuals were enrolled in this study. Three-dimensional reconstructed computerized tomography images of all participants were collected, and the morphometric features of the foramen ovale were examined by two investigators who were blinded to the clinical data of the patients.

Results

In this cohort, patients with concomitant continuous pain suffered from more sensory abnormalities (18.4% vs. 2.9%, p = 0.015) and responded more poorly to medication (74.3% vs. 91.9%, p = 0.018) than patients without concomitant continuous pain. While no significant differences regarding the mean length (5.02 mm vs. 5.36 mm, p > 0.05) and area (22.14 mm2 vs. 23.80 mm2, p > 0.05) were observed between patients with and without concomitant continuous pain, the mean width of the foramen ovale on the affected side in patients with concomitant continuous pain was significantly narrower than that in patients without concomitant continuous pain (2.01 mm vs. 2.48 mm, p = 0.003).

Conclusion

This neuroimaging and clinical study demonstrated that the development of concomitant continuous pain was caused by the compression of the trigeminal nerve owing to a narrow foramen ovale rather than responsible vessels in classical trigeminal neuralgia.

New insight into the mandibular nerve at the foramen ovale level for percutaneous radiofrequency thermocoagulation

Background

Percutaneous radiofrequency thermocoagulation (RFTC) has been widely utilized in the management of trigeminal neuralgia. Despite using image guidance, accurate needle positioning into the target area still remains a critical element for achieving a successful outcome. This study was performed to precisely clarify the anatomical information required to ensure that the electrode tip is placed on the sensory component of the mandibular nerve (MN) at the foramen ovale (FO) level.

Methods

The study used 50 hemi-half heads from 26 South Korean adult cadavers.

Results

The cross-sectioned anterior and posterior divisions of the MN at the FO level could be distinguished based on an irregular boundary and color difference. The anterior division was clearly brighter than the posterior one. The anterior division of the MN at the FO level was located at the whole anterior (38.0%), anteromedial (6.0%), anterior center (8.0%), and anterolateral (22.0%) parts. The posterior division was often located at the whole posterior or posterolateral parts of the MN at the FO level. The anterior divisions covered the whole MN except for the medial half of the posterolateral part in the overwrapped images of the cross-sectional areas of the MN at the FO level. The cross-sectional areas of the anterior divisions were similar in males and females, whereas those of the posterior divisions were significantly larger in males (P = 0.004).

Conclusions

The obtained anatomical information is expected to help physicians reduce unwanted side effects after percutaneous RFTC within the FO for the MN.

The tic douloureux of Alexis Pujol (1739-1804)

In 1787, Alexis Pujol (1739-1804) wrote the first monograph exclusively on trigeminal neuralgia which he called "tic douloureux", or painful tic. Although it was not a seminal description, his monograph was a valuable clinical summary that helped his contemporaries make an exact diagnosis, even though it did not offer proven treatments. Unlike most in his day, Pujol adhered to the theory of electricity, seeing it as the vector of information transmission by the nerve. This made him a precursor and put him in a position to propose a novel pathophysiological theory of pain, not yet qualified as neuralgic. His thinking illustrates that, at the dawn of the nineteenth century, a provincial physician working alone was able to make his contribution to building medical knowledge, particularly in the field of neurology. After a brief biography of Pujol, this article will cite from his book to show the relevance of his clinical observations, which are still valuable today. Without omitting the inspiration, he took from his predecessors, this article also mentions the work of those who followed in his footsteps.

Examining the Clinical Characteristics of Trigeminal Neuralgia at a Dental Hospital: A Prospective Study

Background and objective Trigeminal neuralgia (TN) is a paroxysmal shock-like neuropathic pain condition that causes sudden, typically unilateral, severe, brief, stabbing, and recurrent sensations in the distribution of one or more trigeminal nerve branches. Although the clinical profile of TN patients has been generally established, there has never been a study on the condition among the population of Northeast India. Furthermore, there is scarce research describing the clinical features of TN in patients who visit a dental college. In light of this, we conducted this study to assess the clinical characteristics and parameters of TN in an Indian population. Methods Medical records of 60 patients with TN were reviewed prospectively for patient demographics, characteristics of the pain, and treatment modalities. Results Of the 60 patients, 55% were male, and 45% were female. The peak incidence was found in the age range of 55-64 years. Pain occurred equally on the right and left sides of the face. The maxillary division of the trigeminal nerve was the most frequently affected (40%) region, followed by mandibular division (35%) and the combined maxillary and mandibular division alone (25%). Most patients described their attacks as shock-like (78.33%) and of spontaneous onset (86.67%). Conclusion In the present study, TN affected males more than females and occurred most frequently in patients aged 55-64 years. A comparative analysis of the pain characteristics between different age groups and genders is useful for the management of these patients.

Narrow ovale foramina may be involved in the development of primary trigeminal neuralgia

Background

The etiology of primary trigeminal neuralgia remains unclear and is worthy of further study; In this study, the morphometric characteristics of ovale foramina between various groups were compared and analyzed to explore the novel cause of primary trigeminal neuralgia.

Methods

High-resolution three-dimensional reconstruction images from head computed tomography of 109 patients with primary trigeminal neuralgia affecting the third branch of the trigeminal nerve and 46 healthy controls were retrospectively reviewed. Among the 109 primary trigeminal neuralgia patients, 79 patients with apparent neurovascular compression (not simply contact) demonstrated on MRI or during surgery were divided into the classical trigeminal neuralgia group and 30 patients with MRI showing no significant abnormalities were divided into idiopathic trigeminal neuralgia group. The morphometric parameters including the area, width and length of ovale foramina were examined through the use of radiologic methods.

Results

In this study, the average minimum area, width and length of 79 ovale foramina on the affected and unaffected sides in the classical trigeminal neuralgia group were 21.83 ± 8.45, 21.94 ± 7.93 mm², 2.32 ± 0.91, 2.58 ± 0.81, 5.32 ± 1.29, and 5.26 ± 1.21 mm, respectively. No significant difference in these parameters was observed (p > 0.05). However, in the idiopathic trigeminal neuralgia group, the average minimum area, width and length of 30 ovale foramina were 21.33 ± 8.21, 22.85 ± 8.36 mm², 2.25 ± 0.90, 2.79 ± 0.96, 5.20 ± 1.27, and 5.28 ± 1.19 mm, respectively. The width on the symptomatic side was significantly smaller (p = 0.03) than that on the asymptomatic side. No significant difference in area (p = 0.48) or length (p = 0.79) was observed. In addition, when compared with the healthy control group, the area and width of ovale foramina on the symptomatic side in both groups were significantly smaller. No significant difference in length was observed.

Conclusions

By comparing and analyzing the statistical data, it can be inferred that a narrow foramen ovale is associated with primary trigeminal neuralgia, as well as its recurrence after microvascular decompression.

Emerging roles of lncRNAs in the pathogenesis, diagnosis, and treatment of trigeminal neuralgia

Trigeminal neuralgia (TN) is one of the most common neuropathic pain disorders and is often combined with other comorbidities if managed inadequately. However, the present understanding of its pathogenesis at the molecular level remains lacking. Long noncoding RNAs (lncRNAs) play crucial roles in neuropathic pain, and many studies have reported that specific lncRNAs are related to TN. This review summarizes the current understanding of lncRNAs in the pathogenesis, diagnosis, and treatment of TN. Recent studies have shown that the lncRNAs uc.48+, Gm14461, MRAK009713 and NONRATT021972 are potential candidate loci for the diagnosis and treatment of TN. The current diagnostic system could be enhanced and improved by a workflow for selecting transcriptomic biomarkers and the development of lncRNA-based molecular diagnostic systems for TN. The discovery of lncRNAs potentially impacts drug selection for TN; however, the current supporting evidence is limited to preclinical studies. Additional studies are needed to further test the diagnostic and therapeutic value of lncRNAs in TN.

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

OBJECTIVES

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.

METHODS

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).

RESULTS

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).

CONCLUSIONS

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.

KEY POINTS

• 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.

Recurrent Trigeminal Neuralgia: A Case Series and a Review of the Literature

Trigeminal neuralgia is a peripheral neuropathy characterized by intermittent episodes of severe facial pain originating in the sensory nucleus of the trigeminal nerve. The most commonly involved area is the mandibular division with a higher prevalence on the right side. Advances in the field of MRI have played an important role in its diagnosis, especially in presurgical assessment, to probe into any secondary causes of nerve compression and/or neurovascular conflict. The condition is primarily managed medically, although many patients may require surgical or radiotherapeutic intervention. A recurrence rate ranging from 6 to 41% has been postulated. Reasons for recurrence are mainly attributed to improper operative techniques, dislocation of the Teflon implant, or granuloma formation. MRI serves as a powerful tool in the segmental evaluation of the trigeminal nerve. A proper diagnosis with a structured treatment protocol is critical for managing such cases of trigeminal neuralgia. In this report, we present a series of two cases of recurrent trigeminal neuralgia.

Evaluation of Anatomoradiological Findings on Trigeminal Neuralgia Patients Using Computed Tomography and Cone-Beam Computed Tomography

The study aimed to establish and evaluate anatomoradiological landmarks in trigeminal neuralgia patients using computed tomography (CT) and cone-beam CT. CT images of 40 trigeminal neuralgia (TN) and 40 healthy individuals were retrospectively analyzed and enrolled in the study. The width and length of the foramen rotundum (FR), foramen ovale (FO), foramen supraorbitale, and infraorbitale were measured. The distances between these foramen, between these foramen to the median plane, and between the superior orbital fissure, FO, and FR to clinoid processes were also measured bilaterally. Variations were evaluated according to groups. Significant differences were found for width and length of the foramen ovale, length of the foramen supraorbitale, and infraorbitale between TN and control subjects (p < 0.05). On both sides, FO gets narrower and the length of the infraorbital and supraorbital foramen shortens in the TN group. In most of the control patients, the plane which passes through the infraorbital and supraorbital foramen intersects with impression trigeminale; 70% on the right-side, and 67% in the left-side TN groups. This plane does not intersect with impression trigeminale and deviates in certain degrees. The determination of specific landmarks allows customization to individual patient anatomy and may help the surgeon achieve a more selective effect with a variety of percutaneous procedures in trigeminal neuralgia patients.

Evaluation of transcutaneous electrical nerve stimulation as an adjunct therapy in trigeminal neuralgia - a randomized double-blind placebo-controlled clinical study

BACKGROUND

Trigeminal neuralgia (TN) is a severe form of pain that affects the daily activities of a patient. Transcutaneous electrical nerve stimulation (TENS) therapy is an emerging option for the treatment of acute and chronic pain. The aim of this study was to evaluate the effect of TENS therapy as an adjunct to drug therapy for the treatment of TN.

METHODS

A total of 52 patients diagnosed with TN according to the International Classification of Headache Disorders (version 3) were included. Each patient was randomized to either the TENS or placebo TENS groups. Intervention was given in continuous mode and 100-Hz frequency for 20 mins biweekly for 6 weeks. Parameters were measured at baseline, TENS completion and 3 months, 6 months, and 1 year of follow up. The parameters observed were mean carbamazepine dose, mean visual analog scale (VAS) score, mean present pain intensity (PPI) score, and functional outcome. Non-parametric analyses, one-way ANOVA and the Kruskal-Wallis test were applied for intragroup comparisons, while the Mann-Whitney U test and independent t-test were used for intergroup comparisons of variables. The chi-square test was applied to analyze categorical data.

RESULTS

Compared to the placebo TENS group, the mean dose of carbamazepine in the TENS group was significantly reduced at TENS completion, as well as at 6 months and 1 year follow up. Changes in mean VAS score, mean PPI score, and functional outcome did not show significant differences between the groups (P>0.05).

CONCLUSION

TENS therapy does not lead to any changes in pain levels but it may reduce the mean dose of carbamazepine when used as an adjunct treatment in patients with TN.

A Prospective Study to Examine the Association of the Foramen Ovale Size with Intraluminal Pressure of Pear-Shaped Balloon in Percutaneous Balloon Compression for Trigeminal Neuralgia

INTRODUCTION

Percutaneous balloon compression (PBC) is an effective and safe option for patients with trigeminal neuralgia. A pear-shaped balloon can be used to identify the proper compression of the Gasserian ganglion during the PBC procedure. The aim of this study was to evaluate the relationship between the foramen ovale (FO) size and intraluminal pressure of the pear-shaped balloon.

METHODS

Thirteen patients that presented with classical trigeminal neuralgia were scheduled to undertake PBC surgery at the Pain Department of the Third Xiangya Hospital, Central South University, from November 2020 to April 2021. Three-dimensional computed tomography reconstruction of the skull base was performed to capture the feature of FO preoperatively. The intraluminal pressure was continuously recorded when a pear-shaped balloon was obtained during the procedure. Correlation analysis was calculated to determine the association of the intraluminal balloon pressure with FO parameter.

RESULTS

All participants reported complete relief of pain at discharge. The enduring analgesic effect of PBC was maintained in all patients with a median follow-up up to 5.5 months (range, 3-8 months). The average intraluminal balloon pressure was 161.5 ± 29.4 kPa at the initial compression (P1), and 134.8 ± 21.5 kPa at the ending of compression (P2), respectively. P1 was significantly correlated with the length (r = 0.61, P = 0.024) of FO. Similarly, a significant and positive correlation was observed between P2 and the length (r = 0.63, P = 0.022) of FO.

CONCLUSIONS

Preoperative assessment of FO may be a potential predictor of intraluminal pressure to reach a pear-shaped balloon during PBC treatment. Narrow FO is associated lower intraluminal balloon pressure.

Clinical characteristics of trigeminal neuralgia in a dental hospital

Background

Neurovascular compression (NVC) is a well-known cause of trigeminal neuralgia (TN). However, patients with idiopathic TN (ITN) do not have evidence of NVC on magnetic resonance imaging (MRI), and other patients may remain asymptomatic despite evidence of NVC on MRI. This suggests that there may be additional risk factors for TN development other than NVC. Although epidemiological factors, such as age and sex differences, are useful for understanding the pathophysiology of TN, detailed statistics for each TN subtype are currently unavailable. Therefore, this study aimed to classify patients with TN into the following groups based on data extracted from past medical records: classical TN (CTN), secondary TN, and ITN.

Methods

The characteristics of the groups and their differences were explored.

Results

CTN was more common in women than in men, as previously reported, whereas ITN was more common in men than in women. The ratio of pain sites located on the right side of the face was high in all groups. Patients with CTN were also prone to NVC on the asymptomatic side.

Conclusion

By investigating TN subtype, it may be possible to elucidate the pathophysiology of TN. This would greatly improve treatment outcomes.

Occipital Neuralgia and Its Management: An Overview

Background

Greater and lesser occipital neuralgias are primary neuralgias that are relatively uncommon, where the pain is felt in the distribution of these nerves.

Objective

This review paper was intended to describe the features and management of occipital neuralgia in the context of a challenging case.

Material and Methods

We looked at succinct literature from the past 30 years. We compared the features of our challenging case given in the current literature. In addition, an overview of the current literature is provided.

Results

The case, although proved to be a diagnostic challenge, we were able to reach a conclusion and render the patient almost complete pain relief by conservative management modalities. It proved to be a rare presentation of occipital neuralgia with unusual pain distribution, and we are able to describe a literature-based explanation for this entity to be a diagnostic and management challenge.

Conclusion

Primary headaches, i'n general, are a group of headache disorders that require exquisite diagnostic skills. The clinical history is a key factor when making an accurate diagnosis, and to establish an appropriate management plan.

MRI Texture Analysis Reveals Brain Abnormalities in Medically Refractory Trigeminal Neuralgia

Background: Several neuroimaging studies report structural alterations of the trigeminal nerve in trigeminal neuralgia (TN). Less attention has been paid to structural brain changes occurring in TN, even though such changes can influence the development and response to treatment of other headache and chronic pain conditions. The purpose of this study was to apply a novel neuroimaging technique-texture analysis-to identify structural brain differences between classical TN patients and healthy subjects. Methods: We prospectively recruited 14 medically refractory classical TN patients and 20 healthy subjects. 3-Tesla T1-weighted brain MRI scans were acquired in all participants. Three texture features (autocorrelation, contrast, energy) were calculated within four a priori brain regions of interest (anterior cingulate, insula, thalamus, brainstem). Voxel-wise analysis was used to identify clusters of texture difference between TN patients and healthy subjects within regions of interest (p < 0.001, cluster size >20 voxels). Median raw texture values within clusters were also compared between groups, and further used to differentiate TN patients from healthy subjects (receiver-operator characteristic curve analysis). Median raw texture values were correlated with pain severity (visual analog scale, 1-100) and illness duration. Results: Several clusters of texture difference were observed between TN patients and healthy subjects: right-sided TN patients showed reduced autocorrelation in the left brainstem, increased contrast in the left brainstem and right anterior insula, and reduced energy in right and left anterior cingulate, right midbrain, and left brainstem. Within-cluster median raw texture values also differed between TN patients and healthy subjects: TN patients could be segregated from healthy subjects using brainstem autocorrelation (p = 0.0040, AUC = 0.84, sensitivity = 89%, specificity = 70%), anterior insula contrast (p = 0.0002, AUC = 0.92, sensitivity = 78%, specificity = 100%), and anterior cingulate energy (p = 0.0004, AUC = 0.92, sensitivity = 78%, specificity = 100%). Additionally, anterior insula contrast and duration of TN were inversely correlated (p = 0.030, Spearman r = -0.73). Conclusions: Texture analysis reveals distinct brain abnormalities in TN, which relate to clinical features such as duration of illness. These findings further implicate structural brain changes in the development and maintenance of TN.

Trigeminal Neuralgia: Basic and Clinical Aspects

The trigeminal nerve is the largest of all cranial nerves. It has three branches that provide the main sensory innervation of the anterior two-thirds of the head and face. Trigeminal neuralgia (TN) is characterized by sudden, severe, brief, and stabbing recurrent episodes of facial pain in one or more branches of the trigeminal nerve. Pain attacks can occur spontaneously or can be triggered by non-noxious stimuli, such as talking, eating, washing the face, brushing teeth, shaving, a light touch or even a cool breeze. In addition to pain attacks, a proportion of the patients also experience persistent background pain, which along with autonomic signs and prolonged disease duration, represent predictors of worse treatment outcomes. It is now widely accepted that the presence of a neurovascular compression at the trigeminal root entry zone is an anatomic abnormality with a high correlation with classical TN. However, TN may be related to other etiologies, thus presenting different and/or additional features. Since the 1960s, the anticonvulsant carbamazepine is the drug of choice for TN treatment. Although anti-epileptic drugs are commonly used to treat neuropathic pain in general, the efficacy of carbamazepine has been largely limited to TN. Carbamazepine, however, is associated with dose-limiting side-effects, particularly with prolonged usage. Thus, a better understanding and new treatment options are urgently warranted for this rare, but excruciating disease.

Prevalence of trigeminal neuralgia in Indian population visiting a higher dental care center in North India

Objectives:

The present study aims to determine the incidence and prevalence of trigeminal neuralgia (TN) in study population and difference in prevalence of TN in urban and rural population.

Materials and Methods:

This retrospective study includes 1215 study participants with typical idiopathic TN. Data regarding the age of onset, gender, site of involvement, and clinical presentations were retrieved from clinical records of patients reported from January 2011 to January 2018.

Results:

The study population consists of 1215 study participants aged between 21 and 87 years, with a mean age of 50.62 ± 15.872 years. The mandibular nerve is involved in most of the cases (56.9%), followed by maxillary nerve (42%). The right side of the face (57.1%) is more involved than the left side (38.8%). TN was more prevalent (52.4%) in rural population than urban population (47.6%).

Conclusion:

TN is more common in females than males, the right side of the face is more involved than the left side, and it is more commonly found in rural population than urban population.

Cone Beam Computed Tomographic Evaluation of Intracranial Physiologic Calcifications

OBJECTIVE

The aim of the present study was to evaluate the incidence of physiologic intracranial calcifications detected in cone beam computed tomography (CBCT) images of a Turkish subpopulation.

METHODS

The CBCT image of the full head of 573 patients taken between 2015 and 2018 was evaluated retrospectively. The prevalence of habenular calcification, petroclinoid ligament, coroid plexus, interclinoid ligament (ICL), and carotico-clinoid ligament (CCL) calcifications was investigated. The age and gender of the patients were recorded.

RESULTS

Intracranial calcification was found in 190 (33.1%) of 573 cases. The frequency of physiological calcifications is respectively; 19.2% were found as habenular, 4.88% as ICL, 3.83% as CCL, 2.7% as petroclinoid ligament, and 2.4% as choroid plexus. 38.2% of the women and 29.3% of the men had intracranial calcification. In 4 patients, both ICL and CCL ossification were detected. No statistically significant relationship was found between age, gender, and calcifications.

CONCLUSION

Cone beam computed tomography is a widely used imaging technique for dental diagnosis and treatment. Intracranial physiological calcifications may be a common incidental finding of CBCT scans.

Migraine Pain Location and Measures of Healthcare Use and Distress: An Observational Study

Introduction

Lateralized pain is a core diagnostic feature of migraine. In previous research, left-sided spinal pain was more frequent and associated with greater emotional distress and healthcare use than right-sided pain. We hypothesized therefore that patients with left-sided head pain might experience higher levels of distress or healthcare use than those with right-sided or bilateral pain.

Methods

Medical record information was extracted for 477 randomly selected patients with migraine seen in 2011 in a tertiary headache clinic. This included demographic data, pain location, handedness, comorbid psychiatric diagnoses, medical and emergency department visits, and use of selected headache medications.

Results and Discussion

Two hundred twenty-eight of four hundred seventy-seven (47.8%) patients reported lateralized pain, of which 107 (47.9%) patients were right sided compared with 65 (28.5%) left-sided patients (p=0.001), while 56 (24.5%) reported unilateral pain with no side predominance. Contrary to expectations, with the exception of self-reported posttraumatic stress disorder, there were no statistically significant differences between left and right in measures of psychiatric distress, emergency department visits, or healthcare use.

Conclusion

Although unilateral pain location can be helpful in making a migraine diagnosis, it does not appear to have additional clinical implications. Additionally, its absence does not rule out a diagnosis of migraine since more than half of migraineurs have bilateral head pain.

Cranial Nerve Foramina Part I: A Review of the Anatomy and Pathology of Cranial Nerve Foramina of the Anterior and Middle Fossa

Cranial nerve foramina are integral exits from the confines of the skull. Despite their significance in cranial nerve pathologies, there has been no comprehensive anatomical review of these structures. Owing to the extensive nature of this topic, Part I of our review, presented here, focuses on the foramina of the anterior and middle cranial fossae, discussing each foramen's shape, orientation, size, surrounding structures, and structures that traverse them. Furthermore, by comparing the size of each foramen against the cross-sectional areas of its contents, we estimate the amount of free space in each. We also review lesions that can obstruct the foramina and discuss their clinical consequences.

Modified Decompression of the Infraorbital Canal to Treat Trigeminal Neuralgia Affecting the Maxillary Branch

PURPOSE

To modify the method of treating trigeminal neuralgia (TN) affecting the maxillary branch and to provide clinical evidence of an etiologic hypothesis of narrowing bone canal compression.

MATERIALS AND METHODS

Forty patients who met the inclusion and exclusion criteria were included, and those with bony compression of the affected infraorbital canal (IOC) were selected by preoperative computer measurement. Modified decompression of the IOC was performed through the maxillary sinus with the assistance of a piezoelectric device and an endoscope. The results of the operation were evaluated.

RESULTS

Fourteen patients (35.00%) had bony compression of the affected IOC. During a mean follow-up period of 29.4 months, 11 patients (78.57%) had complete pain relief (excellent); 1 (7.14%) had moderate relief with carbamazepine administration. The success rate was 85.71% (12 of 14). The postoperative numbness rate was 35.71% (5 of 14).

CONCLUSION

Narrowing of the IOC might be a reason some patients with TN have no intracranial neurovascular compression and have pain localized to the distribution of the maxillary branch. Modified decompression of the IOC through the maxillary sinus is a safe, highly effective, and minimally invasive method to treat these patients.

Trigeminal neuralgia: a retrospective multicentre study of 320 Asian patients

OBJECTIVES

This study was performed to obtain the clinicodemographic data regarding patients with trigeminal neuralgia (TN) treated at oral-maxillofacial medicine clinics, as there is a paucity of such information in the Asian setting.

STUDY DESIGN

Retrospective multicenter study involving clinicodemographic information of 320 patients with TN diagnosed between 2001 and 2012 at eight regional oral-maxillofacial medicine clinics and followed up for at least 6 months. Statistical tests were performed to assess the associations among the clinicodemographic factors.

RESULTS

TN was mostly diagnosed during the seventh and sixth decades of life, with a median of 58.2 years (interquartile range = 13.0). Females were more commonly affected (61.6%). TN affected the right side more frequently, and the mandibular branch was most commonly involved (58.5%). Carbamazepine was the first-line drug of choice (87.5%).

CONCLUSIONS

Asian patients with TN exhibited features similar to those in Caucasian patients except for the increased affliction of the mandibular division.

Early response to medical treatment of trigeminal neuralgia in a Nigerian population

BACKGROUND

This study evaluates the clinical profile of patients suffering from trigeminal neuralgia (TN) and correlates the findings with early response of the patients to medical treatment.

PATIENTS AND METHODS

A 4-year prospective study in which patients diagnosed of TN were treated medically and followed up weekly for 8 weeks to determine early treatment outcome, in the University of Benin Teaching Hospital, Benin City, Nigeria.

RESULTS

Of the 287 patients seen during the study period, a total of 14 (4.9%) patients were diagnosed of TN. Thirteen (4.5%) of the cases were selected based on compliance to the 8-week follow-up visits, consisting of 8 (61.5%) males and 5 (38.5%) females, giving a ratio of 1.6:1. The mean age of the patients was 50±1.5 years. The mandibular (n = 6, 46.2%) and maxillary (n = 5, 38.5%) divisions of the trigeminal nerve were mostly affected. The lesion was slightly more common on the right side of the face (n = 7, 53.8%) than the left side (n = 6, 46.2%). Talking (n=4, 30.8%) and chewing (n = 3, 23.1%) were the most frequent trigger factors. The patients mostly described the pain as severe, spontaneous, and sharp (n = 5, 38.2%). Most patients became stable on tablets carbamazepine 200 mg 12 hourly, folic acid 5 mg daily, and phenytoin 100 mg daily. Good response was observed in most patients within 2 weeks (n = 6, 46.2%) of medical treatment, especially in patients at the seventh decade of age (n = 3, 23.1%) and those with lesions involving the mandibular division of the trigeminal nerve (n = 3, 23.1%).

CONCLUSION

This study shows early response of TN to medical treatment. We recommend combination therapy of carbamazepine and folic acid in the treatment of patients, especially elderly patients with lesions involving the mandibular division of the trigeminal nerve.

Sensory disturbances of buccal and lingual nerve by muscle compression: A case report and review of the literature

Introduction

Several studies on cadavers dissection have shown that collateral branches of the trigeminal nerve cross muscle bundles on their way, being a possible etiological factor of some nerve disturbances.

Case Report

A 45-year-old man attended to the Temporomandibular Joint and Orofacial Pain Unit of the Master of Oral Surgery and Implantology in Hospital Odontològic of Barcelona University, referring tingling in the left hemifacial región and ipsilateral lingual side for one year, with discomfort when shaving or skin compression.

Discussion

Several branches of the trigeminal nerve follow a path through the masticatory muscles, being the lingual nerve and buccal nerve the most involved. The hyperactivity of the muscle bundles that are crossed by nerve structures generates a compression that could explain certain orofacial neuropathies (numbness and / or pain) in which a clear etiologic factor can not be identified.

Key words:Buccal nerve, paresthesia, idiopathic trigeminal sensory neuropathy.

A retrospective study of 72 cases diagnosed with idiopathic trigeminal neuralgia in indian populace

Context: Trigeminal neuralgia is as a chronic, debilitating condition, which can have a major impact on quality of life. There are few reports of trigeminal neuralgia in oriental populations. Objectives: To evaluate the retrospective data of the patients diagnosed with idiopathic trigeminal neuralgia and to understanding the disorder in the Indian populace. Methods: The retrospective data of 72 patients with typical idiopathic trigeminal neuralgia regarding age of onset, gender, site of involvement, clinical presentations and treatment received during three years of the follow up was collected and analyzed. Results: In the present retrospective study, the mean age was 54.9 years; female to male ratio was 2.13:1; rural to urban ratio 1.76:1 with 62.5% suffered trigeminal neuralgic pain on the right side. Carbamazepine was found to be highly effective in 60.8% of the cases on long-term basis with maintenance doses. Other treatment modalities were employed in more refractory cases including add-on of gabapentin, which relieved the symptoms for an additional duration of 13±3months. The neurolytic alcohol bloc was given in 30% of patients who stopped responding to combination of carbamazepine and gabapentin and relieved pain for a mean duration of 17.25±2.95 months. Twenty three percent of the patients (23%) required peripheral neurectomy. Conclusions: Carbamazepine was found to be highly effective in trigeminal neuralgia. Other treatment modality includes add-on of gabapentin, neurolytic alcohol blocs and peripheral surgical intervention in more refractory cases. Only limited cases needed further neurological consideration.

Key words:Trigeminal neuralgia, carbamazepine, gabapentin, alcohol bloc, peripheral neurectomy.

Functional and sensory evaluation of patients with idiopathic trigeminal neuralgia: comparison with controls

BACKGROUND

Idiopathic trigeminal neuralgia (ITN) can be associated with orofacial and sensory comorbidities.

OBJECTIVE

To evaluate the masticatory functional and sensory characteristics of patients with ITN compared with controls.

METHODS

We enrolled 119 patients and 30 healthy controls. They were evaluated with a systematic protocol: clinical orofacial evaluation questionnaire; a systematic approach of the mandibular function and the investigation of musculoskeletal comorbidities by the research diagnostic criteria for temporomandibular disorders (RDC/TMD) and the Helkimo indexes; and quantitative sensory testing (corneal reflex and gustative, olfactory, thermal, mechanical and pain thresholds).

RESULTS

The study group had more loss of vertical dimension than the controls (p=0.011) and restriction of the maximum mouth opening (p=0.024); they had more pain on mandibular movements (p=0.001), limitation of mandibular function (p<0.001), masticatory discomfort (p<0.001) and myofascial pain (p=0.001). Occlusion Helkimo index was lower in controls than patients. The study group had high tactile (p=0.025), warm (p=0.020) and cold (p=0.003) thresholds.

CONCLUSION

ITN may cause severe mandibular limitations that can be associated with the pain episodes and with sensory abnormalities. These findings indicate the affection of small and large nerve fibers and support the neuropathic nature of ITN. Sensory alterations can be part of the natural history of ITN and can be associated with the previous treatments including medication. They cause a high impact in quality of life.

Transcranial segment of the trigeminal nerve: macro-/microscopic anatomical study using sheet plastination

BACKGROUND

Trigeminal neuralgia (TN) may be caused by the mechanical compression of the trigeminal nerve. In the studies on the location of mechanical irritation and entrapment of the nerve, attention has been paid mostly to vascular structures in the subarachnoid space. Few studies have explored the relationship between the trigeminal nerve and its surrounding structures along its course in the skull base. The aim of this study was to examine and trace the root, ganglion and three divisions of the trigeminal nerve and their relationships with surrounding soft and bony structures in the skull base, and to identify the likely mechanical compression points.

METHODS

A total of 26 adult cadavers (ten females, 16 males; age range, 45-81 years) were examined in this study, eight for dissection and 16 for sheet plastination study.

RESULTS

Anatomical structures that may make the trigeminal nerve susceptible to entrapment in the skull base were located at (1) the inferolateral edge of the mouth of Meckel's cave, (2) the middle cranial fossa dura and the lateral wall of the anterior intracavernous portion of the internal carotid artery, (3) the ridge of the medial wall of the foramen rotundum, and (4) the twisted periosteum and venous plexus of the foramen ovale.

CONCLUSION

This study identified four likely mechanical compression points along the course of the trigeminal nerve in the skull base. Knowledge of these TN-susceptible sites may be useful to both skull base surgeon and TN-animal model researcher, particularly when they study TN without vascular compression.

Trigeminal neuralgia: frequency of occurrence in different nerve branches

Background:

Trigeminal neuralgia (TN) is neuropathic pain which can involve any part or side of the face.

Objectives:

The objectives of this study were to find the most common branch of trigeminal nerve affected and the most common side involved.

Patients and Methods:

This Cross sectional study was carried out on 100 patients of trigeminal neuralgia in one year time. The diagnosis was based on a detailed history, clinical examination and control of pain by carbamazepine being taken supplemented by radiographic investigations. The collected data was analysed by SPSS 16.

Results:

The age of the patients varied from 40 to 80 years with a mean age 54 years at the time of presentation. The males to females ratio was 1:2. The right side of the face was found to be involved in seventy patients (64 %) and left side in (36 %). No case presented with bilateral involvement. The Mandibular division was most commonly involved in this study (n = 55; 55%) and least was ophthalmic divisions (n = 6; 6%).

Conclusions:

This study demonstrated numerous clinical similarities of trigeminal neuralgia afflicting different populations. Right side was more involved along with mandibular division the most commonly affected. However studies needs to be done to know the exact reasons of involvement of the affected side and branches.

Trigeminal neuralgia: a retrospective study of 188 Thai cases

OBJECTIVE

To describe the clinical characteristics and treatment of trigeminal neuralgia (TN) in a group of Thai patients.

MATERIALS AND METHODS

Records of 188 patients with TN were reviewed retrospectively for patient demographics, the characteristics of the pain and treatment modalities.

RESULTS

Of the 188 patients, 37.2% were men and 62.8% were women. The peak incidence (46.8%) was in the age range of 50-69 years. Pain occurred on the right side of the face more often than on the left (1.8:1). The mandibular division of the trigeminal nerve was the most frequently affected (30.3%), followed by the combined maxillary and mandibular divisions (29.3%) and the maxillary division alone (25%). The majority described their attack as a sharp pain (77.6%), and the most common primary locations were at previous extraction sites (40.5%). The most common triggers were chewing (61.2%) and speaking (47.3%). Carbamazepine was the most common prescribed drug (76.1%) for the initial treatment. Combination drug therapy was introduced when the monotherapy failed to control the pain. Surgical intervention was the alternative choice of treatment in refractory cases.

CONCLUSION

TN affected women more than men, and this disorder occurred most frequently in patients aged 50 years and older. The mandibular division of the trigeminal nerve was most commonly involved.

[Bilateral trigeminal neuralgia: case report]

BACKGROUND AND OBJECTIVES

Trigeminal neuralgia is an extremely painful condition characterized by recurrent episodes of sudden, lancinating, shock-like pain lasting from a few seconds to two minutes usually unilateral. It has an annual incidence of approximately 4.3 in 100,000 in the general population and only 3% of those cases present bilateral manifestation. The objective of this report was to describe a rare case of bilateral trigeminal neuralgia.

CASE REPORT

A 61 years old housewife from Maranhão, Brazil, married, with a history of hypertension, presented with a six-year history of severe pain in the left V2-V3 regions, lasting 5 to 10 seconds, in the lateral aspect of the nose and mandible, worsening by talking, chewing, and with a decrease in temperature. She had been treated with chlorpromazine (3 mg every eight hours) and carbamazepine (200 mg every eight hours) during six months without improvement. On physical exam, the patient presented thermal and mechanical allodynia in the V2-V3 regions. She was using gabapentin (1,200 mg/day) with partial relief of the pain. The dose of gabapentin was increased to 1,500 mg/day and amitriptyline 12.5 mg at night was added to the therapeutic regimen. The patient evolved with mild and sporadical pain and a reduction in pain severity during 10 months; the dose of gabapentin was progressively reduced to 600 mg/day, and amitriptyline was maintained at 12.5 mg/day. After one year, the patient developed similar pain in the region of the right mandible, which improved with an increase in the dose of gabapentin to 900 mg/day. Head CT and MRI did not show any abnormalities.

CONCLUSIONS

Carbamazepine is the first choice for the treatment of trigeminal neuralgia; however, the use of gabapentin as the first pharmacological choice or in cases refractory to conventional therapy has been increasing.

Neuropathic orofacial pain: proposed mechanisms, diagnosis, and treatment considerations

The most common reason patients seek medical or dental care in the United States is due to pain or dysfunction. The orofacial region is plagued by a number of acute, chronic, and recurrent painful maladies. Pain involving the teeth and the periodontium is the most common presenting concern in dental practice. Non-odontogenic pain conditions also occur frequently. Recent scientific investigation has provided and explosion of knowledge regarding pain mechanisms and pathways and an enhanced understanding of the complexities of the many ramifications of the total pain experience. Therefore, it is mandatory for the dental professional to develop the necessary clinical and scientific expertise on which he/she may base diagnostic and management approaches. Optimum management can be achieved only by determining an accurate and complete diagnosis and identifying all of the factors associated with the underlying pathosis on a case-specific basis. A thorough understanding of the epidemiologic and etiologic aspects of dental. musculoskeletal, neurovascular, and neuropathic orofacial pain conditions is essential to the practice of evidence-based dentistry/medicine.