Chronic Facial Pain: Trigeminal Neuralgia, Persistent Idiopathic Facial Pain, and Myofascial Pain Syndrome-An Evidence-Based Narrative Review and Etiological Hypothesis

The outcomes of microvascular decompression for primary trigeminal neuralgia: insights from a single-center experience and technical advancements

Background

Microvascular decompression (MVD) remains the primary surgical treatment for trigeminal neuralgia due to its positive postoperative results. This study aims to evaluate the outcomes of patients with primary trigeminal neuralgia who underwent MVD. Additionally, the paper offers a detailed explanation of the surgical methodology of MVD employed at the neurosurgical hospital in Kazakhstan.

Methods

The study involved 165 medical records of patients with trigeminal neuralgia who underwent MVD between 2018 and 2020. Out of these 165 patients, 90 (54.55%) were included in the final analysis and were further evaluated using the Barrow Neurological Institute pain intensity score. Various variables were analyzed, including age, sex, affected side, dermatomes, offending vessel, and surgical intervention type. Moreover, the surgical technique employed at the hospital was described.

Results

The average follow-up period after the MVD procedure was 32.78 ± 9.91 months. The results indicated that out of the 90 patients, 80 (88.89%) achieved a good outcome as evidenced by BNI scores I and II. It was observed that patients with affected maxillary dermatomas and those with affected ophthalmic + maxillary dermatomas were more likely to experience fair + poor postsurgery BNI scores. On the other hand, patients with neurovascular conflicts involving the maxillary + mandibular dermatomas demonstrated good BNI scores (p = 0.01).

Conclusions

The outcomes of MVD in patients with primary trigeminal neuralgia showed good BNI scores within this study population. The outcome depended on the affected dermatome of the trigeminal nerve with the vessel. Additionally, patient positioning, intraoperative management including small skin incisions, minimal craniotomy, and precise closure of the dura, as well as intraoperative neurolysis, may contribute to achieving good clinical and satisfactory post-surgery aesthetic outcomes.

Pharmacological and Non-pharmacological Approaches for the Management of Neuropathic Pain in Multiple Sclerosis

Multiple sclerosis is a chronic inflammatory disease that affects the central nervous system and can cause various types of pain including ongoing extremity pain, Lhermitte's phenomenon, trigeminal neuralgia, and mixed pain. Neuropathic pain is a major concern for individuals with multiple sclerosis as it is directly linked to myelin damage in the central nervous system and the management of neuropathic pain in multiple sclerosis is challenging as the options available have limited efficacy and can cause unpleasant side effects. The literature search was conducted across two databases, PubMed, and Google Scholar. Eligible studies included clinical trials, observational studies, meta-analyses, systematic reviews, and narrative reviews. The objective of this article is to provide an overview of literature on pharmacological and non-pharmacological strategies employed in the management of neuropathic pain in multiple sclerosis. Pharmacological options include cannabinoids, muscle relaxants (tizanidine, baclofen, dantrolene), anticonvulsants (benzodiazepines, gabapentin, phenytoin, carbamazepine, lamotrigine), antidepressants (duloxetine, venlafaxine, tricyclic antidepressants), opioids (naltrexone), and botulinum toxin variants, which have evidence from various clinical trials. Non-pharmacological approaches for trigeminal neuralgia may include neurosurgical methods. Non-invasive methods, physical therapy, and psychotherapy (cognitive behavioral therapy, acceptance and commitment therapy and mindfulness-based stress reduction) may be recommended for patients with neuropathic pain in multiple sclerosis. The choice of treatment depends on the severity and type of pain as well as other factors, such as patient preferences and comorbidities. There is a pressing need for healthcare professionals and researchers to prioritize the development of better strategies for managing multiple sclerosis-induced neuropathic pain.

Risk factors associated with trigeminocardiac reflex in patients with trigeminal neuralgia during percutaneous balloon compression: A retrospective cohort study

BACKGROUND

The trigeminocardiac reflex (TCR) is a brainstem reflex commonly elicited during percutaneous balloon compression (PBC) for the treatment of trigeminal neuralgia (TN), which is characterized by drastic hemodynamic disturbances, such as bradycardia, arrhythmias and even cardiac arrest. In order to prevent catastrophic consequences, it is vital to screen the risk factors of TCR during perioperative period. The primary purpose of this study was to identify potential risk factors associated with TCR in patients with TN undergoing PBC, and to summarize the enlightenment of clinical anesthesia management.

METHODS

The clinical data of 165 patients diagnosed with TN undergoing PBC from January 2021 to December 2021 were retrospectively analyzed. TCR was defined as a sudden decrease in heart rate of 20% or more compared with baseline, and / or cardiac arrest, coinciding with the stimulus of any branch of the trigeminal nerve. And a clear cause-effect relationship between heart rate reduction and PBC-related intervention was required. All demographic characteristics as well as surgical and anesthetic data were compared between TCR group and TCR-free group. Univariate and multivariate logistic regression analysis were used to further analyze TCR-related risk factors.

RESULTS

Of the 165 patients enrolled in this study, 73 (44.2%) were male and 92 (55.8%) were female, and the average age was 64.22 ± 9.72 years. The incidence of TCR in the patients with TN during PBC was 54.5%. The results of multivariate regression analysis indicated that the risk factor for TCR was heart rate < 60 beats/min immediately before foramen ovale puncture (OR: 4.622; 95%CI: 1.470-14.531; P < 0.05).

CONCLUSION

Heart rate < 60 beats/min immediately before foramen ovale puncture was independently associated with TCR. Therefore, it is necessary for anesthesiologists to raise heart rate appropriately to prevent TCR during PBC.

Predictive value of foramen ovale size on pain recurrence after percutaneous balloon compression

OBJECTIVES

Primary trigeminal neuralgia (PTN) is a common cranial nerve disease in neurosurgery, which seriously endangers the physical and mental health of patients. Percutaneous balloon compression (PBC) has become an effective procedure for the treatment of PTN by blocking pain conduction through minimally invasive puncture. However, the recurrence of facial pain after PBC is still a major problem for PTN patients. Intraoperative balloon shape, pressure and compression time can affect the prognosis of patients with PBC after surgery. The foramen ovale size has an effect on the balloon pressure in Meckel's lumen. This study aims to analyse the predictive value of foramen ovale size for postoperative pain recurrence of PBC by exploring the relationship between foramen ovale size and postoperative pain recurrence of PBC.

METHODS

A retrospectively analysis was conducted on the clinical data of 60 patients with PTN who were treated with PBC in Department of Neurosurgery, Affiliated Hospital of Chengde Medical College from November 2018 to December 2021. We followed-up and recorded the Barrow Neurological Institute (BNI) pain score at 1, 3, 6 and 12 months after operation. According to the BNI pain score at 12 months after surgery, the patients were divided into a cure group (BNI pain score I to Ⅱ) and a recurrence group (BNI pain score Ⅲ to Ⅴ). The long diameter, transverse diameter and area of foramen ovale on the affected side and the healthy side of the 2 groups were measured. Receiver operating characteristic (ROC) curve and area under the curve (AUC) were used for analysis the relationship between the recurrence of pain and the long diameter, transverse diameter, area of foramen ovale on the affected side, and aspect ratio, transverse diameter ratio, area ratio of foramen ovale on the affected side to healthy side in the 2 groups.

RESULTS

At the end of 12 months of follow-up, 50 (83.3%) patients had pain relief (the cured group), 10 (16.7%) patients had different degrees of pain recurrence (the recurrence group), and the total effective rate was 83.3%. There were no significant differences in preoperative baseline data between the 2 groups (all P>0.05). The long diameter of foramen ovale on the affected side, the long diameter ratio and area ratio of foramen ovale on the affected/healthy side in the cured group were significantly higher than those in the recurrence group (all P<0.05), and there were no significant differences in the transverse diameter and area of foramen ovale on the affected side and the transverse diameter ratio of foramen ovale on the affected/healthy side between the 2 groups (all P>0.05). The ROC curve analysis showed that the AUC of the long diameter of foramen ovale on the affected side was 0.290 (95% CI 0.131 to 0.449, P=0.073), and the AUC of aspect ratio of foramen ovale on the affected side to healthy side was 0.792 (95% CI 0.628 to 0.956, P=0.004). The AUC of area ratio of foramen ovale on the affected side to healthy side was 0.766 (95% CI 0.591 to 0.941, P=0.008), indicating that aspect ratio and area ratio of foramen ovale on the affected side to healthy side had a good predictive effect on postoperative pain recurrence of PBC. When aspect ratio of foramen ovale on the affected side to healthy side was less than 0.886 3 or area ratio of foramen ovale on the affected side to healthy side was less than 0.869 4, postoperative pain recurrence was common.

CONCLUSIONS

Accurate evaluation of the foramen ovale size of skull base before operation is of great significance in predicting pain recurrence after PBC.

Continuous Ketamine Infusion as a Treatment for Refractory Facial Pain

Complex orofacial pain disorders, such as trigeminal neuralgia (TN) and atypical facial pain (AFP), can be excruciating and debilitating during attacks. Ketamine, an N-methyl-D-aspartate (NMDA) antagonist, is a powerful analgesic that has been used to treat various chronic pain conditions, but its role in treating complex facial pain has only been recently explored. In this retrospective case series, we reviewed the efficacy of continuous ketamine infusion for 12 patients with facial pain refractory to medical treatment. Patients who presented with a diagnosis of TN were more likely to have significant and sustained pain relief after receiving ketamine infusion. By contrast, those who did not respond to the treatment were more likely to have a diagnosis of AFP. The current report suggests a fundamental difference between these two facial pain disorders in their respective underlying pathophysiology and supports the use of continuous ketamine infusion for refractory TN, but not AFP.

Extracranial schwannoma of the maxillary nerve misdiagnosed as trigeminal neuralgia in an elderly patient with schizophrenia - A diagnostic dilemma

The present paper discusses the diagnostic challenges we faced in a 60-year-old woman with a history of schizophrenia, presenting with left unilateral facial pain for the past three months. Based on the elaborate clinical examination and diagnostic nerve blocks, the patient was diagnosed with trigeminal neuralgia (TN) and non-surgical therapy commenced. Further investigations with magnetic resonance imaging (MRI) and ultrasound-guided fine needle aspiration cytology (FNAC) revealed the presence of an extracranial schwannoma involving a branch of the maxillary nerve. The patient was symptomatically relieved after surgical excision of the benign tumor under general anesthesia. Hence, we emphasize the need for special care and attention in psychiatric patients presenting with orofacial pain.

Ultrasound-guided dry needling of masticatory muscles in trigeminal neuralgia - A case series of 35 patients

Background

Trigeminal neuralgia (TGN) is considered a sensory neuropathy. However, reports of pain on chewing/speaking suggest a masticatory myofascial involvement.

Objective

To examine the effect of ultrasound-guided dry needling (USGDN), which deactivates myofascial trigger points in masticatory, neck, and facial muscles on TGN symptoms.

Methods

Charts of 35 patients treated for TGN were retrospectively reviewed. Treatment was USGDN alone or combined with trigeminal ganglion/mandibular nerve pulsed radiofrequency (PRF), followed by yoga mudras to stretch masticatory and facial muscles. Patients were followed for 1-8 years. Outcome parameters were reduction of medications with reduction in neuralgic attack frequency and Numeric Rating Scale (NRS) score.

Results

23 patients (65.7%) received USGDN alone, 12 patients (34.3%) received PRF treatment before USGDN. A significant reduction in the mean (SD) NRS (5.7 [1.2] vs 8.8 [1.6]; P < .001) and neuralgic attack frequency (47 [27] vs 118 [70] attacks/day; P < .001) was seen after PRF compared with baseline, respectively. Following USGDN, the mean (SD) NRS further decreased significantly to 1.0 (0.9) (P < .001). USGDN alone produced a similar improvement in the NRS (8.9 [1.5] at baseline reduced to 0.6 [0.7] post-USGDN; P < .001). Patients in both groups reported a cessation in neuralgic attacks after USGDN. Post-USGDN, 18/27 patients completely discontinued medication, with the mean (SD) carbamazepine dose significantly reducing from 716.7 (260.9) mg/day at baseline to 113.0 (250.2) mg/day post-USGDN (P < .001).

Conclusion

Decisive relief of TGN by USGDN suggests neuromyalgia involving masticatory muscles. Prospective, controlled studies could confirm these findings.

Effect of neuropathic pain on sphenopalatine ganglion block responses in persistent idiopathic facial pain

OBJECTIVES

Management of persistent idiopathic facial pain (PIFP) can be challenging. Sphenopalatine ganglion (SPG) has been the target for the interventional treatment of many facial pain syndromes. However, possible factors that may affect SPG block success are unknown. It was aimed to investigate the effect of neuropathic pain on SPG block outcomes in PIFP, which includes a heterogeneous patient group.

METHODS

All of the patients underwent fluoroscopy-guided SPG block with an injection of 40 mg of 2% lidocaine and 8 mg of dexamethasone. The patients were assigned to 2 groups according to existence of neuropathic pain determined with the DN4 questionnaire score: 19 patients with neuropathic pain (Group 1) and 15 patients without neuropathic pain (Group 2). Preprocedural and postprocedural Visual Analog Scale (VAS) scores were compared between the 2 groups.

RESULTS

The mean age of the patients was 47.65 ± 6.50 years. The average pain duration was 52.95 ± 34.81 weeks. A significantly greater decrease was detected in the VAS scores at 1 week (p = 0.036) and 1 month (p < 0.001) in Group 1 when compared to Group 2. Moreover, the proportion of patients with >50% improvement in the VAS scores at 1 week (p = 0.012) and 1 month (P = 0.017) was significantly lower in Group 1 than in Group 2.

DISCUSSION

SPG block appears as a safe, effective, and rapid method to treat PIFP, especially in cases with neuropathic pain. Neuropathic pain may be a predictor for pain relief in interventional procedures targeting SPG in the treatment of PIFP.

Atypical facial pain after cranioplasty: A too perfect design?: Dolor facial atípico asociado a craneoplastia: ¿un encaje demasiado perfecto?

Cranioplasty is a procedure routinely performed in neurosurgery. It is associated with significant morbidity and several types of postsurgical complications. The most common are infections, bone flap resorption and hematomas. Atypical facial pain has not been documented yet as a potential postoperative complication. We present a case of atypical facial pain reported at inmediate postoperative period after cranioplasty. The pain was refractory to medical treatment and sphenopalatine ganglion block. Eventually, the pain totally disappeared after surgical revision of the cranial implant.

Discomfort and Pain Related to Protective Mask-Wearing during COVID-19 Pandemic

The SARS-CoV-2 pandemic made the use of facemasks mandatory to prevent contact with the virus. Recent studies have revealed that intensive use of facemasks significantly exacerbated pre-existing headaches and triggered de novo headaches. In our experience, some subjects also complain of symptoms of neuropathic pain in the head/facial regions. Until now, the relationship between neuropathic pain and facemasks has not been documented. The aim of the study is to investigate the occurrence of neuropathic pain related to facemask use. It is a cross-sectional survey using a questionnaire, developed following a commonly accepted outcome research methodology. Participants, both health care and non-health care workers, responded to items included in the questionnaire about the type of facemasks, time and manner of wearing them, side effects such as skin lesions, symptoms of neuropathic pain, etc.

Trigeminal Neuralgia Is a Dementia Risk Factor: A Retrospective Cohort Study

Background: Dementia, a worldwide public-health issue, is regarded as a disorder rather than a normal aging process. Trigeminal neuralgia (TN) is a chronic debilitating pain disorder that impairs daily activities. Both are most prevalent in females and in patients older than 50 years. Recent studies reveal that pain and dementia may have a reciprocal interaction with each other. Objective: In response, we estimated whether adults with TN have an increased dementia risk. Methodology: By means of Taiwan's National Health Insurance Research Database, between 1996 and 2010, 762 patients aged over 50 years in the TN group were matched with 3048 patients in the non-TN group at a ratio of 1:4. Kaplan-Meier method and Cox proportional hazard regression models were also used to determine the cumulative incidence and compare the hazard ratios of dementia in each group. Results: The incidence of dementia was higher in the TN group compared to the non-TN group. After adjusting for covariates, the TN group had a 4.47-fold higher risk of dementia compared to the non-TN group. Additionally, the impact of TN on dementia risk was larger in young-aged patients than in old-aged patients. As well, the age at the time of dementia diagnosis was younger in the TN group compared to the non-TN group. Conclusions: TN is a dementia risk factor. Given the lack of a curative therapy for dementia, early identification of TN patients may help to prevent dementia sequelae.

Complex Neurovascular Syndromes: Is the Compressing Vessel Alone the Culprit?

Objective To describe and correlate the clinical, radiological, and intraoperative findings in patients with refractory neurovascular syndromes (NVS) not responding to conventional medical management and to determine the surgical outcome of the microvascular decompression (MVD) procedure.

Methods Medical records of 17 patients with NVS (trigeminal neuralgia [TN] = 14 and hemifacial spasm = 3) who underwent surgery for symptom relief from January 2018 to July 2021 with follow-up data (1–36 months) were retrospectively analyzed. Patient demographics (age, sex), clinical features (site, duration of symptoms, distribution), magnetic resonance imaging (MRI) findings, micro-neurosurgical details (type of surgery, obstructive vessel), and postoperative outcome and complications were recorded.

Statistical Analysis Descriptive analysis was performed. Variables were presented as either mean and standard deviation or frequency and percentages.

Results The mean (standard deviation) age of patients in our study cohort was 52.6 (12.2) years. TN was common in females (64.3%). The mean duration of symptoms was longer in patients with hemifacial spasms than in patients with TN (3.3 vs. 2.7 years). While the right side was commonly affected in TN (64.3%), the left side was common in hemifacial spasm (66.7%). Most common neuralgia symptoms were distributed along the V2V3 (maxillary and mandibular division) branches (42.9%). MRI revealed neurovascular conflict in nine patients, epidermoid tumor in three patients, classical vestibular schwannoma in two patients, and short cisternal segments in three patients. Intraoperatively, superior cerebellar artery was the main offending vessel in TN followed by anterior inferior cerebellar artery (AICA) and venous compression, while tortuous vertebral artery and AICA along with thickened entangled arachnoid were seen in hemifacial spasms. Almost all patients (88.2%) reported immediate postoperative complete pain relief. One patient died secondary to chest infection after a month.

Conclusion Arachnoid entanglement around the neurovascular bundle along with vascular compression over the cranial nerves is the main cause of NVS. Advanced micro-neurosurgical techniques used in MVD achieve excellent outcomes with improved quality of life. However, identifying the refractory NVS not responding to conventional medical management and early surgical management are paramount.

Clinical Analysis of the Treatment of Primary Trigeminal Neuralgia by Percutaneous Balloon Compression

Purpose

To summarize the technical points and clinical effects of percutaneous balloon compression (PBC) in the treatment of primary trigeminal neuralgia.

Methods

The clinical data of 13 patients with trigeminal neuralgia who received PBC from April 2020 to July 2021 were retrospectively analyzed. VAS, VRS-4 and PPI were used to evaluate the postoperative pain relief. Different postoperative complications were analyzed.

Results

All patients had a smooth operation, the inflation volume of the balloon was 0.7 ml, the average compression time was 120 s, and there was no balloon rupture during the operation. On the day after operation, 12 patients (92.3%) had complete pain relief, and 1 patient (7.7%) was not satisfied with pain relief, but the pain disappeared 2 weeks after the operation. After operation, there were 12 patients with facial numbness in the affected side (92.3%), 3 patients with masseter muscle weakness (23.0%), 1 patient with herpes around the mouth (7.6%), and 1 patient with diplopia (7.6%).

Conclusion

PBC is an effective minimally invasive surgical method for the treatment of primary trigeminal neuralgia. It is suitable for the elderly and infirm people, those who cannot tolerate general anesthesia or are afraid of surgery, and patients who had undergone surgery but relapsed after surgery. However, it is necessary to pay attention to the serious facial numbness and postoperative masticatory weakness. These discomforts are generally relieved after half a year.

Persistent idiopathic facial pain treated with botulinum toxin and pulsed radiofrequency of infraorbital nerve: a case report

Persistent idiopathic facial pain is a rare and difficult condition to treat. Several pharmacological, non-pharmacological, and invasive treatment options have been used, with varying results. We report the case of a patient with intractable persistent idiopathic facial pain who responded favorably to a combination of botulinum toxin injections and pulsed radiofrequency treatment of the infraorbital nerve.

Is this really trigeminal neuralgia? Diagnostic re-evaluation of patients referred for neurosurgery

OBJECTIVES

Patients with facial pain are sometimes referred for neurosurgical treatment with a poorly documented diagnosis of trigeminal neuralgia. In such cases, neurosurgery will usually not be helpful. We conducted a re-evaluation of the diagnosis in patients referred for neurosurgical treatment of presumed trigeminal neuralgia. Our objective was to find out why and how often misdiagnosis occurred.

METHODS

A retrospective study was done in consecutive first-time patients referred for trigeminal neuralgia to our outpatient clinic in 2019. We used five ICHD-3-based clinical criteria to verify or exclude the diagnosis. In patients where trigeminal neuralgia was excluded, we established a diagnosis for their facial pain based upon medical history and a physical examination by a neurosurgeon - often supplemented with examination by an oral surgeon.

RESULTS

Thirty-eight patients were referred for presumed trigeminal neuralgia. Only 17 of them fulfilled the five criteria and were diagnosed with trigeminal neuralgia. In 20 of the remaining 21 patients trigeminal neuralgia could be clearly excluded, while one of the patients had a periodontitis closely mimicking trigeminal neuralgia. In 14 of the 21 patients we diagnosed temporomandibular dysfunction or dental conditions. MRI scans had detected low-grade neurovascular contacts in 13 of the 21 patients, a finding that was clearly overestimated by the referring neurologists in seven patients.

CONCLUSIONS

Overdiagnosis of trigeminal neuralgia was common in patients referred for neurosurgery, mostly due to insufficient clinical evaluation combined with an overestimation of MRI-detected NVCs. The clinical diagnosis should be critically re-evaluated before recommending neurosurgery to patients referred for presumed trigeminal neuralgia.

Comparison of efficacy and safety of complementary and alternative therapies for primary trigeminal neuralgia: A protocol for a Bayesian network meta analysis

BACKGROUND

Primary trigeminal neuralgia (PTN) is a type of peripheral neuralgia that seriously affects people's lives. In recent years, complementary therapies and alternative therapies have played a significant role in treating PTN. However, there is a lack of comparison among all the complementary and alternative therapies at present. Thus, the aim of this study is to discuss the efficacy and safety of diverse complementary and alternative therapies by Bayesian network meta-analysis (NMA).

METHODS

We will retrieve the Chinese and English databases to gather related randomized controlled trials (RCTs) of complementary and alternative therapies for treating PTN. The deadline is November 2020. Two independent researchers will be in charge of screening qualified literature, extracting data, and independently evaluating bias risks involved in the research. Pairwise meta-analysis and Bayesian network meta-analysis will be performed to assess all evidence. Then, we will use STATA16.0 as well as WinBUGS1.4.3 software for data analysis. Besides, the quality of NMA evidence will be classified by grading of recommendations assessment development and evaluation (GRADE).

RESULTS

This study will compare and rank the efficacy and safety of different complementary and alternative therapies in treating primary trigeminal neuralgia.

CONCLUSION

Complementary and alternative therapies play an essential role in treating primary trigeminal neuralgia. We expect our study will furnish meaningful evidence support for clinicians and patients.

PROTOCOL REGISTRATION NUMBER

INPLASY2020120026.

ETHICAL APPROVAL

Since the study is based on published or registered RCTs, ethical approval and patient informed consent are abandoned.