Update on Interventional Management of Neuropathic Pain: A Delphi Consensus of the Spanish Pain Society Neuropathic Pain Task Force

Background and Objectives: Interventional management of neuropathic pain (NP) is available to the patients who do not obtain satisfactory pain relief with pharmacotherapy. Evidence supporting this is sparse and fragmented. We attempted to summarize and critically appraise the existing data to identify strategies that yield the greatest benefit, guide clinicians, and identify areas that merit further investigation. Material and Methods: A two-round Delphi survey that involved pain clinic specialists with experience in the research and management of NP was done over an ad hoc 26-item questionnaire made by the authors. Consensus on each statement was defined as either at least 80% endorsement or rejection after the 2nd round. Results: Thirty-five and 29 panelists participated in the 1st and 2nd round, respectively. Consensus was reached in 20 out of 26 statements. There is sufficient basis to treat postherpetic neuralgias and complex regional pain syndromes with progressive levels of invasiveness and failed back surgery syndrome with neuromodulation. Radiculopathies and localized NP can be treated with peripheral blocks, neuromodulation, or pulsed radiofrequency. Non-ablative radiofrequency and non-paresthetic neuromodulation are efficacious and better tolerated than ablative and suprathreshold procedures. Conclusions: A graded approach, from least to most invasive interventions has the potential to improve outcomes in many patients with common refractory NP conditions. Preliminary promising data warrant further research on new indications, and technical advances might enhance the safety and efficacy of current and future therapies.

Factors Related to Hemifacial Spasm Recurrence in Patients Undergoing Microvascular Decompression—A Systematic Review and Meta-Analysis

There is a lack of knowledge about the factors associated with the recurrence of hemifacial spam (HFS) following an initially successful microvascular decompression (MVD) surgery. The aim of the present study was to systematically review the pertinent literature and carry out a meta-analysis of factors linked to HFS recurrence in patients undergoing initially successful MVD treatment. An online literature search was launched on the PubMed/Medline and Scopus databases. The following data were collected: sex, age at surgery, affected side, reported improvement after surgery, presence of post-operatory facial weakness, symptom duration, offender vessels, and data obtained from intraoperative neurophysiological monitoring. Upon full-text review, eight articles were included, studying 1105 patients, of which 64 (5.7%) reported recurrence after MVD surgery for hemifacial spasm. There was a statistically significant increased incidence of HFS recurrence in patients with the persistence of lateral spread response (LSR after surgery (OR 9.44 (95% CI 1.69–52.58) p 0.01), while those patients experiencing a shorter disease duration before going to surgery were significantly less prone to experiencing disease recurrence (OR 0.11 (95% CI 0.03–0.46) p 0.002). The remaining examined factors did not result as significantly associated with the risk of recurrence. The funnel plots were largely symmetrical for each variable studied. Taken together, the results of our meta-analysis seem to suggest that short-term symptom duration is a protective factor against HFS recurrence after MVD surgery, while LSR persistence is a negative prognostic factor. Well-designed randomized controlled clinical trials with a long follow-up are expected to further explore therapeutic alternatives for HFS recurrence.

Orofacial pain disorders: An overview and diagnostic approach

Background:

Non-dental orofacial pain disorders are not uncommon, but idiopathic or primary facial pain syndromes are rare. Inadequate recognition of these disorders usually leads to unsatisfactory and unmet treatment needs.

Methods:

We conducted a narrative review with a literature search in PubMed until December 2021, focusing on current guidelines and the recently published International Classification of Orofacial Pain (ICOP).

Results:

In this paper, we provide an updated overview of the common orofacial pain disorders following the ICOP, covering the classification, epidemiology, pathophysiology, clinical approaches, and treatment options. Additionally, we propose a pragmatic approach focusing on the attack duration to improve distinguishing orofacial disorders.

Conclusion:

The introduction of ICOP offers the opportunity to better coordinate and concentrate scientific efforts, which lays the foundation for the identification of the disease mechanism of facial pain disorders and the optimization of the currently still insufficient therapeutic strategies.

A Review of Medical and Surgical Options for the Treatment of Facial Pain

Facial pain is a common medical complaint that is easily misdiagnosed. As a result, this pain often goes mistreated. Despite this, there are a variety of pharmacologic, surgical, and neuromodulatory options for the treatment of facial pain. In this review, the authors detail the forms of facial pain and their treatment options. They discuss the common medications used in the first-line treatment of facial pain and the second-line surgical and neuromodulatory options available to patients when pharmacologic options fail.

Intravenous lacosamide and phenytoin for the treatment of acute exacerbations of trigeminal neuralgia: A retrospective analysis of 144 cases

Background

Scant evidence is available on the use of intravenous pain treatment in acute exacerbations of trigeminal neuralgia. The aim of this descriptive study was to evaluate the effectiveness and security of intravenous lacosamide and phenytoin in the treatment of acute trigeminal neuralgia pain.

Methods

We reviewed patients who attended the emergency department of a tertiary hospital between 2012 and 2020 for exacerbations of trigeminal neuralgia pain and were treated with either intravenous phenytoin or lacosamide for the first time. Primary endpoints were pain relief and adverse effects during the hospital stay. A comparative analysis between both treatment groups was performed.

Results

We studied 144 episodes in 121 patients (median age 61 years, 66.1% women). Trigeminal neuralgia etiology was secondary in 9.9%. Pain relief was observed in 77.8% of 63 patients receiving lacosamide infusions, and adverse effects in 1.6%. Pain relief was observed in 72.8% of 81 phenytoin infusions and adverse effects in 12.3%, all mild. No difference was observed in pain relief between groups, but the proportion of adverse effects was significantly different (p = 0.023). Statistically significant differences were also detected in readmissions within six months, time to readmission, and pain relief status at first follow-up visit.

Conclusion

Intravenous lacosamide and phenytoin can be effective and safe treatments for acute pain in trigeminal neuralgia. According to our series, lacosamide might be better tolerated than phenytoin and lead to lower readmissions and sustained pain relief.

Intravenous fosphenytoin as treatment for acute exacerbation of trigeminal neuralgia: A prospective systematic study of 15 patients

INTRODUCTION

Intravenous fosphenytoin is widely used for acute exacerbation of trigeminal neuralgia, however, few studies have investigated this treatment. We aimed to examine the efficacy and side effects of initial intravenous fosphenytoin plus oral tapering of phenytoin for exacerbation of trigeminal neuralgia.

METHODS

Consecutive patients with primary trigeminal neuralgia were included in this prospective observational 90-days follow-up study. Data were collected using standardized interviews before, at 24 hours, day 7, 30 and 90 post loading dose. The primary outcome was the proportion of responders defined as a 50% reduction in pain intensity 24 hours post loading dose.

RESULTS

We included 15 patients. Nine patients (60%) were responders. Pain intensity 24 hours post loading dose was reduced by 5.00 points on the numerical rating scale (p < 0.001), and at day 7 by 5.5 points (p < 0.001). The most common side effects were hypotension and dizziness.

CONCLUSION

Intravenous fosphenytoin relieves trigeminal neuralgia pain in most patients and provides a window for titrating prophylactic trigeminal neuralgia medications or planning neurosurgery. The decision to administer intravenous fosphenytoin should be taken with support from trigeminal neuralgia experts and involves considerations of co-morbidities and other treatment options for acute exacerbation of trigeminal neuralgia.Clinical Trial: Preregistered (ClinicalTrials.gov Identifier: NCT03712254.

Long-term Recurrence-free Survival and Complications of Percutaneous Balloon Compression and Radiofrequency Thermocoagulation of Gasserian Ganglion for Trigeminal Neuralgia:A Retrospective Study of 1313 Cases

OBJECTIVE

To estimate long-term recurrence, complications after percutaneous balloon compression (PBC) and radiofrequency thermocoagulation (RFT) of gasserian ganglion among a large sample of patients with trigeminal neuralgia (TN) during a long-term follow-up.

METHODS

A retrospective analysis of 1313 patients undergoing PBC or RFT for the treatment of TN was conducted from 2006 to 2020. Recurrence-free survival (RFS) was assessed by Kaplan-Meier method. Complications including facial numbness, corneal reflex decrease and masseter weakness were also estimated.

RESULTS

For patients who received first initial PBC and RFT, the median RFS was 130.1 months (95%CI: 124.4, 135.9) and 123.3 months (95%CI: 117.6, 128.9) in PBC and RFT group with log-rank p=0.108. The RFS rate was respectively 90.6% (95%CI: 88.1%-93.3%) and 91.4% (95%CI: 89.1%-93.7%) at 1 year, 84.6% (95%CI: 81.4%-87.8%) and 83.3% (95%CI: 80.3%-86.3%) at 3 years, 81.5% (95%CI: 78.1%-85.0%) and 78.6 % (95%CI: 75.2%-81.9%) at 5 years, 71.5% (95%CI: 67.5%-75.5%) and 64.8% (95%CI: 61.0%-68.7%) at 10 years in two groups. No significant difference was observed in facial numbness degree between two groups after procedure. Compared with PBC group, ophthalmic complication prevalence was higher in RFT group (9.6%) (p=0.001). However, masseter weakness incidence was lower (10.7%) than that in PBC group (24.0%) with p<0.001.

CONCLUSIONS

Patients with TN seemed to attain similar long-term benefit from PBC and RFT, especially in elderly. However, in order to reduce postoperative complications, PBC provided a safer and alternative for treating TN involving ophthalmic division, whereas RFT could be employed as a preferred regimen for maxillary and mandibular TN.

Surgical treatment for Trigeminal neuralgia

Various treatments for trigeminal neuralgia (TN) are known to yield initial satisfactory results; however, the surgical treatment has excellent long-term outcomes and a low recurrence rate. Surgical treatment addresses the challenge of vascular compression, which accounts for 85% of the causes of TN. As for surgical treatment for TN, microvascular decompression (MVD) has become the surgical treatment of choice after Peter J. Jannetta reported the results of MVD surgery in 1996. Since then, many studies have reported a success rate of over 90% for the initial surgical treatment. Most MVDs aim to separate (decompress) the culprit vessel from the trigeminal nerve. To increase the success rate of surgery, accurate indications for MVD and management of the offender vessels without complications are critical. In addition, if there is no vascular compression, partial sensory rhizotomy or internal neurolysis can be performed to improve surgical outcomes.

Extracranial Radiofrequency Treatment for Painful Tic Convulsif Syndrome Under Local Anesthesia

Introduction

Painful tic convulsif syndrome is ipsilateral facial trigeminal neuralgia combined with hemifacial spasm, which is relatively rare in the clinic. Microvascular decompression is currently considered to be an effective treatment. We report extracranial radiofrequency treatment of painful tic convulsif syndrome under local anesthesia, a technique which provides a safer and more economical treatment for this kind of patient.

Case Presentation

We report a case of painful tic convulsif syndrome which was treated with extracranial radiofrequency therapy of the trigeminal nerve and facial nerve. After operations, the symptoms of pain and spasm were relieved immediately, but the right facial numbness and facial paralysis (House–Brackmann grade III) were left. The facial paralysis was completely relieved after 3 months of follow-up, and there was no recurrence of trigeminal neuralgia or hemifacial spasm after 35 months.

Discussion

Painful tic convulsif syndrome is a combination of ipsilateral facial trigeminal neuralgia and hemifacial spasm, which is relatively rare in the clinic. So far, only one treatment method of microvascular decompression has been reported for the disease. We report the first case of CT-guided extracranial radiofrequency therapy for painful tic convulsif syndrome.

Conclusion

Extracranial radiofrequency therapy can provide safe and economical treatment for patients with painful tic convulsif syndrome.

Thinking Outside the Tooth: Diagnosis and Management of Patients with Neuropathic Orofacial Pain

Nonodontogenic orofacial pain exists, and diagnosis and management of those conditions can be challenging. This article highlights and discusses how to take a complete and systematic pain history and the important red flags to recognize in patients presenting with perplexing nonodontogenic orofacial pain. Cause and epidemiology, clinical presentation, clinical evaluation and diagnosis, and management options for common neuropathic pain conditions are included. Neuralgia and neuropathic pain conditions and red flags as secondary cause of orofacial pain are more common in older-aged patients.

The Molecular Basis and Pathophysiology of Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a complex orofacial pain syndrome characterized by the paroxysmal onset of pain attacks in the trigeminal distribution. The underlying mechanism for this debilitating condition is still not clearly understood. Decades of basic and clinical evidence support the demyelination hypothesis, where demyelination along the trigeminal afferent pathway is a major driver for TN pathogenesis and pathophysiology. Such pathological demyelination can be triggered by physical compression of the trigeminal ganglion or another primary demyelinating disease, such as multiple sclerosis. Further examination of TN patients and animal models has revealed significant molecular changes, channelopathies, and electrophysiological abnormalities in the affected trigeminal nerve. Interestingly, recent electrophysiological recordings and advanced functional neuroimaging data have shed new light on the global structural changes and the altered connectivity in the central pain-related circuits in TN patients. The current article aims to review the latest findings on the pathophysiology of TN and cross-examining them with the current surgical and pharmacologic management for TN patients. Understanding the underlying biology of TN could help scientists and clinicians to identify novel targets and improve treatments for this complex, debilitating disease.

Microvascular Decompression for Trigeminal Neuralgia Caused by Venous Offending on the Ventral Side of the Root Entrance/Exit Zone: Classification and Management Strategy

Background

Trigeminal neuralgia (TGN) is typically caused by an offending artery (OA) but may also involve an offending vein. Venous offending on the ventral side of the root entrance/exit zone (VO-VREZ) is particularly challenging.

Objective

To analyze the rate and pattern of VO-VREZ and propose management strategy accordingly.

Methods

VO-VREZ was classified into 3 types based on its anatomical relationship with a nerve root (A, the vein was covered by the nerve root entirely; B, the vein was lateral to the nerve root; and C, the vein penetrated the nerve root) and 3 groups based on the absence/presence of offending artery (I, no OA; II, suspected OA; and III, definitive OA).

Results

The analysis included 143 cases with complete follow-up. Type A, B, and C accounted for 11.9, 31.5, and 56.6% of the cases, respectively. Group I, II, and III accounted for 24.5, 26.6, and 49.0%, respectively. Most group I VO-VREZ cases (26 out of 31) were managed with coagulation followed by division. Most group II VO-VREZ cases (31 out of 38) were decompressed with shredded Teflon interposition. Group III VO-VREZ was left in place in all 70 cases. Immediate pain relief was achieved in all cases. Temporary hemifacial hypesthesia occurred in 21 patients (14.7%), among which 14 were managed with Teflon decompression. Within the 4.5-year median follow-up, pain recurred in 11 patients (7.7%), but all with lesser intensity.

Conclusion

VO-VREZ is not uncommon in patients with TGN. Different management strategy should be chosen according to the anatomical feature and the absence/presence of arterial conflict.

Trigeminal microvascular decompression for short-lasting unilateral neuralgiform headache attacks

A significant proportion of patients with short-lasting unilateral neuralgiform headache attacks (SUNHA) are refractory to medical treatments. Neuroimaging studies have suggested a role for ipsilateral trigeminal neurovascular conflict with morphological changes in the pathophysiology of this disorder. We present the outcome of an uncontrolled open-label prospective single centre study conducted between 2012 and 2020, to evaluate the efficacy and safety of trigeminal microvascular decompression in refractory chronic SUNHA with magnetic resonance imaging evidence of trigeminal neurovascular conflict ipsilateral to the pain side. Primary endpoint was the proportion of patients who achieved an "excellent response", defined as 90-100% weekly reduction in attack frequency, or "good response", defined as a reduction in weekly headache attack frequency between 75% and 89% at final follow-up, compared to baseline. These patients were defined as responders. The study group consisted of 47 patients of whom 31 had SUNCT and 16 had SUNA (25 females, mean age ± SD 55.2 years ± 14.8). Participants failed to respond or tolerate a mean of 8.1 (±2.7) preventive treatments pre-surgery. Magnetic resonance imaging of the trigeminal nerves (n = 47 patients, n = 50 symptomatic trigeminal nerves) demonstrated ipsilateral neurovascular conflict with morphological changes in 39/50 (78.0%) symptomatic nerves and without morphological changes in 11/50 (22.0%) symptomatic nerves. Post-operatively, 37/47 (78.7%) patients obtained either an excellent or a good response. Ten patients (21.3%, SUNCT = 7 and SUNA = 3) reported no post-operative improvement. The mean post-surgery follow-up was 57.4 ± 24.3 months (range 11-96 months). At final follow-up, 31 patients (66.0%) were excellent/good responders. Six patients experienced a recurrence of headache symptoms. There was no statistically significant difference between SUNCT and SUNA in the response to surgery (p = 0.463). Responders at the last follow-up were however more likely not to have interictal pain (77.42% vs 22.58%, p = 0.021) and to show morphological changes on the magnetic resonance imaging (78.38% vs 21.62%, p = 0.001). The latter outcome was confirmed in the Kaplan Meyer analysis, where patients with no morphological changes were more likely to relapse overtime compared to those with morphological changes (p = 0.0001). All but one patient who obtained an excellent response without relapse, discontinued their preventive medications. Twenty-two post-surgery adverse events occurred in 18 patients (46.8%) but no mortality or severe neurological deficit was seen. Trigeminal microvascular decompression may be a safe and effective long-term treatment for short-lasting unilateral neuralgiform headache attacks patients with magnetic resonance evidence of neurovascular conflict with morphological changes.

Robot-Assisted Percutaneous Balloon Compression for Trigeminal Neuralgia: Technique Description and Short-Term Clinical Results

Objective

Percutaneous balloon compression (PBC) is a minimally invasive treatment for trigeminal neuralgia (TG) with a favorable cost-effectiveness ratio, but this technique has a steep learning curve. This study presents our initial clinical experience of robot-assisted PBC using a neurosurgical robot on six consecutive patients with TG.

Methods

We fixed the patient's head with a skull clamp and connected it with the linkage arms of a Sinovation^® neurosurgical robot, which was then registered using four bone fiducials by the robotic pointer. The puncture needle was positioned at the entry point on the skin using a robotic arm and advanced to the target point after the skin had been incised with a pointed surgical blade. This procedure was repeated for a second trajectory. A balloon was then advanced and inflated using 0.3 ml of a contrast agent. Upon injection of 0.6 ml contrast agent, the ganglion was kept compressed for 120 s. After removal of the balloon and puncture needle, compression of the face was performed to achieve hemostasis.

Results

All patients achieved immediate pain relief following PBC. No permanent or severe complications were registered, and there was no pain recurrence in any of the patients during the follow-up period.

Conclusions

Despite requiring a longer time for preoperative preparation, robot-assisted PBC provided a high degree of accuracy and safety, and it can also shorten the learning curve for surgeons unfamiliar with PBC. Robot-assisted surgical approaches should be further developed and adopted for PBC.

Short-Term Functional and Morphological Changes in the Primary Cultures of Trigeminal Ganglion Cells

Several studies have proved that glial cells, as well as neurons, play a role in pain pathophysiology. Most of these studies have focused on the contribution of central glial cells (e.g., microglia and astrocytes) to neuropathic pain. Likewise, some works have suggested that peripheral glial cells, particularly satellite glial cells (SGCs), and the crosstalk between these cells and the sensory neurons located in the peripheral ganglia, play a role in the phenomenon that leads to pain. Nonetheless, the study of SGCs may be challenging, as the validity of studying those cells in vitro is still controversial. In this study, a research protocol was developed to examine the potential use of primary mixed neuronal–glia cell cultures obtained from the trigeminal ganglion cells (TGCs) of neonate mice (P10–P12). Primary cultures were established and analyzed at 4 h, 24 h, and 48 h. To this purpose, phase contrast microscopy, immunocytochemistry with antibodies against anti-βIII-tubulin and Sk3, scanning electron microscopy, and time-lapse photography were used. The results indicated the presence of morphological changes in the cultured SGCs obtained from the TGCs. The SGCs exhibited a close relationship with neurons. They presented a round shape in the first 4 h, and a more fusiform shape at 24 h and 48 h of culture. On the other hand, neurons changed from a round shape to a more ramified shape from 4 h to 48 h. Intriguingly, the expression of SK3, a marker of the SGCs, was high in all samples at 4 h, with some cells double-staining for SK3 and βIII-tubulin. The expression of SK3 decreased at 24 h and increased again at 48 h in vitro. These results confirm the high plasticity that the SGCs may acquire in vitro. In this scenario, the authors hypothesize that, at 4 h, a group of the analyzed cells remained undifferentiated and, therefore, were double-stained for SK3 and βIII-tubulin. After 24 h, these cells started to differentiate into SCGs, which was clearer at 48 h in the culture. Mixed neuronal–glial TGC cultures might be implemented as a platform to study the plasticity and crosstalk between primary sensory neurons and SGCs, as well as its implications in the development of chronic orofacial pain.

Acupuncture Methods for Primary Trigeminal Neuralgia: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

Background

Primary trigeminal neuralgia (PTN) is a clinical refractory disorder characterized by excruciating pain that severely impacts the quality of life. Several studies have shown that acupuncture can improve PTN pain. However, the comparative efficacy and safety of acupuncture are unknown. Herein, a systematic review was conducted to compare the efficacy and safety of various acupuncture methods for PTN treatment.

Methods

Relevant randomized controlled trials (RCTs) published up to 1 August 2021 were obtained from PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science Core Collection, Chinese National Knowledge Infrastructure, Chinese Biomedical Literature Database, CQVIP Database, Wanfang Database, Allied and Alternative Medicine Database, and related registration platforms. Two authors independently selected the studies and obtained data. Cochrane Handbook was used to assess the methodological quality. We put the pain relief as the primary outcome and the response rate and adverse events as the secondary outcomes. Review Manager v5.3, ADDIS v1.16.8, and STATA v15.0 software were used for data analysis. The intraclass correlation coefficient was used to assess the consistency of the two investigators.

Results

A total of 58 RCTs with 4,126 participants were obtained. The meta-analysis indicated that five acupuncture methods were superior to conventional medicine (carbamazepine) in pain reduction intensity and response rate. Meanwhile, electronic acupuncture plus manual acupuncture was the most effective therapy since it reduced pain intensity in 11 methods and improved the response rate in 10 interventions. Moreover, six interventions had acceptable adverse events, and none of the included studies reported severe adverse events. However, most pieces of evidence were ranked as critically low.

Conclusion

These findings show that acupuncture methods can be effective and safe for PTN. Moreover, electronic acupuncture plus manual acupuncture maybe the best acupuncture treatment for PTN and should be administered to PTN patients. However, additional well-designed and high-quality RCTs should be conducted to verify the above findings in the future. The systematic review is registered with CRD42020221456.

Treatment Strategies for Different Types of Intraneural Offending Vessels in Microvascular Decompression Surgery for Trigeminal Neuralgia: An Analytic Report of 58 Cases

BACKGROUND

Microvascular decompression (MVD) surgery is the treatment of choice for trigeminal neuralgia (TGN). However, decompression becomes difficult when the offending vessel penetrates the trigeminal nerve root.

OBJECTIVE

To estimate the rates and patterns of different types of intraneural offending vessels in patients with TGN for MVD and to discuss respective management strategies.

METHODS

All patients with TGN undergoing MVD in our center from January 1, 2015, to December 31, 2019, were analyzed retrospectively. The intraneural offending vessels included veins and arteries. The postoperative pain relief rate, complications, and recurrences were evaluated.

RESULTS

Of the 302 TGN cases, the intraneural offending vessels were identified in 58 of the cases (19.2%). The 9 cases (15.5%) of intraneural offending arteries were decompressed using shredded Teflon wrapping interposition. Of the 49 cases (84.5%) of intraneural offending veins (INOVs), 29 were not considered true offending vessels, and the treatment only addressed the offending artery in these patients. Of the remaining 20 INOVs, 15 were electrocoagulated and divided, and 5 were decompressed with shredded Teflon. Complete pain relief was achieved in all 58 patients. However, the pain recurred in 5 patients (8.6%), and transient hemifacial numbness occurred in 4 patients (6.9%).

CONCLUSION

Intraneural offending vessels requiring treatment are uncommon and are seen in less than 1 in 10 patients undergoing MVD for TGN. For intraneural offending artery, decompression by shredded Teflon wrapping interposition is recommended. Management of the INOV depends on the individual situations, and the management includes sacrifice, wrapping decompression, or leaving them untreated.

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.

Predictive and prognostic factors for outcome of microvascular decompression in trigeminal neuralgia

BACKGROUND

Trigeminal neuralgia (TN) is a disease characterized by recurring, short-lived, electric shock-like pain experienced on one side of the face. Microvascular decompression (MVD) is one of the most effective surgical interventions for resolving TN caused by neurovascular compression. This study aimed to determine the predictive and prognostic factors of surgical outcomes.

METHODS

This retrospective cohort study enrolled patients diagnosed with TN who underwent MVD at our hospital during 2013-2019. The demographic information, pain character, peri-operative Barrow Neurological Institute (BNI) scale, medication, operative finding were recorded. And the outcome was Outcomes were divided into drug-free and drug-dependent group. Predisposing factors for each outcome were analyzed by one-way analysis of variance, followed by a Mann-Whitney U test or Kruskal-Wallis test.

RESULTS

A total of 104 consecutive patients received MVD to treat TN, and 88 patients were enrolled in this study. The overall postoperative drug-free outcome was 72.7%. A significant difference in drug-free outcomes was observed for patients with typical TN (80.8%) compared with patients with atypical TN (33.33%, p = 0001). When severe venous compression was encountered during MVD, the drug-free outcome fell to 50% (10/20, p = 0.009). The Mann-Whitney U test indicated typical TN as a positive predictive factor of a drug-free outcome, whereas severe venous compression was a negative predictive factor. The patients with preoperative BNI score of 4 had better improvement than others (p = 0.045). Age, onset duration, and arterial loop had no specific difference in this study.

CONCLUSION

In our study, atypical TN and severe venous compression were associated with poor outcomes. Regrouping atypical TN into precise diagnosis represents an immediate priority according to our result. The preoperative BNI score could be used as an effective predictive tool for the outcome of MVD surgery.

Effectiveness and safety of acupuncture for treating trigeminal neuralgia associated anxiety and depression: A protocol for systematic review and meta-analysis

BACKGROUND

Patients with trigeminal neuralgia (TN) often develop a terrible fear of triggering pain, which may lead to anxiety and depression, exerting a negative effect on their quality of life. This protocol is carried out to comprehensively explore the effectiveness and safety of acupuncture for treating anxiety and depression induced by TN.

METHODS

Randomized control trials involving acupuncture for treating patients with anxiety and depression caused by TN will be searched in eight electric databases, including PubMed, Web of Science, EMBASE, Cochrane Central Register of Controlled Trials, Chinese National Knowledge Infrastructure, Chinese Biomedical Literature Database, Wanfang Database and Technology Periodical Database (VIP). In addition, studies that were reported in Chinese or English will be considered. Studies selection, data extraction and risk of bias assessment of the included studies will be conducted independently by two reviewers. Quality of the included studies will be performed according to the Cochrane Risk of Bias tool. Meanwhile, the level of evidence for results will be assessed by using the Grading of Recommendations Assessment, Development, and Evaluation method. The primary outcomes will be the Hamilton Anxiety/Depression Scale or Zung Self-Rating Anxiety/Depression Scale, secondary outcomes will be the visual analog score, numerical rating score, SF-36, and adverse events. All analyses will be conducted by using the RevMan software V5.3.

RESULTS

A high-quality synthesis of current evidence of acupuncture for TN patients associated with anxiety and depression will be provided in this study.

CONCLUSION

This systematic review will offer comprehensive evidence of acupuncture on specific outcomes induced by TN and TN-related anxiety and depression.

TRIAL REGISTRATION

PROSPERO registration number: CRD42020219775.

Neurapraxia in patients with trigeminal neuralgia but no identifiable neurovascular conflict during microvascular decompression: a retrospective analysis of 26 cases

Background

Microvascular decompression (MVD) is the first choice in patients with classic trigeminal neuralgia (TGN) that could not be sufficiently controlled by pharmacological treatment. However, neurovascular conflict (NVC) could not be identified during MVD in all patients. To describe the efficacy and safety of treatment with aneurysm clips in these situations.

Methods

A total of 205 patients underwent MVD for classic TGN at our center from January 1, 2015 to December 31, 2019. In patients without identifiable NVC upon dissection of the entire trigeminal nerve root, neurapraxia was performed using a Yasargil temporary titanium aneurysm clip (force: 90 g) for 40 s (or a total of 60 s if the process must be suspended temporarily due to bradycardia or hypertension).

Results

A total of 26 patients (median age: 64 years; 15 women) underwent neurapraxia. Five out of the 26 patients received prior MVD but relapsed. Immediate complete pain relief was achieved in all 26 cases. Within a median follow-up of 3 years (range: 1.0–6.0), recurrence was noted in 3 cases (11.5%). Postoperative complications included hemifacial numbness, herpes labialis, masseter weakness; most were transient and dissipated within 3–6 months.

Conclusions

Neurapraxia using aneurysm clip is safe and effective in patients with classic TGN but no identifiable NVC during MVD. Whether this method could be developed into a standardizable method needs further investigation.

Prevalence of trigeminal neuralgia in multiple sclerosis: A systematic review and meta-analysis

BACKGROUND

The prevalence of Trigeminal Neuralgia (TN) in patients diagnosed with multiple sclerosis (MS) is insufficiently understood and controversially reported. This study focused on providing a better understanding of the prevalence of TN in MS patients.

METHOD

We systematically searched PubMed, Scopus, EMBASE, Web of Science, and Google Scholar to identify studies published from January 1, 1990, to December 30, 2020. We included studies reporting the TN prevalence among MS patients and exclude case reports/series and editorial studies, review studies, and non-English written articles. We used pooled prevalence estimates to determine the TN prevalence among MS patients.

RESULTS

Pooled overall TN prevalence among 19 studies and 30,348 MS patients was estimated as 3.4% (95% CI: 1.5%-5.9%) with a high level of heterogeneity among studies (I2=98.92%; p<0.001). The pooled prevalence of TN in male and female patients across 9 surveys was 2.4% (95% CI: 0.5%-5.4%) and 3.8% (95% CI: 0.8%-8.7%), respectively. No heterogeneity between the two groups was observed (p = 0.558). A meta-regression was performed to explore the source of the heterogeneity. None of the candidate covariates, including the year of a study publication, the sample size, the average age of patients, and the disease duration, were significant in the model.

CONCLUSION

Our results showed that TN is a common problem among patients with MS, predominantly male patients. Future studies should target the general prevalence of pain in MS patients.

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.

[Brivaracetam - A Good Alternative in the Acute Treatment of Trigeminal Neuralgia]

Brivaracetam - A Good Alternative in the Acute Treatment of Trigeminal Neuralgia Abstract. In trigeminal neuralgia there is brief neuropathic pain in the supply area of the trigeminal nerve. A distinction is made between classic, symptomatic, and idiopathic trigeminal neuralgia. Only a few drugs are available for acute treatment. In the presented case series, we report on five patients with trigeminal neuralgia of various origins who responded well to treatment with brivaracetam. Brivaracetam binds to the synaptic vesicle protein 2A, which is also found on nerves and nerve roots. SV2 regulates the exocytotic release of neurotransmitters, which may explain the effect of brivaracetam on neuropathic pain. The use of brivaracetam can be helpful in the short-term therapy of paroxysmal pain with trigeminal neuralgia. Further studies are required to demonstrate this effect and to rule out a placebo effect.

Effectiveness of nonsurgical treatments for trigeminal neuralgia: an overview protocol

ABSTRACT Purpose: to present an overview protocol for systematic reviews to synthesize and describe available evidence on the effectiveness of nonsurgical treatments for trigeminal neuralgia. Methods: the protocol follows the method proposed by PRISMA-P guidelines for protocol reports. The search will be made in MEDLINE, EMBASE, LILACS, Cochrane, Web of Science, Scopus, SpeechBITE, PeDRO, and the grey literature (Google Scholar and ProQuest Dissertations and Theses), with no restriction on language or time of publication. A search strategy developed for MEDLINE will be adapted for each database. Two independent reviewers will screen the articles by title and abstract. Then, they will read the full texts of included articles, following the eligibility criteria. In case of disagreements, a third reviewer will come to a consensus. The data will be extracted with a standardized form. Information on the risk of bias and GRADE assessment will be recorded. AMSTAR-2 will assess the overall result reliability of the systematic reviews. Results will be presented in a flowchart, tables, and a narrative description. Final Considerations: once carried out, this protocol will describe the current body of research on the topic and identify existing gaps on the basis of evidence.

Macrovascular decompression of a dolichoectatic vertebral artery via Kawase approach in a patient suffering from trigeminal neuralgia – A case report

Introduction

Secondary trigeminal neuralgia due to vertebrobasilar dolichoectasia is a rare entity. Surgical therapy via pterional craniotomy approach and anterior petrosectomy has already been described in literature. We present an 81-year female patient suffering from left sided trigeminal neuralgia due to vertebrobasilar dolichoectasia.

Research question

We show in this case report a macrovascular decompression of a dolichoectatic vertebral artery via Kawase approach.

Material and methods

Successful decompression under continuous intraoperative neuromonitoring via pure Kawase approach and ventro-lateral transposition of a dolichoectatic vertebral artery through a polyester-titanium sling was achieved.

Results

Postoperative the patient described an immediate improvement of the trigeminal neuralgia symptoms. At the two-month postoperative follow-up the patient remained trigeminal neuralgia painless free and suffered from a regredient facial nerve palsy.

Discussion and conclusion

We report for the first time a successful macrovascular decompression of a dolichoectatic vertebral artery via Kawase approach under continuous intraoperative neuromonitoring. In-contrast to traditional suboccipital retrosigmoidal approach our strategy obtains sufficient working space and angles. Thus, adequate transposition of the dolichoectatic vessel could be achieved.

•

Secondary trigeminal neuralgia due to vertebrobasilar dolichoectasia is a rare entity.

•

Successful macrovascular decompression of a dolichoectatic vertebral artery via Kawase approach.

•

Transposition through a polyester-titanium sling.

A efetividade dos tratamentos não cirúrgicos na neuralgia do trigêmeo: um protocolo de overview

RESUMO Objetivo: apresentar um protocolo de Overview das revisões sistemáticas (RSs) para sintetizar e descrever evidências disponíveis sobre a efetividade dos tratamentos não cirúrgicos na neuralgia do trigêmeo. Métodos: o protocolo seguirá o método proposto pelas diretrizes do PRISMA-P para relato de protocolos. A busca será realizada nas bases de dados eletrônicas: MEDLINE, EMBASE, Lilacs, COCHRANE, Web of Science, Scopus, SpeechBITE, PeDRO, além de consulta à literatura cinzenta (Google Scholar e ProQuest Dissertations and Theses), sem restrições de idioma ou período de publicação. Uma estratégia de busca foi desenvolvida para MEDLINE e será adaptada para cada base de dados. O rastreio dos artigos pelo título e resumo será realizado por dois revisores independentes. Em seguida, farão leitura dos textos completos dos artigos incluídos, conforme os critérios de elegibilidade. Em discordância, um terceiro revisor fará o consenso. Os dados serão extraídos por meio de um formulário padronizado. Serão registradas informações de risco de viés e avaliação do GRADE. A ferramenta AMSTAR II avaliará a confiança geral dos resultados das RSs. Os resultados serão apresentados em um fluxograma, tabelas e descrição narrativa. Considerações Finais: a execução deste protocolo descreverá o corpo atual de pesquisa sobre o tema e identificará lacunas existentes na base de evidências.

Familial occurrence of classical and idiopathic trigeminal neuralgia

Trigeminal neuralgia (TN) is a severe facial pain disease with unknown pathogenesis. It has been thought that the familial form of TN is rare with a prevalence of about 1-2% among affected individuals, but emerging evidence suggests a role of genetic factors. This study examined the occurrence of familial TN among patients with classical or idiopathic TN. Patients with TN recruited from a hospital registry received an informed consent form with a questionnaire, and individuals reporting other family members with TN underwent a structured phone-interview. For affected family members, type of TN, available clinical, imaging, management results and available hospital patient records were studied. Pedigrees for all affected families were established. This study included 268 patients with either classical or idiopathic TN. The familial form of TN was present in 41/268 (15.3%) patients, that is, 37/244 (15.2%) patients with classical TN and in 4/24 (16.7%) with idiopathic TN. Total 38 families were identified, with two affected members in 32/38 families (84.2%), three affected family members in 5/38 (13.2%) and four family members in 1/38 (2.6%) families. Comparing the 41 familial TN cases with the 227 sporadic TN patients showed significantly earlier onset of TN and a significantly higher occurrence of right-sided pain in familial cases, while there was no difference in gender distribution, occurrence of arterial hypertension or trigeminal branch involved. Among patients with classical or idiopathic TN, the occurrence of the familial form of the disease is more frequent than traditionally assumed.

Intravenous fosphenytoin therapy for rescue of acute trigeminal neuralgia crisis in patients awaiting neurosurgical procedures: A cross-sectional study

Few treatments exist for acute attacks of trigeminal neuralgia. Therefore, this study aimed to investigate the efficacy and safety of an intravenous fosphenytoin therapy protocol in a trigeminal neuralgia crisis. We conducted a single-center, retrospective, observational study of the records of 20 patients with trigeminal neuralgia who received intravenous fosphenytoin therapy (15 mg/mL in normal saline at 50 mg/min for 15 min, total 750 mg) during hospitalization between September 2015 and August 2020. Serum phenytoin concentration was measured 30 min post-infusion. Pain severity was evaluated using a numerical rating scale and was analyzed for statistical significance. The mean age of the patients was 67.5 years (female, 50.0%). The median numerical rating scale score (interquartile range) of pain severity was 2.35 (0-10), 0.65 (0-5), 0.15 (0-1), 2.00 (0-8), and 4.30 (0-10) at 15, 30, and 60 min, and 12 and 24 h, respectively (p < .001); the numerical rating scale score was 10 before treatment. Reduction in pain 24 h following treatment was significant. The mean phenytoin concentration was 12.8 μg/mL 30 min post-treatment. While mild dizziness occurred in four patients, all could walk independently within 60 min. The mean age and weight of patients with mild dizziness were significantly higher and lower, respectively (p < .001), than those of other patients. These results may provide physicians with new insights into the innovative therapeutic option of intravenous fosphenytoin and contribute to advancements in treating acute trigeminal neuralgia crisis.

Microvascular decompression in trigeminal neuralgia: predictors of pain relief, complication avoidance, and lessons learned

OBJECTIVE

To analyze characteristics associated with long-term pain relief after microvascular decompression (MVD) for trigeminal neuralgia (TGN). Description of associated morbidity and complication avoidance.

METHODS

One hundred sixty-five patients with TGN underwent 171 MVD surgeries at the authors' institution. Patient characteristics and magnetic resonance imaging (MRI) datasets were obtained through the hospital's archiving system. Patients provided information about pre- and post-operative pain characteristics and neurologic outcome. Favorable outcome was defined as a Barrow Neurological Institute (BNI) pain intensity score of I to III with post-operative improvement of I grade.

RESULTS

Type of TGN pain with purely paroxysmal pain (p = 0.0202*) and TGN classification with classical TGN (p = 0.0372*) were the only significant predictors for long-term pain relief. Immediate pain relief occurred in 90.6% of patients with a recurrence rate of 39.4% after 3.5 ± 4.6 years. MRI reporting of a neurovascular conflict had a low negative predictive value of 39.6%. Mortality was 0% with major complications observed in 8.2% of patients. Older age was associated with lower complication rates (p = 0.0009***). Re-MVD surgeries showed improved long-term pain relief in four out of five cases.

CONCLUSIONS

MVD is a safe and effective procedure even in the elderly. It has the unique potential to cure TGN if performed on a regular basis, and if key surgical steps are respected. Early MVD should be offered in case of medical treatment failure and paroxysmal pain symptoms. The presence of a neurovascular conflict on MRI is not mandatory. In case of recurrence, re-MVD is a good treatment option that should be discussed with patients.

HIGHLIGHTS

• Long-term analysis of pain relief after MVD. • Positive predictors for outcome: classical TGN and purely paroxysmal pain. • Presence of neurovascular conflict in MRI is not mandatory for MVD surgery. • Analysis of complications and surgical nuances for avoidance. • MVD is a safe procedure also in the elderly.

Results of three or more Gamma Knife radiosurgery procedures for recurrent trigeminal neuralgia

OBJECTIVE

Gamma Knife radiosurgery (GKRS) is an established surgical option for the treatment of trigeminal neuralgia (TN), particularly for high-risk surgical candidates and those with recurrent pain. However, outcomes after three or more GKRS treatments have rarely been reported. Herein, the authors reviewed outcomes among patients who had undergone three or more GKRS procedures for recurrent TN.

METHODS

The authors conducted a multicenter retrospective analysis of patients who had undergone at least three GKRS treatments for TN between July 1997 and April 2019 at two different institutions. Clinical characteristics, radiosurgical dosimetry and technique, pain outcomes, and complications were reviewed. Pain outcomes were scored on the Barrow Neurological Institute (BNI) scale, including time to pain relief (BNI score ≤ III) and recurrence (BNI score > III).

RESULTS

A total of 30 patients were identified, including 16 women and 14 men. Median pain duration prior to the first GKRS treatment was 10 years. Three patients (10%) had multiple sclerosis. Time to pain relief was longer after the third treatment (p = 0.0003), whereas time to pain recurrence was similar across each of the successive treatments (p = 0.842). Complete or partial pain relief was achieved in 93.1% of patients after the third treatment. The maximum pain relief achieved after the third treatment was significantly better among patients with no prior percutaneous procedures (p = 0.0111) and patients with shorter durations of pain before initiation of GKRS therapy (p = 0.0449). New or progressive facial sensory dysfunction occurred in 29% of patients after the third GKRS treatment and was reported as bothersome in 14%. One patient developed facial twitching, while another experienced persistent lacrimation. No statistically significant predictors of adverse effects following the third treatment were found. Over a median of 39 months of follow-up, 77% of patients maintained complete or partial pain relief. Three patients underwent a fourth GKRS treatment, including one who ultimately received five treatments; all of them reported sustained pain relief at the extended follow-up.

CONCLUSIONS

The authors describe the largest series to date of patients undergoing three or more GKRS treatments for refractory TN. A third treatment may produce outcomes similar to those of the first two treatments in terms of long-term pain relief, recurrence, and adverse effects.

Pharmacologic Management of Neuropathic Pain

This article aims to provide the practitioner with therapeutic options to treat a broad spectrum of acute and chronic orofacial pain syndromes. The focus will be nonsurgical that the oral health care physician can implement to treat this population of patients. The World Health Organization estimated that more than 1 in every 3 people suffers from acute or chronic pain. This article is primarily devoted to medication management once the diagnosis of neuropathic pain, a true trigeminal neuralgia, or a variant of trigeminal neuralgia often referred to as traumatic neuropathic pain or traumatic trigeminal neuralgia.

Trigeminal Neuralgia: Current Approaches and Emerging Interventions

Trigeminal neuralgia (TN) has been described in the literature as one of the most debilitating presentations of orofacial pain. This review summarizes over 150 years of collective clinical experience in the medical and surgical treatment of TN. Fundamentally, TN remains a clinical diagnosis that must be distinguished from other types of trigeminal neuropathic pain and/or facial pain associated with other neuralgias or headache syndromes. What is increasingly clear is that there is no catch-all medical or surgical intervention that is effective for all patients with trigeminal neuralgia, likely reflective of the fact that TN is likely a heterogenous group of disorders that jointly manifests in facial pain. The first-line treatment for TN remains anticonvulsant medical therapy. Patients who fail this have a range of surgical options available to them. In general, microvascular decompression is a safe and effective procedure with immediate and durable outcomes. Patients who are unable to tolerate general anesthesia or whose medical comorbidities preclude a suboccipital craniectomy may benefit from percutaneous methodologies including glycerol or radiofrequency ablation, or both. For patients with bleeding diathesis due to blood thinning medications who are ineligible for invasive procedures, or for those who are unwilling to undergo open surgical procedures, radiosurgery may be an excellent option-provided the patient understands that maximum pain relief will take on the order of months to achieve. Finally, peripheral neurectomies continue to provide an inexpensive and resource-sparing alternative to pain relief for patients in locations with limited economic and medical resources. Ultimately, elucidation of the molecular mechanisms underlying trigeminal neuralgia will pave the way for novel, more effective and less invasive therapies.

Modulation of excitatory synaptic transmissions by TRPV1 in the spinal trigeminal subnucleus caudalis neurons of neuropathic pain rats

The present study examined contribution of the transient receptor potential vanilloid 1 channel (TRPV1) to the chronic orofacial pain. Bilateral partial nerve ligation (PNL) of the mental nerve, a branch of trigeminal nerve, was performed to induce neuropathic pain. The withdrawal threshold in response to mechanical stimulation of the lower lip skin was substantially reduced after the surgery in the PNL rats while it remained unchanged in the sham rats. This reduction in the PNL rats was alleviated by pregabalin injected intraperitoneally (10 mg/kg) and intracisternally (10, 30, 100 μg). Furthermore, an intracisternal injection of AMG9810, an antagonist of TRPV1, (1.5, 5.0 μg) attenuated the reduction of withdrawal threshold. Spontaneous and miniature excitatory postsynaptic currents (sEPSCs and mEPSCs) were recorded from the spinal trigeminal subnucleus caudalis (Vc) neurons in the brainstem slice, which receive the orofacial nociceptive signals. In the PNL rats, superfusion of capsaicin (0.03, 0.1 μM) enhanced their frequency without effect on the amplitude and the highest concentration (0.3 μM) increased both the frequency and amplitude. In the sham rats, only 0.3 μM capsaicin increased their frequency. Thus, capsaicin-induced facilitation of sEPSCs and mEPSCs in the PNL rats was significantly stronger than that in the sham rats. AMG9810 (0.1 μM) attenuated the capsaicin's effect. Capsaicin was ineffective on the trigeminal tract-evoked EPSCs in the PNL and sham rats. These results suggest that the chronic orofacial pain in the PNL model results from facilitation of the spontaneous excitatory synaptic transmission in the Vc region through TRPV1 at least partly.

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.

Exploring patient satisfaction of a joint-consultation clinic for trigeminal neuralgia: Enabling improved decision-making

Background

Trigeminal neuralgia (TN) is a relatively rare condition which has a profound impact not only on the patient but also on those around them. There is no cure for TN, and the management of the condition is complex. The most effective forms of treatment are either through medication, neurosurgery, or combination of the two. Each option has risks and implications for the patient. As with all clinical decisions, it is important for patients to understand and be fully informed of the treatments available to them. A London UK unit adopted a joint-consultation clinic approach where the patient meets with both physician and neurosurgeon at the same time to discuss treatment options. The purpose of this evaluation is to understand patients’ level of satisfaction with the joint-consultation clinic and evaluate utilisation of a clinical decision-making tool.

Method

Patients who had attended the joint-consultation clinic over a period of 12 months were invited to participate in a telephone or paper survey (N = 55). Responses were analysed using descriptive statistics and thematic analysis.

Results

Forty-one patients (77% response rate) participated in the survey, and the results were overwhelmingly positive for the joint-consultation clinic regarding satisfaction. The benefits were broad ranging including increased understanding, collaboration and confidence in decision-making.

Conclusions

A joint-consultation clinic comprising a neurosurgeon and a physician for the treatment of TN is valued by patients who become better informed and able to make decisions about their care. Positive application of clinical decision-making aids in this situation offers potential across specialities.

Recurrence Rates After Microvascular Decompression in Patients With Primary Trigeminal Neuralgia and Its Influencing Factors: A Systematic Review and Meta-Analysis Based on 8,172 Surgery Patients

Background: Primary trigeminal neuralgia (PTN) is known to reoccur following microvascular decompression (MVD) surgery. However, the rates and contributing factors related to PTN recurrence remain controversial. The purpose of this study was to explore the postoperative recurrence rates and related influencing factors of patients with PTN after MVD. Additionally, recurrence rates after different treatments were compared to provide guidelines for clinicians. Methods: We conducted systematic reviews and meta-analyses in accordance with the preferred reporting items of the PRISMA guidelines. We searched nine databases, namely, the PubMed, EMBASE, Cochrane Library, Web of Science, CINAHL, CBM, CNKI, VIP, and Wanfang databases, from establishment to July 13, 2020, selecting for studies about the long-term postoperative efficacy of MVD in the treatment of PTN. Factors associated with higher recurrence rates after MVD and long-term postoperative results of other treatments underwent formal meta-analysis, where odds ratios (ORs) with the corresponding 95% confidence intervals (CIs) were calculated. The dose-response model was used to inspect the associations between several factors and higher recurrence rates. Results: Seventy-four studies (8,172 patients, 32 case series studies, and 42 non-randomized controlled trials) were analyzed in our research. Overall, 956 out of 8,172 patients relapsed, and the pooled recurrence rate was 0.096 (0.080-0.113). Influencing factors of relatively higher recurrence rates included atypical trigeminal neuralgia symptoms, lack of nerve groove, non-arterial compression, patients who were 50-60 years old, and longer disease duration. Dose-response analysis showed that the recurrence rate had a significant trend with the published year and the follow-up time. Simultaneously, the recurrence rate of MVD treatment was much lower than that of conventional drug treatment, gamma knife surgery, percutaneous balloon compression, and radiofrequency thermocoagulation. When the surgical technique was improved or combined with partial sensory rhizotomy (PSR), the postoperative recurrence rates were significantly reduced. Conclusions: Even for PTN patients who have a successful operation, ~10% of them will still relapse. This research identifies several factors that can affect the recurrence rate. Compared with other operations, MVD has a relatively lower recurrence rate. Our analysis suggests that improved surgical techniques and combining PSR and MVD will yield better results. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42020159276.

Characteristics and natural disease history of persistent idiopathic facial pain, trigeminal neuralgia, and neuropathic facial pain

OBJECTIVE

This study aimed to characterize key features, and to assess the clinical development of common nondental facial pain syndromes such as persistent idiopathic facial pain (PIFP), trigeminal neuralgia (TN), and neuropathic facial pain (NEUROP).

METHODS

This is a longitudinal study in which prospective questionnaire data of patients presenting to a specialized outpatient clinic were collected from 2009 to 2019. A telephone interview was conducted with the same patients in 2020 to assess the natural disease history.

RESULTS

n = 411 data sets of patients with chronic facial pain were compiled. Among these were n = 150 patients with PIFP, n = 111 patients with TN, and n = 86 patients with NEUROP. Guideline therapy had not been initiated in 38.7% (58/150; PIFP), 19.8% (22/111; TN), and 33.7% (29/86; NEUROP) patients. Of the patients with PIFP, 99.3% (149/150) had primarily consulted a dentist due to their pain syndrome. The additional telephone interview was completed by 236 out of the 411 patients (57.4%). Dental interventions in healthy teeth had been performed with the intention to treat the pain in many patients (78/94 [83.0%] PIFP; 34/62 [54.8%] TN; 19/43 [44.2%] NEUROP), including dental extractions. 11.3% (7/43) of the patients with TN had never profited from any therapy. In contrast, 29.8% (28/94) of the patients with PIFP had never profited from any therapy. Furthermore, the primary pharmaceutical therapy options suggested by national guidelines were, depending on the substance class, only considered to be effective by 13.8% (13/94; antidepressants) and 14.9% (14/94; anticonvulsants) of the patients with PIFP.

CONCLUSIONS

Facial pain syndromes pose a considerable disease burden. Although treatment of TN seems to be effective in most patients, patients with PIFP and NEUROP report poor effectiveness even when following guideline therapy suggestions. In addition, unwarranted dental interventions are common in facial pain syndromes.

Systemic and intrathecal baclofen produce bladder antinociception in rats

BACKGROUND

Baclofen, a clinically available GABAB receptor agonist, produces non-opioid analgesia in multiple models of pain but has not been tested for effects on bladder nociception.

METHODS

A series of experiments examined the effects of systemic and spinally administered baclofen on bladder nociception in female anesthetized rats. Models of bladder nociception included those which employed neonatal and adult bladder inflammation to produce bladder hypersensitivity.

RESULTS

Cumulative intraperitoneal dosing (1-8 mg/kg IP) and cumulative intrathecal dosing (10-160 ng IT) of baclofen led to dose-dependent inhibition of visceromotor responses (VMRs) to urinary bladder distension (UBD) in all tested models. There were no differences in the magnitude of the analgesic effects of baclofen as a function of inflammation versus no inflammation treatments. Hemodynamic (pressor) responses to UBD were similarly inhibited by IT baclofen as well as UBD-evoked excitatory responses of spinal dorsal horn neurons. The GABAB receptor antagonist, CGP 35,348, antagonized the antinociceptive effects of IT baclofen on VMRs in all tested models but did not affect the magnitude of the VMRs by itself suggesting no tonic GABAB activity was present in this preparation. Tolerance to a seven day continuous IT infusion of baclofen was not observed.

CONCLUSIONS

These data provide support for a clinical trial of baclofen as a non-opioid treatment of human bladder pain.

Trigeminal neuralgia: a practical guide

Trigeminal neuralgia (TN) is a highly disabling disorder characterised by very severe, brief and electric shock like recurrent episodes of facial pain. New diagnostic criteria, which subclassify TN on the basis of presence of trigeminal neurovascular conflict or an underlying neurological disorder, should be used as they allow better characterisation of patients and help in decision-making regarding medical and surgical treatments. MR imaging, including high-resolution trigeminal sequences, should be performed as part of the diagnostic work-up. Carbamazepine and oxcarbazepine are drugs of first choice. Lamotrigine, gabapentin, pregabalin, botulinum toxin type A and baclofen can be used either alone or as add-on therapy. Surgery should be considered if the pain is poorly controlled or the medical treatments are poorly tolerated. Trigeminal microvascular decompression is the first-line surgery in patients with trigeminal neurovascular conflict while neuroablative surgical treatments can be offered if MR imaging does not show any neurovascular contact or where patients are considered too frail for microvascular decompression or do not wish to take the risk.

Efficacy of Erenumab in the Treatment of Trigeminal Neuralgia: A Retrospective Case Series

Objective

Trigeminal neuralgia (TN) is a chronic, often refractory, pain condition, which adversely affects the lives of patients. Current treatments are only mildly effective. Anti-calcitonin gene-related peptide (CGRP) monoclonal antibodies have been successfully studied in the treatment of migraines. CGRP plays a role in both TN and migraine. It is prudent to attempt CGRP monoclonal antibody therapy in TN. Erenumab, a human anti-CGRP monoclonal antibody medication, modulates CGRP, which is elevated in patients with TN. The primary objective of this study was to evaluate the efficacy of erenumab for patients with TN.

Methods

Retrospective analysis was performed on data collected from 10 patients diagnosed with TN and treated with erenumab for 6 months. Pain was tracked using a numeric pain rating scale (NPRS) from 0 to 10. The effect of erenumab on NPRS after 6 months' time was the primary end point. Secondary end points included side effects to therapy, improvement in headache frequency in those with comorbid migraine, evaluating mood following therapy, and global mood improvement using scale (worse, no change, improved).

Results

Nine of 10 patients (90.0%) reported improvement in pain severity and in global mood improvement. Three patients reported resolution of anxiety and/or depression. Side effects were minimal, with 3 patients reporting constipation, injection site reactions, or both.

Conclusions

Based on these results, erenumab appears to be an efficacious treatment option for patients with refractory TN. Patients experienced improvement in pain, reduced frequency of headache, and improvement in mood. Treatment was well tolerated with only mild side effects reported.

Classification of Evidence

This study provides Class IV evidence that erenumab increases the probability of improved pain control in patients with medication-resistant TN.

Flatness of the Meckel cave may cause primary trigeminal neuralgia: a radiomics-based study

Background

Neurovascular contact (NVC) is the main cause of primary trigeminal neuralgia (PTN); however, cases of PTN without NVC are still observed. In this study, the Meckel cave (MC) morphology in PTN were analyzed by radiomics and compared to healthy controls (HCs) to explore the cause of PTN.

Methods

We studied the 3.0T MRI data of 115 patients with PTN and 46 HCs. Bilateral MC was modeled using the 3D Slicer software, and the morphological characteristics of MC were analyzed using the radiomics method.

Results

The right side incidence rate in the PTN group was higher than the left side incidence. By analyzing the flatness feature of MC, we observed that the affected side of the PTN was lower than that of the unaffected side, the right MC of the PTN and HC was lower than that of the left MC, the MC of the affected side of the left and right PTN without bilateral NVC was lower than that of the unaffected side.

Conclusions

By providing a method to analyze the morphology of the MC, we found that there is an asymmetry in the morphology of bilateral MC in the PTN and HC groups. It can be inferred that the flatness of the MC may be a cause of PTN.

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.

Beyond chronic migraine: a systematic review and expert opinion on the off-label use of botulinum neurotoxin type-A in other primary headache disorders

Introduction: Botulinum neurotoxin type-A (BoNTA) is licensed for the treatment of chronic migraine (CM), but it has been tested off-label as a therapeutic choice in other primary headaches (PHs). We aimed to provide a systematic review and expert opinion on BoNTA use in PHs, beyond CM.Areas covered: After providing an overview on PHs and mechanism of BoNTA action, we report the results of a systematic review, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations, of BoNTA therapeutic trials in PHs beyond CM. Studies and results were reviewed and discussed, and levels of evidence were graded. We also collected data on relevant ongoing trials.Expert opinion: Although there are contradictory findings on PHs other than CM, BoNTA may represent a therapeutic option for patients who do not respond to conventional prophylactic treatments. Based on limited available evidence, BoNTA may be considered in refractory tension-type headache, trigeminal autonomic cephalalgias, primary stabbing headache, nummular headache, hypnic headache, and new daily persistent headache, after the primary nature of cephalalgia has been documented and other drugs have failed. Experienced physicians in BoNTA treatment are required to guide the therapeutic protocol for each patient to optimize good and safe outcomes.