Crisugabalin, a ligand for the α2δ subunit of voltage-gated calcium channels, exhibits no obvious abuse potential in rodents

Crisugabalin, a novel third-generation ligand targeting the α2δ subunit of voltage-gated calcium channels, has been approved in China for the treatment of pain associated with diabetic peripheral neuropathy and postherpetic neuralgia. Existing research suggests that ligands for the α2δ subunit of voltage-gated calcium channels may carry a risk of abuse. To evaluate the abuse potential of crisugabalin, five well-recognized animal models were utilized in these preclinical studies. Firstly, an intravenous self-administration paradigm was implemented in rats that were self-administering propofol to assess the reinforcing effects of crisugabalin. Secondly, a rat drug discrimination study was employed to determine the pharmacological similarity between crisugabalin and the training drug midazolam. Then, a conditioned place preference (CPP) paradigm in rats was utilized to evaluate the rewarding properties of crisugabalin. After that, a spontaneous withdrawal study was conducted in rats chronically treated with crisugabalin to examine the liability of developing physical dependence. Finally, a mouse pentylenetetrazol-induced convulsion model was used following chronic exposure to crisugabalin to assess its potential for physical dependence. The results indicated that crisugabalin showed no positive reinforcing effects and did not display midazolam-like discriminative stimulus effects. Moreover, crisugabalin did not induce significant CPP in rats and there was no risk of physical dependence in the pentylenetetrazol-induced convulsion model. In the rat spontaneous withdrawal study, crisugabalin demonstrated a very low level of physical dependence. These findings suggest that crisugabalin has minimal to no potential for abuse, thereby establishing itself as a safer option relative to pregabalin and mirogabalin.

13. Trigeminal Neuralgia

INTRODUCTION

Trigeminal neuralgia (TN) is a disorder characterized by recurrent, unilateral brief electric shock-like pains, abrupt in onset and termination, limited to the distribution of one or more branches of the trigeminal nerve, and triggered by innocuous stimuli.

METHODS

The literature on the diagnosis and treatment of TN was retrieved and summarized.

RESULTS

The diagnosis is made almost entirely based on the patient's history. In classical TN, the neurological examination is typically normal, whereas the exam in secondary TN is focused on surveilling for signs of multiple sclerosis (MS) or a cerebellopontine tumor. The appropriate imaging technique is magnetic resonance imaging (MRI) with contrast of the trigeminal ganglion, which is recommended prior to interventional procedures. The treatment of a patient with TN is a team effort and should always be multidisciplinary, addressing all dimensions of pain. Carbamazepine or oxcarbazepine are first-line medical treatments. Microvascular decompression (MVD) is the technique of choice for patients without or with minor comorbidities. Percutaneous procedures for TN are mainly radiofrequency thermocoagulation of the branches of the trigeminal nerve introduced by Sweet and Wepsic in 1965, retrogasserian glycerol injection introduced by Hakanson in 1981, and balloon compression introduced by Mullan and Lichtor in 1983. Radiofrequency treatment is recommended in elderly patients or those with major comorbidities. Other techniques such as stereotactic radiosurgery and pulsed radiofrequency treatment are also discussed.

CONCLUSIONS

Recommendations are based on very low-quality evidence. MVD and radiofrequency are the preferred invasive treatments, although higher-quality evidence is necessary to better assess the risk-benefit ratios.

Second-line pharmacological treatment strategies for trigeminal neuralgia: A retrospective comparison of lacosamide, gabapentin and baclofen

BACKGROUND AND OBJECTIVES

Carbamazepine is commonly used as the first-line treatment for trigeminal neuralgia, but therapeutic failure due to adverse effects is frequent. While various second-line alternatives have been suggested, there is limited evidence directly comparing these options. This study aimed to evaluate and compare the effectiveness and tolerability of lacosamide, gabapentin, and baclofen in patients with refractory trigeminal neuralgia.

METHODS

This retrospective cohort study analyzed patients with trigeminal neuralgia who, after not responding to carbamazepine, were treated with either lacosamide, gabapentin, or baclofen between January 2015 and December 2023. We collected clinical and demographic data and assessed response variables after 3 months of treatment. We compared pain relief (defined as patient-reported pain reduction and absence of additional treatments or emergency consultations within 3 months) and side effects. Secondary endpoints included absence of pain, treatment retention rates, and the need for subsequent surgery.

RESULTS

A total of 49 patients were included, with 22 receiving lacosamide, 13 receiving gabapentin, and 14 receiving baclofen. The mean (standard deviation) age was 62.1 (14.1) years, with 53% female, and the median duration since diagnosis was 3.4 years. Carbamazepine failure was attributed to inefficacy in 76% of patients and intolerance in 24%. There were no significant demographic or clinical differences among the treatment groups, except for the concurrent use of carbamazepine: 68% in the lacosamide group, 54% in the gabapentin group, and 100% in the baclofen group (p = 0.019). Pain relief rates were 68% for lacosamide, 54% for gabapentin, and 64% for baclofen (p = 0.694). Adverse effects were reported in 46% of lacosamide, 31% of gabapentin, and 36% of baclofen users (p = 0.664). Complete pain relief was achieved in 36% with lacosamide, 53% with gabapentin, and 21% with baclofen (p = 0.218). The treatment discontinuation rates due to intolerance were 23% for lacosamide, 31% for gabapentin, and 21% for baclofen (p = 0.825).

CONCLUSION

Lacosamide may be a viable second-line treatment option for refractory trigeminal neuralgia, showing comparable outcomes to gabapentin and baclofen.

Outcomes and safety of repeated microvascular decompression for recurrent trigeminal neuralgia

OBJECTIVE

Recurrent Trigeminal Neuralgia (TN) poses significant challenges for treatment, often necessitating repeated Microvascular Decompression (MVD). This study aims to evaluate the safety, efficacy, and prognostic factors associated with repeated MVD for recurrent TN at our institution. A retrospective review was conducted on 147 patients who underwent repeated MVD between September 2010 and September 2023. Data on surgical procedures, postoperative outcomes, and recurrence rates were collected. The primary endpoint was recurrent pain. Univariate and multivariate Cox proportional hazards analyses were used to identify predictors of pain recurrence. In this cohort, 147 patients underwent revision surgery, comprising 97 females and 50 males. The primary reason for the nonresolution in 96 patients was adhesions of Teflon pledgets to the trigeminal nerve, while in 51 patients, previously missed vascular compression was identified. After a median follow-up of 53.3 months, 14 patients were lost to follow-up. Twelve patients (9.0%) reported no pain relief after repeated MVD, while 121 patients (91.0%) achieved complete pain relief. The most common complication was facial numbness, occurring in 101 cases (68.7%), followed by blurred vision (11 patients, 7.5%), hearing impairment (8 patients, 5.4%), poor wound healing (2 patients, 1.4%), postoperative stroke confirmed by CT imaging (2 patients, 1.4%) and permanent ataxia (2 patients, 1.4%). The mortality rate for repeated MVD at our center was zero. Twenty-four patients (19.8%) experienced pain recurrence, with a median pain-free survival (PFS) of 36.0 months. The 5- and 10-year PFS rates were 80.8% and 54.5%, respectively. Patients who underwent combined partial sensory rhizotomy (PSR) and MVD (Hazard Ratio [HR] 0.203, 95% Confidence Interval [CI] 0.047-0.882, p = 0.033) or circumferential dissection and MVD (HR 0.295, 95% CI 0.099-0.882, p = 0.029) had lower recurrence rates compared to MVD alone. Long-term facial numbness was the most common complication, particularly in patients undergoing PSR. Repeated MVD is effective and safe for recurrent TN. PSR with MVD is associated with lower rate of TN recurrence but increases the risk of facial numbness. Conversely, circumferential dissection is associated with lower recurrence rates without increasing postoperative facial numbness.

CLINICAL TRIAL NUMBER

Not applicable.

A Comparison of Radiosurgical Planning Techniques for the Treatment of Trigeminal Neuralgia

PURPOSE

To survey and analyze the current peer-reviewed literature on physical aspects of radiosurgical treatment of trigeminal neuralgia (TN), and objectively determine the comparative differences between common treatment planning techniques/modalities when variability in computed tomography and magnetic resonance imaging data sets and clinical approaches are minimized.

METHODS AND MATERIALS

Example treatment plans were created from 8 distinct planning approaches on a unique computed tomography and magnetic resonance imaging data set. Treatment plan selection comprised Gamma Knife, physical cone, and multileaf collimator-based plans. The prescription was standardized between plans to 85 Gy at the isocenter, as well as the location of the treatment isocenter. Dose distributions were characterized using multiplanar isodose line comparisons, dose line profiles in 2 dimensions, gradient indices, dimensional and volumetric analysis of 50% and 80% isodose coverage, and maximum (0.1 cc) dose to the brainstem as singularly contoured on the unique imaging data set.

RESULTS

Dose coverage, distribution shape, dose line profiles, and gradients differ significantly between Gamma Knife, physical cone, and multileaf collimator-based planning techniques, even when dose prescription, treatment isocenter, and imaging data set/anatomy are identical between treatment plans. Gamma Knife (4 mm collimator) provides the broadest coverage of the trigeminal nerve, most closely approximated by the 5 mm physical cone linear accelerator (LINAC)-based plan. Contrastingly, the smallest cross-sectional coverage in this treatment plan selection was created by the 4 mm LINAC physical cone. All dose distributions were approximately spherical except the 11-arc physical cone LINAC-based plan, which produces a more elongated distribution (broadest adjacent to the brainstem).

CONCLUSIONS

The selection of a radiosurgical technique for TN should be weighed in the context of differences in dose distributions between treatment techniques, as demonstrated by the plans analyzed in this study. It cannot be assumed that all TN radiosurgical techniques produce the same dose distribution, either to the trigeminal nerve or adjacent normal tissues. Differences between planning techniques may be amplified in real clinical scenarios with differences in clinical approach and anatomy.

Pharmacotherapy and non-invasive neuromodulation for neuropathic pain: a systematic review and meta-analysis

BACKGROUND

There remains a substantial unmet need for effective and safe treatments for neuropathic pain. The Neuropathic Pain Special Interest Group aimed to update treatment recommendations, published in 2015, on the basis of new evidence from randomised controlled trials, emerging neuromodulation techniques, and advances in evidence synthesis.

METHODS

For this systematic review and meta-analysis, we searched Embase, PubMed, the International Clinical Trials Registry, and ClinicalTrials.gov from data inception for neuromodulation trials and from Jan 1, 2013, for pharmacological interventions until Feb 12, 2024. We included double-blind, randomised, placebo-controlled trials that evaluated pharmacological and neuromodulation treatments administered for at least 3 weeks, or if there was at least 3 weeks of follow-up, and which included at least ten participants per group. Trials included participants of any age with neuropathic pain, defined by the International Association for the Study of Pain. We excluded trials with enriched enrolment randomised withdrawal designs and those with participants with mixed aetiologies (ie, neuropathic and non-neuropathic pain) and conditions such as complex regional pain syndrome, low back pain without radicular pain, fibromyalgia, and idiopathic orofacial pain. We extracted summary data in duplicate from published reports, with discrepancies reconciled by a third independent reviewer on the platform Covidence. The primary efficacy outcome was the proportion of responders (50% or 30% reduction in baseline pain intensity or moderate pain relief). The primary safety outcome was the number of participants who withdrew from the treatment owing to adverse events. We calculated a risk difference for each comparison and did a random-effects meta-analysis. Risk differences were used to calculate the number needed to treat (NNT) and the number needed to harm (NNH) for each treatment. Risk of bias was assessed by use of the Cochrane risk of bias tool 2 and certainty of evidence assessed by use of GRADE. Recommendations were based on evidence of efficacy, adverse events, accessibility, and cost, and feedback from engaged lived experience partners. This study is registered on PROSPERO, CRD42023389375.

FINDINGS

We identified 313 trials (284 pharmacological and 29 neuromodulation studies) for inclusion in the meta-analysis. Across all studies, 48 789 adult participants were randomly assigned to trial groups (20 611 female and 25 078 male participants, where sex was reported). Estimates for the primary efficacy and safety outcomes were tricyclic antidepressants (TCAs) NNT=4·6 (95% CI 3·2-7·7), NNH=17·1 (11·4-33·6; moderate certainty of evidence), α2δ-ligands NNT=8·9 (7·4-11·10), NNH=26·2 (20·4-36·5; moderate certainty of evidence), serotonin and norepinephrine reuptake inhibitors (SNRIs) NNT=7·4 (5·6-10·9), NNH=13·9 (10·9-19·0; moderate certainty of evidence), botulinum toxin (BTX-A) NNT=2·7 (1·8-9·61), NNH=216·3 (23·5-∞; moderate certainty of evidence), capsaicin 8% patches NNT=13·2 (7·6-50·8), NNH=1129·3 (135·7-∞; moderate certainty of evidence), opioids NNT=5·9 (4·1-10·7), NNH=15·4 (10·8-24·0; low certainty of evidence), repetitive transcranial magnetic stimulation (rTMS) NNT=4·2 (2·3-28·3), NNH=651·6 (34·7-∞; low certainty of evidence), capsaicin cream NNT=6·1 (3·1-∞), NNH=18·6 (10·6-77·1; very low certainty of evidence), lidocaine 5% plasters NNT=14·5 (7·8-108·2), NNH=178·0 (23·9-∞; very low certainty of evidence). The findings provided the basis for a strong recommendation for use of TCAs, α2δ-ligands, and SNRIs as first-line treatments; a weak recommendation for capsaicin 8% patches, capsaicin cream, and lidocaine 5% plasters as second-line recommendation; and a weak recommendation for BTX-A, rTMS, and opioids as third-line treatments for neuropathic pain.

INTERPRETATION

Our results support a revision of the Neuropathic Pain Special Interest Group recommendations for the treatment of neuropathic pain. Treatment outcomes are modest and for some treatments uncertainty remains. Further large placebo-controlled or sham-controlled trials done over clinically relevant timeframes are needed.

FUNDING

NeuPSIG and ERA-NET Neuron.

The Pivotal Role of Arachnoid-Nerve Conflict in Trigeminal Neuralgia without Neurovascular Conflict

OBJECTIVE

The etiology of trigeminal neuralgia (TN) without neurovascular conflict (NVC) is unknown, and classic neurovascular decompression procedures are not applicable. We analyzed a potential etiology in patients operated on for TN without NVC.

METHODS

Clinical, radiological, and treatment outcome data were retrospectively reviewed in a consecutive cohort of 37 patients with medically intractable TN without detectable NVC on preoperative 3T magnetic resonance imaging or during surgery. All patients underwent endoscopic-assisted microsurgical trigeminal nerve release from tethering arachnoid between January 2019 and December 2023. Intraoperative findings were compared with findings of a control group of 22 patients undergoing surgery for other pathologies within the cerebellopontine angle.

RESULTS

Median age of 24 women and 13 men with TN was 58 years (interquartile range 48-71 years). Mean preoperative pain intensity scores on the visual analog scale and Barrow Neurological Institute scale were 9.5/10 and V, respectively. Surgical exploration revealed an arachnoid-nerve conflict in all cases of TN (cohort group) and in only 2 patients in the control group (P < 0.001). Release of the trigeminal nerve from its anchoring arachnoid yielded significant postoperative improvement of visual analog scale score (1.6/10, P < 0.001), and 84% of patients with TN became pain-free and medication-free (Barrow Neurological Institute score I) after a median postoperative follow-up of 24 months (interquartile range 7-46 months).

CONCLUSIONS

Arachnoid-nerve conflict seems to play a pivotal role in the etiology of TN without NVC. Trigeminal nerve release from tethering arachnoid effectively achieves pain relief and medication independence.

Predicting the efficacy of medical therapy in patients with trigeminal neuralgia

BACKGROUND

While MRI has proven valuable in predicting the surgical outcomes of trigeminal neuralgia (TN), studies on predicting the efficacy of medical therapy remain limited. The goal of this study was to identify MRI and clinical characteristics that could predict the efficacy of medical therapy for TN.

METHOD

We conducted a blinded evaluation of MRI characteristics in TN patients. Clinical data were obtained from medical records or follow-up phone calls. The relationship between MRI findings and clinical characteristics with the efficacy of medical therapy was then analyzed.

RESULTS

A total of 112 patients, including 44 men and 68 women, were enrolled in the study. After six months of follow-up, 35 patients (31.3 %) reported treatment failure, 30 patients (26.8 %) reported poor results, 19 patients (17.0 %) reported good results, and 28 patients (25.0 %) reported excellent results. Logistic regression analysis revealed that patients with the vertebral artery as the offending vessel were 5.625 times more likely to experience poor medical therapy efficacy (95 % confidence interval: 1.084-30.530, p = 0.040). In contrast, patients with involvement of the ophthalmic division (V1) of the trigeminal nerve were 0.416 times less likely to experience poor medical therapy efficacy (95 % CI: 0.178-0.974, p = 0.043).

CONCLUSION

Our study demonstrates that the vertebral artery as the offending vessel and involvement of the ophthalmic division of the TN are correlated with medical therapy efficacy. These findings may assist clinicians in providing more informed guidance when deciding between surgical and medical treatment options for TN patients.

The silent scream: Unraveling vagal nerve neuralgia; VANCOUVER syndrome and HeLPS

Cranial nerves are mechanically irritated by vascular compression in neurovascular compression syndromes. Vagus nerve neuralgia is one of the less prevalent types of Neurovascular Compression Syndromes. It can cause disorders like Hemilaryngopharyngeal Spasm (HeLPS) and Vagus Associated Neurogenic Cough (VANCOUVER syndrome). HeLPS presents with unilateral spasms of the throat and coughing, whereas VANCOUVER syndrome is typified by a chronic cough brought on by vascular encroachment on the rootlet of the vagus nerve. The diseases' clinical manifestations, diagnosis, differential diagnoses, and therapy approaches are discussed, emphasizing the role of microvascular decompression (MVD) in the case of conservative treatment failure. Due to vagus nerve neuralgia's similarities to other diseases, including psychiatric conditions and gastroesophageal reflux disease (GERD), it can be difficult to diagnose and treat. To make the best possible treatment decisions, the effectiveness of both conservative and surgical care modalities including MVD and medication is discussed.

Correlations between the blink reflex and magnetic resonance imaging in patients with trigeminal neuralgia

BACKGROUND

Trigeminal neuralgia is a disease characterized by severe facial pain that significantly reduces patients quality of life. Trigeminal neuralgia is subcategorized as idiopathic, classic or secondary. Magnetic resonance imaging is the basis for classification, but neurophysiological tests are also used. Magnetic resonance imaging provides neuroanatomical information and neurophysiological testing provides physiological information about the trigeminal nerve.

METHODS

Thirty volunteer patients who were diagnosed with trigeminal neuralgia according to the ICHD-3 diagnostic criteria and met the exclusion and inclusion criteria were included. Blink reflex testing was performed after posterior fossa magnetic resonance imaging. Magnetic resonance imaging was evaluated blindly to avoid bias by one radiologist experienced in neuroradiology.

RESULTS

The blink reflex was determined to be abnormal in 26.7% (n = 8) and normal in 73.3% (n = 22) of the patients included in the study. Magnetic resonance imaging revealed no contact with the trigeminal nerve in 53.3% (n = 16) of the patients, whereas 46.7% (n = 14) of the patients had contact with nerves in the cisternal segment. The blink reflex has sensitivity 42.9% and specificity 87.5%, accuracy value of 66.7%, positive predictive value of 75% and negative predictive value of 63.6% with respect to symptomatic mechanic contact.

CONCLUSION

The blink reflex is a neurophysiologic test that is well tolerated by patients, cost-effective and highly specific in the context of nerve contact in patients with trigeminal neuralgia. The blink reflex is particularly important in the follow-up and evaluation of trigeminal neuralgia patients for whom magnetic resonance imaging is contraindicated.

Trigeminal neuralgia and its comorbidities: a nationwide disease trajectory study

ABSTRACT

There is a limited understanding of risk factors and comorbidities in trigeminal neuralgia, a disease characterized by paroxysms of severe unilateral facial pain and a higher incidence in women. We aim to identify temporally associated comorbidities involving trigeminal neuralgia by analyzing nationwide disease trajectories. Using data from 7.2 million unique individuals in the Danish National Patient Register between 1994 and 2018, each individual diagnosed with trigeminal neuralgia was compared with 10,000 matched controls to identify co-occurring diseases. The sequential disease associations were identified in sex-stratified disease trajectories. A Cox-regression analysis investigated whether treatment with carbamazepine or oxcarbazepine, as compared with gabapentin, pregabalin, or lamotrigine, was associated with stroke risk. Finally, we investigated the stroke polygenic risk score and its association with stroke incidence in a subset of genotyped individuals with trigeminal neuralgia. We included 7141 individuals with trigeminal neuralgia (64.2% female, mean age at diagnosis 58.7 years) and identified 18 diseases associated with subsequent trigeminal neuralgia. After diagnosis, trigeminal neuralgia was associated with 9 diseases, including ischemic stroke (relative risk 1.55). Carbamazepine or oxcarbazepine treatment increased the ischemic stroke risk (hazard ratio 1.78; 95% confidence interval 1.47-2.17); however, the polygenic risk of stroke showed no association. In the Danish population, a trigeminal neuralgia diagnosis is temporally associated with 27 diseases revealed in systematic disease trajectories. Trigeminal neuralgia itself and its first-line treatment, but not a stroke polygenic risk score, was associated with an increased risk of ischemic stroke indicating that vascular risk factors should be routinely assessed in individuals with trigeminal neuralgia.

Effects of diagnosed depression on postoperative outcomes after microvascular decompression for patients with trigeminal neuralgia

BACKGROUND AND OBJECTIVES

Depression is believed to be prevalent in patients with trigeminal neuralgia (TN); however, its effect on postoperative outcomes in patients undergoing microvascular decompression (MVD) is not well understood. This study aims to characterize the association between a history of diagnosed depression and postoperative outcomes in patients undergoing MVD for TN.

METHODS

The medical records for 1007 patients with TN who underwent MVD at our institution from 2007 to 2023 were reviewed. Demographic characteristics, comorbid conditions, clinical TN characteristics, pain recurrence, and pre-operative and post-operative Modified Barrow Neurological Institute (BNI) pain and numbness scores were compared between groups. Differences in pain outcomes were evaluated via multivariate ordinal regression, Kaplan-Meier analysis, and Cox proportional hazards analysis.

RESULTS

181 (18.0 %) of patients had diagnosed depression. Patients with depression were younger (p = 0.005), more often female (p < 0.001), and more likely to be White (p = 0.012). Type 2 TN was more common in those with depression (p < 0.001). Depression was independently associated with higher pain at last follow-up (p = 0.009), less time to recurrent pain on Kaplan-Meier analysis (p = 0.0063), and was predictive of recurrent pain on Cox proportional hazards regression (p = 0.048).

CONCLUSION

A diagnosis of depression in patients undergoing MVD for TN is associated with greater postoperative pain and increased risk of pain recurrence, suggesting that depression is not only highly prevalent in patients with TN, but also may contribute to worse outcomes. These findings emphasize the need for adequate psychiatric screening before MVD and have implications for the preoperative counseling and management of this population.

Trigeminal reflex testing abnormalities as a predictive model for distinguishing classical and idiopathic trigeminal neuralgia

OBJECTIVE

Primary trigeminal neuralgia (TN) is a representative neuropathic facial pain condition classified into classical (associated with neurovascular compression), and idiopathic (unknown etiology). Differentiating between classical and idiopathic TN based on clinical and neurophysiological findings remains challenging. In this clinical and neurophysiological study, we aimed to identify predictive clinical and neurophysiological variables that may distinguish between the two types of TN.

METHODS

We retrospectively analyzed clinical records and neurophysiological data from 114 patients with primary TN (84 classical TN, 30 idiopathic TN). We implemented a logistic regression model to identify predictive variables for classical and idiopathic TN.

RESULTS

The logistic regression model showed that a trigeminal reflex latency asymmetry longer than 0.5 ms between the affected and unaffected sides was predictive of classical TN (p < 0.05). Additionally, combined involvement of the second and third trigeminal divisions was predictive of idiopathic TN (p < 0.05).

CONCLUSIONS

Our findings suggesting that latency asymmetry in trigeminal reflexes differentiate between classical and idiopathic TN probably reflects the association of classical TN with neurovascular compression, while idiopathic TN may involve other factors affecting trigeminal nerve fibers.

SIGNIFICANCE

Our results enhance our understanding of pathophysiology of TN and could improve clinical differentiation between its types.

A Case Report of Intraoral Injection of Botulinum Toxin A for Trigeminal Neuralgia: A Rare but Safe Intervention

Although off-label, according to the recommendations from guidelines, subcutaneous injections with botulinum toxin A in a follow-the-pain pattern are increasingly being used in trigeminal neuralgia. Subsequently, we report on an elderly woman with trigeminal neuralgia who responded well to intraoral therapy in addition to the subcutaneous injections in the dermal area of the affected trigeminal branch.

Trigeminal Neuralgia Treatment via Piezosurgical Enlargement of the Mental Foramen

Background: This article and the novel surgical approach described here were inspired by the ideas and observations of the late professors T. Pawela and J. Wnukiewicz. The authors present the medical history and unique surgical treatment of four patients with trigeminal neuralgia, who, despite pharmacological treatment and numerous specialists being involved in the treatment process, continued suffering. Our belief is that the direct cause of the symptoms is a narrow mental foramen, which compresses the mental nerve. It can be easily verified by local anesthesia administration to verify the trigger point, and by analyzing CBCT scans with a special emphasis on the diameter of both mental foramina. Methods: Surgical decompression by narrow mental foramen enlargement was conducted with a piezosurgical device. In this procedure, a rectangle of cortical bone is gently and precisely cut around the mental foramen and then into smaller pieces. This technique enables its easy and safe removal. Then, the mental nerve is left loose, uncompressed. Results: All four patients reported immediate recovery, their pain attacks stopped, and their quality of life improved significantly. One patient reported temporal hypoesthesia that lasted 5 months post-op. About 2 years post-op, another patient reported rare recurrences of pain, although much less severe than before surgery. Conclusions: This type of treatment may be considered when trigeminal neuralgia cannot be classified as classic or as secondary and is unresponsive to pharmacological treatment. A piezosurgical device seems to be the safest option in terms of potential damage to the nerve. Further research should include a larger sample of patients and focus on analyzing the mental foramina diameter of patients with idiopathic trigeminal neuralgia.

Automatic Segmentation of the Cisternal Segment of Trigeminal Nerve on MRI Using Deep Learning

Purpose: Accurate segmentation of the cisternal segment of the trigeminal nerve plays a critical role in identifying and treating different trigeminal nerve-related disorders, including trigeminal neuralgia (TN). However, the current manual segmentation process is prone to interobserver variability and consumes a significant amount of time. To overcome this challenge, we propose a deep learning-based approach, U-Net, that automatically segments the cisternal segment of the trigeminal nerve. Methods: To evaluate the efficacy of our proposed approach, the U-Net model was trained and validated on healthy control images and tested in on a separate dataset of TN patients. The methods such as Dice, Jaccard, positive predictive value (PPV), sensitivity (SEN), center-of-mass distance (CMD), and Hausdorff distance were used to assess segmentation performance. Results: Our approach achieved high accuracy in segmenting the cisternal segment of the trigeminal nerve, demonstrating robust performance and comparable results to those obtained by participating radiologists. Conclusion: The proposed deep learning-based approach, U-Net, shows promise in improving the accuracy and efficiency of segmenting the cisternal segment of the trigeminal nerve. To the best of our knowledge, this is the first fully automated segmentation method for the trigeminal nerve in anatomic MRI, and it has the potential to aid in the diagnosis and treatment of various trigeminal nerve-related disorders, such as TN.

From Tics to Stabs: Renaming Cluster Tics in Cluster Headache-A Cross-Sectional Study

BACKGROUND

Short-lasting paroxysms of facial pain in patients with cluster headache have traditionally been called "cluster tics." Mostly described as co-occurring trigeminal neuralgia, they remain to be explored as an independent phenomenon. We investigated the prevalence of cluster tics in cluster headache, the clinical differentiation from trigeminal neuralgia, and propose a distinct definition and renaming of cluster tics.

METHODS

We conducted a retrospective, controlled, cross-sectional study using semi-structured interviews of patients with cluster headache at the Danish Headache Center. A comparator cohort of patients with trigeminal neuralgia was included from a previous study. We investigated the lifetime prevalence of cluster tics in the cluster headache group and characterized them according to duration, location, pain-intensity, triggerability, and serial occurrence.

RESULTS

We included 424 participants with cluster headache (median age 52 years (IQR: 32-72), male-female ratio 3:2) and 576 participants with trigeminal neuralgia (median age 72 years (IQR: 50-94), male-female ratio 1:3). Cluster tics were reported by 200 (47%) cluster headache participants with higher odds for participants of female sex (OR: 1.94, 95% CI: 1.27-2.96, p = 0.002) and participants with chronic cluster headache (OR: 1.74, 95% CI: 1.15-2.63, p = 0.008). Unlike trigeminal neuralgia, cluster tics were not triggerable (OR: 0.02, 95% CI: 0.01-0.04, p < 2e-16) and presented with pain restricted to the first trigeminal division.

CONCLUSIONS

Cluster tics are prevalent in nearly half of patients with cluster headache, associated to female sex and chronic phenotype. Unlike trigeminal neuralgia, cluster tics occur in the orbital region and are largely non-triggerable. To improve terminology, we propose renaming cluster tics to "cluster stabs."

An Application of Combined Transpetrosal Approach With Microneurovascular Transposition in Recurrent Trigeminal Neuralgia Caused by Dolichoectatic Vertebral Artery

BACKGROUND

In general, the superior cerebellar artery is the most prevalent vessel that compresses the trigeminal nerve root exit zone (TGNREZ) and is responsible for trigeminal neuralgia (TGN). Nevertheless, the surgical outcome is less efficacious when the offending vessel is a dolichoectatic vertebrobasilar vessel (DVB). In addition, the potential for postprocedural adhesion and fibrosis renders recurrent TGN after prior surgery, an extremely challenging operation.

METHODS

We describe our surgical strategy and procedure that effectively resolved recurrent TGN in a patient whose offending vessel was a large DVB following standard microvascular decompression surgery. The size and nature of the offending DVB indicated that there was limited space for mobilization away from the TGNREZ, as evidenced by previous operative findings. Consequently, the patient's TGN may not be effectively treated by reoperating with the same standard lateral suboccipital approach.

RESULTS

Our surgical approach comprised the creation of an expanded area to facilitate the mobilization of the DVB from the TGNREZ, as well as the untethering of the trigeminal nerve and its subsequent mobilization from the DVB using the transposition technique.

CONCLUSIONS

A combined transpetrosal approach with microneurovascular transposition technique was selected to achieve all objectives. A case illustration with a surgical video is demonstrated.

Surgical Outcomes Following Distal Nerve Decompression in Patients With Trigeminal Neuralgia

Background

Patients with headache disorders may present with compression of distal trigeminal nerve branches as well as other head and neck nerve branches such as the occipital nerves. In addition, a coexisting diagnosis of trigeminal neuralgia of proximal origin may be present. This overlap in diagnoses complicates treatment. Therefore, this study aimed to investigate the therapeutic effects of distal nerve decompression surgery in patients with coexisting trigeminal neuralgia from a proximal origin.

Methods

The charts of 1112 patients who underwent screening for nerve decompression surgery were retrospectively reviewed. Patients with trigeminal neuralgia who underwent nerve decompression surgery were included. Data regarding preoperative and postoperative pain characteristics were collected.

Results

Seventeen (1.5%) patients met the inclusion criteria and underwent nerve decompression. Fifteen patients (56%) underwent occipital decompression (13 greater occipital nerve decompressions, and 10 lesser occipital nerve decompressions), 5 patients (19%) underwent frontal decompression (supraorbital nerve/supratrochlear nerve decompression), and 6 patients (22%) underwent temporal decompression (4 zygomaticotemporal decompressions and 2 auriculotemporal nerve decompressions). Among the patients who underwent occipital decompression, 11 (73%) patients reported ≥80% pain relief, 1 (6.7%) patient reported ≥50% pain relief, and 3 (20%) patients reported ≤20% pain relief. For frontal and/or temporal decompression, only 2 (28%) patients achieved substantial pain relief (100% and 50%), whereas 5 (71%) patients experienced ≤20% pain relief.

Conclusions

Our results demonstrate that occipital nerve decompression is an effective treatment for alleviating occipital neuralgia in individuals with coexisting proximal trigeminal neuralgia. However, the outcomes of frontal and temporal decompression were less favorable.

Effect of autophagy blockage on trigeminal neuropathic pain in rats: Role of microglia

Microglia activation and autophagy changes are associated with the regulation of pain, but no study to date has been designed to address whether these features apply to trigeminal neuropathic pain. This study aimed to investigate how alterations in autophagy affect nociceptive behaviors may be associated with microglia activation in the caudal part of the spinal trigeminal nucleus (SpVC) in a rat model of trigeminal neuropathic pain. This model was established by chronic constriction injury of the infraorbital nerve. Autophagy inhibitors and agonists were injected into the lateral ventricle to regulate autophagy. The autophagy markers microtubule-associated protein light chain 3 I (LC3-I), LC3-II, sequestosome1 (p62), and LC-3 were examined by western blotting and/or immunofluorescence. The microglia marker ionized calcium binding adapter molecule 1 (Iba-1) was examined by immunohistochemistry. Nociceptive behavior changes were detected by measuring the mechanical thresholds and face-grooming duration. The results showed that microglia in SpVC were activated, and autophagy flux was blocked in the trigeminal neuropathic pain model. Autophagy agonists inhibited microglia activation and alleviated nociceptive behaviors. In contrast, autophagy inhibitors further activated microglia and exacerbated nociceptive behaviors. In a rat model of trigeminal neuropathic pain, autophagy blockage leads to microglia activation, which significantly influences nociceptive processes.

Evaluation of the efficacy of ultrasound-guided maxillary and mandibular nerve pulsed radiofrequency treatment for trigeminal neuralgia and factors associated with successful response: a retrospective study

BACKGROUND

This study aimed to investigate the treatment efficacy and clinical and demographic characteristics affecting treatment success in patients who underwent ultrasound (US)-guided pulsed radiofrequency (PRF) to the maxillary and/or mandibular nerves for trigeminal neuralgia.

METHODS

The data of patients with trigeminal neuralgia who underwent US-guided maxillary and/or mandibular nerve PRF between September 2022 and December 2023 were reviewed and the study was retrospectively designed. Good analgesia was defined as ≥ 50% reduction in pain score at 3 months after the procedure, and the demographic and clinical characteristics of the patients were assessed.

RESULTS

Among the 72 included patients, 39 (54.2%) and 33 (45.8%) were classified as responders and non-responders, respectively. The age, pre- and post-procedural Numerical Rating Scale (NRS) scores, pain duration, and presence of constant pain were significantly lower in the responders. Logistic regression analysis revealed that older age (OR = 0.899, p < 0.001), high pre-procedural NRS scores (OR = 0.177, p = 0.009) and non-idiopathic (secondary or classic) etiology (OR = 0.062, p = 0.048) were significantly associated with an unsuccessful response to maxillary/mandibular PRF treatment.

CONCLUSION

This study is the first clinical trial to evaluate the efficacy of PRF therapy of the maxillary and mandibular nerves in the treatment of trigeminal neuralgia and demonstrated a significant reduction in pain scores at 3 months. Older age, high pre-procedural NRS scores, and non-idiopathic (secondary or classical) etiology are independent predictors of poor response to ultrasound-guided maxillary/mandibular nerve pulse radiofrequency treatment.

Efficacy and clinical outcomes of percutaneous treatments for trigeminal neuralgia secondary to multiple sclerosis

BACKGROUND

People with Multiple Sclerosis (MS) have a 20-fold higher risk of developing trigeminal neuralgia compared to the general population. Treating trigeminal neuralgia in these patients is particularly challenging due to reduced tolerance and increased side effects from medications. When no neurovascular conflict exist, percutaneous treatments are usually the first option after drug therapy. According to the literature, treatment outcomes for MS-associated trigeminal neuralgia show higher relapse rates and lower rates of sustained pain relief compared to primary trigeminal neuralgia, often necessitating multiple procedures.

METHODS

We conducted a retrospective cohort study of patients who underwent percutaneous procedures for trigeminal neuralgia between 2010 and 2021 at Rouen University Hospital. The patients were divided into two groups based on the presence or absence of multiple sclerosis. The primary endpoint was the postoperative Barrow Neurological Institute (BNI) pain score, categorized as favourable (I-III) or unfavourable (IV-V) at 3 months postoperatively and at the last date of follow-up.

RESULTS

Patients with multiple sclerosis were younger, had fewer comorbidities, and experienced more bilateral trigeminal pain compared to those without multiple sclerosis. BNI score evaluations at 3 months and at the last follow-up did not differ significantly between the two groups, with 81 % and 77 % of patients, showing favourable outcomes. However, the recurrence of pain after percutaneous procedures was significantly higher in patients with multiple sclerosis (p < 0.05).

CONCLUSION

Percutaneous rhizotomies achieve satisfactory clinical outcomes in patients with MS, despite a higher incidence of recurrences and subsequent percutaneous procedures compared to the general population.

Canadian Association of Radiologists Central Nervous System Diagnostic Imaging Referral Guideline

The Canadian Association of Radiologists (CAR) Central Nervous System Expert Panel is made up of physicians from the disciplines of radiology, emergency medicine, neurosurgery, and neurology, a patient advisor, and an epidemiologist/guideline methodologist. After developing a list of 24 clinical/diagnostic scenarios, a rapid scoping review was undertaken to identify systematically produced referral guidelines that provide recommendations for one or more of these clinical/diagnostic scenarios. Recommendations from 55 guidelines and contextualization criteria in the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) for guidelines framework were used to develop 51 recommendation statements across the 24 scenarios. This guideline presents the methods of development and the referral recommendations for congenital disorders of the brain, cerebrovascular disease, multiple sclerosis and demyelinating disease, headache, concussion, pituitary and juxtasellar lesions, cranial neuropathy, brain stem symptoms, altered intracranial pressure (hypertension, hypotension, hydrocephalus suspected shunt malfunction, normal pressure hydrocephalus), vestibular and cochlear symptoms (hearing loss, vertigo), mental status change (acute, dementia/memory loss), visual loss, epilepsy and seizure, CNS infection, intracranial space-occupying lesions, suspected cerebral venous sinus thrombosis, vasculitis, movement disorders/Parkinsonism, metabolic and toxic encephalopathies, and aneurysm screening.

Nervus Intermedius Neuralgia

PURPOSE OF REVIEW

This review discusses the diagnosis and treatment of nervus intermedius neuralgia (NIN) and identifies gaps in the literature.

RECENT FINDINGS

The nervus intermedius is a branch of the facial nerve. NIN presents as a rare neuralgia of this nerve, causing deep ear pain, which may radiate to the auditory canal, auricle, mastoid, soft palate, temple, and angle of the jaw. NIN most commonly presents in middle-aged women; neurovascular compression involving the anterior inferior cerebellar artery is the most common etiology described. Despite its diagnostic criteria in the International Classification of Headache Disorders, 3rd edition (ICHD-3), NIN may lack a trigger zone and may manifest as achy or neuralgiform pain instead of the typically described sharp or shooting pain. Like trigeminal neuralgia, NIN can be divided into classic, idiopathic, secondary, or painful neuropathy. Although there are no established guidelines for treating NIN, many possible treatments are used. Experience from treating trigeminal neuralgia suggests that carbamazepine or oxcarbazepine can be considered first-line. Patients with medically refractory NIN may benefit from neurosurgery referral for microvascular decompression or nerve sectioning. More research is needed to elucidate the range of clinical presentations in patients with NIN. Current data are limited and suggest that symptoms may diverge from the ICHD-3 diagnostic criteria. Although various treatments have been attempted, they often lack solid evidence and are typically derived from approaches used for other neuralgias. Proper diagnosis is crucial, particularly when considering surgical referral, due to the potential overlap of NIN with other neuralgias affecting the head and neck.

Surgical treatment of cerebellar pontine angle lipoma combined with trigeminal neuralgia: A case report

RATIONALE

Cerebellar pontine angle lipomas with trigeminal neuralgia are rare. The treatment choice is influenced by whether the pain is caused by the lipoma or the compression of blood vessels. Herein, we aimed to report a case of the disease and provide a reference for its treatment.

PATIENT CONCERNS

The patient was a 54-year-old female who presented with a 20-year history of left-sided facial pain. Her pain had gradually worsened over time and oral medications became progressively less effective.

DIAGNOSES

Brain magnetic resonance imaging detected a left cerebellar horn lesion, which was deemed a lipoma. Three-dimensional time-of-flight magnetic resonance angiography revealed a superior cerebellar artery adjacent to the trigeminal nerve root. Trigeminal nerve roots may have been compressed by lipomas and blood vessels.

INTERVENTIONS

The patient underwent a microvascular decompression of the trigeminal nerve. Part of the lipoma was removed, and the trigeminal nerve was isolated from the blood vessels and tumor.

OUTCOMES

Postoperative pathology confirmed a lipoma. Neuralgia was completely relieved postoperatively, and no new neurological disorder was detected during the 6-month follow-up.

LESSONS

Surgery is recommended for patients with cerebellar pontine angle lipomas combined with trigeminal neuralgia when conservative treatment fails. Detailed preoperative imaging is crucial to identify lipomas and trigeminal root compression by the responsible artery. Complete decompression of the trigeminal nerve root is necessary for complete pain relief.

Pathogenesis, Diagnosis, and Management of Trigeminal Neuralgia: A Narrative Review

Trigeminal neuralgia (TN) is an excruciating neurological disorder characterized by intense, stimulus-induced, and transient facial stabbing pain. The classification of TN has changed as a result of new discoveries in the last decade regarding its symptomatology, pathogenesis, and management. Because different types of facial pain have different clinical therapy and neuroimaging interpretations, a precise diagnosis is essential. Diagnosis should include magnetic resonance imaging with specific sequences to rule out secondary causes and to identify possible neurovascular contact. The purpose of demonstrating a neurovascular contact is to aid in surgical decision making, not to validate a diagnosis. Microvascular decompression is the first-line procedure for individuals who do not respond to medical management, whereas carbamazepine and oxcarbazepine are the preferred medications for long-term care. New developments in animal models and neuroimaging methods will shed more light on the biology and etiology of TN. This paper reviews the pathogenesis, the clinical features, the diagnosis, and the management of TN. Furthermore, the potential role of low-intensity pulsed ultrasound in neurological disorders is discussed.

Intravenous fosphenytoin therapy for the rescue of acute trigeminal neuralgia crisis in pre- and post-neurosurgical patients: a retrospective observational study

Background

There is no established treatment for the acute exacerbation of trigeminal neuralgia. We aimed to investigate the efficacy and safety of intravenous fosphenytoin for this disease.

Methods

We conducted a retrospective observational study of data from 41 patients with trigeminal neuralgia who received intravenous fosphenytoin therapy. Fosphenytoin diluted with physiological saline was administered intravenously at a loading dose of 9.8-20.7 mg/kg or at a dose of 7.5-9.5 mg/kg when maintenance therapy was needed. Pain was evaluated using a numerical rating scale (NRS), assessed immediately before administration (baseline) and at 2, 12, and 24 h after administration.

Results

The mean (± standard deviation) NRS score was 9.85 ± 0.69, 0.49 ± 1.47, 1.60 ± 2.19, and 3.46 ± 3.19 at baseline, 2, 12, and 24 h after administration, respectively (p < 0.001). Intravenous fosphenytoin therapy was effective for the acute exacerbation of trigeminal neuralgia regardless of whether it was administered during the perioperative period of microvascular decompression (MVD) or the type of drugs used concomitantly. Fosphenytoin was effective when re-administered (n = 14) or at a maintenance dose (n = 2). The adverse drug reactions observed were mild dizziness in six patients, abnormal auditory perception and thirst in three patients each, and somnolence, decreased SpO2, and drug eruption in one patient each, all of which were transient.

Conclusions

Intravenous fosphenytoin therapy can immediately eliminate pain during acute exacerbation of trigeminal neuralgia and can be a useful therapeutic drug in emergency response or until elective treatment, such as MVD, is performed.

Percutaneous ballon compression, a better choice for primary trigeminal neuralgia compared to microvascular decompression?

Objective

Demonstrate the superiority of percutaneous balloon compression (PBC) in the treatment of primary trigeminal neuralgia (PTN) compared to trigeminal microvascular decompression (MVD).

Methods

Clinical data, including immediate, short-term, and long-term pain relief, complications, duration of the operation, and postoperative hospital stay, were retrospectively analyzed for 114 patients diagnosed with PTN who were treated with either PBC or MVD between January 2018 and December 2021.

Results

There were no statistically significant differences observed in the pain relief rates between the two surgical methods at 24 h postoperatively (MVD: 91.07%, PBC: 96.55%), at 6 months postoperatively (MVD: 87.5%, PBC: 94.8%), at 1 year postoperatively (MVD: 83.90%, PBC: 94.80%), and at 2 years postoperatively (MVD: 78.60%, PBC: 72.40%). However, the incidence of meningitis following MVD was significantly higher than that following PBC (P < 0.005). Additionally, both the duration of the operation and the length of the postoperative hospital stay in the MVD group were longer than those in the PBC group (P < 0.005).

Conclusion

PBC demonstrates efficacy comparable to MVD while offering a simpler procedure, improved safety, and a shorter postoperative hospital stay. Therefore, it may serve as a viable alternative to MVD and could become the preferred surgical approach for treating PTN in the future.

Effectiveness of Radiofrequency in Treating Pain Associated With Trigeminal Neuralgia in Oncologic Patients

Introduction In cancer patients, trigeminal neuralgia (TN) has been not only observed in its secondary form but also described as one of the common neuropathic pain syndromes related to cancer. Patients with TN experience a marked reduction in quality of life due to the nature and severity of the pain. Although the standard treatment is microvascular decompression, this approach is not always feasible in oncologic patients. Therefore, radiofrequency (RF) guided by tomography has been described as an ablative intervention that allows achieving immediate pain relief in TN. It is of interest to identify the therapeutic response to pain in oncologic patients treated by this procedure. Objective The study aimed to evaluate the effectiveness of percutaneously guided tomography-assisted RF in oncologic patients with TN. Materials and methods We conducted an observational, retrospective, longitudinal, and analytical study. Patients with cancer and TN treated at the Pain Clinic of the National Cancer Institute in Mexico, who underwent RF, were included. A non-probabilistic sampling of consecutive cases was used, and selection criteria were applied. Clinical records were reviewed to measure study variables, including pain by TN before and after the procedure, as well as patient satisfaction. Data were analyzed using descriptive and inferential statistics, employing Student's t-test for related samples, with a significant level set at p ≤ 0.05 to determine statistical significance. The recorded data were analyzed using IBM SPSS Statistics for Windows, V. 26.0 (IBM Corp., Armonk, NY, USA). Results In the sample of 76 subjects (50% women and 50% men) with a mean age of 60.6 years, a variety of oncologic diagnoses were presented, with skin and soft tissue tumors being the most frequent, mainly located at the level of the head and neck. The etiology of TN was secondary in most cases (89.5%), with similar anatomical involvement on both hemifaces (50% left, 50% right). The branches most frequently involved were the maxillary nerve (V2) and mandibular nerve (V3) (39.5%) and V3 alone (22.4%). The most common probable cause was tumor activity (53, 69.7%). Most patients were receiving anticonvulsant treatment (carbamazepine-oxcarbazepine) (58.9%), followed by gabapentinoids (31.5%). Of the 76 patients, only six received computed tomography (CT)-guided RF. No complications associated with RF application were reported. The mean baseline pre-procedure pain (3.8 ± 2.48) and mean baseline post-procedure pain (2.17 ± 1.94) were significantly different in the Wilcoxon signed-rank test (p = 0.043), as were the mean incidental pre-procedure pain (9.0 ± 1.09) and mean incidental post-procedure pain (5.8 ± 2.31) (p = 0.019).  Conclusions Our research provides relevant data on the effectiveness of RF in managing TN in oncologic patients, demonstrating a clinically and statistically significant reduction in pain intensity. These findings need to be confirmed through prospective, longitudinal, long-term studies with control groups in a larger number of patients.

Risk factors for postoperative recurrence after full-endoscopic microvascular decompression for trigeminal neuralgia: a retrospective study and predictive nomogram

BACKGROUND

Full-endoscopic microvascular decompression (fE-MVD) is an emerging treatment option for trigeminal neuralgia (TN). However, the risk factors associated with postoperative recurrence of TN after fE-MVD procedure remain controversial. The aim of the present study was to summarize the surgical technique of fE-MVD for the treatment of TN and to develop a predictive model for recurrence at 1 year postoperatively based on independent risk factors.

METHODS

A total of 124 consecutive patients with TN who underwent fE-MVD procedure were enrolled in this study between December 2008 and July 2022. Imaging data such as the area of cerebellopontine angle (CPA), the length of trigeminal cisternal segment, and the angle of trigeminal nerve (TGN) were measured from preoperative magnetic resonance imaging (MRI). Patients were randomly divided into a training set and a validation set according to the 7:3 ratio, respectively. Variables that were significant in the univariate logistic analyses were, subsequently, included in the multivariate logistic regression analyses in training set. Then, we developed a predictive nomogram for the 1-year recurrence of TN for patients who treated with fE-MVD.

RESULTS

All 124 patients experienced clinically significant pain relief (Barrow Neurology Institute (BNI) I-II) after fE-MVD. 124 patients had a follow-up time of more than 1 year, with 14 cases of recurrence. In the univariate analysis, the patients' responsible vessels of non-arterial, clinical features of atypical, and CPA area ratio (healthy/affected side) >1 were found to be significantly associated with recurrence of TN after fE-MVD. Multivariate logistic regression analyses result showed that the patients' responsible vessels of non-arterial (odds ratio (OR) = 21.067, 95% confidence interval (CI): 1.942-228.575), clinical features of atypical (OR = 9.027, 95% CI: 1.135-71.777), and CPA area ratio >1 (OR = 19.522, 95% CI: 2.906-131.160) were independent predictors of TN recurrence. Based on the independent predictive factors, we developed a predictive nomogram that predicts the 1-year recurrence of TN after fE-MVD. In the receiver operating characteristic (ROC) curve analysis, the area under the curve (AUC) of the nomograms for 1-year recurrence associated with optimal candidates prediction was 0.910 in the training set and 0.859 in the validation set.

CONCLUSIONS

FE-MVD for the treatment of TN is a safe, reliable and effective procedure. Patients' responsible vessels of non-arterial, clinical features of atypical, and CPA area ratio (healthy/affected side) >1 are key risk factors associated with 1 year postoperative recurrence of TN after fE-MVD. Finally, we have developed a nomogram to predict the 1-year recurrence of TN for patients who treated with fE-MVD, which can be used to provide advice for patients after fE-MVD.

Long-term outcomes of Gamma Knife radiosurgery for trigeminal neuralgia patients with or without concomitant continuous pain

The effectiveness of Gamma Knife radiosurgery (GKRS) in treating trigeminal neuralgia (TN) has been demonstrated by a number of previous studies. However, there is a lack of research specifically documenting the initial and long-term outcomes of paroxysmal and persistent pain respectively following GKRS for TN with concomitant continuous pain (CCP). This study retrospectively analyzed pain outcomes and complications in 46 TN patients with CCP and 112 patients without CCP who underwent GKRS as initial surgical intervention at our institution from January 2019 to January 2024. Pain outcomes were classified as excellent (BNI I), good (BNI II-IIIa), and poor (BNI IIIb-V). Demographic and clinical data, pain outcomes, and complications were compared between patients with and without CCP. Subsequently, risk factors for poor outcomes after GKRS were evaluated using univariate and multivariate Cox regression analysis. The initial rate of poor outcomes in TN patients with CCP was similar to that of patients without CCP (15.8% vs 14.4%, P = .878). Following a minimum 6-month follow-up, the rate of poor pain outcomes increased to 37.0% in patients with CCP, compared to 38.4% in those without CCP (P = .968). Notably, the rate of long-term complete pain relief in patients without CCP was significantly higher than in those with CCP (35.7% vs 15.2%, P < .001). Poor response to medication (P < .001) was identified as an independent risk factors for poor outcomes after GKRS. While most TN patients with or without CCP can achieve favorable pain outcomes after GKRS, individuals with CCP were less likely to achieve complete pain relief compared to those without CCP.

Pathophysiology and Management of Refractory Trigeminal Neuralgia

PURPOSE OF REVIEW

Discuss the current understanding of the pathophysiology and management of refractory trigeminal neuralgia (TN). This includes a discussion on why TN can recur after microvascular decompression and a discussion on "outside of the box" options when both first- and second-line management strategies have been exhausted.

RECENT FINDINGS

This review discusses second- and third-line oral medication options, botulinum toxin A, repeat microvascular decompression, repeat ablative procedures, internal neurolysis, trigeminal branch blockade, and neuromodulation using TMS or peripheral stimulation. Additional management for chronic neuropathic facial pain such as deep brain stimulation, motor cortex stimulation, and focused ultrasound thalamotomy are also discussed, though evidence in trigeminal neuralgia is limited. Treatment of recurrent TN despite multiple surgeries can be challenging, and multiple minimally invasive and more invasive management options have been reported in small studies and case reports. Further studies are needed to determine an optimal stepwise approach.

Predictive value of MRI for identifying symptomatic neurovascular compressions in classical trigeminal neuralgia: a PRISMA-compliant meta-analysis

BACKGROUND

Patients with trigeminal neuralgia frequently undergo magnetic resonance imaging (MRI) prior to surgery. In patients without the signs and symptoms of face discomfort, MRI has shown the presence of neurovascular contact (NVC) in humans. Therefore, its capacity to accurately exclude NVC of the trigeminal nerve is not properly understood. A meta-analysis of the literature satisfied the criteria to further explore the value of MRI for the diagnosis of classical trigeminal neuralgia (CTN).

STUDY DESIGN

The association between the symptomatic and asymptomatic trigeminal nerves, NVC, root entry zone (REZ), non-REZ, and anatomical variation was measured by a comprehensive review and meta-analysis of 13 observational studies using MRI for CTN neurovascular compression diagnosis.

OBJECTIVES

This study aimed to evaluate the effectiveness of MRI in detecting the neurovascular compression that causes symptoms in individuals with classic trigeminal neuralgia.

SETTING

This study was conducted at the Department of Neurosurgery, Yantai Yuhuangding Hospital, Qingdao University.

METHODS

Digital searches of PubMed, Embase, and the Cochrane Library were performed to identify studies published until December 31, 2023. The following were evaluated: (1) MRI evidence of NVC in symptomatic and asymptomatic trigeminal nerves; (2) MRI indication of NVC at the REZ in symptomatic and asymptomatic trigeminal nerves; (3) MRI substantiation of non-REZ neurovascular contact in patients with CTN; and (4) asymptomatic and symptomatic anatomical changes at the NVC site of the trigeminal nerves. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using the fixed effects models.

RESULTS

We identified 13 observational studies (1 prospective and 12 retrospective studies) with data collected from 1770 nerves (728 symptomatic and 1042 asymptomatic) were meta-analyzed. First, MRI of 649/728 (88.2%) symptomatic versus 378/1042 (36.3%) asymptomatic trigeminal nerves revealed marked differences in NVC in the REZ (OR = 16.3; CI 95%=12.2-21.8; p < 0.00001). Second, pooled data showed that REZ NVC was detected in 206/262 (78.6%) symptomatic and in 129/340 (37.9%) asymptomatic nerves (OR = 5.0; CI 95% = 3.4-7.3; p < 0.00001); Third, no significant differences were detected between 44/267 (16.5%) symptomatic and 23/189 (12.1%) asymptomatic nerves on MRI examination of NVC in the NON-REZ (OR = 0.9; CI 95% 0.5-1.6) (p = 0.77); Finally, MRI revealed marked differences in 302/567 (53.2%) symptomatic and 73/919 (7.9%) asymptomatic anatomic changes (atrophy, dislocation, distorsion, flattening or indentation) at the NVC site of the trigeminal segments (OR = 11.9; CI 95% = 8.8-16.2; p < 0.00001).

LIMITATIONS

Despite the systematic evaluation of 13 observational studies, large-scale randomized controlled trials should be conducted, focusing on the specificity of MRI for the diagnosis of trigeminal neuralgia and evaluating the specificity of the imaging findings and the impact of the patient's postoperative treatment.

CONCLUSIONS

A previous meta-analysis showed that patients with CTN were more likely to have NVC-specific anatomical changes. MRI of patients with CTN can detect anatomical changes in the REZ NVC with higher sensitivity.

Immediate consecutive microvascular decompression for bilateral classical trigeminal neuralgia

Background

Classical trigeminal neuralgia (TN) is characterized by sudden, severe facial pain, typically resulting from a neurovascular conflict affecting the trigeminal nerve. In rare cases, both nerves are affected simultaneously causing bilateral TN (BTN), increasing the complexity of the treatment. Microvascular decompression (MVD) is a well-established treatment for TN; however, the experience with immediate consecutive bilateral MVD procedures is limited and requires further evaluation.

Objective

To evaluate the safety and efficacy of immediate consecutive bilateral MVD in patients with severe BTN compared to non-consecutive bilateral MVD procedures.

Methods

A retrospective analysis was conducted on 15 patients with BTN who underwent bilateral MVD. The data on clinical presentation, surgical technique, perioperative findings, complications, and follow-up outcomes of three cases of BTN treated with consecutive bilateral MVD surgeries were analyzed and compared to 12 who received separated procedures. Moreover, a detailed presentation of the three cases of consecutive MVD is provided to illustrate clinical decision-making, surgical nuances, and individual outcomes.

Results

Both groups achieved significant pain relief (p < 0.001) without notable differences in Barrow Neurological Institute (BNI) pain intensity score (p = 0.305), indicating that both approaches were equally effective. The consecutive MVD group experienced a shorter total surgical duration (p = 0.025), while postoperative complications were comparable (p = 0.077), mostly transient with no major adverse events or mortality. At the last follow-up, the patients remained pain-free without recurrence of TN symptoms.

Conclusion

Consecutive bilateral MVD is a safe and effective option, comparable to non-consecutive procedures for treating BTN. This approach provides a viable alternative for patients with severe bilateral symptoms or when medical constraints limit the possibility of two separate surgeries. Further studies with larger cohorts and extended follow-up periods are needed to support these results.

Clinical Efficacy of Two Different Low-Level Laser Therapies for the Treatment of Trigeminal Neuralgia: A Randomized, Placebo-Controlled Trial

Background: Trigeminal neuralgia (TN) is a disease that causes severe pain that can seriously affect the quality of life. This study aimed to compare the effectiveness of two different low-level laser therapies (LLLT) as alternatives to medical treatment to reduce pain and improve the quality of life in patients with TN. Methods: A total of 45 patients were randomly divided into 3 groups. In the first group, a new-generation diode laser (GRR laser) was applied at predetermined points in the trigeminal nerve line. In the second group, a low-level neodymium-doped yttrium aluminum garnet (Nd:YAG) laser was applied along the affected nerve line. The placebo group received the same protocol with a Nd:YAG laser without the device switched on. The scores were recorded pre- and post-treatment using the Brief Pain Inventory-Facial (BPI-facial) scale. Results: A statistically significant difference was found between the pre- and post-treatment values of all four variables in the GRR laser, Nd:YAG laser, and placebo groups. When the post-treatment values were compared, statistically significant differences were found between the groups in pain frequency, pain intensity, and interference in facial-specific activities, but no differences were found in general activities. Conclusions: Both LLLTs can be considered alternative treatment modalities for TN, but the GRR laser treatment was more effective than the Nd:YAG laser treatment in reducing pain and improving the quality of life in patients with TN.

Clinical pharmacology of neuropathic pain

This chapter aims to review the current pharmacological options for neuropathic pain treatment, their mechanisms of action, and future directions for clinical practice. Achieving pain relief in neuropathic pain conditions remains a challenge in clinical practice. The field of pharmacotherapy for neuropathic pain has encountered significant difficulties in translating substantial advances in our understanding of the underlying pathophysiological mechanisms into clinically effective therapies. This chapter presents the drugs recommended for the pharmacotherapy of neuropathic pain, based on the widely accepted treatment guidelines formulated by the Neuropathic Pain Special Interest Group of the International Association for the Study of Pain. In addition to discussing how the evidence base is created as part of international consortia, the drugs are also examined in terms of their putative molecular mechanisms as well as pharmacological pleiotropy, i.e., their potential unspecific and multi-target effects resulting in modulation of neuronal hyperexcitability. The chapter closes with a discussion of potential future developments in the field.

Neuropathic pain - A clinical primer

Neuropathic pain is used both as a mechanistic descriptor and a classification category of pain caused by a lesion or disease of the somatosensory nervous system and encompasses a vast array of possible diagnoses. The identification of neuropathic pain and diagnosis of specific syndromes relies on a detailed patient history. Standardized pain questionnaires can capture the patient`s symptoms, while the anatomical distribution of pain is often documented using pain drawings. Following this, a thorough clinical neurological examination is conducted to identify distinct sensory abnormalities, specifically sensory deficits and signs of increased sensitivity such as allodynia and hyperalgesia, within the pain-affected areas. Regardless of whether the lesion or disease is in the peripheral or central somatosensory nervous system, the presence of clinically overt sensory abnormalities is a key feature, distinguishing neuropathic pain from other types of pain, such as nociceptive pain, which likely coexist in neurological disorders. Extensive sensory deficits, as seen in certain stroke syndromes or following spinal cord injuries, may increase the likelihood of concomitant non-neuropathic pain within the same area of sensory loss. For this reason, differential diagnosis is essential when assessing patients with suspected neuropathic pain. Further diagnostic tests, including imaging or specific neurophysiological methods that assess nociceptive pathways, can provide objective evidence of a lesion or disease within the somatosensory nervous system. However, the causality between the lesion and the presence of neuropathic pain cannot be established definitively and always requires clinical judgment and interpretation within the broader context of the neurological disorder.

Effectiveness of thalamotomy with Gamma Knife radiosurgery as a multitarget strategy in patients with complex trigeminal neuralgia

Background

In the setting of refractory neuralgia or other complex facial pains, the intensity of the pain does not decrease despite medical and even surgical interventions. This report aims to describe the experience of an institution in the management of refractory trigeminal neuralgia and other complex facial pains with Gamma Knife radiosurgery (GKR), including thalamotomy as a multitarget strategy.

Methods

We conducted a retrospective observational study. Data were obtained from 50 patients with complex trigeminal neuralgia treated with GKR, in whom the thalamus was included as a target. The Visual Analog Scale (VAS) and the Barrow Neurological Institute (BNI) scale were considered before treatment and at the follow-up. The Wilcoxon test was used to compare the VAS scores and the McNemar test for the BNI scale.

Results

The mean age was 62.7 years (standard deviation = 16.3). The indications for management with thalamotomy were neuralgia refractory to medical management (68%), recurrent pain after previous rhizolysis with GKR (20%), atypical deafferentation-type pain in patients with radiofrequency background (10%), and anatomical deformation of the trigeminal nerve by a tumor (2%). Before treatment, all patients were classified as BNI V. At follow-up, a satisfactory response to treatment was described in 82.05% of cases (P = 0.001 McNemar). The median preoperative pain evaluated with VAS was 10 (interquartile range [IQR] = 10-10), while at follow-up, it was 6 (IQR = 1-7) (P = 0.001 Wilcoxon).

Conclusion

The thalamus is a versatile, effective, and safe therapeutic target for ablative management in patients with complex facial pain.

Pre-treatment DTI markers: predicting clinical outcomes in microvascular decompression for classic trigeminal neuralgia - a systematic review

BACKGROUND AND PURPOSE

Trigeminal neuralgia (TN) is a severe chronic pain condition, typically affecting patients over 50-year-old, caused by the compression of the nerve at the root entry zone (REZ) by blood vessels. While the diagnosis is clinical, advanced imaging like diffusion tensor imaging (DTI) is crucial to identify underlying causes and assessing nerve damage. DTI may help develop neuroimaging markers to improve understanding of TN and predict surgical outcomes. The goal of the present systematic review is to evaluate the effectiveness of DTI and tractography in order to better assess treatment planning and outcome prediction through the analysis of trigeminal nerve alterations.

METHODS

The authors conducted a systematic review and meta-analysis of the literature to compare radiological parameters identified in pre- and post-operative MRI with DTI sequences, including fractional anisotropy (FA), quantity of anisotropy (QA), radial diffusivity (RD), and to correlate these findings with post-operative clinical outcomes. A comprehensive search of the PubMed and Scopus databases was carried out for studies published between April 2010 and January 2024.

RESULTS

This review included 11 studies and 603 patients. Of the 363 patients with trigeminal neuralgia (TN), 193 underwent microvascular decompression (MVD), with 72.5% showing clinical improvement and 27.5% not improving, possibly due to chronic nerve damage. Four studies assessed radiological parameters before and after MVD, while two focused only on post-MVD data. The mean fractional anisotropy (FA) in affected nerves increased from 0.328 before MVD to 0.382 afterward. Five studies did not report postoperative outcomes, just comparing radiological parameters in TN patients versus healthy controls.

CONCLUSIONS

Recent studies show that MRI-DTI parameters, including FA, RD, and QA, are useful for diagnosing trigeminal neuralgia and predicting treatment outcomes. Lower FA and higher RD values indicate better results after surgery. More research is mandatory to guide treatment decisions and enhance patients' care.

MR-guided Focused Ultrasound Thalamotomy for Chronic Pain

MR-guided focused ultrasound (FUS) represents a promising alternative for patients with chronic neuropathic who have failed medical management and other treatment options. Early single-center experience with chronic neuropathic pain and trigeminal neuralgia has demonstrated favorable long-term outcomes. Excellent safety profile with low risk of motor and sensory complications and so far anecdotal permanent neurologic deficits make FUS a powerful tool to treat patients who are otherwise hopeless. Neuromodulation may be the most influential factor driving outcomes and studies devised to detect neuroplasticity will be critical to guide such therapies.

Abnormal electromyographical trigeminal activation through stimulation of the offending artery (Z-L response): An intraoperative tool during microvascular decompression for trigeminal neuralgia

BACKGROUND

There are currently no intraoperative neurophysiological tools to assess the effectiveness of trigeminal nerve decompression during microvascular decompression surgery for drug-resistant trigeminal neuralgia. In microvascular decompression surgery for hemifacial spasm, an abnormal electromyographic activation of facial muscles after stimulation of the offending vessel was identified and named 'Z-L response'.

METHODS

We adapted a neurophysiological protocol to elicit a Z-L response during microvascular decompression surgery for trigeminal neuralgia and applied it to a prospective series of 18 surgical patients.

RESULTS

Patients had suffered from trigeminal neuralgia for a median 9-year timeframe, and median preoperative Barrow Neurological Institute pain score was 4.5. Through monopolar stimulation, using rising amplitudes starting from 0.1 mA, we confirmed intraoperatively the true culprit vessel before decompression. In 4/18 cases, multiple offending vessels were identified (22 conflicts overall). After decompression, a significant increase in activation threshold (p < 0.0001) confirmed the effectiveness of the maneuver; in 10 cases, Z-L response was abolished. Using this technique, we obtained excellent or good outcome (Barrow Neurological Institute 1-3) in all patients, with a significant reduction in postoperative Barrow Neurological Institute score as compared with preoperative one (median Barrow Neurological Institute 1; p = 0.0002).

CONCLUSION

we provide the first evidence on the applicability and clinical usefulness of Z-L response during microvascular decompression surgery for trigeminal neuralgia.

What Is New and Effective in Treating Refractory Trigeminal Neuralgia?

Trigeminal neuralgia (TN) is a severe facial pain disorder characterized by brief, electric shock-like pain triggered by innocuous stimuli, commonly affecting middle-aged women. TN can be classified as classic, secondary, or idiopathic, with the secondary form linked to multiple sclerosis (MS). Treatment typically begins with carbamazepine or oxcarbazepine, but surgical and alternative treatments, including botulinum toxin type A (BoNT-A), may be considered for refractory cases. We present the case of a 47-year-old female with secondary progressive MS and refractory TN, initially diagnosed in 2008. Following a history of failed pharmacological and surgical interventions, including microvascular decompression and gamma knife surgery, the patient was admitted to a rehabilitation center for motor, cognitive, and functional recovery. Her severe pain, which did not respond to conventional medication, impaired her participation in rehabilitation, leading to the use of BoNT-A as a new intervention. A total of 100U of BoNT-A was injected subcutaneously across the most painful facial regions, at 1 cm intervals. Following the BoNT-A injection, the patient reported a marked reduction in pain (VAS score reduced from 8-9/10 to 1/10), less frequent exacerbations, and reduced dependence on emergency analgesics. The only adverse effect observed was transient ipsilateral facial paresis (House-Brackmann grade II). This case underscores the potential of BoNT-A as a valuable adjunctive therapy for TN, particularly in complex patients where traditional medical and surgical options have failed. BoNT-A was well-tolerated, providing substantial pain relief with minimal side effects. Despite the absence of standardized guidelines for its use in TN, this case supports its consideration in refractory cases, highlighting the need for further research to optimize dosing and administration techniques.

Predicting long-term outcomes in patients with classical trigeminal neuralgia following microvascular decompression with an MRI-based radiomics nomogram: a multicentre study

OBJECTIVES

This study aimed to develop a clinical-radiomics nomogram to predict the long-term outcomes of patients with classical trigeminal neuralgia (CTN) following microvascular decompression (MVD).

MATERIALS AND METHODS

This retrospective study included 455 patients with CTN who underwent MVD from three independent institutions A total of 2030 radiomics features from the cistern segment of the trigeminal nerve were extracted computationally from the three-dimensional steady-state free precession and three-dimensional time-of-flight magnetic resonance angiography sequences. Using the least absolute shrinkage and selection operator regression, 16 features were chosen to develop radiomics signatures. A clinical-radiomics nomogram was subsequently developed in the development cohort of 279 patients via multivariate Cox regression. The predictive performance and clinical application of the nomogram were assessed in an external cohort consisting of 176 patients.

RESULTS

Sixteen highly outcome-related radiomics features extracted from multisequence images were used to construct the radiomics model, with concordance indices (C-index) of 0.804 and 0.796 in the development and test cohorts, respectively. Additionally, a clinical-radiomics nomogram was developed by incorporating both radiomics features and clinical characteristics (i.e., pain type and degree of neurovascular compression) and yielded higher C-indices of 0.865 and 0.834 in the development and test cohorts, respectively. K‒M survival analysis indicated that the nomogram successfully stratified patients with CTN into high-risk and low-risk groups for poor outcomes (hazard ratio: 37.18, p < 0.001).

CONCLUSION

Our study findings indicated that the clinical-radiomics nomogram exhibited promising performance in accurately predicting long-term pain outcomes following MVD.

CLINICAL RELEVANCE STATEMENT

This model had the potential to aid clinicians in making well-informed decisions regarding the treatment of patients with CTN.

KEY POINTS

Trigeminal neuralgia recurs in about one-third of patients after undergoing MVD. The clinical-radiomics nomogram stratified patients into high- and low-risk groups for poor surgical outcomes. Using this nomogram could better inform patients of recurrence risk and allow for discussion of alternative treatments.

Treatment of trigeminal neuralgia by acupuncture combined with Chinese medicine from the perspective of modern medicine: A review

Trigeminal neuralgia (TN) is characterized by recurrent episodes of transient severe pain in its distribution area, with abrupt onset and termination. With the progression of the disease, patients are prone to concurrent psychiatric disorders, such as anxiety and depression, which seriously affect patients' quality of life. Currently, anticonvulsant drugs are commonly used in clinical practice as the primary treatment, but long-term use of drugs is prone to drug resistance, limiting clinical application. Acupuncture and traditional Chinese medicine (TCM), as alternative and complementary therapies, can make up for the deficiencies in modern medicine and are accepted by patients with the advantages of safety and effectiveness. TCM therapy works by promoting the release of endogenous opioid peptides, adjusting the level of inflammatory factors, and improving negative emotions to exert analgesic effects. This paper discusses the clinical efficacy and safety of acupuncture combined with Chinese medicine in the treatment of TN from the perspective of modern medicine and provides a theoretical basis for seeking better therapeutic targets.

Efficacy and safety of a third stereotactic radiosurgery for recurrent trigeminal neuralgia: an international, multicenter study

BACKGROUND AND OBJECTIVES

Trigeminal Neuralgia (TN) is a debilitating facial pain disorder, often necessitating surgical interventions when medication proves insufficient. Stereotactic Radiosurgery (SRS) is an established therapeutic option. Limited studies explored the feasibility of a third SRS procedure. Our study investigates the safety and efficacy of a third SRS procedure for recurrent TN.

METHODS

We performed a retrospective analysis across multiple centers using databases collected prospectively. Pain status was evaluated utilizing the BNI Pain Intensity Scales. The Kaplan-Meier method was employed to estimate the time to recurrence, with group comparisons conducted using log-rank tests. Associations were explored using Chi-square and logistic regression models.

RESULTS

Ten institutions contributed with a total of 35 patients. A third SRS revealed sustained effectiveness with a pain control rate of 82.7%. The median time to recurrence was 35.5 months. New sensory dysfunction following the third procedure occurred in 22% of patients who had preserved sensory function after the second procedure. When considering those who developed sensory dysfunction after the second procedure, 40% of the entire cohort was affected. There were no significant differences in pain recurrence intervals among the three procedures. A meta-analysis, combining data from previous studies, showed that 89.6% of patients achieved some degree of pain control after a third SRS, with 27.4% experiencing new sensory dysfunction and a median time to recurrence of 31.6 months.

CONCLUSION

Our study, the largest on the topic, affirms the sustained effectiveness of a third SRS for TN, providing comparable pain relief to initial procedures. Notably, an extended pain-free interval after the third SRS session was observed. Facial sensory dysfunction emerged as the primary side effect. Larger studies are warranted to explore correlations with demographics and treatment parameters for a comprehensive understanding of repeat SRS in managing recurrent TN.

Orofacial Pain

OBJECTIVE

This article explores the multiple etiologies, diagnosis, and management of orofacial pain.

LATEST DEVELOPMENTS

Published in 2019, the International Classification of Orofacial Pain has become the internationally accepted classification system for primary and secondary facial pain. New discoveries in temporomandibular disorders have demonstrated that they are far more complex than the traditional dental mechanistic point of view. A 2020 consensus report released by the National Academies of Sciences, Engineering, and Medicine entitled "Temporomandibular Disorders: Priorities for Research and Care" highlighted this paradigm shift and its importance for patient care, education, and research.

ESSENTIAL POINTS

Orofacial pain comprises many disorders with different etiologies and pathophysiologies. The subjectivity of the pain experience and the interrelated anatomy and physiology of the craniofacial area add to the complexity of diagnosis when the source and etiology of pain are not clear. As orofacial pain straddles the expertise of multiple disciplines, a multidisciplinary approach combining medication, physical therapy, and procedural and psychological strategies is essential in treating patients with orofacial pain.

Comparison of the Efficacy of Complete Endoscopic and Microscopic Vascular Decompression in the Treatment of Classical Trigeminal Neuralgia

OBJECTIVE

To compare whether there is a difference in the efficacy of complete endoscopic microvascular decompression (EVD) and microscopic microvascular decompression (MVD) in patients with classical trigeminal neuralgia (CTN).

METHODS

From January 2014 to January 2021, 297 CTN patients were assigned to the retrosigmoid approach EVD (138 cases) and the MVD groups (159 cases); to compare whether there are differences in the pain control rate, recurrence, complications of CTN patients between the 2operations, and separately predict the factors related to prognosis of both groups.

RESULTS

There was no significant difference in painless rates at 1, 3, and 5 years after surgery (P = 0.356, P = 0.853, P = 1), and overall incidence of complications (P = 0.058) between the EVD and MVD groups. The EVD group had shorter surgical decompression duration than the MVD group (P < 0.001). The painless rate of patients with vertebrobasilar trigeminal neuralgia in the EVD group was higher than that in the MVD group, but the difference was not statistically significant (90% vs. 61.1%, P = 0.058). The independent risk factors associated with a good prognosis in the EVD group were a shorter course of the disease and severe neurovascular conflict, while severe neurovascular conflict is the only independent risk factor associated with a good prognosis in the MVD group.

CONCLUSIONS

For CTN patients, compared with traditional MVD, EVD is also safe and effective and has the advantage of shorter decompression time.The predictive results of prognostic factors also suggest that CTN patients may benefit more from early surgical treatment.

Repeat percutaneous rhizotomy for trigeminal neuralgia is not associated with an increased risk of postoperative complications

BACKGROUND AND OBJECTIVES

Patients undergoing percutaneous rhizotomy for trigeminal neuralgia (TN) may require several procedures to manage their pain. However, it is not fully understood whether repeat procedures influence postoperative complication rates.

METHODS

We retrospectively reviewed patients undergoing rhizotomy at our institution from 2011 to 2022. Patients were included only if they had no history of prior interventions including microvascular decompression (MVD) or radiosurgery. We collected baseline patient information, pain characteristics, and postoperative complications for each patient. Patients were dichotomized into those undergoing primary rhizotomy versus those undergoing a repeat rhizotomy. Potential drivers of postoperative complications were included in a multivariate logistic regression model.

RESULTS

Of the 1904 cases reviewed, 965 met our inclusion criteria. 392 patients underwent primary rhizotomy, and 573 patients underwent repeat rhizotomies. The repeat rhizotomy group was significantly older, p<0.001. Patients in the repeat rhizotomy group expressed higher frequencies of bilateral pain, p=0.01. Patients in the repeat rhizotomy group demonstrated a significantly higher rate of preoperative numbness and postoperative numbness, p<0.001. There were no significant differences in any of the considered complications between the single rhizotomy and repeat rhizotomy groups. On multivariate logistic regression, repeat rhizotomy did not predict an increased risk of any postoperative complications, p=0.14.

CONCLUSIONS

Patients undergoing repeat rhizotomy may be at risk of postoperative numbness but are not at increased risk for postoperative complications. These results are of use to patients who are poor surgical candidates, and thus may require multiple rhizotomies to effectively manage their pain over time.