Efficacy and Safety of Computed Tomography-Guided Percutaneous Balloon Compression under Local Anesthesia for Recurrent Trigeminal Neuralgia: A Prospective Study.

Purpose: There are several ways to treat trigeminal neuralgia (TN); however, TN may recur after treatment. This study investigated the efficacy and safety of computed tomography (CT)-guided percutaneous balloon compression (PBC) under local anesthesia for treatment of recurrent trigeminal neuralgia. Patients and Methods. This is a prospective and nonrandomized controlled clinical study. Forty-eight patients with classical TN were scheduled to undergo PBC surgery at the pain department of our institution between January 2021 and June 2021. The patients were prospectively divided into an initial onset group, A (21 cases), and a recurrence group, B (27 cases). All surgeries were performed with CT guidance and under local anesthesia. Postoperative complications were also observed. Pain was assessed using the visual analog scale (VAS) and Barrow Neurological Institute (BNI) scale. Efficacy indices were evaluated at 3, 6, 12, and 18 months after surgery. Results: All participants reported complete pain relief at discharge. After 18 months of follow-up, the total effective rate of pain control was 89.5% (group A, 90.5%; group B, 88.8%). There was no significant difference in the BNI scores between the two groups before and after treatment. All patients had hypoesthesia on the affected side, and no severe complications such as diplopia, blindness, intracranial hemorrhage, or intracranial infection occurred. Conclusions: CT-guided PBC under local anesthesia is safe and effective for the treatment of recurrent TN and thus acts as an effective alternative for geriatric patients and those with high-risk factors.

Botulinum toxin-A as a treatment option for refractory idiopathic trigeminal neuralgia of the ophthalmic branch: a case report and literature review.

Trigeminal neuralgia is one of the most common neurological pains affecting the head and neck and is associated with severe, lancinating, electrical pain episodes. The maxillary and mandibular branches are usually affected. The ophthalmic branch is rarely involved and, when present, it requires a comprehensive workup to rule out major conditions. Pharmacotherapy and surgery are the most common treatment options for this condition. Systemic medications may pose a wide range of side effects and effectiveness may decrease over time while surgery has inherent complications. Injectable onabotulinum toxins have been utilized for various applications in medicine and dentistry. There is, however, limited data on their use for the management of refractory trigeminal neuralgia of the ophthalmic branch. We present the case of a 58-year-old male diagnosed with refractory idiopathic trigeminal neuralgia affecting the ophthalmic branch, which was unresponsive to standard care and successfully managed with onabotulinum toxin type A. This treatment should be considered in cases of refractory trigeminal neuralgia prior to surgery. We reviewed the relevant literature concerning the application of Onabotulinum toxin A for managing trigeminal neuralgia of the ophthalmic branch. This case report and review aim to enlighten the application of Onabotulinum toxin A for managing refractory trigeminal neuralgia of the ophthalmic branch. Our case report and review show that Onabotulinum toxin A could be used for managing TN of the ophthalmic branch.

Amaurosis and transient diplopia, a rare complication secondary to mandibular nerve block: A case report.

Ocular complications are one of the rare side effects that can be seen after a mandibular nerve block and have the most dramatic results. Since the mandibular nerve block is mostly performed by dentists, this complication is mostly seen after an intraoral mandibular nerve block. The mandibular nerve is the third division of the trigeminal nerve. It is the most caudal and lateral part of Gasser's ganglion. It arises from the middle cranial fossa through the foramen ovale. In this region, a block method, which is performed by passing through the coronoid process, has been defined. This block, usually made using anatomical markers, is used in the treatment of trigeminal neuralgia. A 42-year-old female patient was admitted to our department for a maxillary and mandibular block with a diagnosis of trigeminal neuralgia. Immediately after the administration of the local anesthetic, the patient described a complete loss of vision. The complaint of vision loss lasted for about 1 minute, after which the patient's complaint of diplopia continued for 2 hours and 10 minutes. This case report presents the ocular complications after a mandibular block applied with the extraoral technique as an unexpected side effect.

Compared to oxcarbazepine and carbamazepine, botulinum toxin type A is a useful therapeutic option for trigeminal neuralgia symptoms: A systematic review.

OBJECTIVES: This review aimed to compare the effectiveness of three treatments: BTX A, CBZ, and OXB, in managing trigeminal neuralgia (TN). MATERIAL AND METHODS: We conducted a thorough search for research articles related to our issue using specific keywords on several databases, including Cochrane Central Register of Controlled Trials, Science Direct, Scopus, PubMed, Elsevier, Springer Journals, Ovid Medline, EBSCO, and Web of Science. Our focus was on publications from 1965 to 2023. RESULTS: We retrieved 46 articles from the search and reviewed them carefully. Out of these, we selected 29 articles that met the inclusion criteria. Among the selected articles, 11 investigated the effects of CBZ and OXB, while 18 explored the impact of BTX A on the improvement of TN symptoms. The response rate ranged between 56% and 90.5% for CBZ and between 90.9% and 94% for OXB. The response rate for BTX A ranged between 51.4% and 100%. All these three treatments had a remarkable effect on the improvement of TN. Importantly, findings highlighted that side effects of CBZ and OXB could lead to treatment discontinuation in some cases, whereas BTX A's side effects have been minimal and less frequent. CONCLUSIONS: Consequently, BTX A emerges as a promising alternative for TN treatment. However, additional clinical trials are necessary to validate this finding, and further research is required to establish a standardized protocol for administering BTX A in TN.

Effects of carbamazepine on BDNF expression in trigeminal ganglia and serum in rats with trigeminal neuralgia. / å¡é©¬è¥¿å¹³å¯¹ä¸‰å‰ç¥žç»ç—›å¤§é¼ ä¸‰å‰ç¥žç»èŠ‚åŠè¡€æ¸ ä¸­BDNF表达变化的影响.

OBJECTIVES: Trigeminal neuralgia (TN) is a severe chronic neuropathic pain that mainly affects the distribution area of the trigeminal nerve with limited treating efficacy. There are numerous treatments for TN, but currently the main clinical approach is to suppress pain by carbamazepine (CBZ). Brain-derived neurotrophic factor (BDNF) is closely related to chronic pain. This study aims to determine the effects of CBZ treatment on BDNF expression in both the trigeminal ganglion (TG) and serum of TN via a chronic constriction injury of the infraorbital nerve (ION-CCI) rat model. METHODS: The ION-CCI models were established in male Sprague-Dawley rats and were randomly divided into a sham group, a TN group, a TN+low-dose CBZ treatment group (TN+20 mg/kg CBZ group), a TN+medium-dose CBZ treatment group (TN+40 mg/kg CBZ group), and a TN+high-dose CBZ treatment group (TN+80 mg/kg CBZ group). The mechanical pain threshold in each group of rats was measured regularly before and after surgery. The expressions of BDNF and tyrosine kinase receptor B (TrkB) mRNA in TGs of rats in different groups were determined by real-time PCR, and the expression of BDNF protein on neurons in TGs was observed by immunofluorescence. Western Blotting was used to detect the protein expression of BDNF, TrkB, extracellular regulated protein kinases (ERK), and phospho-extracellular regulated protein kinases (p-ERK) in TGs of rats in different groups. The expression of BDNF in the serum of rats in different groups was detected by enzyme-linked immunosorbent assay (ELISA). RESULTS: The results of mechanical pain sensitivity showed that there was no significant difference in the mechanical pain threshold in the right facial sensory area of the experimental rats in each group before surgery (all P>0.05). From the 3rd day after operation, the mechanical pain threshold of rats in the TN group was significantly lower than that in the sham group (all P<0.01), and the mechanical pain threshold of rats in the TN+80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 CBZ mg/kg group was higher than that in the TN group (all P<0.05). The BDNF and TrkB mRNA and protein expressions in TGs of rats in the TN group were higher than those in the sham group (all P<0.05), and those in the TN+80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 mg/kg CBZ group were lower than the TN group (all P<0.05). The p-ERK levels in TG of rats in the TN+80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 mg/kg CBZ group were significantly decreased compared with the TN group (all P<0.05). The BDNF and neuron-specific nuclear protein (NeuN) were mainly co-expressed in neuron of TGs in the TN group and they were significantly higher than those in the sham group (all P<0.05). The co-labeled expressions of BDNF and NeuN in TGs of the TN+ 80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 mg/kg CBZ group were lower than those in the TN group (all P<0.05). The results of ELISA showed that the level of BDNF in the serum of the TN group was significantly higher than that in the sham group (P<0.05). The levels of BDNF in the TN+80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 mg/kg CBZ group were lower than those in the TN group (all P<0.05). Spearman correlation analysis showed that the BDNF level in serum was negatively correlated with mechanical pain threshold (r=-0.650, P<0.01). CONCLUSIONS: CBZ treatment can inhibit the expression of BDNF and TrkB in the TGs of TN rats, reduce the level of BDNF in serum of TN rats and the phosphorylation of ERK signaling pathway, so as to inhibit TN. The serum level of BDNF can be considered as an indicator for the diagnosis and prognosis of TN.

Cannabidiol and it fluorinate analog PECS-101 reduces hyperalgesia and allodynia in trigeminal neuralgia via TRPV1 receptors.

Trigeminal neuralgia (TN) is an intense and debilitating orofacial pain. The gold standard treatment for TN is carbamazepine. This antiepileptic drug provides pain relief with limited efficacy and side effects. To study the antinociceptive potential of cannabidiol (CBD) and its fluorinated analog PECS-101 (former HUF-101), we induced unilateral chronic constriction injury of the infraorbital nerve (IoN-CCI) in male Wistar rats. Seven days of treatment with CBD (30 mg/kg), PECS-101 (3, 10, and 30 mg/kg), or carbamazepine (10 and 30 mg/kg) reduced allodynia and hyperalgesia responses. Unlike carbamazepine, CBD and PECS-101 did not impair motor activity. The relief of the hypersensitive reactions has been associated with transient receptor potential vanilloid type 1 (TRPV1) modulation in the trigeminal spinal nucleus. CBD (30 mg/kg) and PECS-101 (10 and 30 mg/kg) reversed the increased expression of TRPV1 induced by IoN-CCI in this nucleus. Using a pharmacological strategy, the combination of the selective TRPV1 antagonist (capsazepine-CPZ - 5 mg/kg) with sub-effective doses of CBD (3 and 10 mg/kg) is also able to reverse the IoN-CCI-induced allodynia and hyperalgesia responses. This effect was accompanied by reduced TRPV1 protein expression in the trigeminal spinal nucleus. Our results suggest that CBD and PECS-101 may benefit trigeminal neuralgia without motor coordination impairments. PECS-101 is more potent against the hypernociceptive and motor impairment induced by TN compared to CBD and carbamazepine. The antinociceptive effect of these cannabinoids is partially mediated by TRPV1 receptors in the caudal part of the trigeminal spinal nucleus, the first central station of orofacial pain processing.

Trigeminal neuralgia and trigeminal neuropathic pain.

It is very important that the dental team are aware of the varied presentations of pain in the mouth, face and other parts of the trigeminal region which are not directly caused by teeth or oral structures. Our understanding of underlying causes in this complex area is evolving. Ultimately, patients who present with what may at first seem to be oral or dental problems will require specialist input in secondary care with potential for use of systemic medications. This article reviews the common non-dental pains encountered in the orofacial region related to dysfunction of the trigeminal nerve.

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

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

Sex differences in carbamazepine effects in a rat model of trigeminal neuropathic pain.

Carbamazepine (CBZ) represents the first-line treatment for trigeminal neuralgia, a condition of facial pain that affects mainly women. The chronic constriction of the infraorbital nerve (CCI-ION) is a widely used model to study this condition, but most studies do not include females. Thus, this study aimed to characterize sensory and affective changes in female rats after CCI-ION and compare the effect of CBZ in both sexes. Mechanical allodynia was assessed 15 days after CCI-ION surgery in rats treated with CBZ (10 and 30 mg/kg, i.p.) or vehicle, together with the open-field test. Independent groups were tested on the Conditioned Place Preference (CPP) paradigm and ultrasonic vocalization (USV) analysis. Blood samples were collected for dosage of the main CBZ metabolite. CBZ at 30 mg/kg impaired locomotion of CCI-ION male and sham and CCI-ION female rats and resulted in significantly higher plasma concentrations of 10-11-EPX-CBZ in the latter. Only male CCI-ION rats showed increased facial grooming which was significantly reduced by CBZ at 10 mg/kg. CBZ at 10 mg/kg significantly reduced mechanical allodynia and induced CPP only in female CCI-ION rats. Also, female CCI-ION showed reduced emission of appetitive USV but did not show anxiety-like behavior. In conclusion, male and female CCI-ION rats presented differences in the expression of the affective-motivational pain component and CBZ was more effective in females than males. Further studies using both sexes in trigeminal neuropathic pain models are warranted for a better understanding of potential differences in the pathophysiological mechanisms and efficacy of pharmacological treatments.

[Pharmacological Treatment of Trigeminal Neuralgia].

Although carbamazepine is the first-line treatment option for trigeminal neuralgia, it may not be sustained long-term. The benefits of carbamazepine are offset by adverse effects that lead to its withdrawal. The alternatives to carbamazepine include gabapentin, pregabalin, and microgabalin. Although used off-label in Japan, baclofen, lamotrigine, intravenous lidocaine, and botulinum toxin type A are also effective. Clinical experience has shown that alternative treatments are less effective than carbamazepine. Therefore, they can be used instead of or in addition to carbamazepine. The adverse effects of drugs include drowsiness, dizziness, rash, bone marrow suppression, and liver dysfunction. Carbamazepine and lamotrigine are particularly likely to cause severe drug eruptions such as Stevens-Johnson syndrome and toxic epidermal necrolysis. Low-dose titration is important to avoid the development of rashes and adverse effects.

Tapentadol helps in trigeminal neuralgia: a case report.

BACKGROUND: Trigeminal neuralgia (TN) usually affects people over 50 years old. TN-related pains are short-lived, and the disease course is characterized by exacerbations and remissions. Sometimes chronic pain develops due to central sensitization. This is the first case report on the effectiveness of tapentadol in pain control in TN. CASE DESCRIPTION: It is an instructive case history demonstrating the high effectiveness of tapentadol in a 55-year-old Caucasian male with severe [Visual Analogue Scale (VAS) 9/10] TN-related pain and a history of ineffective treatment with antiepileptic drugs. The neuralgia had occurred twice a year for the three preceding years, and typically the TN periods lasted 2-3 weeks with complete remissions between. Previously the patient had been treated with antiepileptic drugs (e.g., carbamazepine, phenytoin, clonazepam, gabapentin, and lamotrigine). However, he found all treatments to be ineffective and accompanied by unacceptable somnolence. Thus, a prolonged-release oral tapentadol was proposed at the beginning of the next relapse. After application of tapentadol, the patient reported a significant improvement. The severity of pain declined to VAS 6/10 (2nd day) and 4/10 (3rd day), and the attacks resolved entirely on the fourth day of treatment. He reported no side effects. The drug was discontinued after 14 days. CONCLUSIONS: Despite pain chronification, tapentadol was efficient and well tolerated in TN. Further research is needed to reveal tapentadol's efficacy in neuralgias.

Intranasal CRMP2-Ubc9 inhibitor regulates Na V 1.7 to alleviate trigeminal neuropathic pain.

ABSTRACT: Dysregulation of voltage-gated sodium Na V 1.7 channels in sensory neurons contributes to chronic pain conditions, including trigeminal neuropathic pain. We previously reported that chronic pain results in part from increased SUMOylation of collapsin response mediator protein 2 (CRMP2), leading to an increased CRMP2/Na V 1.7 interaction and increased functional activity of Na V 1.7. Targeting this feed-forward regulation, we developed compound 194 , which inhibits CRMP2 SUMOylation mediated by the SUMO-conjugating enzyme Ubc9. We further demonstrated that 194 effectively reduces the functional activity of Na V 1.7 channels in dorsal root ganglia neurons and alleviated inflammatory and neuropathic pain. Here, we used a comprehensive array of approaches, encompassing biochemical, pharmacological, genetic, electrophysiological, and behavioral analyses, to assess the functional implications of Na V 1.7 regulation by CRMP2 in trigeminal ganglia (TG) neurons. We confirmed the expression of Scn9a , Dpysl2 , and UBE2I within TG neurons. Furthermore, we found an interaction between CRMP2 and Na V 1.7, with CRMP2 being SUMOylated in these sensory ganglia. Disrupting CRMP2 SUMOylation with compound 194 uncoupled the CRMP2/Na V 1.7 interaction, impeded Na V 1.7 diffusion on the plasma membrane, and subsequently diminished Na V 1.7 activity. Compound 194 also led to a reduction in TG neuron excitability. Finally, when intranasally administered to rats with chronic constriction injury of the infraorbital nerve, 194 significantly decreased nociceptive behaviors. Collectively, our findings underscore the critical role of CRMP2 in regulating Na V 1.7 within TG neurons, emphasizing the importance of this indirect modulation in trigeminal neuropathic pain.

Transplantation of olfactory ensheathing cells can alleviate neuroinflammatory responses in rats with trigeminal neuralgia.

Trigeminal neuralgia (TN) is a common form of facial pain, which primarily manifests as severe pain similar to facial acupuncture and electric shock. Olfactory ensheathing cells (OECs) are glial cells with high bioactivity; these cells are essential for the periodic regeneration of the olfactory nerve and have been utilized for the repair of nerve injuries. A member of the P2X receptor family, P2X7R, is an ion channel type receptor that has been confirmed to participate in various pain response processes. In this study, we transplanted OECs into trigeminal nerve-model rats with distal infraorbital nerve ligation to observe the therapeutic effect of transplanted OECs in rats. Additionally, we utilized the P2X7R-specific inhibitor brilliant blue G (BBG) to study the therapeutic mechanisms of cell transplantation. The facial mechanical pain threshold of these rats significantly increased following cell transplantation. The immunohistochemistry, immunoblotting, and RT-qPCR results demonstrated that the levels of P2X7R, (NOD)-like receptor protein-3 (NLRP3), nuclear factor-κB (NF-κB), interleukin (IL)-1ß, and IL-18 in the trigeminal ganglion of rats treated with OEC transplantation or BBG treatment were significantly lower than those in the injured group without treatment. Overall, our results demonstrate that OEC transplantation can alleviate TN in rats, and it can reduce the expression of P2X7R related inflammatory factors in TN rats, reducing neuroinflammatory response in TG.

Microvascular decompression for trigeminal neuralgia: A retrospective analysis of long-term outcomes and prognostic factors / Descompresión microvascular en la neuralgia del trigémino: análisis retrospectivo de los resultados a largo plazo e identificación de factores pronósticos

Introduction: Microvascular decompression is considered to be the most effective and onlyetiological surgical treatment for classical trigeminal neuralgia, relieving the neurovascularcompression found in up to 95% of cases. This study aims to report the long-term outcomesand to identify prognostic factors in a series of patients with trigeminal neuralgia treated bymicrovascular decompression. Methods: A retrospective observational study of 152 consecutive patients operated bymicrovascular decompression with at least six months of follow-up. The surgical results, includ-ing pain relief according to the Barrow Neurological Institute pain scale, complications and themedical treatment during the follow-up period were reviewed. Binary regression analysis wasperformed to identify factors associated with a good long-term outcome. Results: A total of 152 patients with a mean age of 60 years and a mean follow-up of 43 monthswere included. At the final follow-up visit, 83% of the patients had achieved significant reliefof the pain and 63% could reduce the absolute drug doses by 50% or more. The most frequentcomplications were wound infection (4.5%) and CSF fistula (7%). Being over 70 years of age andhaving paroxysmal pain were associated with a long-term pain relief.(AU)

Introducción: La descompresión microvascular se considera el tratamiento quirúrgico etiológico más eficaz de la neuralgia clásica del trigémino, dirigido a aliviar la compresión neurovascular identificada hasta en un 95% de casos. Este estudio tiene como objetivo analizar los resultados quirúrgicos y la evolución a largo plazo de una serie de pacientes con neuralgia del trigémino tratados mediante descompresión microvascular, así como identificar factores pronósticos. Métodos: Estudio observacional retrospectivo de 152 pacientes consecutivos sometidos a descompresión microvascular y con un seguimiento posquirúrgico mínimo de seis meses. Analizamos los resultados quirúrgicos, clasificando el grado de dolor según la escala del Instituto Neurológico de Barrow, las complicaciones y el tratamiento médico requerido durante el período de seguimiento. Realizamos un análisis de regresión binaria para identificar factores asociados con un buen resultado a largo plazo. Resultados: Incluimos 152 pacientes con una edad media de 60 años y un seguimiento medio de 43 meses. En la última visita de seguimiento, el 83% de los pacientes había logrado un alivio significativo del dolor y el 63% pudo reducir la dosis absoluta de fármacos para la neuralgia en un 50% o más. Las complicaciones más frecuentes fueron infección de la herida (4,5%) y fístula de LCR (7%). La edad superior a 70 años y el dolor de predominio paroxístico se asociaron con un mejor pronóstico. Conclusiones: Nuestros resultados apoyan que la descompresión microvascular es una terapia efectiva y segura en pacientes con neuralgia del trigémino. La cirugía temprana puede ser beneficiosa en pacientes refractarios al tratamiento farmacológico.(AU)

The Therapeutic Effect of Botulinum Toxin Type A on Trigeminal Neuralgia: Are There Any Differences between Type 1 versus Type 2 Trigeminal Neuralgia?

BACKGROUND: Botulinum toxin type A is an effective treatment for trigeminal neuralgia. Moreover, its efficacy in type 2 trigeminal neuralgia and comparative studies between type 1 and type 2 trigeminal neuralgia (TN) still need to be improved. METHODS: We treated 40 TN patients with onabotulinumtoxinA; 18 had type 1 TN, and 22 had type 2 TN. We compared the baseline pain score with the Visual Analogue Scale (VAS) and paroxysm frequency (number per week) at the baseline with those obtained at 1-month and 3-month follow-ups. Nonetheless, we compared the baseline Penn Facial Pain Scale with the scores obtained at the 1-month follow-up. RESULTS: BoNT/A effectively reduced pain intensity and frequency at the 1-month and 3-month follow-ups. Moreover, the type 1 TN and type 2 TN groups had baseline pain scores of 7.8 ± 1.65 and 8.4 ± 1.1, respectively. Pain significantly improved (p < 0.001) in both groups to 3.1 ± 2.3 (type 1 TN) and 3.5 ± 2.3 (type 2 TN) at the 1-month follow-up and to 3.2 ± 2.5 (type 1 TN) and 3.6 ± 2.5 (type 2 TN) at the 3-month follow-up. There was no difference between the two groups (p 0.345). The baseline paroxysm frequencies (number per week) were 86.7 ± 69.3 and 88.9 ± 62.2 for the type 1 and type 2 TN groups, respectively; they were significantly reduced in both groups at the 1-month and 3-month follow-ups without significant differences between the two groups (p 0.902). The Pain Facial Pain Scale improved at the 1-month follow-up, and no significant differences were found between the two groups. There was a strong correlation between background pain and paroxysm pain intensity (r 0.8, p < 0.001). CONCLUSIONS: Botulinum toxin type A effectively reduced the pain, paroxysm frequency, and PFPS scores of type 1 and type 2 trigeminal neuralgia patients without statistically significant differences. Facial asymmetry was the only adverse event.

BMP7 alleviates trigeminal neuralgia by reducing oligodendrocyte apoptosis and demyelination.

BACKGROUND: BMP7 has been shown to have neuroprotective effects and to alleviate demyelination. However, its role in trigeminal neuralgia (TN) has not been well investigated. The current study aims to determine whether BMP7 plays a role in demyelination, its effects on pain behaviors and mechanism of action in rats with TN. METHODS: We used an infraorbital-nerve chronic-constriction injury (ION-CCI) to establish a rat model of TN. Adeno-associated viruses (AAVs) were injected into the rats to upregulate or downregulate BMP7. The mechanical withdrawal thresholds (MWT) of the injured rats were detected using Von Frey filaments. The changes in expression levels of BMP7 and oligodendrocyte (OL) markers were examined by western blotting, quantitative real-time PCR, immunofluorescence, and transmission electron microscopy. RESULTS: The ION-CCI induced mechanical allodynia, demyelination, and loss of OLs with a reduction of BMP7. Short-hairpin RNA (shRNA)-BMP7 that inhibited BMP7 expression also caused mechanical allodynia, demyelination, and loss of OLs, and its mechanism may be OL apoptosis. Overexpressing BMP7 in the trigeminal spinal subnucleus caudalis(VC) with AAV-BMP7 relieved all three phenotypes induced by the CCI, and its mechanism may be alleviating OLs apoptosis. Two signal pathways associated with apoptosis, STAT3 and p65, were significantly downregulated in the VC after CCI and rescued by BMP7 overexpression. CONCLUSION: BMP7 can alleviate TN by reducing OLs apoptosis and subsequent demyelination. The mechanism behind this protection could be BMP7-mediated activation of the STAT3 and NF-κB/p65 signaling pathway and subsequent decrease in OL apoptosis. Importantly, our study presents clear evidence in support of BMP7 as a possible therapeutic target for the treatment of TN.

GFAP-NpHR mediated optogenetic inhibition of trigeminal nucleus caudalis attenuates hypersensitive behaviors and thalamic discharge attributed to infraorbital nerve constriction injury.

The significance of hyperactive astrocytes in neuropathic pain is crucial. However, the association between medullary astrocytes and trigeminal neuralgia (TN)-related pain processing is unclear. Here, we examined how optogenetic inhibition of medullary astrocytes in the trigeminal nucleus caudalis (TNC) regulates pain hypersensitivity in an infraorbital nerve (ION) constricted TN model. We used adult Sprague Dawley rats subjected to infraorbital nerve (ION) constriction to mimic TN symptoms, with naive and sham rats serving as controls. For in vivo optogenetic manipulations, rats stereotaxically received AAV8-GFAP-eNpHR3.0-mCherry or AAV8-GFAP-mCherry at the trigeminal nucleus caudalis (TNC). Open field, von Frey, air puff, and acetone tests measured pain behavioral flexibility. In vivo thalamic recordings were obtained simultaneously with optogenetic manipulation in the TNC. Orofacial hyperalgesia and thalamic hyperexcitability were both accompanied by medullary astrocyte hyperactivity, marked by upregulated GFAP. The yellow laser-driven inhibition of TNC astrocytes markedly improved behavioral responses and regulated thalamic neuronal responses. Halorhodopsin-mediated inhibition in medullary astrocytes may modify the nociceptive input transmitted through the trigeminothalamic tract and pain perception. Taken together, these findings imply that this subpopulation in the TNC and its thalamic connections play a significant role in regulating the trigeminal pain circuitry, which might aid in the identification of new therapeutic measures in TN management.

Single OnabotulinumtoxinA Session Add-On to Carbamazepine or Oxcarbazepine in Treatment-Refractory Trigeminal Neuralgia: A Case Series with 24-Week Follow Up.

We sought to assess the efficacy of combining onabotulinumtoxinA (BoNTA) as add-on therapy to carbamazepine or oxcarbazepine in treatment-refractory patients with trigeminal neuralgia (TGN) who failed to respond (less than 30% response rate) to adequate monotherapy. We conducted a retrospective study on 15 patients with a definite diagnosis of TGN, according to the established criteria, and underwent BoNTA as part of their treatment plan. A single BoNTA session was administered subcutaneously, according to patients' perceived zone of pain, at different dosages ranging from 30 to 200 units (mean ± standard deviation: 87.3 ± 39.2). All patients (15/15; 100%) reported large reductions in the severity of their TGN-related neuropathic pain. The mean pain score on the VAS scale significantly decreased from 9.3 ± 1.1 to 3.7 ± 1.2 at 2 weeks after injecting BoNTA (p < 0.001) and remained stable at 4 and 24 weeks post-injection. Regarding the impact of BoNTA on patients' health-related quality of life, there were significant improvements in both the physical and mental health domains (p < 0.05) of SF-36 tool. BoNTA may be a safe and effective treatment option for patients with refractory TGN when added on to carbamazepine or oxcarbazepine. The use of a single BoNTA session for TGN treatment may be an alternative to surgical interventions and as add-on treatment to oral medications, providing patients with a minimally invasive, effective, safe and well-tolerated option.

Is Botulinum Toxin Effective in Treating Orofacial Neuropathic Pain Disorders? A Systematic Review.

BACKGROUND: The aim of this paper is to provide a systematic review of the literature regarding the clinical use of botulinum toxin (BTX) to treat various orofacial neuropathic pain disorders (NP). METHODS: A comprehensive literature search was conducted using Medline, Web of Science, and the Cochrane Library databases. Only randomized clinical trials (RCT) published between 2003 and the end of June 2023, investigating the use of BTX to treat NP, were selected. PICO guidelines were used to select and tabulate the articles. RESULTS: A total of 6 RCTs were selected. Five articles used BTX injections to treat classical trigeminal neuralgia, and one to treat post-herpetic neuralgia. A total of 795 patients received BTX injections. The selected studies utilised different doses and methods of injections and doses. All the selected studies concluded superiority of BTX injections over placebo for reducing pain levels, and 5 out 6 of them highlighted an improvement in the patient's quality of life. Most of the studies reported transient and mild side effects. CONCLUSION: There is evidence of the efficacy of BTX injections in orofacial pain management. However, improved study protocols are required to provide direction for the clinical use of BTX to treat various orofacial neuropathic pain disorders.

Outcomes and Predictors of Response to Pregabalin for the Treatment of Post-Traumatic Trigeminal Neuropathic Pain Following Neuroablative Procedures: A Retrospective Observational Study.

BACKGROUND: Post-traumatic trigeminal neuropathic pain (PTNP) following trigeminal neuralgia (TN)-related neuroablative procedures is relatively rare. Due to the fear of debilitating complications, its treatment has been generally suboptimal. Pregabalin (PGB) has been reported to relieve neuropathic pain. However, the potential role of PGB and the predictors of response of PGB use as a strategy in the treatment of PTNP following TN-related neuroablative procedures have not been identified yet. OBJECTIVES: To report the efficacy and safety of PGB and the identification of predictors of PGB for PTNP following TN-related neuroablative procedures. STUDY DESIGN: Monocentric, retrospective, observational study. SETTING: This study consecutively enrolled patients with PTNP following TN-related neuroablative procedures who were prescribed PGB at Beijing Tiantan Hospital. METHODS: From January 2018 to June 2022, a total of 112 patients were included in this study, of whom 10 were excluded because of incomplete follow-up data and side effects immediately after taking PGB. Final analysis included 102 patients. Demographic data, pain-related baseline data, efficacy of patients with PTNP after one month of PGB evaluated by the Barrow Neurological Institute (BNI) scores for pain, and side effects of PGB were extracted and analyzed. The predictors of pain-relieving effects of PGB were identified by logistic regression analysis. RESULTS: Within one month after the use of PGB alone, 29 out of the 102 (28.4%) patients achieved pain relief with a significant reduction in the BNI scores (P < 0.01). All of the 73 patients who did not respond to PGB monotherapy either switched to other medications (n = 8) or combined additional oral medications to the existing PGB therapy (n = 65). The main side effect of PGB in our study was dizziness. Binary logistic regression analysis showed that longer disease durations (Adjusted odds ratio [OR] = 0.55, 95% confidence interval [CI] 0.43 to 0.72, P = 0.000) and higher Hospital Anxiety and Depression Scale (HADS) scores (Adjusted OR = 0.29, 95% CI 0.10 to 0.87, P = 0.022) were poor predictors of response to PGB. LIMITATIONS: This was a retrospective observational study. Long-term efficacy and safety of PGB in the treatment of PTNP patients were not evaluated. CONCLUSIONS: This study confirms that PGB monotherapy is not a very effective treatment for PTNP following TN-related neuroablative procedures. PGB was more beneficial in patients with shorter disease durations and lower HADS scores. KEY WORDS: Post-traumatic trigeminal neuropathic pain, efficacy, safety, predictor of response, pregabalin.