Trigeminal Neuralgia

Trigeminal neuralgia with rare solitary pontine lesion: A case report and literature review

Trigeminal neuralgia (TN) associated with brainstem lesions as revealed by Magnetic resonance imaging (MRI), is a rare condition. The MRI often shows a distinctive single pontine in cases of TN (SPL-TN). While the significance of this MRI finding remains unclear, various case reports suggest a potential link to chronic injury in the pontine pathways of the trigeminal nerve. In this report, we present the case of a 42-year-old female who was referred for TN that is refractory to medical treatment with an ipsilateral MRI lesion over the pons who had an excellent response to a trigeminal nerve bock, shedding light on the intriguing interplay between TN and pontine lesions.

An update on pharmacotherapy for trigeminal neuralgia

INTRODUCTION

Trigeminal neuralgia is a rare condition that can be effectively treated by carbamazepine or oxcarbazepine but these older drugs are associated with dose-dependent and potentially treatment-limiting adverse effects. Third-generation anticonvulsants, new calcitonin gene-related peptide blockers for migraine, and older drugs such as ketamine and cannabinoids may be promising adjuvants or monotherapeutic options.

AREAS COVERED

The new drugs, their presumed mechanisms of action, safety and efficacy are discussed herein. There is a paucity of robust clinical evidence in support of these drugs for trigeminal neuralgia. New migraine agents are considered as well although migraines and trigeminal neuralgia are distinct, albeit similar, conditions. No new drugs have been released to market in recent years with the specific indication of trigeminal neuralgia.

EXPERT OPINION

In real-world clinical practice, about half of trigeminal neuralgia patients take more than one agent for prevention and combination therapy may be the optimal approach. Combination therapy might allow for lower doses of carbamazepine or oxcarbazepine, thus reducing the number and severity of potential adverse events but the potential for pharmacokinetic drug-drug interactions must be considered. Drug therapy for trigeminal neuralgia involves acute or abortive treatments, often administered in hospital versus long-term preventive therapy, usually involving oral agents.

Enkephalins and Pain Modulation: Mechanisms of Action and Therapeutic Perspectives

Enkephalins, a subclass of endogenous opioid peptides, play a pivotal role in pain modulation. Enkephalins primarily exert their effects through opioid receptors located widely throughout both the central and peripheral nervous systems. This review will explore the mechanisms by which enkephalins produce analgesia, emotional regulation, neuroprotection, and other physiological effects. Furthermore, this review will analyze the involvement of enkephalins in the modulation of different pathologies characterized by severe pain. Understanding the complex role of enkephalins in pain processing provides valuable insight into potential therapeutic strategies for managing pain disorders.

Efficacy and safety of microvascular decompression with or without partial sensory rhizotomy: a comprehensive meta-analysis and systematic review in treating trigeminal neuralgia

Classical trigeminal neuralgia (TN), caused by vascular compression of the nerve root, is a severe cause of pain with a considerable impact on a patient's quality of life. While microvascular decompression (MVD) has lower recurrence rates when compared with partial sensory rhizotomy (PSR) alone, refractoriness can still be as high as 47%. We aimed to assess the efficacy and safety profile of MVD + PSR when compared to standalone MVD for TN. We searched Medline, Embase, and Web of Science following PRISMA guidelines. Eligible studies included those with ≥ 4 patients, in English, published between January 1980 and December 2023, comparing MVD vs. MVD + PSR for TN. Endpoints were pain cure, immediate post-operative pain improvement, long-term effectiveness, long-term recurrence, and complications (facial numbness, hearing loss, and intracranial bleeding). We pooled odds ratios (OR) with 95% confidence intervals with a random-effects model. I2 was used to assess heterogeneity, and sensitivity and Baujat analysis were conducted to address high heterogeneity. Eight studies were included, comprising a total of 1,338 patients, of whom 1,011 were treated with MVD and 327 with MVD + PSR. Pain cure analysis revealed a lower likelihood of pain cure in patients treated with MVD when compared to patients treated with MVD + PSR (OR = 0.30, 95% CI: 0.13 to 0.72). Immediate postoperative pain improvement assessment revealed a lower likelihood of improvement in the MVD group when compared with the MVD + PSR group (OR = 0.31, 95% CI: 0.10 to 0.95). Facial numbness assessment revealed a lower likelihood of occurrence in MVD alone when compared to MVD + PSR (OR = 0.08, 95% CI: 0.04 to 0.15). Long-term effectiveness, long-term recurrence, hearing loss, and intracranial bleeding analyses revealed no difference between both approaches. Our meta-analysis identified that MVD + PSR was superior to MVD for pain cure and immediate postoperative pain improvement for treating TN. However, MVD + PSR demonstrated a higher likelihood of facial numbness complications. Furthermore, identified that hearing loss and intracranial bleeding complications appear comparable between the two treatments, and no difference between long-term effectiveness and recurrence.

Challenges in Optimizing Nanoplatforms Used for Local and Systemic Delivery in the Oral Cavity

In this study, we focused on innovative approaches to improve drug administration in oral pathology, especially by transmucosal and transdermal pathways. These improvements refer to the type of microneedles used (proposing needles in the saw), to the use of certain enhancers such as essential oils (which, besides the amplifier action, also have intrinsic actions on oral health), to associations of active substances with synergistic action, as well as the use of copolymeric membranes, cemented directly on the tooth. We also propose a review of the principles of release at the level of the oral mucosa and of the main release systems used in oral pathology. Controlled failure systems applicable in oral pathology include the following: fast dissolving films, mucoadhesive tablets, hydrogels, intraoral mucoadhesive films, composite wafers, and smart drugs. The novelty elements brought by this paper refer to the possibilities of optimizing the localized drug delivery system in osteoarthritis of the temporomandibular joint, neuropathic pain, oral cancer, periodontitis, and pericoronitis, as well as in maintaining oral health. We would like to mention the possibility of incorporating natural products into the controlled failure systems used in oral pathology, paying special attention to essential oils.

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.

A novel indicator to predict the outcome of percutaneous stereotactic radiofrequency rhizotomy for trigeminal neuralgia patients: diffusivity metrics of MR-DTI

Magnetic resonance-diffusion tensor imaging (MR-DTI) has been used in the microvascular decompression and gamma knife radiosurgery in trigeminal neuralgia (TN) patients; however, use of percutaneous stereotactic radiofrequency rhizotomy (PSR) to target an abnormal trigeminal ganglion (ab-TG) is unreported. Fractional anisotropy (FA), mean and radial diffusivity (MD and RD, respectively), and axial diffusivity (AD) of the trigeminal nerve (CNV) were measured in 20 TN patients and 40 healthy control participants immediately post PSR, at 6-months, and at 1 year. Longitudinal alteration of the diffusivity metrics and any correlation with treatment effects, or prognoses, were analyzed. In the TN group, either low FA (value < 0.30) or a decreased range compared to the adjacent FA (dFA) > 17% defined an ab-TG. Two-to-three days post PSR, all 15 patients reported decreased pain scores with increased FA at the ab-TG (P < 0.001), but decreased MD and RD (P < 0.01 each). Treatment remained effective in 10 of 14 patients (71.4%) and 8 of 12 patients (66.7%) at the 6-month and 1-year follow-ups, respectively. In patients with ab-TGs, there was a significant difference in treatment outcomes between patients with low FA values (9 of 10; 90%) and patients with dFA (2 of 5; 40%) (P < 0.05). MR-DTI with diffusivity metrics correlated microstructural CNV abnormalities with PSR outcomes. Of all the diffusivity metrics, FA could be considered a novel objective quantitative indicator of treatment effects and a potential indicator of PSR effectiveness in TN patients.

Mental Nerve Neurectomy: A Comparison of Titanium Screw Versus Gutta-Percha Oburation of the Mental Foramen

OBJECTIVE

 This study aims to compare the two mental foramen obturating techniques in parameters like operator's ease, postoperative displacement of obturation material, and remission of pain after peripheral neurectomy in patients with trigeminal neuralgia.

STUDY DESIGN

 This study adopts a single-centered comparative analytical approach.

PLACE AND DURATION OF STUDY

This study was performed in the Department of Oral and Maxillofacial Surgery, Armed Forces Institute of Dentistry (AFID), from October 1, 2023, to February 10, 2024.

METHODOLOGY

Sixty patients fulfilling the inclusion criteria were included and divided into two groups (30 each), and peripheral neurectomy was performed under local anesthesia. In one group, gutta-percha sticks were used to obturate the foramina, and in the other group, titanium screws were used. Postoperatively, the operator's ease, postoperative displacement, and relapse of pain were recorded.

RESULTS

 Titanium screws were easy to handle, and there was no relapse of pain because of no displacement postoperatively when compared with gutta-percha sticks, which were hard to manipulate and showed a relapse of pain.

CONCLUSIONS

 Titanium screws have better postoperative outcomes when compared with gutta-percha sticks in terms of the operator's ease, relapse of pain, and postoperative displacement.

miRNA contributes to neuropathic pains

Neuropathic pain (NP) is a kind of chronic pain caused by direct injury to the peripheral or central nervous system (CNS). microRNAs (miRNAs) are small noncoding RNAs that mostly interact with the 3 untranslated region of messenger RNAs (mRNAs) to regulate the expression of multiple genes. NP is characterized by changes in the expression of receptors and mediators, and there is evidence that miRNAs may contribute to some of these alterations. In this review, we aimed to fully comprehend the connection between NP and miRNA; and also, to establish a link between neurology, biology, and dentistry. Studies have shown that targeting miRNAs may be an effective therapeutic strategy for the treatment of chronic pain and potential target for the prevention of NP.

Percutaneous ballon compression for recurrent TN -a retrospective study of 33 cases

Objective

To investigate the clinical efficacy of percutaneous microballoon compression in the treatment of recurrent TN.

Methods

This retrospective study included 33 patients who underwent percutaneous microballoon compression for the treatment of recurrent TN from March 2019 to May 2022. Postoperative pain recurrence and facial numbness were assessed according to the Barrow Neurological Institute (BNI) pain score. Patients' anxiety and sleep status during follow-up were assessed according to the Self-rating Anxiety Scale (SAS) and Pittsburgh Sleep Quality Index (PSQI).

Results

All patients (33 cases) were followed up for 12-38 months, with an average follow-up time of 23 months. On postoperative day 1, 31 patients (93.9%) reported no pain, and 2 patients were given drug treatment for pain relief, The total efficacy was 93.9%. Moreover, 2 patients (6.1%) reported significant pain relief 2 weeks postoperatively. There are many complications during and after PBC. The incidence of the trigeminocardiac reflex (TCR) during surgery was 100%, and the incidence of facial numbness, masseter muscle weakness, labial herpes and headache was 97, 60.6, 12.1 and 3%. No patient experienced severe facial numbness, hearing impairment, diplopia, injury to cranial nerves, Meningitis, intracranial haemorrhage or keratitis. 1 patient had recurrence of pain at 6 months post-op, which was relieved by oral medication. 81.8% suffered from anxiety and 54.5% had poor sleep quality before surgery. After the period of PBC, SAS and PSQI scores decreased continuously. There were significant improvements in anxiety and sleep status postoperatively compared with preoperatively.

Conclusion

PBC is a safe and effective option for the treatment of recurrent TN. The arduous and demanding nature of the clinical course subjects the patient to severe pain, mental, and physical stress. Thankfully, it significantly improves the symptoms of anxiety, depression, and sleep quality.

Effectiveness of percutaneous balloon compression (PBC) in improving physical function and quality of life in trigeminal neuralgia: a retrospective study

OBJECTIVE

To evaluate the effectiveness of percutaneous balloon compression (PBC) in treating trigeminal neuralgia (TN) and determine improvements in quality of life (QoL) and daily functional status.

METHODS

Data from primary TN (pTN) patients treated with PBC from December 2018 to April 2021 were retrospectively analyzed. Short-Form 36 (SF-36) Health Survey and Functional Independence Measure (FIM) assessments were used to evaluate patients' QoL and physical function every 6 months after surgery, and facial pain was evaluated every 3 to 6 months post-surgery.

RESULTS

A total of 80 pTN patients were enrolled for analysis. The Barrow Neurological Institute (BNI) scores of I-II were achieved in 67 (83.8%) patients immediately after the surgery. The estimated rates of BNI I-II pain relief at one, two, and three years were 94.2%, 87.6%, and 83.2%, respectively. All aspects of the SF-36 questionnaire were significantly improved after the PBC, especially in terms of role physical (RP), bodily pain (BP), and social functioning (SF). Patients' functional outcomes measured by FIM at the 6-month follow-up examination were 108.6 ± 9.9, which was significantly improved compared with the pretreatment scores (90.8 ± 12.7). There was no difference between the severity of facial numbness in FIM and any item of the SF-36 except RP (P = 0.004) at 6 months after surgery. There was also no difference in SF-36 and FIM between patients with or without facial hyperalgesia.

CONCLUSIONS

PBC can produce long-term and stable pain relief and significantly improve the patient's QoL and physical function. However, further well-designed, high-level, evidence-based studies are needed to precisely assess the efficacy of PBC for pTN patients.

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.

Local Ulceration following Peripheral Neurolysis with Absolute Alcohol in Patients with Drug-Refractory Trigeminal Neuralgia: A Series of Four Cases

A significant number of patients with trigeminal neuralgia (TGN) are refractory to first-line drugs and require interruption of the pain pathway by various percutaneous procedures. One such percutaneous technique involves an injection of absolute alcohol (AA) into the peripheral branches of the trigeminal nerve. This procedure is useful in elderly and medically compromised drug-refractory cases of TGN who are not interested in undergoing open neurosurgery. Peripheral neurolysis with AA is easy, quick, and safe. It may be carried out in the outpatient department; however, its use is not free from complications. Here, we report four such patients who were complicated with local necrosis and ulceration following administration of AA. The most probable attributable etiologies are sympathetic nerve involvement, intravascular injection of alcohol, vascular spasm of the terminal arteries, distal micro-emboli effect, and faulty technique, including repeated injections.

Preoperative Characteristics and Postoperative Pain Outcomes in Trigeminal Neuralgia With Concomitant Autoimmune Disease

BACKGROUND AND OBJECTIVES

Although the association between multiple sclerosis and trigeminal neuralgia (TN) is well established, little is known about TN pain characteristics and postoperative pain outcomes after microvascular decompression (MVD) in patients with TN and other autoimmune diseases. In this study, we aim to describe presenting characteristics and postoperative outcomes in patients with concomitant TN and autoimmune disease who underwent an MVD.

METHODS

A retrospective review of all patients who underwent an MVD at our institution between 2007 and 2020 was conducted. The presence and type of autoimmune disease were recorded for each patient. Patient demographics, comorbidities, clinical characteristics, postoperative Barrow Neurological Institute (BNI) pain and numbness scores, and recurrence data were compared between groups.

RESULTS

Of the 885 patients with TN identified, 32 (3.6%) were found to have concomitant autoimmune disease. Type 2 TN was more common in the autoimmune cohort ( P = .01). On multivariate analysis, concomitant autoimmune disease, younger age, and female sex were found to be significantly associated with higher postoperative BNI score ( P = .04, <0.001, and <0.001, respectively). In addition, patients with autoimmune disease were more likely to experience significant pain recurrence ( P = .009) and had shorter time to recurrence on Kaplan-Meier analysis ( P = .047), although this relationship was attenuated on multivariate Cox proportional hazards regression.

CONCLUSION

Patients with concomitant TN and autoimmune disease were more likely to have Type 2 TN, had worse postoperative BNI pain scores at the final follow-up after MVD, and were more likely to experience recurrent pain than patients with TN alone. These findings may influence postoperative pain management decisions for these patients and support a possible role for neuroinflammation in TN pain.

Retreatment of Classical Tic Douloureux With Stereotactic Radiosurgery: A Scoping Review

Stereotactic radiosurgery (SRS), also known as gamma knife surgery (GKS), is a noninvasive procedure for treating tic douloureux (TD) or trigeminal neuralgia (TN). Due to a lack of sufficient evidence regarding the indication of SRS for the treatment of recurrent TD, the present scoping review was conducted to assess the effectiveness of repeated SRS procedures for managing recurrent TD. The literature search was performed from January 2012 to December 2022 on the PubMed, Scopus, and Web of Science databases. Of the 215 initial results obtained, 10 articles were finally selected for the review. Three studies used the SRS procedure for the third time in patients with recurrent TD. All studies were retrospective, with a mean maximal dose of 70-90 Gy and a cumulative dose of 120-180 Gy for two SRS treatments and 150-270 Gy for three SRS treatments. The target zone for irradiation was the retrogasserian zone (RGZ). Repeat SRS procedures led to pain relief in 80-90% of patients within one to four months and excellent pain relief in 50-90% of patients. Pain recurrence was noticed after one year in 20-40% of patients. Postoperative complications, such as trigeminal nerve deficits, facial numbness, and mild corneal dryness, were noted in the studies. The review concluded that repeat SRS is an effective and relatively safe procedure for pain management in patients with recurrent TD.

Efficacy of transcutaneous electrical nerve stimulation (TENS) in the management of trigeminal neuralgia: A systematic review and meta-analysis

Background

Trigeminal Neuralgia is one of the most painful disorders known to man. So making patient pain free and to achieve a better quality of life in TN patients is one of the biggest challenge. Non-invasive procedures like Transcutaneous electrical nerve stimulation (TENS) have been tried clinically for Trigeminal neuralgia. Aim: The systematic review and meta-analysis aimed to compare and evaluate the efficacy of transcutaneous electric nerve stimulation in the management of trigeminal neuralgia. The present review has been registered with PROSPERO - An international prospective register of systematic review CRD42021254136.

Material and Methods

An electronic search was done in PubMed, Cochrane Library, Science Direct, Google Scholar, EBSCOHOST. The assessments of articles were done using selection criteria and PRISMA guidelines Only prospective clinical trials like Randomized clinical trials (RCTs) and clinical trials were included in this review. A total of three studies were included in the meta -analysis.

Results

The proportion of total number of patients after TENS therapy across studies with p-value < 0.0001 for each which showed statistically significance. The overall difference in two groups was significant with standardize mean difference of 3.03 [95% CI: 2.50, 3.56].

Conclusions

TENS can be an effective treatment modality for trigeminal neuralgia in reducing the pain intensity with no reported side effects for patients with trigeminal neuralgia alone or even in combination with other first line drugs. Key words:TENS, TN, TENS, TN, Transcutaneous electrical nerve stimulation.

Efficacy and safety of computed tomography-guided percutaneous balloon compression for trigeminal neuralgia secondary to vertebrobasilar dolichoectasia

Percutaneous balloon compression (PBC) of Gasserian ganglion has been popularly used to treat trigeminal neuralgia (TN), one of the most painful syndromes in human experience. Vertebrobasilar dolichoectasia (VBD) is a rare cause of TN and remains challenging to treat. To our knowledge, no study has reported the therapeutic outcome of PBC for VBD-related TN (VBD-TN). In this retrospective study, we collected and analyzed the medical records of all patients undergoing PBC procedure for VBD-TN under the guidance of CT plus three-dimensional reconstruction at the Pain Management Center of Beijing Tiantan Hospital from January 2017 to December 2022. All 23 patients (15 men and 8 women) had a substantial pain relief as modified Barrow Neurological Institute (BNI) I-IIIb immediately after procedure. The follow-up duration ranged from 2 to 63 months, and at the last follow-up visit, only 3 patients (13%) relapsed (BNI IV-V). The cumulative recurrence-free survival was 95%, 87%, and 74% within 1, 3, and 5 years, respectively. Patients' reported satisfactory rate was 100% as Likert scale 4-5 throughout the whole follow-up period, with no severe complications occurring. Our data revealed promising efficacy and safety of PBC procedure for treatment of VBD-TN, thus suggesting a valuable option for pain control in these rare cases of TN. However, there has been no supporting evidence that PBC treatment is a preferred option to other treatments.

A Rare Case of Trigeminal Neuralgia Caused by an Aneurysmal Bone Cyst in the Temporal Bone

Trigeminal neuralgia is a rare and debilitating condition characterized by severe facial pain, often caused by the compression or irritation of the trigeminal nerve. Although trigeminal neuralgia caused by petrous bone lesions is uncommon, it can significantly impact a patient's quality of life. In this case report, we describe a 40-year-old female with a five-year history of severe facial pain diagnosed as trigeminal neuralgia. Imaging revealed an aneurysmal bone cyst in the petrous part of the left temporal bone, located near the trigeminal nerve's root entry zone. The patient underwent a successful left retrosigmoid craniotomy with the resection of the lesion, resulting in a significant improvement in her symptoms. At the six-month follow-up, the patient reported no recurrence of her symptoms and a considerable improvement in her quality of life. Although trigeminal neuralgia caused by an aneurysmal bone cyst in the left temporal bone is rare, surgery is the most effective treatment. Long-term outcomes are generally favorable with close follow-up. This case report highlights the importance of early diagnosis and timely surgical intervention in the management of this debilitating condition.

Endoscopically-Assisted Percutaneous Trigeminal Rhizotomy for Trigeminal Neuralgia: A Cadaveric Feasibility Study

Objective Trigeminal neuralgia (TN) is a debilitating syndrome characterized by paroxysmal facial pain in one or more divisions of the trigeminal nerve. The etiology and treatment paradigms are still controversial. The endoscopically-assisted procedure has not yet been described in percutaneous procedures for TN. The aim of this study was to assess the utility and feasibility of endoscopic-assisted percutaneous approaches for trigeminal rhizotomy in TN.

Methods This study comprised eight cadaveric sides heads that underwent an endoscopically assisted percutaneous approach using Hakanson's anterior puncture method for targeting the foramen ovale.

Results V3 exiting the foramen ovale was easily visualized with the endoscope on all sides. While approaching the foramen ovale, distal branches of V3 such as the lingual and inferior alveolar nerves were first identified as they traveled between the medial and lateral pterygoid muscles. These branches were then traced proximally to the V3 trunk deep to the lateral pterygoid. Large arteries and veins were easily visualized and avoided in the trajectory to the foramen ovale. No gross injury to any neurovascular structure along the course of the needle insertion was identified.

Conclusion We found that endoscopic-assisted percutaneous approach to the foramen ovale is feasible and allows for accurate canalization and anatomical identification of the precise location for rhizotomy under direct visualization. Such a procedure, after it is confirmed in patients, could offer a new technique for reducing unsuccessful canalization and could improve outcomes.

Internal neurolysis versus intraoperative glycerin rhizotomy for trigeminal neuralgia

OBJECTIVE

Internal neurolysis (IN) and intraoperative glycerin rhizotomy (ioGR) are emerging surgical options for patients with trigeminal neuralgia without neurovascular contact. The objective of this study was to compare the neurological outcomes of patients who underwent IN with those of patients who underwent ioGR.

METHODS

The authors retrospectively reviewed all patients who underwent IN or ioGR for trigeminal neuralgia at our institution. Patient demographic characteristics and immediate postoperative outcomes, as well as long-term neurological outcomes, were compared.

RESULTS

Of 1044 patients who underwent open surgical treatment for trigeminal neuralgia, 56 patients underwent IN and 91 underwent ioGR. Of these 147 patients, 37 had no evidence of intraoperative neurovascular conflict. All patients who underwent IN and 96.7% of patients who underwent ioGR had immediate postoperative pain relief. At last follow-up, patients who underwent IN had lower Barrow Neurological Institute (BNI) pain intensity scores (p = 0.05), better BNI facial numbness scores (p < 0.01), and a greater degree of pain improvement (p = 0.05) compared with those who underwent ioGR. Patients who underwent IN also had significantly lower rates of symptomatic pain recurrence (p < 0.01) at last follow-up over an average of 9.5 months.

CONCLUSIONS

IN appears to provide patients with a greater degree of pain relief, lower rates of facial numbness, and lower rates of pain recurrence compared with ioGR. Future prospective studies will better characterize long-term pain recurrence and outcomes.

Radiofrequency Ablation of Gasserian Ganglion in Trigeminal Neuralgia With Multiple Sclerosis: A Rare Clinical Case

In rare instances, the extremely painful disorder trigeminal neuralgia (TN) may develop as a result of multiple sclerosis (MS). In this article, we will be discussing the case of a 56-year-old female with TN. Antidepressants and analgesics can lessen the pain, although they were not very effective, and higher doses led to greater drowsiness and a poorer quality of life. Radiofrequency ablation helped this patient significantly lower the pain and led to an improved lifestyle. This case presents right-side radiofrequency ablation of Gasserian ganglion in a patient with unilateral TN with MS.

High-Dose Frameless Stereotactic Radiosurgery for Trigeminal Neuralgia: A Single-Institution Experience and Systematic Review

OBJECTIVE

Stereotactic radiosurgery is an effective treatment option for trigeminal neuralgia (TN), with frameless stereotactic radiosurgery (fSRS) allowing for a less invasive experience. A single-institutional series and systematic review of the literature were performed for cases of TN treated with fSRS.

METHODS

Patients at our institution with TN that were treated with fSRS from the years 2012-2021 were included. Similarly, multiple databases were searched for studies regarding TN treated with fSRS where patient-level data was included from 2004-2020. Pain levels, via the Barrow Neurological Institute (BNI) scale, before and after treatment were analyzed. Pooled analysis was performed to compare treatment outcomes between studies using CyberKnife and LINAC modalities.

RESULTS

Twenty-three patients at our institution were treated with LINAC fSRS (median treatment dose: 85 Gy). Most patients had TN refractory to previous procedural treatments. Eight (35%) patients had an excellent posttreatment response (BNI I-II), while 11 (48%) patients had a good result (BNI IIIa/b). Eight patients had recurrence of pain. A total of 30 articles were included in the systematic review, encompassing 1705 patients. At last follow-up, 63.1% (774/1227) of patients endorsed an excellent response, while 16.1% (197/1227) had a good response, and 22.5% (215/957) of patients had recurrence. Pain response, facial numbness rates, and pain recurrence rates were not significantly different between CyberKnife and LINAC modalities.

CONCLUSIONS

Frameless SRS for TN appears to be an efficacious noninvasive option for patients with substantial comorbidities, who have failed other treatment methods, although it can be limited by higher recurrence rates.

EVAULATION OF BLINK REFLEX BETWEEN PATIENTS WITH IDIOPATHIC TRIGEMINAL NEURALGIA AND HEALTHY VOLUNTEERS

The purpose of the study was to find differences in the parameters of the response to the blink reflex (BR) between patients with idiopathic trigeminal neuralgia (TN) and health volunteers. A prospective cohort study was conducted over 2 years. The TN-subgroup included 15 patients (mean age / SD 62.3 ± 10.7 years). Pain-free and healthy volunteers as a HV-subgroup (mean age / SD: 30.8 ± 8.1 years) were recruited from asymptomatic students of dental medicine. Diagnostic parameters were determined by measuring latency to the onset of the BR components from electric stimulation. The following branches of the trigeminal nerve were affected: maxillary branch only (26.7%), mandibular branch only (20%), combined: ophthalmic branch with maxillary branch (6.7%), and ophthalmic branch with mandibular branch (6.7%) respectively, combined maxillary and mandibular branch (26.7%) and affected all three branches (13.4%). The latencies of the BR, left and right side together, between subgroups were significantly higher for values R1 (homolateral early response), R2 (homolateral late response), R2c latency (contralaterally expressed response) in the TN-subgroup (p < 0.05). On the basis of the presence of R1c and R3 latencies and upon considering the abnormal findings of the BR, no statistically significant differences were found between the examined subgroups (p > 0.05). Blink-reflex parameters (R1, R2 and R2c) were significantly abnormal comparing TN-patients with healthy volunteers. The R3 component of the BR was related to noxious stimuli, likewise by innocuous stimuli.

Expression and Biological Functions of miRNAs in Chronic Pain: A Review on Human Studies

Chronic pain is a major public health problem and an economic burden worldwide. However, its underlying pathological mechanisms remain unclear. MicroRNAs (miRNAs) are a class of small noncoding RNAs that post-transcriptionally regulate gene expression and serve key roles in physiological and pathological processes. This review aims to synthesize the human studies examining miRNA expression in the pathogenesis of chronic primary pain and chronic secondary pain. Additionally, to understand the potential pathophysiological impact of miRNAs in these conditions, an in silico analysis was performed to reveal the target genes and pathways involved in primary and secondary pain and their differential regulation in the different types of chronic pain. The findings, methodological issues and challenges of miRNA research in the pathophysiology of chronic pain are discussed. The available evidence suggests the potential role of miRNA in disease pathogenesis and possibly the pain process, eventually enabling this role to be exploited for pain monitoring and management.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Unilateral Approach to Primary Bilateral Trigeminal Neuralgia Via Bilateral Microvascular Decompression

Primary bilateral trigeminal neuralgia is a rare disease characterized by paroxysmal bilateral facial pain confined to the somatosensory distribution of the trigeminal nerve. Nonetheless, while treatment of bilateral trigeminal neuralgia with microvascular decompression (MVD) has been reported, there have been no trials of a unilateral approach for bilateral MVD.

Percutaneous balloon compression technique using intraoperative contrasted DynaCT for the treatment of refractory trigeminal neuralgia: initial experience

OBJECTIVE

Percutaneous balloon compression (BC) is a well-established technique that can provide immediate relief to patients suffering from trigeminal neuralgia (TN). The general procedure of BC uses fluoroscopy imaging to guide the needle through the foramen ovale (FO). The aim of this study was to describe our experience with a novel technique using intraoperative contrast-enhanced DynaCT as an adjunct for more accurate and safer guidance of the needle to the FO.

METHODS

In this study, DynaCT was used to perform BC in 20 TN cases. The three-dimensional path of the needle was pre-planned using DynaCT obtained during the administration of IV contrast. The FO was accessed in a single pass along the path pre-determined from the DynaCT images, avoiding any major arteries and veins. DynaCT was also used for confirmation of the final position of the needle prior to insertion of the balloon as well as for confirmation of the position of the balloon after inflation.

RESULTS

Intravenous contrast-enhanced DynaCT-guided percutaneous BC allowed precise advancement and positioning of the needle within the FO. It facilitated cannulation of the FO along a pre-determined path that avoided any major vascular structures. Clinical outcomes were excellent-all patients had a quick postoperative recovery, and there were no complications.

CONCLUSIONS

The advantages of the contrast-enhanced DynaCT-guided technique include a single precise needle pass and avoidance of vessel injury. Precise placement of the balloon into different aspects of the FO can target trigeminal branches more selectively and allow for a better outcome.

Trigeminal Neuralgia Caused by Dural Arteriovenous Fistula of the Transverse-Sigmoid Sinus without Vessel Compression at Root Entry Zone

Objective

The vessel compression at the root entry zone (REZ) of trigeminal nerve is a common cause of trigeminal neuralgia (TN). We report a rare case of TN caused by dural arteriovenous fistula (DAVF) of the transverse-sigmoid sinus without vessel compression at REZ.

Case Presentation

A 45-year-old woman presented with right side tinnitus and was diagnosed as a DAVF of the right transverse-sigmoid sinus (Borden Type I). After that, the facial pain in the right maxillary nerve area appeared and was getting worse. DSA revealed an enlargement of the artery of foramen rotundum (AFR) as one of the feeding arteries. MRI revealed no evidence of vascular compression at REZ. The patient was treated with transarterial embolization (TAE) with Onyx via the branches of the middle meningeal artery (MMA) and occipital artery (OA). The AFR decreased in size and the facial pain was improved. However, the DAVF and the facial pain were recurred. Finally, the DAVF was completely embolized with transvenous embolization (TVE). During 1-year follow-up period, the patient remained free of pain without recurrence.

Conclusion

The compression of the maxillary nerve by the AFR might result in TN, because the pain diminished after shrinkage of the AFR by the endovascular treatment.

Vascular entrapment neuropathy of the tibial nerve within the gastrocnemius muscle

Background:

Vascular compression is an extremely rare cause of mononeuropathy and compression of selective tibial nerve branches is an additionally a rare finding and makes diagnosis difficult.

Case Description:

Here within, we describe the case of a 41-year-old male who presented with isolated mononeuropathy of the medial gastrocnemius (MG) branch of the tibial nerve presented as persistent fasciculations and atrophy. After electromyography and clinical evaluation, surgical exploration was recommended. A vascular bundle was found to be compressing the MG branch of the tibial nerve and thus was ligated to decompress the nerve. Postoperatively, all fasciculations improved and muscle atrophied improved.

Conclusion:

Vascular compression resulting in mononeuropathy of the peripheral nerves is a rare clinical entity. Clinicians should include these etiologies on their differential when considering surgical exploration of mononeuropathies.

Microvascular Decompression for Trigeminal Neuralgia: Experience of a Tertiary Care Center in India and a Brief Review of Literature

Background

Trigeminal neuralgia (TN) is a devastating condition causing significant patient discomfort and morbidity hampering quality of life. Of the many treatment options available, microvascular decompression (MVD) of the trigeminal nerve is widely performed. However, the procedure is not risk-free.

Objective

The study aimed to describe our experience of treating TN via MVD and long-term follow-up of the patients treated by this modality.

Materials and Methods

It is a 5-year retrospective analysis of the database of patients with idiopathic TN treated with MVD at our institute. A total of 106 patients fulfilling the criteria of idiopathic TN by International Classification of Headache Disorders, 3^rd ed.ition and available for follow-up for at least 1-year post-procedure were included in the study.

Results

Of the 106 patients, 58 (54.7%) were female and 48 (45.3%) were male with a mean age of 55 years (range 22-75 years). Vascular compression of the trigeminal nerve was seen in all cases; arterial compression in 82%, both artery and vein 14.5% while unidentified vessels were the culprit in 3.8% of the patients. There were no intra- or post-operative deaths. The best response was achieved at 1 month following the procedure where 85% of the patients achieved excellent outcomes.

Conclusion

In experienced hands, MVD is still a safe and cost-effective modality over a myriad of treatment options available for TN in patients of all ages. The absence of adhesions, indentations, and distortion of the trigeminal nerve are positive predictors of excellent outcomes in the long run.

Subacute vision loss after microvascular decompression for trigeminal neuralgia

Microvascular decompression is the surgery of choice for typical trigeminal neuralgia (TN) that fails conservative medical management. Visual loss after MVD is a rare complication that has not been reported. In this article, we present a patient who developed delayed visual loss and papilledema from transverse sinus stenosis resulting from bone wax compression after MVD for TN. While waxing the edges of a retrosigmoid craniotomy may seem mundane, meticulous care should be taken to ensure that there is no compression of the venous sinuses, as this could lead to intracranial hypertension.

The effect of IL-6/Piezo2 on the trigeminal neuropathic pain

The nature of trigeminal neuropathic pain (TN) attacks is regarded as the ignition of ectopic action potentials from the trigeminal root following vascular compression, which seemed to be related to transmembrane proteins and inflammation factors. This study focused on the mechanosensitive channel Piezo2 and cytokine IL-6. The chronic constriction injury of infraorbital nerve in SD rats was used to establish the TN model. The trigeminal ganglion was then achieved to perform immunocytochemistry studies. A significant upregulation of Piezo2 and IL-6 was showed in the TN model rats. The Piezo2 positive accounted for 72.3±9.5% in those IL-6 positive neurons. The Piezo2 co-localized with CGRP, IB4 and NF-200 but not with GFAP, which implied that it was expressed in both the C-type and the A-type neurons. After administration of GsMTx4 or anti-rat IL-6 antibody in the TN model, the dynamic allodynia and pinprick hyperalgesia scores as well as the mechanical threshold changed significantly. In the sham-operation rates, with local administration of IL-6, an upregulation of Piezo2 was also exhibited. Our study demonstrated that the up-regulation of Piezo2 in the pain afferent neurons following trigeminal nerve injury may play a role in the development of the neuralgia. Meanwhile, the expression of Piezo2 may be modulated by inflammatory cytokines, such as IL-6.

Efficacy of Internal Neurolysis for Trigeminal Neuralgia without Vascular Compression

BACKGROUND AND OBJECTIVE

 Trigeminal neuralgia is a common neurologic disease that seriously impacts a patient's quality of life. We retrospectively investigated the efficacy and safety of internal neurolysis (nerve combing) for trigeminal neuralgia without vascular compression.

PATIENTS AND METHODS

 This study was a retrospective review of all patients with trigeminal neuralgia who were admitted between January 2014 and February 2019. A subgroup of 36 patients had no vascular compression at surgery and underwent internal neurolysis. Chart review and postoperative follow-up were performed to assess the overall outcomes of internal neurolysis.

RESULTS

 Thirty-six patients were identified, with a mean age of 44.89 ± 7.90 (rang: 31-65) years and a disease duration of 5.19 ± 2.61 years. The immediate postoperative pain relief (Barrow Neurological Institute [BNI] pain score of I or II) rate was 100%. The medium- to long-term pain relief rate was 91.7%. Three patients experienced recurrence. Facial numbness was the primary postoperative complication. Four patients with a score of III on the BNI numbness scale immediately after surgery had marked improvement at 6 months. No serious complications occurred.

CONCLUSION

 Internal neurolysis is a safe and effective treatment for trigeminal neuralgia without vascular compression or clear responsible vessels.

Glial and neuroimmune cell choreography in sexually dimorphic pain signaling

Chronic pain is a major global health issue that affects all populations regardless of sex, age, ethnicity/race, or country of origin, leading to persistent physical and emotional distress and to the loss of patients' autonomy and quality of life. Despite tremendous efforts in the elucidation of the mechanisms contributing to the pathogenesis of chronic pain, the identification of new potential pain targets, and the development of novel analgesics, the pharmacological treatment options available for pain management remain limited, and most novel pain medications have failed to achieve advanced clinical development, leaving many patients with unbearable and undermanaged pain. Sex-specific susceptibility to chronic pain conditions as well as sex differences in pain sensitivity, pain tolerance and analgesic efficacy are increasingly recognized in the literature and have thus prompted scientists to seek mechanistic explanations. Hence, recent findings have highlighted that the signaling mechanisms underlying pain hypersensitivity are sexually dimorphic, which sheds light on the importance of conducting preclinical and clinical pain research on both sexes and of developing sex-specific pain medications. This review thus focuses on the clinical and preclinical evidence supporting the existence of sex differences in pain neurobiology. Attention is drawn to the sexually dimorphic role of glial and immune cells, which are both recognized as key players in neuroglial maladaptive plasticity at the origin of the transition from acute pain to chronic pathological pain. Growing evidence notably attributes to microglial cells a pivotal role in the sexually dimorphic pain phenotype and in the sexually dimorphic analgesic efficacy of opioids. This review also summarizes the recent advances in understanding the pathobiology underpinning the development of pain hypersensitivity in both males and females in different types of pain conditions, with particular emphasis on the mechanistic signaling pathways driving sexually dimorphic pain responses.

Invasive and Non-Invasive Electrical Neuromodulation in Trigeminal Nerve Neuralgia: A Systematic Review and Meta-Analysis

BACKGROUND

Trigeminal neuralgia is a chronic disease characterized by intense facial pain that is caused by trigeminal nerve affectation. It usually affects adults from 50 years of age, and is more frequent in women. Additionally, it presents serious psychological effects that often lead to depression, which is why it is considered highly disabling. The therapeutic approach is based on the modification of nerve activity through electrical, surgical or chemical stimulation in specific regions of the nervous system.

OBJECTIVE

To perform a meta-analysis of the scientific literature related to invasive and non-invasive electrical neuromodulation of trigeminal neuralgia, in order to assess their effects over pain and adverse effects.

METHODS

A literature search was conducted in 4 databases, followed by a manual search of articles on invasive or non-invasive electrical neuromodulation to control the pain of trigeminal neuralgia, including the last 15 years.

RESULTS

Regarding non-invasive methods, clinical trials did not present enough results in order to perform a meta-analysis. Regarding invasive methods, clinical trials meta-analysis showed no statistical differences between different treatment methods. In all cases, improvements in patients' pain were reported, although results regarding adverse effects were variable.

CONCLUSION

In the treatment of trigeminal neuralgia, the continuous radiofrequency provides better short and medium-term results, but pulsed radiofrequency shows less adverse effects after treatment, and has better results in the long-term.

Evaluation of circulating microRNA expression in patients with trigeminal neuralgia: An observational study

Trigeminal neuralgia (TN) is a chronic neuropathic pain that seriously affects the daily life of patients. There is increasing evidence that microRNAs (miRNAs) play an important role in the development of neuropathic pain.In this study, the TaqMan Low Density Array (TLDA) was used to analyze the serum miRNA levels of 28 TN patients, and 31 healthy people without any neuropathic pain were used as controls.The results showed that the expression profile of serum miRNA in TN patients was different from that in healthy controls. Compared with the control group, 13 miRNAs in the serum of TN patients were up-regulated and 115 miRNAs were down-regulated by >2 times. Quantitative reverse transcription PCR (RT-qPCR) analysis and receiver operating characteristic (ROC) curve were performed. The analysis further confirmed that the expression levels of 4 miRNAs, including miR-132-3p, miR-146b-5p, miR-155-5p, and miR-384, were significantly higher than those of healthy controls, and the difference was statistically significant.This study preliminarily confirmed the changes of serum miRNA expression profile in TN patients. Among them, 4 kinds of serum miRNA are likely to be related to the occurrence and development of TN.

Clinical Outcome of Percutaneous Trigeminal Nerve Block in Elderly Patients in Outpatient Clinics

Objective

Trigeminal neuralgia (TN) is a severe neuropathic condition that affects several elderly patients. It is characterized by uncontrolled pain that significantly impacts the quality of life of patients. Therefore, the condition should be treated as an emergency. In the majority of patients, pain can be controlled with medication; however, other treatment modalities are being explored in those who become refractory to drug treatment. The use of the trigeminal nerve block with a local anesthetic serves as an excellent adjunct to drug treatment. This technique rapidly relieves the patient of pain while medications are being titrated to effective levels. We report the efficacy and safety of percutaneous trigeminal nerve block in elderly patients with TN at our outpatient clinic.

Methods

Twenty-one patients older than 65 years with TN received percutaneous nerve block at our outpatient clinic. We used bupivacaine (1 mL/injection site) to block the supraorbital, infraorbital, superior alveolar, mental, and inferior alveolar nerves according to pain sites of patients.

Results

All patients reported relief from pain, which decreased by approximately 78% after 2 weeks of nerve block. The effect lasted for more than 4 weeks in 12 patients and for 6 weeks in two patients. There were no complications.

Conclusion

Percutaneous nerve block procedure performed at our outpatient clinic provided immediate relief from pain to elderly patients with TN. The procedure is simple, has no serious side effects, and is easy to apply.

Creation of a novel trigeminal tractography atlas for automated trigeminal nerve identification

Diffusion MRI (dMRI) tractography has been successfully used to study the trigeminal nerves (TGNs) in many clinical and research applications. Currently, identification of the TGN in tractography data requires expert nerve selection using manually drawn regions of interest (ROIs), which is prone to inter-observer variability, time-consuming and carries high clinical and labor costs. To overcome these issues, we propose to create a novel anatomically curated TGN tractography atlas that enables automated identification of the TGN from dMRI tractography. In this paper, we first illustrate the creation of a trigeminal tractography atlas. Leveraging a well-established computational pipeline and expert neuroanatomical knowledge, we generate a data-driven TGN fiber clustering atlas using tractography data from 50 subjects from the Human Connectome Project. Then, we demonstrate the application of the proposed atlas for automated TGN identification in new subjects, without relying on expert ROI placement. Quantitative and visual experiments are performed with comparison to expert TGN identification using dMRI data from two different acquisition sites. We show highly comparable results between the automatically and manually identified TGNs in terms of spatial overlap and visualization, while our proposed method has several advantages. First, our method performs automated TGN identification, and thus it provides an efficient tool to reduce expert labor costs and inter-operator bias relative to expert manual selection. Second, our method is robust to potential imaging artifacts and/or noise that can prevent successful manual ROI placement for TGN selection and hence yields a higher successful TGN identification rate.

Trigeminal Neuralgia Induced Headache: A Case Report and Literature Review

A 51-year-old woman with a past medical history of migraine presented with severe headache for the last three weeks. The pain was intermittent and throbbing in nature. She has not experienced any headaches in the past several years. She took her migraine pills and over-the-counter analgesics, but the pain did not resolve. Initial evaluation including physical exam and neurological exam was normal. Her serum chemistry was unremarkable and CT scan of the brain was nonsignificant. The patient was diagnosed with possible trigeminal neuralgia and the pain resolved after being started on tegral (carbamazepine). Unilateral headache is a typical presentation of atypical trigeminal neuralgia and is rarely reported in literature.

Increased CSF Levels of Apolipoproteins and Complement Factors in Trigeminal Neuralgia Patients-In Depth Proteomic Analysis Using Mass Spectrometry

The main cause of trigeminal neuralgia (TN) is compression of a blood vessel at the root entry zone of the trigeminal nerve. However, a neurovascular conflict does not seem to be the only etiology and other mechanisms are implicated in the development of the disease. We hypothesized that TN patients may have distinct protein expression in the CSF. In this study, lumbar CSF from TN patients (n = 17), scheduled to undergo microvascular decompression, and from controls (n = 20) was analyzed and compared with in depth mass spectrometry TMTbased quantitative proteomics. We identified 2552 unique proteins, of which 46 were significantly altered (26 increased, and 20 decreased, q-value < .05) in TN patients compared with controls. An over-representation analysis showed proteins involved in high-density lipoprotein, such as Apolipoprotein A4, Apolipoprotein M, and Apolipoprotein A1, and the extracellular region, including proteins involved in the complement cascade to be over-represented. We conclude that TN patients have distinct protein expression in the CSF compared to controls. The pathophysiological background of the protein alterations found in this study warrants further investigation in future studies. PERSPECTIVE: In this article, cerebrospinal fluid from patients with trigeminal neuralgia was analyzed using in depth shotgun proteomics, revealing 46 differentially expressed proteins compared to controls. Among these, apolipoproteins and proteins involved in the complement system were elevated and significantly over-represented, implying an inflammatory component in the pathophysiology of the disease.

Efficacy and Safety of Percutaneous Ozone Injection Around Gasserian Ganglion for the Treatment of Trigeminal Neuralgia: A Multicenter Retrospective Study

Background

Ozone injection around Gasserian ganglion (OIAGG) has been reported to be an effective treatment for trigeminal neuralgia (TN); however, there remain areas for improvement. To overcome one of these limitations, a multicenter examination of application would be extremely helpful.

Objective

The goal of this report was to assess the efficacy of OIAGG for refractory TN across multiple centers and to explore factors predictive of successful treatment.

Design

A multicenter, retrospective study.

Setting

The study was conducted across 3 pain centers across China.

Patients and Methods

A total of 103 subjects from 3 pain centers were enrolled in the study. An ozone-oxygen mixture gas at a concentration of 30 µg/mL was injected into the area around the Gasserian ganglion performed under C-arm X-ray guidance. Primary outcome measures included a pain assessment using a visual analog scale (VAS) and the Barrow Neurological Institute (BNI) pain intensity scale. Clinical assessment of patients for these outcome measures was performed at pretreatment, post-treatment, 6 months, 1 year and 2 years after the OIAGG.

Results

Successful pain relief was defined as a score within BNI grades I–IIIa. The pain relief rates at post-treatment, 6 months, 1 year and 2 years after the procedure were 88.35%, 86.87%, 84.46% and 83.30%, respectively. The VAS at each observation time point was significantly different from the preoperative levels (P<0.05). Logistic regression analysis showed that previous nerve damage had a significant effect on the treatment results. No significant complications or side effects were found during or after treatment.

Conclusion

This multicenter research confirms our previous single center results that OIAGG is both effective and safe for patients with TN.

Percutaneous imaging-guided techniques for the treatment of benign neuropathic pain

To date, conservative management including physical and/or systemic pharmacologic therapy is considered as the first line approach for the management of neuropathic pain syndromes. In the era of an opioid overdose crisis with an increased concern upon the risks and harms arising from the misuse of medicines for pain management, percutaneous minimally invasive techniques such as nerve infiltrations as well as neurolysis or neuromodulation techniques can be proposed to control pain and improve life quality. Computed tomography can serve as an ideal guiding technique due to its specific characteristics including precise anatomic delineation, high spatial resolution and good tissue contrast. The purpose of this review is to make the reader familiar with the most common indications for minimally invasive imaging-guided techniques in patients with neuralgia and provide current evidence regarding technical considerations.

IL-6 contributes to Nav1.3 up-regulation in trigeminal nerve following chronic constriction injury

Background: To verify the hypothesis that the nature of trigeminal neuralgia (TN) is an ectopic impulse induced by sodium channel modulated by cytokines, we conducted an animal study using the infraorbital nerve chronic constriction injury (CCI) model in rats.Method: The expression of Nav1.3 or IL-6 in the infraorbital nerve (ION) and trigeminal ganglion (TG) were detected by western blot and immunocytochemistry after administration of antisense oligodeoxynucleotide sequence (AS), IL-6 or Anti-IL-6.Results: With intrathecal administration of AS or mismatch oligodeoxynucleotide sequence (MM) in the CCI rats, the Nav1.3-IR in ION and TG accounted for 2.2 ± 0.51% and 8.5 ± 3.1% in AS+CCI group vs. 6.9 ± 1.3% and 38.7 ± 4.8% in MM+CCI group (p < 0.05), respectively. While with local administration of IL-6 in those with sham operation, it accounted for 7.4 ± 2.1% and 45.5 ± 3.4% in IL-6+ sham group vs. 1.9 ± 0.67% and 8.1 ± 1.3% in vehicle+sham group (p < 0.05); with local administration of anti-IL-6 in CCI rats, 4.5 ± 0.78% and 32.1 ± 9.6% in Anti-IL-6+ CCI group vs 8.9 ± 2.1% and 61.4 ± 11.2% in vehicle+CCI group (p < 0.05).Discussion: We believe that the emergence of Na_v1.3 from the compressed trigeminal nerve might be an important structural basis for the development of the ectopic excitability on the axon and IL-6 may play a role of necessary precondition.

Gamma Knife Radiosurgery on the Trigeminal Root Entry Zone for Idiopathic Trigeminal Neuralgia: Results and a Review of the Literature

Trigeminal neuralgia (TN) is a chronic disorder of the trigeminal nerve characterized by repeated electrical shock-like sensations on one side of the face. It can cause severe pain in the face and disrupt or impair quality of life in patients. Options for the management of TN consist of pharmacological and surgical treatments, including Gamma Knife radiosurgery (GKRS). GKRS has been used for TN for a long time because of its low rate of complications and high success rate. Moreover, GKRS can be of use for drug-resistant TN patients who are poor surgical candidates due to medical comorbidities, patients of older age, or patients who refuse invasive therapy. We reviewed the rationale, effects, safety, and current treatment policies of GKRS for TN in view of our institution's results and a review of the literature to date.

Anatomical assessment of trigeminal nerve tractography using diffusion MRI: A comparison of acquisition b-values and single- and multi-fiber tracking strategies

•

Investigation of the performance of multiple dMRI acquisitions and fiber models for trigeminal nerve (TGN) identification.

•

Expert rating study of over 1000 TGN visualizations using seven proposed expert rating anatomical criteria.

•

The two-tensor tractography method had better performance on identifying true positive structures, while generating more false positive streamlines in comparison to the single-tensor tractography method.

•

TGN tracking performance was significantly different across the three b-values for almost all structures studied.

Background

The trigeminal nerve (TGN) is the largest cranial nerve and can be involved in multiple inflammatory, compressive, ischemic or other pathologies. Currently, imaging-based approaches to identify the TGN mostly rely on T2-weighted magnetic resonance imaging (MRI), which provides localization of the cisternal portion of the TGN where the contrast between nerve and cerebrospinal fluid (CSF) is high enough to allow differentiation. The course of the TGN within the brainstem as well as anterior to the cisternal portion, however, is more difficult to display on traditional imaging sequences. An advanced imaging technique, diffusion MRI (dMRI), enables tracking of the trajectory of TGN fibers and has the potential to visualize anatomical regions of the TGN not seen on T2-weighted imaging. This may allow a more comprehensive assessment of the nerve in the context of pathology. To date, most work in TGN tracking has used clinical dMRI acquisitions with a b-value of 1000 s/mm² and conventional diffusion tensor MRI (DTI) tractography methods. Though higher b-value acquisitions and multi-tensor tractography methods are known to be beneficial for tracking brain white matter fiber tracts, there have been no studies conducted to evaluate the performance of these advanced approaches on nerve tracking of the TGN, in particular on tracking different anatomical regions of the TGN.

Objective

We compare TGN tracking performance using dMRI data with different b-values, in combination with both single- and multi-tensor tractography methods. Our goal is to assess the advantages and limitations of these different strategies for identifying the anatomical regions of the TGN.

Methods

We proposed seven anatomical rating criteria including true and false positive structures, and we performed an expert rating study of over 1000 TGN visualizations, as follows. We tracked the TGN using high-quality dMRI data from 100 healthy adult subjects from the Human Connectome Project (HCP). TGN tracking performance was compared across dMRI acquisitions with b = 1000 s/mm², b = 2000 s/mm² and b = 3000 s/mm², using single-tensor (1T) and two-tensor (2T) unscented Kalman filter (UKF) tractography. This resulted in a total of six tracking strategies. The TGN was identified using an anatomical region-of-interest (ROI) selection approach. First, in a subset of the dataset we identified ROIs that provided good TGN tracking performance across all tracking strategies. Using these ROIs, the TGN was then tracked in all subjects using the six tracking strategies. An expert rater (GX) visually assessed and scored each TGN based on seven anatomical judgment criteria. These criteria included the presence of multiple expected anatomical segments of the TGN (true positive structures), specifically branch-like structures, cisternal portion, mesencephalic trigeminal tract, and spinal cord tract of the TGN. False positive criteria included the presence of any fibers entering the temporal lobe, the inferior cerebellar peduncle, or the middle cerebellar peduncle. Expert rating scores were analyzed to compare TGN tracking performance across the six tracking strategies. Intra- and inter-rater validation was performed to assess the reliability of the expert TGN rating result.

Results

The TGN was selected using two anatomical ROIs (Meckel's Cave and cisternal portion of the TGN). The two-tensor tractography method had significantly better performance on identifying true positive structures, while generating more false positive streamlines in comparison to the single-tensor tractography method. TGN tracking performance was significantly different across the three b-values for almost all structures studied. Tracking performance was reported in terms of the percentage of subjects achieving each anatomical rating criterion. Tracking of the cisternal portion and branching structure of the TGN was generally successful, with the highest performance of over 98% using two-tensor tractography and b = 1000 or b = 2000. However, tracking the smaller mesencephalic and spinal cord tracts of the TGN was quite challenging (highest performance of 37.5% and 57.07%, using two-tensor tractography with b = 1000 and b = 2000, respectively). False positive connections to the temporal lobe (over 38% of subjects for all strategies) and cerebellar peduncles (100% of subjects for all strategies) were prevalent. High joint probability of agreement was obtained in the inter-rater (on average 83%) and intra-rater validation (on average 90%), showing a highly reliable expert rating result.

Conclusions

Overall, the results of the study suggest that researchers and clinicians may benefit from tailoring their acquisition and tracking methodology to the specific anatomical portion of the TGN that is of the greatest interest. For example, tracking of branching structures and TGN-T2 overlap can be best achieved with a two-tensor model and an acquisition using b = 1000 or b = 2000. In general, b = 1000 and b = 2000 acquisitions provided the best-rated tracking results. Further research is needed to improve both sensitivity and specificity of the depiction of the TGN anatomy using dMRI.

Microvascular Decompression for Trigeminal Neuralgia in Patients with Multiple Sclerosis: Predictors of Treatment Success

BACKGROUND

Microvascular decompression (MVD) is highly effective in managing the neuropathic facial pain of trigeminal neuralgia (TN). Its utility in patients with TN and concurrent multiple sclerosis (MS) has been a subject of debate. The goal of this study was to identify demographic and perioperative variables associated with favorable outcome after MVD over the past 20 years in patients from our institution.

METHODS

A retrospective analysis of our cohort of 33 patients diagnosed with MS and TN who underwent MVD between 1997 and 2017 to treat neuropathic facial pain was performed. Perioperative variables included MS disease burden, findings on preoperative magnetic resonance imaging (MRI), TN pain severity, and the presence of intraoperative neurovascular compression. MS disease burden was quantified using the Expanded Disability Status Scale. Preoperative and postoperative pain severity was quantified using the Barrow Neurological Institute (BNI) pain severity scale.

RESULTS

A total of 33 patients with TN and MS were treated with MVD at our institution (out of the 632 total MVDs performed) between 1997 and 2017. Twenty-two patients (67%) maintained a reduction in pain at a mean follow-up of 53.5 months. Higher preoperative BNI pain intensity score was associated with unfavorable outcome after MVD (P = 0.006). No associations were identified between MS disease burden, presence of neurovascular compression or pontine demyelinating plaques on MRI, or intraoperative findings of neurovascular compression and treatment outcomes.

CONCLUSIONS

MVD is a reasonable treatment option for patients with TN and MS, although the rate of freedom from pain is lower than that for the general TN population. Preoperative pain severity may be a predictor of treatment success.

Neuroanatomical Determinants of Secondary Trigeminal Neuralgia: Application of 7T Ultra-High-Field Multimodal Magnetic Resonance Imaging

BACKGROUND

Seven-Tesla (7T) magnetic resonance imaging (MRI) has demonstrated value for evaluating a variety of intracranial diseases. However, its utility in trigeminal neuralgia has received limited attention. The authors of the present study applied ultra-high field multimodal MRI to two representative patients with secondary trigeminal neuralgia due to epidermoid tumors to illustrate the possible clinical and surgical advantages of 7T compared with standard clinical strength imaging. Techniques included co-registration of multiple 7T sequences to optimize the detection of potential concurrent neurovascular and neoplasm-derived compression.

METHODS

7T MRI studies were performed using a whole body scanner. Two- and three-dimensional renderings of potential neurovascular conflict were created by co-registering time-of-flight angiography and T2-weighted turbo spin echo images in MATLAB and GE software. Detailed comparisons of the various field strength images were provided by a collaborating neuroradiologist (B.D.).

RESULTS

7T MRI clearly illustrated minute tumor-adjacent vasculature. In contrast, conventional, low-field imaging did not consistently provide adequate details to distinguish cerebrospinal fluid pulsatility from vessels. The tumor margins, although distinct from the trigeminal nerve fibers at 7T, blended with those of the surrounding structures at 3T. Two- and three-dimensional co-registration of time-of-flight angiography with T2-weighted MRI suggested that delicate, intervening vasculature may have contributed to these illustrative patients' symptomatology.

CONCLUSIONS

7T provided superior visualization of vital landmarks and subtle nerve and vessel features. Co-registration of various advanced 7T modalities may help to resolve complex disease etiologies. Future studies should explore the extent to which this dual etiology might persist across tumor types and utilize diffusion-based techniques to quantify what microstructural differences might exist between patients with trigeminal neuralgia from varying etiologies.