Trigeminal neuralgia: Comparison of characteristics and impact in patients with or without multiple sclerosis

Different mechanisms guide the antinociceptive effect of bone marrow-mononuclear cells and bone marrow-mesenchymal stem/stromal cells in trigeminal neuralgia

AIMS

Trigeminal neuralgia (TN) is a type of chronic orofacial pain evoked by trivial stimuli that manifests as episodes of excruciating and sudden, recurrent paroxysmal pain. Most patients are refractory to pharmacological therapy used for the treatment of TN. Mononuclear cells (MNC) and mesenchymal stem/stromal cells (MSC) have shown therapeutic potential in painful neuropathies, but their mechanism of action is not fully understood. The present work aimed to investigate the antinociceptive effect and mechanism of action of MNC and MSC in experimental TN.

MATERIALS AND METHODS

Mice submitted to the chronic constriction injury of the infraorbital nerve (CCI-ION) mouse model of TN received a single intravenous injection of saline, MNC, or MSC (1 × 106 cells/mouse). The effect of the treatments on the behavioral signs of painful neuropathy, morphological aspects of the infraorbital nerve, and inflammatory and oxidative stress markers in the infraorbital nerve were assessed.

KEY FINDINGS

MNC and MSC improved behavioral painful neuropathy, activated key cell signaling antioxidant pathways by increasing Nrf2 expression, and reduced the proinflammatory cytokines IL-1β and TNF-α. However, treatment with MSC, but not MNC, was associated with a sustained increase of IL-10 and with the re-establishment of the morphometric pattern of the infraorbital nerve, indicating a difference in the mechanism of action between MNC and MSC. In line with this result, in IL-10 knockout mice, MSC transplantation did not induce an antinociceptive effect.

SIGNIFICANCE

Importantly, these data suggest an IL-10-induced disease-modifying profile related to MSC treatment and reinforce cell therapy's potential in treating trigeminal neuralgia.

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.

The role of multiple sclerosis subtype in microvascular decompression outcomes for patients with trigeminal neuralgia

OBJECTIVES

While patients with concomitant trigeminal neuralgia (TN) and multiple sclerosis (MS) are understood to experience a more intractable pain phenotype, whether TN pain outcomes differ by the presenting MS subtype is not well characterized. This study's objective is to compare post-operative pain and numbness outcomes following microvascular decompression (MVD) in TN patients with either relapsing-remitting MS (RRMS) or progressive MS.

METHODS

We retrospectively reviewed all TN patients who underwent MVDs at our institution from 2007 to 2020. Of the 1044 patients reviewed, 45 (4.3%) patients with MS were identified. Patient demographics, procedural characteristics, and post-operative pain and numbness scores were recorded and compared. Factors associated with pain recurrence were assessed using survival analyses and multivariate regressions.

RESULTS

Of the resulting 45 MS patients, 34 (75.6%) patients presented with the RRMS subtype, whereas 11 (24.4%) patients exhibited progressive MS. Using an adjusted multivariate ordinal regression, the subtype of MS was not significantly associated with the Barrow Neurological Institute (BNI) pain score at final follow-up. Using a Kaplan-Meier survival analysis and a multivariate Cox proportional hazards regression, respectively, RRMS was significantly associated with a shorter post-operative pain-free interval (p = 0.04) as well as a greater risk for pain recurrence (p = 0.02).

CONCLUSIONS

Although the degree of pain at final follow-up may not differ, RRMS patients are at increased risk for pain recurrence following MVD for TN. These results align with a growing understanding that neuroinflammation may play a significant role in TN pain.

Prevalence of temporomandibular disorders in people with multiple sclerosis: A systematic review and meta-analysis

OBJECTIVE

To explore the prevalence of temporomandibular disorders (TMD) in patients affected by multiple sclerosis (MS) and whether there is a correlation between TMD prevalence and MS severity.

METHODS

PubMed, Web of Science, and Lilacs were systematically searched until July 30 2022, to identify studies presenting patients affected by MS and whether there is a correlation between TMD prevalence and MS severity.

RESULTS

Out of 292 papers, 8 studies were included with 1312 study participants. Among the 8 studies, 5 had a control group; 5 used the RDC/TMD criteria, 1 used the NOT-S instrument, and 2 did not define a standardized method to define TMD symptoms. Meta-analysis revealed that the MS group had a higher rate than the control group, showing an association between MS and TMD (RR 2.10; 95% CI: 1.21-3.65).

CONCLUSION

These findings show an association between TMD and MS.

ABBREVIATIONS

Australian Longitudinal Study of MS (AMSLS); Computed Tomography (CT); Community Periodontal Index of Treatment Needs (CPITN); Central Nervous System (CNS); Decayed, Missing, and Filled (DMF); Decayed, Missing, or Filled Teeth Index (DMFT); Expanded Disability Status Scale (EDSS); European Academy of Craniomandibular Disorders (EACD); Healthy Controls (HC); International Prospective Register of Systematic Reviews (PROSPERO); Multiple Sclerosis (MS); Nordic Orofacial Test-Screening (NOT-S); Participants, model of Intervention, Comparison and Outcome (PICO); Preferred Reporting Items for Systematic Reviews (PRISMA); Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD); Temporomandibular Joint (TMJ); Temporomandibular Disorders (TMD); World Health Organization (WHO).

Pregestational neurological disorders among women of childbearing age—Nationwide data from a 13-year period in Hungary

Objectives

Comprehensive statistics evaluating pregnancies complicated by various medical conditions are desirable for the optimization of prenatal care and for improving maternal and fetal outcomes. The main objective of our study was to assess pregnancies during a 13-year study period with accompanying pregestational neurological disorders in medical history on a nationwide level.

Methods

In the framework of the NEUROHUN 2004–2017 project utilizing medical reports submitted for reimbursement purposes to the National Health Insurance Fund, we included women with at least one labor during 2004–2016 who had at least one pregestational diagnosis of a neurological disorder received within this time frame prior to their first pregnancy during the studied period. Three-digit codes from the 10^th International Classification of Diseases (ICD) were used for the identification and classification of neurological and obstetrical conditions.

Results

Specific inclusion and exclusion criteria were employed during the study process. A total of 744 226 women have been identified with at least one delivery during the study period with 98 792 of them (13.3%) having at least one neurological diagnosis received during 2004–2016 before their first gestation in the time frame of the study. The vast majority of diagnosis codes were related to different types of headaches affecting 69 149 (9.3%) individuals. The most prevalent diagnoses following headaches were dizziness and giddiness (15 589 patients [2.1%]; nerve, nerve root and plexus disorders (10 375 patients [1.4%]); epileptic disorders (7028 patients [0.9%]); neurological diseases of vascular origin (6091 patients [0.8%]); other disorders of the nervous system (5358 patients [0.7%]); and demyelinating diseases of the central nervous system (2129 patients [0.3%]). The present findings of our study show high prevalence of pregestational neurological disorders, the dominance of headaches followed by the rather nonspecific diagnosis of dizziness and giddiness, the relevance of nerve, nerve root and plexus disorders and epilepsy, and the importance of cerebrovascular disorders among women of childbearing age.

Conclusion

The present research findings can help healthcare professionals, researchers and decision makers in adopting specific health policy measures based on nationwide data and further aid the development of new diagnostic and therapeutic algorithms of various neurological manifestations concerning women of childbearing age.

Autologous conditioned serum (Orthokine) injection for treatment of classical trigeminal neuralgia: results of a single-center case series

BACKGROUND

Despite some advances, treatment of trigeminal neuralgia remains a significant challenge. This study determines the efficacy and safety of autologous conditioned serum (Orthokine) injection into the foramen oval to treat refractory trigeminal neuralgia.

CASE PRESENTATION

This is a consecutive case series from the Pain and Palliative Care Department of Imam Reza University Hospital, Tabriz, Iran. Eleven Iranian patients, eligible according to the inclusion and exclusion criteria, aged 45.64 ± 11.58 years (Four male and seven female, all Iranian) with established classical trigeminal neuralgia were injected with Orthokine (2 mL per injection) once a week for three consecutive weeks (total of four injections). Numeric rating scale scores for facial pain intensity and also carbamazepine daily dose were confirmed at pretreatment (T0) and at week 1 (T1), week 2 (T2), week 3 (T3), week 4 (T4), and month 2 (T5) posttreatment. Pain intensity was significantly reduced in the first 3 weeks of follow-up in comparison with baseline (T0 to T3) (8.18 ± 1.99 to 2.82 ± 2.13, p < 0.001), an effect that was retained at week 4 (T4) and month 2 (T5) follow-ups (2.82 ± 2.13 to 3.36 ± 2.69, p = 0.886). Carbamazepine consumption was significantly reduced in the first 3 weeks of follow-up in comparison with baseline (T0 to T3) (636.36 ± 307.48 to 200.00 ± 296.64, p = 0.003), an effect that was retained at week 4 and month 2 follow-ups (200.00 ± 296.64 to 200.00 ± 282.84, p = 0.802). There were no serious adverse events in participants.

CONCLUSION

Orthokine injection led to consistent pain relief and reduced carbamazepine dosage in patients with trigeminal neuralgia, with acceptable safety.

The Long-Term Outcome of Radiofrequency Ablation in Multiple Sclerosis-Related Symptomatic Trigeminal Neuralgia

BACKGROUND

Radiofrequency lesioning (RFL) is used to surgically manage trigeminal neuralgia (TN) secondary to multiple sclerosis (MS). However, the long-term outcome of RFL has not been established.

OBJECTIVE

To investigate the long-term clinical outcome of RFL in MS-related TN (symptomatic trigeminal neuralgia [STN]).

METHODS

During a 23-yr period, institutional data were available for 51 patients with STN who underwent at least one RFL procedure to treat facial pain. Patient outcome was evaluated at a mean follow-up of 69 mo (95% confidence interval; range 52-86 mo). No pain with no medication (NPNM) was the primary long-term outcome measure.

RESULTS

After an initial RFL procedure, immediate pain relief was achieved in 50 patients (98%), and NPNM as assessed at 1, 3, and 6 yr was 86%, 52%, and 22%, respectively. At the last clinical visit after an initial RFL, 23 patients (45%) with pain recurrence underwent repeat RFL; NPNM at 1, 3, and 6 yr after a repeat RFL was 85%, 58%, and 32%, respectively. There was no difference in pain outcome after an initial and repeat RFL ( P = .77). Ten patients with pain recurrence underwent additional RFL procedures. Two patients developed mastication muscle weakness, one patient experienced a corneal abrasion, which resolved with early ophthalmological interventions, and one patient experienced bothersome numbness.

CONCLUSION

RFL achieves NPNM status in STN and can be repeated with similar efficacy.

When intra-operative exploration is the only option, severe medically refractory trigeminal neuralgia

Introduction: Patients with trigeminal neuralgia (TN) are usually treated on an outpatient basis, and symptoms can be controlled using various medical therapeutic options. We present a case of severe TN with an acute on chronic flare, which was now refractory to a wide variety of medical options, had a prolonged inpatient hospitalization, and ultimately required surgery with excellent results.Case: A 54-year-old Hispanic male was admitted with severe left-sided TN. His symptoms gradually became more pronounced and frequent to a point where he was unable to have a meaningful quality of life. A trial of gabapentin, phenytoin, opioids, and NSAIDs had also been unsuccessful before this hospitalization. He had three ER visits before he was finally hospitalized with intractable pain and unfortunately had begun to have suicidal thoughts. Various therapeutic interventions were tried, including escalating doses of opioids and local nerve blocks, but all non-surgical options failed to provide relief. Neurosurgical route was eventually approached, and patient underwent left retro mastoid suboccipital craniectomy. Intraoperatively, the left superior cerebellar artery was found to adhere to the inferior ventral aspect of the left trigeminal nerve root entry zone. Upon decompression patient's symptoms resolved dramatically. Interestingly this vascular compression was not seen on multiple prior brain imaging.Conclusion: TN can severely affect someone's quality of life. It often leads to severe anxiety and depression. Our case represents the importance of proceeding towards surgical options sooner rather than later. An early multi-disciplinary approach is warranted.

The journeys of patients with trigeminal neuralgia on a background of multiple sclerosis

Aim: Multiple sclerosis (MS) is well recognized as a secondary cause for trigeminal neuralgia (TN). In this case series, we detail the management of all the patients with TN and MS (pwTNMS) presenting to a specialist unit. Materials & methods: A prospective patient database was used to extract key clinical data on pharmacological, psychometric and surgical management of 20 pwTNMS. Results: 65% of pwTNMS underwent surgical interventions for management of their pain.12/20 achieved remission periods, through surgery and/or medication. Significant improvement was noted on the global impression of change illustrated by a p < 0.001. Conclusion: pwTNMS require a multifaceted approach combining polypharmacy, surgical interventions and psychological support. Developing self-management skills is crucial if patients are to live well with pain.

Trigeminal neuralgia: An overview from pathophysiology to pharmacological treatments

The trigeminal nerve (V) is the fifth and largest of all cranial nerves, and it is responsible for detecting sensory stimuli that arise from the craniofacial area. The nerve is divided into three branches: ophthalmic (V1), maxillary (V2), and mandibular (V3); their cell bodies are located in the trigeminal ganglia and they make connections with second-order neurons in the trigeminal brainstem sensory nuclear complex. Ascending projections via the trigeminothalamic tract transmit information to the thalamus and other brain regions responsible for interpreting sensory information. One of the most common forms of craniofacial pain is trigeminal neuralgia. Trigeminal neuralgia is characterized by sudden, brief, and excruciating facial pain attacks in one or more of the V branches, leading to a severe reduction in the quality of life of affected patients. Trigeminal neuralgia etiology can be classified into idiopathic, classic, and secondary. Classic trigeminal neuralgia is associated with neurovascular compression in the trigeminal root entry zone, which can lead to demyelination and a dysregulation of voltage-gated sodium channel expression in the membrane. These alterations may be responsible for pain attacks in trigeminal neuralgia patients. The antiepileptic drugs carbamazepine and oxcarbazepine are the first-line pharmacological treatment for trigeminal neuralgia. Their mechanism of action is a modulation of voltage-gated sodium channels, leading to a decrease in neuronal activity. Although carbamazepine and oxcarbazepine are the first-line treatment, other drugs may be useful for pain control in trigeminal neuralgia. Among them, the anticonvulsants gabapentin, pregabalin, lamotrigine and phenytoin, baclofen, and botulinum toxin type A can be coadministered with carbamazepine or oxcarbazepine for a synergistic approach. New pharmacological alternatives are being explored such as the active metabolite of oxcarbazepine, eslicarbazepine, and the new Nav1.7 blocker vixotrigine. The pharmacological profiles of these drugs are addressed in this review.

Operative findings and outcome of microvascular decompression/adhesiolysis for trigeminal neuralgia in multiple sclerosis without demyelinating brain stem lesions

OBJECTIVE

Trigeminal neuralgia (TN) in multiple sclerosis (MS) poses several challenges for treatment. Although these patients often have typical attacks, they may not be considered as candidates for microvascular decompression (MVD). Here we report on surgical findings and long term follow-up of MVD/ adhesiolysis in a series of patients with multiple sclerosis but without demyelinating brain stem lesions.

METHODS

Fifteen patients with MS-related TN underwent MVD/ adhesiolysis. Demyelinating brain stem lesions were excluded radiologically. Outcome of the intervention was assessed according to the Barrow Neurological Institute (BNI) pain intensity score at 3, 12, 24 months follow-up and at the last available follow-up (mean 88.2 months, range 38-146).

RESULTS

All 15 patients benefited from MVD/adhesiolysis and were pain free on the first day of surgery. Intraoperative findings included arterial contact in 7/15 (47 %) patients, venous contact in 9/15 (60 %), and prominent arachnoid thickening in 12/15 (80 %). The distribution of the BNI pain intensity scores showed marked improvement at all follow-up evaluations. Five patients underwent repeat MVD/adhesiolysis for pain recurrence at a mean of 43 months after the first surgery. Long term evaluation at the last available follow-up demonstrated favorable outcome in 13/15 patients (BNI I-IIIa) (87 %), while 2/15 patients had limited benefit (BNI IV).

CONCLUSIONS

MS-related TN in patients without demyelinating brain stem lesions may be related either to vascular conflicts or to focal arachnoiditis at the trigeminal nerve entry zone. MVD/ adhesiolysis may be considered as a useful treatment option in this subgroup of patients with regard to long term outcome.

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

Trigeminal neuralgia (TN), the most common form of severe facial pain, may be confused with an ill-defined persistent idiopathic facial pain (PIFP). Facial pain is reviewed and a detailed discussion of TN and PIFP is presented. A possible cause for PIFP is proposed. (1) Methods: Databases were searched for articles related to facial pain, TN, and PIFP. Relevant articles were selected, and all systematic reviews and meta-analyses were included. (2) Discussion: The lifetime prevalence for TN is approximately 0.3% and for PIFP approximately 0.03%. TN is 15-20 times more common in persons with multiple sclerosis. Most cases of TN are caused by neurovascular compression, but a significant number are secondary to inflammation, tumor or trauma. The cause of PIFP remains unknown. Well-established TN treatment protocols include pharmacotherapy, neurotoxin denervation, peripheral nerve ablation, focused radiation, and microvascular decompression, with high rates of relief and varying degrees of adverse outcomes. No such protocols exist for PIFP. (3) Conclusion: PIFP may be confused with TN, but treatment possibilities differ greatly. Head and neck muscle myofascial pain syndrome is suggested as a possible cause of PIFP, a consideration that could open new approaches to treatment.

Pharmacotherapeutic Options for Managing Pain in Multiple Sclerosis

Pain is a major matter for patients with multiple sclerosis; treatment response is frequently inadequate, with a significant impact on quality of life. The estimated prevalence of pain in multiple sclerosis ranges widely (26-86%), and different subtypes of pain, mediated by specific pathophysiological mechanisms, are described. The aim of this narrative review, performed using a systematic search methodology, was to provide current, evidence-based, knowledge about the pharmacological treatment of the different kinds of pain in multiple sclerosis. We searched for relevant papers within PubMed, EMBASE, the Cochrane Database of Systematic Reviews, and the Clinical Trials database (ClinicalTrials.gov), considering publications up to November 2019. Two authors independently selected studies for inclusion, data extraction, and bias assessment. A total of 27 randomized controlled trials were identified, but in only a few cases, patients with different pain qualities were stratified. Following a mechanism-based approach, treatment of paroxysmal pain and painful tonic spasms should be based on sodium-channel blockers, whereas treatment of ongoing extremity pain should be based on gabapentinoids and antidepressants.

Neuropathic Pain: From Mechanisms to Treatment

Neuropathic pain caused by a lesion or disease of the somatosensory nervous system is a common chronic pain condition with major impact on quality of life. Examples include trigeminal neuralgia, painful polyneuropathy, postherpetic neuralgia, and central poststroke pain. Most patients complain of an ongoing or intermittent spontaneous pain of, for example, burning, pricking, squeezing quality, which may be accompanied by evoked pain, particular to light touch and cold. Ectopic activity in, for example, nerve-end neuroma, compressed nerves or nerve roots, dorsal root ganglia, and the thalamus may in different conditions underlie the spontaneous pain. Evoked pain may spread to neighboring areas, and the underlying pathophysiology involves peripheral and central sensitization. Maladaptive structural changes and a number of cell-cell interactions and molecular signaling underlie the sensitization of nociceptive pathways. These include alteration in ion channels, activation of immune cells, glial-derived mediators, and epigenetic regulation. The major classes of therapeutics include drugs acting on α₂δ subunits of calcium channels, sodium channels, and descending modulatory inhibitory pathways.

Facial Pain: A Comprehensive Review and Proposal for a Pragmatic Diagnostic Approach

BACKGROUND

Facial pain, alone or combined with other symptoms, is a frequent complaint. Moreover, it is a symptom situated at, more than any other pain condition, a crosspoint where several disciplines meet, for example, dentists; manual therapists; ophthalmologists; psychologists; and ear-nose-throat, pain, and internal medicine physicians besides neurologists and neurosurgeons. Recently, a new version of the most widely used classification system among neurologists for headache and facial pain, the International Classification of Headache Disorders, has been published.

OBJECTIVE

The aims of this study were to provide an overview of the most prevalent etiologies of facial pain and to provide a generic framework for the neurologist on how to manage patients presenting with facial pain.

METHODS

An overview of the different etiologies of facial pain is provided from the viewpoint of the respective clinical specialties that are confronted with facial pain. Key message: Caregivers should "think outside their own box" and refer to other disciplines when indicated. If not, a correct diagnosis can be delayed and unnecessary treatments might be given. The presented framework is aimed at excluding life- or organ-threatening diseases, providing several clinical clues and indications for technical investigations, and ultimately leading to the correct diagnosis and/or referral to other disciplines.