Update on trigeminal neuralgia

URB937 Prevents the Development of Mechanical Allodynia in Male Rats with Trigeminal Neuralgia

Cannabinoids are proposed for alleviating neuropathic pain, but their use is limited by cannabimimetic side effects. The inhibition of the fatty acid amide hydrolase (FAAH), the degrading enzyme of the endocannabinoid anandamide, has received attention as an alternative to cannabinoids in the treatment of neuropathic pain. Here, we investigated the effect of URB937, a blood-brain barrier impermeant FAAH inhibitor, on experimentally induced mechanical allodynia in an animal model of trigeminal neuralgia. Male Sprague-Dawley rats were subjected to chronic constriction injury of the infraorbital nerve (IoN-CCI); operated animals were treated sub-chronically with URB937 (1 mg/kg, i.p.) or vehicle before or after trigeminal mechanical allodynia establishment. We also assayed mRNA expression levels of the pain neuropeptide calcitonin gene-related peptide (CGRP) and cytokines in the medulla, cervical spinal cord, and trigeminal ganglion ipsilateral to IoN-CCI using rt-PCR. URB937 treatment prevented the development of mechanical allodynia and IoN-CCI-induced changes in mRNA expression levels of CGRP and cytokines in the evaluated areas. When administered after allodynia development, URB937 prevented IoN-CCI-induced changes in CGRP and cytokine gene expression; this was not associated with a significant abrogation of the mechanical allodynia. These findings suggest that URB937 may counteract, but not reverse, the development of allodynia in trigeminal neuralgia. Further research is needed to elucidate the underlying mechanisms.

“I Still Suffer Every Second of Every Day”: A Qualitative Analysis of the Challenges of Living with Chronic Orofacial Pain

Objective

Chronic orofacial pain is prevalent and debilitating. Psychological and social factors place a heavy burden on this population but are often overlooked. Here, we offer the first comprehensive qualitative conceptualization of the challenges of living with chronic orofacial pain through a biopsychosocial perspective to inform multifaceted care for this population.

Design

We employed a qualitative thematic analysis of open text responses using a hybrid inductive-deductive approach and a biopsychosocial framework.

Methods

Two hundred and sixty participants with chronic orofacial pain responded to an open-ended question: “What is the biggest challenge you face in managing your condition?” by typing their responses into a text box as part of an online survey. We mapped responses onto biomedical, psychological, and social themes (deductive) and concurrently identified findings within each theme that emerged directly from the data (inductive).

Results

Subthemes within the biomedical theme included challenges with biomedical pain management, medication side effects, sensory triggers, physical symptoms of stress/tension, and biological functions and related activities of daily living. Subthemes within the psychological theme included anxiety, depression, emotional symptoms of stress, unpredictability/uncertainty of pain, and psychological and cognitive aspects of medication management. Subthemes within the social theme included social relational, experience with providers, socioeconomics and access to care, and roles and responsibilities.

Conclusion

Chronic orofacial pain is associated with multifaceted challenges. Consideration of individuals’ experiences of biomedical, psychological, and social challenges in the assessment, referral, and treatment of chronic orofacial pain holds the potential to promote more comprehensive, patient-centered care for this population.

Chinese expert consensus on minimally invasive interventional treatment of trigeminal neuralgia

BACKGROUND AND PURPOSE

Trigeminal neuralgia is a common condition that is associated with severe pain, which seriously affects the quality of life of patients. When the efficacy of drugs is not satisfactory or adverse drug reactions cannot be tolerated, minimally invasive interventional therapy has become an important treatment because of its simple operation, low risk, high repeatability and low cost. In recent years, minimally invasive interventional treatments, such as radiofrequency thermocoagulation (RF) of the trigeminal nerve and percutaneous microcompression (PMC), have been widely used in the clinic to relieve severe pain in many patients, however, some related problems remain to be addressed. The Pain Association of the Chinese Medical Association organizes and compiles the consensus of Chinese experts to standardize the development of minimally invasive interventional treatment of trigeminal neuralgia to provide a basis for its clinical promotion and application.

MATERIALS AND METHODS

The Pain Association of the Chinese Medical Association organizes the Chinese experts to compile a consensus. With reference to the evidence-based medicine (OCEBM) system and the actual situation of the profession, the Consensus Development Committee adopts the nominal group method to adjust the recommended level.

RESULTS

Precise imaging positioning and guidance are the keys to ensuring the efficacy and safety of the procedures. RF and PMC are the most widely performed and effective treatments among minimally invasive interventional treatments for trigeminal neuralgia.

CONCLUSIONS

The pain degree of trigeminal neuralgia is severe, and a variety of minimally invasive intervention methods can effectively improve symptoms. Radiofrequency and percutaneous microcompression may be the first choice for minimally invasive interventional therapy.

Clinical and physiopathological aspects of the glossopharyngeal neuralgia

Introduction Glossopharyngeal neuralgia is a rare syndrome characterized by paroxysms of unilateral and severe stabbing pain occurring in the nerve’s distribution. Although other neuralgias are well described in the medical literature, glossopharyngeal neuralgia and its physiopathology are not. The vascular compression at the nerve root entry zone is the primary explanation for the disease. The first-line treatment is pharmacological, including carbamazepine, oxcarbazepine, and gabapentin. Surgical treatment is offered to medication-refractory patients, and microvascular decompression surgery has the best outcomes. Objective To investigate the pathophysiological and clinical aspects of the different presentations of glossopharyngeal neuralgia. Method: A systematic review of the literature including case reports and clinical trials, was done. Results A search of the literature yielded 31 papers that regarded glossopharyngeal neuralgia or its variants. Eight of these reports regarded vagoglossopharyngeal neuralgia. Seven regarded the glossopharyngeal neuralgia followed by or caused by another disease. Conclusion Glossopharyngeal neuralgia is a rare disease and requires further studies on its mechanism and clinical assessment; the physician needs to know how to distinguish it from its variants and underlying causes.

Optimizing Radiosurgery for Trigeminal Neuralgia: Impact of Radiation Dose and Anatomic Target on Patient Outcomes

OBJECTIVE

Radiosurgery is an increasingly popular treatment for trigeminal neuralgia (TN); however, several treatment variables require further study. This meta-analysis was conducted to clarify ambiguity in the literature and optimize treatment parameters.

METHODS

A random-effects proportions meta-analysis using subgroup analysis and meta-regression investigated the association of prescription dose and anatomic target on outcomes in patients with typical TN. The PRISMA guidelines were used. Radiation doses used ranged from 70 to 90 Gy and the anatomic targets were either the root entry zone or a more distal nerve location. Outcome measures were pain at last follow-up and the development of bothersome numbness.

RESULTS

Increasing radiation prescription dose was associated with improved outcomes across all analyzed doses (P < 0.001). Patients treated at a distal trigeminal nerve target had better pain control compared with a root entry zone target (P < 0.001). Despite a higher median dose, a distal target was independently associated with improved pain control. There were similar rates of bothersome numbness across radiation doses and both treatment targets.

CONCLUSIONS

Higher radiation dose was associated with superior pain control without increasing bothersome numbness. Independent of dose, the distal target was also associated with improved pain control. Bothersome numbness was not related to dose or target.

Mechanism underlying cranial nerve rhizopathy

The cranial nerve rhizophathy, commonly presented with trigeminal neuralgia (TN) or hemifacial spasm (HFS), is a sort of hyperexcitability disorders with higher incidence in senior Asian. In this paper, a novel hypothesis on the pathogenesis is proposed and with which some clinical phenomena are explained. In those with crowded cerebellopontine angle in anatomy, the cranial nerve root and surrounding vessel are getting closer and closer to each other with aging and finally the neurovascular conflict happens. As the interfacial friction associated with pulse, the nerve incurs demyelination. Since this pathological change develops to a certain degree, some transmembrane proteins emerge from the nerve due to a series of signaling pathway mediated by inflammatory cytokines. Among them, voltage-gated (Na_v1.3) and mechanosensitive (Piezo2) ion channels may play the important role. With pulsatile compressions, the Piezo2 drives the resting potential toward depolarization forming a state of subthreshold membrane potential oscillation. Under this condition, just an appropriate pressure can make the membrane potential easy to reach threshold and activate the sodium channel, eventually generating conductible action potentials from the axon. When these ectopic action potentials propagate to the central nerve system, an illusion of sharp pain is perceived; while to the nerve-muscle junctions, an attack of irregular muscle constriction occurs. This hypothesis can well explain the symptomatic manifestation of paroxysmal attacks aroused by emotions. When we get nervous or excited, our heart rate and blood pressure alter correspondingly, which may give rise to "a just right pressure" - with specific frequency, amplitude and angle - impacting the suffered nerve to reach the threshold of impulse ignition. After a successful microvascular decompression surgery, the trigger is gone (there is no compression anymore) and the symptom is alleviated. While the postoperative recurrence could be attributable to Teflon granuloma development if had been placed improperly - for this nerve root has been susceptible no matter to arteries or to neoplasms. Besides, it may illustrate the clinical phenomenon that secondary TN or HFS cases are seldom caused by schwannoma: with a proliferative sheath, the nerve root is actually insulated. By contrast, not all neurovascular contacts can lead to the onset: it demands an exclusive extent of demyelination firstly.

Update on Trigeminal Neuralgia

PURPOSE OF REVIEW

To review current treatments for trigeminal neuralgia, with an emphasis on determining which patients may benefit from neurosurgical procedures.

RECENT FINDINGS

A detailed history is the most helpful tool for diagnosing trigeminal neuralgia (TN) and predicting response to neurosurgical treatments. Patients with classic trigeminal neuralgia will describe severe, unilateral, intermittent facial pain that is triggered by innocuous sensory stimuli. In most cases, pain is caused by compression of the trigeminal nerve by a blood vessel near the brainstem. Magnetic resonance imaging is necessary to rule out TN secondary to multiple sclerosis or tumor. Modern high-resolution T2 images may demonstrate neurovascular contact, particularly when analyzed by a neurosurgeon with expertise in TN. Initial management involves a trial of medication, usually carbamazepine or oxcarbazepine. Microvascular decompression (MVD) is safe and effective surgery, for patients with classic TN related to neurovascular compression. For patients with TN secondary to multiple sclerosis, and for patients who are otherwise poor candidates for MVD, neurosurgical options include percutaneous trigeminal rhizotomy and radiosurgery. Neurosurgical procedures are less effective in relieving atypical facial pain. In the clinical evaluation of a patient with facial pain, it is important to distinguish classic trigeminal neuralgia from atypical facial pain. A patient with classic trigeminal neuralgia would benefit from neurosurgical consultation. The advent of high-resolution MRI and MRA sequences now allows a neurosurgeon to detect when neurovascular compression is likely, and select the optimal procedure for treatment.

Case report of primary Sjögren Syndrome with simple trigeminal lesion as initial symptom

PURPOSE

It will provide a reference for early detection, early diagnosis and early treatment of atypical primary Sjogren syndrome with neurological impairment as the first symptom.

METHODS

Case report and Literature review.

RESULTS

Here we report a 30-year-old woman diagnosed with trigeminal damage secondary to pSS who presented atypical trigeminal neuralgia of numbness of the right head and face and persistent prickling-like pain not associated with eating, talking or tooth-brushing, and had no "trigger point". The patient further received rheumatoid immune factor tests, ophthalmic examinations, salivary gland emissioncomputed tomography(ECT) and lip biopsy, and found positive antinuclear antibodies (1:320), atypical xerophthalmia, impaired intake and excretion of bilateral salivary glands and degree II of lip biopsy. The patient received methylprednisolone and antiviral therapy, which showed very good outcome.

CONCLUSIONS

Clinically primary Sjögren Syndrome (pSS) combined with trigeminal lesion is common, but cases of pSS with trigeminal involvement as initial symptom have rarely been reported, which is easy to misdiagnose. This case suggested that the signs of simple trigeminal lesion, especially those with atypical manifestations, could be the early manifestation of other systemic diseases. Attention should be paid to identification of the pathogeny of the primary disease to achieve early identification, diagnosis and treatment.

Antagonism of Transient Receptor Potential Ankyrin Type-1 Channels as a Potential Target for the Treatment of Trigeminal Neuropathic Pain: Study in an Animal Model

Transient receptor potential ankyrin type-1 (TRPA1) channels are known to actively participate in different pain conditions, including trigeminal neuropathic pain, whose clinical treatment is still unsatisfactory. The aim of this study was to evaluate the involvement of TRPA1 channels by means of the antagonist ADM_12 in trigeminal neuropathic pain, in order to identify possible therapeutic targets. A single treatment of ADM_12 in rats 4 weeks after the chronic constriction injury of the infraorbital nerve (IoN-CCI) significantly reduced the mechanical allodynia induced in the IoN-CCI rats. Additionally, ADM_12 was able to abolish the increased levels of TRPA1, calcitonin gene-related peptide (CGRP), substance P (SP), and cytokines gene expression in trigeminal ganglia, cervical spinal cord, and medulla induced in the IoN-CCI rats. By contrast, no significant differences between groups were seen as regards CGRP and SP protein expression in the pars caudalis of the spinal nucleus of the trigeminal nerve. ADM_12 also reduced TRP vanilloid type-1 (TRPV1) gene expression in the same areas after IoN-CCI. Our findings show the involvement of both TRPA1 and TRPV1 channels in trigeminal neuropathic pain, and in particular, in trigeminal mechanical allodynia. Furthermore, they provide grounds for the use of ADM_12 in the treatment of trigeminal neuropathic pain.

The psychosocial impact of orofacial pain in trigeminal neuralgia patients: a systematic review

Trigeminal neuralgia (TN) is characterized by sharp, electric shock-like pain, which can be triggered by trivial stimuli. Although medical and surgical treatments are available for TN, some patients experience refractory pain, which has a significant impact on their quality of life. The aim of this systematic review was to determine the psychosocial impact of orofacial pain in patients with diagnosed TN. A search was initiated in three electronic databases (Embase, MEDLINE, PubMed) to identify potential studies for inclusion in the review. All types of study published in English that reported psychosocial measures using validated psychometric questionnaires were included. A total of 585 articles were retrieved from the search. These were screened thoroughly, leading to the selection of 13 articles for data extraction and final analysis. The results show the chronic overwhelming nature of TN, with pain levels varying from mild to severe. Psychometric scores indicated mild to moderate depression, moderate to severe anxiety, and moderate to severe functional limitation of daily life activities in TN patients. Therefore, psychological support within a multidisciplinary team is recommended for TN patients to help them cope better with their chronic disorder and to improve the efficacy of treatment.

Two times of trigeminal neuralgia resolution following hydrocephalus treatment in a patient with a high-voltage electric shock to his head: a case report and a review of the literature

Hydrocephalus has rarely been reported to be associated with trigeminal neuralgia. Here we report for the first time a case of trigeminal neuralgia associated with hydrocephalus, whose symptoms completely resolved twice after ventriculoperitoneal shunting. The patient had a high-voltage electric shock to his head, which has not been reported in a patient with ventriculoperitoneal shunt to the best of our knowledge. The possible underlying mechanism of this situation is discussed in addition to a brief review of the literature.

The selective sigma-1 receptor antagonist E-52862 attenuates neuropathic pain of different aetiology in rats

E-52862 is a selective σ1R antagonist currently undergoing phase II clinical trials for neuropathic pain and represents a potential first-in-class analgesic. Here, we investigated the effect of single and repeated administration of E-52862 on different pain-related behaviours in several neuropathic pain models in rats: mechanical allodynia in cephalic (trigeminal) neuropathic pain following chronic constriction injury of the infraorbital nerve (IoN), mechanical hyperalgesia in streptozotocin (STZ)-induced diabetic polyneuropathy, and cold allodynia in oxaliplatin (OX)-induced polyneuropathy. Mechanical hypersensitivity induced after IoN surgery or STZ administration was reduced by acute treatment with E-52862 and morphine, but not by pregabalin. In the OX model, single administration of E-52862 reversed the hypersensitivity to cold stimuli similarly to 100 mg/kg of gabapentin. Interestingly, repeated E-52862 administration twice daily over 7 days did not induce pharmacodynamic tolerance but an increased antinociceptive effect in all three models. Additionally, as shown in the STZ and OX models, repeated daily treatment with E-52862 attenuated baseline pain behaviours, which supports a sustained modifying effect on underlying pain-generating mechanisms. These preclinical findings support a role for σ1R in neuropathic pain and extend the potential for the use of selective σ1R antagonists (e.g., E-52862) to the chronic treatment of cephalic and extra-cephalic neuropathic pain.

Ophthalmic branch radiofrequency thermocoagulation for atypical trigeminal neuralgia:a case report

Background

Trigeminal neuralgia is an intense neuralgia involving facial areas supplied by trigeminal nerve. The pain is characterized by sudden onset, short persistence, sharp or lancinating. Trigeminal neuralgia commonly affects frontal areas, infraorbital or paranasal areas, mandibular areas and teeth. While Trigeminal neuralgia affecting merely the upper eyelid is rare. Here we report a case of atypical Trigeminal neuralgia confined to the upper eyelid. The patient was pain free during the follow-up period of 6 months after unusual ophthalmic branch radiofrequency thermocoagulation.

Case presentation

A 55-year-old female patient was diagnosed as primary trigeminal neuralgia involving the right upper eyelid. As the pain could not be controlled by drug therapy, peripheral nerve branch radiofrequency thermocoagulation was recommended. A combination of infratrochlear, supratrochlear and lacrimal radiofrequency thermocoagulation was implemented in this case. The point where the bridge of the nose abuts the supraorbital ridge and the point slightly above the lateral canthus along outer border of the orbit were selected respectively as the puncture sites. After positive diagnostic test, radiofrequency thermocoagulation of the above-mentioned nerve branches was performed respectively. The patient was pain free immediately after the treatment and during the follow-up period of 6 months.

Discussion

Trigeminal neuralgia is a common severe and chronic facial neuralgia which requires accurate diagnosis and effective therapy. With typical clinical symptoms, normal neurological signs, normal CT and MRI findings, the patient was diagnosed as classic trigeminal neuralgia. As the patient was drug resistant, some invasive treatments were considered. Peripheral branch neurolysis was chosen for its minimal invasiveness, convenience, low risk and not affecting further invasive treatments. According to the anatomic data and the diagnostic test results, infratrochlear, supratrochlear and lacrimal nerve were responsible, therefore, an unusual combination of infratrochlear, supratrochlear, and lacrimal radiofrequency thermocoagulation was implemented for this patient.

Conclusions

Radiofrequency thermocoagulation is an effective treatment option for trigeminal neuralgia. Peripheral branch radiofrequency thermocoagulation for trigeminal neuralgia should be considered preferentially due to its minimal invasiveness and convenience. Furthermore, as the sensory innervation of the upper eyelid is complex, the knowledge of peripheral distribution of trigeminal nerve is essential.

Botulinum neurotoxin type A in the treatment of classical Trigeminal Neuralgia (BoTN): study protocol for a randomized controlled trial

BACKGROUND

Trigeminal neuralgia is characterized by paroxysmal facial pain attacks. Adequate prophylactic drug therapy is often limited by the lack of efficacy and intolerance due to central nervous system side effects. Subcutaneous injections of botulinum toxin type A are a promising treatment option for patients with unsatisfactory response to drug therapy or neurosurgical intervention. Its effects are expected to last for at least 3 months, so it could be a potential long-term treatment. This is the study protocol of a prospective, placebo-controlled, double blind clinical trial investigating the add-on therapy of subcutaneous administration of botulinum toxin type A injections to standard treatment in therapy-refractory classical trigeminal neuralgia.

METHODS AND DESIGN

BoTN is a prospective, double blind, placebo-controlled trial with a randomized withdrawal design in which a single blind phase is followed by a double blind phase (see also Methods and design). Eligible patients with classical trigeminal neuralgia who are otherwise refractory to medical and neurosurgical treatment will receive subcutaneous injections of botulinum toxin type A into injection sites of the affected trigeminal branch. In the first phase all patients will receive botulinum toxin type A in a single blinded intervention. Twelve weeks later therapy responders will be allocated to the verum or placebo (saline) arm in a double blind, randomized manner. These injections will be performed at the same sites as the first injections. This trial will be conducted in a tertiary outpatient clinic specialized in the treatment of headache and facial pain. There will be three investigators performing the injections who are experienced in the treatment of headache and facial pain and trained in botulinum toxin type A injections.

DISCUSSION

BoTN is designed to assess the efficacy and safety of subcutaneous botulinum toxin type A injections in addition to standard prophylactic treatment in therapy-refractory trigeminal neuralgia.

TRIAL REGISTRATION NUMBER

EU Clinical Trials Register: EudraCT-No: 2014-001959-24 https://www.clinicaltrialsregister.eu/ctr-search/rest/download/trial/2014-001959-24/DE Date of trial registration 26 August 2014.

Uncommon Cause of Trigeminal Neuralgia: Tentorial Ossification over Trigeminal Notch

Ossification of the tentorium cerebelli over the trigeminal notch is rare, but it may cause compression of the trigeminal nerve, leading to trigeminal neuralgia (TN). We were unable to find any previously reported cases with radiological evaluation, although we did find one case with surgically proven ossification of the tentorium cerebelli. Here, we present a case of TN caused by tentorial ossification over the trigeminal notch depicted on magnetic resonance imaging (MRI) and computed tomography (CT).

Altered Autonomic Nervous System Reactivity to Pain in Trigeminal Neuralgia

Background: In the past two decades, there has been increasing evidence to suggest that trigeminal neuralgia (TN) may be linked to a dysfunction of the autonomic nervous system (ANS). The aim of the present study was to formally test this hypothesis by comparing the reactivity of the ANS to experimental pain in a population of TN patients and healthy controls. Methods: Twelve patients diagnosed with classical TN and 12 healthy controls participated in the study. Cardiac activity was assessed while participants were instructed to rest and again during a cold pressor test (CPT). Heart rate variability analyses were performed off-line to obtain parasympathetic (high-frequency) and sympathetic (low-frequency) indices. Results: At baseline, ANS measures did not differ between healthy controls and TN patients, and both groups showed a similar increase in heart rate during the CPT (all p values >0.05). However, TN patients showed a greater increase in cardiac sympathetic activity and a greater decrease in cardiac parasympathetic activity during CPT compared with healthy controls (all p values <0.05). Importantly, changes in sympathetic reactivity, from baseline to CPT, were negatively associated with the number of pain paroxysms experienced each day by TN patients in the preceding week (r=−.58, p<0.05). Conclusions: These results suggest that TN, like many other short-lasting, unilateral facial pain conditions, is linked to ANS alterations. Future studies are required to determine if the altered ANS response observed in TN patients is a cause or a consequence of TN pain

Intracerebroventricular opiate infusion for refractory head and facial pain

AIM: To study the risks and benefits of intracerebroventricular (ICV) opiate pumps for the management of benign head and face pain.

METHODS: SSix patients with refractory trigeminal neuralgia and/or cluster headaches were evaluated for implantation of an ICV opiate infusion pump using either ICV injections through an Ommaya reservoir or external ventricular drain. Four patients received morphine ICV pumps and two patientS received a hydromorphone pump. Of the Four patients with morphine ICV pumps, one patient had the medication changed to hydromorphone. Preoperative and post-operative visual analog scores (VAS) were obtained. Patients were evaluated post-operatively for a minimum of 3 mo and the pump dosage was adjusted at each outpatient clinic visit according to the patient’s pain level.

RESULTS: All 6 patients had an intracerebroventricular opiate injection trial period, using either an Ommaya reservoir or an external ventricular drain. There was an average VAS improvement of 75.8%. During the trial period, no complications were observed. Pump implantation was performed an average of 3.7 wk (range 1-7) after the trial injections. After implantation, an average of 20.7 ± 8.3 dose adjustments were made over 3-56 mo after surgery to achieve maximal pain relief. At the most recent follow-up (26.2 mo, range 3-56), VAS scores significantly improved from an average of 7.8 ± 0.5 (range 6-10) to 2.8 ± 0.7 (range 0-5) at the final dose (mean improvement 5.0 ± 1.0, P < 0.001). All patients required a stepwise increase in opiate infusion rates to achieve maximal benefit. The most common complications were nausea and drowsiness, both of which resolved with pump adjustments. On average, infusion pumps were replaced every 4-5 years.

CONCLUSION: These results suggest that ICV delivery of opiates may potentially be a viable treatment option for patients with intractable pain from trigeminal neuralgia or cluster headache.

Surgical Management of Trigeminal Neuralgia

BACKGROUND:

Trigeminal neuralgia is a relatively common neurosurgical pathology with multiple management options. Microvascular decompression (MVD) is nonablative and is considered the gold standard. However, stereotaxic radiosurgery (SRS) and percutaneous stereotaxic rhizotomy (PSR) are 2 noninvasive but ablative options that have rapidly gained support.

OBJECTIVE:

To use Medicare claims data in conjunction with a literature review to assess the usage, effectiveness, and cost-effectiveness of the 3 different invasive treatments for trigeminal neuralgia.

METHODS:

All of the claims of trigeminal neuralgia treatment were extracted from the 2011 5% Inpatient and Outpatient Limited Data Set. Current Procedural Terminology, 4th Edition/International Classification of Diseases, Ninth Revision codes for the 3 different surgical treatment modalities were used to further classify these claims. Kaplan-Meier survival curves in key articles were used to calculate quality-adjusted life years and cost-effectiveness for each procedure.

RESULTS:

A total of 1582 claims of trigeminal neuralgia were collected. Ninety-four (6%) patients underwent surgical intervention. Forty-eight (51.1%) surgical patients underwent MVD, 39 (41.5%) underwent SRS, and 7 (7.4%) underwent PSR. The average weighted costs for MVD, SRS, and PSR were $;40 434.95, $;38 062.27, and $;3910.64, respectively. The quality-adjusted life years were 8.2 for MVD, 4.9 for SRS, and 6.5 for PSR. The cost per quality-adjusted life year was calculated as $;4931.1, $;7767.8, and $;601.64 for MVD, SRS, and PSR, respectively.

CONCLUSION:

This study shows that the most frequently used surgical management of trigeminal neuralgia is MVD, followed closely by SRS. PSR, despite being the most cost-effective, is by far the least utilized treatment modality.

An observational trial to investigate the efficacy and tolerability of levetiracetam in trigeminal neuralgia

OBJECTIVE

To explore the efficacy and tolerability of levetiracetam in medical treatment of trigeminal neuralgia.

BACKGROUND

Antiepileptic drugs (AEDs) are considered as first-line treatment for trigeminal neuralgia, although their use is often limited due to incomplete efficacy and tolerability. Newer AEDs with improved safety profile may be useful in this disorder.

METHODS

Patients suffering from trigeminal neuralgia (either primary or secondary) refractory to previous treatments were recruited to be treated with levetiracetam (3-4 g/day) for 16 weeks as add-on therapy, after a 2-week baseline period. Rescue medication was allowed in both the baseline and treatment phases. The primary efficacy measure was the number of attacks per day. The patients' efficacy evaluation, the patients' global evaluation for both safety and efficacy, changes in the Hamilton Depression Scale, the Hamilton Anxiety Scale, and the Quality of Life Measure Short Form-36 were secondary parameters.

RESULTS

Twenty-three patients were included in the analysis. After treatment and compared to the baseline phase, the number of daily attacks decreased by 62.4%. All secondary parameters changed significantly with the exception of the Quality of Life Measure Short Form-36 score. Seven patients withdrew from the study. Five patients (21.7%) reported side effects and 2 withdrew.

CONCLUSIONS

Levetiracetam may be effective and safe in trigeminal neuralgia treatment. Confirmation in a randomized controlled study is needed.

Cranial neuralgias

This article describes the clinical findings of cranial neuralgias, such as trigeminal neuralgia, glossopharyngeal neuralgia, nervus intermedius neuralgia, and others, and postherpetic neuralgia. Pathophysiology of these neuralgias, diagnostic methods, and treatment are also discussed. This information will enable the dentist to diagnose patients who have these rare conditions.

A mechanism-based classification of pain in multiple sclerosis

Pharmacological treatment of pain in multiple sclerosis (MS) is challenging due to the many underlying pathophysiological mechanisms. Few controlled trials show adequate pain control in this population. Emerging evidence suggests that pain might be more effectively classified and treated according to symptoms and underlying mechanisms. The new mechanism-based classification we propose here distinguishes nine types of MS-related pain: trigeminal neuralgia and Lhermitte's phenomenon (paroxysmal neuropathic pain due to ectopic impulse generation along primary afferents), ongoing extremity pain (deafferentation pain secondary to lesion in the spino-thalamo-cortical pathways), painful tonic spasms and spasticity pain (mixed pains secondary to lesions in the central motor pathways but mediated by muscle nociceptors), pain associated with optic neuritis (nerve trunk pain originating from nervi nervorum), musculoskeletal pains (nociceptive pain arising from postural abnormalities secondary to motor disorders), migraine (nociceptive pain favored by predisposing factors or secondary to midbrain lesions), and treatment-induced pains. Identification of various types of MS-related pain will allow appropriate targeted pharmacological treatment and improve clinical practice.

Trigeminal neuralgia and persistent idiopathic facial pain

Trigeminal neuralgia (TN) and persistent idiopathic facial pain (PIFP) are two of the most puzzling orofacial pain conditions and affected patients are often very difficult to treat. TN is characterized by paroxysms of brief but severe pain followed by asymptomatic periods without pain. In some patients a constant dull background pain may persist. This constant dull pain sometimes makes the distinction from PIFP difficult. PIFP is defined as continuous facial pain, typically localized in a circumscribed area of the face, which is not accompanied by any neurological or other lesion identified by clinical examination or clinical investigations. The pain usually does not stay within the usual anatomic boundaries of the trigeminal nerve distribution and is a diagnosis of exclusion. Epidemiologic evidence on TN, and even more so on PIFP, is quite scarce, but generally both conditions are considered to be rare diseases. The etiology and underlying pathophysiology of TN, and more so PIFP, remain unknown. Treatment is based on only few randomized controlled clinical trials and insufficiently evaluated surgical procedures.

Treatment of refractory trigeminal neuralgia with intravenous phenytoin

PURPOSE

The case of a patient who was successfully treated with i.v. phenytoin for an acute exacerbation of refractory trigeminal neuralgia (TN) is reported.

SUMMARY

A 77-year-old, 87-kg Caucasian man with a 12-year history of right-sided, classical TN was admitted for an acute exacerbation of TN refractory to pharmacologic treatment with carbamazepine, baclofen, hydrocodone-acetaminophen, tramadol, hydromorphone, and gabapentin. His medical history included atrial fibrillation, peripheral vascular disease, benign prostatic hyperplasia, and chronic ataxia secondary to antibiotic therapy in the 1970s. His outpatient medications included carbamazepine, warfarin, ergocalciferol, and saw palmetto. A 15-mg/kg dose of i.v. phenytoin sodium (1300 mg on the basis of total body weight) was recommended by neurology consultants. Because of potential adverse reactions related to high serum phenytoin concentrations and rapid infusion rates (e.g., hypotension, ataxia, nausea, vomiting, apnea, nystagmus), the patient's age, the baseline presence of atrial fibrillation and ataxia, and the fact that seizures were not being treated, the clinical pharmacist recommended dividing the 1300-mg dose into two 650-mg doses separated by four hours, with each infused at 25 mg/min; this suggestion was accepted. The patient's pain score dropped from a self-rated 12/10 to 2/10 after the first infusion and to 1/10 after completion of the second infusion. The patient's blood pressure and heart rate were monitored via telemetry every five minutes during both infusions. No adverse events were noted.

CONCLUSION

Phenytoin sodium 15 mg/kg i.v. divided into two doses separated by four hours was safe and effective in treating an acute exacerbation of refractory TN.

Ocular and orbital pain for the headache specialist

Ocular pain is most commonly associated with redness and inflammation; however, eye pain can also occur in the absence of grossly visible pathology. Pain in the quiet eye can be the first sign of a number of threatening conditions. Many of these conditions such as intermittent angle closure glaucoma, carotid artery dissection, idiopathic intracranial hypertension, and giant cell arteritis can lead to permanent vision loss or blindness. In this review, ocular history and examination techniques are summarized. The article also reviews pertinent ocular, orbital, referred, and other causes of eye pain in the quiet eye. The neurologist and headache specialist should recognize when consultation with an ophthalmologist is necessary.