Trigeminal neuralgia: for one nerve a multitude of treatments

"Status trigeminal neuralgia": Analysis of 39 cases and proposal for diagnostic criteria

OBJECTIVE

The aim of this descriptive study was to propose diagnostic criteria for acute exacerbation of trigeminal neuralgia (TN) based on the analysis of retrospective cases.

BACKGROUND

TN is a rare and extremely painful condition whose evolution can be punctuated by major exacerbations, leading to significant functional impairment. Several denominations are used for these exacerbations: "acute exacerbation", "status of trigeminal neuralgia", and "status trigeminus". There is currently no clinical definition of this state. In this manuscript, we used the term "status trigeminal neuralgia" (STN).

METHODS

We conducted a retrospective study, in a tertiary care specialist headache center, in France. Patients were selected from January 2015 to October 2022, with the French translation of the keyword "STN", in the medical records (outpatients) or the codage for trigeminal neuralgia (inpatients). Additional cases of STN were prospectively recruited from October 2022 to February 2023. We analyzed the clinical and paraclinical data of these patients.

RESULTS

Thirty-nine patients presenting with STN were included. There was a preponderance of women (64%) with 24 cases of classic TN (62%) and 15 cases of secondary TN (38%). Concerning STN, 39 episodes were described. Pain was very severe in all patients. Cranial autonomic signs were present in 23% of cases. Pain extended beyond the usual territory in 44% of cases. A continuous pain background was present in 35% of cases. With regard to triggering factors, paroxysms of facial pain were triggered by eating (97% of patients), speaking (90%) or drinking (62% of patients). Repercussions on weight, hydration, or mood disorders were observed in 67%, 56% and 59% of the cases, respectively.

CONCLUSION

STN is a rare clinical presentation of TN. We proposed criteria and a new denomination for this condition.

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.

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.

Trigeminal Neuralgia Secondary to Herpes Simplex Virus Type 1 Infection Treated With Oral Acyclovir

Trigeminal neuralgia (TN) is characterized by episodic electric, shock-like facial pain. Though often idiopathic, herpes simplex virus type 1 (HSV-1) reactivation can rarely cause symptomatic TN. We report the case of a 30-year-old woman who developed oral HSV-1 lesions followed by right-sided TN pain. MRI of the brain did not reveal neurovascular compression. TN pain completely resolved with oral acyclovir treatment alone, without anticonvulsants. This highlights the importance of considering atypical etiologies such as HSV-1 reactivation in TN evaluation. Early antiviral therapy may treat underlying inflammation and provide sustained symptom relief in HSV-associated TN.

Pulsed Radiofrequency for the Treatment of Trigeminal Neuralgia

PURPOSE OF REVIEW

Trigeminal neuralgia is a sudden, unilateral, stabbing pain in the distribution of one or more branches of the fifth cranial nerve, with an overall prevalence ranging between 0.03 and 0.3%. While conservative treatments may offer temporary relief, many patients experience chronic headaches associated with their neuralgia. Invasive treatments are available for patients with intractable neuralgia; however, they may cause permanent tissue damage and often do not provide relief. This article examines pulsed radiofrequency (PRF) ablation (RFA) of the trigeminal nerve as a minimally invasive procedure that offers a promising alternative to invasive procedures for relief of trigeminal neuralgia while minimizing tissue damage.

RECENT FINDINGS

Efficacy of PRF and RFA in treating trigeminal neuralgia has been studied before, but literature lacks large size studies. The results of this retrospective study indicate that PRF can be used as a safe and effective treatment for patients suffering from trigeminal neuralgia that is refractory to conservative measures.

Pain Following Endoscopic Foreheadplasty Surgery in Women

BACKGROUND

Endoscopic foreheadplasty surgery (EFS) is a common procedure; however, little has been reported about the nature or treatment of postoperative headache pain and associated symptoms.

OBJECTIVES

The objective of this study was to describe the intensity, quality, location, and duration of headache pain in women following EFS. We also compared post-EFS symptoms with migraine, described medication use and efficacy, and measured emotional and functional outcomes.

METHODS

This descriptive study used an observational repeated-measures design. Forty-two women (mean [standard deviation] age, 59.0 [7.9] years) undergoing EFS were prospectively recruited from 12 private cosmetic practices in 3 California counties. Telephone interviews with the Acute Short-Form 12v2 and the Headache Pain Questionnaire were conducted on postoperative days (POD) 1, 3, 7, and 30.

RESULTS

On POD 1, 93% reported at least moderate pain and 64% severe pain. Severe pain was characterized as throbbing (71%), sharp (53%), dull (76%), exploding (41%), imploding (53%), continuous (53%), or intermittent (41%) on POD 1. Moderate pain was most frequent on POD 3 (21%) compared to POD 1 (19%), 7 (12%) and 30 (12%). Mild pain predominated on POD 3 (40%) and 7 (40%), with 20% remaining on POD 30. The majority (79%) of post-EFS symptoms included light sensitivity and nausea, and therefore met most International Classification of Headache Disorders criteria for migraine. Analgesic use provided inconsistent relief. Functional and emotional status did not return to baseline throughout the 30-day postoperative period.

CONCLUSIONS

Immediately following EFS, most women experience moderate to severe headache pain, despite use of medications. Pain persists in many patients for up to 1 month. Headache is associated with migraine symptoms, including light sensitivity and nausea.

LEVEL OF EVIDENCE: 4

Efficacy and complications of microvascular decompression in patients over 70 years with trigeminal neuralgia

OBJECTIVE

Treatment of choice for trigeminal neuralgia (TN) by neurovascular conflict in case of failure of medical treatment is microvascular decompression (MVD). It is a safe and effective technique in the short and long term. But what about older patients who are considered more fragile anesthetically and surgically? Our Objective is to demonstrate the efficacy and complication rate of microvascular decompression (MVD) for older and younger patients with trigeminal neuralgia (TN) due to neurovascular conflict.

METHODS

102 patients with TN due to neurovascular conflict were included (June 2005-December 2016) in a single Regional hospital. 25 were included in the group composed of ≥ 70-year-old patients (G1), while 77 were included in the < 70-year-old group (G2). The patients were operated on by the same surgical team using a retro-sigmoid approach to access the neurovascular conflict. The epidemiologic, clinical, anesthetic, and surgical data were extracted.

RESULTS

The immediate efficacy of surgical treatment (BNI pain intensity = I) was 96% in G1 and 96.10% in the G2 group (p = 0.71). At 3-year follow-up, the efficacy rate was 89% and 86%, respectively (p = 0.93). At 5 years, it was 92% and 92% (p = 0.98). Complication rates were comparable between the two groups (20% versus 27%; p = 0.47) and no deaths occurred despite the fact that G1 group had worst preoperative anesthetic score (ASA-NYHA).

CONCLUSION

MVD is a durable procedure in patients over 70 years of age diagnosed with essential TN. The complication rate and immediate-, medium-, and long-term efficacy were similar to those of younger patients.

A Preliminary Study of the Efficacy of Transcranial Direct Current Stimulation in Trigeminal Neuralgia

The purpose of this study is to assess the efficacy of transcranial direct current stimulation (tDCS) in patients with treatment-refractory trigeminal neuralgia (TN) and examine the utility of neuroimaging methods in identifying markers of such efficacy. Six patients with classical TN refractory to maximal medical treatment, underwent tDCS (three cases inhibitory/cathodic and three cases excitatory/anodic stimulation). All patients underwent pre- and posttreatment functional magnetic resonance imaging (fMRI) during block-design tasks (i.e., Pain, Pain + tDCS, tDCS) as well as single-shell diffusion MRI (dMRI) acquisition. The precise locations of tDCS electrodes were identified by neuronavigation. Five therapeutic tDCS sessions were carried out for each patient with either anodic or cathodic applications. The Numeric Rating Scale of pain (NRS) and the Headache Disability Index (HDI) were used to score the subjective efficacy of treatment. Altered activity of regional sites was identified by fMRI and associated changes in the spinothalamocortical sensory tract (STCT) were measured by the dMRI indices of fractional anisotropy (FA) and mean diffusivity (MD). Fiber counts of the bilateral trigeminal root entry zone (REZ) were performed as an added measure of fiber loss or recovery. All patients experienced a significant reduction in pain scores with a substantial decline in HDI (P value < 0.01). Following a course of anodic tDCS, the ipsilateral caudate, globus pallidus, somatosensory cortex, and the contralateral globus pallidus showed a significantly attenuated activation whereas cathodic tDCS treatment resulted in attenuation of the thalamus and globus pallidus bilaterally, and the somatosensory cortex and anterior cingulate gyrus contralaterally. dMRI analysis identified a substantial increase (>50%) in the number of contralateral sensory fibers in the STCT with either anodic or cathodic tDCS treatment in four of the six patients. A significant reduction in FA (>40%) was observed in the ipsilateral REZ in the posttreatment phase in five of the six patients. Preliminary evidence suggests that navigated tDCS presents a promising method for alleviating the pain of TN. Different patterns of activation manifested by anodic and cathodic stimulation require further elaboration to understand their implication. Activation and attenuation of responses at various sites may provide further avenues for condition treatment.

Leveraging high-resolution 7-tesla MRI to derive quantitative metrics for the trigeminal nerve and subnuclei of limbic structures in trigeminal neuralgia

BACKGROUND

Trigeminal Neuralgia (TN) is a chronic neurological disease that is strongly associated with neurovascular compression (NVC) of the trigeminal nerve near its root entry zone. The trigeminal nerve at the site of NVC has been extensively studied but limbic structures that are potentially involved in TN have not been adequately characterized. Specifically, the hippocampus is a stress-sensitive region which may be structurally impacted by chronic TN pain. As the center of the emotion-related network, the amygdala is closely related to stress regulation and may be associated with TN pain as well. The thalamus, which is involved in the trigeminal sensory pathway and nociception, may play a role in pain processing of TN. The objective of this study was to assess structural alterations in the trigeminal nerve and subregions of the hippocampus, amygdala, and thalamus in TN patients using ultra-high field MRI and examine quantitative differences in these structures compared with healthy controls.

METHODS

Thirteen TN patients and 13 matched controls were scanned at 7-Tesla MRI with high resolution, T1-weighted imaging. Nerve cross sectional area (CSA) was measured and an automated algorithm was used to segment hippocampal, amygdaloid, and thalamic subregions. Nerve CSA and limbic structure subnuclei volumes were compared between TN patients and controls.

RESULTS

CSA of the posterior cisternal nerve on the symptomatic side was smaller in patients (3.75 mm2) compared with side-matched controls (5.77 mm2, p = 0.006). In TN patients, basal subnucleus amygdala volume (0.347 mm3) was reduced on the symptomatic side compared with controls (0.401 mm3, p = 0.025) and the paralaminar subnucleus volume (0.04 mm3) was also reduced on the symptomatic side compared with controls (0.05 mm3, p = 0.009). The central lateral thalamic subnucleus was larger in TN patients on both the symptomatic side (0.033 mm3) and asymptomatic side (0.035 mm3), compared with the corresponding sides in controls (0.025 mm3 on both sides, p = 0.048 and p = 0.003 respectively). The inferior and lateral pulvinar thalamic subnuclei were both reduced in TN patients on the symptomatic side (0.2 mm3 and 0.17 mm3 respectively) compared to controls (0.23 mm3, p = 0.04 and 0.18 mm3, p = 0.04 respectively). No significant findings were found in the hippocampal subfields analyzed.

CONCLUSIONS

These findings, generated through a highly sensitive 7 T MRI protocol, provide compelling support for the theory that TN neurobiology is a complex amalgamation of local structural changes within the trigeminal nerve and structural alterations in subnuclei of limbic structures directly and indirectly involved in nociception and pain processing.

Does the Surgical Intervention for Trigeminal Neuralgia Refractory to Pharmacotherapy Improve Quality-of-Life? - A Systematic Review

PURPOSE

Trigeminal neuralgia (TN) refractory to pharmacotherapy requires surgical interventions which vary from percutaneous procedure to microvascular decompression (MVD). The aim of the systematic review is to find evidence for the surgical treatment for TN with high success rate and low complications which improves the quality-of-life (QOL).

METHODS

A systematic literature search was made on published studies from MEDLINE, SCOPUS, Science direct, and Cochrane Library databases that report the available surgical treatment for TN up to March 2020 and studies referred in the selected papers. Relevant studies were selected based on predefined eligibility criteria. The primary outcome measured was success rate, pain relief and secondary outcome measured was QOL, recurrence and complication rate.

RESULTS

Ten studies with a sum of 11,154 individuals were included in this qualitative analysis. Seven studies compared MVD whereas 4 studies compared Gamma knife radiosurgery with other techniques like percutaneous balloon compression, percutaneous glycerol rhizotomy etc. The result showed that MVD has a considerable higher rate of initial pain-free outcomes (96.6%) followed by Gamma knife radiosurgery (96.2%), cryotherapy (95.4%), percutaneous balloon compression (87%), percutaneous glycerol rhizotomy (85%) and the lowest rate of cohorts who were never pain-free (1.7%).QOL was improved to 100% as a result of pain relief which was evaluated in only 2 studies . Overall the recurrence rate was 0.45 to 52%. MVD has lower rate of long-term recurrence 0.45 and 6.1% for 2 years and 8 years, respectively, and cryotherapy has the highest rate of 52% at 6 months.

CONCLUSION

Outcomes of the literature search showed that it lacks the knowledge to generally support 1 or the other treatment. Each type of TN requires individualized protocols to treat based on pain response which ultimately improve the QOL. We also propose there should be more reliable data reporting by using a universally acceptable pain scale for better analysis of treatment outcome.

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.

Trigeminal Neuralgia Crisis - Intravenous Phenytoin as Acute Rescue Treatment

OBJECTIVE

The aim of this retrospective cohort study was to analyze responses to intravenous (IV) phenytoin (PHT) for trigeminal neuralgia (TN) crisis in a group of patients treated at our institution.

BACKGROUND

TN is one of the most common causes of facial pain. Its treatment relies on preventive therapy with either carbamazepine or oxcarbazepine. During severe pain episodes, patients may be unable to eat, drink, or even swallow oral medication, requiring in-hospital treatment. There is scarce evidence to support IV medication use for TN, making management of this condition difficult.

METHODS

We reviewed clinical records of patients with TN crisis consulting the emergency department at a tertiary neurological referral center in Buenos Aires, Argentina, treated with IV PHT as analgesic strategy, and with at least 1-month posttreatment follow-up. Demographic features, magnetic resonance imaging findings, and therapeutic management were analyzed.

RESULTS

Thirty-nine patients with TN were included, 18 (46.2%) receiving IV PHT more than once (total number of infusions administered, 65). Immediate pain relief was observed in 89.2% (58/65) and 15.4% (10/65) presented side effects.

CONCLUSIONS

We recommend IV PHT as acute rescue treatment in TN crisis.

Pain Neurology

Pain is often the initial complaint for which patients seek medical care, presenting both a diagnostic and therapeutic challenge to the primary care provider. The appreciation of pain is not merely the result of abnormal sensory stimulation causing an unpleasant sensation but rather a combination of the recognition of the somatic discomfort in association with an emotional response to that discomfort. The perception of pain and the extent of distress and disability can vary depending on previous experience, cultural background, situational factors, and comorbid psychiatric disease. Though acute pain is usually the result of tissue damage, this is not always the case, as evidenced by primary headache disorders. Chronic pain may be the result of an injury, irreversible underlying disease, or clinical conditions such as fibromyalgia for which the mechanism remains unclear. Treatment of the underlying cause will usually effect a resolution or improvement in the pain, but when the discomfort persists, a consultation with a neurologist or pain management specialist should be considered.

Factors affecting the therapeutic effect of botulinum toxin A on trigeminal neuralgia: A follow-up retrospective study of 152 patients

Botulinum toxin A (BTX-A) is a promising therapeutic modality against trigeminal neuralgia (TN) with certain controversies pertaining to its application. To provide further information on factors influencing the treatment outcomes of BTX-A, a retrospective study with 152 patients with TN treated with BTX-A was performed. The starting time and duration of the therapeutic effect, as well as side effects, of BTX-A in the treatment of TN were analyzed by sex, age, course of disease, number of branches and injected dose. A total of 136 patients exhibited symptom improvement within 2 weeks following BTX-A treatment as evaluated using a visual analog scale (VAS). The effect of BTX-A was sustained throughout the initial 6 months of the follow-up and was demonstrated to persist for as long as 28 months. Female sex, short disease course and high injection dose (>70 units) were associated with lower long-term VAS scores. Patients receiving short-term medium-(50–70 units) or high-dose injections were more likely to be completely cured. Patients with a median disease course (1–10 years) or multiple branches were more likely to exhibit facial asymmetry. Based on the stratified analysis, female patients with a median disease course (1–10 years) exhibited a higher incidence of side effects and male patients achieved better treatment outcomes with high BTX-A doses. BTX-A effectively alleviated patients with TN in both short or long term, although the treatment efficacy may depend on patient characteristics.

Multivariate pattern classification of brain white matter connectivity predicts classic trigeminal neuralgia

Trigeminal neuralgia (TN) is a severe form of chronic facial neuropathic pain. Increasing interest in the neuroimaging of pain has highlighted changes in the root entry zone in TN, but also group-level central nervous system gray and white matter (WM) abnormalities. Group differences in neuroimaging data are frequently evaluated with univariate statistics; however, this approach is limited because it is based on single, or clusters of, voxels. By contrast, multivariate pattern analyses consider all the model's neuroanatomical features to capture a specific distributed spatial pattern. This approach has potential use as a prediction tool at the individual level. We hypothesized that a multivariate pattern classification method can distinguish specific patterns of abnormal WM connectivity of classic TN from healthy controls (HCs). Diffusion-weighted scans in 23 right-sided TN and matched controls were processed to extract whole-brain interregional streamlines. We used a linear support vector machine algorithm to differentiate interregional normalized streamline count between TN and HC. This algorithm successfully differentiated between TN and HC with an accuracy of 88%. The structural pattern emphasized WM connectivity of regions that subserve sensory, affective, and cognitive dimensions of pain, including the insula, precuneus, inferior and superior parietal lobules, and inferior and medial orbital frontal gyri. Normalized streamline counts were associated with longer pain duration and WM metric abnormality between the connections. This study demonstrates that machine-learning algorithms can detect characteristic patterns of structural alterations in TN and highlights the role of structural brain imaging for identification of neuroanatomical features associated with neuropathic pain disorders.

The Neuralgias

PURPOSE OF REVIEW

Neuralgias are characterized by pain in the distribution of a cranial or cervical nerve. Typically, they are brief, paroxysmal, painful attacks, although continuous neuropathic pain may occur. The most commonly encountered conditions are trigeminal, postherpetic, and occipital neuralgia. Less common neuralgias include glossopharyngeal, superior laryngeal, auriculotemporal, and nervus intermedius neuralgia, among others. The approach to diagnosis and treatment of this group of disorders is reviewed.

RECENT FINDINGS

Recent guidelines of medication administration, the use of botulinum toxin, and more targeted procedures have improved treatment of neuralgias. Patients who present with neuralgias should have imaging studies to investigate for structural abnormalities unless the etiology is apparent. Management of both common and rare neuralgias can be challenging and is best guided by the most recent available evidence.

Botulinum toxin in the management of head and neck disorders

Botulinum toxin is a polypeptide protoxin synthesized by Clostridium botulinum that results in localized reduction of muscle activity by inhibiting acetylcholine release at the neuromuscular junction. In 2004, the US Food and Drug Administration approved its application in the treatment of various medical conditions, such as facial wrinkles, strabismus, cervical dystonia, blepharospasm, and hyperhidrosis. Later, its application extended to improving dental esthetics and gummy smile. It was found to be a safe and effective alternative to medical therapy to treat various head and neck disorders that have a neurologic component. In this review, we will highlight the mechanism of action and therapeutic benefits of botulinum toxin in the management of head and neck disorders.

Resveratrol suppresses glial activation and alleviates trigeminal neuralgia via activation of AMPK

Background

Glial activation and neuroinflammation in the spinal trigeminal nucleus (STN) play a pivotal role in the genesis and maintenance of trigeminal neuralgia (TN). Resveratrol, a natural compound from grape and red wine, has a potential anti-inflammatory effect. We hypothesized that resveratrol could significantly suppress neuroinflammation in the STN mediated by glial activation and further relieve TN. In this study, we evaluated whether resveratrol could alleviate trigeminal allodynia and explore the mechanism underlying the antinociceptive effect of resveratrol.

Methods

Animals were orally injected with resveratrol after chronic constriction injury (CCI) of the infraorbital nerve. Mechanical thresholds of the affected whisker pad were measured to assess nociceptive behaviors. The STN was harvested to quantify the changing levels of p-NR1, p-PKC, TNF-α, and IL1-β by western blotting and detect the expression of calcitonin gene-related peptide (CGRP) and c-Fos by immunofluorescence. Glial activation was observed by immunofluorescence and western blotting. Mitogen-activated protein kinase (MAPK) phosphorylation in vivo and in vitro was examined by western blotting.

Results

We found that resveratrol significantly attenuated trigeminal allodynia dose-dependently and decreased the increased expression of CGRP and c-Fos in the STN. Additionally, resveratrol showed an inhibitory effect on CCI-evoked astrocyte and microglia activation and reduced production of pro-inflammatory cytokines in the STN. Furthermore, the antinociceptive effect of resveratrol was partially mediated by reduced phosphorylation of MAP kinases via adenosine monophosphate-activated protein kinase (AMPK) activation.

Conclusions

AMPK activation in the STN glia via resveratrol has utility in the treatment of CCI-induced neuroinflammation and further implicates AMPK as a novel target for the attenuation of trigeminal neuralgia.

Botulinum Toxin Type a as a Therapeutic Agent against Headache and Related Disorders

Botulinum neurotoxin A (BoNT/A) is a toxin produced by the naturally-occurring Clostridium botulinum that causes botulism. The potential of BoNT/A as a useful medical intervention was discovered by scientists developing a vaccine to protect against botulism. They found that, when injected into a muscle, BoNT/A causes a flaccid paralysis. Following this discovery, BoNT/A has been used for many years in the treatment of conditions of pathological muscle hyperactivity, like dystonias and spasticities. In parallel, the toxin has become a “glamour” drug due to its power to ward off facial wrinkles, particularly frontal, due to the activity of the mimic muscles. After the discovery that the drug also appeared to have a preventive effect on headache, scientists spent many efforts to study the potentially-therapeutic action of BoNT/A against pain. BoNT/A is effective at reducing pain in a number of disease states, including cervical dystonia, neuropathic pain, lower back pain, spasticity, myofascial pain and bladder pain. In 2010, regulatory approval for the treatment of chronic migraine with BoNT/A was given, notwithstanding the fact that the mechanism of action is still not completely elucidated. In the present review, we summarize experimental evidence that may help to clarify the mechanisms of action of BoNT/A in relation to the alleviation of headache pain, with particular emphasis on preclinical studies, both in animals and humans. Moreover, we summarize the latest clinical trials that show evidence on headache conditions that may obtain benefits from therapy with BoNT/A.

Application of Antidromic Conduction Monitoring in Ganglion Radiofrequency Thermocoagulation for Locating Trigeminal Branches in Trigeminal Neuralgia

OBJECTIVE

The aim of this study was to investigate whether antidromic conduction monitoring (ACM) can be utilized to map the trigeminal system under sedation as a potential substitute for subjective paresthesia description (SPD) during percutaneous ganglion radiofrequency thermocoagulation (PGRT).

METHODS

Eighty-two patients with 152 pain divisions of trigeminal neuralgia (TN) were treated by computed tomography (CT)-guided PGRT. After the puncture needle entered the foramen ovale (FO), sensory and motor stimulation were applied to locate the pain division. And the corresponding voltage values were recorded by patients' SPD. In the following, the proper location was certified by ACM. The corresponding earliest waves and voltage values in the identified trigeminal branch were also recorded to outline a comparison between two methods.

RESULTS

The correlation of ACM and patients' SPD with voltage at ≤ 0.5 V was statistically significant (P < 0.05, r = 0.159; Spearman's rank correlation analysis). Although ACM and SPD showed weak correlation, as their interclass correlation coefficient was significant (F = 1.868, P < 0.01) with coefficient of internal consistency. Moreover, the two methods had consistency. Kruskal-Wallis test showed that ophthalmic (V1), maxillary (V2), and mandibular (V3) divisions had significant differences for test sensitivity (H = 15.945, P < 0.01). For comparison of sensitivities with ACM, V3 was most sensitive followed by V2 and then V1.

CONCLUSION

ACM could potentially substitute for SPD of the paresthesias intra-operatively, enabling greater specificity and eliminating the need to interrupt the administration of anesthetic. These improvements would increase patient satisfaction and practitioner efficiency and accuracy.

The Effect of Low-level Laser Therapy on Trigeminal Neuralgia: A Review of Literature

The effect of low intensity laser radiation in the treatment of acute and chronic pain is now established in many studies. Tri-geminal neuralgia is a pain passes through nerve's branches and its trigger is located in skin or mucosa that could lead to pain with a trigger stimulus. The pain involved branches of trigeminal nerve that sometimes has patients to seek the treatment for several years. Nowadays different treatments are used for relief of pain that most of them cause tolerance and various side effects. This paper reviews and summarizes scientific papers available in English literature publishedin PubMed, Scopus, Science Direct, Inter science, and Iran Medex from 1986 until July 2011 about the effect of these types of lasers on trigeminal neuralgia which is one of the most painful afflictions known. In different studies, the effect of laser therapy has been compared with placebo irradiation or medicinal and surgical treatment modalities. Low-level laser therapy (LLLT) is a treatment strategy which uses a single wavelength light source. Laser radiation and monochromatic light may alter cell and tissue function. However, in most studies laser therapy was associated with significant reduction in the intensity and frequency of pain compared with other treatment strategies, a few studies revealed that between laser and placebo group there was not any significant difference according to the analgesic effect. Low-level laser therapy could be considered in treatment of trigeminal neuralgia without any side effects.

Therapeutic efficacy and safety of botulinum toxin type A in trigeminal neuralgia: a systematic review

Trigeminal neuralgia is a common disorder caused mainly by compression of the trigeminal nerve root by an overlying blood vessel. Pharmacotherapy and surgery are ineffective or unsuitable in many patients. Therefore, other therapeutic modalities have been tried, including injection of botulinum toxin type A (BTX-A). This study aims to systematically review the therapeutic efficacy and safety of BTX-A in trigeminal neuralgia. PubMed, EMBASE, Cochrane Library Clinical Trials and Web of Science from January 1966 to March 2013 were searched with the terms of “botulinum toxin” AND “trigeminal neuralgia”, and references of related articles were traced. Data on the efficacy and safety of BTX-A in this disorder were extracted and analyzed by at least 2 reviewers. Data for individual studies were reported, and pooled data were analyzed if appropriate. Five prospective studies and one double-blind, randomized, placebo-controlled study were identified. Response was achieved in approximately 70-100% of patients, and the mean pain intensity and frequency were reduced by approximately 60-100% at 4 weeks after treatment in most studies. Major adverse events were not reported. Available studies show BTX-A may be effective in treatment of trigeminal neuralgia. However, well-designed randomized, controlled, double-blinded trial is still lacking. Future BTX-A treatment studies on optimal dose, duration of the therapeutic efficacy, common AEs, and the time and indications for repeat injection would be promising.

A closer look to botulinum neurotoxin type A-induced analgesia

Chronic pain indicates a type of pain that lasts over time and is accompanied by diagnostic and therapeutic difficulties. It follows that treatment failures are common and patients roam from doctor to doctor in search of an effective care program. So there is an urgent need for long-acting and effective therapeutics to alleviate symptoms of the varied forms of chronic pain. During the past few years, a good success has been achieved with a derivative of a neurotoxin. It has been shown that administration of this toxin can block the release of neurotransmitters and pain mediators. Botulinum neurotoxin type A (BoNT/A) is well known as a treatment for neuromuscular conditions such as dystonia and spasticity. However, the clinical application for BoNT/A has continued to expand. Its analgesic effect has been used in clinical practice with satisfactory results. This review provides an introduction of a hypothesis for the mechanism by which BoNT/A eases chronic pain. It also summarizes the clinical therapeutic effects of BoNT/A in different types of chronic pain and its potential prospects.

Duration of remission phase of 36 Korean patients with glossopharyngeal neuralgia

BACKGROUND

Glossopharyngeal neuralgia has the characteristic of a long remission phase between the pain attack phases. Although the concept of remission is very important for the treatment of patients with glossopharyngeal neuralgia, due to the rarity of the disease, clear statistical studies on the remission phase for glossopharyngeal neuralgia are almost non-existent.

METHODS

Previous chart reviews and phone interviews were conducted on a total of 38 patients. Among these study subjects, two patients were excluded because of their known secondary glossopharyngeal neuralgia from their brain tumors. Hence, the average duration of remission was investigated on 36 patients with idiopathic glossopharyngeal neuralgia.

RESULTS

For the 27 patients who experienced their first remission, the average duration of the remission was 3.1 years. Among them, the average duration of the second remission of the 17 patients was 2.5 years, and for 4 patients who experienced a third remission, the average duration of the remission phase was 1.9 years.

CONCLUSIONS

The difference in the mean duration of the remission phase of the 1(st), 2(nd), and 3(rd) are not statistically significant, and the occurrence rate of the left or right side and of the gender, male or female, are also statistically insignificant. However, it is possible to infer that a patient might face a pain attack phase when his or her remission phase has lapsed for about three years. This prediction may be applied when developing treatment plans for patients with glossopharyngeal neuralgia.

Implications and mechanism of action of gabapentin in neuropathic pain

Gabapentin is an anti-epileptic agent but now it is also recommended as first line agent in neuropathic pain, particularly in diabetic neuropathy and post herpetic neuralgia. α2δ-1, an auxillary subunit of voltage gated calcium channels, has been documented as its main target and its specific binding to this subunit is described to produce different actions responsible for pain attenuation. The binding to α2δ-1 subunits inhibits nerve injury-induced trafficking of α1 pore forming units of calcium channels (particularly N-type) from cytoplasm to plasma membrane (membrane trafficking) of pre-synaptic terminals of dorsal root ganglion (DRG) neurons and dorsal horn neurons. Furthermore, the axoplasmic transport of α2δ-1 subunits from DRG to dorsal horns neurons in the form of anterograde trafficking is also inhibited in response to gabapentin administration. Gabapentin has also been shown to induce modulate other targets including transient receptor potential channels, NMDA receptors, protein kinase C and inflammatory cytokines. It may also act on supra-spinal region to stimulate noradrenaline mediated descending inhibition, which contributes to its anti-hypersensitivity action in neuropathic pain.

Motor cortex stimulation for facial chronic neuropathic pain: A review of the literature

Background:

Facial chronic neuropathic pain (FCNP) is a disabling clinical entity, its incidence is increasing within the chronic pain population. There is indication for neuromodulation when conservative treatment fails. Motor cortex stimulation (MCS) has emerged as an alternative in the advanced management of these patients. The aim of this work is to review the worldwide literature on MCS for FCNP.

Methods:

A PubMed search from 1990 to 2012 was conducted using established MeSH words. A total of 126 relevant articles on MCS focused on chronic pain were selected and analysed. Series of cases were divided in (1) series focused on MCS for FCNP, and (2) MCS series of FCNP mixed with other chronic pain entities.

Results:

A total of 118 patients have been trialed for MCS for FCNP, 100 (84.7%) pursued permanent implantation of the system, and 84% of them had good pain control at the end of the study. Male: female ratio was about 1:2 in the whole group of studies; mean age was 58 years (range, 28–83), and mean pain duration was 7 years (range, 0.6–25). Four randomized controlled studies have been reported, all of them not focused on MCS for FCNP. The most common complication was seizure followed by wound infection. Preoperative evaluation, surgical techniques, and final settings varied among the series.

Conclusion:

MCS for FNCP is a safe and efficacious treatment option when previous managements have failed; however, there is still lack of strong evidence (larger randomized controlled multicentre studies) that MCS can be offered in a regular basis to FNCP patients.

Identifying the trigeminal nerve branches for transovale radiofrequency thermolesion: "no pain, no stress"

BACKGROUND

Radiofrequency thermorhizotomy of the trigeminal nerve is a known treatment of trigeminal neuralgia. Analysis of verbal responses to electric stimulation of the trigeminal rootlets has been the only method available to localize the affected branch, but patient discomfort may lead to unreliable verbal responses, resulting in increased morbidity or even therapeutic failure. Orthodromically elicited evoked potentials of the trigeminal nerve have also been used, but their application is tedious and results may vary.

OBJECTIVE

To develop an electrophysiological method for intraoperative localization of the trigeminal nerve branches.

METHODS

A series of 55 patients under general anesthesia during radiofrequency thermorhizotomy were studied. The trigeminal nerve root was stimulated through the foramen ovale with the RF electrode. Antidromic responses were recorded from the 3 divisions of the trigeminal nerve in the face. Effectiveness rate, pain relief, recurrence, complications, and patient comfort after the procedure were analyzed.

RESULTS

Reproducible and easily obtained antidromic responses were clearly recorded in every subdivision of the trigeminal nerve in all patients. Ninety-four percent of patients experienced immediate pain relief after the procedure. The recurrence rate was 12.72%, and the surgical morbidity was 20%.

CONCLUSION

This method proved to be useful to determine the exact localization of individual subdivisions of the trigeminal nerve in anesthetized patients, making this procedure safer and more comfortable for them.

Pharmacological versus microvascular decompression approaches for the treatment of trigeminal neuralgia: clinical outcomes and direct costs

In idiopathic trigeminal neuralgia (TN) the neuroimaging evaluation is usually normal, but in some cases a vascular compression of trigeminal nerve root is present. Although the latter condition may be referred to surgery, drug therapy is usually the first approach to control pain. This study compared the clinical outcome and direct costs of (1) a traditional treatment (carbamazepine [CBZ] in monotherapy [CBZ protocol]), (2) the association of gabapentin (GBP) and analgesic block of trigger-points with ropivacaine (ROP) (GBP+ROP protocol), and (3) a common TN surgery, microvascular decompression of the trigeminal nerve (MVD protocol). Sixty-two TN patients were randomly treated during 4 weeks (CBZ [n = 23] and GBP+ROP [n = 17] protocols) from cases of idiopathic TN, or selected for MVD surgery (n = 22) due to intractable pain. Direct medical cost estimates were determined by the price of drugs in 2008 and the hospital costs. Pain was evaluated using the Numerical Rating Scale (NRS) and number of pain crises; the Hospital Anxiety and Depression Scale, Sickness Impact Profile, and satisfaction with treatment and hospital team were evaluated. Assessments were performed at day 0 and 6 months after the beginning of treatment. All protocols showed a clinical improvement of pain control at month 6. The GBP+ROP protocol was the least expensive treatment, whereas surgery was the most expensive. With time, however, GBP+ROP tended to be the most and MVD the least expensive. No sequelae resulted in any patient after drug therapies, while after MDV surgery several patients showed important side effects. Data reinforce that, (1) TN patients should be carefully evaluated before choosing therapy for pain control, (2) different pharmacological approaches are available to initiate pain control at low costs, and (3) criteria for surgical interventions should be clearly defined due to important side effects, with the initial higher costs being strongly reduced with time.

Treatment of trigeminal neuralgia: role of radiofrequency ablation

Trigeminal neuralgia (TN) is a neuropathic pain condition affecting the face. It has a significant impact on the quality of life and physical function of patients. Evidence suggests that the likely etiology is vascular compression of the trigeminal nerve leading to focal demyelination and aberrant neural discharge. Secondary causes such as multiple sclerosis or brain tumors can also produce symptomatic TN. Treatment must be individualized to each patient. Carbamazepine remains the drug of choice in the first-line treatment of TN. Minimally invasive interventional pain therapies and surgery are possible options when drug therapy fails. Younger patients may benefit from microvascular decompression. Elderly patients with poor surgical risk may be more suitable for percutaneous trigeminal nerve rhizolysis. The technique of radiofrequency rhizolysis of the trigeminal nerve is described in detail in this review.

Effectiveness of the association between carbamazepine and peripheral analgesic block with ropivacaine for the treatment of trigeminal neuralgia

Treatment of trigeminal neuralgia (TN) is achieved by using adjuvant analgesics like antiepileptics, with carbamazepine (CBZ) being the first-line approach for TN patients, although side effects may be present. Other approaches using gabapentin, namely when associated with peripheral analgesic block of TN trigger points with the local anesthetic ropivacaine (ROP), resulted in decreased pain and daily drug intake (reduced side effects). This study evaluates if the association between CBZ and the peripheral block with ROP reinforces the clinical value of CBZ. In this parallel, double-blinded study, idiopathic TN patients were randomized to receive during 4 weeks either CBZ (CBZ; n = 21) or CBZ associated with the peripheral analgesic block using ROP (CBZ + ROP; n = 24). The primary outcome measures were the following: i) pain intensity, evaluated by the numerical rating scale; ii) number of pain crises; and iii) number needed to treat. Evaluation points were at the beginning (day 1) and end (day 29) of treatment and after a follow-up of 5 months (month 6). Both protocols resulted in a decrease of pain intensity and number of pain crises, but only the association CBZ + ROP showed i) a significant stronger reduction in pain intensity at month 6 and ii) a significant decrease in the daily dose of CBZ given to patients (both at day 29 and month 6). In contrast, the daily dose in CBZ-only patients remained constant or even increased. The number needed to treat for the association CBZ + ROP over the CBZ protocol reduced from 5 at the end of the 4-week treatment to 3 after the 5-month follow-up. Data reinforce the use of CBZ as a primary tool to control pain in TN patients, as the association CBZ + ROP i) improves the clinical qualities of CBZ, ii) strongly reduces the daily dose of CBZ, and iii) reduces the potential side effects attributed to high doses of CBZ.

Factors That Influence Outcome of Percutaneous Balloon Compression in the Treatment of Trigeminal Neuralgia

BACKGROUND:

Percutaneous balloon compression is an effective, low-cost, simple therapeutic modality with the special advantage of being the only percutaneous technique that can be simply performed with the patient under general anesthesia for the treatment of trigeminal neuralgia.

OBJECTIVE:

To identify surgical and individual parameters that could influence outcome in patients with trigeminal neuralgia treated with percutaneous balloon compression.

METHODS:

Within a 5-year period, 66 consecutive percutaneous balloon compressions were performed in 47 patients. The medical and surgical records of all patients were retrospectively reviewed and analyzed for a possible correlation between the following parameters and outcome: balloon shape, balloon volume, compression time, age, sex, type of pain, duration of disease, previous procedures, and trigeminal division affected. Univariate and multivariate analyses were used to test for statistical significance.

RESULTS:

The initial success rate was 85%, and 36% of the responders are still pain free with a mean follow-up of approximately 20 months, whereas in 33 patients, trigeminal pain recurred after a mean of approximately 17 months. Of the investigated parameters, significant correlations were obtained between balloon shape and all aspects of outcome, previous operations and complication rate, pain type and complication rate, and compression time and postoperative numbness.

CONCLUSION:

The balloon shape is a parameter with a very strong impact on outcome, and balloon volume should be adjusted to this parameter. Persistent elliptical balloon shapes should raise consideration of aborting the procedure. There were no differences in outcomes between 60 seconds and longer compression times. The number of previous operations did not correlate with pain relief, but seemed to increase the risk of complications. Patients with multiple sclerosis seemed to obtain similar benefit from the procedure as do patients with classic trigeminal neuralgia.

Cardiovascular response during trigeminal ganglion compression for trigeminal neuralgia according to the use of local anesthetics

OBJECTIVES

There are controversies about the use of local anesthetics during balloon compression for trigeminal neuralgia (TN) as a protective factor for cardiovascular events. The objective of this study was to investigate cardiovascular parameters (blood pressure and heart rate [HR]) of patients that underwent trigeminal balloon compression with local anesthetics compared to a control group (placebo).

METHODS

This is a randomized controlled study; 55 patients were randomized into two groups: study (deep sedation and trigeminal block with 0.8-mL lidocaine 2%) and control group (deep sedation and trigeminal injection of 0.8-mL saline). Blood pressure and HR were measured in five distinct moments: preoperative, during puncture for local anesthesia/placebo, during puncture with the catheter, during balloon compression, and final evaluation. Statistical analysis was performed with Pearson's chi (2) and McNemar tests and the analysis of variance for repetitive measures.

RESULTS

The means of systolic and diastolic blood pressures (SBP and DBP, respectively) were higher in the control group when compared to the study group at the evaluation during puncture with the catheter (p < 0.001) and balloon compression (p < 0.001 and p = 0.018 for DBP and SBP, respectively). There was an increase in the HR in the control group during the procedure (p = 0.017).

CONCLUSION

The use of local anesthetics during the trigeminal balloon compression for TN can have a preventive role for the risk of cardiovascular events.

Injection of botulinum toxin type A (BOTOX) into trigger zone of trigeminal neuralgia as a means to control pain

This article illustrates a case of persistent trigeminal neuralgia in a medically compromised 65-year-old female who did not respond to pharmacotherapy. She had undergone several peripheral neurectomies as well as a failed right posterior fossa exploration that resulted in a cerebrospinal fluid leak. Persistent pain over the right external nasal area and right mental region was relieved for several hours after daily injections of bupivacaine. A trial of a single dose of 100 units of botulinum toxin type A (BOTOX) diluted in 2.5 mL saline was injected into the external nasal trigger zone (60 units) and to the mental nerve region (40 units). She achieved complete pain relief in the external nasal region for 5 months. Pain recurred and the site was again injected with 100 units of botulinum toxin type A (BOTOX). Pain relief at the mental region was partial. This was finally controlled with peripheral neurectomy. The patient was pain free with a maintenance dose of 200 mg carbamazepine daily for about 1 year, after which she elected to undergo stereotactic gamma knife radiosurgery when pain recurred at the external nasal region.

Trigeminal injury causes kappa opioid-dependent allodynic, glial and immune cell responses in mice

BACKGROUND

The dynorphin-kappa opioid receptor (KOR) system regulates glial proliferation after sciatic nerve injury. Here, we investigated its role in cell proliferation following partial ligation of infraorbital nerve (pIONL), a model for trigeminal neuropathic pain. Mechanical allodynia was enhanced in KOR gene deleted mice (KOR-/-) compared to wild type mice. Using bromodeoxyuridine (BrdU) as a mitotic marker, we assessed cell proliferation in three different areas of the trigeminal afferent pathway: trigeminal nucleus principalis (Vp), trigeminal root entry zone (TREZ), and trigeminal ganglion (TG).

RESULTS

In KOR-/- mice or norBNI-treated mice, the number of proliferating cells in the Vp was significantly less than in WT mice, whereas cell proliferation was enhanced in TREZ and TG. The majority of the proliferating cells were nestin positive stem cells or CD11b positive microglia in the Vp and macrophages in the TG. GFAP-positive astrocytes made a clear borderline between the CNS and the PNS in TREZ, and phosphorylated KOR staining (KOR-p) was detectable only in the astrocytes in CNS in WT mice but not in KOR-/- or norBNI-treated mice.

CONCLUSIONS

These results show that kappa opioid receptor system has different effects after pIONL in CNS and PNS: KOR activation promotes CNS astrocytosis and microglial or stem cell proliferation but inhibits macrophage proliferation in PNS. The trigeminal central root has a key role in the etiology and treatment of trigeminal neuralgia, and these newly identified responses may provide new targets for developing pain therapies.

Conditional gene deletion reveals functional redundancy of GABAB receptors in peripheral nociceptors in vivo

BACKGROUND

gamma-aminobutyric acid (GABA) is an important inhibitory neurotransmitter which mainly mediates its effects on neurons via ionotropic (GABA(A)) and metabotropic (GABA(B)) receptors. GABA(B) receptors are widely expressed in the central and the peripheral nervous system. Although there is evidence for a key function of GABA(B) receptors in the modulation of pain, the relative contribution of peripherally- versus centrally-expressed GABA(B) receptors is unclear.

RESULTS

In order to elucidate the functional relevance of GABA(B) receptors expressed in peripheral nociceptive neurons in pain modulation we generated and analyzed conditional mouse mutants lacking functional GABA(B1) subunit specifically in nociceptors, preserving expression in the spinal cord and brain (SNS-GABA(B1)-/- mice). Lack of the GABA(B1) subunit precludes the assembly of functional GABA(B) receptor. We analyzed SNS-GABA(B1)-/- mice and their control littermates in several models of acute and neuropathic pain. Electrophysiological studies on peripheral afferents revealed higher firing frequencies in SNS-GABA(B1)-/- mice compared to corresponding control littermates. However no differences were seen in basal nociceptive sensitivity between these groups. The development of neuropathic and chronic inflammatory pain was similar across the two genotypes. The duration of nocifensive responses evoked by intraplantar formalin injection was prolonged in the SNS-GABAB(1)-/- animals as compared to their control littermates. Pharmacological experiments revealed that systemic baclofen-induced inhibition of formalin-induced nociceptive behaviors was not dependent upon GABA(B1) expression in nociceptors.

CONCLUSION

This study addressed contribution of GABA(B) receptors expressed on primary afferent nociceptive fibers to the modulation of pain. We observed that neither the development of acute and chronic pain nor the analgesic effects of a systematically-delivered GABA(B) agonist was significantly changed upon a specific deletion of GABA(B) receptors from peripheral nociceptive neurons in vivo. This lets us conclude that GABA(B) receptors in the peripheral nervous system play a less important role than those in the central nervous system in the regulation of pain.

Trigeminal neuralgia in a patient with spontaneous intracranial hypotension

Spontaneous intracranial hypotension and trigeminal neuralgia are examples of pain syndromes arising from shifting anatomical relationships in the posterior fossa. We report both conditions occurring in the same patient and resolving following surgical closure of a cervical nerve root sleeve dural defect. This case further elucidates the pathophysiologic basis of both forms of head pain.

Persistent trigeminal artery causing "double" neurovascular conflict

We report the case of a 73-year-old woman who presented with right VI nerve palsy and homolateral atypical trigeminal neuralgia; standard neuroradiological investigation of orbital/retroorbital regions and intracranial arteries excluded the most commonly demonstrable underlying causes while brain magnetic resonance (T1-weighted fat suppression; T2-weighted thin-section) and magnetic resonance angiography disclosed the evidence of "double" neurovascular conflict because of persistent trigeminal artery with aneurysmal dilation. A role of this almost rare vascular condition in causing painful ophthalmoplegia is discussed.

Carbamazepine Transbuccal Delivery: The Histo-Morphological Features of Reconstituted Human Oral Epithelium and Buccal Porcine Mucosae in the Transmucosal Permeation

Transbuccal drug delivery is an attractive way of administration since several well-known advantages are provided, especially with respect to peroral management. Carbamazepine (CBZ) is an anticonvulsant which is useful in controlling neuropathic pain, and it is currently administered by peroral route, although its absorption and bioavailability is limited due to various factors. The oral cavity could be an interesting site for transbuccal CBZ delivery due to two properties: slow administration of constant low drug doses and less dose-related side effects. However, in transbuccal absorption a major limitation could be the low permeability of the mucosa which results in low drug bioavailability; thus the aptitude of the drug to penetrate the buccal mucosa has to be assessed by using tissue models resembling human normal mucosa. In our experience, CBZ well permeates mucosal membranes. In order to assess the efficacy of CBZ transbuccal delivery and to verify the reliability of these tissues in permeability testing before and after the passage of CBZ, the histo-morphological features of reconstituted human oral (RHO) epithelium (E) and buccal porcine mucosae were investigated. Significant histological changes due to CBZ passage were observed both in RHO-E and porcine mucosa. The main findings detected in RHO samples were cellular swellings with a signet ring-like appearance, nuclear swelling, prominent nucleoli lined against the nuclear membrane and the presence of keratohyalin granules. The most striking finding regarding porcine buccal mucosa was a cytoplasmic vacuolization, mainly involving the basal layer.