Acute facial neuralgia related to initiation of emtricitabine/tenofovir for HIV PrEP: a report of two cases in a PrEP demonstration trial.

BACKGROUND: Emtricitabine (FTC) and tenofovir disoproxil fumarate (TDF) fixed-dose combination (FTC/TDF) is generally well-tolerated, although treatment-related adverse events have been reported. METHODS: We report two cases of persons using FTC/TDF PrEP who had acute neuralgia in a Chinese PrEP demonstration trial. RESULTS: Neurological symptoms subsided upon treatment discontinuation. Symptoms were reported as similar to one case's previous experiences with dolutegravir (DTG)+FTC+tenofovir alafenamide (TAF) (for PEP), leading to permanent discontinuation of PrEP. CONCLUSION: Acute facial neuralgia appears to be a rare idiosyncratic adverse event to FTC/TDF.

Review of craniofacial pain syndromes involving the greater occipital nerve: relevant anatomy, clinical findings, and interventional management.

Craniofacial pain syndromes exhibit a high prevalence in the general population, with a subset of patients developing chronic pain that significantly impacts their quality of life and results in substantial disabilities. Anatomical and functional assessments of the greater occipital nerve (GON) have unveiled its implication in numerous craniofacial pain syndromes, notably through the trigeminal-cervical convergence complex. The pathophysiological involvement of the greater occipital nerve in craniofacial pain syndromes, coupled with its accessibility, designates it as the primary target for various interventional procedures in managing craniofacial pain syndromes. This educational review aims to describe multiple craniofacial pain syndromes, elucidate the role of GON in their pathophysiology, detail the relevant anatomy of the greater occipital nerve (including specific intervention sites), highlight the role of imaging in diagnosing craniofacial pain syndromes, and discuss various interventional procedures such as nerve infiltration, ablation, neuromodulation techniques, and surgeries. Imaging is essential in managing these patients, whether for diagnostic or therapeutic purposes. The utilization of image guidance has demonstrated an enhancement in reproducibility, as well as technical and clinical outcomes of interventional procedures. Studies have shown that interventional management of craniofacial pain is effective in treating occipital neuralgia, cervicogenic headaches, cluster headaches, trigeminal neuralgia, and chronic migraines, with a reported efficacy of 60-90% over a duration of 1-9 months. Repeated infiltrations, neuromodulation, or ablation may prove effective in selected cases. Therefore, reassessment of treatment response and efficacy during follow-up is imperative to guide further management and explore alternative treatment options. Optimal utilization of imaging, interventional techniques, and a multidisciplinary team, including radiologists, will ensure maximum benefit for these patients.

Efficacy of ultrasound-guided infiltration with levobupivacaine and triamcinolone for myofascial pain syndrome of the quadratus lumborum: a retrospective observational study

Abstract Introduction and objectives: Myofascial Pain Syndrome (MPS) of the Quadratus Lumborum muscle (QL) is a frequent cause of chronic low back pain. With this study, we aimed to assess the efficacy of ultrasound-guided infiltration with 0.25% levobupivacaine and 40 mg triamcinolone for MPS of the QL. Methods: Observational and retrospective study of participants submitted to ultrasound-guided infiltration of the QL muscle from January 1, 2015 to June 31, 2019. Pain intensity was assessed using the five-point pain Numeric Rating Scale (NRS): pre-intervention, at 72 hours, 1 month, 3 months and 6 months post-intervention. Additional data collected were demographic characteristics, opioid consumption, and adverse effects. Results: We assessed 90 participants with mean age of 55.2 years. Sixty-eight percent of participants were female. Compared to the pre-intervention assessment, there was an improvement in pain at 72 hours (Mean Difference [MD = 3.085]; 95% CI: 2.200-3.970, p < 0.05), at the 1st month (MD = 2.644; 95% CI: 1.667-3.621, p < 0.05), at the 3rdmonth (MD = 2.017; 95% CI: 0.202-2.729, p < 0.05) and at the 6th month (MD = 1.339; 95% CI 0.378-2.300, p < 0.05), post-intervention. No statistically significant differences in opioid consumption were observed. No adverse effects associated with the technique were reported. Conclusions: Ultrasound-guided infiltration of the QL muscle is a safe and effective procedure for the treatment of pain in the QL MPS within 6 months post-intervention.

Orofacial Migraine and Other Idiopathic Non-Dental Facial Pain Syndromes: A Clinical Survey of a Social Orofacial Patient Group.

Background: Orofacial pain syndromes (OFPs) are a heterogeneous group of syndromes mainly characterized by painful attacks localized in facial and oral structures. According to the International Classification of Orofacial Pain (ICOP), the last three groups (non-dental facial pain, NDFP) are cranial neuralgias, facial pain syndromes resembling primary headache syndromes, and idiopathic orofacial pain. These are often clinical challenges because the symptoms may be similar or common among different disorders. The diagnostic efforts often induce a complex diagnostic algorithm and lead to several imaging studies or specialized tests, which are not always necessary. The aim of this study was to describe the encountered difficulties by these patients during the diagnostic-therapeutic course. Methods: This study was based on the responses to a survey questionnaire, administered to an Italian Facebook Orofacial Patient Group, searching for pain characteristics and diagnostic-therapeutic care courses. The questionnaire was filled out by patients affected by orofacial pain, who were 18 years and older, using a free online tool available on tablets, smartphones, and computers. Results: The sample was composed of 320 subjects (244F/76M), subdivided by age range (18-35 ys: 17.2%; 36-55 ys: 55.0%; >55 ys 27.8%). Most of the patients were affected by OFP for more than 3 years The sample presented one OFP diagnosis in 60% of cases, more than one in 36.2% of cases, and 3.8% not classified. Trigeminal neuralgia is more represented, followed by cluster headaches and migraines. About 70% had no pain remission, showing persisting background pain (VAS median = 7); autonomic cranial signs during a pain attack ranged between 45 and 65%. About 70% of the subjects consulted at least two different specialists. Almost all received drug treatment, about 25% received four to nine drug treatments, 40% remained unsatisfied, and almost 50% received no pharmacological treatment, together with drug therapy. Conclusion: To the authors' knowledge, this is the first study on an OFP population not selected by a third-level specialized center. The authors believe this represents a realistic perspective of what orofacial pain subjects suffer during their diagnostic-therapeutic course and the medical approach often results in unsatisfactory outcomes.

Orofacial pain for clinicians: A review of constant and attack-like facial pain syndromes.

BACKGROUND: Primary headache syndromes such as migraine are among the most common neurological syndromes. Chronic facial pain syndromes of non-odontogenic cause are less well known to neurologists despite being highly disabling. Given the pain localization, these patients often consult dentists first who may conduct unnecessary dental interventions even if a dental cause is not identified. Once it becomes clear that dental modalities have no effect on the pain, patients may be referred to another dentist or orofacial pain specialist, and later to a neurologist. Unfortunately, neurologists are also often not familiar with chronic orofacial pain syndromes although they share the neural system, i.e., trigeminal nerve and central processing areas for headache disorders. CONCLUSION: In essence, three broad groups of orofacial pain patients are important for clinicians: (i) Attack-like orofacial pain conditions, which encompass neuralgias of the cranial nerves and less well-known facial variants of primary headache syndromes; (ii) persistent orofacial pain disorders, including neuropathic pain and persistent idiopathic facial/dentoalveolar pain; and (iii) other differential diagnostically relevant orofacial pain conditions encountered by clinicians such as painful temporomandibular disorders, bruxism, sinus pain, dental pain, and others which may interfere (trigger) and overlap with headache. It is rewarding to know and recognize the clinical picture of these facial pain syndromes, given that, just like for headache, an internationally accepted classification system has been published and many of these syndromes can be treated with medications generally used by neurologists for other pain syndromes.

Outcome of Surgical Treatments of Chronic Pain Caused by Trigeminal Neuropathy.

BACKGROUND: Trigeminal neuropathy represents a subset of several facial pain syndromes that are difficult to diagnose and treat. Although many surgical modalities are available, outcomes remain suboptimal. The aim of this study is to present our experience in management of trigeminal neuropathy with a focus on the effectiveness and long-term efficacy of the different surgical procedures. METHODS: A single-center retrospective cohort study was conducted from December 2012 until February 2020. RESULTS: Twenty-eight patients (19 females, 9 males) were included in this study. They had 40 surgical interventions. At last follow-up, 1 patient (33.3%) treated by spinal cord stimulation (SCS) had no pain recurrence and 2 patients (66.6%) had their devices removed because of therapeutic failure. Median time to pain recurrence after SCS was 19.5 months (interquartile range [IQR], 29.79 months). Six patients were treated with peripheral nerve stimulation (PNS). At last follow-up, 2 patients had satisfactory pain relief, whereas half of the patients had no improvement. For the 17 patients treated with computed tomography-guided trigeminal tractotomy/nucleotomy, true failure occurred 7 times in 6 patients. Median time to pain recurrence was 5.6 months (IQR, 6.2). Of the 6 patients treated with caudalis DREZ, 3 (50%) had satisfactory pain relief for >1 year and the median time to pain recurrence was 3.9 months (IQR, 29.53). CONCLUSIONS: Trigeminal neuropathy is a difficult to treat entity of facial pain syndromes. The long-term efficacy of available interventions does not meet patients' satisfaction. More organized prospective studies with longer follow-up are needed to define the patient population best served by each surgical modality.

Neuralgia and Atypical Facial, Ear, and Head Pain.

Though there have been considerable strides in the diagnosis and care of orofacial pain disorders, facial neuralgias, and myofascial pain dysfunction syndrome remain incredibly cumbersome for patients and difficult to manage for providers. Cranial neuralgias, myofascial pain syndromes, temporomandibular dysfunction (TMD), dental pain, tumors, neurovascular pain, and psychiatric diseases can all present with similar symptoms. As a result, a patient's quest for the treatment of their orofacial pain often begins on the wrong foot, with a misdiagnosis or unnecessary procedure, which makes it all the more frustrating for them. Understanding the natural history, clinical presentation, and management of facial neuralgias and myofascial pain dysfunction syndrome can help clinicians better recognize and treat these conditions. In this article, we review updated knowledge on the pathophysiology, incidence, clinical features, diagnostic criteria, and medical management of TN, GPN, GN, and MPDS.

Characteristics and natural disease history of persistent idiopathic facial pain, trigeminal neuralgia, and neuropathic facial pain.

OBJECTIVE: This study aimed to characterize key features, and to assess the clinical development of common nondental facial pain syndromes such as persistent idiopathic facial pain (PIFP), trigeminal neuralgia (TN), and neuropathic facial pain (NEUROP). METHODS: This is a longitudinal study in which prospective questionnaire data of patients presenting to a specialized outpatient clinic were collected from 2009 to 2019. A telephone interview was conducted with the same patients in 2020 to assess the natural disease history. RESULTS: n = 411 data sets of patients with chronic facial pain were compiled. Among these were n = 150 patients with PIFP, n = 111 patients with TN, and n = 86 patients with NEUROP. Guideline therapy had not been initiated in 38.7% (58/150; PIFP), 19.8% (22/111; TN), and 33.7% (29/86; NEUROP) patients. Of the patients with PIFP, 99.3% (149/150) had primarily consulted a dentist due to their pain syndrome. The additional telephone interview was completed by 236 out of the 411 patients (57.4%). Dental interventions in healthy teeth had been performed with the intention to treat the pain in many patients (78/94 [83.0%] PIFP; 34/62 [54.8%] TN; 19/43 [44.2%] NEUROP), including dental extractions. 11.3% (7/43) of the patients with TN had never profited from any therapy. In contrast, 29.8% (28/94) of the patients with PIFP had never profited from any therapy. Furthermore, the primary pharmaceutical therapy options suggested by national guidelines were, depending on the substance class, only considered to be effective by 13.8% (13/94; antidepressants) and 14.9% (14/94; anticonvulsants) of the patients with PIFP. CONCLUSIONS: Facial pain syndromes pose a considerable disease burden. Although treatment of TN seems to be effective in most patients, patients with PIFP and NEUROP report poor effectiveness even when following guideline therapy suggestions. In addition, unwarranted dental interventions are common in facial pain syndromes.

Radiofrequency Ablation for Craniofacial Pain Syndromes.

Headache disorders and trigeminal neuralgia are common conditions representing the types of craniofacial pain syndrome that can significantly impact quality of life. Many cases are refractory to traditional pharmacologic treatments, whether oral or intravenous. Radiofrequency ablation has been increasingly used as a tool to treat resistant, chronic pain of both of these disorders. Multiple studies have been reported that illustrate the efficacy of radiofrequency ablation in the treatment of the numerous headache subtypes and trigeminal neuralgia.

Idiopathic Facial Pain Syndromes­An Overview and Clinical Implications.

BACKGROUND: Idiopathic facial pain syndromes are relatively rare. A uniform classification system for facial pain became available only recently, and many physicians and dentists are still unfamiliar with these conditions. As a result, patients frequently do not receive appropriate treatment. METHODS: This article is based on pertinent publications retrieved by a selective search in PubMed, focusing on current international guidelines and the International Classification of Orofacial Pain (ICOP). RESULTS: The ICOP subdivides orofacial pain syndromes into six major groups, the first three of which consist of diseases of the teeth, the periodontium, and the temporomandibular joint. The remaining three groups (non-dental facial pain) are discussed in the present review. Attack-like facial pain syndromes most closely resemble the well-known primary headache syndromes, such as migraine, but with pain located below the orbitomeatal line. These syndromes are treated in accordance with the guidelines for the corresponding types of headache. Persistent idiopathic facial pain (PIFP) is a chronic pain disorder with persistent, undulating pain in the face and/or teeth, without any structural correlate. Since this type of pain tends to become chronified after invasive procedures, no dental procedures should be performed to treat it if the teeth are healthy; rather, the treatmentis similar to that of neuropathic pain, e.g., with antidepressant and anticonvulsive drugs. Neuropathic facial pain is also undulating and persistent. It is often described as a burning sensation, and neuralgiform attacks may additionally be present. Trigeminal neuralgia is a distinct condition involving short-lasting, lancinating pain of high intensity with a maximum duration of two minutes. The first line of treatment is with medications; invasive treatment options should be considered only if pharmacotherapy is ineffective or poorly tolerated. CONCLUSION: With the aid of this pragmatic classification system, the clinician can distinguish persistent and attack-like primary facial pain syndromes rather easily and treat each syndrome appropriately.

Facial pain beyond trigeminal neuralgia.

PURPOSE OF REVIEW: Trigeminal neuralgia is a well-known facial pain syndrome with several treatment options. In contrast, non-neuralgiform idiopathic facial pain syndromes are relatively rare, reflected by the fact that, until 2020, no internationally accepted diagnostic classification existed. Like trigeminal neuralgia, these non-dental facial pain syndromes need to be managed by neurologists and pain specialists, but the lack of pathophysiological understanding has resulted in an underrepresented and undertreated patient group. RECENT FINDINGS: This work provides a brief overview of the most common primary facial pain syndromes, namely, the facial attack-like facial pain, which corresponds to attack-like headache, the persistent idiopathic facial pain (formerly 'atypical facial pain'), and trigeminal neuropathy. What these disorders have in common is that they should all be treated conservatively. SUMMARY: On the basis of pragmatic classifications, permanent and attack-like primary facial pain can be relatively easily differentiated from one another. The introduction of the new International Classification of Orofacial Pain offers the opportunity to better coordinate and concentrate scientific efforts, so that in the future the therapy strategies that are still inadequate, can be optimized.

A pain in the ear: Two case reports of nervus intermedius neuralgia and narrative review.

OBJECTIVE: Present two cases of nervus intermedius neuralgia (NIN) in which patients described unilateral deep ear pain as their primary complaint and present a summary of NIN cases reported in the literature. BACKGROUND: The nervus intermedius is a tiny branch of the facial nerve that, with neuralgia, can present as a deep ear pain (NIN). The International Classification of Headache Disorders, 3rd edition, (ICHD-3) criteria for an NIN diagnosis include a unilateral deep ear pain with possible radiation that occurs in paroxysms with sharp pain and a tactile trigger. METHODS: A PubMed search was conducted for NIN and geniculate neuralgia. Two patients recently diagnosed with NIN at a single clinic were selected for case reports to highlight the variability of symptom presentation. RESULTS: The two cases reported here and the 127 cases reported in the literature show a wider range of presentations than included in the ICHD-3 criteria, including variable pain radiation sometimes diagnosed as concurrent trigeminal, glossopharyngeal, or occipital neuralgia. Pain was reported as constant or paroxysmal, as well as dull, sharp, or neuralgiform with inconsistent presence of triggers. While ICHD-3 does mention reported taste change, lacrimation, and salivation, the literature reports a much wider range of potential features associated with NIN. Optimal medical treatment is unclear given the predominance of surgical reporting of positive response to microvascular decompression, nerve sectioning, or other procedures. The two cases described here were successfully managed medically. CONCLUSION: NIN can present as described in the ICHD-3, but a more variable presentation may be possible. More studies are needed to clarify presentation, optimal medical treatment, and surgical indications for patients with NIN, especially when patients have no clear neurovascular conflict on neuroimaging.

Neuromodulación en cefaleas y neuralgias craneofaciales: Guía de la Sociedad Española de Neurología y de la Sociedad Española de Neurocirugía / Neuromodulation in headache and craniofacial neuralgia: guidelines from the Spanish Society of Neurology and the Spanish Society of Neurosurgery

INTRODUCCIÓN: En los últimos años han surgido numerosos dispositivos de neuromodulación, invasivos y no invasivos, que se han aplicado en pacientes con cefaleas y neuralgias sin que exista una revisión actualizada de su eficacia y seguridad, ni recomendaciones de ninguna institución sanitaria sobre su uso específico en cada entidad nosológica. MÉTODOS: Neurólogos del Grupo de Cefaleas de la Sociedad Española de Neurología (SEN) y neurocirujanos expertos en neurocirugía funcional seleccionados por la Sociedad Española de Neurocirugía (SENEC), hemos realizado una revisión exhaustiva en el sistema Medline sobre neuromodulación en cefaleas y neuralgias. RESULTADOS: Presentamos una revisión actualizada y establecemos por primera vez unas recomendaciones consensuadas entre la SEN y la SENEC sobre el uso de la neuromodulación en cefaleas y neuralgias, adjudicando niveles de evidencia sobre su eficacia actual, específicamente en cada entidad nosológica. CONCLUSIONES: Los resultados actuales de los estudios proporcionan evidencias para la indicación de técnicas de neuromodulación en casos refractarios de cefaleas y neuralgias (sobre todo en migraña, cefalea en racimos y neuralgia del trigémino), seleccionados por neurólogos expertos en cefaleas, tras comprobar el agotamiento de las opciones farmacológicas. Adicionalmente, en el caso de la neuromodulación invasiva, se recomienda que los casos sean debatidos en comités multidisciplinarios y la cirugía sea realizada por equipos de neurocirujanos expertos en neurocirugía funcional y con una morbimortalidad aceptable

INTRODUCTION: Numerous invasive and non-invasive neuromodulation devices have been developed and applied to patients with headache and neuralgia in recent years. However, no updated review addresses their safety and efficacy, and no healthcare institution has issued specific recommendations on their use for these 2 conditions. METHODS: Neurologists from the Spanish Society of Neurology's (SEN) Headache Study Group and neurosurgeons specialising in functional neurosurgery, selected by the Spanish Society of Neurosurgery (SENEC), performed a comprehensive review of articles on the MEDLINE database addressing the use of the technique in patients with headache and neuralgia. RESULTS: We present an updated review and establish the first set of consensus recommendations of the SEN and SENC on the use of neuromodulation to treat headache and neuralgia, analysing the current levels of evidence on its effectiveness for each specific condition. CONCLUSIONS: Current evidence supports the indication of neuromodulation techniques for patients with refractory headache and neuralgia (especially migraine, cluster headache, and trigeminal neuralgia) selected by neurologists and headache specialists, after pharmacological treatment options are exhausted. Furthermore, we recommend that invasive neuromodulation be debated by multidisciplinary committees, and that the procedure be performed by teams of neurosurgeons specialising in functional neurosurgery, with acceptable rates of morbidity and mortality

Outcomes of Occipital Nerve Stimulation for Craniofacial Pain Syndromes.

OBJECTIVES: Occipital nerve regional stimulation (ONS) is reported to improve pain in several studies. We examined long-term pain and functional outcomes of ONS in an open-label prospective study. METHODS: Patients with medically refractory and disabling craniofacial pain were prospectively selected for ONS. Primary outcome was a change in mean daily pain intensity on the numeric pain rating scale (NPRS) at 6 months. Secondary outcomes included changes in NPRS, Headache Impact Test-6 (HIT-6), Migraine Disability Assessment (MIDAS), Pain Disability Index (PDI), Center for Epidemiologic Studies Depression Scale - Revised (CESD-R), and Short Form-36 version 2 (SF36) at last follow-up. RESULTS: Thirteen patients (mean age 49.7 ± 8.4) diagnosed with occipital neuralgia (6), hemicrania continua (2), persistent idiopathic facial pain (2), post-traumatic facial pain (1), cluster headache (1), and chronic migraine (1) were enrolled. Mean NPRS improved by 2.1 ± 2.1 at 6 months and 2.1 ± 1.9 at last follow-up (23.5 ± 18.1 months). HIT-6 decreased by 8.7 ± 8.8, MIDAS decreased by 61.3 ± 71.6, and PDI decreased by 17.9 ± 18. SF36 physical functioning, bodily pain, and social functioning improved by 16.4 ± 19.6, 18.0 ± 31.6, and 26.1 ± 37.3, respectively. Moderate to severe headache days (defined as ≥50% of baseline mean NPRS) were reduced by 8.9 ± 10.2 days per month with ONS. CONCLUSION: ONS reduced the long-term NPRS and moderate-severe monthly headache days by 30% and improved functional outcomes and quality of life. A prospective registry for ONS would be helpful in accumulating a larger cohort with longer follow-up in order to improve the use of ONS.

Photobiomodulation therapy to treat neuropathic oral pain after contagion by COVID-19 / Terapia de fotobiomodulação no tratamento de dor oral neuropática após contágio por COVID- 19

Objective: The purpose of this short communication is to show that although photobiomodulation in the treatment of neurophathic oral pain after COVID-19 contagion could be an option, photobiomodulation is not a new technique. PBMT was used with different protocols and pain was assessed using VAS (visual analogue scale - 0 until 10) before and after the consultation. Results: Evolution of VAS during the sessions showed a decrease in painful symptomatology as treatment was performed. Conclusion: Based on the results obtained in the present case report, we concluded that PBMT with the parameters used in this clinical case was an effective, noninvasive and a new option of treatment for neuralgia resulting from COVID-19. (AU)

Objetivo: O objetivo deste short communication é mostrar que, embora a fotobiomodulação no tratamento de dor oral neuropática após contágio por COVID-19 possa ser uma opção, a fotobiomodulação não é uma técnica recente. TFBM foi utilizado com diferentes protocolos e a dor foi avaliada por EVA (escala visual analógica - 0 a 10) antes e após a consulta. Resultados: A evolução da EAV durante as sessões mostrou uma diminuição da sintomatologia dolorosa à medida que o tratamento era realizado. Conclusão: Com base nos resultados obtidos no presente relato de caso, concluímos que a TFBM com os parâmetros utilizados neste caso clínico foi eficaz, não invasivo e uma nova opção de tratamento para a neuralgia decorrente do COVID-19 (AU)

Oxytocin-Dependent Regulation of TRPs Expression in Trigeminal Ganglion Neurons Attenuates Orofacial Neuropathic Pain Following Infraorbital Nerve Injury in Rats.

We evaluated the mechanisms underlying the oxytocin (OXT)-induced analgesic effect on orofacial neuropathic pain following infraorbital nerve injury (IONI). IONI was established through tight ligation of one-third of the infraorbital nerve thickness. Subsequently, the head withdrawal threshold for mechanical stimulation (MHWT) of the whisker pad skin was measured using a von Frey filament. Trigeminal ganglion (TG) neurons innervating the whisker pad skin were identified using a retrograde labeling technique. OXT receptor-immunoreactive (IR), transient receptor potential vanilloid 1 (TRPV1)-IR, and TRPV4-IR TG neurons innervating the whisker pad skin were examined on post-IONI day 5. The MHWT remarkably decreased from post-IONI day 1 onward. OXT application to the nerve-injured site attenuated the decrease in MHWT from day 5 onward. TRPV1 or TRPV4 antagonism significantly suppressed the decrement of MHWT following IONI. OXT receptors were expressed in the uninjured and Fluoro-Gold (FG)-labeled TG neurons. Furthermore, there was an increase in the number of FG-labeled TRPV1-IR and TRPV4-IR TG neurons, which was inhibited by administering OXT. This inhibition was suppressed by co-administration with an OXT receptor antagonist. These findings suggest that OXT application inhibits the increase in TRPV1-IR and TRPV4-IR TG neurons innervating the whisker pad skin, which attenuates post-IONI orofacial mechanical allodynia.

Transcranial Neurostimulation (rTMS, tDCS) in the Treatment of Chronic Orofacial Pain.

Although commonly seen in the clinical practice, chronic orofacial pain quite often does not have a clear unambiguous organic origin. It may be difficult to find optimal pharmacotherapy, and in many cases, this pain may become pharmacotherapy resistant. Neuromodulation, particularly with electromagnetic neurostimulation techniques, has been widely used for the treatment of different types of pharmacoresistant pain, and repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) exemplify readily available noninvasive neuromodulation methods. We have used rTMS and tDCS to treat pharmacoresistant chronic orofacial pain. rTMS uses an electromagnetic coil placed over the patient's head to induce electrical current impulses within the brain tissue, thereby modulating brain activity. In tDCS, an electrode placement location(s) must be chosen in accordance with the density and the time course of the current, mainly to prevent undesired pathological changes in the underlying tissue. Transcranial neuromodulation methods provide a nondestructive and reversible approach to treatment of severe and otherwise uncontrollable chronic orofacial pain. These methods may be curative - as a part of so called "reconstructive neurosurgery" stimulation of neural structures may be used as an alternative to surgical destruction of neural pathways.

Anatomy of Trigeminal Neuromodulation Targets: From Periphery to the Brain.

The trigeminal nerve complex is a very important and somewhat unique component of the nervous system. It is responsible for the sensory signals that arise from the most part of the face, mouth, nose, meninges, and facial muscles, and also for the motor commands carried to the masticatory muscles. These signals travel through a very complex set of structures: dermal receptors, trigeminal branches, Gasserian ganglion, central nuclei, and thalamus, finally reaching the cerebral cortex. Other neural structures participate, directly or indirectly, in the transmission and modulation of the signals, especially the nociceptive ones; these include vagus nerve, sphenopalatine ganglion, occipital nerves, cervical spinal cord, periaqueductal gray matter, hypothalamus, and motor cortex. But not all stimuli transmitted through the trigeminal system are perceivable. There is a constant selection and modulation of the signals, with either suppression or potentiation of the impulses. As a result, either normal sensory perceptions are elicited or erratic painful sensations are created. Electrical neuromodulation refers to adjustable manipulation of the central or peripheral pain pathways using electrical current for the purpose of reversible modification of the function of the nociceptive system through the use of implantable devices. Here, we discuss not only the distal components, the nerve itself, but also the sensory receptors and the main central connections of the brain, paying attention to the possible neuromodulation targets.

First Bite Syndrome Following Carotid Endarterectomy.

A 67-year-old man with a high position carotid plaque presented with severe pain in ipsilateral parotid region several days after carotid endarterectomy (CEA). The pain occurred at the first bite of each meal and resolved as further bite. We diagnosed the pain as first bite syndrome (FBS). FBS is infrequent but known as a complication associated with parapharyngeal space surgery. The pain is characterized by sharp pain in the parotid region associated with mastication. The cause is unclear but thought to the result from sympathetic denervation of the parotid gland, followed by parasympathetic nerve hypersensitivity. Only five cases associated with carotid endarterectomy (CEA) have been reported. We should be in mind that CEA for high position plaque is one of the risk factors to cause FBS associated with CEA. Neurologists and vascular surgeons as well as otolaryngologists should all be informed FBS as one of the complications after carotid endarterectomy.