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.

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.

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

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.

Motor Cortex Stimulation for Facial Pain.

Motor cortex stimulation (MCS) has been used in the treatment of intractable neuropathic facial pain for nearly 30 years. While efficacy rates have been noted as high as 88% in some studies, considerable variability in treatment response remains. Additionally, MCS is often cited as providing diminishing relief over time, and there are few long-term studies on efficacy. Complications are generally mild and include infection, hardware complication, seizure, and transient neurological deficit. Despite relatively minimal use, MCS remains a viable treatment option for the appropriately selected facial pain patients that have proved refractory to conservative management.

High-Frequency Peripheral Nerve Stimulation for Craniofacial Pain.

Since the first successful use of high-frequency electrical stimulation of trigeminal branches for treatment of facial pain in 1962, neuromodulation techniques become well established but remain greatly underutilised. Most subsequent implantation techniques and commercial devices for peripheral nerve stimulation, available until the last decade, utilised frequencies in the range 1-100 Hz. With the commercial introduction of 10-kHz spinal cord stimulation, there has been renewed interest in peripheral applications of kHz frequency neuromodulation. High-frequency biphasic stimulation causes rapid onset, reversible conduction block in mammalian nerves which might be useful in human peripheral neuromodulation applications, but the conduction block induced at kilohertz frequencies may not be the only mechanism contributing to analgesia. We discuss likely mechanisms of action of high-frequency peripheral nerve stimulation and present several clinical examples of successful use of this modality in various facial pain conditions. A change to sub-threshold higher frequencies in the 10 kHz range adds a number of distinct advantages. The lack of paresthesias is welcomed by patients. The ability to place the stimulating electrode approximately 1 cm away from the targeted nerve has an anatomical and surgical advantage.

Deep Brain Stimulation for Facial Pain.

Electro-modulation of subcortical deep brain structures by surgically implanted electrodes is now standard evidence-based treatment for movement disorders such as Parkinson's disease and essential tremor and is approved for dystonia and obsessive-compulsive disorder under a humanitarian exemption. Historically, deep brain stimulation (DBS) for multiple indications has demonstrated acceptable complication rates, rare mortality, and reducing morbidity as the technology and the techniques of its application have advanced. DBS for the amelioration of pain has been performed since the early 1950s, and became widely used in the 1970s, when targeting the somatosensory thalamus was shown to be efficacious for intractable pain syndromes including facial pain. The technique fell out of favour in the late 1990s after 2 multicentre trials failed to meet end-point criteria. Since these trials, DBS for pain has remained for investigational or "off-label" use. Criticisms from previous literature have involved unsuitability of patient selection, as well as inconsistencies in neurosurgical technique. Clinical success with DBS for facial pain has been for the treatment of a variety of chronic neuropathic and nociceptive pain syndromes; including trigeminal neuropathy, post-herpetic neuralgia, deafferentation facial pain, "atypical" facial pain, cluster headaches and other trigeminal autonomic cephalalgias, as well as head and neck pathologies, most often which have been resistant to all other 1st- and 2nd-line medical and surgical treatments, when DBS has become a "last treatment option." An enhanced understanding of the mechanisms of action of DBS for pain will enhance outcome, and appropriately prescribe evolving novel nuclear brain targets.

Cervical Spinal Cord Stimulation for Facial Pain.

Neuropathic facial pain can be exceedingly difficult to manage with conventional therapies. Since this pain may be excruciating and often debilitating and some patients do not respond or do not tolerate conventional treatments, the interest in neuromodulation therapies is increasing. One of the most commonly used neuromodulation therapies, spinal cord stimulation, has recently shown promise in treating facial pain. We reviewed the current literature to determine usefulness of spinal cord stimulation in management of refractory facial pain. Our review indicates that for some patients with intractable pain in portions of the face, cervical spinal cord stimulation may be effective at reducing pain.

Peripheral Nerve Stimulation for Facial Pain Using Conventional Devices: Technique and Complication Avoidance.

The introduction of peripheral neuromodulation to treat headache and facial pain two decades ago opened up the field to non-neurosurgical practitioners, given the relatively low risk and technical ease of the procedure. These procedures, primarily occipital nerve stimulation (ONS) and trigeminal branch stimulation such as supra- and infraorbital nerve stimulation, are now established to be effective in a number of facial pain and headache syndromes, despite their lack of approval by regulatory agencies such as the US Food and Drug Administration (FDA). For that reason and others, dedicated hardware for these procedures has not yet been developed, thus relying on hardware designed for placement in the epidural space for spinal cord stimulation (SCS). This has led to a series of technical issues and device-related complications not traditionally seen with SCS. I will review the surgical technique of ONS and peripheral nerve stimulation of the head and face utilizing this equipment, and discuss methods learned by experienced practitioners over the years to minimize device-related complications.

Classification of Facial Pain: A Clinician's Perspective.

Successful management of facial pain starts with making correct diagnosis. Diagnostic errors, particularly early on in evaluation of facial pain patients are not uncommon, and some of this may be related to the lack of uniform classification that would satisfy needs of different specialists. Here, we critically review several most common classification schemes and try to compare and contrast their strength and unique features. We also attempt to link multiple terminologies describing same clinical conditions and provide a rationale for developing a unified nosological approach. Based on our findings, we conclude that despite many previous attempts, much work needs to be done to create a universally accepted, comprehensive but at the same time simple and user-friendly, facial pain classification, with the ultimate goal of integrating such classification into a treatment-guiding algorithm(s).

Peripheral Nerve Stimulation for Facial Pain Using Wireless Devices.

Since its original introduction several decades ago, peripheral nerve stimulation (PNS) of the craniofacial region has been traditionally performed using devices intended for spinal cord stimulation applications with inevitably high rate of technical challenges and procedural complications. The lower invasiveness of recently developed wireless neurostimulation systems makes them much better suited for craniofacial applications. Here, we discuss the preliminary clinical data from several published reports and the ongoing multicenter prospective study of wireless PNS in the craniofacial region. Advances in wireless transmission of electrical signals may make wireless neurostimulation even more attractive in the future. Since most of the evidence supporting PNS for facial pain comes from small subsets of the population, case series and case reports, there will need to be larger, randomized controlled trials with cost efficacy analyses in order to validate the role of wireless PNS as the standard of care.

Transcutaneous Electrical Nerve Stimulation for Facial Pain.

Transcutaneous electrical nerve stimulation (TENS) has been used for its analgesic effects for chronic pain, including facial pain. Here, we summarize how the electrical stimulation of branches of the trigeminal nerve via TENS has been utilized to reduce pain resulting from trigeminal neuralgia, temporomandibular joint disorder, migraine and other headache types, and ocular pain sensations. TENS has been used for both short-term (one session) and long-term (multiple sessions) pain control with little to no adverse effects reported by subjects. The results of the summarized studies suggest TENS is an effective non-invasive, non-pharmacologic means of pain control for patients with facial pain conditions.

Transcranial Direct Current Stimulation in the Treatment of Facial Pain.

Non-invasive neuromodulation techniques such as transcranial direct current stimulation (tDCS) enable researchers and health care professionals to gain unique insight into brain functions and to treat a number of neurological and psychiatric conditions. Repeated applications of anodal tDCS over the primary motor cortex (M1) have been shown to produce long-lasting relief of neuropathic pain. tDCS is a technique that can induce and modulate brain plasticity and thus be suitable for treating diverse chronic pain conditions, disorders associated with substantial reorganization of central nervous system activity. The number of published basic research and clinical papers in this field is increasing exponentially, but the number of studies that include patients with facial pain is still limited, and there are no "gold standards" with regard to how to treat the various kinds of pain disorders. Pharmacoresistant facial pain is a substantial burden for the patient as manifested by its interference with daily functioning and reduced health status associated with pain severity. Without doubt, further trials are needed to optimize stimulation parameters and find effective protocols for this disorder. In addition, evaluation of the clinical effects of tDCS shows that low-intensity electrical stimulation techniques are exceptionally suitable for gaining further insight into the functional role of a given brain region, e.g. how brain processes emerge and can be altered in anatomically distributed, but functionally connected, brain networks.

Percutaneous Electrical Nerve Stimulation for Facial Pain.

Percutaneous electrical nerve stimulation (PENS) is a novel, minimally invasive and useful treatment modality. Its use in complex facial pain has been on the rise, and its utility will further increase with the advances in the technology and renewed interest in the field of peripheral neuromodulation. PENS therapy can be used both as diagnostic and therapeutic option. The precise mechanism of action is not known, although a combination of electrical neuromodulation and release of endogenous morphine-like substance in the central nervous system appears as plausible explanation. We analyse the various studies in the literature and discuss the Southampton data regarding facial pain treatment with PENS therapy. We believe that PENS therapy for facial pain and headache is currently underutilised. It is safe, economical and should certainly be part of the armamentarium in the treatment of complex facial pain and headache.

Peripheral Nerve Stimulation for Facial Pain Using Conventional Devices: Indications and Results.

Trigeminal branch stimulation is a type of peripheral nerve stimulation (PNS) used to treat a variety of craniofacial pain disorders. Common indications include trigeminal neuralgia, trigeminal neuropathic pain, trigeminal deafferentation pain, trigeminal postherpetic neuralgia, supraorbital neuralgia, and migraine headaches. Supraorbital and infraorbital arrays are the most common electrode configurations, although preauricular, mandibular branch, and subcutaneous peripheral nerve field stimulation arrays have also been described. Trigeminal branch stimulation may be used as a stand-alone neuromodulation therapy or it may be combined with occipital nerve, sphenopalatine ganglion, or Gasserian ganglion stimulation to treat more complex pain patterns. Consistent with other forms of PNS, trigeminal branch stimulation is a minimally invasive, safe, and straightforward method of treating medically refractory neuropathic pain.

Gasserian Ganglion Stimulation for Facial Pain.

Non-neuralgic trigeminal neuropathic pain can be challenging in terms of treatment as pharmacological interventions often tend to be ineffective. Within the pain-transmitting pathway, the Gasserian ganglion (GG) is a rather unique anatomical and physiological structure where the sensory (including pain) information from the entire half of the face undergoes primary processing in a very compact and clearly defined entity. Moreover, GG is positioned in a completely immobile intradural location (the Meckel's cave) and is insulated from the brain by a layer of dura. As a confluence of all three trigeminal branches, GG allows one to achieve clinical effect on the entire half of the face with a relatively small surgical intervention while maintaining an ability to select exact facial regions based on known somatotopic organization of nerve fibers. Therefore, when it comes to electrical neuromodulation, the GG stimulation (GGS) may be a unique solution for treatment of medically refractory facial pain. GGS was introduced in 1970s and continues to be a recognized surgical modality with multiple published clinical series describing multi-year experience in hundreds of facial pain patients. GGS is particularly useful in treatment of patients with chronic trigeminal neuropathic pain and persistent idiopathic facial pain who tried and failed or were not considered good candidates for the conventional surgical interventions. With advances in lead technology, intraoperative visualization and stereotactic navigation, percutaneous GGS became a minimally invasive surgical intervention that is recommended for consideration in complex facial pain. Here, we review the clinical data and summarize the current state of GGS in facial pain treatment.

Facial presentations of migraine, TACs, and other paroxysmal facial pain syndromes.

OBJECTIVE: To assess the prevalence of facial pain (V2 and/or V3) presentations among nearly 3,000 patients with headache treated in a university tertiary care center. METHODS: Between 2010 and 2018, we routinely assessed the prevalence of facial pain presentations of all patients with primary headaches. RESULTS: Of 2,912 patient datasets, 291 patients reported facial pain either as an independent or as an additional symptom. Among patients with migraine, 2.3% (44 of 1,935) reported a facial involvement, most commonly in V2. Of these, 18 patients (40.9%) experienced the pain predominantly in the face. In patients with cluster headache, 14.8% (42 of 283) reported a facial involvement, of which 31.0% perceived the pain predominantly in the face. A facial involvement was seen in 45.0% of patients with paroxysmal hemicrania (9 of 20), 21.4% of patients with hemicrania continua (9 of 42), and 20.0% of patients with short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing/short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (3 of 15). In addition, we present 6 patients who reported a constant side-locked facial pain with superseded well-defined facial pain attacks of 10- to 30-minute duration that appeared several times per day. CONCLUSION: Our data suggest that a facial involvement in primary headaches is infrequent but not uncommon. A sole facial presentation of primary headache symptomatology seems to be exceptionally rare. We describe 3 different types of facial pain involvement and, in this context, distinguish patients with paroxysmal orofacial pain syndromes that have not been previously described. These patients may represent a new entity that could tentatively be called constant unilateral facial pain with added attacks.

Burst or Conventional Peripheral Nerve Field Stimulation for Treatment of Neuropathic Facial Pain.

BACKGROUND: Trigeminal Neuropathic Pain (TNP) is a chronic facial pain syndrome caused by a lesion or disease affecting one or more branches of the trigeminal nerve. It may, for example, result from accidental injury to a branch of the trigeminal nerve by trauma or during surgery; it may also be idiopathic. TNP is typically constant, in contrast to most cases of the commoner trigeminal neuralgia. In some cases, pain may be refractory to pharmacological treatment. Peripheral nerve field stimulation is recognized as an effective minimally invasive surgical treatment option for this debilitating condition. To date, stimulation has used conventional tonic waveforms, which generate paraesthesia in the stimulated area. This is the first report of the use of paraesthesia-free burst pattern stimulation for TNP. METHODS: Seven patients were treated at the John Radcliffe Hospital for TNP from 2016 to 2018. Mean duration of preoperative symptoms was five years. All patients had exhausted pharmacological measures to limited effect. The initial three patients had tonic stimulation with the subsequent four having burst stimulation. Outcome was assessed using the numeric pain rating scale preoperatively and postoperatively at three and six months and one year. Side-effects and complications were also assessed as well as reduction in analgesic medication use. RESULTS: All patients achieved pain reduction of at least 50% at 6 months (range 50-100%, mean 81%, p = 0.0082). Those in the burst stimulation group were paraesthesia free. One patient developed a postoperative infection for which the system had to be removed and is awaiting reimplantation. There were no other complications in either group. CONCLUSION: Burst stimulation conferred similar pain control to tonic stimulation in our small cohort, and there were similar reductions in pain medication use. An additional benefit of burst stimulation is freedom from paraesthesia. Larger scale studies are needed to further evaluate burst stimulation and compare its efficacy with that of tonic stimulation.