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.

Differences in the Clinical Characteristics of Persistent Idiopathic Facial Pain (Atypical Odontalgia) Patients with or Without Neurovascular Compression of the Trigeminal Nerve.

BACKGROUND: Persistent idiopathic facial pain (PIFP) is the unexplained pain along the territory of the trigeminal nerve, including nonorganic tooth pain called atypical odontalgia (AO). Though PIFP is debilitating to patients' livelihood and well-being, its pathophysiology remains poorly understood. Although neurovascular compression (NVC) of the trigeminal nerve is known to be associated with trigeminal neuralgia (TN), the relationship between NVC and other orofacial pains has not been fully elucidated. METHODS: In this study, we investigated the differences in the characteristics of PIFP (primarily AO) patients in the presence or absence of NVC. A retrospective analysis was performed on data from 121 consecutive patients who had been diagnosed with unilateral PIFP according to the criteria of the International Classification of Headache Disorders (ICHD)-3 and underwent magnetic resonance imaging scans of the head. RESULTS: In the group without NVC, characteristic findings were significant for psychiatric morbidity, somatization, and pain disability, when compared with the group with NVC. Furthermore, the group without NVC exhibited significant headache, noncardiac chest pain, shortness of breath, and pain catastrophizing. CONCLUSIONS: These results suggest that PIFP patients can be divided into two groups: one consistent with a neuropathic pain phenotype when NVC is present and a functional somatic symptom phenotype when presenting without NVC. Our findings may enable a more precise understanding of pathophysiology of PIFP and lead to better treatment strategies.

Predictive role of gnathological techniques for the treatment of persistent idiopathic facial pain (PIFP).

INTRODUCTION/BACKGROUND: Persistent idiopathic craniofacial pain (PIFP) is a heterogeneous group of pain syndromes whose main characteristic is the daily presence of persistent pain for at least 3 months. The pathophysiology of PIFP is still not entirely known and probably related to biological and psychological factors. Although PIFP has been attributed to the central neuron activity, the importance of masticatory muscles as a possible pathogenic mechanism was recently demonstrated. The main purpose of our paper was to identify the physiological rest position of the mandible with minimal tonus of both the elevator and depressor muscles and the neuromuscular trajectory of mouth closing obtained by transcutaneous electrical stimulation (TENS) and maintained with the use of an occlusal device, known as orthotic. MATERIALS AND METHODS: The VAS scale for facial pain and the migraine disability assessment score (MIDAS) index for patient quality of life were evaluated at the beginning of the study for the 38 subjects that came to our attention. Our research included two phases. The first phase consisted of kinesiographic and electromyographic (EMG) examinations of the masticatory muscles and a 45-min application of TENS in order to deprogram the muscular activity. Kinesio-electromyographic examinations were repeated in the second phase. The main evaluated parameter was jaw deflection or deviation on the sagittal and frontal planes before and after TENS during patient tooth occlusion. Patients that showed a significant modification of this parameter were treated with orthotics for 12 months. RESULTS: The results of a 12-month follow-up show a sharp reduction of the VAS (pre-orthotic 9.05, range 8-10, SD 0.8; post-orthotic 5.87, range 1-5, SD 0.7) and an improvement in the quality of life (MIDAS). CONCLUSIONS: Our study demonstrated the usefulness of TENS as a screening method for the application of orthotics. This non-invasive and/or non-painful procedure could be a useful complementary treatment in this patient population. The results of the study also confirm the role of masticatory muscle dynamics as a possible pathogenic mechanism in patients with PIFP.

The role of electrophysiological investigations of masticatory muscles in patients with persistent idiopathic facial pain.

INTRODUCTION: The authors tried to establish whether there is any electrophysiological difference of masticatory muscle activity between patients with persistent idiopathic facial pain (PIFP) and healthy subjects. METHODS: Twenty-eight PIFP patients (6 men and 22 women, mean age 40 years) and 28 normal subjects (12 men and 16 women, mean age 40 years) underwent EMG of temporal and masseter muscles before and after transcutaneous electric nerve stimulation (TENS). RESULTS: After TENS stimulation, the mean amplitude difference was found to be smaller than the baseline before TENS in the PIFP patients compared with healthy subjects. CONCLUSIONS: The peculiar behavior of masticatory muscles after TENS could be relevant in order to explain the well-known improvement of pain reported by some PIFP patients after orthosis positioning.

Usefulness of an occlusal device in the treatment of medication overuse headache and persistent idiopathic facial pain: preliminary results.

There is a debate in literature about the therapeutic usefulness of oral devices in patients suffering from Medication Overuse Headache (MOH) or in patients suffering from Persistent Idiopathic Facial Pain (PIFP). From the case histories of 3356 patients, referred to us with a diagnosis of chronic craniofacial pain for assessment of the eventual application of an occlusal device to correct an impaired neuromuscular relationship between the mandible and the maxilla, we selected, following the criteria of the International Classification of Headache Disorders (ICHD-3beta), two groups of patients suffering from MOH and PIFP. All patients of the two groups underwent a Kinesiographic exam and an EMG to evaluate the freeway space (FWS). Patients presenting an impaired FWS were placed in treatment with the application of an occlusal device. At the follow-up after 6 months and after 1 year, we found a significant decrease in pain with regard to the intensity resulting in the reduction of clinical disability. The preliminary data collected using the VAS scale and the MIDAS questionnaire confirm that the neuromuscular cranio-mandibular system can have an important role in the diagnostic process of the MOH and the PIFP, suggesting the usefulness of treatment with an occlusal device, where there is adequate FWS.

Atypical Facial Pain: a Comprehensive, Evidence-Based Review.

PURPOSE OF REVIEW: The purpose of this article is to focus on an excruciating disorder of the face, named atypical facial pain or persistent idiopathic facial pain (PIFP). It is considered an underdiagnosed condition with limited treatment options. Facial pain can be a debilitating disorder that affects patients' quality of life. Up to 26% of the general population has suffered from facial pain at some point in their lives. It is important to highlight the different types of facial pain to be able to properly manage this condition accordingly. RECENT FINDINGS: Newer interventional modalities such as pulsed radiofrequency ablation (PFR) of the sphenopalatine ganglion, peripheral nerve field stimulators (PNFS), and botulinum toxin injections have promising results. In summary, more prospective studies such as randomized controlled trials are necessary to explore the possibility of their more widespread use as viable procedures for the treatment of PIFP. In this review article, we describe the workup and diagnosis of PIFP and highlight recent literature regarding the pathophysiology and treatment of PIFP. PIFP is an excruciating disorder of the face often misdiagnosed as trigeminal neuralgia (TN) However, unlike TN symptoms, the pain is persistent rather than intermittent, usually unilateral, and without autonomic signs or symptoms. When a clinician encounters a patient with neuropathic facial pain whose symptoms are incongruent with the more common etiologies, the diagnosis of atypical facial pain must be entertained. Treatment of PIFP is multidisciplinary. Unfortunately, few randomized controlled trials for the treatment of PIFP exist. However, there are a select number of pharmacological, non-pharmacological, and interventional treatment options that have proven to be moderately effective.

Effectiveness and Safety of Flupentixol and Melitracen Tablets for the Treatment of Patients with Persistent Idiopathic Facial Pain: A Retrospective Observational Study.

BACKGROUND: Flupentixol and melitracen are being investigated for their potential effectiveness in managing persistent idiopathic facial pain (PIFP), based on their mechanisms of action as dopamine receptor antagonists and noradrenaline/serotonin reuptake inhibitors, respectively. The efficacy and safety of flupentixol and melitracen (FM) tablets in treating PIFP were retrospectively analyzed at our hospital. OBJECTIVES: The aim of this study is to determine the effectiveness and safety of FM tablets in treating PIFP. STUDY DESIGN: Retrospective unicentric cohort design. SETTING: An academic university hospital. METHODS: A retrospective analysis was conducted on a cohort comprising 128 patients with a definite diagnoses of PIFP who were treated with FM tablets (flupentixol 0.5 mg and melitracen 10 mg tablet, >= 4 tablets/d) from January 2022 through May 2023 at an academic university hospital. Baseline conditions were statistically described, and Numeric Rating Scale (NRS-11) scores of pain levels before and during treatment were collected. Pain relief rates were calculated. Differences in baseline characteristics between responsive and unresponsive patients were evaluated using statistical tests. Additionally, the side effects experienced during treatment were summarized. RESULTS: Among the included 128 patients, 105 (82.0%) patients achieved pain relief (pain NRS-11 score reduction rate >= 50%). The median treatment onset time was 3 (1-7) days. NRS-11 scores of responsive patients at week 2, week 4, week 8, and week 12 were significantly lower than the baseline NRS-11 scores (P < 0.001), regardless of their Hamilton Depression Rating Scale score. Pain duration was the only factor that related to responsiveness (Wilcoxon rank sum test, P < 0.001; logistic regression, P = 0.001). No serious side effects that could affect patients' lives were observed during the first week of treatments. LIMITATIONS: Due to its retrospective nature, this study is limited by its lack of a randomized control. The lack of data on nonresponders who did not achieve significant pain relief hinders assessing overall change and the placebo effects'. Patients previously treated with antidepressants were excluded, making it hard to determine if FM tablets were a better treatment for PIFP. Additionally, the small sample size in a single center may be influenced by chance variation in pain relief. CONCLUSIONS: FM tablets showed its potential in the management of PIFP with considerable efficacy and safety. Early administration of FM tablets after a PIFP diagnosis may result in a high possibility of pain relief.

Post-traumatic Trigeminal Neuropathy Associated With Endodontic Therapy: A Systematic Review.

A painful or non-painful trigeminal nerve lesion brought on by trauma that exhibits symptoms and/or clinical evidence of trigeminal nerve dysfunction is known as painful post-traumatic trigeminal neuropathy (PTTN). In relation to this, the term post-traumatic persistent dentoalveolar pain (PDAP) is an idiopathic condition of chronic neuropathic origin that manifests as a diagnostic challenge for dental practitioners. Neuropathic pain is defined by the International Association for the Study of Pain (IASP) as "pain initiated or caused by a primary lesion or dysfunction in the nervous system." PDAP is located primarily in the teeth and jaws. This study systematically reviews how likely it is to get painful PTTN if the patient received endodontic therapy and the duration between doing root canal therapy (RCT) and getting PTTN. A systematic review was carried out using key search terms from PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials (CENTRAL) with English as the only permitted language. There were strict inclusion requirements. The 10 articles that were included showed a prevalence of an endodontic procedure anywhere from three to 48 months following post-endodontic treatment, and it mainly affects females in their mid-40s with no variation regarding the areas, whether it is in the maxilla or mandible. The lack of information about the association between RCT and PTTN led practitioners to make wrong diagnoses, which made the patient unwilling to seek further help. So, in this review, we identified some visible characteristics that can help in that process.

Atypical Facial Pain.

Atypical facial pain (AFP), or persistent idiopathic facial pain, is a chronic and diffuse distribution of facial pain along the territory of the trigeminal nerve. This condition occurs in the absence of any neurologic deficit or any other obvious etiology. AFP is one of the most challenging conditions to diagnose due to lack of clear diagnostic criteria. Diagnosis of this condition is made by exclusion of other known etiologies. Specific disease modalities cannot be targeted, resulting in a deficiency of clear treatment protocol. Despite the limitations of evidence-based literature, tricyclic antidepressants have proved effective and are considered the treatment choice for AFP.