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

Reappraising the psychosomatic approach in the study of "chronic orofacial pain": looking for the essential nature of these intractable conditions

As burning mouth syndrome (BMS) and atypical odontalgia (AO) continue to remain complex in terms of pathophysiology and lack explicit treatment protocol, clinicians are left searching for appropriate solutions. Oversimplification solves nothing about what bothers us in clinical situations with BMS or AO. It is important to treat a complicated phenomenon as complex. We should keep careful observations and fact-finding based on a pragmatic approach toward drug selection and prescription with regular follow-up. We also need to assess the long-term prognosis of treatment with a meticulous selection of sample size and characteristics. Further investigation of BMS and AO from a psychosomatic perspective has the potential to provide new insight into the interface between brain function and "chronic orofacial pain."

Outcomes and Predictors of Response of Duloxetine for the Treatment of Persistent Idiopathic Dentoalveolar Pain: A Retrospective Multicenter Observational Study

Background

Duloxetine has been reported to significantly relieve the pain of persistent idiopathic dentoalveolar pain (PIDP); however, the number of studies available is scarce and no study has identified the predictors of response of duloxetine for the treatment of PIDP.

Objective

To report the efficacy, safety, and identification of positive predictors of duloxetine for PIDP patients through a retrospective multicenter observational study.

Methods

We retrospectively reviewed the clinical database of PIDP patients who were prescribed duloxetine at 3 hospitals between January 2018 and November 2021. Demographic and pain-related baseline data, efficacy of patients after 3 months of medication by visual analog scale (VAS) scores for pain and adverse events were extracted and analyzed. The predictors of pain-relieving effect of duloxetine were identified by logistic regression analysis.

Results

A total of 135 patients were included in this study. Side effects occurred immediately after taking duloxetine in 24 (17.8%) patients, and the treatment with duloxetine was discontinued on 13 of them because they could not tolerate the side effects. Other 11 (8.1%) patients gradually tolerated the side effects within 2 weeks. Ninety-four out of 122 (77.0%) patients obtained pain relief with VAS significantly decreased (p < 0.01) and the other 28 (23.0%) patients stopped taking the drug because of weak efficacy. Binary logistic regression analysis showed that short disease duration (OR = 1.017, 95% CI = 1.004–1.030, P = 0.012) was an independent predictor of the positive response of duloxetine.

Conclusion

This study confirmed that duloxetine can significantly improve chronic pain of PIDP patients, and the safety was tolerable. Patients with shorter disease duration had more benefit from duloxetine.

Limitations

This is a retrospective observational study. Long-term efficacy and safety of duloxetine in the treatment of PIDP patients were not evaluated.

Clinical Characteristics of Predominantly Unilateral Oral Cenesthopathy With and Without Neurovascular Contact

Oral cenesthopathy (OC) is characterized by unusual oral discomfort without corresponding evidence, and it has often been categorized as "delusional disorder, somatic type". Regarding possible causative factors of OC, involvement of neurovascular contact (NVC) of the trigeminal nerve, which transmits not only pain but also thermal, tactile, and pressure sensations, has never been observed yet. This study aimed to investigate the relationship between clinical characteristics of unilateral OC and the presence of trigeminal nerve NVC. This is a retrospective comparative study that involved 48 patients having predominantly unilateral OC who visited the Psychosomatic Dentistry Clinic of Tokyo Medical and Dental University between April 2016 and February 2019. Magnetic resonance imaging was performed to assess NVC presence. The Oral Dysesthesia Rating Scale (Oral DRS) was used to assess the various oral sensations and functional impairments besides psychometric questionnaires. Clinical characteristics were retrospectively obtained from the patients' medical charts. NVC was present in 45.8% (22/48) of the patients. There was no significant difference in sex, age, psychiatric history, oral psychosomatic comorbidity, and psychometric questionnaire scores between patients with and without NVC. However, compared to the patients with NVC, the patients without NVC had significantly higher scores for overall subjective severity of OC symptoms (p = 0.008). Moreover, patients having predominantly unilateral OC without NVC showed significantly higher scores in symptom severity and functional impairment of the following parameters: movement (p = 0.030), work (p = 0.004), and social activities (p = 0.010). In addition, compared with the patients with NVC, the patients without NVC showed significantly higher averages of the total symptom severity scale (SSS) and functional impairment scale (FIS) scores in the Oral DRS (p = 0.015 and p = 0.031, respectively). Furthermore, compared with the patients with NVC, the patients without NVC had significantly higher numbers of corresponding symptoms in both the SSS and FIS (p = 0.041 and p = 0.007, respectively). While NVC may be involved in the indescribable subtle OC symptoms, more complex mechanisms may also exist in OC patients without NVC, which yield varying and more unbearable oral symptoms.

Potential Molecular Targets for Treating Neuropathic Orofacial Pain Based on Current Findings in Animal Models

This review highlights potential molecular targets for treating neuropathic orofacial pain based on current findings in animal models. Preclinical research is currently elucidating the pathophysiology of the disease and identifying the molecular targets for better therapies using animal models that mimic this category of orofacial pain, especially post-traumatic trigeminal neuropathic pain (PTNP) and primary trigeminal neuralgia (PTN). Animal models of PTNP and PTN simulate their etiologies, that is, trauma to the trigeminal nerve branch and compression of the trigeminal root entry zone, respectively. Investigations in these animal models have suggested that biological processes, including inflammation, enhanced neuropeptide-mediated pain signal transmission, axonal ectopic discharges, and enhancement of interactions between neurons and glial cells in the trigeminal pathway, are underlying orofacial pain phenotypes. The molecules associated with biological processes, whose expressions are substantially altered following trigeminal nerve damage or compression of the trigeminal nerve root, are potentially involved in the generation and/or exacerbation of neuropathic orofacial pain and can be potential molecular targets for the discovery of better therapies. Application of therapeutic candidates, which act on the molecular targets and modulate biological processes, attenuates pain-associated behaviors in animal models. Such therapeutic candidates including calcitonin gene-related peptide receptor antagonists that have a reasonable mechanism for ameliorating neuropathic orofacial pain and meet the requirements for safe administration to humans seem worth to be evaluated in clinical trials. Such prospective translation of the efficacy of therapeutic candidates from animal models to human patients would help develop better therapies for neuropathic orofacial pain.

Radiographic Interpretation in Oral Medicine and Hospital Dental Practice

Oral medicine practice includes the diagnosis and nonsurgical treatment of oral and orofacial diseases and oral manifestations of systemic conditions. Oral medicine specialists in medical and dental settings often require imaging in assessment and treatment of these conditions. This article reviews imaging that may be used in practice, particularly as relevant for facial pain, bone conditions, and salivary gland disease. It reviews imaging that may be considered in a hospital setting for assessment of admitted patients, patient evaluation before surgical procedures, and provision of dentistry in a hospital setting for patients who cannot submit to treatment in an outpatient setting.

Invasive and Non-Invasive Electrical Neuromodulation in Trigeminal Nerve Neuralgia: A Systematic Review and Meta-Analysis

BACKGROUND

Trigeminal neuralgia is a chronic disease characterized by intense facial pain that is caused by trigeminal nerve affectation. It usually affects adults from 50 years of age, and is more frequent in women. Additionally, it presents serious psychological effects that often lead to depression, which is why it is considered highly disabling. The therapeutic approach is based on the modification of nerve activity through electrical, surgical or chemical stimulation in specific regions of the nervous system.

OBJECTIVE

To perform a meta-analysis of the scientific literature related to invasive and non-invasive electrical neuromodulation of trigeminal neuralgia, in order to assess their effects over pain and adverse effects.

METHODS

A literature search was conducted in 4 databases, followed by a manual search of articles on invasive or non-invasive electrical neuromodulation to control the pain of trigeminal neuralgia, including the last 15 years.

RESULTS

Regarding non-invasive methods, clinical trials did not present enough results in order to perform a meta-analysis. Regarding invasive methods, clinical trials meta-analysis showed no statistical differences between different treatment methods. In all cases, improvements in patients' pain were reported, although results regarding adverse effects were variable.

CONCLUSION

In the treatment of trigeminal neuralgia, the continuous radiofrequency provides better short and medium-term results, but pulsed radiofrequency shows less adverse effects after treatment, and has better results in the long-term.

Dexmedetomidine Combined With Butorphanol or Sufentanil for the Prevention of Post-operative Nausea and Vomiting in Patients Undergoing Microvascular Decompression: A Randomized Controlled Trial

Background: Patients undergoing microvascular decompression are often accompanied with high risk of post-operative nausea and vomiting (PONV). In this study, we compare the antiemetic efficacy of butorphanol or sufentanil combined with dexmedetomidine in patients undergoing microvascular decompression.

Methods: Patients undergoing microvascular decompression were randomized into two groups. The primary outcome was the occurrence and severity of PONV during the 72 h after surgery. Secondary outcomes included levels of pain intensity and sedation and consumption of opioids at 1, 2, 6, 12, 24, 48, and 72 h after surgery. We also recorded the intraoperative hemodynamics, consumption of narcotic drugs, operation and anesthesia time, estimated blood loss, infusion volume and urine output, requirements of rescue antiemetics or analgesics, the satisfaction scores of patients and surgeons, complications, and length of stay.

Results: The overall incidence rates of nausea and vomiting during the 72 h after surgery were significantly reduced in group DB (76.00 and 44.00% in group DS vs. 54.17% and 22.92% in group DB, P < 0.05). Patients in group DB had a lower incidence of nausea than those in group DS at intervals of 1–6 and 6–24 h (P < 0.05). However, patients in group DB had a lower incidence of vomiting than those in group DS only at intervals of 1–6 h (P < 0.05). Similarly, the number of patients requiring rescue antiemetics was also significantly reduced in group DB compared with that in group DS at intervals of 1–6 h (P < 0.05). The number of patients experiencing moderate to severe PONV was comparable between the two groups during 72 h after surgery (P > 0.05). The consumption of opioid morphine equivalent was significantly reduced in group DB (P < 0.05). Compared with those in group DS, the satisfaction scores of both patients and surgeons were significantly increased in group DB (P < 0.05).

Conclusion: Butorphanol combined with dexmedetomidine could reduce early PONV and the number of patients requiring rescue antiemetics, especially at intervals of 1–6 h, while the satisfaction scores of both patients and surgeons were significantly increased.

Chronic Facial Pain: Trigeminal Neuralgia, Persistent Idiopathic Facial Pain, and Myofascial Pain Syndrome-An Evidence-Based Narrative Review and Etiological Hypothesis

Trigeminal neuralgia (TN), the most common form of severe facial pain, may be confused with an ill-defined persistent idiopathic facial pain (PIFP). Facial pain is reviewed and a detailed discussion of TN and PIFP is presented. A possible cause for PIFP is proposed. (1) Methods: Databases were searched for articles related to facial pain, TN, and PIFP. Relevant articles were selected, and all systematic reviews and meta-analyses were included. (2) Discussion: The lifetime prevalence for TN is approximately 0.3% and for PIFP approximately 0.03%. TN is 15-20 times more common in persons with multiple sclerosis. Most cases of TN are caused by neurovascular compression, but a significant number are secondary to inflammation, tumor or trauma. The cause of PIFP remains unknown. Well-established TN treatment protocols include pharmacotherapy, neurotoxin denervation, peripheral nerve ablation, focused radiation, and microvascular decompression, with high rates of relief and varying degrees of adverse outcomes. No such protocols exist for PIFP. (3) Conclusion: PIFP may be confused with TN, but treatment possibilities differ greatly. Head and neck muscle myofascial pain syndrome is suggested as a possible cause of PIFP, a consideration that could open new approaches to treatment.