Journal of Oral & Facial Pain and Headache, 02/2020

Aims: To test and re-examine the diagnostic criteria for neurovascular orofacial pain (NVOP) compared to posttraumatic trigeminal neuropathy (PTTN). Methods: Pain and patient characteristics were compared in patients with NVOP, PTTN, and NVOP initiated by trauma (PT-NVOP). NVOP criteria were based on prior studies, and PTTN was defined according to the International Classification of Headache Disorders, version 3 beta. Results: Of the 170 patients in the cohort, 90 had PTTN, 51 had NVOP, and 29 had PT-NVOP. None of the tested parameters in the NVOP and PT-NVOP patients were significantly different, and therefore these patients were combined into one group (T-NVOP). T-NVOP differed significantly from PTTN (P < .001) in periodic pain patterns, presence of autonomic and systemic signs, throbbing pain quality, and frequency of bilaterality. Pain quality in PTTN was more burning/stabbing than in NVOP (P = .003). Pain severity, waking from sleep, muscle sensitivity to palpation, and demographics were comparable. Conclusion: NVOP differs from PTTN in parameters essential to diagnosis: periodicity of pain, presence of autonomic and systemic accompanying signs, throbbing pain quality, and bilateral presentation. NVOP is amenable to abortive and prophylactic antimigraine therapies, distinguishing NVOP from PTTN in clinical features, treatment, and prognosis. Keywords: migraine, neurovascular orofacial pain, persistent idiopathic facial pain, post traumatic trigeminal neuropathy

Aims: To conduct a systematic review of the literature on the use of botulinum toxin for the treatment of cluster headache. Methods: A systematic review and data quality analysis were performed using PRISMA and GRADE guidelines, respectively. Inclusion and exclusion criteria were outlined prior to the search and aimed to select prospective studies that examined the use of botulinum toxin for the treatment of cluster headache. Results: Three studies resulted from the search that each included 10 to 17 subjects. All three demonstrated significant improvement in the frequency of headaches that occurred as quickly as 1 week following treatment. There was low-quality evidence that botulinum toxin was effective in reducing headache frequency and severity by at least 50%. Injections into the sphenopalatine ganglion may have a higher incidence of adverse events. Conclusion: This review summarizes the only prospectively collected efficacy and safety data regarding the use of botulinum toxin in cluster headache. Off-label use should be considered in certain cases. Further study is warranted to better characterize injection paradigms and patient selection, given the encouraging but limited data available. Keywords: botox, botulinum toxin, cluster headache

Aims: To examine the effectiveness and safety of using a CAD/CAM–derived injection guide for botulinum neurotoxin block of the sphenopalatine ganglion for trigeminal neuralgia treatment. Methods: Ten patients with second-division trigeminal neuralgia who did not respond to submucosal administration of botulinum neurotoxin were enrolled in this study. The target point around the sphenopalatine fossa was determined after fusion of computed tomography data with a scan of a maxillary model using a software program for dental implant surgery. A CAD/CAM–derived injection guide was fabricated. The guide was affixed to the patient's maxilla, and a needle was inserted to an exactly analyzed depth. Subsequently, 50 units of botulinum neurotoxin were injected. Pain intensity evaluated using a visual analog scale and pain frequency were measured. Results: By using the guides, sphenopalatine ganglion block with botulinum toxin was performed 18 times without any complications. The visual analog scale score (8.1 ± 1.0) and pain frequency (19.4 ± 8.8 times/day) decreased (to 1.9 ± 1.4 and 4.9 ± 5.4 times/day, respectively) significantly (P < .001). After 4 weeks, the mean subjective improvement achieved was 77.5% ± 13.8%, and all patients responded to treatment. Conclusion: Even without prior experience of sphenopalatine ganglion block, the CAD/CAM–derived guide enabled the accurate and safe administration of botulinum neurotoxin to the sphenopalatine ganglion for the treatment of trigeminal neuralgia. Keywords: botulinum neurotoxin therapy, computer-aided design/ computer-assisted manufacturing, sphenopalatine ganglion, surgical template, trigeminal neuralgia

Aims: To evaluate the effectiveness of manual therapy in the treatment of myofascial pain related to temporomandibular disorders. Methods: Randomized clinical trials were searched in the Cochrane Library, MEDLINE, Web of Science, Scopus, LILACS, and SciELO databases using the following keywords: temporomandibular joint disorders; craniomandibular disorders; myofascial pain syndromes; myofascial pain; exercise therapy; myofunctional therapy; physical therapy modalities; clinical trial; prospective studies; and longitudinal studies. Studies using the RDC/TMD and manual therapy for myofascial pain were included. All studies were evaluated using the Cochrane Risk of Bias tool. Results: Five studies were included in the present review. Of 279 total patients, 156 were treated with manual therapy only or manual therapy with counseling. Manual therapy was efficient for pain relief in all studies evaluated; however, manual therapy was not better than counseling or botulinum toxin. Conclusion: Manual therapy was better than no treatment in one study and better than counseling in another study; however, manual therapy combined with counseling was not statistically better than counseling alone, and manual therapy alone was not better than botulinum toxin. Manual therapy combined with home therapy was better than home therapy alone in one study. Further studies are required due to the inconclusive data and poor homogeneity found in this review. Keywords: exercise therapy, myofascial pain, myofascial pain syndromes, systematic review, temporomandibular joint disorders

Aims: To study the effect of platelet-rich plasma (PRP) injections on pain reduction in patients with temporomandibular joint osteoarthritis (TMJ OA). Methods: The authors performed a comprehensive search of the MEDLINE, PubMed, and Web of Science databases to retrieve RCTs published up to July 2018. Pain outcomes (visual analog scale scores) were extracted to assess the effect of PRP injections on TMJ OA. All data analyses were conducted using RevMan 5.3. Results: Six studies were included. According to the results of these trials, intra-articular injections of PRP were more effective than placebo for pain reduction (6 months postinjection: mean difference [MD] −2.82, 95% CI −3.39 to −2.25, P < .00001; 12 months postinjection: MD −3.29; 95% CI −4.07 to −2.52, P < .00001). Additionally, the comparison between PRP and hyaluronic acid injections showed a statistically significant difference in pain reduction in support of PRP (MD −0.81; 95% CI −1.22 to −0.40; P = .0001) at 12 months postinjection. All trials revealed a moderate risk of bias. Conclusion: Based on current evidence, PRP injections may reduce pain more effectively than placebo injections in TMJ OA at 6 months (level of evidence: moderate) and 12 months (level of evidence: moderate) postinjection. This significant difference in pain reduction could also be seen when PRP was compared to hyaluronic acid at 12 months postinjection (level of evidence: low). It can be cautiously interpreted that PRP has a beneficial effect on the relief of TMJ OA pain. Large-scale, low-bias RCTs are needed to test whether PRP injection should be a routine treatment for patients with TMJ OA. Keywords: meta-analysis, myofascial, pain, platelet-rich plasma, temporomandibular disorders

Aims: To identify the clinical characteristics of patients with primary and secondary burning mouth syndrome (BMS), to assess the effectiveness of pharmacotherapy in treating BMS, and to determine the clinical variables that may predict significant relief of clinical symptoms. Methods: A retrospective chart review of patients who underwent clinical management for BMS in the Massachusetts General Hospital between January 2011 and December 2016 was carried out. Information regarding demographics, diagnostics, and therapeutic characteristics was extracted and analyzed. Results: Of 112 BMS patients, 77 had primary BMS. Patients with primary and secondary BMS had similar clinical characteristics except when it came to the presence of at least one symptom of sensory discrepancy, which was more prevalent in primary BMS. Following pharmacologic intervention, 46.8% of the patients with primary BMS experienced significant relief in symptoms, and this therapy was associated with a lower level of pain, an onset of symptoms of less than 1 year, hyperlipidemia, absence of depression disorder, and nonconcurrent use of other neuropathic medications. In contrast, only 31.4% of patients with secondary BMS experienced significant relief in symptoms, and this was associated with the presence of anxiety disorder. Stepwise forward conditional logistic regression analysis suggested that nonconcurrent use of neuropathic medications was a predictor for significant relief of symptoms in patients with primary BMS. Likewise, the model suggested that presence of anxiety disorder was a predictor in patients with secondary BMS. Conclusion: The prevalence of an associated sensory discrepancy was higher in primary BMS. Pharmacologic intervention provided significant relief for approximately half of the patients with primary BMS and nearly one-third of the patients with secondary BMS. Concurrent use of neuropathic medications was a negative predictor, and presence of anxiety disorder a positive predictor, of therapeutic response among patients with primary BMS and secondary BMS, respectively. Keywords: burning mouth syndrome, facial pain, neuropathic pain, pain

Aims: To conduct a systematic review of the available evidence regarding the clinical characteristics and treatment of Ernest syndrome. Methods: A systematic search was carried out in the EBSCOhost, Embase, MEDLINE, ScienceDirect, Scopus, Web of Science, and Trip databases. The free terms "stylomandibular ligament" and "Ernest syndrome" were used, and the Boolean operator "OR" was used for connection of the terms. The research protocol was registered in PROSPERO (CRD42018112914). The results of this study are presented according to the PRISMA statement, and risk of bias was assessed according to the Quality Assessment Tool for Quantitative Studies of the Effective Public Health Practice Project. Results: A total of 57 articles were found, 5 of which met the selection criteria and were included in this review. The selected articles represent a population of 81 patients with primarily unilateral pain in the periauricular and mandibular areas. Diagnosis was established according to clinical history, recognition of pain on palpation of the mandibular angle, and remission following infiltration with local anesthesia. Concerning the treatments applied, infiltration with corticosteroids was highly successful, as was partial resection of the stylomandibular ligament and part of the styloid process. Furthermore, in refractory cases, the application of radiofrequency thermoneurolysis was described. Conclusion: The analyzed studies allow a better understanding of Ernest syndrome and the proposal of a tendinosis model for this condition. However, the evidence is scarce, and it is therefore necessary to carry out additional studies with better methodologic designs. Keywords: Ernest syndrome, inflammation, pain, stylomandibular ligament, temporomandibular disorders

Aims: To test for the possible antinociceptive effect of nifedipine in rodent models of acute and chronic neuropathic orofacial pain and the possible involvement of TRP- and NMDA-related processes in this effect. Methods: Acute nociceptive behavior was induced by administering formalin, cinnamaldehyde, glutamate, capsaicin, or acidified saline to the upper lip or hypertonic saline to the cornea of Swiss mice. Acute nociceptive behavior was also induced by formalin injected into the TMJ or mustard oil injected into the masseter muscle of Wistar rats. The chronic pain model involved infraorbital nerve transection (IONX) in Wistar rats to induce mechanical hypersensitivity, which was assessed with von Frey hair stimulation of the upper lip. The effects of pretreatment with nifedipine or vehicle (control) were tested on the nociceptive behaviors. Docking experiments were also performed. Statistical analysis included one-way ANOVA followed by Tukey post hoc test and two-way ANOVA followed by Bonferroni post hoc test (statistical significance P < .05). Results: Nifedipine produced significant antinociceptive effects in all of the acute nociceptive behaviors except that induced by capsaicin. The antinociceptive effects were attenuated by NMDA, TRPA1, or TRPM3 receptor antagonists. The IONX animals developed facial mechanical hypersensitivity, which was significantly reduced by nifedipine. The docking experiments suggested that nifedipine may interact with TRPM3 and NMDA receptors. Conclusion: The present study has provided novel findings in a variety of acute and chronic orofacial pain models showing that nifedipine, a selective inhibitor of L-type Ca2+ channels, can suppress orofacial nociceptive behavior through NMDA, TRPA1, and TRPM3 receptor systems. Keywords: acute, neuropathic, orofacial pain, rodents