Somatosensory investigation of patients with orofacial pain compared with controls.

The objective of this study was to investigate the sensorial characteristics of orofacial pain in patients compared with control subjects. A total of 336 subjects (282 patients and 54 control subjects) were evaluated to identify their thermal (cold and warm), tactile, and pain thresholds. Numbness was reported by 61.7% of the patients (p<0.001). Patients with trigeminal postherpetic neuralgia and burning mouth syndrome showed loss of thermal perception; patients with postherpetic neuralgia, burning mouth syndrome, and posttraumatic painful neuropathy had a decrease in tactile perception compared with the control subjects (p<0.001). In conclusion, other sensorial modalities besides pain are affected by neuropathic orofacial pain; these findings can help in the understanding of the pathophysiological mechanisms in orofacial pain.

Association between craniofacial pain complaints, somatoform symptoms and chronic diseases.

OBJECTIVE: This case-control study aimed to investigate associations between craniofacial pain complaints, somatoform symptoms and chronic diseases. DESIGN: 306 subjects were included in this study (174 patients and 132 healthy subjects). The evaluation consisted of demographic data, number of functional and nonfunctional chronic diseases, medications, somatoform symptoms (xerostomia, dry mucosa, numbness, gastrointestinal complaints), and pain complaints with associated characteristics (number of pain areas, sensation of tired face, bruxism, sleep disturbances, masticatory musculoskeletal evaluation). Statistical analysis included descriptive data, tested with chi-square, Fisher's exact, nonparametric Kolmogorov-Smirnoff, Student's t-test, Pearson's coefficient, two-steps cluster classification, multivariate linear and LASSO regressions. RESULTS: Functional disorders were prevalent in 111 (63.8 %) patients with facial pain. They were taking more medication (p < 0.001) and had more sleep disturbances (p < 0.001), higher xerostomia scores (p < 0.001) and more gastrointestinal complaints (p < 0.001) than controls. There was a positive correlation between the functional score and the number of cranial areas with headache (R2 = 0.266, <0.001). The regression models for facial pain (R2 = 0.632), craniofacial pain (R2 = 0.623) and headache (R2 = 0.252) showed significant dependency of functional disorders (p < 0.001). CONCLUSION: craniofacial pain was associated with functional diseases and somatoform symptoms. This association needs further investigation to understand the role of those disorders in craniofacial pain, considering that pain complaints are common somatoform and functional symptoms.

Sensory characteristics according to chronic diseases and chronic pain in adults: cross-sectional study.

Aim: To investigate somatosensory, gustative and olfactory characteristics of subjects according to their chronic diseases and the presence of chronic pain complaints. Materials & methods: A total of 254 chronic pain patients and 52 healthy subjects were evaluated with a clinical and sensory systematized evaluation. Statistical analysis consisted of Fisher's exact, Student's t-tests, Pearson's co-efficient and multivariate nonlinear/logistic regressions. Results: Patients had more chronic diseases (p < 0.001) than healthy subjects. Chronic pain was associated with vibratory hypoesthesia (p = 0.047) and sour hypergeusia (p = 0.001) and several chronic diseases correlated with sensory features. Hyposmia was strongly associated with chronic pain symptoms, chronic diseases and cardiovascular disease. Conclusion: The sensory findings observed suggest the need for further investigation about the overlap between the olfactory function, pain chronification, chronic diseases and cognitive impairment in these patients.

Balloon compression vs radiofrequency for primary trigeminal neuralgia: a randomized, controlled trial.

ABSTRACT: Surgical procedures are necessary in up to 50% of trigeminal neuralgia patients. Although radiofrequency (RF) is more widely used, it is associated with high intraprocedural costs and long technical learning time. Other simpler procedures such as balloon compression (BC) require a lower training period and have significant lower costs. We evaluated the effects of BC and RF in pain control in primary trigeminal neuralgia in a randomized, double-blinded, head-to-head trial. Individuals were randomly allocated in 1 of 2 groups: BC and RF. Throughout pain, psychological and quality of life measurements were performed at baseline and after surgery. The main outcome was the worst pain in the last 24 hours (0-10) at 6 months postoperatively. After the inclusion of half of the estimated sample, a preplanned interim analysis was performed when 33 patients (62.1 ± 9.4 y.) completed the study. Pain intensity (confidence interval [CI] 95% 0.6 to 3.8, and -0.6 to 2.2, for BC and RF) did not significantly differ. Complications, interference of pain in daily life (CI 95% -0.1 to 2.3 and -0.4 to 2.3, for BC and RF), neuropathic pain symptoms (CI 95% 1.7 to 3.6 and 3.0 to 5.7, for BC and RF), mood (CI 95% 4.8 to 11.5 and 5.5 to 15.1, BC and RF, respectively), medication use, and quality of life (CI 95% 80.4 to 93.1 and 83.9 to 94.2, for BC and RF) were also not different. Radiofrequency presented more paresthetic symptoms than BC at 30 days after intervention. Based on these results, the study was halted due to futility because BC was not superior to RF.

Insular and anterior cingulate cortex deep stimulation for central neuropathic pain: Disassembling the percept of pain.

OBJECTIVE: To compare the analgesic effects of stimulation of the anterior cingulate cortex (ACC) or the posterior superior insula (PSI) against sham deep (d) repetitive (r) transcranial magnetic stimulation (TMS) in patients with central neuropathic pain (CNP) after stroke or spinal cord injury in a randomized, double-blinded, sham-controlled, 3-arm parallel study. METHODS: Participants were randomly allocated into the active PSI-rTMS, ACC-rTMS, sham-PSI-rTMS, or sham-ACC-rTMS arms. Stimulations were performed for 12 weeks, and a comprehensive clinical and pain assessment, psychophysics, and cortical excitability measurements were performed at baseline and during treatment. The main outcome of the study was pain intensity (numeric rating scale [NRS]) after the last stimulation session. RESULTS: Ninety-eight patients (age 55.02 ± 12.13 years) completed the study. NRS score was not significantly different between groups at the end of the study. Active rTMS treatments had no significant effects on pain interference with daily activities, pain dimensions, neuropathic pain symptoms, mood, medication use, cortical excitability measurements, or quality of life. Heat pain threshold was significantly increased after treatment in the PSI-dTMS group from baseline (1.58, 95% confidence interval [CI] 0.09-3.06]) compared to sham-dTMS (-1.02, 95% CI -2.10 to 0.04, p = 0.014), and ACC-dTMS caused a significant decrease in anxiety scores (-2.96, 95% CI -4.1 to -1.7]) compared to sham-dTMS (-0.78, 95% CI -1.9 to 0.3; p = 0.018). CONCLUSIONS: ACC- and PSI-dTMS were not different from sham-dTMS for pain relief in CNP despite a significant antinociceptive effect after insular stimulation and anxiolytic effects of ACC-dTMS. These results showed that the different dimensions of pain can be modulated in humans noninvasively by directly stimulating deeper SNC cortical structures without necessarily affecting clinical pain per se. CLINICALTRIALSGOV IDENTIFIER: NCT01932905.

Acupuncture treatment for idiopathic trigeminal neuralgia: A longitudinal case-control double blinded study.

OBJECTIVE: To evaluate the treatment effect of acupuncture on patients with idiopathic trigeminal neuralgia (ITN) by case-control longitudinal blinded study. METHODS: Sixty ITN patients and 30 healthy subjects were included. The ITN patients were randomly assigned to acupuncture group (15 cases), sham-acupuncture group (15 cases) and carbamazepine group (30 cases), respectively. Clinical orofacial evaluation (including pain intensity and medication doses), research diagnostic criteria for temporomandibular disorders (RDC/TMD) and Helkimo indexes (for functional evaluation of the masticatory system), and quantitative sensory testing for sensory thresholds (gustative, olfactory, cold, warm, touch, vibration and superficial and deep pain) were evaluated before treatment, immediately after treatment, and 6 months after treatment. RESULTS: The mean pain intensity by the Visual Analogue Scale only decreased in the acupuncture group at the last evaluation (P=0.012). Patients in the sham-acupuncture group had an increase in carbamazepine doses according to the prescriptions (P<0.01). There was a reduction in secondary myofascial pain and mandibular limitations at the acupuncture and sham-acupuncture groups, however only the acupuncture group kept the changes after 6 months (P<0.01, P=0.023). There was a decrease in mechanical thresholds in the acupuncture group (tactile, P<0.01; vibration, P=0.027) and an increase in deep pain thresholds in both acupuncture and sham-acupuncture groups (P=0.013). CONCLUSIONS: Acupuncture can be an option in the treatment of ITN due to its analgesic effect in both ITN and secondary myofascial pain associated with it.

Functional and sensory evaluation of patients with idiopathic trigeminal neuralgia: comparison with controls.

BACKGROUND: Idiopathic trigeminal neuralgia (ITN) can be associated with orofacial and sensory comorbidities. OBJECTIVE: To evaluate the masticatory functional and sensory characteristics of patients with ITN compared with controls. METHODS: We enrolled 119 patients and 30 healthy controls. They were evaluated with a systematic protocol: clinical orofacial evaluation questionnaire; a systematic approach of the mandibular function and the investigation of musculoskeletal comorbidities by the research diagnostic criteria for temporomandibular disorders (RDC/TMD) and the Helkimo indexes; and quantitative sensory testing (corneal reflex and gustative, olfactory, thermal, mechanical and pain thresholds). RESULTS: The study group had more loss of vertical dimension than the controls (p=0.011) and restriction of the maximum mouth opening (p=0.024); they had more pain on mandibular movements (p=0.001), limitation of mandibular function (p<0.001), masticatory discomfort (p<0.001) and myofascial pain (p=0.001). Occlusion Helkimo index was lower in controls than patients. The study group had high tactile (p=0.025), warm (p=0.020) and cold (p=0.003) thresholds. CONCLUSION: ITN may cause severe mandibular limitations that can be associated with the pain episodes and with sensory abnormalities. These findings indicate the affection of small and large nerve fibers and support the neuropathic nature of ITN. Sensory alterations can be part of the natural history of ITN and can be associated with the previous treatments including medication. They cause a high impact in quality of life.

Sensory abnormalities and masticatory function after microvascular decompression or balloon compression for trigeminal neuralgia compared with carbamazepine and healthy controls.

OBJECT: Idiopathic trigeminal neuralgia (iTN) is a neurological condition treated with pharmacotherapy or neurosurgery. There is a lack of comparative papers regarding the outcomes of neurosurgery in patients with iTN. The objective of this study was to investigate sensory thresholds and masticatory function in 78 patients with iTN who underwent microvascular decompression (MVD) or balloon compression (BC), and compare these treatments with carbamazepine and 30 untreated healthy controls. METHODS: The authors conducted a case-controlled longitudinal study. Patients were referred to 1 of 3 groups: MVD, BC, or carbamazepine. All patients were evaluated before and after treatment with a systematic protocol composed of a clinical orofacial questionnaire, Research Diagnostic Criteria for temporomandibular disorders, Helkimo indices, and a quantitative sensory-testing protocol (gustative, olfactory, cold, warm, touch, vibration, superficial, and deep pain thresholds). RESULTS: Both MVD and BC were effective at reducing pain intensity (p = 0.012) and carbamazepine doses (p < 0.001). Myofascial and articular complaints decreased in both groups (p < 0.001), but only the patients in the MVD group showed improvement in Helkimo indices (p < 0.003). Patients who underwent MVD also showed an increase in sweet (p = 0.014) and salty (p = 0.003) thresholds. The sour threshold decreased (p = 0.003) and cold and warm thresholds increased (p < 0.001) in patients after MVD and BC, but only the patients who underwent BC had an increase in touch threshold (p < 0.001). CONCLUSIONS: Microvascular decompression and BC resulted in a reduction in myofascial and jaw articular complaints, and the impact on masticatory function according to Helkimo indices was greater after BC than MVD. MVD resulted in more gustative alterations, and both procedures caused impairment in thermal thresholds (warm and cold). However, only BC also affected touch perception. The sensorial and motor deficits after BC need to be included as targets directly associated with the success of the surgery and need to be assessed and relieved as goals in the treatment of iTN.

High prevalence of orofacial complaints in patients with fibromyalgia: a case-control study.

OBJECTIVE: The aim of this study was to investigate the orofacial complaints and characteristics of patients with fibromyalgia syndrome (FS) compared with controls. STUDY DESIGN: We evaluated 25 patients diagnosed with FS compared with 25 gender- and age-matched controls by using a detailed clinical protocol for orofacial pain diagnosis and dental examination. RESULTS: FS patients had a higher frequency of temporomandibular disorders (TMD), masticatory complaints, pain with mandibular movements, and pain upon palpation of the head and neck area. There were no significant differences related to the dental exam. CONCLUSIONS: Orofacial complaints including TMD may be present either as symptoms of FS or as a comorbidity associated with this condition. A comprehensive evaluation of patients with FS is necessary to identify the need for specific treatments for orofacial complaints. Future studies, especially those with longitudinal design, should clarify whether a cause-effect relationship exists between orofacial complaints and fibromyalgia.

Subthalamic deep brain stimulation modulates small fiber-dependent sensory thresholds in Parkinson's disease.

The effects of deep brain stimulation of the subthalamic nucleus on nonmotor symptoms of Parkinson's disease (PD) rarely have been investigated. Among these, sensory disturbances, including chronic pain (CP), are frequent in these patients. The aim of this study was to evaluate the changes induced by deep brain stimulation in the perception of sensory stimuli, either noxious or innocuous, mediated by small or large nerve fibers. Sensory detection and pain thresholds were assessed in 25 PD patients all in the off-medication condition with the stimulator turned on or off (on- and off-stimulation conditions, respectively). The relationship between the changes induced by surgery on quantitative sensory testing, spontaneous CP, and motor abilities were studied. Quantitative sensory test results obtained in PD patients were compared with those of age-matched healthy subjects. Chronic pain was present in 72% of patients before vs 36% after surgery (P=.019). Compared with healthy subjects, PD patients had an increased sensitivity to innocuous thermal stimuli and mechanical pain, but a reduced sensitivity to innocuous mechanical stimuli. In addition, they had an increased pain rating when painful thermal stimuli were applied, particularly in the off-stimulation condition. In the on-stimulation condition, there was an increased sensitivity to innocuous thermal stimuli but a reduced sensitivity to mechanical or thermal pain. Pain provoked by thermal stimuli was reduced when the stimulator was turned on. Motor improvement positively correlated with changes in warm detection and heat pain thresholds. Subthalamic nucleus deep brain stimulation contributes to relieve pain associated with PD and specifically modulates small fiber-mediated sensations.

Xerostomia and salivary flow in patients with orofacial pain compared with controls.

OBJECTIVES: Pain in the orofacial region is frequently reported by patients in dental and medical offices. Facial pain, headache, masticatory abnormalities and other complaints often become chronic and may be associated with local disturbances, such as xerostomia and teeth abnormalities. The objective of this study was to investigate salivary flow and xerostomia in patients with orofacial pain. DESIGN: This was a case-control study; we evaluated 82 patients with chronic orofacial pain compared with 56 healthy subjects using a Clinical Pain Questionnaire (pain characteristics, duration, intensity and descriptors), complete dental examination (including static and dynamic evaluation of the jaw) and a Xerostomia Inventory. The salivary flow was quantitatively evaluated. Data was compared through Pearson's chi-square, Fisher's exact, analysis of variance (ANOVA) 1 factor and Mann-Whitney tests. RESULTS: Patients often had temporomandibular disorder (TMD) (P=0.001) and pain during facial (P<0.001) and neck palpation (P=0.002). There were no differences in dental examination or other structural aspects of the jaw between the groups. There were more complaints associated with xerostomia in the study group, including burning sensation in the oral mucosa (P=0.003), in the throat (P=0.035) and in the stomach (P=0.050). Patients had lower salivary flow (P=0.008). CONCLUSIONS: Orofacial pain patients need to be evaluated with regard to their salivary function, which was often found abnormal in this sample and may have contributed to the complaints of these patients. Assessing salivary flow and xerostomia may help in the treatment of chronic orofacial pain.