New Trigeminal Stimulation Technique with Dorsal Root Ganglion Stimulation Electrode and Maxillary Fixation: Technique Description.

BACKGROUND: Trigeminal neuralgia is considered the worst pain a human being can experience. Initial treatment uses anticonvulsant sodium channel blockers, which relieve pain in approximately 70% of patients. In refractory cases, it is possible to perform ablative treatments, decompressive surgeries, and neuromodulatory techniques. METHODS: This report describes the treatment of a patient with refractory trigeminal neuralgia who continued to have a painful clinical presentation after four surgical procedures and three ablative procedures. The patient presented with severe pain (verbal numerical scale between 9 and 10), manifesting an evident suicidal ideation. A dorsal root ganglion (DRG) stimulation electrode was implanted in the trigeminal ganglion through intraoral puncture with maxillary fixation of the electrode, in order to minimize the chances of displacement. The test phase consisted of implanting a quadripolar electrode for DRG stimulation through puncture lateral to the buccal rim in a fluoroscopic coaxial view. The electrode was fixed to the skin and maintained for 5 days, during which the patient remained completely pain free. After the 5-day test period, the definitive stimulation electrode was implanted, this time with intraoral puncture and maxillary electrode fixation. RESULTS: The patient remains pain free in the 3-month follow-up, with no displacement of the electrode. CONCLUSIONS: The DRG electrode may be considered a therapeutic option in patients with severe trigeminal neuralgia. Controlled studies must be performed to determine the efficacy and safety of the method.

Prevalence and characteristics of headache attributed to ingestion or inhalation of a cold stimulus (HICS): A cross-sectional study.

BACKGROUND: Headache attributed to ingestion or inhalation of a cold stimulus (HICS), colloquially called ice-cream headache, is a common form of a primary headache in adults and children. However, previous studies on adults are limited due to the small number of patients. Furthermore, most of the subjects in previous studies had a history of other primary headaches. METHODS: Biographic data, clinical criteria of HICS and prevalence of primary headache were collected by a standardized questionnaire. A total of 1213 questionnaires were distributed; the return rate was 51.9% (n = 629); 618 questionnaires could be analyzed. RESULTS: In a cohort of 618 people aged between 17-63 years (females: n = 426, 68.9%), the prevalence of HICS was 51.3% (317 out of 618). There was no difference between men and women (51.3% vs. 51.6%). The duration of HICS was shorter than 30 sec in 92.7%. In the HICS group, localization of the pain was occipital in 17%. Trigemino-autonomic symptoms occurred in 22%, and visual phenomena (e.g. flickering lights, spots or lines) were reported by 18% of the HICS group. The pain intensity, but not the prevalence of HICS, was higher when tension-type headache and migraine or both were present as co-morbid primary headaches (Numeric Rating Scale (NRS) 4.58 and 6.54, p = 0.006). There was no higher risk of participants with migraine getting HICS than for those who did not have migraine (odds ratio = 1.17, 95% confidence interval (CI) 0.75-1.83; p = 0.496). CONCLUSION: The results of this study modified the current criteria for HICS in the ICHD-3 regarding duration and localization. In addition, accompanying symptoms in about one fifth of the participants are not mentioned in the ICHD-3. Neither migraine nor tension-type headache seems to be a risk factor for HICS. However, accompanying symptoms in HICS are more frequent in subjects with another primary headache than in those without such a headache.

Migraine neuroscience: from experimental models to target therapy.

Migraine sciences have witnessed tremendous advances in recent years. Pre-clinical and clinical experimental models have contributed significantly to provide useful insights into the brain structures that mediate migraine attacks. These models have contributed to elucidate the role of neurotransmission pathways and to identify the role of important molecules within the complex network involved in migraine pathogenesis. The contribution and efforts of several research groups from all over the world has ultimately lead to the generation of novel therapeutic approaches, specifically targeted for the prevention of migraine attacks, the monoclonal antibodies directed against calcitonin gene-related peptide or its receptor. These drugs have been validated in randomized placebo-controlled trials and are now ready to improve the lives of a large multitude of migraine sufferers. Others are in the pipeline and will soon be available.

Functional interictal changes of pain processing in migraine with ictal cutaneous allodynia.

Objective A prospective clinical imaging study has been conducted to investigate pain processing functional pathways during trigeminal heat stimulation (THS) in patients with migraine without aura experiencing ictal cutaneous allodynia (CA) (MwoA CA+). Methods Using whole-brain BOLD-fMRI, functional response to THS at three different intensities (41°, 51° and 53℃) was investigated interictally in 20 adult MwoA CA+ patients compared with 20 MwoA patients without ictal CA (MwoA CA-) and 20 healthy controls (HCs). Secondary analyses evaluated associations between BOLD signal change and clinical features of migraine. Results During moderate-noxious THS (51℃), we observed a significantly greater activation in (a) the anterior cingulate cortex in MwoA CA+ patients compared to HCs and (b) the middle frontal gyrus in MwoA CA+ patients compared to both MwoA CA- patients and HCs. Furthermore, during high-noxious THS (53℃) a significantly decreased activation in the secondary somatosensory cortices was observed in (a) MwoA CA- patients compared to both MwoA CA+ patients and HCs and (b) MwoA CA+ patients compared to HCs. CA severity was positively correlated with the secondary somatosensory cortices activation. Conclusions Our findings suggest that CA may be subtended by both a dysfunctional analgesic compensatory mechanism and an abnormal internal representation of pain in migraine patients.

Experimental provocation of 'ice-cream headache' by ice cubes and ice water.

Background There are various studies on experimentally provoked 'ice-cream headache' or 'headache attributed to ingestion or inhalation of a cold stimulus' (HICS) using different provocation protocols. The aim of this study was to compare two provocation protocols. Methods Ice cubes pressed to the palate and fast ingestion of ice water were used to provoke HICS and clinical features were compared. Results The ice-water stimulus provoked HICS significantly more often than the ice-cube stimulus (9/77 vs. 39/77). Ice-water-provoked HICS had a significantly shorter latency (median 15 s, range 4-97 s vs. median 68 s, range 27-96 s). There was no difference in pain localisation. Character after ice-cube stimulation was predominantly described as pressing and after ice-water stimulation as stabbing. A second HICS followed in 10/39 (26%) of the headaches provoked by ice water. Lacrimation occurred significantly more often in volunteers with than in those without HICS. Discussion HICS provoked by ice water was more frequent, had a shorter latency, different pain character and higher pain intensity than HICS provoked by ice cubes. The finding of two subsequent HICS attacks in the same volunteers supports the notion that two types of HICS exist. Lacrimation during HICS indicates involvement of the trigeminal-autonomic reflex.

Physiopathology of Migraine: What Have We Learned from Functional Imaging?

PURPOSE OF REVIEW: This review aims to provide an overview of the most recent and significant functional neuroimaging studies which have clarified the complex mechanisms underlying migraine pathophysiology. RECENT FINDINGS: The recent data allow us to overcome the concept of a migraine generator suggesting that functional networks abnormalities may lead to changes in different brain area activities and consequent reduced migraine thresholds susceptibility, likely associated with higher migraine severity and burden. Although functional magnetic resonance imaging studies have allowed recognition of several migraine mechanisms, its pathophysiology is not completely understood and is still a matter of research. Nevertheless, in recent years, functional magnetic resonance imaging studies have allowed us to implement our knowledge of migraine pathophysiology. The pivotal role of both the brainstem and the hippocampus in the first phase of a migraine attack, the involvement of limbic pathway in the constitution of a migrainous pain network, the disrupted functional connectivity in cognitive brain networks, as well as the abnormal function of the visual network in patients with migraine with aura are the main milestones in migraine imaging achieved through functional imaging advances. We believe that further studies based on combined functional and structural techniques and the investigation of the different phases of migraine cycle may represent an efficient methodological approach for comprehensively looking into the migrainous brain secrets.

Central effects of trigeminal electrical stimulation.

This is a review of the literature on the main neuromodulation techniques, focusing on the possibility of introducing sensory threshold ULFTENS into them. Electro neuromodulation techniques have been in use for many years as promising methods of therapy for cognitive and emotional disorders. One of the most widely used forms of stimulation for orofacial pain is transcutaneous trigeminal stimulation on three levels: supraorbital area, dorsal surface of the tongue, and anterior skin area of the tragus. The purpose of this review is to trigger interest on using dental ULFTENS as an additional trigeminal neurostimulation and neuromodulation technique in the context of TMD. In particular, we point out the possibility of using ULFTENS at a lower activation level than that required to trigger a muscle contraction that is capable of triggering effects at the level of the autonomic nervous system, with extreme ease of execution and few side effects.

Percutaneous Trigeminal Nerve Stimulation for Persistent Idiopathic Facial Pain: A Case Series.

BACKGROUND: Persistent idiopathic facial pain (PIFP) can be refractory to conventional management approaches. Neuromodulatory procedures such as percutaneous trigeminal nerve stimulation (TNS) have been sparsely reported as potential treatment options for amelioration of debilitating refractory pain associated with PIFP. The present study investigated the use of percutaneous TNS in a series of patients with PIFP to evaluate the potential efficacy of pain relief. METHODS: We performed a retrospective medical record review for patients with PIFP who had presented to Emory University Hospital and had undergone TNS for PIFP. The primary outcomes were postoperative pain using the visual analog scale (VAS) for pain and morphine equivalent use. Descriptive statistics, mean ± standard deviation, and the nonparametric Wilcoxon sign rank test were used, as appropriate. A P value of <0.05 was considered statistically significant. RESULTS: A total of 23 patients underwent percutaneous TNS for PIFP. Of the 23 patients, 20 (86.9%) reported a >50% improvement after trial stimulation. Of the patients who had received permanent TNS implants, 13 of 17 (76.4%) had VAS scores available. For these patients, the mean preoperative VAS score had decreased from 5.69 ± 2.09 to 0.15 ± 0.55 postoperatively. The VAS scores displayed a statistically significant decrease after TNS (P = 0.0014). A subset of 9 patients with available data also demonstrated a significant reduction in morphine equivalent use after TNS (before, 50.54 ± 51.30; after, 25.83 ± 33.58; P = 0.048). CONCLUSION: The results from the present study have indicated that percutaneous stimulation of the trigeminal nerve is efficacious in the treatment of PIFP and can significantly decrease morphine equivalent use. Further longitudinal studies are required to validate our results.

Time-course of trigeminal versus olfactory stimulation: evidence from chemosensory evoked potentials.

Habituation of responses to chemosensory signals has been explored in many ways. Strong habituation and adaptation processes can be observed at the various levels of processing. For example, with repeated exposure, amplitudes of chemosensory event-related potentials (ERP) decrease over time. However, long-term habituation has not been investigated so far and investigations of differences in habituation between trigeminal and olfactory ERPs are very rare. The present study investigated habituation over a period of approximately 80 min for two olfactory and one trigeminal stimulus, respectively. Habituation was examined analyzing the N1 and P2 amplitudes and latencies of chemosensory ERPs and intensity ratings. It was shown that amplitudes of both components - and intensity ratings - decreased from the first to the last block. Concerning ERP latencies no effects of habituation were seen. Amplitudes of trigeminal ERPs diminished faster than amplitudes of olfactory ERPs, indicating that the habituation of trigeminal ERPs is stronger than habituation of olfactory ERPs. Amplitudes of trigeminal ERPs were generally higher than amplitudes of olfactory ERPs, as it has been shown in various studies before. The results reflect relatively selective central changes in response to chemosensory stimuli over time.

Transcutaneous vagus and trigeminal nerve stimulation for neuropsychiatric disorders: a systematic review / Estimulação transcutânea do nervo vago e do nervo trigêmeo para o tratamento de distúrbios neuropsiquiátricos: revisão sistemática

We reviewed trigeminal nerve stimulation (TNS) and transcutaneous vagus nerve stimulation (tVNS). All techniques have shown preliminary promising results, although the results are mixed. Method: We performed a systematic review of the Medline and Embase databases, with no constraint to dates, through June 2013. The keywords were [(1) trigeminal nerve stimulation OR (2) cranial nerve OR (3) trigemin* OR (4) transcutaneous VNS OR (5) transcutaneous cranial nerve stimulation] and (6) mental disorders. Results: We included four preclinical and clinical five studies on TNS. All clinical data were based on open-label studies with small samples, which diminished the external validity of the results, thus reflecting the modest impact of TNS in current clinical practice. Of the tVNS clinical trials, three assessed physiological features in healthy volunteers, and one examined patients with epilepsy. Conclusion: TNS and tVNS improve treatment of particular neuropsychiatric disorders such as depression. .

O uso de estimulação de nervos cranianos de maneira transcutânea tem sido uma estratégia em desenvolvimento recente. Diferentes estudos apontam para resultados clínicos favoráveis no tratamento de diferentes quadros neuropsiquiátricos. Método: Revisão sistemática da literatura com base nas bibliotecas eletrônicas Medline e Embase, sem restrição de data inicial, até agosto de 2013. Os termos de busca utilizados foram [(1) trigeminal nerve stimulation OR (2) cranial nerve OR (3) trigemin* OR (4) transcutaneous VNS OR (5) transcutaneous cranial nerve stimulation] and (6) mental disorders. Resultados: Incluímos quatro estudos pré-clinicos e cinco estudos clínicos abordando estimulação do nervo trigêmeo. Todos os estudos foram abertos, com pequenas amostras, o que reduz a validade externa dos dados, refletindo a ainda incipiente atuação da técnica, apesar de promissora. Considerando-se a estimulação do nervo vago, três artigos avaliaram aspectos fisiológicos em voluntários saudáveis e um artigo estudou pacientes com epilepsia. Conclusão: As estratégias de estimulação transcutânea de nervos cranianos, apesar de incipiente, tem demonstrado resultados clínicos favoráveis no tratamento de distúrbios neuropsiquiátricos. .