Effects of Non-Invasive Neuromodulation of the Vagus Nerve for the Management of Cluster Headache: A Systematic Review.

BACKGROUND: Cluster headache (CH) is a type of headache that has a global prevalence of 0.5-3/1000 people, provokes severe, strictly unilateral pain through the first branch of the trigeminal nerve, and is associated with observable autonomous responses. CH provokes intense pain and decreases quality of life. OBJECTIVE: In this study, we aimed to carry out a systematic review of the effectiveness of non-invasive neuromodulation of the vagus nerve in patients with cluster headaches, which was registered on PROSPERO No. CRD42021265126. METHODS: Six databases were used from their date of inception to February 2023 to obtain studies with the group intervention of non-invasive neuromodulation of the vagus nerve for cluster headache, with outcomes based on pain attacks, duration, and disabilities. Data on the subjects, group intervention, main outcomes, and results were collected by two authors. RESULTS: The search provided 1003 articles, with three clinical trials being eligible for inclusion in the review. The methodological quality scores ranged from 6 to 8 points (mean: 7.3, SD: 0.8) out of a maximum of 10 points. The post-treatment results showed some positive effects using n-VNS as a treatment for cluster headache, more specifically regarding cervical neuromodulation of the vagus nerve. CONCLUSIONS: The systematic review found moderate-to-high-quality evidence supporting that n-VNS and cervical n-VNS may have some positive effects at the end of the treatment being effective to relieve the frequency and intensity of cluster headaches. The poor quantity of studies available and the lack of homogeneity in the study protocols did not allow the pooling of data for a meta-analysis.

Management of auricular transcutaneous neuromodulation and electro-acupuncture of the vagus nerve for chronic migraine: a systematic review.

Background: Migraine is a type of primary headache that is accompanied by symptoms such as nausea, vomiting, or sensitivity to light and sound. Objective: The aim of this study was to conduct a systematic review on the effectiveness of non-invasive neuromodulation, auricular transcutaneous vagus nerve stimulation (at-VNS), and electro-ear acupuncture of the vagus nerve in patients with migraine headaches. Methods: Six databases were searched from inception to 15 June 2022 for clinical trials, in which at least one group received any form of non-invasive neuromodulation of the vagus nerve for managing migraine with outcomes collected on pain intensity and related disability. Data, including participants, interventions, blinding strategy, outcomes, and results, were extracted by two reviewers. The methodological quality was assessed with the PEDro scale, ROB, and Oxford scale. Results: The search identified 1,117 publications with nine trials eligible for inclusion in the review. The methodological quality scores ranged from 6 to 8 (mean: 7.3, SD: 0.8) points. Low-quality evidence suggests some positive clinical effects for the treatment of chronic migraine with 1 Hz with at-VNS and ear-electro-acupuncture compared with the control group at post-treatment. Some of the studies provided evidence of the relationship between chronic migraine and a possible positive effect as a treatment with at-VNS and the neurophysiological effects using fMRI. Six of the studies provided evidence using fMRI of the relationship between chronic migraine and a possible positive effect as a treatment with at-VNS and the neurophysiological effects. Regarding all included studies, the level of evidence with the Oxford scale was level 1 (11.17%), six studies were graded as level 2 (66.66%), and two studies were graded as level 3 (22.2%). With the PEDro score, five studies got a low methodological score < 5 and only four got a score superior to 5, being highly methodological quality studies. For ROB, most of the studies were high risk and only a few of them received a low risk of bias. The pain intensity, migraine attacks, frequency, and duration were measured by three studies with positive results at post-treatment. And only 7% reported adverse events using at-VNS. All studies reported results at a post-treatment period in their respective main outcomes. And all studies with fMRI provided strong evidence of the relationship between the Locus Coeruleus, Frontal Cortex, and other superior brain areas with the auricular branch of the Vagus nerve with at-VNS. Conclusion: Some positive effects regarding the effect of non-invasive neuromodulation, auricular transcutaneous vagus nerve stimulation (at-VNS), and electro-ear acupuncture of the vagus nerve on migraine is reported in the current literature, but there are not enough data to obtain strong conclusions. Systematic review registration: This systematic review was registered in the PROSPERO database (registration number: CRD42021265126).

Effects of Non-Invasive Neuromodulation of the Vagus Nerve for Management of Tinnitus: A Systematic Review with Meta-Analysis.

BACKGROUND: Tinnitus is the perception of sound in the absence of actual external stimuli. Other associated symptoms include frustration, annoyance, anxiety, depression, stress, cognitive dysfunction, insomnia, or emotional exhaustion. OBJECTIVE: In this study, we aimed to conduct a systematic review and meta-analysis on the effectiveness of the non-invasive neuromodulation of the vagus nerve in patients with tinnitus. METHODS: Six databases were searched from their date of inception to 15 June 2022 to identify clinical trials in which at least one group received any form of non-invasive neuromodulation of the vagus nerve for tinnitus management, with outcomes based on annoyance and related disability. Data on participants, interventions, blinding strategies, assessment outcomes, and results were extracted by two reviewers. RESULTS: The search identified 183 articles with five clinical trials eligible for inclusion in the review and four for the meta-analysis. The methodological quality scores ranged from 6 to 8 (mean: 7.3, SD: 0.8) points. The meta-analysis identified a significant positive effect on THI post-treatment for unilateral auricular stimulation (hg = 0.69, 95% CI 0.06, 1.32) or transcutaneous nerve stimulation (hg = 0.51, 95% CI 0.1, 0.9) compared with a comparative group. No effect on loudness intensity was observed. CONCLUSION: The results of the meta-analysis suggest that the application of the non-invasive neuromodulation of the vagus nerve has a positive effect post-treatment in terms of related disability in patients with tinnitus, although its clinical relevance is low. No firm conclusions about the effect of the non-invasive neuromodulation of the vagus nerve on tinnitus are available based on the current literature.

Morphological Changes of the Suboccipital Musculature in Women with Myofascial Temporomandibular Pain: A Case-Control Study.

Temporomandibular disorder (TMD) is an umbrella term including pain problems involving the cranio-cervical region. It has been suggested that patients with TMD also exhibit cervical spine disturbances. Evidence suggests the presence of morphological changes in the deep cervical muscles in individuals with headaches. The objective of this study was to compare the morphology of the suboccipital muscles between women with TMD and healthy controls. An observational, cross-sectional case-control study was conducted. An ultrasound examination of the suboccipital musculature (rectus capitis posterior minor, rectus capitis posterior major, oblique capitis superior, oblique capitis inferior) was conducted in 20 women with myofascial TMD and 20 matched controls. The cross-sectional area (CSA), perimeter, depth, width, and length of each muscle were calculated by a blinded assessor. The results revealed that women with myofascial TMD pain exhibited bilaterally reduced thickness, CSA, and perimeter in all the suboccipital muscles when compared with healthy women. The width and depth of the suboccipital musculature were similar between women with myofascial TMD and pain-free controls. This study found morphological changes in the suboccipital muscles in women with myofascial TMD pain. These changes can be related to muscle atrophy and are similar to those previously found in women with headaches. Future studies are required to investigate the clinical relevance of these findings by determining if the specific treatment of these muscles could help clinically patients with myofascial TMD.

Cadaveric and in vivo validation of needle placement in the medial pterygoid muscle.

BACKGROUND: Evidence suggests that medial pterygoid muscle plays an important role in temporomandibular pain. Therapeutic approaches targeting this muscle are needed. OBJECTIVE: To determine if a solid needle accurately penetrates the medial pterygoid muscle during the application of dry needling. DESIGN: A cadaveric and human descriptive study. METHODS: Needling insertion of the medial pterygoid was conducted in 5 fresh cadaver and 5 subjects with temporomandibular pain. Needling insertion was performed using a 40 mm needle inserted at the inferior angle of the mandibular bone. The needle was advanced from an inferior to superior direction into the medial pterygoid to a maximum depth of 30 mm. In cadavers, medial pterygoid placement was assessed by observation after resecting the superficial overlying tissues. In patients, medial pterygoid placement was assessed by self-reported pain referral during insertion. RESULTS: Accurate needle penetration of the medial pterygoid was observed in all fresh cadavers and pain referral was reported by 4/5 patients during needling insertion. CONCLUSION: Results from both cadavers and patients support the assertion that needling of the medial pterygoid can be accurately conducted.

Cadaveric and ultrasonographic validation of needling placement in the obliquus capitis inferior muscle.

BACKGROUND: Evidence suggests that suboccipital musculature plays an important role in headache. Proper therapeutic approaches targeting this muscle are needed. OBJECTIVE: Our aim was to determine with fresh cadavers and ultrasound imaging if a solid needle is able to properly penetrate the obliquus capitis inferior muscle during the application of dry needling. DESIGN: A cadaveric and human descriptive study. METHODS: Needling insertion and ultrasound imaging of the obliquus capitis inferior muscle was conducted on 10 pain-free healthy subjects and 5 fresh cadavers. Needling insertion was performed using a 40 mm needle inserted midway between the spinous process of C2 and transverse process of C1. The needle was advanced from a posterior to anterior direction into the obliquus capitis inferior muscle with an inferior-lateral angle to reach the lamina of C2. For the cadaveric study, the obliquus capitis inferior placement was verified by resecting the superficial upper trapezius, splenius capitis, and semispinalis capitis muscles. For ultrasographic study, a linear transducer was aligned with the long axis of the obliquus capitis inferior muscle after needle insertion. RESULTS: Both the cadaveric and ultrasonic studies showed that the needle penetrated the obliquus capitis inferior muscle during its insertion and that the tip of the needle rested against C2 laminae, thereby reaching the targeted muscle. CONCLUSION: This anatomical and ultrasound imaging study supports the assertion that needling insertion of the obliquus capitis inferior muscle can be properly conducted by an experienced clinician.

Cadaveric and Ultrasonographic Validation of Needling Placement in the Cervical Multifidus Muscle.

OBJECTIVE: The aim of this study was to determine if a needle is able to reach the cervical multifidus during the application of dry needling or acupuncture. METHODS: Dry needling and ultrasound imaging of cervical multifidi was conducted on 5 patients (age: 32 ± 5 years) with mechanical neck pain and on 2 fresh cadavers (age: 64 ± 1 years). Dry needling was done using a needle of 40 mm in length inserted perpendicular to the skin about 1 cm lateral to the spinous process at C3-C4. The needle was advanced from a posterior to anterior direction into the cervical multifidus with a slight inferior-medial angle (approximately 10°) to reach the vertebra lamina. For the cadaveric study, the multifidus was isolated by carefully resecting the superficial posterior cervical muscles: trapezius, splenius, and semispinalis. For the ultrasonographic study, a convex transducer was placed transversely over C3-C4 after the insertion of the needle into the muscle. RESULTS: The results of both the cadaveric and ultrasonic studies found that the needle does pierce the cervical multifidus muscle during insertion and that the tip of the needle rests properly against the vertebral laminae, thereby guarding the sensitive underlying spinal structures from damage. CONCLUSION: This anatomical and ultrasound imaging study supports that dry needling of the cervical multifidus could be conducted clinically.

Multimodal manual therapy vs. pharmacological care for management of tension type headache: A meta-analysis of randomized trials.

BACKGROUND: Manual therapies are generally requested by patients with tension type headache. OBJECTIVE: To compare the efficacy of multimodal manual therapy vs. pharmacological care for the management of tension type headache pain by conducting a meta-analysis of randomized controlled trials. METHODS: PubMed, MEDLINE, EMBASE, AMED, CINAHL, EBSCO, Cochrane Database of Systematic Reviews, Cochrane Collaboration Trials Register, PEDro and SCOPUS were searched from their inception until June 2014. All randomized controlled trials comparing any manual therapy vs. medication care for treating tension type headache adults were included. Data were extracted and methodological quality assessed independently by two reviewers. We pooled headache frequency as the main outcome and also intensity and duration. The weighted mean difference between manual therapy and pharmacological care was used to determine effect sizes. RESULTS: Five randomized controlled trials met our inclusion criteria and were included in the meta-analysis. Pooled analyses found that manual therapies were more effective than pharmacological care in reducing frequency (weighted mean difference -0.8036, 95% confidence interval -1.66 to -0.44; three trials), intensity (weighted mean difference -0.5974, 95% confidence interval -0.8875 to -0.3073; five trials) and duration (weighted mean difference -0.5558, 95% confidence interval -0.9124 to -0.1992; three trials) of the headache immediately after treatment. No differences were found at longer follow-up for headache intensity (weighted mean difference -0.3498, 95% confidence interval -1.106 to 0.407; three trials). CONCLUSION: Manual therapies were associated with moderate effectiveness at short term, but similar effectiveness at longer follow-up for reducing headache frequency, intensity and duration in tension type headache than pharmacological medical drug care. However, due to the heterogeneity of the interventions, these results should be considered with caution at this stage.

Cadaveric validation of dry needle placement in the lateral pterygoid muscle.

OBJECTIVE: The aim of this anatomical study was to determine if a needle is able to reach the lateral pterygoid muscle during the application of dry needling technique. METHODS: A dry needling approach using 2 needles of 50 to 60 mm in length, one inserted over the zygomatic process posterior at the obituary arch (for the superior head) and other inserted below the zygomatic process between the mandibular condyle and the coronoid process (for the inferior head), was proposed. A progressive dissection into 3 stages was conducted into 2 heads of fresh male cadavers. First, dry needling of the lateral pterygoid muscle was applied on the cadaver. Second, a block dissection containing the lateral pterygoid was harvested. Finally, the ramus of the mandible was sectioned by osteotomy to visualize the lateral pterygoid muscle with the needle placements. RESULTS: With the needles inserted into the cadaver, the block dissection revealed that the superior needle reached the superior (sphenoid) head of the lateral pterygoid muscle and the inferior needle reached the inferior (pterygoid) head of the muscle. At the final stage of the dissection, when the ramus of the mandible was sectioned by osteotomy, it was revealed that the superior needle entered into the belly of the superior head of the lateral pterygoid muscle. CONCLUSIONS: This anatomical study supports that dry needling technique for the lateral pterygoid muscle can be properly conducted with the proposed approach.