Sihler's staining of the anterior belly of digastric muscle for botulinum toxin injection.

PURPOSE: The anterior belly of the digastric muscle (ABDM) is the target of botulinum toxin injection; however, anatomical considerations related to the injection point are absent. This study used Sihler's staining to analyze the intramuscular nerve distribution of ABDM to identify the most effective botulinum toxin injection points. METHODS: We used 12 specimens from 6 embalmed cadavers in this study. The specimens were manually dissected to preserve the mylohyoid nerve and subjected to Sihler's staining. From the gnathion to and hyoid bone, the ABDM was divided into three equal parts, distinguishing the anterior, middle, and posterior thirds. RESULTS: Only a branch of the mylohyoid nerve entered the ABDM, and its entry point was located in the middle-third region in all cases. The nerve endings were concentrated in the middle third (100%), followed by the anterior third (58.3%) and were not observed in the posterior third. CONCLUSION: The landmarks used in this study (gnathion and hyoid bone) are easily palpable on the skin surface, allowing clinicians to target the most effective injection site (middle third of ABDM). These results provide scientific and anatomic evidence for injection points, and will aid in the management of ABDM injection procedures in clinical practice.

The Action of Botulinum Toxin A on the Sternocleidomastoid Muscle: An Experimental Study on Rats.

In this study, we aim to investigate the effective dose of botulinum neurotoxin A that results in paralysis of the sternocleidomastoid muscle for a minimum duration of 28 days in Wistar rats. This research is the first in a series of studies to investigate the value of botulinum toxin A in the healing of clavicle fractures through the temporary paralysis of the sternocleidomastoid. A surgical incision was made under general anaesthesia, and botulinum neurotoxin A in respective doses of 4 and 6 international units (IU) or normal saline in equivalent volumes were injected directly into the exposed muscle. Electromyography was conducted on days 0, 7, and 28 following substance administration to determine the extent of muscle paralysis. Electromyography on day 0 showed no paralysis in either group. Animals injected with neurotoxin all exhibited paralysis on days 7 and 28 that was weaker in the group injected with the smaller dose of 4 IU. One death occurred in the group injected with the higher dose (6 IU), whereas in the control group, no paralysis was seen. Botulinum neurotoxin A in a dose of 6 IU resulted in complete paralysis of the sternocleidomastoid in rats for a minimum of 28 days. A dose of 4 IU resulted in less potent paralysis but was safer in our research. Botulinum neurotoxin is a substance utilised in cosmetics and therapeutics for many years, yet research shows that its use can be expanded to target a wider range of pathologies. In this series of studies, we aim to explore the neurotoxin's applications on the treatment of clavicle fractures. To investigate this, we need to first establish the duration of its action on the sternocleidomastoid muscle.

Anatomo-sonographic identification of the longissimus capitis and splenius cervicis muscles: principles for possible application to ultrasound-guided botulinum toxin injections in cervical dystonia.

OBJECTIVE: The main objective of this study was to define and verify anatomo-sonographic landmarks for ultrasound-guided injection of botulinum toxin into the longissimus capitis (LC) and splenius cervicis (SC) muscles. METHODS AND RESULTS: After a preliminary work of anatomical description of the LC and SC muscles, we identified these muscles on two cadavers and then on a healthy volunteer using ultrasound and magnetic resonance imaging (MRI) to establish a radio-anatomical correlation. We defined an anatomo-sonographic landmark for the injection of each of these muscles. The correct positioning of vascular glue into the LC muscle and a metal clip into the SC muscle of a fresh cadaver as verified by dissection confirmed the utility of the selected landmarks. DISCUSSION: For the LC muscle, the intramuscular tendon of the cranial part of the muscle appears to be a reliable anatomical landmark. The ultrasound-guided injection can be performed within the cranial portion of the muscle, between the intra-muscular tendon and insertion into the mastoid process at dens of the axis level. For the SC muscle, the surface topographic landmarks of the spinous processes of the C4-C5 vertebrae and the muscle body of the levator scapulae muscle seem to be reliable landmarks. From these, the ultrasound-guided injection can be carried out laterally by transfixing the body of the levator scapulae. CONCLUSION: The study defined two cervical anatomo-sonographic landmarks for injecting the LC and SC muscles.

Local Anesthetic Block of the Anterior Scalene Muscle Increases Muscle Height in Patients With Neurogenic Thoracic Outlet Syndrome.

BACKGROUND: Local anesthetic (LA) blocks of the anterior scalene muscle are used to predict which patients with neurogenic thoracic outlet syndrome (TOS) may benefit from surgical decompression. The block is thought to work through both analgesic and muscle relaxation effects, but evidence of the latter is lacking. The aim of our study was to assess the effects of LA blocks on anterior scalene muscle anatomy as captured by magnetic resonance imaging (MRI). METHODS: Over a two-year period, a series of patients with neurogenic TOS underwent MRI-guided anterior scalene blocks with an LA. Patients underwent MRI both before injection and 30 minutes after injection. Anterior scalene muscle heights (measured from the superior border of the first rib to the top of C3 vertebrae) before and after injection were compared for the injected side and the noninjected (control) side, both overall and stratified by subjective patient response to injection. RESULTS: A total of 54 patients with neurogenic TOS were included. The median age was 39 years (interquartile range, 27-45), 61% were women, and 46% had a history of neck trauma. Forty-five patients (83%) had a favorable response to injection. Overall, there was no significant change in scalene muscle height for either the injected side (preinjection: 90.0 ± 1.2 mm vs. postinjection: 90.7 ± 1.2; P = 0.12) or the control side (preinjection: 89.3 ± 1.4 mm vs. postinjection: 88.9 ± 1.3 mm; P = 0.83). However, when stratified by patient response, those with a positive response had a larger increase in muscle height for the injected side than for the control side (change in baseline: 0.65 ± 0.58 mm vs. -0.53 ± 0.48 mm; P = 0.05). In contrast, nonresponders had no significant change in scalene height for either the injected or control side (change in baseline: 0.59 ± 1.30 mm vs. 0.37 ± 1.07; P = 1.00). Notably, responders had significantly longer anterior scalene muscles at baseline than nonresponders (92.2 ± 1.1 mm vs. 79.5 ± 2.5; P < 0.001). CONCLUSIONS: LA blocks of the anterior scalene muscle may provide symptomatic relief in patients with neurogenic TOS by increasing muscle height, although the clinical significance of this small change is unclear. Patients who do not have a response to the block tend to have significantly shorter anterior scalene muscle heights than patients who respond, suggesting an anatomic difference in responders versus nonresponders.

A simplified ultrasonography-guided approach for neurotoxin injection into the obliquus capitis inferior muscle in spasmodic torticollis.

The obliquus capitis inferior (OCI) muscle may be crucially involved in generating the tremulous component of spasmodic torticollis. This study was undertaken to evaluate the efficacy of a simplified ultrasonography-guided approach of botulinum neurotoxin injection into the OCI in the management of spasmodic torticollis. Here, a novel off-plane technique of ultrasonography-guided botulinum neurotoxin injection into the OCI is demonstrated on video. We investigated its effect in five patients with tremulous torticollis with only partial response to conventional injection technique not injecting OCI. On ultrasonography the OCI and its neighboring structures (greater occipital nerve, vertebrae C1 and C2) were clearly displayed. Unlike the previously proposed approach with axial OCI imaging and in-plane medio-lateral needle insertion, we applied here an off-plane needle insertion technique. With this, the ultrasonography guidance of needle insertion was easier using the sagittal imaging plane rather than the axial plane. Compared to botulinum neurotoxin injection into more superficial neck muscles only, additional ultrasonography-guided botulinum neurotoxin injection into the OCI led to a higher benefit (self-rated improvement of cervical dystonia, p = 0.026, Mann-Whitney test), especially of the tremulous component (p = 0.007), even though the total botulinum neurotoxin dose was not changed. We conclude that selected patients with tremulous torticollis may benefit from botulinum neurotoxin injection into the OCI.

Anatomy and cervical dystonia : "Dysfunction follows form".

At first glance, cervical dystonia might be an illustration of the well-known proposition "function follows form". Nevertheless, cervical dystonia is a highly non-physiological condition, which cannot be reproduced by healthy subjects and does not respond to the usual physiological rules. "Dysfunction follows form" might be the most accurate aphorism to define cervical dystonia. Taking into account this situation and recent insights, the anatomic approach needs to be adapted to allow a better understanding of semiology and to improve botulinum toxin therapy. In this review dealing with a new approach to cervical dystonia, we develop some practical anatomical concepts concerning the head and neck complex. Knowledge of cervical spine and muscular dysfunctions in cervical dystonia is an essential stage in treating cervical dystonia patients with botulinum toxin.

Insights into the Functional Anatomy Behind the PREEMPT Injection Paradigm: Guidance on Achieving Optimal Outcomes.

OBJECTIVE: To provide clinically relevant insights on the identification of the muscles and techniques involved in the safe and effective use of onabotulinumtoxinA for chronic migraine prophylaxis. BACKGROUND: Although guidance on the use of onabotulinumtoxinA for chronic migraine is available, based on the Phase III Research Evaluating Migraine Prophylaxis Therapy (PREEMPT) clinical program, clinical experience has shown that insufficient understanding of the anatomy and function of the head and neck muscles may lead to undesirable outcomes and suboptimal efficacy. DESIGN/METHODS: Each muscle involved in the standardized PREEMPT injection paradigm is reviewed with a thorough description of each muscle's anatomy (ie, muscle description and location, innervation, vascular supply) and function. Key insights based on clinical experience are also provided to help improve outcomes. RESULTS: The identification of the muscles in the PREEMPT injection paradigm should be based on each patient's unique anatomy and injections should be administered using the advised techniques. A thorough examination of the patient prior to treatment is also critical to determine if any preexisting conditions may increase the risk for unwanted outcomes and appropriate expectations should be communicated. CONCLUSIONS: Thorough knowledge of the functional anatomy of the muscles involved in the standardized PREEMPT injection paradigm is critical to achieve the efficacy and safety observed in clinical trials. In addition, it is important to assess a patient's baseline condition to anticipate the risk for unwanted outcomes that may result from treatment.

The occurrence of lateral shift in cervical dystonia.

Aim of this study is to identify factors contributing the occurrence of neck lateral shift (LS) in patients with cervical dystonia (CD). A retrospective analysis focused on the treatment with botulinum toxin (BTX) was conducted on 38 consecutive idiopathic CD patients comparing subjects with and without LS. The main result was the evidence of a significantly higher BTX inter-side dose difference in patients with LS suggesting that this uncommon phenotype may be an artifact of chronic therapy with BTX.

Relevance of sonography for botulinum toxin treatment of cervical dystonia: an expert statement.

Botulinum neurotoxin A (BoNT A) is the first-line treatment for cervical dystonia. However, although BoNT A has a favorable safety profile and is effective in the majority of patients, in some cases the treatment outcome is disappointing or side effects occur when higher doses are used. It is likely that in such cases either the target muscles were not injected accurately or unintended weakness of non-target muscles occurred. It has been demonstrated in clinical trials for spastic movement disorders that sonography-guided BoNT A injections could improve treatment outcome. As the published evidence for a benefit of sonography-guided BoNT injection in patients with cervical dystonia is scarce, it is the aim of this review to discuss the relevance of sonography in this indication and provide a statement from clinical experts for its use. The clear advantage of sonography-guided injections is non-invasive, real-time visualization of the targeted muscle, thus improving the precision of injections and potentially the treatment outcomes as well as avoiding adverse effects. Other imaging techniques are of limited value due to high costs, radiation exposure or non-availability in clinical routine. In the hands of a trained injector, sonography is a quick and non-invasive imaging technique. Novel treatment concepts of cervical dystonia considering the differential contributions of distinct cranial and cervical muscles can reliably be implemented only by use of imaging-guided injection protocols.

Gallic acid exhibits risks of inducing muscular hemorrhagic liposis and cerebral hemorrhage--its action mechanism and preventive strategy.

Gallic acid (3,4,5-trihydroxybenzoic acid) (GA) occurs in many plants. The adverse effects of GA are seldom cited. GA (6-14 µM) provoked the hemorrhagic liposis of the cervical muscles and intracranial hemorrhage. The cause of these pathological events and the method for prevention are still lacking. Using the chicken embryo model and some selected nutraceutics such as folate, glutathione (GSH), N-acetylcysteine, and vitamin E (Vit E), we carried out this study. Results revealed that the action mechanism of GA involved (i) inducing hypoxia with upregulated gene hif-1α and downregulated ratio vegf-r2/vegf-a, leading to dys-vascularization and myopathy; (ii) impairing cytochrome c oxidase; (iii) stimulating creatine kinase and lactate dehydrogenase release; (iv) eliciting carnitine accumulation and liposis via downregulating gene CPT1; (v) suppressing superoxide dismutase and stimulating NO, H2O2, and malondialdehyde; and (vi) depleting erythrocytic and tissue GSH, resulting in hemorrhage. When both Vit E and GSH were applied to the day 1 chicks, a better alleviation effect was revealed. Conclusively, GA potentially exhibits adverse effect by eliciting hemorrhagic liposis of cervical muscles and cerebral hemorrhage. Supplementation with GSH, Vit E, and N-acetylcysteine is able to ameliorate these adverse effects, warranting the importance of restricting the clinical phytotherapeutic doses of GA and related compounds.

The clinical utility of botulinum toxin injections targeted at the motor endplate zone in cervical dystonia.

BACKGROUND AND PURPOSE: Cervical dystonia (CD) patients usually receive repeated botulinum neurotoxin (BoNT) injections. The aims of this study were to evaluate the feasibility of motor endplate zone (MEZ) detection of relevant cervical muscles in CD patients receiving chronic BoNT treatment and to compare the treatment effect of half-dosed, endplate-targeted injections to standard BoNT injections. METHODS: In study 1, high-density surface electromyography (HD-sEMG) was recorded from the sternocleidomastoid (SCM) and splenius capitis (SC) muscles in 18 CD patients with ongoing BoNT treatment, by which the location of the MEZ was determined. In study 2, nine additional patients with rotational-type CD participated in a treatment effect study where they received either half of their regular BoNT dose through endplate-targeted injections or their normal BoNT dose through standard injections (crossover design). Dystonia severity was recorded before and 4 weeks after each treatment session (Toronto Western Spasmodic Torticollis Rating Scale severity subscore). RESULTS: In the SCM muscle the MEZ was located at the lower border of the superior third part of the muscle, and in the SC muscle at half muscle length. Endplate-targeted, half-dosed BoNT injection resulted in a similar treatment effect to injecting the full dose in the standard technique. CONCLUSIONS: Half-dosed, endplate-targeted BoNT injections lead to a similar treatment effect to the standard BoNT injection protocol. MEZ detection confronts the clinician with some technical challenges, such as the ability of accurate and technically optimal placement of the electrode grid and correct interpretation of the HD-sEMG signal.

Hydrogen peroxide alters sternohyoid muscle function.

Upper airway (UA) dilator muscles are critical for the maintenance of airway patency. Injury or fatigue to this group of muscles, as observed in patients with obstructive sleep apnoea (OSA) and animal models of OSA, may leave the UA susceptible to collapse. Although the mechanisms underlying respiratory muscle dysfunction are not completely understood, there is strong evidence suggesting a link between increased production of reactive oxygen species and altered muscle function. The aim of this study was to examine the effects of H2O2 on rat sternohyoid muscle function in vitro. Sternohyoid contractile and endurance properties were examined at 35 °C under control or hypoxic conditions. Studies were conducted in the presence of varying concentrations of H2O2 (0, 0.01, 0.1 and 1 mM). Muscle function was also examined in the presence of antioxidants [desferoxamine (DFX), catalase] and the reducing agent dithiothreitol (DTT). H2O2 decreased muscle endurance in a concentration-dependent manner. This was partially reversed by catalase, DFX and DTT. Our results suggest that oxidants may contribute to UA respiratory muscle dysfunction with implications for the control of UA patency in vivo.

Chemoradiation to the submental muscles alters hyoid movement during swallowing in a rat model.

Hyolaryngeal dysfunction is a commonly reported swallowing problem after chemoradiation treatment for head and neck cancer. The displacement of the hyolaryngeal complex during swallowing protects the airway and assists in opening the upper esophageal sphincter. Activation of the submental muscles, specifically the mylohyoid and geniohyoid muscles, is thought to facilitate movement of the hyoid. The purpose of this study was to determine if targeted radiation to the submental muscles given concurrently with chemotherapy alters hyolaryngeal displacement 1 mo after treatment. We hypothesized that chemoradiation treatment would result in abnormal patterns of hyoid movement compared with controls. Furthermore, we propose that these changes are associated with alterations in bolus size and discoordination of the jaw during drinking. Eighteen rats underwent either chemoradiation, radiation, or no treatment. Radiation treatment was targeted to submental muscles using a clinical linear accelerator given in 12 fractions of 4 Gy (3 days per week). Cycles of 1 mg/kg of cisplatin were administered concurrently each week of radiation. One month posttreatment, videofluoroscopy swallow studies (VFSS) were performed in self-drinking rats using a fluoroscope customized with a high-speed camera. The hyoid, jaw, and hard palate were tracked during swallowing from VFSS. Hyoid kinematics were analyzed from the start to the end of hyoid movement, and parameters were compared with bolus size and jaw movement. Significant differences in hyoid retraction parameters were found postchemoradiation. Alterations in the trajectory of hyoid motion during swallowing were observed. The findings demonstrate early changes in hyoid motion during swallowing associated with chemoradiation treatment.NEW & NOTEWORTHY Chemoradiation treatment for head and neck cancer can cause functional impairments in swallowing, which can adversely affect quality of life. This study provides new evidence that chemoradiation targeted to the submental muscles provokes early adaptations in hyoid movement during swallowing, which correlate with changes in bolus size. We also demonstrate a method for tracking the hyoid during swallowing in a rat model of chemoradiation injury.

The effects of pressure release, phonophoresis of hydrocortisone, and ultrasound on upper trapezius latent myofascial trigger point.

OBJECTIVE: To compare the effects of pressure release (PR), phonophoresis of hydrocortisone (PhH) 1%, and ultrasonic therapy (UT) in patients with an upper trapezius latent myofascial trigger point (MTP). DESIGN: Repeated-measure design. SETTING: A pain control medical clinic. PARTICIPANTS: Subjects (N=60; mean±SD age, 21.78±1.76y) with a diagnosis of upper trapezius MTP participated in this study. Subjects were randomly divided into 4 groups: PR, PhH, UT, and control (15 in each group). All patients had a latent MTP in the upper trapezius muscle. INTERVENTIONS: PR, PhH, UT. MAIN OUTCOME MEASURES: Subjective pain intensity, pain pressure threshold (PPT), and active cervical lateral flexion range of motion were assessed in 6 sessions. RESULTS: All 3 treatment groups showed decreases in pain and PPT and an increase in cervical lateral flexion range of motion (P<.001) compared with the control group. Both PhH and PR techniques showed more significant therapeutic effects than UT (P<.001). CONCLUSIONS: Our results indicate that all 3 treatments used in this study were effective for treating MTP. According to this study, PhH is suggested as a new method effective for the treatment of MTP.

Somatosensory cortical activation in cervical dystonia and its modulation with botulinum toxin: an fMRI study.

Converging data on focal dystonias suggest a widespread disorder of somatosensory processing. The aims of our study were, first, to assess somatosensory activation patterns in cervical dystonia (CD) beyond the representation of the affected body parts and, second, to search for task-related activation changes induced by botulinum toxin type-A (BoNT-A) therapy. Functional magnetic resonance imaging (MRI) during electrical median nerve stimulation was employed in seven CD patients and nine controls; the examination was repeated 4 weeks after BoNT-A application to dystonic neck muscles. The pretreatment activation map of patients showed activation in the contralateral primary somatosensory cortex, but missing activation in the secondary somatosensory cortex and insula, in contrast to controls and patients after treatment. Clinically significant effect of BoNT-A therapy was associated with a significant increase of BOLD response in the contralateral secondary somatosensory, insular, and inferior parietal cortices. The posttreatment somatosensory maps of patients did not significantly differ from controls. This study has brought evidence of widespread disruption of somatosensory processing in CD and its modification with BoNT-A therapy.

Scalene muscle injections for neurogenic thoracic outlet syndrome: case series.

UNLABELLED: Scalene muscle injections are used to confirm the diagnosis of neurogenic thoracic outlet syndrome and predict the response of patients to surgery. We performed a retrospective study to determine if relief of pain was related to brachial plexus blockade in these patients. METHODS: We reviewed the charts of 12 patients who had anterior and middle scalene muscle injections, for neurogenic thoracic outlet syndrome, between April 2009 and September 2010. The injections were performed under ultrasound guidance wherein 2 to 5 mL of 0.25% bupivacaine was injected into the belly of the anterior and scalene muscles. The following were noted: (1) sites of preprocedure pain; (2) volume injected into each of the anterior and middle scalene muscles; (3) presence of numbness after injection; and (4) presence and duration of pain relief. RESULTS: All 12 patients had relief of their pain. Six of the twelve patients developed numbness, which ranged from blockade of the C4-5, C6-7, and C4-T1 dermatomes. In the patients who developed numbness, there was no relationship between the duration of numbness and the duration of pain relief or the location of numbness and the location of pain relief. CONCLUSIONS: The relief from scalene muscle injections in patients with neurogenic thoracic outlet syndrome is not related to blockade of the brachial plexus.

Anterior and posterior sagittal shift in cervical dystonia: a clinical and electromyographic study, including a new EMG approach of the longus colli muscle.

Anterior and posterior sagittal shift of the head are less common postures in cervical dystonia and, as such, have not been comprehensively studied. In this article, we have detailed both our clinical and electromyography (EMG) findings in 11 patients with prominent dystonic sagittal shift of the head. A new technique of injection of the longus colli, based on a laterocervical approach under EMG guidance, is described. We have detailed the clinical phenotypes of dystonic posterior sagittal shift or "double chin" posture (4 patients) and anterior sagittal shift or "goose neck" posture (7 patients) and proposed specific botulinum toxin (BoNT) treatment protocols for these postures. Seven patients with the goose-neck posture responded well (70%-90% benefit) to BoNT injections. Six patients responded to splenius capitii injections alone, and 1 patient needed, in addition, the injection into both sterno-cleido-mastoid muscles. Four patients with the double-chin posture responded well to BoNT injection (50%-80% benefit). Two patients responded to suprahyoid injection alone, and 2 patients needed, in addition, the injection into the sterno-cleido-mastoid and longus colli muscles. Dysphagia was avoided in all of the double-chin patient group by adjusting our injection technique into the suprahyoid and longus colli muscles. The individualised toxin BoNT protocols have resulted in an improved benefit. The new Longus colli injection technique has allowed for a therapeutic effect of botulinum toxin without causing dysphagia.

Onabotulinum toxin A treatment of cervicogenic headache: a randomised, double-blind, placebo-controlled crossover study.

AIMS: Preliminary reports regarding injections in the neck of onabotulinum toxin A have been positive in cervicogenic headache (CeH). The aim was to perform the first methodologically rigorous trial. METHODS: A randomised, placebo-controlled, patient-, injector- and evaluator-blinded crossover study included 28 adult patients with a long-standing and treatment-resistant CeH. After a baseline period, injections of either onabotulinum toxin A or placebo were given in fixed sites in the neck muscles on the pain side. Second injections were given after ≥8 weeks. Patients were thereafter followed for another 8 weeks. A detailed headache calendar was filled in, and patients were followed with quality-of-life (QoL) questionnaires, algometry and neck mobility measurements. RESULTS: There was no significant difference between verum and placebo in a mixed linear model analysis (p = 0.084) with regard to the primary end-point, reduction of days with moderate to severe headache. Six patients withdrew from the study before the second injections, but an intention-to-treat (ITT) analysis gave a similar result (p = 0.27). There were no significant differences favouring verum in any of the secondary efficacy measures. Side-effects of onabotulinum toxin A were minor and short-lasting. CONCLUSION: Onabotulinum toxin A in neck muscles does not seem to be beneficial in CeH.