Fluoroscopic, EMG-guided injection of botulinum toxin into the longus colli for the treatment of anterocollis

BackgroundAnterocollis is a form of cervical dystonia characterized by forward neck flexion. While botulinum toxin is the treatment of choice for cervical dystonia, patients with anterocollis, who receive injections into the sternocleidomastoid and anterior scalene muscles, represent a disproportionate number of treatment failures. Deep cervical muscles such as the longus colli likely play an important role in neck flexion but are not routinely injected.ObjectiveTo describe a technique for longus colli injection in cases of anterocollis and to report the clinical outcomes of 10 such injections of botulinum toxin.MethodsThree patients were referred for evaluation and treatment of anterocollis. All had previous treatment failures with sternocleidomastoid/anterior scalene injections or no activity noted on needle EMG investigation of these muscles. All patients received injections of botulinum toxin into the longus colli under fluoroscopic and EMG guidance.ResultsAll patients experienced symptomatic improvement (eight of 10 injections). Two patients reported mild dysphagia without serious complications after dose increases in botulinum toxin.ConclusionsIncomplete muscle selection may be one cause of treatment failures in anterocollis. Deep cervical flexors such as the longus colli represent an under-recognized potential target for symptomatic treatment of anterocollis.     

Electromyographic evaluation of cervical dystonia for planning of botulinum toxin therapy

The success of botulinum toxin (BT) injections for treatment of cervical dystonia depends on precise identification of dystonic muscles and on quantification of their dystonic involvement. Conventionally, this is attempted by clinical examination analysing the dystonic head position. In this presentation, a more systematic approach is sought by using an electromyography (EMG)-based evaluation procedure. In 10 consecutive patients with cervical dystonia not previously exposed to BT clinical examination, analysing the dystonic head position was performed to classify patients into four groups with similar dystonic head positions. Additionally, a 2-channel concentric needle EMG was used to measure the amplitudes of dystonic and maximal voluntary activities in sternocleidomastoid (SCM), splenius capitis (SC) and trapezius/semispinalis capitis (T/SS) muscles bilaterally. The ratio between both amplitudes, the dystonia ratio, was used to quantify dystonic muscle involvement. In all patients dystonia ratios could be calculated. In patients with similar head positions, EMG evaluation revealed different qualitative and quantitative dystonic involvement patterns. In six patients, there were discrepancies in identification of dystonic muscles between clinical examination and EMG evaluation. EMG evaluation excluded dystonic involvement in five patients. All excluded muscles were SCM. In one of these patients, additional T/SS involvement was detected by EMG evaluation. In one patient, SC involvement was revealed by EMG evaluation. All dystonic muscle involvement detected by EMG evaluation represented genuine dystonic muscle coactivation rather than compensatory muscle activity. The EMG evaluation presented allows quantitative and qualitative identification of dystonic muscle involvement which cannot be achieved by clinical examination. Both pieces of information may be helpful for optimization of BT therapy.     

Utility of an EMG mapping study in treating cervical dystonia

Intramuscular injections of botulinum toxin are the cornerstone of treatment for cervical dystonia. Controversy exists regarding the necessity for EMG-guided injections. We compared the clinical examination of four movement disorder specialists to an electromyographic (EMG) mapping study. Clinical predictions of individual muscle involvement were only 59% sensitive and 75% specific. Muscle hypertrophy, shoulder elevation, and dominant head vector did not bolster clinical accuracy. An EMG mapping study facilitates identification of dystonic muscles in cervical dystonia, which may enhance botulinum toxin therapy.     

Accuracy of muscle localization without EMG: implications for treatment of limb dystonia

Although botulinum toxin is an effective treatment for focal dystonia, the importance of electromyography (EMG) in identifying muscles and guiding injections is unclear. The authors examined the accuracy of muscle localization in 38 muscles in patients with focal hand dystonia without EMG guidance. Only 37% of needle placement attempts reached the target muscles or muscle fascicles. This study demonstrates that EMG guidance is needed for correct localization of desired muscles.     

Elimination of dysphagia using ultrasound guidance for botulinum toxin injections in cervical dystonia

Introduction: Dysphagia is a common side effect after botulinum toxin injections for cervical dystonia, with an incidence of 10–40%, depending upon the study and dose used. Methods: Our study consisted of 5 preselected women who met criteria for cervical dystonia and subsequent dysphagia after electromyography (EMG)‐guided injections. Injections were performed with ultrasound (US) imaging, and the effects on swallowing were examined. Separately, sternocleidomastoid (SCM) thickness in healthy controls and treated patients was measured. Results: There were 34 episodes of dysphagia over 98 injection sessions using EMG guidance for a cumulative rate of 34.7%. Using US plus EMG guidance, there was 0% dysphagia across 27 injection sessions. SCM thickness was <1.1 cm. Conclusion: US combined with EMG guidance eliminated recurrent dysphagia after botulinum toxin treatment, possibly by keeping the injectate within the SCM. Muscle Nerve 46: 535–539, 2012     

Remote effects of chronic botulinum toxin treatment: electrophysiologic results Do not indicate subclinical remodelling of noninjected muscles

This study investigates the remote effects of botulinum toxin injections by examining the motor unit architecture of noninjected distant muscles. In 21 dystonia patients treated with botulinum toxin (n = 11, mean cumulative dose = 815 mU; n = 10, mean cumulative dose = 7,207 mU) and 10 control individuals, a blinded single-fiber electromyography of the vastus lateralis muscle was performed. The main outcome measure was fiber density (FD), thus measuring the effect of different cumulative doses on remote reinnervation. FD was normal in all patients treated with botulinum toxin. FD did not differ between the three groups studied. No relationship was found between FD and cumulative dose. Therefore, in this specific patient population, muscles remote to the site of injection showed no FD change months after the injection. We conclude that there was no evidence of remote reinnervation and remodelling of motor units with cumulative chemodenervation.     

Change in the pattern of cervical dystonia might be the cause of benefit loss during botulinum toxin treatment

The muscular patterns of cervical dystonia were identified by polymyographic recordings in 76 patients before botulinum toxin treatment. The leading muscles were considered to be those which started dystonic movement and which showed constant and maximal activity during all dystonic movements. The dystonic muscles were repeatedly treated by local Injections of botulinum toxin. Sixteen patients showed (after repeated injections) loss of the benefit of local applications of botulinum toxin after various periods of time. Repeated polymyographic recordings were performed in these patients during the loss of the benefit of injected botulinum toxin. In four patients repeated polymyographic recordings showed an Identical pattern of cervical dystonia, but the activity of previously injected muscles was apparently decreased. In 12 patients only minimum or no activity was recorded in muscles which had previously been treated with botulinum toxin, but the pattern of cervical dystonia was changed. Different patterns of cervical dystonia with different leading muscles, but with identical directions of head deviation, were observed in six patients. In another six patients, the head deviation direction was to the opposite side and was accompanied by a change of the leading muscle and a change of the muscular pattern of dystonia. These results suggest either that dystonic activity from the cerebral generator changes to new effectors during the peripheral blockade of primary dystonic muscles, or that a change of generators at different levels of the CNS occurs. It may be neccessary to carry out repeated polymyographic recordings throughout the period of loss of benefit of previously successful local botulinum toxin injections.     

肌张力障碍的肌电图表现

目的:采用定量和定性相结合的肌电图方法对肌张力障碍(dystonia)病人进行测定,观察肌电活动情况,评价肌电图在捡出异常肌肉中的价值。方法:观察肌张力障碍患者48例,正常健康人群12例分别在静息时、小收缩时和大收缩时的肌电活动。结果:肌张力障碍患者在静息时有不规则的群化电位出现,或活动后运动单位持续存在,是肌肉痉挛的特异性改变;大收缩时募集相不完全其转折数明显降低。结论:所有肌电图的表现提示上运动神经元-脊髓、脑干或大脑皮层的异常放电,对病人进行肌电图检查有助于提高受损肌肉的检出率。     

Turns amplitude analysis of the orbicularis oculi and oris muscles.

OBJECTIVE: The aim of the study was to determine whether 'clouds' from turns amplitude analysis obtained from the orbicularis oculi and oris muscles without force monitoring can be used to differentiate pathological processes affecting the face. METHODS: The interference pattern from orbicularis oculi and orbicularis oris was studied using a concentric needle electrode. Data-points from 20 normal subjects were plotted on a logarithmic scale of mean amplitude between turns versus turns/second, from which linear regression analysis defined the 95% confidence intervals. This enabled us to draw the boundaries of the normal cloud on a linear plot. Data-points from the interference pattern in two pathological cohorts, of 6 patients receiving botulinum toxin injections (representing a neurogenic model), and 6 patients with a muscle dystrophy (representing a myopathic model) were plotted against the normal cloud. These findings were compared and correlated with the mean durations obtained on motor unit action potential analysis from these same two facial muscles. RESULTS: The majority of patients receiving botulinum toxin injections into their facial muscles showed a pattern of high amplitude with low turns/s, or low amplitude with a low-to-normal range of turns/s in both facial muscles. These findings were associated with high-duration motor unit action potentials in most cases. In the myopathic group of patients 66% showed a pattern of low amplitude with low-to-normal range of turns/s in O oculi and O oris. This correlated with short-duration motor unit action potentials in both facial muscles. CONCLUSIONS: We have demonstrated that turns amplitude analysis without force monitoring can be used to study the interference pattern from facial muscles and can be applied to differentiate primary neurogenic from myopathic pathological processes. SIGNIFICANCE: Turns amplitude analysis without force monitoring in the facial muscles can be used as an effective and practical method of interference pattern analysis to complement findings from conventional motor unit action potential analysis.     

Spasmodic torticollis: experience of 5 years with botulinum toxin treatment]

64 cases with spasmodic torticollis were observed during 5 years and treated with botulinum toxin (BTX). BTX was injected into dystonic muscles mostly into sternocleidomastoid then--trapezius, and splenius capitis muscle. Improvement (excellent, good and fair) was achieved in 40 patients (62%). Lack of information about 6 patient (9%). Injections were repeated every 3-4 months and in several cases even 1-2 during the year. After several injections atrophy and denervation potentials in EMG were observed in the majority of injected muscles. Neurotic syndromes coexisting with dystonia had worsening influence on therapeutic effects. Adverse events were observed in 5 cases. Treatment with BTX is very simple, easy, harmless and can be administered in outpatients.     

Cervical dystonia: Improved treatment response to botulinum toxin after referral to a tertiary centre and the use of polymyography

RationaleCervical dystonia is the most common form of (primary) dystonia. The first line of treatment for cervical dystonia is intramuscular injections with botulinum toxin. To optimise the response to botulinum toxin proper muscles selection is required. Pre-treatment polymyographic EMG in addition to clinical evaluation is hypothesised to be a good tool to improve muscle selection and treatment outcome.ObjectiveTo determine the efficacy of botulinum toxin treatment after adjacent polymyographic EMG in cervical dystonia patients referred to our tertiary referral centre with an unsatisfactory response to botulinum toxin treatment elsewhere.MethodsWe performed a retrospective analysis of 40 consecutive second opinion cervical dystonia patients. Standard polymyographic EMG was performed before treatment. We retrieved the Tsui scores and subjective evaluations from the first visit, after 12 weeks and after one year of treatment. In addition, we assessed the final outcome of treatment in our centre based on the records and asked the patients for their personal opinion about the effect of referral to our centre on their treatment response.ResultsAfter one year of treatment there was a significant improvement on both the Tsui scores (p < 0.01) and the subjective treatment evaluation (p < 0.001.) On their last visit 60% of the patients still continued treatment with a reasonable to good response.ConclusionA substantial amount of CD patients with an unsatisfactory response to botulinum toxin improved after polymyography and subsequent treatment with botulinum toxin in a tertiary referral centre.     

Neurophysiological observations on the effects of botulinum toxin treatment in patients with dystonic blepharospasm.

Botulinum toxin treatment improves dystonic blepharospasm by inducing transient paresis of the orbicularis oculi muscle. It is not known if it also reduces the enhanced brainstem neuronal excitability found in this disorder. We have performed conventional electromyography (EMG) and blink reflex excitability studies on fifteen patients with blepharospasm before and after botulinum toxin treatment. Denervation signs were found with needle EMG in all treated muscles. Amplitude of the facial compound muscle action potential (CMAP) and R1 response was reduced after botulinum toxin injections. In blink reflex excitability studies, the recovery of R2 response was enhanced after treatment even when patients were tested at the time of maximal benefit from botulinum toxin injections. The results suggest that there is little influence of botulinum toxin treatment upon the enhanced excitability of brainstem interneurons in patients with blepharospasm.     

Polymyography combined with time-locked video recording (video EMG) for presurgical assessment of patients with cervical dystonia

We assessed 26 patients with cervical dystonia, in whom botulinum toxin (BT) injections had failed, before selective peripheral denervation. We decided to base the decision which muscle should be denervated on both clinical information and EMG data and focussed on the following features: activity at onset or during 'dystonic spasms' (according to the concept of the 'leading' dystonic muscle), paradoxical activity during voluntary head movements causing restriction of head movements opposite the side of head turn or tilt and activity when symptoms deteriorated during walking. To identify these muscles we developed a new recording system that integrates simultaneous video-taping and polymyography (video EMG) by means of a digital counter, driven by the recording software (resolution 0.1 s), that was fixed in view of the video camera. This system time-locked clinical signs with relevant EMG activity thus allowing demonstration of the above features. These were found in 68% of dystonic muscles with each of them being present in approximately 40%. Video EMG allows an integrated approach to identify overactive neck muscles in patients with cervical dystonia taking into account both relevant clinical findings and EMG data.     

Treatment of spasmodic torticollis with local injections of botulinum toxin

Summary Thirty-seven patients with spasmodic torticollis (cervical dystonia) who received repeated local injections of botulinum toxin have been followed up for a mean period of 12.3 (10–29) months, during which time 138 treatment sessions were performed. Mean doses per muscle averaged 320 mouse units (mu; range 160–1000 mu botulinum toxin A prepared by CAMR, Porton Down, UK). Eighty-six per cent of patients experienced significant improvement of posture and 84% of those with pain had relief following the first injection. Muscular patterns of recurrent torticollis were relatively constant and in most patients efficacy was maintained with subsequent injections, while 15% of all follow-up sessions failed. Only 2 of 37 patients were consistent non-responders; 22% and 10% of all sessions were complicated by transient dysphagia and weakness of neck muscles, respectively. It is concluded that local botulinum toxin injections can be a safe and efficaceous long-term treatment of spasmodic torticollis and that optimal doses should be between 200 and 400 mu/muscle.     

Muscle activity changes in spasmodic torticollis after botulinum toxin treatment

We assessed electromyographic (EMG) activity in neck muscles before and after botulinum toxin injections in 28 patients with spasmodic torticollis (ST) to investigate possible changes in muscle activation after treatment. A six-channel EMG with surface electrodes was used to record activity of sternocleiodomastoid, trapezius and splenius capitis bilaterally. Objective benefit (>25% reduction in Tsui's score) occurred in 22 patients (78%). Of the 168 muscles studied before botulinum toxin injections, 90 presented EMG activity. Sixty-eight of these muscles were injected and a decrease in EMG activity occurred in 44 (65%) of them. A decrease in EMG activity was also detected in 15 (68%) of those which were not injected. On the other hand, 70 of the 78 muscles without pre-botulinum toxin EMG activity were not injected. However, after treatment, EMG activity increased in 37 (52%) of these muscles. These changes involved 18 patients and occurred without concomitant change in the main direction of head deviation despite the improvement observed in most cases. These results suggest that in ST head turning results from an abnormal central motor program which results in non-specific neck muscle activation.     

Botulinum toxin injections reduce associative plasticity in patients with primary dystonia

Botulinum toxin injections ameliorate dystonic symptoms by blocking the neuromuscular junction and weakening dystonic contractions. We asked if botulinum toxin injections in dystonia patients might also affect the integrity of sensorimotor cortical plasticity, one of the key pathophysiological features of dystonia. We applied a paired associative stimulation protocol, known to induce long‐term potentiation–like changes in the primary motor cortex hand area to 12 patients with cervical dystonia before and 1 and 3 months after botulinum toxin injections to the neck muscles. Primary motor cortex excitability was probed by measuring transcranial magnetic stimulation‐evoked motor evoked potentials before and after paired associative stimulation. We also measured the input–output curve, short‐interval intracortical inhibition, intracortical facilitation, short afferent inhibition, and long afferent inhibition in hand muscles and the clinical severity of dystonia. Before botulinum toxin injections, paired associative stimulation significantly facilitated motor evoked potentials in hand muscles. One month after injections, this effect was abolished, with partial recovery after 3 months. There were significant positive correlations between the facilitation produced by paired associative stimulation and (1) the time elapsed since botulinum toxin injections and (2) the clinical dystonia score. One effect of botulinum toxin injection treatment is to modulate afferent input from the neck. We propose that subsequent reorganization of the motor cortex representation of hand muscles may explain the effect of botulinum toxin on motor cortical plasticity. © The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.     

Electromyographic guidance of botulinum toxin treatment in cervical dystonia

We report the results of electromyographic (EMG) guidance in the treatment of cervical dystonia with botulinum toxin. Eight-four patients received a total of 225 injection sessions. Overall there was moderate objective improvement in 78.7%. The mean dose of toxin was 269 +/- 39 mouse lethal units and the mean duration of maximum effect was 107 +/- 49 days. Complications included excessive neck weakness in 16.0% and dysphagia in 11.1% of the injection sessions. We conclude that EMG guidance is a safe and effective method of administering botulinum toxin in the treatment of cervical dystonia.     

Reduced jaw opening from paradoxical activity of mandibular elevator muscles treated with botulinum toxin

The aim of the study was the effect of injections with botulinum toxin A (BTX-A) on reduced jaw opening, caused by paradoxical, antagonistic activity of jaw elevator muscles after brain stem lesions. The study included a male (51 years) and a female (69 years) patient. Subjective assessment, clinical recordings, muscle blocks and electromyography (EMG) were used to diagnose paradoxical activity, and to plan, guide and evaluate the treatment. The paradoxical innervation pattern was unilateral in the male and bilateral in the female. The paradoxical activity during jaw opening amounted to 24-109% of the level during maximum biting, and bursts of paradoxical activity were also present during chewing. EMG-guided blocks and later BTX-A injections of the affected muscles increased the opening by 9-23 mm from pre-treatment values of 15-18 mm, and normalized chewing. The study proved BTX-A to be an effective treatment for reduced jaw opening caused by paradoxical activity. Treatment was optimized by EMG evaluation of the current activity of the jaw elevator muscles, permitting individual treatment plans with longer intervals between BTX-A injections and lower doses than with conventional treatment for oromandibular dystonia. Thus the treatment only had to be repeated one to two times per year to maintain acceptable jaw mobility.     

Treatment of cervical dystonia hand spasms and laryngeal dystonia with botulinum toxin

Summary One hundred and twenty-six patients with different forms of focal dystonia (89 with cervical dystonia, 12 with hand cramps and 25 with laryngeal dystonia) were treated with localised injections of botulinum toxin. Mean doses per muscle were 200 mouse units (m.u.) for treating cervical dystonia, 40–120 m.u. for forearm muscles in writers' cramp and 3.7 m. u. for the thyroarytenoid muscle in laryngeal dystonia. Responder rates have been above 80% in all patient groups and beneficial effects could be reproduced over follow-up periods of up to 4 years. The commonest side-effects were dysphagia after treatment of spasmodic torticollis, weakness of neighbouring muscles after injections for hand cramps and breathiness and hypophonia following laryngeal injections. All these were transient and generally well tolerated. It is concluded that botulinum toxin injections are a safe and effective treatment in all three types of focal dystonia.     

Laryngeal dystonia--personal experience with botulin toxin treatment

Laryngeal dystonia is a focal dystonia occurring more often than it is diagnosed. Adductor type dystonia was described in 5 patients. In 3 cases it manifested itself as blepharospasm, which later developed into Meige's syndrome. The patients were treated with botulinum toxin A injections under EMG control administering 10 i.m. into laryngeal muscles on both sides with good and very good results. There were no serious side effects.