Clinical failure of botulinum toxin A in movement disorders

ObjectiveBotulinum toxin (BTX) injections have been used extensively in medicine; however, little is known about the factors predicting the loss of effectiveness of botulin toxin.MethodsUsing a clinical database, we identified 401 subjects who had been treated for movement disorders from 1998 through 2010 with onabotulinumtoxin A (BTX A) or who switched from BTX A to rimabotulinumtoxin B (BTX B). We compared patients who switched from type A to type B with patients using type A only with regard to number of visits, total number of injections, number of initial and final sites, number of initial units used, and duration of treatments.ResultsWe observed that patients who switched from BTX A to B had a significantly higher number of initial injection sites than patients with BTX A only (BTX A to B median = 8.5; BTX A median = 6; p for difference = 0.006), had a higher number of final sites (BTX A to B median = 9 BTX A median = 7; p = 0.01), and were also more likely to have multiple reasons for injection (BTX A to B = 25.0%; botulin toxin A = 5.3%; p = 0.01). We did not find significant differences between groups based on the other variables.ConclusionsOur findings suggest that higher number of sites rather than higher number of units or years of treatment are associated with the loss of effectiveness to BTX A. It is possible that the loss of effectiveness to the BTX is more strongly elicited when the injections are widely diffuse.     

Comparison of efficacy and immunogenicity of original versus current botulinum toxin in cervical dystonia

The authors compared 130 patients treated for cervical dystonia with original botulinum toxin (BTX) type A (Botox; Allergan, Inc., Irvine, CA), 42 of whom were exposed only to the original BTX type A used before 1998 (25 ng protein/100 units), and 119 treated only with the current BTX type A (5 ng of protein/100 units). Blocking antibodies were detected in 4 of 42 (9.5%) patients treated only with original BTX type A but in none of the 119 patients treated exclusively with current BTX type A (p < 0.004). The current preparation decreased the risk of antibody formation by a factor of six. The authors conclude that the low risk of antibody formation after current BTX type A treatment is related to lower protein load.     

Sudomotor testing discriminates between subjects with and without antibodies against botulinum toxin A--a preliminary observation.

With an increasing number of patients being treated with botulinum toxin A (BTX A), the incidence of neutralizing anti-BTX antibodies (ABA) is rising. Because BTX A is known to inhibit sweating, sudometry seems to be a promising tool to test the efficacy of BTX A. We injected BTX A subcutaneously in normal control subjects and four patients with spasmodic torticollis, two responders and two nonresponders with proven ABA. Sweating was visualized using iodine starch staining and quantified used capacitance hygrometry. BTX A inhibited sweating completely at the injection site in both control subjects and all responders without evidence for ABA. However, continued sweating was recorded when the nonresponders with proven ABA were tested. We conclude that sudomotor testing is able to discriminate between subjects with and without clinically important ABA.     

Effects of botulinum toxin type A on non‐injected bi‐articular muscle include a narrower length range of force exertion and increased passive force

Introduction: The goal of this study was to test the hypothesis that botulinum toxin type A (BTX‐A) injection in rat tibialis anterior (TA) muscle affects the mechanics of its bi‐articular synergist, both actively and passively. Methods: Two groups of Wistar rats were tested: control (no BTX‐A) and BTX (0.1 U of BTX‐A) animals were injected exclusively to the mid‐belly of TA. Extensor digitorum longus (EDL) muscle isometric forces were measured after proximal and distal lengthening. Results: Five days after injection, BTX‐A administration changed EDL mechanics: (1) active forces decreased (proximal muscle length dependently); (2) length range of active force exertion decreased both proximally and distally; and (3) passive muscle forces increased. Conclusions: Effects of BTX‐A appear to not be limited to decreased active muscle tone, but may cause also a narrower active range of movement and increased passive resistance. Through spread of BTX‐A to a bi‐articular muscle, such effects are plausible for both joints spanned. Muscle Nerve 49 : 866–878, 2014     

Evidence-based medicine in botulinum toxin therapy for cervical dystonia

Early controlled studies of botulinum toxin (BTX) in cervical dystonia were unblinded and indicated that BTX injections are more successful than medication. In this article, the use of botulinum toxin (BTX) in cervical dystonia is reviewed according to evidence-based medicine. To document the efficacy of BTX, there have been a number of prospective, placebo-controlled studies of the use of BTX in cervical dystonia. Most were double-blind, some included videotapes to provide blinded objective assessments. The more recent studies of BTX in cervical dystonia focused on particular issues such as utility of EMG guidance, comparison to anticholinergic treatment, BTX serotype B in BTX type A resistant and non-resistant patients and different dosages. Despite the wealth of data generated with prospective placebo-controlled studies on the effectiveness of BTX in cervical dystonia, there is uncertainty on which outcome measures to use to express the efficacy of treatments for cervical dystonia. Disease specific instruments to measure quality of life in cervical dystonia have not been used so far. Data on the use of BTX for cervical dystonia have long been restricted to small series of patients reflecting exclusively the experience of individual specialized centers.

     

Evidence-based medicine in botulinum toxin therapy for cervical dystonia

Early controlled studies of botulinum toxin (BTX) in cervical dystonia were unblinded and indicated that BTX injections are more successful than medication. In this article, the use of botulinum toxin (BTX) in cervical dystonia is reviewed according to evidence-based medicine. To document the efficacy of BTX, there have been a number of prospective, placebo-controlled studies of the use of BTX in cervical dystonia. Most were double-blind, some included videotapes to provide blinded objective assessments. The more recent studies of BTX in cervical dystonia focused on particular issues such as utility of EMG guidance, comparison to anti-cholinergic treatment, BTX serotype B in BTX type A resistant and non-resistant patients and different dosages. Despite the wealth of data generated with prospective placebo-controlled studies on the effectiveness of BTX in cervical dystonia, there is uncertainty on which outcome measures to use to express the efficacy of treatments for cervical dystonia. Disease specific instruments to measure quality of life in cervical dystonia have not been used so far. Data on the use of BTX for cervical dystonia have long been restricted to small series of patients reflecting exclusively the experience of individual specialized centers.     

Intact muscle compartment exposed to botulinum toxin type a shows compromised intermuscular mechanical interaction

Introduction: We tested the hypothesis that BTX‐A diminishes epimuscular myofascial force transmission (EMFT) within an intact muscle compartment. Methods: The tibialis anterior (TA) and extensor hallucis longus (EHL) muscles were kept at constant length, whereas the position of the extensor digitorum longus (EDL) muscle was changed exclusively. Two groups of Wistar rats were tested: a control group (no BTX‐A injected) and a BTX group (0.1 unit of BTX‐A injected into the mid‐belly of TA). Results: In controls, distally altered EDL position affected EDL distal and proximal forces and proximodistal force differences, indicating substantial EMFT. In the BTX group, EDL forces measured at the most proximal position did not change significantly with altered muscle position, and EDL proximodistal force differences became minimized. Conclusions: Use of BTX‐A diminishes EMFT. It may be relevant clinically that BTX‐A compromises intermuscular mechanical interaction, as recent studies have shown that such an interaction plays a role in the abnormal mechanics of spastic muscle. Muscle Nerve 51 : 106–116, 2015     

Volume matters: The influence of different botulinum toxin‐A dilutions for sialorrhea in amyotrophic lateral sclerosis

Introduction: We aimed to determine the effect of different botulinum toxin‐A (BTX‐A) dilutions on the treatment efficacy and side effects for amyotrophic lateral sclerosis (ALS) related sialorrhea. Methods: Ten patients were enrolled in the study. BTX‐A dilution for Group A was 100 U in 1 ml of saline, whereas the dilution for Group B was 100 U in 2 ml of saline. Both groups received 20 U of BTX‐A in each parotid gland, and assessments were made by means of the Drooling Impact Scale, items 1 and 3 of the ALS functional rating scale, and visual analog scales for drooling and swallowing function. Results: Although both groups exhibited a similar improvement in drooling, Group B had a mild but significant deterioration in bulbar function that was not evident in Group A. Conclusions: These results suggest that BTX‐A has a safer profile when reconstituted with 1 ml instead of 2 ml of saline. Muscle Nerve, 2013     

A randomised, double-blind, dose-ranging study to evaluate efficacy and safety of three doses of botulinum toxin type A (Botox) for the treatment of spastic foot

Abstract Botulinum toxin A (BTX) injections have been used successfully in the treatment of post-stroke foot spasticity, but the optimal dose-response relationship for selected muscles has yet to be established. The aim of this study was to outline beneficial and unwanted effects of three different doses of BTX in the treatment of spastic foot. In this randomised, double-blind, dose-ranging study, 45 spastic feet were randomly allocated to one of three groups, each of which was treated with a different dosage of BTX. The doses were decided on the basis of suggestions in the literature. Outcome measures (Modified Ashworth Scale, Medical Research Council Scale, gait assessment, presence of Achilles tendon clonus, Visual Analogue Scales for Gait Function and Pain, Adverse Effects scale) were applied at baseline, 4 weeks and 4 months after treatment. All the groups showed significant scales scores improvements after treatment with BTX. Group II (mean BTX total dose: 322 U) and Group III (mean BTX total dose: 540 U) showed a greater and more prolonged response than Group I (mean BTX total dose: 167 U). Group III showed the highest rate of adverse effects 4 weeks post-treatment. BTX injections constitute a useful and safe method of improving post-stroke foot spasticity, associated pain, gait speed and function. In particular, the medium BTX dosages (320 UI spread over 2–5 muscles) were found to be both safe and effective in producing long-lasting improvement of spastic foot dysfunction.     

Evidence-based approach of the use of Botulinum toxin type A (BTX) in cerebral palsy

A systematic review with the Sachett model of evidence-based medicine of the use of Botulinum toxin type A (BTX) for intervention in children with Cerebral Palsy (CP) is highlighted. Currently, the evidence showed that BTX is useful for treating pes equinus due to spasticity of the gastrocnemius-soleus muscles. However, careful patient selection and goals of treatment have to be addressed. More multi-centre clinical trials with standardized protocols are needed before widespread recommendation of the use of BTX in treating spasticity in CP can be made.     

Biomechanical transformation of the gastroc-soleus muscle with botulinum toxin A in children with cerebral palsy

Objective measures (kinematics and kinetics) were used to study prospectively the effects of botulinum toxin A (BTX/A) on the gastro-soleus muscle in ambulant children with cerebral palsy. In this prospective before and after trial, 15 children with diplegia and 10 children with hemiplegia were studied (mean age 5 years 7 months, range 4 years to 9 years). A range of standardized clinical measures was undertaken but the emphasis for this report is on the three-dimensional gait analysis (3DGA) results. All children showed improvements in sagittal ankle kinematics, as has been previously reported. Two new measures of ankle kinetics were devised: ankle moment quotient (AMQ), and ankle power quotient (APQ). Before intervention, ankle moments were characterized by a 'double bump' ankle moment. A typical abnormal baseline ankle-power curve was triphasic with an initial trough of absorption followed by abnormal mid-stance power generation, instead of the usual A1 pattern, and reduced terminal stance power generation (A2). Three weeks after treatment with BTX/A alone there was a statistically significant improvement of AMQ and APQ; some patients required potentiation of BTX/A with a short period of serial casts. Both groups (BTX/A alone and BTX/A plus casting) continued to show improvement in ankle kinetics from baseline after 12 and 24 weeks. This is the first study to demonstrate improvements in the typical abnormal ankle kinetics which we believe provides evidence of the 'biomechanical transformation of muscle'.     

Botulinum toxin A treatment for primary hemifacial spasm: a 10-year multicenter study

BACKGROUND: Botulinum toxin A (BTX) is the currently preferred symptomatic treatment for primary hemifacial spasm (HFS), but its long-term efficacy and safety are not known. OBJECTIVE: To assess the long-term effectiveness and safety of BTX in the treatment of primary HFS. DESIGN: Retrospective review of medical records of the 1st and 10th years of treatment. SETTING: Outpatient clinics of 4 Italian university centers in the Italian Movement Disorders Study Group. PARTICIPANTS: A series of 65 patients with primary HFS who had received BTX injections regularly for at least 10 years. MAIN OUTCOME MEASURES: Mean duration of improvement and quality of the effect induced by the preceding treatment (measured using a patient self-evaluation scale) and occurrence and duration of adverse effects in the 1st and 10th years of treatment. RESULTS: Using a mean BTX dose per treatment session similar to that used by others, we obtained a 95% response rate and an overall mean duration of improvement of 12.6 weeks during year 1. The effectiveness of BTX in relieving the symptoms of primary HFS, as measured by the response rate and average duration of improvement, remained unchanged in the 1st and 10th years. Patients needed statistically similar BTX doses in the 1st and 10th years. The rate of local adverse effects (including upper lid ptosis, facial weakness, and diplopia) diminished significantly in the 10th year of treatment. CONCLUSION: Treatment with BTX effectively induces sustained relief from symptoms of HFS in the long term, with only minimal and transient adverse reactions.     

Long-term botulinum toxin treatment increases employment rate in patients with cervical dystonia.

We examined the impact of cervical dystonia (CD) and long-term botulinum toxin (BTX) treatment on employment status. Data on employment status at onset of CD, at initiation of BTX treatment, and at evaluation of long-term treatment were obtained from 62 CD patients aged 31-66 years (median, 53 years; 61% females) who had been treated for a median of 5 years (range, 1.5-10 years). The employment rate fell from 84% at the onset of CD to 47% before initiation of BTX treatment. With long-term BTX treatment, 72% of those who worked at the initiation of treatment stayed employed, and 67% of those on sick leave returned to work. A younger age and a higher level of education increased the probability of being employed and avoiding disability benefits. Among those who were younger than 55 years at evaluation of BTX treatment (n = 40), the employment rate increased from 47% to 65% with treatment, and among the male patients, it reached the level of the general population (86%). About half of the 34% who received disability benefits did so already before the BTX treatment was initiated.     

Botulinum toxin A in patients with oromandibular dystonia: long-term follow-up

OBJECTIVE: To study the safety and efficacy of botulinum toxin A (BTX) in patients with oromandibular dystonia (OMD) and to compare the treatment results of the various subtypes of OMD. BACKGROUND: OMD is one of the most challenging forms of dystonia to treat. Pharmacologic therapies are generally not effective, and there are no surgical alternatives. METHODS: Of 202 patients diagnosed clinically to have OMD in a movement disorders clinic over a period of 10 years, 162 patients satisfied the study inclusion criteria. The masseters and submentalis complex were the only two muscle groups injected with BTX in this group of patients. RESULTS: The mean age was 57.9+/-15.3 years and the mean follow-up period was 4.4+/-3.8 years. More than half the patients had jaw-closing (JC) dystonia. A total of 2,529 BTX treatments were administered into the masseter muscles, submentalis complex, or both during a total of 1,213 treatment visits. The mean doses of BTX (per side) were 54.2+/-15.2 U for the masseters and 28.6+/-16.7 U for the submentalis complex. The mean total duration of response was 16.4+/-7.1 weeks. The mean global effect of BTX was 3.1+/-1.0 (range, 0 to 4, where 4 equals the complete abolition of the dystonia), with the JC dystonia patients responding best. Fifty-one patients (31.5%) reported adverse effects with BTX in at least one visit. Complications such as dysphagia and dysarthria were reported in 135 (11.1%) of all treatment visits. CONCLUSIONS: BTX is a safe and effective long-term treatment for OMD. JC dystonia responds better than jaw-opening or mixed dystonias, and the treatment of the latter types of OMD are more likely associated with dysphagia and dysarthria. Jaw-opening dystonia can be treated successfully by injecting the submentalis complex.     

Botulinum toxin and neuromotor rehabilitation: An integrated approach to idiopathic cervical dystonia.

Currently, the best treatment option for idiopathic cervical dystonia (ICD) is injection of botulinum toxin (BTX) into the affected muscles, whereas rehabilitative approaches have given disappointing results. We evaluated whether the association of an ad hoc rehabilitative program may improve the clinical efficacy of BTX treatment in a single-center, cross-over, controlled study. Forty patients with ICD were randomly assigned to two different treatment groups: (1) BTX type A (BTX-A) plus a specific program of physical therapy (BTX-PT) or (2) BTX-A alone (BTX-0). Patients in the BTX-PT group showed a longer duration of the clinical benefit (118.8 vs. 99.1 days) and needed a lower dose of BTX at reinjection (284.5 vs. 325.5 units). In addition, they showed more marked reductions in their disability in activities of daily living (-9.7 vs. -4.85 points) and subjective pain (-13.35 vs. 6.95 points) scores. Association of BTX-A therapy with a specific program of physical therapy may improve ICD treatment outcome.     

A randomised, double blind, placebo controlled trial of botulinum toxin in the treatment of spastic foot in hemiparetic patients.

OBJECTIVE: To confirm the apparent effectiveness of botulinum toxin (BTX) in hemiparetic patients with ankle plantar flexors and foot invertor spasticity. METHODS: Twenty three hemiparetic patients with spasticity of the ankle plantar flexors and foot invertors were included in a randomised double blind, placebo controlled study with BTX. Patients were examined on days 0, 30, 90, and 120 and received one injection of BTX and one of placebo in a random order at day 0 and day 90. RESULTS: Patients reported a clear subjective improvement in foot spasticity after BTX (P = 0.0014) but not after placebo. Significant changes were noted in Ashworth scale values for ankle extensors (P < 0.0001) and invertors (P = 0.0002), and for active ankle dorsiflexion (P = 0.0001). Gait velocity was slightly but not significantly (P = 0.0731) improved after BTX injections. The severity of spasticity did not modify treatment efficacy, but BTX was less effective in patients with longer duration of spasticity (P = 0.0081). CONCLUSION: The efficacy of BTX injections in the treatment of spastic foot suggests that BTX may be particularly useful during the first year after a stroke.     

Botulinum toxin use in neuro-rehabilitation to treat obstetrical plexus palsy and sialorrhea following neurological diseases: A review

In neuro-rehabilitation, botulinum toxin (BTX) as adjunct to other interventions can result in a useful therapeutic tool treating disabled people. Other than spasticity, numerous motor and non motor disorders can complicate clinical course and hamper rehabilitative process of neurological impaired patients. A review of BTX use in treating muscular imbalance of children with obstetrical brachial plexus palsy and in reducing sialorrhea following neurological diseases including amyotrophic lateral sclerosis (ASL), Parkinson disease and cerebral palsy (CP) is provided. Clinicians have to face unique and difficult to treat clinical conditions such as ulcers, sores and abnormal posture and movement disorders due to neurological affections. BTX effectiveness in treating some of these conditions is also provided. Since, neurologically disabled subjects can show complex dysfunction, prior to initiating BTX therapy, specific functional limitations, goals and expected outcomes of treatment should be evaluated and discussed with family and caregivers.     

Sweet's syndrome associated with encephalitis

Botulinum toxin (BTX) has been used successfully to treat various movement disorders, and is increasingly used for many other medical conditions. Sialorrhoea is a disabling symptom in many neurological patients including those with Parkinson's disease, stroke and amyotrophic lateral sclerosis (ALS). BTX has recently been shown to be effective for treating sialorrhoea.

We report an ALS patient who developed recurrent jaw dislocation following BTX treatment for sialorrhoea to highlight the observation that intraparotid BTX may be complicated by jaw dislocations in some at-risk ALS patients. Clinicians using BTX to treat sialorrhoea in ALS need to be aware of this potentially serious complication.     

Distant effects of locally injected botulinum toxin: a double-blind study of single fiber EMG changes

We used single fiber electromyography (SFEMG) to study 42 patients who had enrolled in a double-blind, placebo-controlled trial undertaken to assess the efficacy of botulinum toxin (BTX) injection of neck muscles to treat torticollis. SFEMG in a limb muscle was performed before treatment, 2, and 12 weeks after injection of placebo or BTX. Before treatment, the mean jitter was 26.8 microsec in patients who were to receive BTX, and 25.7 microsec in the placebo group. Two weeks after injection, mean jitter in the group receiving BTX was 43.6 microsec. In the placebo group, it was 26.5 microsec (P = less than .05). Twelve weeks after injection, mean jitter in the BTX group was 35.5; for the placebo group it was 24.5. Fiber density did not change in any patient during the study. There were no remote clinical effects of BTX. Injection of BTX into muscles affected with focal dystonia is a promising and safe treatment, but there are subclinical effects on uninjected muscles.     

Double-blind, placebo-controlled study to evaluate the efficacy and safety of botulinum toxin type A in the treatment of drooling in parkinsonism.

Drooling is a frequent symptom in Parkinson's disease (PD), occurring in almost 75% of all patients. Although it is now well known that drooling in PD is the result of swallowing difficulties rather than excessive saliva production, few treatments have been developed to reduce it. Clinical studies suggest that botulinum toxin A (BTX) injections into salivary glands are effective in decreasing drooling in PD patients. In this double-blind, placebo-controlled study, 20 patients with parkinsonism (idiopathic PD or multiple system atrophy), were randomly assigned to receive 450 U of BTX (Dysport; Ipsen, Berkshire, UK) or 2 ml of placebo, injected into the parotids and submandibular glands under ultrasonographic guidance. Treatment efficacy and safety were assessed at baseline, 1 week and 3 months after BTX injections using clinical scales (Drooling Severity and Drooling Frequency scales) and side effects surveillance. After treatment, the average secretion of saliva in the BTX group was significantly lower than in the placebo group, as appraised by clinical measurements. No side effects were observed in either group. BTX injection into parotids and submandibular glands, under ultrasonographic guidance, is an effective and safe treatment for drooling in parkinsonism.