Therapeutic uses of botulinum toxin

Review article: botulinum toxin in the therapy of gastrointestinal motility disorders

Since 1980, botulinum toxin has been employed for the treatment of various voluntary muscle spastic disorders in the fields of neurology and ophthalmology. More recently, botulinum toxin has been proved to be effective in the therapy of dyskinetic smooth muscle disorders of the gastrointestinal tract. Achalasia and anal fissure are the gastrointestinal disorders in which botulinum toxin therapy has been most extensively investigated. Botulinum toxin is the best treatment option for achalasia in patients whose condition makes them unfit for pneumatic dilation or surgery. In anal fissure, botulinum toxin is highly effective and may become the treatment of choice. In the future, botulinum toxin application in the gastrointestinal tract will be extended to many other gastrointestinal disorders, such as non-achalasic motor disorders of the oesophagus, dysfunction of Oddi's sphincter, achalasia of the internal anal sphincter and others. This article describes the mechanism of action, rationale of employment, indications and side-effects of botulinum toxin application in smooth muscle disorders of the gastrointestinal tract, and compares the results of different techniques of botulinum toxin therapeutic application.

[Skin, wrinkles and botulinum toxin]

OBJECTIVE

To present an up-to-date analysis about the use of botulinum toxin for treating facial lines and wrinkles.Method. - A systematic search of the literature was conducted to select the most recent or relevant publications on this topic, through Medline.

RESULTS

Out of the 583 articles retrieved, 90 were finally selected for the study.

DISCUSSION

Validity of using botulinum toxin for cosmetic use is demonstrated, together with contra-indications and different methods to objectivate the results. The different available types of toxin are presented and compared. Modalities of preparation, conservation, and waste disposal are detailed. Anatomical bases of muscular facial balance are reviewed, with techniques of injection presented for each site, and also with adjunctive procedures. Complications and side effects are described and analysed. Most complications can be prevented through: perfect knowledge of local anatomy;use of small volumes;orientation of the needle bevel towards the muscle body, injection within the muscle body if thick, more superficial if thin;application of ice on the skin pre- and post-injecting. Adding epinephrin or diluting with xylocaïne and epinephrin is not commonly used.

CONCLUSION

Botulinum toxin has found its way as a major component of the therapeutic armamentarium. Its efficacy for facial rejuvenation has made it extremely popular, but its use does follow strict rules, and should be restricted to soundly trained practitioners.

Botulinum toxin for treatment of Frey's syndrome: report of two cases

Frey's syndrome is a phenomenon of hemifacial flushing and sweating after gustatory stimulus, usually secondary to surgical trauma over the parotid gland, although other injury mechanisms may be seen. It is accepted as a result of aberrant regeneration of facial autonomic nerve fibers. Treatment evolved from ineffective medical and surgical approaches to botulinum toxin. We evaluate the effectiveness and safety of botulinum toxin in the treatment of this complication in two patients.

Pneumothorax complicating botulinum toxin injection in the body of a dilated oesophagus in achalasia

Botulinum toxin is used for an increasing number of indications in the field of gastroenterology. We report a case in which injection of botulinum toxin in the dilated tubular oesophagus in a patient with achalasia was complicated by a pneumothorax necessitating suction drainage.

East-west differences in the organization of botulinum toxin use in nine Central European countries

Availability and quality of expensive treatment modalities such as botulinum toxin (BTX) largely depend on organizational aspects such as costs, reimbursement by insurance companies, expertise and facilities for expert training, and the propagation of research. To investigate which determinants influence the organization of BTX' use throughout nine Central European countries (Austria, Croatia, Czech Republic, Germany, Hungary, Italy, Slovakia, Slovenia and Switzerland) we sent out questionnaires to leading BTX experts and consulted data banks of manufacturers and bulletins of international organizations. In Western European countries, there is a tendency for users to organize themselves in formal groups and to concentrate on research whereas the way how BTX is provided is diverse regarding qualifications of specialists and institutions. In the post-communist Eastern European countries, we found a tendency towards a centralized system of reimbursement and BTX treatment seems to be more in the hands of neurologists than any other specialists. Strong correlations were observed between the number of BTX centres, degree of organization of user groups and number of scientific publications, on the one hand, and parameters of healthcare performance and socioeconomic determinants, on the other. Our study suggests that in the nine countries surveyed, organizational aspects of BTX use vary considerably, whilst similarities are based mainly on socioeconomic rather than socio-demographic determinants.

Toxicity of botulinum neurotoxins in central nervous system of mice

Botulinum neurotoxins (BoNTs) act specifically on cholinergic nerve terminals, where they cause a sustained block of acetylcholine release, and therefore they are powerful tools to study the role of cholinergic neurons in neuronal processes. Peripheral effects of BoNTs are widely documented while central effects have not been studied. Here, we report for the first time on the central toxicity of BoNT serotypes A and B following their direct intracerebroventricular (icv) injection in CD1 mice. The LD50 values were found to be in the range 0.5-1.0 x 10(-6)mg/kg. We recorded the following signs preceding animal death: piloerection and weight decrease appear first, followed by temperature decrease, eyelid closure, loss of sensorimotor reflexes, dehydration, dyspnea. Mice died of heart or respiratory failure. The surviving mice recovered completely within 4-6 days and regained the initial healthy conditions. At sub-lethal doses, the same clinical signs appear in a lighter form and with a longer time course.

Purification of fully activated Clostridium botulinum serotype B toxin for treatment of patients with dystonia

Clostridium botulinum serotype B toxins 12S and 16S were separated by using a beta-lactose gel column at pH 6.0; toxin 12S passed through the column, whereas toxin 16S bound to the column and eluted with lactose. The fully activated neurotoxin was obtained by applying the trypsin-treated 16S toxin on the same column at pH 8.0; the neurotoxin passed through the column, whereas remaining nontoxic components bound to the column. The toxicity of this purified fully activated neurotoxin was retained for a long period by addition of albumin in the preparation.

Comparison of botulinum toxin types A and B: a bilateral and double-blind randomized evaluation in the treatment of canthal rhytides

BACKGROUND

The obligate bacterium Clostridium botulinum produces exotoxins (A, B, C-1, C-2, D, E, F, G) that are serologically and antigenically distinct. All serotypes have similar neurotoxic properties resulting in flaccid muscle paralysis. Types A and B are commercially available and are used widely for the reduction of dynamic facial rhytides. Although extensive information is known about type A, type B has recently become available; however, there is a limited clinical familiarity. Some of the remaining unknown distinctions between the two subtypes are the extent of toxin diffusion from the site of injection, the onset of action, the dose equivalency, and the duration of effect.

OBJECTIVE

The purpose of this preliminary double-blind study was to compare the duration of muscle paralysis and rhytid reduction of botulinum toxin types A and B. Additional relevant information was obtained, all of which can be useful in toxin selection.

METHOD

Ten women, ages 28 through 60, voluntarily consented to undergo a double-blind trial and were randomly assigned to have botulinum toxin type A injected into one set of lateral canthal rhytides and toxin type B into the contralateral periocular region. Based on dose-ranging investigations performed in patients with cervical dystonia, participants received treatment at the lowest reported effective ratio of 1:50 (1 U of toxin type A to 50 U of toxin type B). Three injections of 5 U of type A (total 15 U) and three injections of 250 U of undiluted type B (total 750 U) were injected into the lateral fibers of the orbicularis oculi muscle.

RESULTS

Patients were evaluated at 7, 30, 60, and 90 days. Findings were compared by the treating physician, patient self-assessment, and photographic images.

CONCLUSION

All patients noted rapid and satisfactory reduction in the rhytides in both periocular areas. However, upon unblinding of the solutions at the same volumes with a 1:50 ratio, type B toxin was found to be associated with slightly more discomfort upon injection, quicker onset of action, a sensation of "tightness" of the treated area, and a briefer duration of muscle paralysis.

Extensor digitorum brevis test and resistance to botulinum toxin type A

We studied 22 patients with dystonia to determine the normal range of values for the extensor digitorum brevis (EDB) test, and to determine its sensitivity and specificity in detecting resistance to botulinum toxin type A (BTX-A). Three compound muscle action potentials (CMAPs) elicited by peroneal nerve stimulation were averaged before and 2 weeks after injection of 20 units of BTX-A into the EDB. Amplitude and area ratios were calculated by dividing the averaged postinjection CMAP by the averaged preinjection CMAP values. The difference in means of this ratio between clinically sensitive and resistant subjects was statistically significant (P < 0.002). A normal range of <0.45 for each ratio was determined by adding two standard deviations to the ratio mean of 14 clinically sensitive subjects. Four of five resistant patients had values outside the normal range. The EDB test is a simple quantitative method of detecting resistance to BTX-A, with a sensitivity of 80% and specificity of 94%.

Anal fissure

Anal fissure is a common condition with a characteristic presentation. Despite increased pharmaceutical options in the medical management of anal fissures, surgical therapy is not in danger of becoming obsolete. Lateral internal sphincterotomy remains an attractive option for many patients suffering from this painful condition.

Long-term efficacy of botulinum toxin A in treatment of various movement disorders over a 10-year period

Although botulinum toxin A (BTX) has been licensed in Canada for treatment of various movement disorders since 1990, few clinical studies regarding its long-term efficacy and side effects have been reported. We conducted a retrospective analysis of 235 patients who received BTX from our movement disorders clinic over a 10-year period (January 1990 to December 1999). A total of 2,616 treatment cycles (multiple injections) were administered to 235 patients with cervical dystonia (CD), hemifacial spasm (HS), blepharospasm (BP), and other movement disorders. Substantial benefit at 5 years was seen in most patients (90% in BP, 88% in HS, 63% in CD, 100% in jaw closing and lower limb dystonia, and 56% in writer's cramp). Benefit was maintained for up to 10 years in CD, HS, and BP data, with a 75.8% benefit reported. Twenty-eight percent of patients discontinued treatment during the follow-up period due to a variety of reasons. Of these, 9.1% of patients developed primary resistance, and 7.5% of patients secondary resistance. Adverse effects, mostly minor, developed in 27% of patients at any one time, occurring over 4.5% of treatment cycles. These were most frequently reported in blepharospasm (22 of 36 patients in 40 cycles), followed by hemifacial spasm (21 of 70 patients in 46 cycles), and cervical dystonia (17 of 106 in 28 cycles). Only 1.3% of patients discontinued therapy due intolerable adverse effects. The results show that BTX is a safe and effective treatment of various types of movement disorders, and most side effects are well tolerated. Discontinuation for any reason was also low after 5 years. Efficacy was maintained after long periods of treatment with high degree of patient satisfaction.

Botulinum toxin in pain management of soft tissue syndromes

Botulinum toxin is approved for the treatment of muscle overactivity associated with several disorders, such as dystonias. However, control of muscle spasm often results in pain relief as well. Effective relief of pain associated with myofascial pain syndrome provides a model for the use of botulinum toxin to relieve pain associated with other types of soft-tissue syndromes, such as fibromyalgia. Although the mechanisms that trigger the pain in these syndromes vary, recent data suggest that a central neuroplastic mechanism may contribute to many complex pain syndromes. Botulinum toxin therapy may be particularly useful in soft-tissue syndromes that are refractory to traditional treatment with physical therapy, electrical muscle stimulation, and other approaches. Although not used as first-line therapy for pain relief, botulinum toxin may decrease pain long enough for patients to resume more conservative therapy. A primary benefit of treatment with botulinum toxin is its long duration of action. Several studies have demonstrated the efficacy of botulinum toxin types A and B in treating several neuropathic pain disorders. Proper patient selection, injection technique, and dosing are critical to obtaining the best outcomes in managing pain with botulinum toxin. Additional study is needed to better characterize its use for the treatment of pain.

Sensory motor retuning: a behavioral treatment for focal hand dystonia of pianists and guitarists

OBJECTIVE

To evaluate the long-term effectiveness of sensory motor retuning (SMR), a new treatment for focal hand dystonia in musicians.

DESIGN

Prospective case series with an (adventitious) comparison group with 3- to 25-month follow-up in piano and guitar and 0- to 4-month follow-up in flute and oboe players.

SETTING

General community in Germany.

PARTICIPANTS

Eleven professional musicians.

INTERVENTION

Immobilization by splints of 1 or more digits other than the focal dystonic finger. This finger carried out repetitive exercises in coordination with 1 or more of the other digits for 1(1/2) to 2(1/2) hours a day for 8 consecutive days under therapist supervision. The subjects then were instructed to continue practice for 1 hour daily for 1 year.

MAIN OUTCOME MEASURES

Spectral analysis of the output of a dexterity-displacement device that continuously recorded digital displacement during finger movements and a dystonia evaluation scale on which patients rated how well they had just performed dystonic movement sequences and repertoire passages.

RESULTS

The 3 wind players (adventitious placebo controls) did not improve substantially. However, each pianist and guitarist showed marked and significant improvement in spontaneous repertoire performance without the splint. The first subject is now 25 months posttreatment.

CONCLUSIONS

Results suggest that SMR is of value for the treatment of focal hand dystonia in pianists and guitarists.

Factors influencing the therapeutic effect of muscle afferent block for oromandibular dystonia and dyskinesia: implications for their distinct pathophysiology

Oromandibular dystonia (OMD) is a focal dystonia manifested by involuntary masticatory and/or lingual muscle contractions. Muscle afferent block (MAB) by injecting anaesthetic and alcohol intramuscularly is recently used for the treatment of OMD. To study the factors affecting the efficacy of MAB, 44 patients with OMD were treated by local injection of lidocaine and ethanol. They were divided into four groups (spastic, rhythmic, dyskinetic, and task-specific) according to the pattern of incisal movement and involuntary contraction. We used a clinical scaling protocol in terms of four parameters (mastication, speech, pain, and discomfort) to evaluate the change of symptoms objectively. The relationship of improvement in clinical scores with various parameters was assessed statistically. The overall objective improvement was 60.2 +/- 29.5%. The scores decreased significantly (P<0.0001, paired t-test) after MAB. The maximal incisal velocity significantly correlated inversely with the clinical improvement, and MAB was particularly effective for spastic contraction. Dyskinetic and rhythmic groups showed variable and significantly less improvements than the spastic group. MAB is highly effective for OMD, but not for the patients with dyskinetic symptoms. The jaw movement pattern is an important factor for predicting the outcome. The difference in the response to MAB in OMD and oral and/or orofacial dyskinesia suggests the distinct pathophysiology between the two.

Endoscopic botulinum toxin injection for cricopharyngeal dysphagia

Twelve patients underwent 17 endoscopic injections of botulinum toxin type A in the cricopharyngeus muscle for the treatment of dysphagia and cricopharyngeal spasm over a 3-year period. The patient's charts were reviewed. Preoperative and postoperative symptoms, examination, and swallowing studies were reviewed. Eleven of the 12 patients had improvement in their symptoms, which lasted for a mean of 3.8 months. Two patients elected cricopharyngeal myotomy for permanent correction of their dysphagia. There was 1 case of postoperative neck cellulitis in an immunocompromised patient undergoing simultaneous excision of a thyroglossal duct cyst. We conclude that endoscopic injection of botulinum toxin is a relatively safe and viable technique for the treatment of dysphagia associated with cricopharyngeal spasm. It requires simple tools readily available to otolaryngologists. Larger, prospective controlled studies are necessary to establish its effectiveness and role in the management of this condition.

Botulinum toxin type A use in piriformis muscle syndrome: a pilot study

OBJECTIVE

This study was undertaken to test the hypothesis that intramuscular botulinum toxin type A decreases chronic pain attributed to piriformis muscle syndrome to a greater extent than a similar injection with vehicle (saline) alone.

DESIGN

This double-blind, single group, crossover study was performed at an outpatient university clinic. Nine women with chronic buttock, hip, and lower limb pain without evidence of lumbar disk herniation or nerve root impingement on imaging studies participated in the study. The analgesic efficacy of a fluoroscopic/electromyographically guided unilateral intramuscular piriformis injection with 100 units botulinum toxin type A was compared with a similar injection of vehicle alone. Visual analog pain scales (VASs) were used to measure pain intensity, distress, spasm, and interference with activities.

RESULTS

No differences in mean VASs were detected between groups at baseline or after injection with vehicle. However, decreases were observed between baseline and post-botulinum toxin type A injection mean VASs, but only in one of four categories (interference with activities). VASs from every time point (days) were also compared with the average baseline VASs. After injection with vehicle, decreases were detected, but only in one of the four categories (distress). In comparison, after injection with botulinum toxin type A, decreases were observed under all VAS categories.

CONCLUSIONS

VAS data suggest that intramuscular piriformis injection with 100 units of botulinum toxin type A can reduce pain to a greater extent than similar injections with vehicle alone.

Botulinum toxin type B for treatment of spasmodic dysphonia: a case report

Although treatment with botulinum toxin type A (BTXA) has become the standard of care for most patients with laryngeal dystonia, its use is limited by the development of resistance to the toxin in some patients. Botulinum toxin type B (BTXB) has been found to be safe and effective in the treatment of cervical dystonia, but it has not been used previously to treat spasmodic dysphonia. Our experience with BTXB in a patient who developed resistance to BTXA suggests that BTXB may be safe and effective for the treatment of laryngeal dystonia, as well.

The Use of Botulinum Toxin Type A in Headache Treatment

Four percent to 5% of the general population suffers from chronic daily or near daily headache. A majority of them are chronic migraine (transformed migraine), and the rest are chronic tension-type headaches. Prophylactic treatments of migraine and chronic tension-type headache are far from satisfactory because of lack of good efficacy, intolerable side effects, development of tachyphylaxis over long-term use, and drug interactions. Comorbidities and analgesic overuse complicate matters further. There has been an increasing search for more effective treatment for chronic headache, which would result in "modification of the disease." Botulinum toxin type A is an emerging treatment for such patients whose headaches are poorly controlled with currently available prophylactic pharmacotherapy or in patients who do not tolerate them and are unable to continue them. Contraindications to acute migraine therapy such as triptans may also be an indication for alternative treatments like botulinum toxin type A. A number of double blind and open-label trials have been done for migraine and chronic tension-type headache. Although some of the well designed double blind, placebo-controlled, randomized clinical trials are in progress, it has been the clinical experience of many physicians that botulinum toxin type A cuts down the frequency and severity of headaches, improves disability scales, improves quality of life, and reduces the need for acute medications. Repeated use of botulinum toxin type A is needed to sustain long-term improvement, and long-term results indicate lack of tachyphylaxis in the majority of patients. Botulinum toxin type A is well tolerated and totally free of many long-term side effects, which are seen with other prophylactic agents. The clinician may be well advised to consider botulinum toxin type A in the most refractory forms of chronic headaches including chronic migraine and chronic tension-type headache. Appropriate injection techniques, selection of injection sites, and appropriate doses are necessary for success.

Achalasia: a review of therapeutic options and outcomes

Advances in achalasia has led to the development of new therapeutic options. This review will focus on methodology and outcomes of two established techniques; pneumatic dilation and surgical myotomy; and one new technique, LES injection of botulinum A toxin.

Botulinum toxin injection versus surgical treatment for tennis elbow: a randomized pilot study

Surgical treatment is considered the last option for chronic tennis elbow. The purpose of this pilot study was to compare treatment with botulinum toxin infiltration of the wrist extensor, a less invasive method, with a surgical wrist extensor release (Hohmann operation). Forty patients were included in the prospective randomized study; one group of patients had surgery (n = 20), the other group of patients was treated with botulinum toxin (n = 20). The results of evaluations after 3, 6, 12, and 24 months are presented. One year after treatment 13 (65%) patients in the botulinum toxin group and 15 (75%) patients in the operative group had good to excellent results. Two years after treatment 15 patients in the botulinum toxin group (75%) had good to excellent results; four patients had been operated on after initial treatment with botulinum toxin Type A. Seventeen patients in the operative group scored good to excellent (85%) at 2 years. When analyzed with an overall scoring system, no differences were found between the two forms of treatment. Botulinum toxin infiltration, a less invasive technique, may be an alternative for surgical treatment of tennis elbow.

Treatment of chest pain in patients with noncardiac, nonreflux, nonachalasia spastic esophageal motor disorders using botulinum toxin injection into the gastroesophageal junction

OBJECTIVE

The aim of this study was to determine if botulinum toxin injection in the gastroesophageal junction improves symptoms in patients with noncardiac chest pain with a spastic esophageal motility disorder.

METHODS

Twenty-nine noncardiac chest pain patients with nonachalasia, nonreflux-related spastic esophageal motility disorders were enrolled in this open label trial of botulinum toxin injection at the gastroesophageal junction. Chest pain was the major complaint in all patients. Symptoms of chest pain, dysphagia, regurgitation, and heartburn were scored before and 1 month after botulinum toxin injection. A response to botulinum toxin was defined as at least a 50% reduction in the symptom score with a possible total chest pain score of 4. The duration of response was defined as the time period, between the time of injection and the point in time, at which the severity of the symptoms returned to the preinjection score.

RESULTS

Seventy-two percent of the patients responded with at least 50% reduction in chest pain. In these responders, there was a 79% reduction in the mean chest pain score from a preinjection score of 3.7 to a postinjection score of 0.78 (p < 0.0001). The mean duration of the response for chest pain in these patients was 7.3+/-4.1 months (range 1-18 months). There was also a significant reduction in the mean regurgitation score, dysphagia score, and total symptom score (p < 0.0001).

CONCLUSIONS

Botulinum toxin injection at the gastroesophageal junction leads to significant symptomatic improvement in patients with spastic esophageal motility disorders whose major complaint is chest pain.

Treatment of idiopathic gastroparesis with injection of botulinum toxin into the pyloric sphincter muscle

OBJECTIVES

We aimed to determine if botulinum toxin injection into the pyloric sphincter improves gastric emptying and reduces symptoms in patients with idiopathic gastroparesis.

METHODS

Patients with idiopathic gastroparesis not responding to prokinetic therapy underwent botulinum toxin (80-100 U, 20 U/ml) injection into the pyloric sphincter. Gastric emptying scintigraphy was performed before and 4 wk after treatment. Total symptom scores were obtained from the sum of eight upper GI symptoms graded on a scale from 0 (none) to 4 (extreme).

RESULTS

Ten patients were entered into the study. The mean percentage of solid gastric retention at 4 h improved from 27+/-6% (normal < 10%) before botulinum toxin injection into the pylorus to 14+/-4% (p = 0.038) 4 wk after treatment. The symptom score decreased from 15.3+/-1.7 at baseline to 9.0+/-1.9 (p = 0.006) at 4 wk, a 38+/-9% decrease. Improvement in symptoms tended to correlate with improved gastric emptying of solids (r = 0.565, p 0.086).

CONCLUSIONS

This initial pilot study suggests that botulinum toxin injection into the pylorus in patients with idiopathic gastroparesis improves both gastric emptying and symptoms.

Effect of botulinum toxin on endplate noise in myofascial trigger spots of rabbit skeletal muscle

OBJECTIVE

To assess the effect of botulinum toxin type A (BTX-A) on the endplate noise prevalence in rabbit myofascial trigger spots to confirm the role of excessive acetylcholine release on the pathogenesis of myofascial trigger points and to develop an objective indicator of the effectiveness of BTX-A in the treatment of myofascial trigger points.

DESIGN

Eighteen adult New Zealand rabbits were divided into three groups that received a single bolus of BTX-A over a myofascial trigger spot region on one side of the biceps femoris muscle. Another 10 rabbits received multiple-point injections in a myofascial trigger spot where endplate noises were found. A control study was performed on the other side of the biceps femoris muscle. The endplate noise prevalence in a myofascial trigger spot region was assessed.

RESULTS

It was found that injection of BTX-A reduced the prevalence of endplate noise. No significant differences between a single bolus injection and multiple-point injections were noted, although there was some evidence that multiple-point injections might maintain the endplate noise decreasing effect much longer than a single injection.

CONCLUSIONS

This study demonstrated the suppressive effect of BTX-A on endplate noise prevalence in a myofascial trigger spot region. The prevalence of endplate noise in the myofascial trigger point region may be a useful objective indicator for evaluating the therapeutic effectiveness of BTX-A injection to treat myofascial trigger points.

Botulinum neurotoxin A blocks cholinergic ganglionic neurotransmission in the dog heart

There is no data about whether botulinum neurotoxin inhibits the parasympathetic ganglionic neurotransmission in the heart, although botulinum toxin as a clinical drug inhibits the release of acetylcholine at the neuromuscular junction. Therefore, we investigated whether botulinum toxin (type A) injected into the sinoatrial (SA) fat pad inhibits decreases in heart rate induced by stimulation of the preganglionic parasympathetic nerves in the heart of the anesthetized dog. Stimulation of the parasympathetic nerves in the SA fat pad (SAP stimulation) prolonged the atrial interval but not the atrioventricular (AV) interval, and cervical vagus nerve stimulation (CV stimulation) prolonged both atrial and AV intervals. After botulinum toxin (20 or 25 mouse units) was injected into the SA fat pad, it gradually inhibited the prolongation of the atrial interval evoked by SAP and CV stimulations but not the prolongation of the AV interval evoked by CV stimulation. Conditioning successive stimulation of the cervical vagus nerves accelerated the inhibition by botulinum toxin of the chronotropic response to CV stimulation. These results indicate that selective injection of botulinum toxin into the SA fat pad blocks bradycardia mediated by parasympathetic ganglionic activation in the dog heart.

Pyloric injection of botulinum toxin for treatment of diabetic gastroparesis

BACKGROUND

Diabetic gastroparesis is a common clinical problem. The pathophysiology includes prolonged pyloric contractions that may cause functional resistance to gastric outflow. Botulinum toxin was injected into the pyloric sphincter in an attempt to decrease pyloric resistance and improve gastric emptying.

METHODS

Six patients with diabetic gastroparesis and an abnormal solid phase gastric emptying study underwent upper endoscopy during which 100 units of botulinum toxin were injected into the pyloric sphincter. Gastric emptying studies were obtained at 48 hours and 6 weeks after injection. Patients were questioned about symptoms of gastroparesis, and a symptom score was obtained at baseline and at 2 weeks and 6 weeks after injection.

OBSERVATIONS

There was a mean improvement in the subjective symptom score at 2 weeks of 55% (range 14% to 80%). This improvement was maintained at 6 weeks. There was a 52% improvement in gastric emptying at 2 and 6 weeks.

CONCLUSION

Pyloric injection of botulinum toxin can improve symptoms and gastric emptying in patients with diabetic gastroparesis. Further evaluation of pyloric injection of botulinum toxin as a treatment for diabetic gastroparesis is warranted.

Muscle strength following direct injection of doxorubicin into rabbit sternocleidomastoid muscle in situ

Direct intramuscular injection of doxorubicin results in permanent myofiber loss. A previous phase I trial demonstrated that such injections could successfully treat blepharospasm and hemifacial spasm. Our previous in vitro study demonstrated that doxorubicin resulted in a dose-dependent reduction in isometric force generation in sternocleidomastoid muscle in rabbits. This present study examined alterations in force generation in these treated muscles in situ, i.e., with the blood and nerve supply intact. Two months after a single doxorubicin injection, functional changes in peak twitch, tetanic force generation, and fatigue rate were assessed in control and doxorubicin-treated sternocleidomastoid muscles in rabbits. Peak force measurements were reduced in the treated muscles. These reductions in muscle strength were significantly greater at tetanic peak amplitudes. Fatigue rate was not altered by doxorubicin treatment of the sternocleidomastoid muscles. These findings support the potential clinical use of doxorubicin chemomyectomy for the treatment of patients with cervical dystonia.

Complications and adverse reactions with the use of botulinum toxin

Botulinum toxins are the causative agents of the severe food-borne illness botulism. With lethal doses approximating 10(-9) g/kg body weight, these neurotoxins represent some of the most toxic naturally occurring substances. Regardless, botulinum toxin is considered a safe therapy for inappropriate muscle spasms with adverse effects being typically self-limited. This article deals with some of the complications that have occurred with these treatments. The greatest concern with the use of BOTOX is probably the formation of blocking antibodies leading to nonresponse of subsequent treatment. Prevalence of resistance is less than 5%. Most complications associated with its aesthetic use are few and anecdotal. Nevertheless, the common problems and pitfalls associated with aesthetic treatment of the various areas of the face and neck with botulinum toxin are discussed. Also included are recommendations as to how to avoid these very undesirable, yet common, problems.

Head injury and posttraumatic movement disorders

WE REVIEW THE phenomenology, pathophysiology, pathological anatomy, and therapy of posttraumatic movement disorders with special emphasis on neurosurgical treatment options. We also explore possible links between craniocerebral trauma and parkinsonism. The cause-effect relationship between head injury and subsequent movement disorder is not fully appreciated. This may be related partially to the delayed appearance of the movement disorder. Movement disorders after severe head injury have been reported in 13 to 66% of patients. Although movement disorders after mild or moderate head injury are frequently transient and, in general, do not result in additional disability, kinetic tremors and dystonia may be a source of marked disability in survivors of severe head injury. Functional stereotactic surgery provides long-term symptomatic and functional benefits in the majority of patients. Thalamic radiofrequency lesioning, although beneficial in some patients, frequently is associated with side effects such as increased dysarthria or gait disturbance, particularly in patients with kinetic tremor secondary to diffuse axonal injury. Deep brain stimulation is used increasingly as an option in such patients. It remains unclear whether pallidal or thalamic targets are more beneficial for treatment of posttraumatic dystonia. Trauma to the central nervous system is an important causative factor in a variety of movement disorders. The mediation of the effects of trauma and the pathophysiology of the development of posttraumatic movement disorders require further study. Functional stereotactic surgery should be considered in patients with disabling movement disorders refractory to medical treatment.

Botulinum toxin B: a review of its therapeutic potential in the management of cervical dystonia

Botulinum toxins are well known as the causative agents of human botulism food poisoning. However, in the past two decades they have become an important therapeutic mainstay in the treatment of dystonias including cervical dystonia, a neurological disorder characterised by involuntary contractions of the cervical and/or shoulder muscles. The toxins inhibit acetylcholine release from neuromuscular junctions, producing muscle weakness when injected into dystonic muscles. Data from three double-blind, randomised, placebo-controlled trials demonstrate that botulinum toxin B effectively reduces the severity, disability and pain of cervical dystonia. In two of the trials, mean Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS)-Total score at week 4 (primary efficacy measure) after botulinum toxin B 10 000U was reduced by 11.7 (25%) or 11 (21%) compared with baseline. These changes were significantly greater than those obtained with placebo [4.3 (10%) or 2 (4%)] and were generally similar in patients who were responsive or resistant to botulinum toxin A. Statistically significant benefits compared with placebo were also evident for a range of other efficacy parameters including TWSTRS-Severity, -Pain and -Disability subscales, patient- assessed pain and patient-/physician-assessed global improvement ratings. In another trial, the percentage of patients with botulinum toxin A-resistant or -responsive cervical dystonia who had a > or =20% improvement in the TWSTRS-Total score between baseline and week 4 was significantly higher with botulinum toxin B 2500 to 10 000U (58 to 77%) than with placebo (27%). Overall, botulinum toxin B was generally well tolerated. The most frequently reported treatment-related adverse events were dry mouth and dysphagia. Most adverse events in patients receiving botulinum toxin B were mild or moderate; no serious adverse events or laboratory abnormalities were associated with the use of botulinum toxin B and, where reported, no patients discontinued from any of the clinical trials as a result of adverse events.

CONCLUSIONS

Botulinum toxin B has shown clinical efficacy in patients with cervical dystonia at doses up to 10 000U and is generally well tolerated. Its efficacy extends to patients who are resistant to botulinum toxin A. Although the potential for secondary resistance to botulinum toxin B remains unclear, it may occur less than with botulinum toxin A because methods for manufacturing commercially available botulinum toxin B do not include lyophilisation and the product does not require reconstitution before use. As injection with botulinum toxin is generally considered the treatment of choice for patients with cervical dystonia, botulinum toxin B should be considered a potential treatment option in this setting.

Effect of intramuscular botulinum toxin injection on upper limb spasticity in stroke patients

OBJECTIVE

To evaluate the therapeutic effect of intramuscular injection of botulinum toxin on spasticity of the upper limb, with emphasis on its influence over limb function.

DESIGN

An open-label, noncontrolled trial with a duration of 12 wk was designed to determine the safety and efficacy of intramuscular botulinum toxin A injection in the treatment of 16 patients with stroke with spastic hemiparesis. Electromyographically guided intramuscular botulinum toxin A injections were applied to the spastic limbs. A detailed scale system was used for the evaluation of muscle tone and functional changes induced by botulinum toxin A treatment.

RESULTS

No major side effect secondary to botulinum toxin A injection was reported. Statistically significant (P < 0.05) improvements of muscle tone, joint range of motion, hand muscle strength, and muscular pain were seen after the injection. The improvements lasted up to 8-12 wk after the treatment. However, there was no significant functional improvement except in two of the patients.

CONCLUSIONS

Botulinum toxin A injection may help relieve upper limb spasticity and pain in patients with stroke. Its effect on function is probably determined by case selection.

Respective potencies of Botox and Dysport: a double blind, randomised, crossover study in cervical dystonia

OBJECTIVES

Botulinum toxin type A is a potent neuromuscular paralyzing agent used in various disorders including cervical dystonia. Two preparations of botulinum toxin are now commercially available ( Dysport and Botox), but much controversy remains about their respective potencies. The aim of the study was to compare the efficacy of Botox with two different ratios of Dysport.

METHODS

A double blind, randomised, three period cross over study involving 54 patients with cervical dystonia was performed. The patients received the following treatments in a randomised order: Botox at the usually effective dose, Dysport at a dose of 1:3 (conversion factor of 3 between Botox and Dysport units-that is, one Botox unit=three Dysport units) and at a dose of 1:4 (conversion factor of four). The improvement of the Tsui (primary outcome criteria) and of the TWSTRS pain scales between baseline and a control visit 1 month after each of the three injections, as well as the incidence of adverse events, were assessed.

RESULTS

Comparison of the Tsui scores and of the TWSTRS pain scores showed a better effect on impairment and pain with Dysport 1:3 (p=0.02 and 0.04, respectively) and 1:4 (p=0.01 and 0.02, respectively) than with Botox. The number of adverse events was higher with both Dysport treatments. The most frequent adverse event was dysphagia, found in 3%, 15.6%, and 17.3% (Botox, Dysport 1:3 and 1:4, respectively) of the patients. No adverse event required withdrawal of therapy or specific management.

CONCLUSIONS

Dysport 1:3 (and Dysport 1:4 to a greater extent) is more efficient than Botox for both impairment and pain in cervical dystonia although with a somewhat higher incidence of minor adverse effects. This strongly suggests that the most appropriate conversion factor between Botox and Dysport units is less than 3 in cervical dystonia.

Cervical dystonia pathophysiology and treatment options

Dystonia is a syndrome of sustained involuntary muscle contractions, frequently causing twisting and repetitive movements or abnormal posturing. Cervical dystonia (CD) is a form of dystonia that involves neck muscles. However, CD is not the only cause of neck rotation. Torticollis may be caused by orthopaedic, musculofibrotic, infectious and other neurological conditions that affect the anatomy of the neck, and structural causes. It is estimated that there are between 60,000 and 90,000 patients with CD in the US. The majority of the patients present with a combination of neck rotation (rotatory torticollis or rotatocollis), flexion (anterocollis), extension (retrocollis), head tilt (laterocollis) or a lateral or sagittal shift. Neck posturing may be either tonic, clonic or tremulous, and may result in permanent and fixed contractures. Sensory tricks ('geste antagonistique') often temporarily ameliorate dystonic movements and postures. Commonly used sensory tricks by patients with CD include touching the chin, back of the head or top of the head. Patients with CD are classified according to aetiology into two groups: primary CD (idiopathic--may be genetic or sporadic) or secondary CD (symptomatic). Patients with primary CD have no evidence by history, physical examination or laboratory studies (except primary dystonia gene) of any secondary cause for the dystonic symptoms. CD is a part of either generalised or focal dystonic syndrome which may have a genetic basis, with an identifiable genetic association. Secondary or symptomatic CD may be caused by central or peripheral trauma, exposure to dopamine receptor antagonists (tardive), neurodegenerative disease, and other conditions associated with abnormal functioning of the basal ganglia. In the majority of patients with CD, the aetiology is not identifiable and the disorder is often classified as primary. Unless the aetiological investigation reveals a specific therapeutic intervention, therapy for CD is symptomatic. It includes supportive therapy and counselling, physical therapy, pharmacotherapy, chemodenervation [botulinum toxin (BTX), phenol, alcohol], and central and peripheral surgical therapy. The most widely used and accepted therapy for CD is local intramuscular injections of BTX-type A. Currently, both BTX type A and type B are commercially available, and type F has undergone testing. Pharmacotherapy, including anticholinergics, dopaminergic depleting and blocking agents, and other muscle relaxants can be used alone or in combination with other therapeutic interventions. Surgery is usually reserved for patients with CD in whom other forms of treatment have failed.

Treatment of achalasia with botulinum A toxin

Achalasia is an idiopathic neuromuscular disorder of the esophagus which is associated with absence of esophageal peristalsis and incomplete relaxation of a normal or raised lower esophageal sphincter (LES). Dysphagia is the most commonly associated symptom. Conventional therapeutic approaches are directed to reducing LES pressure and include orally-administered smooth muscle relaxants, forceful sphincter dilation with balloon dilators, and open or laparoscopic-assisted myotomy of the LES. Pharmacologic therapies have a low success rate. Forceful dilation has a perforation complication rate of 2% to 5%, and myotomies may precipitate significant gastroesophageal reflux, a complication minimized when a partial fundal wrap is employed simultaneously. In recent years, botulinum toxin, utilized widely as a striated muscle relaxant in managing blepharospasm, anal sphincter spasm, and muscle spasm complicating CVAs, and in smoothening facial wrinkles, has been extended to the management of achalasia on the basis that it impairs smooth muscle responsiveness to acetylcholine. Eighty units of Botox (botulinum toxin) are injected directly into the endoscopically (endoscopic ultrasound techniques may facilitate localization) located LES region (20 units into each of 4 quadrants). Symptom relief lasting 6 months on average is experienced in more than 65% of treated patients, and the complication rate is negligible. This therapeutic option is reserved for patients too ill to undergo any surgical procedure and is most effective when the lower esophageal region is hypertonic.

Pallidal deep brain stimulation in patients with cervical dystonia and severe cervical dyskinesias with cervical myelopathy

OBJECTIVES

Surgical treatment of complex cervical dystonia and of cervical dyskinesias associated with cervical myelopathy is challenging. In this prospective study, the long term effect of chronic pallidal stimulation in cervical dystonia and on combining the technique with spinal surgery in patients with severe cervical dyskinesias and secondary cervical myelopathy is described.

METHODS

Eight patients with a history of chronic dystonia who did not achieve adequate benefit from medical treatment or botulinum toxin injection participated in the study. Five patients had complex cervical dystonia with tonic postures and phasic movements. Three patients had rapidly progressive cervical myelopathy secondary to severe cervical dyskinesias and dystonia in the context of a generalised movement disorder. Quadripolar electrodes were implanted in the posteroventral lateral globus pallidus internus with stereotactic CT and microelectrode guidance. In the three patients with secondary cervical myelopathy, spinal surgery was performed within a few weeks and included multilevel laminectomies and a four level cervical corporectomy with spinal stabilisation.

RESULTS

Improvement of the movement disorder was noted early after pallidal surgery, but the full benefit could be appreciated only with a delay of several months during chronic stimulation. Three months after surgery, patients with cervical dystonia had improved by 38% in the severity score, by 54% in the disability score, and by 38% in the pain score of a modified version of the Toronto western spasmodic torticollis rating scale. At a mean follow up of 20 months, the severity score had improved by 63%, the disability score by 69%, and the pain score by 50% compared with preoperatively. There was also sustained amelioration of cervical dyskinesias in the three patients who underwent spinal surgery. Lead fractures occurred in two patients. The mean amplitude needed for chronic deep brain stimulation was 3.8 V at a mean pulse width of 210 micros, which is higher than that used for pallidal stimulation in Parkinson's disease.

CONCLUSIONS

Chronic pallidal stimulation is effective for complex cervical dystonia and it is a useful adjunct in patients with cervical dyskinesias and secondary cervical myelopathy who undergo spinal surgery.

Botulinum toxin use in facial plastic surgery

Botulinum toxin injection into specific mimetic facial muscle beds may be used alone or in conjunction with surgical modalities to rejuvenate the aging face and neck.

Botulinum toxin treatment for hyperlacrimation secondary to aberrant regenerated seventh nerve palsy or salivary gland transplantation

AIM

To investigate the potential of botulinum toxin A for treating hyperlacrimation.

METHODS

Three patients with unilateral symptoms of hyperlacrimation (diagnosed as "crocodile tearing") and one patient with a submandibular salivary gland transplant (SMGT) were studied. Tear production was quantified in the resting and stimulated (chewing or following exercise) state, using Schirmer's test and tear clearance. Lacrimal scintigraphy was used to assess outflow. Intraglandular injections (for patients with "crocodile tears") or periglandular injections (for the SMGT patient) of Dysport were administered in divided doses.

RESULTS

Two of the three eyes with reported gustatory lacrimation had a higher Schirmer test result than their fellow eye following gustatory stimulation. Scintigraphy, with and without stimulation, confirmed a patent drainage system in these patients. The other patient demonstrated a functional obstruction to tear flow. After treatment patients with confirmed gustatory lacrimation and the SMGT patient had a marked reduction in tearing at 2 weeks. This effect lasted 3-4 months. There was no demonstrable improvement in the patient with epiphora secondary to functional obstruction. Two patients who had received intraglandular injections developed a ptosis, which resolved spontaneously.

CONCLUSIONS

This study illustrates that gustatory lacrimation is a difficult diagnosis. In post-facial nerve palsy a functional element must always be considered. However, in confirmed hyperlacrimation botulinum toxin treatment is effective but side effects may occur.

Latanoprost in hemifacial spasm

An empirical observation that the prostaglandin derivate latanoprost quited facial spasms in patients with glaucoma prompted us to study latanoprost in non-glaucomatous patients with hemifacial spasms [HFS]. This explorative trial followed an open-label, prospective treatment design. At short term, most patients showed no or only mild improvement and subsequently needed therapy with Botulinum toxin A. Although these results are not impressive, latanoprost could be considered as an interesting alternative in the treatment of patients with HFS and with concomitant glaucoma. A role for prostaglandins in the trigeminofacial reflex is hypothesised.

An evaluation of the safety and efficacy of botulinum toxin type A (BOTOX) when used to produce a protective ptosis

PURPOSE

To evaluate the safety and efficacy of botulinum toxin type A (BOTOX, Allergan) when used to produce a protective ptosis in patients where a surgical tarsorrhaphy would otherwise be required.

METHODS

A total of 21 patients entered into the study. Doses of 2.5 and 5.0 units of BOTOX were injected into the levator palpebrae superioris muscle through the eyelid. The patients were followed daily where practical until a ptosis developed and then monitored 1-2 weekly until the ptosis was resolved. Injections were repeated, if necessary until the underlying condition had healed.

RESULTS

Ptosis took an average +/- SE of 4.0 +/- 0.5 days to develop (range 2-8 days). Duration of ptosis was an average +/- SE of 46.0 +/- 12.1 days (range 1-206 days). The effective dosage was 5 units of BOTOX in 0.1 mL. In 16 patients, the ptosis produced by BOTOX was sufficient to allow the underlying disease to heal and a surgical tarsorrhaphy was avoided. One patient required a surgical tarsorrhaphy and three patients required other surgical intervention to correct the underlying condition. One patient was lost to follow up. Diplopia was seen in five patients but resolved in all cases.

CONCLUSIONS

BOTOX was a suitable alternative to a surgical tarsorrhaphy.

Botulinum toxin type B: a new injectable treatment for cervical dystonia

Cervical dystonia (CD) causes involuntary muscle spasms and is often associated with pain. Recently, botulinum toxin type B (BTX-B) (Myobloc, Elan South San Francisco, CA, USA) was approved for general use in the treatment of CD in the USA. In two large pivotal trials, BTX-B was found to be safe and effective in decreasing the movements, pain and disability associated with CD. Benefits were noted both in patients who no longer respond and in those who continue to respond to botulinum toxin type A (BTX-A). BTX-B offers an additional therapeutic option for patients with CD.

Hemifacial spasm: intraoperative electromyographic monitoring as a guide for microvascular decompression

OBJECTIVE

Microvascular decompression is the logical and well-accepted treatment of choice for hemifacial spasm (HFS). In experienced hands, good to excellent results can be obtained. However, sometimes the exact site of the vascular compression is unclear. The aim of this study was to analyze whether intraoperative monitoring by stimulated electromyography of the facial nerve may help to improve the results of vascular decompression for HFS.

METHODS

In a series of 74 patients operated for HFS, the impact of intraoperative facial nerve monitoring on the surgical procedure was analyzed by use of the clinical and operative patient records. The role of this type of monitoring, with assessment of the so-called abnormal muscle response, was broken down into four categories: a guiding, a confirming, an indirect confirming, or an inconclusive role. The relationship between abnormal muscle response monitoring results and final surgical outcome was analyzed.

RESULTS

The overall cure rate was 87.8%, including patients who had previously undergone unsuccessful operations. Complications were minor, and hearing impairment was found in 2.7% of patients. A guiding role of intraoperative monitoring was apparent in 33.8% of patients, and a confirming role was demonstrated in 52.7% of patients, which resulted in a positive contribution of approximately 87% for intraoperative facial monitoring in microvascular decompression for HFS. In patients defined as guiding cases, the cure rate was 92%.

CONCLUSION

This study demonstrates the applicability and usefulness of intraoperative facial nerve monitoring in microvascular decompression operations for HFS.

Cervical dystonia severity scale reliability study

Cervical dystonia (CD) is characterized by sustained contractions of the neck musculature, resulting in abnormal head postures. The Cervical Dystonia Severity Scale (CDSS) was developed to provide a reliable measure of treatment response in patients with CD. The CDSS uses a protractor and wall chart to rate the severity of the head's deviation from neutral in each of three planes of motion (rotation, laterocollis, anterocollis/retrocollis), which is then scored in 5 degree intervals (1 degree to 5 degrees deviation = 1; 86 degree to 90 degrees deviation = 18). To test the reliability of the CDSS, four centers, each with two independent examiners, evaluated 42 patients with CD. At each site, each of the two examiners used the CDSS to evaluate the head position of each patient twice, on the same day, for a total of four evaluations. The kappa value for intra-examiner agreement was 0.94 (95% confidence limit of 0.900-0.972), indicating excellent intra-examiner reliability. The kappa value for interexaminer reliability was 0.79 for the first evaluation and 0.86 for the second evaluation (95% confidence limits of 0.668-0.920 and 0.790-0.920) indicating excellent interexaminer reliability. Thus, the CDSS was highly reliable in both intra-examiner and interexaminer scoring comparisons.

Botulinum toxin type A induces apoptosis in nasal glands of guinea pigs

Nasal hypersecretion is predominantly caused by overaction of nasal glands, which are mainly under cholinergic control. In this work, we investigated the influence of botulinum toxin A (BTA) on the nasal mucosal tissue of the maxillary sinus turbinates of guinea pigs (n = 10) that were painlessly sacrificed 10 days (short-term group) or 3 months (long-term group) after local treatment with 20 units of BTA (Botox) or 0.2 mL of 0.9% sodium chloride (control). Histologic investigation of the nasal mucosal tissue of the BTA-treated animals (short-term group) showed degeneration of glands and ducts and apoptotic nuclei on TUNEL staining of these structures. The control animals revealed normal glandular tissue and no apoptosis. The animals of the long-term group showed almost normal glandular tissue and only a few apoptotic nuclei. In conclusion, BTA induces temporary apoptosis in the nasal glandular compartment of guinea pigs.