Initial North American experience with botulinum toxin type A for treatment of anismus

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.

[Digestive tract and botulinum toxin]

INTRODUCTION

the aim of this work was to check literature to assess botulinum toxin injection efficacy in gastrointestinal motor disorders with special emphasis on controlled clinical trials.

METHODS

literature was carried out with the Medline data bank.

RESULTS

seventy three articles in French and in English including a recent general review were retained. Comparative clinical trials only concerned achalasia and anal fissure. The other gastrointestinal motor disorders only gave rise to open non-controlled trials assessed on clinical end points.

DISCUSSION

this review of literature helps to determine usefulness and safety of Botulinum toxin injection in the treatment of esophageal achalasia and anal fissure. The main limitation is its brief duration of action. Studies concerning the others spastic motor disorders are based on unknown physiopathology and controlled trials are required to assess its efficacy.

CONCLUSION

botulinum toxin is increasingly used for gastrointestinal motor disorders with worthwhile results. Its efficacy has been yet established for only two disorders : it has a valuable palliative role in achalasia and may be curative for anal fissure.

Constipation: evaluation and treatment

Constipation is a common clinical problem that comprises a constellation of symptoms that include excessive straining, hard stools, feeling of incomplete evacuation, use of digital maneuvers, or infrequent defecation. Although many conditions, such as metabolic problems, fiber deficiency, anorectal problems, and drugs, can cause constipation, when excluded functional constipation consists of two subtypes: slow-transit constipation and dyssynergic defecation. Some patients with irritable bowel syndrome may exhibit features of both types of constipation. The Rome criteria for functional constipation together with modifications proposed here for dyssynergic defecation may serve as useful guidelines for making a diagnosis. Recent advances in technology, together with a better understanding of the underlying mechanisms, have led to real progress in the diagnosis of this condition. Management options are limited, however, and evidence to support these treatments is only modest. The treatment is primarily medical; surgical options should be reserved for refractory disease and after careful diagnostic work-up. Although laxatives remain the mainstay of therapy, prokinetics that are colon-selective are optimal for treating patients with slow-transit constipation, but they are not yet available for clinical use. Recent controlled trials, however, are promising. Biofeedback therapy is the preferred treatment for patients with dyssynergia, but is not widely available. In the near future, user-friendly biofeedback programs including home therapy may facilitate wider use of these methods for patients with dyssynergic defecation.

Side effects of botulinum toxin injection for benign anal disorders

BACKGROUND

Botulinum toxin A (BT-A) is a powerful biological toxin. Nevertheless, it has proved to be a remarkable therapeutic agent for the treatment of benign anal disorders. Higher doses of BT-A could change the outcome of treatment. It is not known whether doses of BT-A higher than 20 units of Botox (or corresponding doses of Dysport) are as safe for patients as lower doses of BT-A.

METHODS

The side effects of BT-A injections in the treatment of chronic anal fissure (105 patients) and functional outlet obstruction (34 patients) were analysed prospectively. The patients received at least 25 units of Botox or 150 units of Dysport.

RESULTS

The patients with chronic anal fissure complained of incontinence of flatus (one severe case and eight mild cases), incontinence of faeces (five mild cases), anal haematoma (five cases), flu-like syndrome (three cases), an acute inflammation of external anal varices (two cases), epididymitis (one case) and haemorrhoid prolapse (one case). Patients with anismus suffered from intertrigo (one case); the pain after injection lasted for 2-4 days (four cases). No life-threatening side effects after 181 injections of BT-A were observed. Most of the side effects were only transient symptoms. No significant interdependence between injection methods (injection into one or two sites) and the risk of side effects was found.

CONCLUSION

Treatment with BT-A is safe. Despite the application of higher doses of BT-A in the treatment of benign anal disorders so far, no severe side effects were observed.

Botulinum neurotoxin and other treatments for fissure-in-ano and pelvic floor disorders

BACKGROUND

The management of disorders of the lower gastrointestinal tract, such as chronic anal fissure and pelvic floor dysfunction, has undergone re-evaluation recently. To a large extent this is due to the advent of neurochemical treatments, such as botulinum neurotoxin injections and topical nitrate ointment.

METHODS AND RESULTS

This review presents, inter alia, current data on the use of botulinum neurotoxin to treat lower gastrointestinal tract diseases, such as chronic anal fissure for which it promotes healing and symptom relief in up to 70 per cent of cases. This agent has also been used selectively to weaken the external anal sphincter and puborectalis muscle in constipation and in Parkinson's disease. Symptomatic improvement can also be induced in anterior rectocele by botulinum neurotoxin injections.

CONCLUSION

Botulinum neurotoxin appears to be a safe therapy for anal fissure. It is more efficacious than nitrate application and does not require patient compliance to complete treatment. While it may also be a promising approach for the treatment of chronic constipation due to pelvic floor dysfunction, further investigation of its efficacy and safety in this role is needed before general usage can be advocated.

Sacral magnetic stimulation in puborectalis paradoxical syndrome

BACKGROUND AND PURPOSE

Our earlier studies have demonstrated that sacral magnetic stimulation (MS) in the canine model, in healthy volunteers and in constipated subjects effected rectal pressure rise, decline of the rectal neck (anal canal) pressure as well as rectal evacuation. Based on these results, we studied the effect of sacral MS on defecation in patients with puborectalis paradoxical syndrome (PPS).

METHODS

Eleven subjects (8 women, 3 men; age 36-53 years) with PPS were enrolled in the study. The magnetic coil was placed on the back with its center located between L4 and L5. Stimulation parameters were set at 70% of maximum intensity, 40 Hz frequency and 2-second burst length with 2 seconds off. During MS, the rectal neck and gastric (intra-abdominal) pressures were measured. The procedure was performed in the empty and in the full rectum using the balloon expulsion test in the latter.

RESULTS

MS of the empty and balloon-filled rectum effected rise of the rectal pressure (p < 0.001), decline of the rectal neck pressure (p > 0.001) and no significant change of the intragastric pressure (p > 0.05). The balloon was expelled to the exterior in all the patients.

CONCLUSIONS

Sacral MS succeeded in dispelling to the exterior the water-filled rectal balloon. The method is simple, easy, non-invasive, non-radiologic and can be performed on an outpatient basis for the treatment of PPS.

Botulinum toxin type-A in therapy of patients with anismus

INTRODUCTION

Anismus is a common cause of constipation and outlet obstruction. Standard therapy with laxatives or biofeedback has conflicting results. Surgical treatment gives poor results and has practically been abandoned.

PURPOSE

This study was designed to evaluate the efficacy of botulinum toxin type-A (Botox) injection to the puborectalis muscle in patients with anismus.

METHODS

Twenty-five patients (15 females; mean age, 23.2) with history of constipation and symptoms of outlet obstruction underwent anorectal perfusion manometry and video-proctography. All patients were found to have a nonrelaxing puborectalis muscle on both modalities. All have been unable to expel a rectal balloon. Each patient who participated in the study was randomly assigned to undergo local injection of Botox--10 units to each side of the puborectalis or 20 units to the posterior aspect of this muscle. Eight patients underwent further injections1-5 every 3 months in accordance with previous results. Follow-up was conducted 1, 4, 12, and 24 weeks after injection. Straining, anorectal pain, and overall satisfaction were assessed on a visual analog scale. Weekly evacuation, fecal incontinence, and complications were recorded. At the weekly meeting, each patient underwent anorectal manometry with a balloon expulsion test.

RESULTS

Manometric relaxation was achieved after the first injection in 18 patients (75 percent). Once relaxation was achieved, it lasted throughout the follow-up. Nine patients (37.5 percent) expelled the rectal balloon after the first injection. Seven of 16 patients who failed the first injection had an additional one. In 2 patients it was successful (28.6 percent). Symptom improvement of 29.2 percent in straining index was recorded during follow-up. In 3 patients (12.5 percent) pain developed after injection. No other complications were observed. Overall satisfaction with Botox injection results was observed in 58.3 percent.

CONCLUSIONS

Botox injection to the puborectalis muscle has been found to have a limited therapeutic effect on patients suffering from anismus. Our results justify the need for further double-blind placebo-controlled trials to determine the exact role of botulinum toxin type-A in anismus.

Review article: the therapy of constipation

Constipation is a common symptom that may be idiopathic or due to various identifiable disease processes. Laxatives are agents that add bulk to intestinal contents, that retain water within the bowel lumen by virtue of osmotic effects, or that stimulate intestinal secretion or motility, thereby increasing the frequency and ease of defecation. Drugs which improve constipation by stimulating gastrointestinal motility by direct actions on the enteric nervous system are under development. Other modalities used to treat constipation include biofeedback and surgery. Laxatives and lavage solutions are also used for colon preparation and evacuation of the bowels after toxic ingestions.

Anterior rectocele due to obstructed defecation relieved by botulinum toxin

Background. Surgical repair of rectocele does not always alleviate symptoms related to difficulty in defecation, and some patients have impaired fecal continence after surgical treatment. To avoid complications of surgical repair, we investigated the efficacy of botulinum toxin in treating patients with symptomatic rectocele. Methods. Fourteen female patients with anterior rectocele were included in the study. The patients were studied by using anorectal manometry and defecography, and then treated with a total of 30 units of type A botulinum toxin, injected into 3 sites, 2 on either side of the puborectalis muscle and the third anteriorly in the external anal sphincter, under ultrasonographic guidance. Results. After 2 months, symptomatic improvement was noted in 9 patients (P =.0003). At the same time, rectocele depth (mean +/- SD) was reduced from 4.3 +/- 0.6 cm to 1.8 +/- 0.5 cm (P =.0000001) and rectocele area from 9.2 +/- 1.3 cm(2) to 2.8 +/- 1.6 cm(2) (P =.0000001). Anorectal manometry demonstrated decreased tone during straining from 70 +/- 28 mm Hg at baseline to 41 +/- 19 mm Hg at 1 month (P =.003) and to 41 +/- 22 mm Hg at 2 months (P =.005). No permanent complications were observed in any patient for a mean follow-up period of 18 +/- 4 months. At 1 year evaluation, incomplete or digitally assisted rectal voiding was not reported by any patient, and a rectocele was not found at physical examination. Four recurrent, asymptomatic rectoceles were noted at defecography. Conclusions. Botulinum toxin injections should be considered as a simple therapeutic approach in patients with anterior rectocele. The treatment is safe and less expensive than surgical repair. A more precise method of toxin injections under transrectal ultrasonography accounts for the high success rate. Repeated injections may be necessary to maintain the clinical improvement.

Indications and efficacy of botulinum toxin in disorders of the gastrointestinal tract

In recent years, botulinum toxin type A (BT) has been found to be effective in the treatment of various spastic disorders of smooth muscle in the upper and lower gastrointestinal tract. The short-term efficacy of intrasphincteric injection of BT in achalasia is now well established, however, because of the chronic nature of the disease, patients will require repeated injections at regular intervals. In contrast, after a single injection into the anal sphincter, BT has impressively high healing rate with minimal side effects. BT remains a novel therapeutic approach in a range of other gastrointestinal motility disorders including diffuse oesophageal spasm, sphincter of Oddi dysfunction and anismus, and the list of its indications is increasing. BT seems to be safe but as its long-term effects remain unestablished, it should be used with caution in younger patients. In this review we discuss the mechanism of action, indications, efficacy and side-effects of BT with its use in various areas of gastrointestinal tract.

Dyssynergic defecation

Dyssynergic defecation is a common clinical problem that affects half of patients with chronic constipation. In many patients, there is a significant overlap with slow transit constipation. The chief underlying pathophysiologic mechanism is a failure of rectoanal coordination. By using a combination of history, prospective stool diaries, detailed clinical evaluation, and anorectal physiologic tests, it is possible to diagnose this problem. Controlled trials are under way to evaluate the efficacy of biofeedback therapy. Meanwhile, it is possible to treat most patients by using neuromuscular conditioning and biofeedback therapy. Further refinements in diagnostic criteria and in rehabilitation therapy programs should facilitate better diagnosis and treatment of patients with dyssynergic defecation.

Reproducibility of colonic transit study in patients with chronic constipation

PURPOSE

Major therapeutic decisions are rendered based on a single colonic transit study. Therefore, the aim of this study was to assess the reproducibility of colonic transit time in patients with chronic constipation.

MATERIALS AND METHODS

Fifty-one patients with chronic idiopathic constipation were randomly selected to undergo two separate colonic transit tests. All clinical conditions, methodology, and patients' instructions were identical on both occasions. The gamma rate (linear correlation analysis) was undertaken between the first and second colonic transit times. Groups were divided according to the diagnoses of colonic inertia (slow-transit constipation), paradoxical puborectalis contraction, and chronic idiopathic constipation (normal-transit constipation).

RESULTS

In 35 of 51 patients (69 percent), the results were identical between the two studies; however, in 16 patients (31 percent), the results were disparate (gamma correlation coefficient = 0.53; P < 0.01). The specific correlation coefficients for patients with colonic inertia, paradoxical puborectalis contraction, and chronic idiopathic constipation were 0.12, 0.21, and 0.60 (P < 0.01), respectively. Moreover, the success rate of colectomy for colonic inertia was significantly higher in patients who underwent a repeat transit study confirming inertia than in patients who underwent colectomy based on a single study.

CONCLUSIONS

Overall, colonic transit time is reproducible in patients with chronic constipation. The correlation coefficient is best for patients with idiopathic constipation and worst for patients with colonic inertia. This new finding suggests that suboptimal surgical outcome may be attributable to inaccurate diagnosis. Because of this poor correlation coefficient, in patients with colonic inertia, consideration should be given to repeating the colonic transit study before colectomy to help secure the diagnosis and improve outcome.

Pharmacotherapy with botulinum toxin: harnessing nature's most potent neurotoxin

Botulinum toxin (BTX), a potent biologic neurotoxin, commonly is associated with lethal outbreaks of food poisoning; however, it also plays a role as a therapeutic agent. Since the 1970s physicians have investigated BTX therapy in patients with neurologic disorders. The number of applications greatly expanded over the years to include certain focal dystonias (blepharospasm, torticollis, laryngeal dystonias, writer's cramp), strabismus, and a wide variety of other indications (gastrointestinal disorders, cosmetic wrinkle correction, spasticity, hyperhidrosis). BTX's safety and efficacy are reviewed.

Botulinum toxin in the treatment of outlet obstruction constipation caused by puborectalis syndrome

PURPOSE

Puborectalis syndrome has been difficult to treat. We investigated the efficacy of botulinum toxin in treating patients with puborectalis syndrome who had previously failed to respond to electromyographic biofeedback sessions and who refused to use anal dilators.

METHODS

Of a group of 50 patients with chronic outlet obstruction constipation, four patients with puborectalis syndrome were included in the study. The patients were studied using anorectal manometry, defecography, and electromyography and then treated with 30 units of Type A botulinum toxin, injected into two sites on either side of the puborectalis muscle, under ultrasonographic guidance.

RESULTS

One patient was lost to follow-up. After treatment in other patients, the frequency of natural bowel movements increased from zero to six per week and laxatives were needed by only one patient. Anorectal manometry demonstrated decreased tone during straining from (mean +/- standard deviation) 96.2 +/- 12 mmHg to 42.5 +/- 13 mmHg at four weeks (P = 0.003) and 63.2 +/- 22 mmHg at eight weeks (P = 0.009). Defecography performed eight weeks after treatment showed improvement in the anorectal angle, which increased from 94 +/- 11 degrees to 114 +/- 13 degrees (P = 0.01), and evacuation of barium paste. Electromyography demonstrated mild paradoxical contraction. However, 16 weeks after treatment one of these three patients suffered symptomatic recurrence. This patient was re-treated with 50 units of toxin; eight months later he required a further 60 units. Seven months after the last injection he reported normal daily bowel movements without the use of laxatives.

CONCLUSIONS

Botulinum toxin injection should be considered as a simple therapeutic approach in patients with puborectalis syndrome. The use of higher dosage and a more precise method of toxin injections under transrectal ultrasonography account for the long-term higher success rate. However, because the effects of the toxin wear off within three months of administration, repeated injections could be necessary to maintain the clinical improvement.

Endoscopic botulinum toxin injection into the minor papilla for treatment of idiopathic recurrent pancreatitis in patients with pancreas divisum

BACKGROUND

In some patients with pancreas divisum, obstruction to the flow of pancreatic juice into the duodenum is the presumptive cause of acute recurrent pancreatitis. However, identification of those patients who may benefit from minor papilla sphincterotomy or stent placement is difficult.

METHODS

Five patients with acute recurrent pancreatitis and pancreas divisum were therefore treated by endoscopic injection of 50 units of botulinum toxin into the minor papilla in an outpatient setting.

RESULTS

Botulinum toxin injection was successfully performed on six occasions in 5 patients and no adverse effects were noted. Two patients relapsed after 9 and 10 months, respectively, but had definite relief of symptoms after needle-knife sphincterotomy. One patient relapsed 7 months after botulinum toxin injection but became symptom free again after a second botulinum toxin injection. Another patient is still in clinical remission 4 months after botulinum toxin administration, and 1 patient did not respond to either botulinum toxin administration or to sphincterotomy and stent placement.

CONCLUSIONS

Endoscopic injection of botulinum toxin into the minor papilla in patients with pancreas divisum and acute recurrent pancreatitis is a safe procedure that is easy to perform and provides short-term relief in some patients. Response to botulinum toxin injection may predict whether patients with pancreas divisum and acute recurrent pancreatitis will benefit from other forms of endoscopic therapy.

Constipation, diarrhea, and irritable bowel syndrome

Constipation, diarrhea, and irritable bowel syndrome are commonly encountered in the primary care practice. Most episodes of constipation and diarrhea are benign and self-limited. Patients with chronic constipation should undergo a screening evaluation to exclude organic disease, after which most can be managed successfully with dietary modification and fiber supplementation. The cause of chronic diarrhea usually can be discerned clinically, with irritable bowel syndrome, inflammatory bowel disease, and lactose intolerance being diagnosed most frequently. Irritable bowel syndrome is a functional gastrointestinal disorder characterized by abdominal pain and disordered defecation, which is successfully managed with a strong physician-patient relationship and periodic pharmacologic intervention.

Identification of patients likely to benefit from biofeedback for outlet obstruction constipation

BACKGROUND

Biofeedback for outlet obstruction constipation has a varying success rate. The aim of this study was to identify which patients are likely to respond to biofeedback.

METHODS

Thirty patients with severe outlet obstruction constipation were treated by a specialist nurse using three or four sessions of visual and auditory feedback of anal sphincter pressures. All patients were assessed by evacuating proctography, whole-gut transit studies and anorectal physiology before treatment.

RESULTS

Two patients did not complete the course of biofeedback. Nine patients improved. Before treatment these patients had predominantly normal anorectal physiology and were all able to open the anorectal angle at evacuating proctography. Nineteen patients did not improve, of whom only three had no measured abnormality other than inability to empty the rectum. Ten of these patients had abnormal anorectal physiology which may have been due to previous vaginal delivery.

CONCLUSION

Biofeedback for outlet obstruction constipation is more likely to be successful in patients without evidence of severe pelvic floor damage.

Botulinum toxin injections in the internal anal sphincter for the treatment of chronic anal fissure: long-term results after two different dosage regimens

OBJECTIVE

To investigate the effects of two different dosage regimens of botulinum toxin to induce healing in patients with idiopathic anal fissure.

SUMMARY BACKGROUND DATA

Chronic anal fissure is maintained by contraction of the internal anal sphincter. Sphincterotomy, which is successful in 85% to 95% of patients, permanently weakens the sphincter and therefore might be associated with anal deformity and incontinence.

METHODS

Fifty-seven consecutive outpatients were evaluated. Type A botulinum toxin was injected into the internal anal sphincter.

RESULTS

Patients were divided into two treatment groups based on the number of botulinum toxin units injected. Patients in the first group were treated with 15 units and retreated with 20 units. Patients in the second group were treated with 20 units and retreated with 25 units. Two months after treatment, 10 patients in the first group and 23 patients in the second group had a healing scar. Symptomatic improvement was observed in 13 patients in the first group and in 24 patients in the second group. Statistical analysis showed that resting anal pressure varied from baseline values as a function of treatment; in contrast, the treatment had no effect on maximum voluntary pressure. Long-term healing was achieved in 13 patients in the first group and in all patients in the second group who underwent a complete treatment.

CONCLUSIONS

Botulinum toxin is safe and effective in the treatment of anal fissure. It is less expensive and easier to perform than surgical treatment. No adverse effects resulted from injections of the toxin. The higher dosage is effective in producing long-term healing without complications.

Obstructive defecation: a failure of rectoanal coordination

OBJECTIVE

The pathophysiology of obstructive defecation is unclear. We investigated whether impaired rectoanal coordination causes obstructive defecation and if this dysfunction can be corrected by biofeedback therapy.

METHODS

We prospectively studied 25 healthy subjects and 35 consecutive patients with constipation (>1 year) with anorectal manometry and balloon expulsion test. Symptoms were assessed from diary cards. Patients found to have obstructive defecation were offered biofeedback therapy. After treatment, their defecation dynamics and symptoms were reassessed.

RESULTS

Eighteen patients had obstructive defecation and 17 had normal defecation dynamics (nonobstructive). Five normals (20%) exhibited obstructive pattern but only one failed to expel balloon. In the obstructive group, during straining, the intrarectal pressure and defecation index were lower (p < 0.05), and anal residual pressure was higher (p < 0.01) when compared with the nonobstructive group or normals. After biofeedback therapy, the intrarectal pressure and defecation index increased (p < 0.02) and anal residual pressure decreased (p < 0.001); stool frequency, degree of straining, and bowel satisfaction scores improved (p < 0.05); 67% stopped laxatives and 11 patients discontinued stooling with digitation.

CONCLUSION

Patients with obstructive defecation showed impaired rectal contraction, paradoxical anal contraction, or inadequate anal relaxation. These features suggest that rectoanal coordination was impaired. Biofeedback therapy rectified these pathophysiological disturbances and improved constipation.

Nerve injection injury with botulinum toxin

The therapeutic use of botulinum toxin (Botox) is increasing in popularity. Previous studies have shown that various drugs, especially when injected intrafascicularly, can cause major nerve damage. This study evaluates the potential for neurotoxicity of botulinum toxin in a rat sciatic nerve model. Lewis rats were randomly assigned to one of six groups (n = 10/group). Group 1, 2, and 3 rats received, respectively, an intrafascicular, extrafascicular, and extraneural injection of 50 microl of botulinum toxin (50 UI/ml). Group 4, 5, and 6 rats received 50 microl of 10% phenol as a positive control. Five animals received saline as a negative control. Animals were sacrificed at 2 and 7 weeks. Nerves were harvested and processed for histology and morphometry. Nerves in all botulinum toxin groups retained a normal architecture without cellular infiltration or demyelination. The number and diameter of fibers, the thickness of myelin, and the percentage of neural tissue were comparable with normal controls. Nerves injected intraneurally with phenol presented with severe damage, demyelination, and inflammation at 2 weeks and showed signs of early regeneration at 7 weeks. This study demonstrates that in a rat model, even direct intraneural injection of botulinum toxin caused no damage. This information should encourage the reconstructive surgeon to consider broader applications of this drug.