Side effects of botulinum toxin injection for benign anal disorders

Effectiveness and safety of botulinum neurotoxin for treating dyssynergic defecation: A systematic review and meta-analysis

Dyssynergic defecation (DD) is a common cause of chronic constipation. Owing to the lack of a comprehensive synthesis of available data on the effectiveness of botulinum neurotoxin (BoNT) for treating DD, we performed a systematic review and meta-analysis. We searched the PubMed, Embase, and Cochrane databases from inception to May 9, 2023. The outcomes comprise short-term and long-term symptom improvement, various anorectal function measurements, complications of fecal incontinence, and symptom improvement after repeated BoNT injections. A meta-analysis comparing BoNT injection with either surgery or biofeedback (BFB) therapy in treating DD was also conducted. Subgroup analysis and meta-regression were performed to identify possible moderator effects. We included five randomized controlled trials, seven prospective studies, and two retrospective observational studies. Short-term potential improvement in symptoms (event rate [ER], 66.4%; 95% CI, 0.513 to 0.783) was identified, but in the long-term (>12 months), this effect was decreased (ER, 38.2%; 95% CI, 0.267 to 0.511). Short-term improvements in objective anorectal physiologic parameters were also observed. Repeated BoNT injection was effective for patients with symptom recurrence. Subgroup analysis revealed enhanced long-term symptom improvement with high-dose BoNT, but this treatment also increased the risk of complications and recurrence compared with low doses. The effectiveness, complications, and recurrence of symptoms associated with BoNT injection and surgery did not differ significantly. BoNT injection significantly provided short-term symptom improvement but also heightened the risk of incontinence compared with BFB therapy. Our systematic review and meta-analysis indicated that BoNT could be beneficial for short-term symptom improvement in patients with DD, but this effect tended to decline 12 months after injection. Standardized BoNT intervention protocols remain warranted. Among the several treatments for DD, we concluded that BoNT injection is not inferior to other options considering its effectiveness in relieving symptoms, the associated complication development, and the risk of symptom recurrence.

Botulinum toxin type A for the treatment of dyssynergic defaecation in adults: a systematic review

AIM

Dyssynergic defaecation (DD) is characterized by inappropriate coordination of the pelvic floor muscles during defaecation, resulting in impaired stool expulsion. The mainstay of treatment is biofeedback and alternative therapies are limited in those who do not respond. This systematic review evaluated botulinum toxin type A injection (BTXA) as a treatment option for dyssynergia.

METHODS

PubMed, Embase and Cochrane Central Register of Controlled Trials were searched for studies evaluating adult patients with DD treated with BTXA injection into the puborectalis and/or external anal sphincter. All study designs, except case reports, were included in the review with no language restriction. Studies limited to patients with specific neurological diagnoses or with a follow-up period under 1 month were excluded. Study selection, assessment and data extraction were performed by two reviewers and results were synthesized narratively.

RESULTS

Eleven studies (three randomized control trials) involving 248 participants were included. All studies used the transanal approach to deliver the injection, most commonly at the 3 and 9 o'clock positions using digital palpation for guidance. The most commonly used patient position was left lateral, and most studies did not use any anaesthesia. The dose of BTXA varied (Botox 12-100 units, Dysport 100-500 units), and outcomes measured were heterogeneous (global rating ± up to five investigations). Symptomatic improvement varied between 29.2% and 100% and adverse effects occurred in 0% to 70%.

CONCLUSION

The evidence to support using BTXA for DD is poor and only covers a transanal approach. Future studies should redress these limitations: heterogeneity of design, dose and outcome measures.

S3-Leitlinie: Analfissur

Die Analfissur ist eine der häufigsten Pathologien, welche sich dem Proktologen präsentiert. Entsprechend ist es wichtig, verlässliche Leitlinien dazu zu entwickeln. Die aktuelle Leitlinie wurde anhand eines systematischen Literaturreview von einem interdisziplinären Expertengremium diskutiert und verabschiedet.

Die akute Analfissur, soll auf Grund ihrer hohen Selbstheilungstendenz konservativ behandelt werden. Die Heilung wird am besten durch die Einnahme von Ballaststoff reicher Ernährung und einer medikamentösen Relaxation durch Kalziumkanal-Antagonisten (CCA) unterstützt. Zur Behandlung der chronischen Analfissur (CAF), soll den Patienten eine medikamentöse Behandlung zur „chemischen Sphinkterotomie“ mittels topischer CCA oder Nitraten angeboten werden. Bei Versagen dieser Therapie, kann zur Relaxation des inneren Analsphinkters Botulinumtoxin injiziert werden. Es ist belegt, dass die operativen Therapien effektiver sind. Deshalb kann eine Operation schon als primäre Therapie oder nach erfolgloser medikamentöser Therapie erfolgen. Die Fissurektomie, evtl. mit zusätzlicher Botulinumtoxin Injektion oder Lappendeckung, ist die Operation der Wahl. Obwohl die laterale Internus Sphinkterotomie die CAF effektiver heilt, bleibt diese wegen dem höheren Risiko für eine postoperative Stuhlinkontinenz eine Option für Einzelfälle.

Gastrointestinal Uses of Botulinum Toxin

Botulinum toxin (BT), one of the most powerful inhibitors that prevents the release of acetylcholine from nerve endings, represents an alternative therapeutic approach for "spastic" disorders of the gastrointestinal tract such as achalasia, gastroparesis, sphincter of Oddi dysfunction, chronic anal fissures, and pelvic floor dyssynergia.BT has proven to be safe and this allows it to be a valid alternative in patients at high risk of invasive procedures but long-term efficacy in many disorders has not been observed, primarily due to its relatively short duration of action. Administration of BT has a low rate of adverse reactions and complications. However, not all patients respond to BT therapy, and large randomized controlled trials are lacking for many conditions commonly treated with BT.The local injection of BT in some conditions becomes a useful tool to decide to switch to more invasive therapies. Since 1980, the toxin has rapidly transformed from lethal poison to a safe therapeutic agent, with a significant impact on the quality of life.

Treatment of gastrointestinal sphincters spasms with botulinum toxin A

Botulinum toxin A inhibits neuromuscular transmission. It has become a drug with many indications. The range of clinical applications has grown to encompass several neurological and non-neurological conditions. One of the most recent achievements in the field is the observation that botulinum toxin A provides benefit in diseases of the gastrointestinal tract. Although toxin blocks cholinergic nerve endings in the autonomic nervous system, it has also been shown that it does not block non-adrenergic non-cholinergic responses mediated by nitric oxide. This has promoted further interest in using botulinum toxin A as a treatment for overactive smooth muscles and sphincters. The introduction of this therapy has made the treatment of several clinical conditions easier, in the outpatient setting, at a lower cost and without permanent complications. This review presents current data on the use of botulinum toxin A in the treatment of pathological conditions of the gastrointestinal tract.

Identifying the best therapy for chronic anal fissure

Chronic anal fissure (CAF) is a painful tear or crack which occurs in the anoderm. The optimal algorithm of therapy for CAF is still debated. Lateral internal sphincterotomy (LIS) is a surgical treatment, considered as the ‘gold standard’ therapy for CAF. It relieves CAF symptoms with a high rate of healing. Chemical sphincterotomy (CS) with nitrates, calcium blockers or botulinum toxin (BTX) is safe, with the rapid relief of pain, mild side-effects and no risk of surgery or anesthesia, but is a statistically less effective therapy for CAF than LIS. This article considers if aggressive treatment should only be offered to patients who fail pharmacological sphincterotomy. Aspects of anal fissure etiology, epidemiology and pathophysiology are considered with their meaning for further management of CAF. A molecular model of chemical interdependence significant for the chemistry of CAF healing is examined. Its application may influence the development of optimal therapy for CAF. BTX is currently considered the most effective type of CS and discussion in this article scrutinizes this method specifically. Although the effectiveness of BTX vs. LIS has been discussed, the essential focus of the article concerns identifying the best therapy application for anal fissure. Elements are presented which may help us to predict CAF healing. They provide rationale for the expansion of the CAF therapy algorithm. Ethical and economic factors are also considered in brief. As long as the patient is willing to accept the potential risk of fecal incontinence, we have grounds for the ‘gold standard’ (LIS) as the first-line treatment for CAF. We conclude that, when the diagnosis of the anal fissure is established, CS should be considered for both ethical and economic reasons. The author is convinced that a greater understanding and recognition of benign anal disorders by the GP and a proactive involvement at the point of initial diagnosis would facilitate the consideration of CS at an earlier, more practical stage with improved outcomes for the patient.

Comparative study between botulinum toxin injection and partial division of puborectalis for treating anismus

OBJECTIVES

The objective of this study was to compare the results of partial division of puborectalis (PDPR) versus local botulinum toxin type A (BTX-A) injection in treating patients with anismus.

PATIENTS AND METHODS

This prospective randomized study included 30 male patients suffering from anismus. Diagnosis was made by clinical examination, barium enema, colonoscopy, colonic transit time, anorectal manometry, balloon expulsion test, defecography, and electromyography. Patients were randomized into: group I which included 15 patients who were injected with BTX-A and group II which included 15 patients who underwent bilateral PDPR. Follow-up was conducted for about 1 year. Improvement was considered when patients returned to their normal habits.

RESULTS

BTX-A injection achieved initial success in 13 patients (86.7%). However, long-term success persisted only in six patients (40%). This was in contrast to PDPR which achieved initial success in all patients (100%) with a long-term success in ten patients (66.6%). Recurrence was observed in seven patients (53.8%) and five patients (33.4%) following BTX-A injection and PDPR, respectively. Minor degrees of incontinence were confronted in two patients (13.3%) following PDPR.

CONCLUSION

BTX-A injection seems to be successful for temporary treatment of anismus.

Botulinum toxin A for the treatment of chronic anal fissure

Since its introduction for the treatment of strabismus, botulinum toxin (BoNT) has been increasingly used in the treatment of several disorders with excessive or inappropriate muscle contractions. The therapeutic effects of BoNT occur through the temporary chemodenervation caused by the injection into the local target muscle or skin. Modulation of muscle relaxation may be achieved by varying the dose of BoNT solution injected; most adverse effects are transient. Indeed, botulinum neurotoxin has been used to selectively weaken the internal anal sphincter as a treatment for chronic anal fissure in several randomized, controlled trials and open-label studies. The use of botulinum neurotoxin seems to be an effective and safe approach for the treatment of chronic anal fissure, particularly in patients at high risk for incontinence.

Why the most potent toxin may heal anal fissure

An anal fissure is a painful linear ulcer in the lower part of the anal canal. It is very often referred to as an ischemic ulcer. Anodermal blood flow is negatively correlated with resting pressure of the anus. Increased activity of the internal anal sphincter may decrease the anodermal blood supply by compressing arterioles. Surgical procedures and botulinum treatment for patients with chronic anal fissure produce a temporary reduction in anal pressure, reverse sphincter spasm, and promote fissure healing. However, recent studies have shown that fissure healing does not appear to be dependent on reduction in mean resting anal pressure. On the basis of the published literature, this article attempts to explain this phenomenon in detail. The mechanism of action of botulinum toxin on the internal anal sphincter is not yet fully understood. This review focuses on problems associated with anal fissure treatment and presents them from the wider angle of science about botulinum toxin. In our opinion, anodermal blood flow depends not only on the "mechanical" force of sphincters but also on biochemical processes that occur in the fissure region.

Toxine botulique et fissure anale chronique

Lateral internal sphincterotomy is widely used in the treatment of chronic anal fissure. However, it is associated with a high rate of irreversible incontinence. For this reason the botulinum toxin has become a medical means of reversible sphincterotomy. Indeed, this neurotoxin induces relaxation of the smooth internal anal sphincter lasting one to three months after one injection. We reviewed the published studies about the use of this technique in the management of chronic anal fissure. Healing occurred in more than 70% of fissures without irreversible incontinence. Although further studies are needed to determine the best modalities of administration, especially due to the remaining significant recurrence rate, this toxin may be a valuable treatment for chronic anal fissure in the future.

Novel delivery of botulinum toxin for the treatment of anal fissures

OBJECTIVE

Botulinum toxin A (Botox) has been used as a local treatment for anal fissure since 1994. It effects a reversible chemical sphincterotomy without the need for patient compliance. This study examines the feasibility of injecting the treatment using a needle-less system.

PATIENTS AND METHODS

The optimal angle for injection was determined in a preclinical study using fresh porcine specimens. Ten patients with chronic anal fissures were then injected with 20 units Botox at the site of the fissure. They underwent assessment with a visual analogue pain scale, incontinence score and anal manometry pre-injection, at 48 h postinjection and at six and 12 weeks postinjection. They were also examined at the initial and final visits.

RESULTS

The optimal angle for injection was 60 degrees . All 10 patients (5 male; median age 40.5 years (range 26-68 years)) attended the 48 h follow up visit but only seven attended the six and 12 week visits. Six of seven patients healed their fissures. The remaining three were contacted by telephone at six months post injection and two of three remained asymptomatic without further treatment. In seven patients who underwent full follow up the median pain score pre-injection was 5.5 out of 10 (range 1-10) and this dropped to a median of 1 (range 0-6) at 12 weeks. The median drop in resting pressure was 47 cm H2O or 37% at six weeks.

CONCLUSION

No needle injection of Botox is feasible with similar healing rates and reduction of resting pressure to conventional injection techniques.

Botulinum toxin type A injections: Adverse events reported to the US Food and Drug Administration in therapeutic and cosmetic cases

BACKGROUND

Botulinum toxin type A (BTA) (Botox) received Food and Drug Administration (FDA) approval for therapeutic treatment of strabismus and blepharospasm in 1989, cervical dystonia in 2000, and cosmetic treatment of glabellar wrinkles (Botox Cosmetic) in 2002. In 2002 alone there were approximately 1.1 to 1.6 million patients using cosmetic BTA. Our objective was to review adverse event (AE) reporting to the FDA after BTA administration.

METHODS

We reviewed all (therapeutic and cosmetic use) serious (per FDA regulations) AEs reported to the FDA for the 13.5 years since licensure of the product (December 1989-May 2003) and nonserious AEs reported from December 2001 to November 2002. AEs are reported to the FDA through the MedWatch system.

RESULTS

We reviewed 1437 AE reports; 406 followed therapeutic use of BTA (217 serious and 189 nonserious) and 1031 followed cosmetic use (36 serious and 995 nonserious). Reported AEs occurred predominantly in female patients, with a median age of 50 years. In the year December 2001 to November 2002, when both serious and nonserious reports were evaluated, the proportion of reports classified as serious was 33-fold higher for therapeutic than for cosmetic cases. The 217 serious AEs reported in therapeutic cases involved a wide spectrum of events and included all 28 reported deaths. Among cosmetic users, no deaths were reported and, of the 36 serious AEs, 30 were included as possible complications in the FDA-approved label. The remaining 6 serious AEs did not display a pattern suggesting a common causal relationship to BTA. Among the 995 cosmetic cases reported to have nonserious AEs, most commonly noted were lack of effect (623, 63%), injection site reaction (190, 19%), and ptosis (111, 11%).

CONCLUSIONS

Serious AEs were more likely to be reported for therapeutic than for cosmetic use, which may be related to higher doses, complicated underlying diseases, or both. Among cosmetic cases, few serious AEs were reported, and these were predominantly events that were previously recognized in clinical trials of BTA for the labeled use. This study is limited primarily by the incomplete nature of AE reporting by clinicians. Numerous departures from FDA-approved recommendations for drug dose, dilution, handling, site of injection, and storage were noted in these AE reports.

[Botulinum toxin and medical liability: is the patient sufficiently informed?]

INTRODUCTION

The use of botulinum toxin injection therapy is soaring significantly today, with an ever-wider field of applications despite well-known side effects of the treatment. This article aims at analysing the medicolegal practices of practitioners who use this therapy, especially the information given to patients and finding a common practice for providing that information.

METHODS

We sent a questionnaire to 340 practitioners who might use the therapy (physiatrists, neurologists, ophthalmologists, ENT specialists, plastic surgeons) working in hospitals and in physical therapy and rehabilitation centres in France. Besides mentioning the possible side effects of the therapy, the questionnaire focused on how such information was transmitted before the injection.

RESULTS

Data collection and analysis were performed by use of a spreadsheet software programme. A total of 124 questionnaires were analysed. We did not analyse the items dealing with side effects. Sixty-five percent of the responders said they did not seek statutory authorisation for injections. Only 31% provided written, detailed information and 12% required a signed consent form. Complaints were rare, approximately 12%, were written or verbal, and were always dismissed.

DISCUSSION

Side effects after botulinum toxin injection are clearly described in the medical literature. Therefore, it is of utmost importance for this product to be used therapeutically and only by experienced therapists who will carefully respect the product's standard rules of use and inform their patients to the best of their ability. Issuing a detailed letter of information describing all the side effects seems necessary. We suggest a model information letter such as that provided to the patients in our facility.

CONCLUSION

Botulinum toxin is a very worthwhile product for numerous abnormalities but has side effects, often brief, at the site of the injection. Therefore it is our duty to inform patients effectively.

Treating chronic anal fissure with botulinum neurotoxin

Recent reports confirm that the management of chronic anal fissure has undergone extensive re-evaluation during the past few years. This rejuvenation of interest is attributable to the application of neurochemical treatment, which has contributed to the tendency to treat the disease on an outpatient basis. The use of botulinum neurotoxin seems to be a promising and safe approach for the treatment of chronic anal fissure, particularly in patients at high risk for incontinence. Indeed, botulinum neurotoxin has been successfully used selectively to weaken the internal anal sphincter as a treatment for chronic anal fissure. It is also more efficacious than nitrate therapy, and is not related to the patient's willingness to complete treatment.

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.