Bilateral versus Posterior Injection of Botulinum Toxin in the Internal Anal Sphincter for the Treatment of Acute Anal Fissure

摘要

Aim: Comparison of bilateral versus posterior injection of botulinum toxin in the internal anal sphincter for treatment of acute anal fissure and prevention of chronicity.Methods: Forty patients with acute anal fissure were randomly divided into two equal groups. Group I patients were treated by injecting 20 units of Botulinum toxin on each lateral side of the internal anal sphincter. Group II patients were treated by injecting 25 units of Botulinum toxin in the midline posteriorly.Results: Mean period for pain relief was 8.45±7.41 days in group I and 7.20±7.19 days in group II. Mean time of healing was 5.20 ±1.85 weeks in group I and 5.40 ±2.01 weeks in group II. Two patients (10%) in group I and 3 patients (15%) in group II showed no healing. Fissure recurred to 4 patients (20%) in group I and 3 patients (15%) in group II.Conclusion: Botulinum toxin injection is effective in treating acute anal fissure and preventing chronicity. A single posterior injection is easier, less painful and as effective as bilateral injection in pain relief. Introduction Anal fissure is a common, painful condition that causes significant morbidity mostly in young adults. It is a split in the skin of the distal anal canal. The classic symptoms are intense pain on or after defecation and anal bleeding [1]. Anal fissures are nearly always single, and they have predilection for the posterior midline location and less commonly for the anterior midline where one of ten fissures is located [2].Anal fissure is clinically differentiated into acute and chronic. The point at which an acute fissure becomes chronic is contentious, but published work suggests symptoms lasting for more than two months are undeniably chronic [3].Most anal fissures are caused by stretching of the anal mucosa beyond its capability. Many acute anal fissures will heal spontaneously or by medical treatment. Recurrence rates range from 30-70% if treatment is abandoned after the fissure is healed [4]. Some fissures become chronic and will not heal. The most common cause for this is spasm of the internal anal sphincter muscle. This spasm causes poor blood flow to the anal mucosa, hence producing an ulcer which does not heal since it is deprived of normal blood supply [5].Aggressive treatment of acute anal fissure with the recently named chemical sphincterotomy may prevent its evolution to chronicity.The aim of this study is to evaluate the efficacy of injection of Botulinum toxin into the internal anal sphincter for treatment of acute anal fissure and prevention of chronicity and to compare two sites of injection of Botulinum toxin; bilateral versus posterior. Patients And Methods This study was performed in the General Surgery Department, Ghodran General Hospital, KSA, during the period from October 2005 to February 2008 on 40 patients with acute posterior anal fissure randomly divided through computer randomization program (www.randomization.com) into two equal groups. Patients having other anal pathology (i.e., inflammatory bowel diseases, hemorrhoids, anal fistula or anal abscess) were excluded from this study. Full explanation of procedures and patient consent were assured before inclusion in the research. The study protocol was approved by the Ethics Committee of Ghodran General Hospital, KSA.Group I patients were treated by injection of Botulinum toxin into the internal sphincter. The 100 units’ vials of type A lyophilized Botulinum toxin (Botox, Allergan, Inc, Irvine, CA, USA) were diluted in saline to a concentration of 50 units per milliliter immediately before injection. With a 25-G needle, 20 units were injected on each side of the internal sphincter guided under direct vision and digital examination (a total of 40 units per patient). No sedation or local anesthesia was used during the procedure.Group II patients were treated by a single injection of 25 units of Botulinum toxin with a 25-G needle into the internal sphincter in the midline posteriorly under direct vision and d