Clinical Outcomes of Botulinum Toxin Injection in Anal Fissures with Normal Resting Sphincter Pressure: A Targeted Approach

Abstract

Chronic anal fissures (CAF) are a common yet debilitating condition, often associated with increased resting sphincter pressure. These fissures lead to significant pain, bleeding, and impaired quality of life for the affected individuals. Standard treatments, including topical agents and lateral internal sphincterotomy (LIS), are frequently employed to manage this condition. However, patients presenting with normal resting anal sphincter pressures (NRP) pose a clinical challenge. Surgical options such as LIS carry risks of incontinence, which are unacceptable for many patients, especially those with normal sphincter function. In this study, we explore the clinical outcomes of Botulinum toxin type A (BoNT-A) injections for the treatment of chronic anal fissures in patients with normal resting sphincter pressures. BoNT-A has shown promising results in patients with increased sphincter tone, and this study aims to evaluate its role in normotonic cases.

A prospective observational study was conducted at a tertiary care institution over a period of 18 months. Forty patients with chronic anal fissures and normal resting sphincter pressure were selected for BoNT-A treatment. Outcomes assessed included pain relief (measured by Visual Analog Scale (VAS)), healing rates (observed clinically and via proctoscopy), changes in resting anal pressures, and continence outcomes using the Wexner incontinence score. The results demonstrated that BoNT-A provided effective pain relief and healing in 80% of patients without significant changes in resting sphincter pressure, thus offering a sphincter-preserving alternative to surgery. Furthermore, no significant issues with continence were observed in the majority of patients. This study suggests that BoNT-A is a promising treatment option for chronic anal fissures with normal resting sphincter pressures, providing a valuable non-surgical approach.