Efficacy of Botulinum Toxin in Treating Pain on Chronic Anal Fissure

• Autor(a) principal: Prado Costa, Rui; Serviço de Medicina Física e de Reabilitação do Centro Hospitalar Universitário de São João, Porto, Portugal
• Data de Publicação: 2021
• Outros Autores: Tavares, Helena; Serviço de Medicina Física e de Reabilitação do Centro Hospitalar Universitário de São João, Porto, Portugal, Oliveira, Mafalda; Serviço de Medicina Física e de Reabilitação do Centro Hospitalar Universitário de São João, Porto, Portugal, Barbosa, Paula; Unidade de Dor Crónica do Centro Hospitalar Universitário de São João, Porto, Portugal, Gomes, Armanda; Unidade de Dor Crónica do Centro Hospitalar Universitário de São João, Porto, Portugal, Festas, Maria José; Serviço de Medicina Física e de Reabilitação do Centro Hospitalar Universitário de São João, Porto, Portugal
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: https://doi.org/10.25759/spmfr.382
• topic: Botulinum Toxins; Fissure in Ano/drug therapy; Pain; Dor; Fissura Anal/tratamento farmacológico; Toxinas Botulínicas

Introduction: Chronic anal fissure (FAC) is a condition associated with high pain and decrease in quality of life. The hypertonia of internal anal sphincter (EAI) is the main etiologic factor implicated in FAC and the spasm-pain-spasm cycle perpetuates this mechanism. Injection of Botulinum toxin (BoNT) in EAI promotes, through transitory chemical denervation, muscle relaxation and antinoceptive effects, thereby interrupting the physiopathological cycle and consequently providing conditions for fissure resolution.Material and Methods: Retrospective study including 159 patients from January 2009 to September 2019, refereed to a Chronic Pain Unit from a Hospital Center, with diagnosis of chronic anal fissure not responding to conservative treatment. Those patients were submitted to injection of 40U of onabotulinumtoxinA in EAI. Clinical records were used to collect pain scores during and after defecation (obtained with numeric rating pain scale) in pre- and post- treatment (the latter at 1 month assessment after injection), the occurred side effects and the necessity of new injection or surgical treatment.Results: Hundred fifty nine patients in which 59.1 % were female, mean age of 51.1±14.4 years old. Pain during defecation was 7.3±2.5 and after defecation was 5.3±2.8. Pain intensity significantly reduced after injection of BoNT (p<0.001) with a magnitude of 4.4±3.1 and 3.4±2.8 during and after defecation respectively. About 31.8% of patients reported a complete resolution of pain and 14.5% maintained the same level of pain intensity. Repeated injection of BoNT was necessary in 5.0% patients in a year, 4.5 % after an year for pain control. Were submitted to surgical treatment, 19,7% due to refractoriness to treatment. Non severe side effect occurred in 16 patients. Age (p=0.267) and gender (p=0.4238) had no statistic association to treatment response.Conclusion: Treatment of pain with BoNT in FAC refractory to conservative treatment was effective and secure and therefore surgical treatment may be reserved for patients refractory to this treatment. However, refractoriness with this treatment are not negligible and predictive factors of unsuccess are still undetermined.