Impact of sentinel pile on botulinum toxin treatment of chronic anal fissure: A comparative study

AIM: The aim of this study was to investigate if the presence of a prominent sentinel pile (SP) had any impact on the treatment success of botulinum toxin (BT) injection, as well as the clinical presentation of patients with chronic anal fissure (CAF). METHODS: Patients with CAF with or without prominent sentinel piles underwent BT injection. In addition to objective healing, a detailed symptom severity score (REALISE) immediately before and 6 months after BT injection was recorded. This was a retrospective, single-center observational cohort study including consecutive patients treated in a specialized proctology unit. RESULTS: Of the 249 patients, 68 presented with prominent SP (27.3%). The overall objective healing rate among all patients who received a single injection of BT was found to be 74.7% at 2 months. When stratified, age distribution was similar between patients with (SP+) and without SP (SP-) (p = 0.545). However, SP was more prevalent in female patients (p = 0.009). The objective healing rates after a single BT injection were 80.7% in the SP- group and 58.8% in the SP+ group (p = 0.001). Pre-treatment REALISE scores were significantly reduced in both groups after BT injection (p < 0.001 for both). However, post-treatment scores were higher in the SP+ group compared with the SP- group (p < 0.001). Multivariable analysis confirmed SP presence as an independent predictor of reduced objective healing after BT injection. CONCLUSIONS: Even with the SP, a considerable proportion of patients with CAF heal after BT treatment and their symptoms are generally relieved. However, symptomatic improvement is less marked and the objective healing rates are lower in the SP+ group. The presence of SP may, therefore, negatively influence the clinical effectiveness of BT treatment of CAF. These findings should be interpreted in light of the retrospective single-center design and the potential for selection and recall bias.