Efficacy of caudal block on postoperative analgesia during anal sphincter-sparing procedures under general anesthesia

Background Fistulotomy performed for a complex anal fistula carries a high risk of injury to the anal sphincter which can lead to incontinence. Therefore, many surgeons prefer to preserve muscle tone during this surgery. This study aims to compare the effect of caudal epidural block analgesia versus opioid analgesia for complex anal fistula surgeries. Patients and methods This is a randomized, controlled, double-blinded trial conducted in the uni-centre teaching hospital. Adult patients aged 18–60 years, American Society of Anesthesiologists physical status I–II, with complex anal fistula were included in this study. Patients were divided into two groups: the caudal group ( n =17) and the control group ( n =13). The primary outcome of this study was the time to first request rescue postoperative analgesia Results The mean time to first request of rescue postoperative analgesia was longer in the caudal group compared with the control group (18.5±5.5 vs. 1.7±2.45 h; P <0.001. The caudal group had lower total consumption of intraoperative fentanyl and postoperative morphine consumption compared with the control group. The time for first ambulation, time for first urination, and Digital Rectal Examination Scoring System score were comparable between the two study groups. Conclusions In complex anal fistula surgery, supplementing general anesthesia with caudal block provides better pain control and less incidence of nausea and vomiting than standard care, without affecting the anal tone.