Comparative Study Between Caudal and Perianal Block on Intraoperative Anal Sphincter Muscle Tone and Postoperative Analgesia During Anal Sphincter Sparing Procedures Under General Anesthesia

Anal fistula is an abnormal tract communicating an external opening in the perianal skin with an internal opening in the anal canal. Anal fistula is treated by fistulotomy . sphincter sparing procedures are usually done under general anesthesia omitting neuromuscular blocking agents in order to preserve sphincter tone intraoperatively.

The study will be designed to recruit 46 patients who have complex anal fistula and will be scheduled for sphincter sparing surgery.

All patients will receive routine preanesthetic evaluation. They will be kept fasting for2 hours for clear fluids and at least 8 hours for solid food prior to performing the block. On arrival in the operating room, heart rate (HR), non invasive blood pressure, oxygen saturation (SPO2) and electrocardiography monitors will be applied and the baseline values will be noted. Intravenous access (IV) will be secured and an appropriate IV fluid will be started.

Patients will receive general anesthesia with induction of 2mg/kg IV propofol, 1mcg/kg IV fentanyl and laryngeal mask insertion in supine positionand maintenance of anesthesia with isoflurane inhalation.

Patients will be randomly allocated into two study groups;