title: The effect of local injections of bupivacaine plus ketamine, bupivacaine alone, and placebo on reducing postoperative anal fistula pain: a randomized clinical trial.
abstract: OBJECTIVE
  This study aimed to compare the effects of different local anesthetic solutions on postoperative pain of anal surgery in adult patients.
  
  
  METHODS
  In this randomized double-blind prospective clinical trial, 60 adult patients (18 to 60 years old) with physical status class I and class II that had been brought to a university hospital operating room for fistula anal surgery with spinal anesthesia were selected. Patients were randomly divided into 4 equal groups according to table of random numbers (created by Random Allocation Software 1). Group 1 received 3 mL of normal saline, group 2, 1 mL of normal saline plus 2 mL of bupivacaine 0.5%, group 3, 1 mL of ketamine plus 2 mL of bupivacaine 0.5%, and group 4, no infiltration. Intensity of pain in patients was measured using visual analogue scale (VAS) at 0 (transfer to ward), 2, 6, 12, and 24 hours after surgery. Time interval to administration of drugs and overall dose of drugs were measured in 4 groups.
  
  
  RESULTS
  Mean level of pain was the lowest in group 3 at all occasions with a significant difference, followed by groups 2, 4, and lastly 1 (P < 0.001). Furthermore, groups 2 and 3 compared to groups 1 and 4 had the least overall dose of analgesics and requested them the latest, with a significant difference (P < 0.05).
  
  
  CONCLUSIONS
  Local anesthesia (1 mL of ketamine plus 2 mL of bupivacaine 0.5% or 1 mL of normal saline plus 2 mL of bupivacaine 0.5%) combined with spinal anesthesia reduces postoperative pain and leads to greater comfort in recovering patients.
authors.affiliation: Department of General Surgery, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Kazemeini
authors.affiliation: Department of Anesthesiology, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mojgan
authors.initials: M
authors.lastname: Rahimi
authors.affiliation: Department of Anesthesiology, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Sadegh
authors.initials: MS
authors.lastname: Fazeli
authors.affiliation: Brain and Spinal Injury Research Center (BASIR), Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Seyedeh Adeleh
authors.initials: SA
authors.lastname: Mirjafari
authors.affiliation: Department of Cardiovascular Surgery, Shahid Modarres Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Hamid
authors.initials: H
authors.lastname: Ghaderi
authors.affiliation: Department of Anesthesiology, Shahid Modarres Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Kamal
authors.initials: K
authors.lastname: Fani
authors.affiliation: Department of Anesthesiology, Semnan Medical University, Semnan, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Forozeshfard
authors.affiliation: Brain and Spinal Injury Research Center (BASIR), Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Marzieh
authors.initials: M
authors.lastname: Matin
mesh_terms: D000328:Adult; D000778:Anesthetics, Dissociative / Q000008:administration & dosage*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D002045:Bupivacaine / Q000008:administration & dosage*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007649:Ketamine / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D059408:Pain Management; D010147:Pain Measurement; D010149:Postoperative Pain / Q000188:drug therapy* / Q000209:etiology; D011446:Prospective Studies; D012003:Rectal Fistula / Q000601:surgery*
chemical_list: D000778:Anesthetics, Dissociative; D000779:Anesthetics, Local; D007649:Ketamine; D002045:Bupivacaine