Effects of Dexmedetomidine as Adjunct to Pudendal Block for Pediatric Penile Surgery

Caudal block is often performed to relieve postoperative pain in pediatric urological surgery. Recently, pudendal block is also used in penile surgery and it has advantage because of less side effects such as transient weakness of low extremities, but limited to use in penile surgery. Local anesthesia is a single shot injection, so additional analgesic drugs is required when the effect of local anesthetics are disappeared. Dexmedetomidine, an alpha adrenergic agonist, is commonly used in pediatric sedation. It has analgesic effect and potentiates the effect of local anesthetics. There are many studies about the potentiation of the effect of local anesthetics when added to dexmedetomidine in adults, it has been limited in pediatrics. Recent study said that local anesthetics with dexmedetomidine had prolonged duration of analgesia in caudal block, also in ilioinguinal block. Thus it is expected to have a prolonged effect when investigators use dexmedetomidine in pediatrics as well as adults.

Elective Penile Surgeries, Hypospadias, Urethral Fistula or Stricture After Hypospadias Repair, Penile Curvature

Patients are put in lithotomy position. Two separate injection points are marked at 3 and 9 o'clock, about 2 to 2.5 cm from the center of anus. After aseptic preparation, a nerve stimulator needle advanced 1.5 to 3.5 cm perpendicular to the skin, and stimulation current is 2.5 to 5 mA. The unilateral contraction of anal sphincter means the inferior anal nerve stimulation. After reducing the current to 0.5 mA, the needle is then moved deeper until an up-and-down penile movement is observed. This is stimulation of the perineal branch of the pudendal nerve. Prepared drug (0.25% ropivacaine and 0.3 mcg/kg dexmedetomidine in the experimental group, and equivalent doses of ropivacaine and normal saline in the control group) is injected in half and half bilaterally.

time to first rescue medication, assessed up to 24 h (time frame: from the administration of the pudendal block to the first registration of a FLACC≥4) (FLACC: face, legs, activity, cry, consolability)

The time of arrival in the recovery room, 10, 20, 30 min after arrival of the recovery room, and 4, 8, 12, 24 h after the surgery.

The time of arrival in the recovery room, 10, 20, 30 min after arrival of the recovery room, and through the time of discharge from the PACU, an average of 30 minutes

Inclusion Criteria: The patients aged between 6 months and 6 years in elective penile surgeries (hypospadias, urethral fistula or stricture after hypospadias repair, penile curvature) American Society of Anesthesiologists (ASA) class I, II Exclusion Criteria: Coagulopathy allergy to local anesthetics meatal island onlay proximal transverse island flap (MIOPTI) (more than 4 h for the surgery) illiteracy, foreigner

Department of Anaesthesiology and Pain Medicine, Anaesthesia and Pain Research Institute, Yonsei University College of Medicine