Comparing Ilioinguinal Single-shot and Three-layer Blocks

Ilio-inguinal nerve blocks have a long history of efficacy in treatment of post-operative pain following inguinal surgery. Several anatomic studies have shown that the nerves supplying the inguinal area have a certain degree of variability with respect to their location between the internal and external oblique layers of the anterior abdominal wall. Furthermore, the standard single-shot approach to ilio-inguinal nerve blocks has a significant incidence of unintended femoral nerve block, which can impair patients' ability to walk after surgery. The investigators are proposing a new approach to the ilio-inguinal nerve block, which divides the total dose of local anesthetic into 3 equal parts, injecting each 1/3 into different layers of the anterior abdominal wall and sub-cutaneously. The investigators intend to show that this new technique, the Tsui approach, provides equal analgesia to the standard single-shot ultrasound-guided ilio-inguinal nerve block, while being faster to perform and having a lower incidence of unintended femoral nerve blockade. Patients under age 10 who are scheduled for elective inguinal surgery (hydrocele repair, orchidopexy, and inguinal hernia repair), who have already consented to an ilio-inguinal nerve block that is commonly placed for this type of procedure, will be approached to participate in this study. No increased risk is anticipated for these patients, as both ultrasound-guided and blind techniques are equally well-accepted in the literature for this type of block, and in addition there are few vascular or neural structures in this anatomical area (just medial and inferior to the anterior superior iliac spine) that may be damaged. Follow-up will be limited to an assessment of pain scores in the PACU post-operatively and any unintended femoral nerve blockade in post-PACU. This will not delay their hospital discharge as these are same-day surgery patients.