Patient Position: Supine.

Indications: Differential nerve block for groin pain, ilioinguinal neuralgia, and post-herniorrhaphy pain.

Needle Size: 22-gauge, 50-mm insulated needle.

Medication/Volume: 0.25% bupivacaine 5 to 7 mL and 40 mg Depo-Medrol (Pharmacia Canada, Inc., Hamilton, Ontario, Canada), for a total of 8 mL.

Anatomic Landmarks: The most medial part of the anterior superior iliac spine (ASIS).

Approach and Technique: For the ilioinguinal nerve block, with the patient in supine position, palpate the most medial part of the ASIS. Mark a point 1 cm medial and 1 cm caudal to the most medial part of the ASIS.

For the iliohypogastric nerve block, the point of needle insertion is 1 cm medial and 1 cm cephalad to the most medial part of the ASIS (Fig. 72-1).

For both procedures, the area is prepared with Betadine (Purdue Pharma L.P., Stamford, CT). Next, a 50-mm insulated needle attached to a 10-mL syringe and a nerve stimulator is introduced through the skin. The nerve stimulator is set up to deliver 1.5 mA. The needle is advanced with continuous aspiration in an oblique angle toward the pubic symphysis. Once paresthesia is elicited, the needle position is adjusted to maintain the paresthesia with a current of 0.4 mA. After negative aspiration for blood, the local anesthetic mixture is slowly injected. The needle is then removed, and pressure is applied to reduce the risk of postblock ecchymosis and hematoma.