Ilioinguinal iliohypogastric nerve blocks--before or after cesarean delivery under spinal anesthesia?

Preoperative local anesthetic blockade of somatosensory pathways involved with skin incision and other noxious perioperative stimuli may "preempt" or attenuate the postoperative pain response. Since the Pfannenstiel incision lies within the L1 dermatome, bilateral ilioinguinal, iliohypogastric nerve blocks (IINBs) should provide analgesia after low transverse cesarean section. We designed this study to compare the analgesic effect of IINBs placed before or after cesarean delivery. Forty-six patients undergoing cesarean delivery with spinal anesthesia were enrolled. Patients were randomly assigned to one of three groups: Before, After, or None. Bilateral IINBs were placed with 0.5% bupivacaine, 10 mL to each side. Twenty-two patients had IINBs placed before surgery (11 failed blocks), 12 had blocks placed after surgery, and 12 had no block. Morphine, through a patient-controlled analgesia (PCA) pump, provided additional postoperative analgesia. A blinded observer assessed 24-h morphine use as well as patient satisfaction and pain scores ("incisional" and "overall") for 96 h. Although there were no consistent differences in pain scores among the groups, patients in the After group occasionally reported more pain than those in the Before and None groups. Patient satisfaction and morphine use did not differ among the groups. We conclude that there is no benefit to ilioinguinal nerve blocks, either before or after surgery, in patients who receive spinal anesthesia for elective cesarean delivery. Our finding of increased pain in the After group is perplexing and requires confirmation.