Ultrasonography for ilioinguinal/iliohypogastric nerve blocks in children

The ilioinguinal/iliohypogastric nerve block is a popular regional anaesthetic technique for children undergoing inguinal surgery. The success rate is only 70-80% and complications may occur. A prospective randomized double-blinded study was designed to compare the use of ultrasonography with the conventional ilioinguinal/iliohypogastric nerve block technique.

One hundred children (age range, 1 month-8 years) scheduled for inguinal hernia repair, orchidopexy or hydrocele repair were included in the study. Following induction of general anaesthesia, the children received an ilioinguinal/iliohypogastric block performed either under ultrasound guidance using levobupivacaine 0.25% until both nerves were surrounded by the local anaesthetic or by the conventional 'fascial click' method using levobupivacaine 0.25% (0.3 ml kg(-1)). Additional intra- and postoperative analgesic requirements were recorded.

Ultrasonographic visualization of the ilioinguinal/iliohypogastric nerves was possible in all cases. The amount of local anaesthetic used in the ultrasound group was significantly lower than in the 'fascial click' group (0.19 (SD 0.05) ml kg(-1) vs 0.3 ml kg(-1), P<0.0001). During the intraoperative period 4% of the children in the ultrasound group received additional analgesics compared with 26% in the fascial click group (P=0.004). Only three children (6%) in the ultrasound-guided group needed postoperative rectal acetaminophen compared with 20 children (40%) in the fascial click group (P<0.0001).

Ultrasound-guided ilioinguinal/iliohypogastric nerve blocks can be achieved with significantly smaller volumes of local anaesthetics. The intra- and postoperative requirements for additional analgesia are significantly lower than with the conventional method.