Infraorbital nerve block in neonates for cleft lip repair: anatomical study and clinical application.

Infraorbital nerve block in neonates is not well described although it has been suggested that bilateral infraorbital nerve block is the local analgesic technique of choice for early repair of cleft lip. The purpose of this study was to determine the location of the infraorbital nerve in neonatal cadavers and to identify clinically useful landmarks. Thirty infraorbital nerves were identified in 15 neonatal cadavers with a mean weight of 2.85 (SD 0.32) kg (range 2.45-3.5 kg) via an upper buccal sulcus incision. The mean distance from the infraorbital nerve to the base of the alae nasi was 7.7 (SD 1.3) mm on the left and 7.5 (0.8) mm on the right. A line drawn from the angle of the mouth to the midpoint of the palpebral fissure measured 30.6 (1.9) mm (left) and 30.7 (1.8) mm (right). The nerve was situated approximately halfway along this line at a point 15.5 (1.5) mm (left) and 15.2 (1.4) mm (right) from the angle of the mouth. These measurements were used to perform bilateral infraorbital nerve blocks in four neonates undergoing cleft lip surgery under general anaesthesia, thereby providing analgesia with minimal risk of respiratory depression.