The subcostal nerve (ouch!): anatomical awareness in Salter's innominate osteotomy.

The identification of the lateral cutaneous branch of the subcostal nerve supplying the anterior gluteal region while using the modified Smith-Petersen approach in performing Salter's innominate osteotomy has not been described previously. Following cadaveric dissection in six specimens and after performing routine Salter's innominate osteotomy using the modified Smith-Petersen approach in five patients, we found consistently that the lateral cutaneous branch of the subcostal nerve crossed the iliac crest between 2 and 5 cm posterior to the anterior superior iliac spine. This important accidental finding has led us to take care in identifying and protecting this nerve from any undue injury that could cause blunting of sensation in the anterior gluteal region.