Introduction: The lateral femoral cutaneous nerve (LFCN) has a variable course, from medial to the anterior superior iliac spine (ASIS) upto 5 cm lateral to the ASIS. Moreover the nerve runs in its own fascial sheath which forms a tunnel that circumferencially surround the nerve. This renders its surgical localization difficult and sometimes very time-consuming. We have adopted preoperative ultrasound (US) wire localization of the nerve in order to facilitate surgical localization.

Methods: The day of surgery, the patients are taken to the US suite where a high resolution US is performed to localize the ASIS and the LFCN. Then, the patient is prepped and draped, and an interventional radiologist proceeds with the wire localization. The patient is injevted with a local anesthetic. A wire is advanced with a needle lateral then deep to the nerve below the inguinal ligament. As the needle is withdrawn, the wire hooks up around the nerve. A sterile dressing is applied, then the patient is taken to the operating room. The patient then undegoes general anesthesia, and the skin including the wire is reprepped and draped. A skin incision is then made medial to the wire, and the wire is followed until the deep fascia. At that point the wire is seen hooking around the nerve. The deep fascia is opened and the nerve is circumferencially exposed. The wire is removed, and the nerve is decompressed proximally until the inguinal ligament is opened. Then the wound is irrigated and closed with resorbable sutures.

Results: Our skin to nerve time ranged from 11 -19 minutes, with an average of about 15 minutes. In one case the localization was wrong, where a cutaneous branch of the femoral nerve was localized. This was easily recognized intraoperatively, we then undermined the incision laterally to find the LFCN and decompress it.

Conclusions: High resolution ultrasound is a safe and effective method of preoperative localization of the LFCN Operating time could be reduced by using preoperative loclization.

Patient Care: If surgeons apply this novel application of US, surgery on the LFCN would be easier, safer, and less time-consuming.

Learning Objectives: 1. Becoming more familiar with the anatomy of the lateal femoral cutaneous nerve 2. High resolution ultrasound is a safe and effective method of preoperative localization of the LFCN 3. Operating time could be reduced by using preoperative loclization

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