[L5 sciatica caused by the compression of the lumbo-sacral trunk of osseous origin at the sacro-iliac level. Treatment by an antero-lateral subperitoneal approach].

A 42 years old patient presented with a 4 years history of a left L5 sciatica unresponsive to a previous L4-L5 surgical decompression. CT scan showed a solid tumor developed on the anterior aspect of the sacro-iliac joint, in contact with the lumbo-sacral trunk. An antero-lateral extraperitoneal approach was performed, with progressive subperitoneal dissection along the inner aspect of the iliac wing to the sacro-iliac joint and sacral ala. The exostosis was removed with "en block" excision, Postoperatively pain completely disappeared. Considerations are made on the mechanism of the compression as well as on the surgical approach performed.