Anomalies of the lumbosacral nerve roots.

The congenital anomalies of the lumbosacral nerve roots have frequently been found in the past as operative findings during surgery for protruded disc and are today diagnosed preoperatively with increasing frequency. They include the more cranial or more caudal origin of a nerve root, the conjoined structure of two roots and the anastomoses between two or more roots. This study reviews the large amount of literature on these anomalies and discusses their incidence, classification and embryological origin, the anatomical structure of the anomalous roots, their clinical presentation and radiological diagnosis. Anomalous nerve roots are often asymptomatic; radicular symptoms may appear in the presence of a protruded disc or lumbar stenosis, as a result of the compression or traction of the anomalous root. Myelography with water-soluble contrast media allows a good visualization of the root sheaths and thus a good diagnostic definition of these anomalies. In symptomatic cases, the surgical treatment consists of the removal of the disc hernia, associated with hemilaminectomy and foraminotomy, to obtain a good mobilization of the anomalous root; it usually results in the remission of the radicular symptoms.