Lumbar Nerve Root Anomalies are Still a Diagnostic and Therapeutic Challenge. Case Report and Review of Literature

Lumbosacral Nerve Root Anomalies (LNRA) is congenital anomalies that may consist of bifid, conjoined, of a transverse course or of anastomosed nerve roots. It is believed that the development of an anomalous nerve root is secondary to aberrant migration of the involved roots during embryologic development [1]. Firstly, encountered as incidental findings during autopsies they are more frequently described in the last years due to the advances in radiological imaging, especially magnetic resonance imaging (MRI) [2,3]. Nevertheless, most of LNRA cases are still diagnosed during spinal surgery for degenerative spinal lesions only [1,4-6]. The literature demonstrates that LNRA are frequently unor misdiagnosed when relying on standard spinal imaging. In the present report we describe a case of a patient with unilateral lumbar radiculopathy misdiagnosed with a lumbosacral disc herniation on magnetic resonance imaging. During surgery a rare Neidre/MacNab type 2b lumbar nerve root anomaly rather than a disc herniation was verified, which required a wide decompression of the involved neural structures, instead of a microdiscectomy. In an attempt to enhance the awareness of LNRA, the literature is carefully reviewed and the clinical relevance and radiological features of LNRA are discussed from a neurosurgical perspective.