Extreme Lateral Lumbar Disc Herniation : Pitfalls in Diagnosis and Operative Treatment

Abstract

The authors report on the surgical treatment of 3 cases of an extreme lateral lumbar disc herniation (ELLDH) and discuss the pitfalls in diagnosis and treatment. As an ELLDH exhibits a nerve root sign that is a level higher than the usual disc herniation, the condition may be misdiagnosed. In this regard, myelography is not useful for diagnosing an ELLDH, since the compression occurs at the distal level of the nerve root. Therefore, CT myelography is the best diagnostic tool, because it can depict an ELLDH at the level of foramen and thus evaluate the relationship between the nerve root and the herniated disc and the bone components. As for the surgical approach to be used, the authors recommend a medial approach under operative microscope, and an extended foraminotomy and a partial resection of the facet, with or without a hemilaminectomy, may lead to successful decompression of the involved nerve root. In the 3 cases that the authors describe, preservation of the facet proved possible. An ELLDH is more frequently seen in eldery patients than the usual herniated disc, so that when encountering what looks to be lumbar nerve root compression, one should be aware of this clinical entitiy.