Microsurgical management of lateral lumbar disc herniations: combined lateral and interlaminar approach.

Seventy-three patients presenting either with biradicular symptoms caused by involvement of the upper and lower root or with monoradicular symptoms caused by affection of the upper root were treated between January 1993 and July 1995 in our department. An interlaminar and lateral access was used to decompress both the upper and lower root by combining the conventional interlaminar approach and a lateral partial facetectomy. With this technique, satisfactory to excellent results were obtained in 92% of the patients. The advantages of the combined approach are (i) optimized visualization of the disc and surrounding anatomical structures, (ii) improved exposure of the lateral foramen and thorough removal of disc material, (iii) minimal risk of root injury by improved visualization, (iv) preservation of a functional facet joint and thereby reduction of postoperative instability with persistent back pain. Since occasionally lateral disc herniations are poorly visualized by computed tomography or magnetic resonance imaging, the decision to use the combined approach should be guided by the patient's clinical presentation rather than by radiological findings.