A Method of Lumbar Expansive Laminoplasty : Unilateral Approach, Bilateral Decompression using Microsurgical Technique

Abstract

Introduction : We accidentally found in a case of lumbar spinal canal stenosis (LSCS) with a highly rotated spine that we could reach the other side of the laterel recess through the one-sided approach without sacrificing the spinal process and the posterior ligaments. Subjects : Sixty patients with LSCS underwent the above described operation from August 1995 to December 1996. All the patients had degenerative LSCS, including 6 cases (6%) of developmental type, 15 cases (25%) of listhetic type. Age; 32 to 79, average age 64.5 years. Thirty three female patients and 27 male patients. Methods : Skin incision; 4cm for one level, 6cm for two levels. Unilateral fascial incision and muscle dissection are followed by fenestration procedure using Casper's retractor. On the opposite side, beginning with drilling the basal portion of the spinal process, the inner surface of the other side lamina is drilled out using air drill or rongeur. After removing the yellow ligament, we can see the lateral recess, the inner aspect of the joint and even the nerve root on that side. Most of the patients can leave the hospital on the 14th day after operation, and discharge might be possible within one week after the operation. Operative results : excellent-8 (13%), good-49 (82%), unchanged-3 (5%), worse-0. Re-expansion of the dural canal was ascertained by postoperative MRIs in all cases, and by myelography and CT-myelography in the selected cases. Conclusion : This is one of the less invasive operation for expanding the spinal canal. Superior results of this operation suggest to us that preservation of the posterior supporting structures of the spine (muscle, ligament, joint, lamina) is essential to success of this operation.