Lumbar Spinal Stenosis: Ipsilateral Facet-sparing Unilateral Laminotomy for Bilateral Decompression: Technical Note and Preliminary Results

Abstract

Microsurgical unilateral laminotomy for bilateral decompression (ULBD) decompresses effectively lumbar stenosis. Whenever low grade degenerative spondylolisthesis, sagittal oriented facet joints, scoliotic deformity, tall disc, and obesity jeopardize postoperative segmental stability, a maximum facet-preserving decompression is desirable. The medialized ULBD (mULBD) aims to preserve the facet joint on the approach side. Sixty-four patients presenting with neurogenic claudication underwent single or multilevel decompression with ULBD or mULBD according to the judgement of the surgeon. The volume of the target facet joints and the dural cross sectional area (CT-DCSA) were measured pre- and postoperatively by an ultra-low-dose CT with a specific software. Forty-three pairs of facet joints were addressed with ULBD and 43 pairs with mULBD. Postoperatively, the mean percentage of the preoperative facet joint volume preserved on the approach side was 70% ± 4% (ULBD) and 88% ± 6% (mULBD); (p<0.001). The mean facet joint volume preserved contraleral to the approach side was 87% ± 6% (ULBD) and 91% ± 6% (mULBD); (p=0.4). The mean postoperative CT-DCSA was 152 ± 30 mm² (ULBD) and 153 ± 26 mm² (mULBD); (p=0.43). The mUBLD decompresses lumbar spinal stenosis effectively as ULBD and preserves better the facet joint on the approach side.

Keywords

• zygapophyseal joint
• spinal stenosis
• spinal canal
• decompression
• spondylolisthesis