A microsurgical bilateral ligamentectomy via a unilateral approach was performed in patients with intermittent claudication due to central lumbar stenosis. Twenty-eight patients (23 males and 5 females) between the ages of 45 and 79 years have been treated. The cauda equina was compressed by a thickened ligamentum flavum at L4-5 in most patients and at L3-4 and/or L5-S1 in 14 patients. Seven patients had spondylolisthesis at L4-5. A unilateral approach from the left side was selected in most patients. After partial drilling of the spinous process and lamina with a dome laminectomy, the thickened ligamentum flavum was removed bilaterally. An ultrasonic bone scalpel (bone-removal bar) was used to perform the dome laminectomy and partial facetectomy; this instrument is safe to use because it produces vibration without rotational movements. The dural sac was decompressed, and cauda equina decompression was confirmed though the dura. Most patients were able to walk one day after their operation. Intermittent claudication improved postoperatively in all patients. No recurrence or spondylolisthetic deterioration has been observed in a 7 years follow-up. This approach is a safe and effective treatment for central lumbar stenosis, although long-term follow-up studies are required.
