Clinical Study of Microendoscopic Decompressive Laminotomy for Treatment of Lumbar Spinal Stenosis

The patients undergoing microendoscopic decompressive laminotomy (MEDL) for lumbar spinal stenosis (LSS) between will be enrolled in this prospective study. The patients included must fulfill the following selection criteria:

• neurogenic claudication or radicular leg pain with associated neurologic signs referring to the LSS syndrome;
• moderate to severe spinal canal stenosis shown on cross-sectional imaging such as MRI or CT scan;
• failure of conservative treatment for at least three months.

The patients who presents with either mechanical low back pain or segmental instability. Mechanical lower back pain is defined as pain that was induced by posture change, or that prevents the patient from sitting or standing for more than 30 minutes. Patients are considered to have segmental instability if they had isthmic spondylolisthesis, degenerative spondylolisthesis with more than 4 mm of translation or intervertebral angle reversal on dynamic radiographs.18 Surgical techniques

All the surgical procedures will be performed by a single surgeon (J. P.). The patients is positioned prone on the Relton-Hall frame after general anesthesia. Decompression is done under the endoscope with the tubular retraction system METRx (Medtronics, Minneapolis, MN). For patients with unilateral neurological symptoms, we will perform unilateral laminotomy and foraminotomy. For patients with bilateral neurological symptoms, we will performe unilateral laminotomy for bilateral decompression (ULBD) to decompress the central canal and bilateral lateral recesses.

When performing multiple-level decompression, the skin incision will be centered at the midpoint between selected intervertebral disc levels. The incision can be mobilized one level above or below after releasing the underlying connective tissues. Then we can set up the tubular retractor system through separate muscular portals for each level. For patients with small stature, we can perform a three-level surgery through a single surgical wound, just as the same size as we perform the single-level surgery.