Irrigation endoscopic decompressive laminotomy. A new endoscopic approach for spinal stenosis decompression.

BACKGROUND CONTEXT: The classic surgical treatment of spinal stenosis involves bilateral dissection of paraspinal muscles to expose all the involved levels, wide laminectomy, and medial facetectomy and foraminotomy. The surgical morbidity of the procedure is further magnified by being more common in elderly with associated medical comorbidities and being usually global involving multiple levels. To address this problem, several less invasive techniques have been introduced over the past decade including the microendoscopic decompression.

PURPOSE: The aim was to describe and evaluate a new endoscopic technique for lumbar spinal canal decompression named irrigation endoscopic decompressive laminotomy.

STUDY DESIGN: This was a technical report.

PATIENT SAMPLE: One hundred four consecutive patients suffering from neurogenic claudication and resistant to 3 months of conservative management were included in the study. Grade I degenerative spondylolisthesis and degenerative scoliosis were not considered a contraindication. Patients with segmental instability and predominant low back pain were excluded.

OUTCOME MEASURES: Primary outcome measures included the final functional outcome using modified Macnab criteria and the Oswestry Disability Index (ODI). In addition, the operative time and complication rate have been evaluated. Secondary outcome measures included the evaluation of the early postoperative course using visual analog scale for postoperative incisional pain, time for ambulation, and length of hospital stay.

METHODS: Two 0.5-cm portals were used, one for the endoscope and the other for instruments. For every additional level, one portal is added. The endoscope and instruments are directly placed over the surface of lamina without any dissection, and saline under pump pressure is used to open a potential working space. Unilateral laminotomy/laminectomy is performed according to the severity of stenosis, followed by bilateral decompression beneath the midline structures.

RESULTS: Mean follow-up period was 28 months. The final outcome was excellent in 63%, good in 24%, fair in 9%, and poor in 4%. The preoperative ODI dropped from a mean of 64.2±10.0 to 23.1±20.8 postoperatively. Complications were limited to six cases of dural tear, which required no open conversion.

CONCLUSIONS: Irrigation endoscopic decompressive laminotomy allows the surgeon to safely perform effective central and foraminal decompression resulting in satisfactory midterm clinical results. Substituting long surgical incisions with 0.5-cm stabs and direct placement of instruments without dissection or dilatation could result in an improved postoperative course, shortened time for hospitalization, and reduced infection rate. However, still multicenter studies and randomized trials are needed before making final conclusions.