Microsurgical Decompression of Lumbar Stenosis: Technical Innovations and Early Experience of 20 Cases

ABSTRACT

Between March 1995 and March 1996, we used a newly-designed neurosurgical procedure, based on 'keyhole surgery', to operate on 20 patients diagnosed as suffering from lumbar spinal stenosis without instability. The unique surgical steps involved in this procedure are: 1) three-quarter prone position of the patient; 2) small paramedian skin incision; 3) half-way incision of the spinous process; 4) small turnover funnel shaped unilateral laminectomy and wide forminotomy using high speed drills; 5) extensive ligament flavectomy; 6) microsurgical decompression without using nerve root retractor; 7) cosmetic wound closure. In some cases, if bilateral radicular symptom was present, the contralateral nerve root was explored through the unilateral laminectomy opening; this was achieved by changing the inclination of the base of the spinous process and extensively removing of the ligamentum flavum. Compared with conventional procedures, these technical innovations offer both procedural adventages and a better clinical outcome. Because of the small patient populations and short follow-up period, this technique requires further investigation, but we hope it will provide another option for future lumbar stenosis surgery. Further technical refinements and long-term follow-up results will be reported elsewhere.