Unilateral Approach for Bilateral Microsurgical Decompression of Lumbar Spinal Stenosis: Synopsis of 15 Years of Experience with this Surgical Method

Abstract

Introduction The surgical aim in the treatment of symptomatic lumbar spinal stenosis is the relief of the patient's complaints by an adequate neural decompression. In a preliminary cadaver study the unilateral laminotomy for bilateral access to the lumbar spinal canal was investigated, and the experiences were evaluated in a clinical study. Material and Methods Microsurgical decompression was performed by partial resection of the ipsilateral facet, the medial portion of the laminar arch, the contralateral facet and by complete removal of the ligamentum flavum bilaterally. Anatomical, radiological and morphometrical studies on 4 adult cadaver spine specimens have proved the feasibility of this unilateral approach. Complete bilateral flavectomy and partial bilateral facetectomy were the essential surgical steps for an adequate operative decompression. The clinical practicability in the treatment of lumbar spinal stenosis was initially confirmed in 254 patients. Results The postoperative morphometric evaluation in the cadaver study clearly demonstrates that bilateral ligamentectomy and recess decompression were adequately and successfully achieved via unilateral approach. The clinical evaluation of this technique was performed in 254 patients with symptomatic mono- or multisegmental lumbar stenosis. Postoperatively, 229 of the 254 patients with neurogenic claudication (90.2%) demonstrated a marked improvement of the walking distance. The follow-up of 249 patients (mean follow-up time was 37 months) demonstrated an excellent result without pain in 77 patients (30.9%); a good outcome with mild residual pain, but a normal working capacity in 130 patients (52.2%); and a fair outcome with unchanged postoperative low-back pain but markedly improved working capacity and walking distance in 41 patients (16.4%). There was only one patient with surgically induced, permanent neurological deterioration (0.5%). In nine patients, an inadvertent dural tear occurred, and due to unchanged symptoms three patients with a multisegmental stenosis had to be re-operated on at an additional level. During the past 15 years the author has experience with this method in over 1600 microsurgical decompression procedures. Conclusion Unilateral laminotomy and bilateral spinal canal decompression represents a safe, effective and minimally invasive surgical method and meanwhile is a routine microsurgical strategy for the treatment of patients with lumbar spinal stenosis.