Sixteen patients with high-grade spondylolisthesis (Grade III or higher) who underwent posterior decompression and reduction using the Edwards Modular Spine System (Spinal System Ltd., Baltimore, MD) were reviewed clinically and radiographically.
This study was undertaken to determine the efficacy of one specific reduction technique to treat patients with high-grade spondylolisthesis where there has been a loss of sagittal balance, intractable pain, and/or neurologic deficit.
The average age of our patients was 20 years. Preoperative slippage averaged 89%; preoperative slip angle averaged 50°. Indications for surgery were back and leg pain, progression of slippage (in 9 patients), and/or the inability to stand upright with the knees straight.
Pre- and postoperative radiographic films were reviewed. The percent slip and the slip angle were measured pre- and postoperatively. Clinical data were obtained via chart review, telephone interview, and/or office visit.
The average preoperative slip was 89%; postoperatively, the average slip was 29%. Slip angle averaged 50° preoperatively and improved to a postoperative average of 24°. Three patients had neurologic impairment postoperatively; one did not resolve. Four patients had hardware failure; all were revised. Ten patients had an excellent result, 5 patients had a good result, and 1 patient had a fair result. The average follow-up was 3.8 years.
This procedure is technically demanding and is subject to the known risks of surgical treatment for high-grade spondylolisthesis. For select patients, it may be effective for reducing severe deformity and can be expected to afford good to excellent results. Improved sacral fixation may reduce the rate of hardware-related complications.
From the *University of California, San Francisco, California and †Twin Cities Scoliosis Spine Center, University of Minnesota, Minneapolis, Minnesota.
Acknowledgment date: October 31, 1994.
First revision date: March 27, 1995.
Accepted for publication April 25, 1995.
Device status category: 4.
Address reprint requests to: Serena S. Hu, MD; Department of Orthopedic Surgery; University of California; 500 Parnassus Avenue; MU-320W; San Francisco, CA 94143-0728