Lumbar Spondylolisthesis and Stenosis Treated with Interbody Fusion Cages: A Five Year Experience

Treating spodylolisthesis and stenosis requires neural element decompression and consideration of spinal stability. Studies in the literature have documented poor outcomes and slip progression when fusion doesn't accompany laminectomy. Treatment with interbody fusion cages (IFC) for these patients is controversial; some claim cages cannot stabilize a listhetic spine. This review of patients treated over five years addresses this controversy.

Records, radiographs and outcome questionnaires for 50 consecutive cases of spondylolisthesis and stenosis treated with IFC were reviewed. Anterior and posterior surgical approaches were performed. An independent statistician analyzed all data. Average follow–up was 22 months and age 55; 72% were females. Slip etiology was 60% degenerative, 26% isthmic and 14% iatrogenic. Eight patients had grade 11 spondylolisthesis. Although three patients had poor results, 94% were satisfied, performing work/daily activities, rating themselves excellent, good, or fair.

Radiographs were reviewed by independent radiologists with documentation of two failed fusions both treated with reoperation. Complications included one nerve root injury, one cage displacement, and six incidental durotomies. Some surgeons feel IFC without pedicle screw fixation will not stabilize a listhetic spine despite animal and cadaver studies showing increased segmental stiffness.

In this study, patients with spondylolisthesis and spinal stenosis treated with posterior decompression and IFC and those with postiaminectomy subluxation and canal deformity treated with reduction and cages anteriorly achieved satisfying outcomes, a high fusion rate and avoidance of slip progression. The results of the current study suggest that interbody fusion cages are an option when treating adult spondylolisthesis and spinal stenosis.