Foraminal stenosis and single-level degenerative disc disease: a randomized controlled trial comparing decompression with decompression and instrumented fusion.

STUDY DESIGN: A randomized controlled trial with 5-year outcome data.

OBJECTIVE: To compare clinical outcomes following spinal decompression (Group 1) with those following decompression and instrumented posterolateral fusion (Group 2) and decompression and instrumented posterolateral fusion plus transforaminal interbody fusion (TLIF) (Group 3).

SUMMARY OF BACKGROUND DATA: Decompression is frequently advocated for the relief of nerve root stenosis in the presence of degenerate disc disease. It is uncertain if spinal fusion is also necessary.

MATERIALS AND METHODS: Following completion of a standardized physiotherapy program, 44 patients with single-level disc disease were randomly assigned to 1 of 3 surgical groups. In those patients undergoing instrumentation, segmental pedicle screw fixation was used to stabilize the spine. Titanium interbody cages filled with autologous bone were inserted into patients in Group 3. Spinal disability, quality of life, and pain were assessed before surgery, and then at 1, 2, and 5 years by an independent researcher.

RESULTS: At 2 years, 82% of the patients were pain free or moderately improved. Disability (Low Back Outcome Score and Roland Morris index) were both better in Group 1, but only Low Back Outcome Score was better in Group 2 (P < 0.05). By 5 years, although patients in all 3 groups showed some improvements in all the ratings used (Low Back Outcome Score, SF-36 Physical Functioning, and Roland Morris score), only Group 1 patients showed significant changes in all 3 outcomes (P < 0.05). There was no difference in any score between groups (P > 0.05). Two had secondary surgery for adjacent level stenosis (Group 2 and 3). One patient (Group 1) underwent subsequent lateral mass fusion for chronic pain. No patient required revision surgery for instrumentation failure, cage displacement, or pseudarthrosis. Evidence of at least unilateral lateral mass bone graft incorporation was evident in 95% of Groups 2 and 3.

CONCLUSIONS: The results are encouraging in that almost all patients had improved by 5 years. However, it is a concern that no significant additional benefit has been noted from the more complex surgery. This suggests that patients are optimally treated by decompression alone, with the proviso that further operations may be required.