There is limited long term evidence to support instrumented fusion as an adjunct to decompression for foraminal stenosis in the presence of single level degenerative disc disease.

We report the long term outcome of a prospective randomised controlled trial. Forty-four patients with single-level disc disease were randomly assigned to three groups (spinal decompression (Group 1), decompression and instrumented posterolateral fusion (Group 2), or decompression and instrumented posterolateral fusion plus transforaminal interbody fusion (Group 3). Spinal disability (Dallas, Roland Morris, and Lower Back Outcome Score [LBOS]), and quality of life (EuroQol (EQ) and short form (SF-) 36 questionnaires) were assessed before and at after surgery by independent researchers.

At mean of 15 years follow up 33 (75%) patients were available for assessment. All groups observed a significant improvement in the EQ-5D at final follow up. Group 1 demonstrated significantly better functional outcome at final follow up according to the Dallas, Roland Morris, LBOS, and EQ-5D (3L and VAS) scores when compared to the other two groups (p<0.01). The SF-36 score demonstrated that group 1 had significantly better generic health scores compared to groups 2 and 3. Regression analysis was used to adjust for the differences in general health between the groups and demonstrated no significant difference between the groups in the spine specific scores: Dallas (p>0.15), Roland Morris (p>0.37), or the LBOS (p>0.32).

Fusion in combination with decompression for the treatment of foraminal stenosis and single level degenerative disc disease offers no long term functional benefit over decompression in isolation.