INTRODUCTION AND MATERIALS: We examined lumbar transpedicular instrumented posterolateral fusion patients operated on between 1992 and 1997 presenting: degenerative spondylolisthesis with spinal stenosis; adult isthmic spondylolisthesis; failed back syndrome after one to five discectomies; and failed back syndrome after one to three laminectomy operations (groups 1-4, respectively).

Methods: They were examined by an independent orthopedic surgeon, completed the Oswestry Disability Index (ODI) and visual analog scale (VAS) questionnaires and their outcome was evaluated.

Results: The overall patient satisfaction at follow-up (mean 11.7 years) was 82.1%. The reoperation rate was 15.1% (7.5% due to adjacent segment disease).

Conclusions: Group 1 showed the greatest improvements in ODI and VAS values, Group 2 the lowest and Group 3 the highest preoperative values, and Group 4 the second highest improvements. Patient satisfaction scores were 90.3, 69.7, 63.6 and 80.0%, respectively, and unplanned reoperation rates were 6.5, 9.1, 31.8 and 20.0%. Thus, long-term outcomes of lumbar instrumented posterolateral fusion (rarely previously studied) were satisfactory for >80% of patients, but varied among groups.