Clinical results of posterolateral fusion for degenerative lumbar spinal diseases: a follow-up study of more than 10 years.

Abstract

The objective of this retrospective study was to evaluate the long-term clinical outcomes and the effects on unfused motion segments of posterolateral fusion. This study involved 35 cases (37 intervertebral levels) of posterolateral fusion performed to treat degenerative lumbar spinal diseases. There were 20 male and 15 female patients ranging in age from 30 to 67 years, with a mean age of 49 years. The postoperative period ranged from 10 years to 17 years and 8 months, with a mean period of 13 years. The clinical outcomes were evaluated using the Japanese Orthopaedic Association (JOA) score for assessment of treatment for low back pain. The effects on unfused motion segments were investigated with radiographic and magnetic resonance (MR) imaging. Postoperative satisfactory improvement (mean recovery rate, 66.9%) reached a plateau at 1 year and was maintained at final follow-up. Radiographically, the union rate was 86.5%. There were few cases of induced instability of unfused motion segments. On MR imaging, increased signal intensity in both T(1)- and T(2)-weighted images was seen in the paravertebral muscles in 15 of 20 cases (75.0%). Posterolateral fusion is a useful technique for the treatment of degenerative lumbar spinal diseases. Clinical outcomes were stable throughout follow-up. Instability of unfused motion segments rarely occurred.