Long-term results in patients treated with posterior instrumentation and fusion for degenerative scoliosis of the lumbar spine

The authors report a homogeneously investigated and surgically treated series of 40 patients with degenerative scoliosis of the lumbar spine. The series included 22 females and 18 males with a mean age of 62.8 years. The clinical presentation, the diagnostic work-up, the indication for surgery, the surgical techniques and results are reported. Final evaluation was possible in 30 patients at a mean period of observation of 59.5 months. Following a very precise diagnostic and therapeutic protocol excellent, good and satisfactory surgical results were obtained in 13 (43.3%), 16 (53.3%) and 1 (3.3%) patients, respectively. While scoliosis was converted from a mean preoperative Cobb angle of 18.7 degrees to 7.6 degrees mean pre-operative lumbar lordosis was slightly augmented from 37 degrees to 41.5 degrees. The results suggest that maintainance or correction of lumbar lordosis is more important than the conversion of the scoliotic deformity which is probably treated sufficiently by partial correction and stabilization. Observation over time indicates that the degenerative cascade evolves despite internal fixation and fusion in the majority of the patients until a stable state is reached. This stable state is probably rather the result of ankylosis of the facet joints than the effect of posterolateral fusion.