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[Degenerative changes of the lumbosacral transition after Risser and Harrington spondylodesis].

INTRODUCTION
The long-term results of two operation techniques according to Risser and Harrington were of special interest. As part of this study, secondary changes of the lumbar spine, as well as the lumbosacral junction, were evaluated over time.


MATERIAL AND METHODS
Two groups of 20 patients, who underwent one of the above-mentioned operative procedures for idiopathic scoliosis were analyzed (group A: Risser procedure, average age 15 years; group B: Harrington procedure, 17 years of age). The preoperative deformity ranged between 34 degrees and 108 degrees Cobb angle. The patients were evaluated at three different points in time: 1) preoperatively; 2) upon the conclusion of outpatient treatment following the surgery; and 3) between 13 and 15 years postoperatively.


RESULTS
Degenerative changes, especially spondylarthrosis of the lumbosacral region, were seen more frequently in the Harrington group due to the higher rigidity of the implant and the ensuing increased loading of the adjacent spinal segments. The comparison of the two procedures revealed that a better primary correction of the deformity was achieved with the Harrington operation. Moreover, the Risser group showed a higher rate of pseudarthrosis and secondary loss of correction. In the Harrington group we found a higher rate of degenerative arthritis.


CLINICAL RELEVANCE
A better primary correction of the scoliosis leads to a higher strain of the lumbosacral junction. The resultant secondary changes (spondylarthrosis) in this period of observation were rarely of clinical relevance. Nevertheless, whenever possible presacral segments should remain free in the range of a spondylodesis to reduce the loading of the lumbosacral junction.