Radiographic correlations in adult symptomatic spondylolisthesis: a long-term follow-up study

A follow-up study was conducted on correlations of radiographic measurements of isthmic spondylolisthesis to indexes of low-back pain as well as functional and working capacity in 148 middle-aged patients treated for low-back pain an average of 17 years earlier. Posterior or posterolateral fusion in situ had been performed in 50% and decompression (Gill's procedure) in 23% of patients, whereas 27% of the patients had been treated conservatively. The mean degree of the slip was 34.4 +/- 19.7% (SD) at follow-up, and the mean progression of the slip during the observation time was 6.1% units. The level of progression of the slip, instability of the olisthetic segment, or radiological nonunion of spinal fusion did not correlate with either the pain index or the activities of daily living (ADL) index. No marked radiological differences were seen between those actively employed and those pensioned. The degree of slip correlated positively with the pain index (r = 0.31; p = 0.007) and the ADL index (r = 0.24; p = 0.026) in the joint group of nonsurgical and decompression-treated patients, whereas negative correlations (pain index, r = -0.22, p = 0.065; ADL index, r = -0.22; p = 0.066) occurred in the fusion group. We conclude that degree of slip and spinal fusion operation are slightly associated with the prognosis of isthmic spondylolisthesis, whereas the other radiological variables of our study showed no association.