The effect of age on the change in deformity after anterior débridement surgery for tuberculosis of the spine.

Abstract

This article evaluates how an immature spine responds to anterior débridement surgery (without bone grafting) for spinal tuberculosis during growth and development. Sixty-three patients were studied, 29 of whom were children aged 10 years or less at the time of surgery, whereas the remaining 34 subjects were adults. These patients were the subject of the Medical Research Council Working Party's prospective study, started in Hong Kong in the mid-1960s. To evaluate how an immature spine responds to débridement surgery for tuberculosis, during growth and development, to determine whether there are differences in the longitudinal pattern of deformity between children and adults, and to determine the influence of disproportionate spinal growth on the progression of deformity in children. All patients were followed prospectively for a mean period of 19.6 years after débridement surgery. The mean age at surgery for children (n = 29) was 4.3 years and for adults (n = 34) 35.3 years. The kyphos and deformity angles were measured from lateral spinal radiographs obtained at preoperative evaluation and postoperatively at 6 months, 1 year, 5 years, and at final follow-up evaluation using an electronic digitizer. The results showed that the longitudinal pattern of changes in the mean kyphos and deformity angles in young children presented a picture slightly different from that in adults. The mean angles were increased at the 6-month and at 1-year evaluations after débridement surgery in both groups. Afterward, in children there was some spontaneous correction in these mean angles, whereas in adults these angles showed variation according to the site of lesion during the follow-up years. Statistical analysis according to the site of spinal lesion showed that in thoracic tuberculosis, there was an increase in kyphos and deformity angles at the 6-months postoperative evaluation (more in children than in adults). There were no significant changes in these angles from the 1-year to the final follow-up evaluations. In thoracolumbar tuberculosis, there were significant increases in kyphos and deformity angles at the 6-month postoperative evaluation, and thereafter adults did not show any significant change until final follow-up examination, whereas children showed a tendency toward spontaneous correction, although this finding was not statistically significant. In lumbar tuberculosis, there was an equal tendency toward spontaneous correction in children and adults from 1 postoperative year onward. The authors could find no evidence of disproportionate posterior spinal growth, which has been suspected in the past to be a factor involved in contributing to progression of kyphotic deformity after anterior débridement surgery for spinal tuberculosis.