A Longitudinal Retrospective Study to Determine the Incidence and Risk of Progression of Spondylolisthesis in Children With Spina Bifida

Introduction: There is very little research evidence regarding the relationship between spina bifida and spondylolisthesis in the lumbar spine, but conventional thinking suggests that patients with spina bifida would have a higher incidence of spondylolisthesis due to the absence of the important posterior elements. This longitudinal retrospective study examined the incidence and risk of progression of spondylolisthesis in a population of children with spina bifida.

Materials and Methods: Sixty-three patient records and x-rays were reviewed from patients who had a history of a myelomeningocele with varying levels of spina bifida. The mean patient age at the time of initial orthopaedic physician visit was 46.2 months, and 52% (33 of 63) were male.

Results: Radiographs were evaluated by two separate reviewers, and their measurements were compared to test inter and intra-rater reliability. Both were very high (r = 0.99). Of the patient records examined, 28.6% (18 of 63) of patients with spina bifida were found to have a spondylolisthesis. This compares to an incidence of 5.8%15 in the general public. Chi squared analysis found this difference to be statistically significant (p = 0.0001). Results also showed that among the records reviewed, 68% (43 of 63) of patients were ambulatory. These ambulatory patients had twice as high a rate of spondylolisthesis as non-ambulatory patients (chi squared, p = 0.0035). The level at which spina bifida occurred and if present, the grade of spondylolisthesis, was recorded for each patient. Fourteen (28%) patients possessed a grade I, and four (6.3%) were determined to possess a grade II spondylolisthesis. Spondylolisthesis was noted at the L5-S1 level in sixteen patients. No progression was noted longitudinally (mean length of follow-up 4.7 years; minimun of two years). The correlation between the level of spina bifida and the percentage slip of spondylolisthesis was poor [correlation coefficient (r2 ) = 0.03]. Seven (11%) patients noted to have spondylolisthesis also possessed scoliosis.

Conclusion: Our conclusion is that spondylolisthesis does occur at a much higher frequency in patients with spina bifida. This frequency is doubled in patients who are ambulatory, but does not appear to be correlated with the spinal level of the defect.