Does the Prevalence of Spondylolysis and Spina Bifida Occulta Observed in Pediatric Patients Remain Stable in Adults?

Abstract

Introduction The prevalence of spondylolysis reported from radiograph-based studies in children had been questioned in computed tomography (CT)–based studies in adults; however, our group recently confirmed the previously reported data in pediatric populations in a CT-based study. Spina bifida occulta (SBO), which has been associated with spondylolysis, has demonstrated a decreasing prevalence with increasing age during childhood and adolescence. No studies have compared the prevalence of spondylolysis and SBO in pediatric and adult patients using CT as a screening method. The aim of this study was to compare the prevalence of lumbar spondylolysis and SBO in pediatric and adult populations. Patients and Methods We studied 228 pediatric patients (4–15 years' old) and 235 adults (30–45 years' old) who consecutively underwent abdominal and pelvic CT scans at a tertiary care University Hospital for reasons not related to the spine. The entire lumbosacral spine was evaluated to detect the presence of spondylolysis and SBO. We compared the prevalence of spondylolysis and SBO in pediatric patients and adults. Results The mean age of our pediatric patients was 11.2 ± 2.7 years; 107 patients were males (46.9%) and 121 were females (53.1%). The mean age of the adult patients was 37.46 ± 4.5 years; 95 patients were males (40.4%) and 140 were females (59.6%). Among pediatric patients, the prevalence of spondylolysis was 3.5%, 95% CI: 1.1 to 5.9% (eight patients); the prevalence of spondylolysis in adults was 3.8%, 95% CI: 1.7 to 6.8% (nine patients), p = 1. In pediatric patients, males exhibited a 4.7% (95% CI, 0.6–8.7) prevalence of spondylolysis (five patients) compared with a 2.5% (95% CI, 0.3–5.3) prevalence in females (three patients), p = 0.48. In adults, males had a 3.2% (95% CI, 0.0–7.2) prevalence of pars defect (three patients), whereas females exhibited a 4.3% (95% CI, 1.4–8.1) prevalence (six patients), p = 0.74. The prevalence of SBO in pediatric patients was 41.2%, 95% CI: 34.8 to 59.2% (94 patients), while it was 7.7% in adults, 95% CI: 4.3 to 11.5% (18 patients), p < 0.01. The prevalence of SBO decreased with increasing age. Among pediatric patients, SBO was found in 51.4% of males (95% CI, 41.8–61) and in 32.2% of females (95% CI, 23.8–40.7), p < 0.01. In adults, we observed SBO in 8.4% of males (95% CI, 3.3–14.7) and in 7.1% of females (95% CI, 3.1–11.6), p = 0.80. Conclusion The prevalence of lumbar spondylolysis remained constant from pediatric age through adulthood. The prevalence of SBO decreased from 41.2% in children to 7.7% in adults. This finding suggests that SBO may not represent a pathological condition or an anatomic variant; the closure of the vertebral arch may be a continuous process that is completed through adulthood in many patients, which is in opposition to the usual theory that vertebral arch ossification should be completed during early childhood.