Ring apophysis fracture in pediatric lumbar disc herniation: a common entity.

Background/aims: Lumbar disc herniation (LDH) can be associated with ring apophysis fracture (RAF), which is found in 6% of adult cases. However, the incidence and management of RAF in pediatric LDH is not well documented. The purpose of this study is to determine the prevalence of RAF in pediatric LDH, identify risk factors and explore the influence of RAF on the surgical management and outcome of LDH patients.

Methods: Hospital records and images were retrospectively reviewed for all pediatric patients (<18 years old) who underwent CT scanning for LDH at BC Children's Hospital from 1985 to 2010.

Results: Forty-two patients met the study inclusion criteria. RAF was present in 38% of the pediatric patients with LDH. There was a significant correlation with gender (p = 0.021; 55% of the males had RAF, and 20% of the females) and association with central herniations (p = 0.003). At the last follow-up, 58% of the patients with RAF were symptom free, compared with 68% of the patients with no RAF.

Conclusion: RAF is more frequently associated with LDH in children than in adults. Gender and central disc herniation are associated with RAF. Given the frequency of RAF, to properly identify these fractures and anticipate their treatment, preoperative CT would be necessary.