A Morphometric Study Analyzing the Anterior Epidural Space Volume Throughout Childhood

BACKGROUND: Following disc herniations, fragments migrate into the anterior epidural space within the lumbar spine. Although the volume of this area has been previously described in the adult population, the volume is relatively unknown within children. OBJECTIVES: Investigate the relative volume in the lumbar anterior epidural space within the growing spine by using imaging studies. STUDY DESIGN: Retrospective chart review. SETTING: University Medical Center in Lubbock Texas. A teaching hospital affiliated with Texas Tech University Health Sciences Center. METHODS: We conducted a retrospective review of the charts of pediatric patients seen at our institution from 2018 through 2020. Charts chosen for our investigation contained computed tomography imaging of the lumber spine, showing no deformities. Thirty patients were stratified equally among 3 age groups, 2-5 years old, 10-12 years old, and 16-18 years old. The anterior epidural space was measured in each patient 3 times using the previously reported method used by Teske et al (1). Results were compared with a combination of analysis of variance (ANOVA) and single tail paired t test. RESULTS: There was a statistically significant difference in the anterior epidural space size among age groups at all levels of the lumbar spine. When comparing only 2 groups together, the younger age group had anterior epidural space sizes significantly smaller than the other age group for all levels of the lumbar spine. The 10-12 age group had a significantly smaller space in the anterior epidural space than the 16–18-year olds only at the level of L2, L4, and L5 (P = 0.048,0.039, and 0.031, respectively). Within the 16–18-year age group, the anterior epidural space was significantly different between L4 and L3 and L2 and L3 (P < 0.001 and P = 0.019, respectively). LIMITATIONS: Our study is limited by its retrospective nature and the sample size of the patient groups. Furthermore, the use of computed tomography imaging and not making physical measurements limits our accuracy. CONCLUSION: The volume of the anterior epidural space is smaller in the pediatric population than the adult population. The inability of herniated discs to fit within the epidural space in children and adolescents could potentially be the cause of the increased failure of conservative treatment for pediatric lumbar disc herniations. KEY WORDS: Anterior epidural space, lumbar herniated disc, low back pain, fossa corporis vertebralis dorsalis, free di