Developmental sacral morphology: MR study from infancy to skeletal maturity

The primary aim of this study was to document the growth and spatial relationship of the sacrum in relationship to the lumbar spine and the ilium during childhood and adolescence.

MRIs of 420 asymptomatic subjects (50% female) with age range 0-19 years at the time of their MRI (mean ± SD 8.5 ± 5.5 years) were used to characterize the reference distributions of MRI anatomic measurements as a function of age and gender. Eight dimensional measurements and eight angles were measured using PACS tools. Reliability of the measurements was studied on a subset of N = 49 images (N = 24 males; mean ± SD age 6.8 ± 5.2 years).

The dimensional measurements increase with age, often with a rapid "growth spurt" in the first few years of life, with a decreased but steady rate of growth continuing until the late teenage. An exception is the S1 canal width, which reaches near-adult size by age 5. Angle measures are less dependent on age or gender, and the associations with age are not necessarily uniformly increasing or decreasing.

These data on the sacral morphology are a valuable information source for surgeons treating young patients for deformity of the spine and pelvis. Knowledge of normative data of children through growth may allow for adaptation of adult surgical techniques to this pediatric age-group of patients. These slides can be retrieved under Electronic Supplementary Material.