When evaluating and treating patients with spinal disorders, a significant knowledge of the normal spinopelvic balance is of primary importance. This study documents the spinopelvic balance in normal children and adolescents, and describes a scheme of correlations between morphological, shape and orientation parameters of the spine and pelvis. It is found that the pelvic incidence regulates the sacral slope and pelvic tilt. In addition, shape and orientation parameters of adjacent anatomical regions are interdependent, and their relationships result in a stable posture with minimum energy expenditure.

Evaluate the correlations between spinopelvic parameters in normal children and adolescents.

Seven parameters were evaluated from the lateral standing radiographs of two hundred and eighty-two normal subjects aged three to eighteen years old: thoracic kyphosis (TK), thoracic tilt (TT), lumbar lordosis (LL), lumbar tilt (LT), sacral slope (SS), pelvic tilt (PT) and pelvic incidence (PI). Statistical analysis was performed using Pearson’s coefficients.

The mean PI (morphological parameter) was 49.0±11.3°. The mean values for shape parameters were 41.4±8.5°, 48.0±12.0° and 44.3±11.2° for SS, LL and TK, respectively. The mean values for orientation parameters were 7.5±8.1°, −7.0±5.1° and −2.6±5.0° for PT, LT and TT, respectively. There was no significant difference between males and females. PI was significantly related to SS and PT. Significant correlations were found between orientation and shape parameters of adjacent anatomical regions.

This study describes a scheme of correlations between morphological, shape and orientation parameters of the spine and pelvis. It is found that the pelvic incidence regulates the sacral slope and pelvic tilt. In addition, shape and orientation parameters of adjacent anatomical regions are interdependent, and their relationships result in a stable posture with minimum energy expenditure.

This study presents a postural model in order to better understand the spinopelvic balance in normal children and adolescents. This model could help to evaluate the influence of pelvic morphology on the progression and treatment of pediatric spinal deformities.

This research was funded by an educational/research grant from Medtronic Sofamor Danek, by the Canadian Institute of Health Research, by the Fonds de Recherche en Santé du Québec and by the Fondation de recherche et d’éducation en orthopédie de Montréal (FREOM).