Pediatric Orthopaedics Journal Scan

Sitting Sagittal Balance is Different From Standing Balance in Children With Scoliosis.

J Pediatr Orthop. 2013 Aug 20;

Authors: Vaughn JJ, Schwend RM

Abstract
BACKGROUND:: Several variables can have effect on sagittal balance. The changes that occur between standing and sitting have been inadequately studied, especially in the, pediatric population.
METHODS:: Preoperative sagittal radiographs were obtained in both standing and sitting positions for 26 patients with idiopathic scoliosis before spinal fusion and instrumentation. Standard measurements of thoracic kyphosis, lumbar lordosis, sacral slope (SS), pelvic incidence, pelvic tilt, and lumbar intervertebral angles were, recorded. Differences were compared between positions using 2-sided paired t tests.
RESULTS:: When moving from standing to a seated position, the spine loses 5-degree thoracic kyphosis (P=0.007), 29-degree lumbar lordosis (P<0.0001), and the sacrum rotates 20 degrees (P<0.0001) to a more vertical position. The greatest change in sitting sagittal balance occurs due to increased pelvic tilt with decreased SS. The next greatest change is increased forward flexion of the lowest 2 lumbar vertebrae, 6.5 degrees between L4-L5 (P<0.0001) and 5.9 degrees between L5-S1 (P<0.0001). Flexion occurs throughout the lumbar spine but its magnitude decreases in the more proximal lumbar segments, 1.6 degrees between L1-L2 (P=0.028). The sagittal vertical axis also moves more anterior by 44 mm (P<0.0001).