Computed tomographic-based volumetric reconstruction of the pulmonary system in scoliosis: trends in lung volume and lung volume asymmetry with spinal curve severity.

BACKGROUND: Scoliosis has been associated with reduced pulmonary capacity; however, the source of the reduction in capacity (left, right, or both lungs) is not clear. The objective of this study was to investigate trends in left, right, and total lung volume and left/right lung volume asymmetry with spinal curve severity in scoliosis.
METHODS: Three-dimensional volumetric reconstruction of the pulmonary system was performed on existing preoperative computed tomographic (CT) scans for 28 idiopathic scoliosis patients. Left, right, and total lung volumes, and left/right lung volume ratios were calculated and correlated with the following spinal curve parameters: major Cobb angle, rib hump, number of vertebrae in the major curve, most cephalad vertebra in the major curve, and thoracic kyphosis.
RESULTS: Left/right lung volume ratio increases significantly with increasing rib hump. Left, right, and total lung volumes were significantly correlated with rib hump and number of vertebrae in the major curve (P < 0.05), and near-significantly correlated with most cephalad vertebra in the major curve (P < 0.10). Shorter, higher, more rotated thoracic curves therefore restrict lung volume more than longer, lower, less rotated curves. The mean lung volume ratio for scoliosis patients was lower than for age-matched controls (P < 0.10).
CONCLUSION: CT-based volumetric reconstruction of the pulmonary system in scoliosis patients shows differences in both lung volumes and lung volume ratios compared with normal controls.