LAUSR

BACKGROUND Plumb line distances (PDs) are widely used in conservative clinical practice to evaluate the sagittal shape of the spine. OBJECTIVE The objective was to assess the normative values of PDs in a large, healthy population in an age range representative of the adolescent population with spinal deformities, and to correlate it with x-ray measurements. DESIGN This was a cross-sectional study. METHODS Participants were 584 healthy individuals (341 females) with x-rays showing no spine deformities. The whole sample (OVERALL) was divided into 5 groups: 6-9 years old (n = 106); >10 years, Risser 0 with triradiate cartilage open (n = 129) or closed (n = 104); Risser 1-2 (n = 126); and Risser 3-5 (n = 119). PDs were taken by maintaining a tangent to the thoracic kyphosis apex at C7, T12, L3, and S2. Sagittal index (C7 + L3), and sagittal and coronal balances (C7 related to S2) were calculated. RESULTS In OVERALL, PDs at C7, T12, L3, and S2 were 39.9 ± 16.7, 21.4 ± 15.3, 39.9 ± 15, 20.6 ± 17.0 mm, respectively. Sagittal index was 79.8 ± 26.8, sagittal balance was 19.3 ± 17 mm anterior to S2 plumb line; 13.5% had a coronal imbalance of 11.4 ± 5.4 mm to the right and 24.7% of 13.2 ± 6.0 mm to the left. C7 and L3 PDs, sagittal index, and sagittal balance were significantly lower in ages 6-9 compared to older patients in Risser 1-2 group. C7 and S2 PDs and sagittal index were significantly larger in males. Sagittal index correlated with thoracic kyphosis Cobb degrees (r = 0.47). LIMITATIONS The participants were not randomly chosen from the general population; and, they had an x-ray because of spine pathology suspicion. CONCLUSIONS This study shows normative data to be used in clinical practice.