Study of the ossification of the iliac apophysis as an indicator of skeletal maturity and its clinical significance in idiopathic scoliosis
Chen, W.S.
Nihon Seikeigeka Gakkai Zasshi 57(6): 593-606
1983
ISSN/ISBN: 0021-5325 PMID: 6619624 Document Number: 198589
Ossification of the iliac apophysis has been used as a convenient indicator for skeletal maturity in the treatment of scoliosis for it can be assessed on the same roentgenogram taken for scoliosis. The stage of the maturity among Japanese teenagers was studied and reported. However, the recent tendency of Japanese youngsters toward early physical development prompted the restudy of the ossification of the iliac apophysis with the same methods used by the previous investigator. Normal pelvic antero-posterior roentgenograms taken for non-orthopedic problems in non-scoliosis patients and the ones of the normal individuals screened out at school scoliosis examinations were subjected to study. They consisted of 430 boys and 431 girls, totaling 861 individuals. The maturity indices obtained from the normal control group were compared with those of 506 (77 male and 429 female) patients with idiopathic scoliosis seen at scoliosis service. The maturity index of the normal group appeared to precede about 1 yr the report made 15 yr ago. The iliac apophysis appears at 13 yr of age in males and 12 yr of age in females on an average. It reaches full excursion at 15 yr of age in males and 14 yr of age in females, after which it takes about 4 yr for complete ossification. In comparison to the scoliosis and the normal groups, both groups failed to show significant differences throughout the ages, except for the fact that the maturity index is slightly higher in the scoliosis group at age 11 (P < 0.10) and that it is slightly higher in the non-scoliosis group at age 18 (P < 0.05). In comparison to 188 patients with mild scoliosis (10-25% Cobb) and 47 patients with severe scoliosis (over 45), there was no significant difference in the bone maturity. In comparison to 34 progressive scoliosis patients and 45 non-progressive patients followed > 2 yr (average; 3 yr and 11 mo.), no significant difference was observed except for a few exceptional cases. Differences in the maturity indices from right to left were noted in about 9% of both the non-scoliosis and the scoliosis groups. This had nothing to do with the laterality of the scoliosis curve. There was a close correlation between the maturity index and the menarche of the patients. In view of the fact that it takes only one year from Risser sign 1-4 whereas it takes several years from Risser sign 4-5, a new staging of the iliac apophysis maturity is proposed for better clinical application: stage 1 before the appearance of the apophysis, stage 2 from the appearance to full excursion, stage 3 at the beginning of the union to the main ilium and stage 4 until the complete union.