Cases report of postoperative adding-on phenomenon in patients with adolescent idiopathic scoliosis and a preliminary classification
YANG Chang-wei
XIA Shi-bo
YANG Ming-yuan
ZHAO Jian
ZHU Xiao-dong
LI Ming
Abstract：Objective To explore the factors and classification of distal adding-on phenomenon in the patients with adolescent idiopathic scoliosis ( AIS ) after correction surgery. Methods Medical records of 14 AIS patients suffering from adding-on phenomenon after surgical therapy in our hospital were retrospectively reviewed. Three different types of adding-on phenomenon were classiifed according to their various parameters such as image, age, skeletal maturity and so on, and clinical and imaging characteristics of each type were summarized. Adding-on phenomenon was divided into 3 subtypes: postoperative shoulder imbalance ( Type I ), postoperative trunk imbalance ( Type II ) and neither shoulder nor trunk imbalance after surgery ( Type III ). Results Signiifcant shoulder imbalance was observed in 6 patients ( 42.9%) immediately after surgery who met the criteria of Type I, with the mean radiographic shoulder height ( RSH ) of 20 mm ( range:15-25 mm ). During the 2-year follow-up, the mean RSH was decreased to 6 mm ( range:0-12 mm ). The mean distal adding-on angle was increased by 14° ( range:5°-23° ). Three patients ( 21.4%) met the criteria of Type II, and the trunk shift was increased from 39 mm to 54 mm after surgery ( average:45 mm ). At the ifnal follow-up, the trunk shift was decreased to 13 mm ( range:8-17 mm ), while the mean adding-on angle was increased by 10° ( range:5°-14° ). Five patients ( 35.7%) who met the criteria of Type III were found well-balanced in both shoulder and trunk after surgery. Risser sign was 0 in all the patients, while their mean adding-on angle was still increased by 10° ( range:6°-15° ). Furthermore, no tendency of progressionor re-operation was noticed in the patients with Type I and Type II during the long-term follow-up. However, 1 patient with Type III received re-operation due to rapid progression of scoliosis. Conclusions Three subtypes of adding-on phenomenon are introduced, as well as their clinical and imaging characteristics, which may make us understand the pathogenetic mechanisms more profoundly.
Keywords：ScoliosisAdolescentMusculoskeletal physiological phenomenaAdding-on phenomenon
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：5( 10-14 )