Assessment of range of motion and muscle strength after idiopathic scoliosis surgery using fusion or anterior dynamic fixation

To assess the changes of range of motion and spinal muscle strength after surgical correction of adolescent idiopathic scoliosis with the use of an intelligent biofeedback system. Retrospective study of 48 adolescent idiopathic scoliosis patients: posterior fusion, PFS (Group 1, n = 22), anterior scoliosis correction (dynamic fixation) (Group 2, n = 14), and hybrid fixation (Group 3, n = 12). Range of motion and isometric strength were assessed using the Tergumed Pegasus 3D system. Statistical analysis used Mann–Whitney U and Kruskal–Wallis tests (p < 0.05). Group 1 (PFS) had the worst outcomes: limited rotation (26–31°), 47.5 % reduced extensor strength, and only 52.5 % of normal rotation. Group 2 (ASC) showed improved rotation (39–47°) and doubled extensor strength (143.5 Nm). Group 3 (hybrid fixation) had the best results: near-normal rotation (47–48°), full extensor strength recovery (106 %), and 95 % of retention of available mobility. Group 2 and Group 3 outperformed Group 1 in rotation degrees, while Group 3 showed better flexion, extension, and lateral bending. Back extensor strength in Group 1 was half that of Group 2 and Group 3. Group 3 did better than Group 1 in both range of motion and strength, while there were no significant differences between Group 2 and Group 3. When using anterior (dynamic) scoliosis correction, the amount of spinal movement is greater, compared to posterior fusion. Muscle strength is also significantly higher during extension. Therefore, ASC is an effective method of scoliosis treatment and further research with more cases is needed to have better understanding of its benefits.