To determine if there is a differing effect between two spinal implant systems on sagittal balance and thoracic kyphosis in adolescent idiopathic scoliosis. Retrospective analysis of pre and post-operative radiographs to assess sagittal balance, C7-L1 kyphosis angles and metal implant density. Group 1 (Top loading system): 11 patients (9 females, 2 males) Single surgeon NB Group 2 (Side loading system): 17 patients (16 females, 1 male) Single surgeon ED Total 28 patients All single right sided thoracic curves Comparison of pre and postoperative sagittal balance and C7-L1 kyphosis angle for each spinal system. Assessment of implant density (i.e. proportion of pedicle screw relative to number of spinal levels involved in correction).Objective
Methods
To determine if the use of high density implants (i.e. high proportion of pedicle screws relative to number of spinal levels involved) causes significant loss of thoracic kyphosis and its effect on sagittal balance in adolescent idiopathic scoliosis. Retrospective analysis of pre and post-operative radiographs to assess sagittal balance and C7-L1 kyphosis angle. 17 patients (16 females, 1 male). All right sided single thoracic curves. All surgery performed by single surgeon (Senior author, ED) Comparison of pre and post operative sagittal balance and C7-L1 kyphosis angle. Assessment of implant density (i.e. proportion of pedicle screw relative to number of spinal levels involved in correction). 9 patients demonstrated improved sagittal balance following surgery. There was no significant difference (p value 0.83) between the pre and post op C7-L1 kyphosis angle. Mean angle pre op 28.9 (95% CI 20.3 to 37.5). Mean angle post op 29.6 (95% CI 22.2 to 37.0). No correlation identified between sagittal balance correction and kyphosis angle. Metal density ranged from 79-100%. Although the sample size in this series is modest, high density implants do not significantly affect the kyphosis angle in the operative management of adolescent idiopathic scoliosis in the thoracic spine.
