Abstract
Introduction
Traditionally correction of idiopathic paediatric scoliosis is done by hybrid fixation. This involves a judicious combination of mono-axial and poly-axial screw constructs. This has inherent perceived advantages with better deformity correction and maintaining alignment without loss of correction over time.
Study design
Single centre retrospective review of prospective collected data on the radiological analysis of idiopathic paediatric scoliosis corrections. The study compared hybrid screw constructs (poly-axial & mono-axial) to all poly-axial screw constructs over 28 months.
Objective
Compare loss of correction between hybrid screw construct group (HSG) and all poly-axial screw construct group (PSG).
Method
Retrospective review of preoperative, post-operative and latest follow-up radiographs on the cohort of 42 consecutive patients over a period of 28 months from a single surgeon series.
Results
There were 19 patients (16 females, 3 male) in HSG and 23 (18 females, 5 male) in PSG. Average age at surgery was 14 years for HSG and 15.8 years for PSG.
The average baseline Cobbs angle for HSG was 64.57°and 60.79° for PSG. In the HSG, on average 11.6 levels were fused and, in the PSG, it was 11.3 level. Mean screw density for HSG was 1.54 and PSG was 1.6.
Mean correction from pre-op to immediate post-op was 46.06° (70.10%) in the HS group and 41.24 degrees (67.78%) in the PS group. At the last follow-up, mean correction was 45.12° (68.0%) for the HSG and 42.43° (70.39%) for PSG.
Loss of correction from post-operative radiographs to latest follow up averaged 10.05% in HSG and 3.86% for PSG.
Discussion
All poly-axial screw constructs has the advantage of minimal tray inventory, simple logistics, decreased surgical time and overall better efficiency. Rod application and derotation over poly-axial screw constructs is well controlled and we found no difference in the performance of these screws during and after the procedure.
Conclusion
There was no statistically significant difference in the degree or loss of correction in HSG or PSG. No difference in radiological outcomes. In poly-axial pedicle screw construct, threading the rod and correction manoeuvres are easier and thereby reducing surgical times. There was no compromise on the derotation manoeuvre and correction of the apical rotation deformity. Our findings show that all poly-axial screw constructs in the management of idiopathic scoliosis corrections is emerging as a tangible alternative for the future.
