• Aakash Agarwal, Arvind Jayaswal, Anand K Agarwal, and Vijay K Goel.
• *Engineering Center for Orthopaedic, Research Excellence (E-CORE), Department of Bioengineering and Orthoapedic Surgery, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 †Primus Super Speciality Hospital Chandragupt Marg, Chanakyapuri New Delhi- 110021, India.
• Spine. 2017 Jun 13.

Study DesignA finite element study to establish the relationship between patient's curve flexibility (determined using curve correction under gravity) in juvenile idiopathic scoliosis and the required distraction frequency to avoid growth rod fracture, as a function of time.ObjectiveTo perform a parametric analysis using a juvenile scoliotic spine model (single mid-thoracic curve with the apex at the eighth thoracic vertebra) and establish the relationship between curve flexibility (determined using curve correction under gravity) and the distraction interval that allows a higher factor of safety for the growth rods.Summary Of Background DataPrevious studies have shown that frequent distraction with smaller magnitude of distractions are less likely to result in rod failure. However there hasn't been any methodology or a chart provided to apply this knowledge on to the individual patients that undergo the treatment. This study aims to fill in that gap.MethodThe parametric study was performed by varying the material properties of the disc, hence altering the axial stiffness of the scoliotic spine model. The stresses on the rod were found to increase with increased axial stiffness of the spine, and this resulted in the increase of required optimal frequency to achieve a factor of safety of two for growth rods.Results And ConclusionThe current study demonstrates the possibility of translating fundamental information from finite element modeling to the clinical arena, for mitigating the occurrence of growth rod fracture, i.e., establishing a relationship between optimal distraction interval and curve flexibility (determined using curve correction under gravity).Level Of EvidenceN/A.

11 keywords...

hide…