PULLOUT STRENGTH OF DIFFERENT DISTAL TERMINAL FIXATION CONSTRUCTS IN THORACOLUMBAR SPINE SURGERY: AN IN VITRO BIOMECHANICAL STUDY

BackgroundWhile the biomechanical properties of trans-pedicular screws have proven to be superior in the lumbar spine, little is known concerning pullout strength of trans-pedicle screws in comparison to different distal terminal constructs like sublaminar hooks alone, trans pedicular screws with sublaminar hooks and clow hooks alone in the thoracolumbar spine surgery. In vitro biomechanical pullout testing was performed to evaluate the axial pullout strength of four different distal terminal constructs in thoracolumbar spine surgery.Methods32 fresh-frozen lamb spines were used. The lamb spines were divided into four groups, each group is composed of eight lamb spine cadavers with a different distal fixation pattern was used to terminate the construct at L1. (Group 1) trans-pedicular screws alone, (Group 2) sublaminar hooks alone, (Group 3) trans-pedicular screws augmented with a sublaminar hooks via a domino connector and (Group 4) clow hooks alone.ResultsThe average pullout strength of group 1 was 927N,...