THE USE OF THE COTREL-DUBOUSSET MODULAR C ONSTRUCT (2HS-1SH) FOR FIXATION OF COMMINUTED FRACTURES OF THE THORACOLUMBAR JUNCTION - A COMPARISON WITH OTHER CONSTRUCTS

Introduction The authors' objective was to study the anatomical and fu nctional results of an original construct using the Cotrel-Dubousset i nstrumentation. Material and methods This construct is called << Modul ar construct >> or << 2 H.S. - 1 S.H. >> fits up two vertebrae above t he fracture and a single below. So if the fracture is situated on the Ll level, a supra-laminar hook is set up on each side of T11, and two pedicular screws in T12 (2 H.S.). In the same way, a pedicular screw a nd an infra-laminar hook are set up on each side of L2 (1.S.H.). Two t ransverse bars connect together the right and the left rod. This retro spective work is based on the study of 24 patients who had a Thoraco-l umbar burst fracture according to Denis' classification, who were oper ated on in our Department, and started again to walk without external contention. All the patients had a postero-lateral bone graft. There w ere anterior arthrodesis performed. The average follow up was 4 years. This series was compared with a concomitant series of miscellaneous c onstructs realized by the same operators with the C.D. instrumentation . Results The average regional kyphosis angles went from 16.9-degrees in pre-operative to 3,9-degrees in post-operative, and 8-degrees at th e maximum follow up. The average vertebral kyphosis angles went from 1 8-degrees in pre-operative to 3,8-degrees in post-operative, and 6,3-d egrees at the maximum follow up. The miscellaneous constructs had poor er results. There were two severe infections, one early the other late . Discussion These results compared with the literature show that the 2 H.S. - 1 S.H. construct is a competitive one. We think that its mech anical qualities arise from adding systematically hooks at the ends of the construct. These hooks protect the screws during flexion and from pull out constraints.