THE USE OF THE COTREL-DUBOUSSET MODULAR C ONSTRUCT (2H.S-1S.H.) FOR FIXATION OF COMMINUTED FRACTURES OF THE THORACOLUMBAR JUNCTION - A COMPARISON WITH OTHER CONSTRUCTS (VOL 80, PG 205, 1994)

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 ''Modula r construct'' or '' 2 H.S. - 1 S.H.'' fits up two vertebrae above the fracture and a single below. So if the fracture is situated on the L1 level, a supra-laminar hook is set up on each side of T11, and two ped icular screws in T12 (2 H.S.). In the same way, a pedicular screw and an infra-laminar hook are set up on each side of L2 (1.S.H.). Two tran sverse bars connect together the right and the left rod. This retrospe ctive work is based on the study of 24 patients who had a Thoraco-lumb ar burst fracture according to Denis'classification, who were operated on in our Department, and started again to walk without external cont ention. All the patients had a postero-lateral bone graft. There were no anterior arthrodesis performed. The average follow up was 4 years. This series was compared with a concomitant series of miscellaneous co nstructs realized by the same operators with the C.D. instrumentation. Results The average regional kyphosis angles went from 16.9-degrees i n pre-operative to 3,9-degrees in post-operative, and 8-degrees at the maximum follow up. The average vertebral kyphosis angles went from 18 -degrees in preoperative to 3,8-degrees in post-operative, and 6,3-deg rees at the maximum follow up. The miscellaneous constructs had poorer 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 mechan ical qualities arise from adding systematically hooks at the ends of t he construct. These hooks protect the screws during flexion and from p ull out constraints.