ONE HERBERT DOUBLE-THREADED COMPRESSION SCREW FIXATION OF DISPLACED TYPE-II ODONTOID FRACTURES

Surgical treatment of type II odontoid fractures (OFs) has usually ent ailed C1-2 arthrodesis rather than fracture fixation. An alternative t reatment of direct screw fixation is used to treat the fractures for p reservation of atlantoaxial rotation. Type II OFs that cannot be compl etely reduced by close means are generally believed to be a contraindi cation for anterior screw fixation. Seven patients (group I) with disp laced type II OFs that could be completely reduced were treated with f racture fixation by one 4.5-mm double-threaded compression screw and f ive patients (group II) with displaced type II OFs that could only be partially reduced were treated with fracture fixation by one 3.0-mm do uble-threaded compression screw. All patients had a minimum of 1-year follow-up. No major complications occurred. No loss of reduction occur red in group I patients. Group II patients had an average loss of redu ction of 0.8 mm anterior displacement and 5-degrees anterior angulatio n. The overall rate of fracture union was 100%, and fracture resolutio n averaged 4.1 months. Ten patients had a normal range of cervical rot ation, and there was no difference in preservation of cervical rotatio n between the two groups. Our results suggest that close reduction and compressive osteosynthesis by one double-threaded compression screw i s an optimal method of treatment for displaced type II OFs that can be completely reduced and for some cases that can only be partially redu ced. A 100% rate of fracture union and preservation of cervical rotati on are the major advantages of this method. However, significant compl ications have been reported by other investigators. The use of a metic ulous surgical technique is mandatory, and contraindications should be respected.