One Herbert double-threaded compression screw fixation of displaced type II odontoid fractures.

Surgical treatment of type II odontoid fractures (OFs) has usually entailed C1-2 arthrodesis rather than fracture fixation. An alternative treatment of direct screw fixation is used to treat the fractures for preservation of atlantoaxial rotation. Type II OFs that cannot be completely reduced by close means are generally believed to be a contraindication for anterior screw fixation. Seven patients (group I) with displaced type II OFs that could be completely reduced were treated with fracture fixation by one 4.5-mm double-threaded compression screw and five patients (group II) with displaced type II OFs that could only be partially reduced were treated with fracture fixation by one 3.0-mm double-threaded compression screw. All patients had a minimum of 1-year follow-up. No major complications occurred. No loss of reduction occurred in group I patients. Group II patients had an average loss of reduction of 0.8 mm anterior displacement and 5 degrees anterior angulation. The overall rate of fracture union was 100%, and fracture resolution averaged 4.1 months. Ten patients had a normal range of cervical rotation, and there was no difference in preservation of cervical rotation between the two groups. Our results suggest that close reduction and compressive osteosynthesis by one double-threaded compression screw is an optimal method of treatment for displaced type II OFs that can be completely reduced and for some cases that can only be partially reduced. A 100% rate of fracture union and preservation of cervical rotation are the major advantages of this method. However, significant complications have been reported by other investigators. (ABSTRACT TRUNCATED AT 250 WORDS)