title: A comparative study of fixation techniques for type II fractures of the odontoid process.
abstract: Primary screw fixation of a Type II odontoid fracture or non-union is an attractive alternative to posterior atlanto-axial arthrodesis in that normal cervical motion can be maintained. Eight cervical cadaver spines, ranging in age from 17-90 years, were used for study. Type II fractures of the dens were created using an osteotome. Simulated fractures were fixed using one or two 3.5-mm bone screws. After testing each screw fixation technique, the screws were removed and a posterior C1-C2 brooks sublaminar wiring was performed using four 18-gauge wires with wooden blocks to simulate bone graft. No significant differences were found between bending and torsional stiffnesses for the one-screw and two-screw specimens. No significant differences were found between one- and two-screw fixation when compared with primary C1-C2 wiring in torsion. One- or two-screw fixation was as stiff as primary C1-C2 wiring in bending. One or two screws offers similar stability for fixation for a dens fracture. One- and two-screw fixation is at least as stiff as primary C1-C2 wiring in torsion and one- or two-screw fixation is stiffer than primary C1-C2 wiring in bending.
authors.affiliation: Orthopaedic Research Laboratories, University of Michigan, Ann Arbor.
authors.forename: G
authors.initials: G
authors.lastname: Graziano
authors.forename: C
authors.initials: C
authors.lastname: Jaggers
authors.forename: M
authors.initials: M
authors.lastname: Lee
authors.forename: W
authors.initials: W
authors.lastname: Lynch
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001863:Bone Screws; D001864:Bone Wires; D002102:Cadaver; D005593:Fracture Fixation, Internal / Q000379:methods*; D006801:Humans; D008875:Middle Aged; D009809:Odontoid Process / Q000293:injuries*; D016103:Spinal Fractures / Q000601:surgery*; D013314:Stress, Mechanical