Fractures of the vertebral lamina associated with unifacet and bifacet cervical spine dislocations.

Unifacet and bifacet dislocations of the lower cervical spine are very common injuries. Occasionally these injuries may be associated with fractures of the lamina which, in the absence of computed tomography, are often discovered in theatre. The presence of a fracture of the lamina makes the standard posterior wiring and fusion biomechanically unstable even when the vertebra above is included. A retrospective study to assess the incidence of these fractures and their final outcome was undertaken. Forty-three patients operated on for cervical spine dislocations during the period June 1989 to December 1990 were analysed. Twelve were found to have associated lamina fractures. At final discharge 5 of the 12 patients had kyphosis due to translation, despite good peri-operative reduction. One patient had neurological deterioration, which improved after an anterior plating and fusion.