Rigid fixation and facial asymmetry.

The use of rigid fixation for the correction of facial asymmetry is in principle no different from its use in other forms of craniomaxillofacial deformity. The use of screws and plates demands more precise techniques than the use of wires. Attention to detail in passively fitting the plate to the defect and accurate insertion of the drill holes and screws enables the production of good occlusion and a symmetrical face. The precise osteotomies and bone grafts needed in the correction of all forms of skeletal asymmetry are as described for hemifacial microsomia or temporomandibular ankylosis. In a young child whose secondary dentition has not yet erupted it is not possible to insert screws, neither is the bone in a costochondral graft solid enough to permit screw fixation without the use of intermaxillary fixation. Therefore, rigid fixation can be used for osteotomies and bone grafts in patients whose main permanent dentition has erupted and in whom the cortex of the bone graft is strong enough to retain the screws against the pull of facial muscles.