Fixation of onlay bone grafts with lag screws.

A method is described of fastening bone segments to the mandible and maxilla by means of lag screws. The indications are discussed, as are the possible advantages of the procedure compared with fixation of bone grafts by wiring or by osteosynthesis plates. Indications include: 1. Fixation of bone segments at the lower border of the mandible when, after maximal displacement of the segments, the surface of contact between the mandible and the bone segment becomes too small. 2. Filling-in defects in the alveolar process, e.g. stabilising bone grafts for augmentation of the height of the alveolar ridge. 3. Fixation of fragments serving to bridge over mandibular defects. Within the stated range of indications lag screws appear to have the following advantages compared with wire fixation: a) more stable immobilisation of the grafts b) closer contact between graft and recipient surface through compression between the two; c) the possibility of easier removal of the screws compared with removal of wires. Within the range of indications lag screws appear to have the following advantages compared with bone graft fixation by means of osteosynthesis plates: a) The plate acts as a separating medium between graft and the soft tissue bed. b) The more tedious removal of plates is avoided with screws.