Mandibular distraction lengthening in the severely hypoplastic mandible: a problematic case with tongue aplasia.

Distraction lengthening is a technique that was initially developed for correction of lower limb length discrepancies. It has recently been adapted to maxillofacial problems and has gained increasing popularity in this application. This report illustrates the principles involved in mandibular distraction lengthening and offers possible solutions to potentially limiting clinical problems. First, conventional technique dictates that a distinct periosteal sleeve is necessary for distraction osteogenesis to occur. However, in this case, distraction was performed through an area of scar tissue in which the native periosteum was destroyed. The ability to extend the use of the technique of distraction successfully to suboptimal clinical situations may broaden the indications for its use. Second, fixator instability is a potentially common problem in these cases because of the forces involved in distraction osteogenesis and the duration of the process. However, mechanical rigidity is essential consolidation (typically requiring twice as long as the distraction phase). Fixator instability can be successfully salvaged during the mineralization phase of bony healing through the use of an onlay corticocancellous bone "plate," which resorbs as the distraction gap gains strength. This report highlights one of the main advantages of the distraction process: the expansion of the soft-tissue matrix of the face.