Maxillary advancement in cleft patients by means of transantral distraction: development of a new type of distraction device and pilot study of its clinical application.

In a single-stage procedure, a maximal advancement of 10 to 12 mm can be achieved in noncleft patients after good mobilization of the separated upper jaw complex. The greater the distance through which the upper jaw is operatively advanced, however, the greater the resulting skeletal relapse.1 The blood vessels supplying the area and the soft tissue attached to them are elastic and together they exert a force pulling the upper jaw back toward its original position and relapse occurs.2–4 It is possible to decrease this tendency to a limited extent by means of plate osteosynthesis and/or interposition of an autologous bone block in the pterygomaxillary fissure.5 In patients with a cleft lip or palate that has previously been operated on, the situation is much less favorable. In this group of patients, the upper jaw is often not only markedly retrodisplaced, but also shows a clear deficit in the vertical dimension. In cleft patients who have already undergone multiple operations, scar tissue adds to the force leading to relapse that is exerted by the soft tissue and blood vessels.3 Scarring also makes intraoperative surgical mobilization considerably more difficult than in noncleft patients and increases the magnitude of relapse.3,6–8 After advancement of the upper jaw through large distances, the extent of relapse is considerable,1,3,9 leading to reoperation in over 10 percent of cases.10 In single-stage maxillary advancement in cleft patients, it is therefore necessary to carry out extensive overcorrection, even at the surgical planning stage. Not only does this make the end result less predictable, it also brings with it the risk of maxillary necrosis because the blood supply of the area in cleft patients can be inhibited as a result of scarring. Since 1992,11 attempts have been made to solve the problem of the lack of soft tissue and bone availability in the mouth, jaw, and facial area by means of distraction osteogenesis.12 A variety of distraction devices have been used both intraorally and extraorally.11,13–17 The relapse rate seems to be lower with these methods than with the conventional procedure.18,19 However, there are also problems associated with these distraction procedures. They can be summarized as follows. If the distractors are fixed intraorally to the outer surface of the maxilla, which is convex overall, the distance between them and the bone surface is relatively large. This in turn leads to space problems and peri-implant inflammation. Only in very few cases is it possible to attach a pair of distractors parallel and targeted with respect to their angle to the Frankfort horizontal plane. Extraorally fixed distractors have the disadvantage of relatively poor three-dimensional