Correction of Maxillomandibular Disharmonies
The individual with a cleft deformity will usually exhibit maxillarv retrusion and’ a transverse maxillary constriction resulting from the cicatricial contraction of previous’ surgeries. In many instances the associated alocclusion is beyond the scope of orthodontic treatment alone.,In
these cases orthognathic surgery similar ·to the procedures outlined in Chapter 25′ are indicated to correct ‘the underlying skeletal alrelationships.
However, some differences exist in the technical aspects of maxillary surgery because of the other deformities and scarring that are present in the maxillas of cleft-afflicted individuals. ‘In general, total maxillary
osteotomies are necessary to advance and sometimes widen the maxilla. Closure of some of the space in the alveolar cleft area by bringing the alveolus of the cleft side anteriorly is also performed in several instances.
These ‘latter procedures necessitate the segmentation of the maxilla, which, because of the cleft’s nature, usual1y already has occurred. The differences between the cleftafflicted patient and a non-cleft-afflicted patient, however,
are the scar present across the palate and the decreased blood supply to the maxilla. Scarrrorn previous surgeries makes widening of the very difficult.
frequently excision of some of this tissue is necessary, The clinician should try to be diligent and to maintain as much mucoperiosteum to the maxilla as possible because of the poor blood supply that the cleft maxilla receives.
Care must also be taken not to create another oronasal fistula. If the alveolar cleft ha-d not been grafted -previously, this can be do e in the same operation. In bilateral clefts, however, the blood supply to the prolabia I segment is very poor. It may be more prudent in these instances to perform the alveolar cleft grafts first and then perform a one-piece maxillary osteotomy after sufficient time has passed for rcvascularization of t he prolabia! segment. O!lC problem.faced by the patient with a cleft palate
when rnaxillarv advancement procedures are planned is the effect this -may have on -the velopharyngeal mechanism. When the maxilla is brought forward, the soft palate is also drawn .forward. A patient’s preoperative
marginal competence of the velopharyngeal mechanism may become incompetent in the postoperative period. It is very difficult to determine which patients will have this problem. Because of the possibility of this incompetence, however, secondary palatal or pharyngeal surgical rocedures “to increase velopharyngeal competence are discussed with the patient. These procedures can be performed later if necessar