Orthognatic surgery versus anterior maxillary distraction in maxillary hypoplasia
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). Since the early 2000s, distraction osteogenesis of the facial skeleton has become popular because of the ability to perform large maxillary advancement without the need for bone grafting. Staged maxillary advancement remains a predictable option for patients, but the ability to produce large advancements using distraction is attractive in those with marked retrusion. In others, a combined maxillary advancement and mandibular reduction can be performed to correct severe deformities after completion of growth.
A meta-analysis of literature from 1996 to 2003 by Cheung et al. on cleft maxillary osteotomy and distraction osteogenesis showed most patients who underwent conventional maxillary osteotomies were older (16 to 20 years) compared to those who had distraction (11 to 15 years). The mean advancement for both groups was similar but larger maximum advancement was achieved in the distraction group. The most commonly used system was the rigid external distractor (RED) device. They subsequently conducted a randomized, controlled study comparing maxillary distraction and orthognathic surgery in 29 nongrowing cleft patients. Intraoral distractors were used in 15 patients in the distraction group and routine miniplate fixation for the 14 patients in the orthognathic surgery group. Clinical morbidity and stability was assessed using a questionnaire and lateral cephalometric tracings, respectively. It was found that there was no significant difference in the clinical morbidities, but the maxillary movement in the distraction group was more stable than with orthognathic repositioning. Skeletal relapse was evident in the first 3 months following conventional cleft maxillary advancement.
Orthognathic surgery in the cleft patient is much more challenging than for the noncleft patient. Starting from anesthetic management to surgical postoperative care, several modifications are necessary for orthognathic surgery in the cleft individual. The presence of a deviated nasal septum or a pharyngeal flap may necessitate the use of a fiberoptic assisted intubation technique, or it may be necessary to pass the endotracheal tube over a more rigid tube or catheter. The vascularity of the labial and palatal mucoperiosteal tissues is invariably affected by previous surgical procedures for lip and palate repair. Drommer and Luhr demonstrated with the use of angiography that the greater palatine arteries were significantly smaller in 10 of 24 sides in 12 cleft patients prior to maxillary advancement. When surgical incisions are made to provide access for maxillary osteotomies, care should be taken to maintain a generous soft tissue pedicle. During down-fracture, the greater palatine arteries should be preserved if possible, and trauma to the palatal and buccal soft tissue pedicles should be avoided. Failure to do so may result in the loss of attached gingival tissues, bone, and teeth. The nasal mucosa and palatal mucosa are fused in the region of the cleft because of the primary palate repair. This tissue should be sharply incised close to the nasal floor just prior to the down-fracture. This is necessary to down-fracture and to adequately mobilize the maxilla. Mobilization of the maxilla after down-fracture is more difficult because of the palatal scar tissue or a pharyngeal flap. In some cases, release or division of the pharyngeal flap may be indicated to reposition the maxilla into the desired position. The primary palatal repair often results in more bone formation and stronger union at the pterygomaxillary junction. Use of a curved chisel to osteotomize directly through the maxillary tuberosities rather than the dense bone of the pterygomaxillary junction is helpful to complete this posterior osteotomy. Complete mobilization to achieve sufficient advancement requires progressive, careful stretching, as the scarred soft tissues are less compliant.
A meta-analysis of literature from 1996 to 2003 by Cheung et al. on cleft maxillary osteotomy and distraction osteogenesis showed most patients who underwent conventional maxillary osteotomies were older (16 to 20 years) compared to those who had distraction (11 to 15 years). The mean advancement for both groups was similar but larger maximum advancement was achieved in the distraction group. The most commonly used system was the rigid external distractor (RED) device. They subsequently conducted a randomized, controlled study comparing maxillary distraction and orthognathic surgery in 29 nongrowing cleft patients. Intraoral distractors were used in 15 patients in the distraction group and routine miniplate fixation for the 14 patients in the orthognathic surgery group. Clinical morbidity and stability was assessed using a questionnaire and lateral cephalometric tracings, respectively. It was found that there was no significant difference in the clinical morbidities, but the maxillary movement in the distraction group was more stable than with orthognathic repositioning. Skeletal relapse was evident in the first 3 months following conventional cleft maxillary advancement.
Orthognathic surgery in the cleft patient is much more challenging than for the noncleft patient. Starting from anesthetic management to surgical postoperative care, several modifications are necessary for orthognathic surgery in the cleft individual. The presence of a deviated nasal septum or a pharyngeal flap may necessitate the use of a fiberoptic assisted intubation technique, or it may be necessary to pass the endotracheal tube over a more rigid tube or catheter. The vascularity of the labial and palatal mucoperiosteal tissues is invariably affected by previous surgical procedures for lip and palate repair. Drommer and Luhr demonstrated with the use of angiography that the greater palatine arteries were significantly smaller in 10 of 24 sides in 12 cleft patients prior to maxillary advancement. When surgical incisions are made to provide access for maxillary osteotomies, care should be taken to maintain a generous soft tissue pedicle. During down-fracture, the greater palatine arteries should be preserved if possible, and trauma to the palatal and buccal soft tissue pedicles should be avoided. Failure to do so may result in the loss of attached gingival tissues, bone, and teeth. The nasal mucosa and palatal mucosa are fused in the region of the cleft because of the primary palate repair. This tissue should be sharply incised close to the nasal floor just prior to the down-fracture. This is necessary to down-fracture and to adequately mobilize the maxilla. Mobilization of the maxilla after down-fracture is more difficult because of the palatal scar tissue or a pharyngeal flap. In some cases, release or division of the pharyngeal flap may be indicated to reposition the maxilla into the desired position. The primary palatal repair often results in more bone formation and stronger union at the pterygomaxillary junction. Use of a curved chisel to osteotomize directly through the maxillary tuberosities rather than the dense bone of the pterygomaxillary junction is helpful to complete this posterior osteotomy. Complete mobilization to achieve sufficient advancement requires progressive, careful stretching, as the scarred soft tissues are less compliant.
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