Ole T. Jensen - The Osteoperiosteal Flap: A Simplified Approach to Alveolar Bone Reconstruction

Maxillary deformities have been recognized and described for centuries, but the challenge to correct them through surgery in the anterior maxilla was not met until the turn of the century. Bold attempts to move the anterior maxilla were first made by Cohn-Stock,9 Wassmund,10 and Spanier,11 who were unaware of the biologic basis for the healing of such surgically created wounds. Analysis of Cohn-Stocks initial attempt to retroposition the anterior maxilla surgically indicates that he feared the consequences of such a procedure and attempted to avoid them by creating a greenstick fracture of the anterior maxilla through a transverse palatal incision; the retropo-sitioned maxilla subsequently relapsed.

When maxillary surgical procedures were introduced to the United States,1215 the rationale for use of the various surgical techniques for correcting dentofacial deformities was empirical.16 Basic questions concerning the healing of surgical wounds produced by maxillary osteotomies had not been investigated. Many surgeons believed that the maxilla healed by fibrous union. Others believed absolute stability was necessary. Devitalization of teeth and bone in the mobilized segments had been re-ported. Varying degrees of relapse subsequent to posterior maxillary osteotomy9 and total maxillary osteotomy were reported. The possibility that the maxilla could be successfully repositioned superiorly or inferiorly through surgery was doubted by many clinicians and scientists. The blood vessels necessary to maintain circulation to the mobilized bony segments and teeth had not been studied. Consequently, both one-stage and two-stage procedures (of empirical duration ranging between 2 and 8 weeks) were devised to prevent impairment of the vascular supply to the mobilized dentoalveolar segments.17

Fig 1-1b Midpalatal sagittal incision for palatal osteotomies. (Reprinted from Bell et al23 with permission.)

In 1962, animal and clinical investigations were initiated to delineate the biology of maxillary osteotomy wound healing. Since then, rabbits, dogs, monkeys, and baboons have been used as experimental models to investigate the revascularization and bone healing associated with various maxillary techniques.12,16,18,19 Macaca mulatta was usually selected as the experimental animal of choice because of its anatomic, physiologic, and dental similarities to the human. Because maxillary osteotomies are usually performed in adults, large male rhesus monkeys from 8 to 14 years of age and weighing an average of 9 kg, were chosen for study.

From 1962 to 1965, revascularization and bone healing were studied on animal models after clinical simulations of three variations of anterior maxillary osteotomy techniques10,14,20 (Fig 1-1) were performed via various flap designs to validate vascularity to the repositioned osseous segments.12,13,22 The animals were killed 1, 3, 6, and 24 weeks after surgery for microangiographic and histologic investigation.

Horizontal microangiogram demonstrating the vascular pattern of a control animal. A reticulated network of periodontal plexus encircles each tooth, composed of anastomosing blood vessels from the labial (facial), gingival, intra-alveolar, and apical vessels. (Reprinted from Bell et al21 with permission.)

Serial 1-mm transverse, sagittal, and horizontal tissue slices were cut from the specimens for microangiographic study, which were in turn cut into seven microscopic slices for histologic study. Microangiographic and histologic techniques demonstrated that intraosseous and intrapulpal circulation to the anterior maxillary segment was maintained when soft tissue was kept intact.12,22 Osteonecrosis was minimal and vascular ischemia was only transient when the anterior maxillary bone segment was pedicled to the labiobuccal mucoperiosteum, palatal mucoperiosteum (), or a combination of both. Osseous union between most of the sectioned segments occurred within 6 weeks without immobilization of the mandible.