Management of delayed union and nonunion of maxillary osteotomies

J Oral Maxillofac

Surg

49 1039-i 044, 1990

Management of Delayed Union and Nonunion of Maxillary Osteotomies JOSEPH E. VAN SICKELS, DDS,* AND MYRON R. TUCKER, DDSt Delayed union and nonunion of maxillary osteotomies are unusual, but have been seen with a variety of surgical moves. Management of these problems can be divided into early and late therapy. Four cases are presented illustrating some of these methods of treatment.

Several other categories of midface abnormalities also may have a higher incidence of compromised postoperative healing. Patients with inferior maxillary repositioning have been shown to have vertical relapse ranging from 20% to 70% in the postoperative period.’ Quejada et al3 noted that over 50% of the relapse of maxillary osteotomies stabilized with wire fixation occurred during the period of maxillomandibular fixation (MMF), and the remaining relapse occurred within the first 6 months postoperatively. Relapse in vertical maxillary deficiency cases may be a result of increased biomechanical forces resulting from excessive stretch of the muscles and alteration of the grafted tissue through normal resorption and remodeling processes. These factors also may result in delayed healing or eventual nonunion. Maxillary advancements, when excessive, may result in large defects between regions of maxillary bone contact. Araujo et al9 noted increasing relapse with larger maxillary advancements and recommended that bone grafts be placed in the pterygoid plate region as a mechanical stop when the maxilla was advanced more than 6 mm. They did not address bony defects occurring in the anterior and lateral maxillary wall regions. These large bony gaps frequently heal with small bony bridges, with the remainder of the gap filled with dense fibrous tissue. Failure to form adequate bony bridges in the region where a large gap exists between two thin maxillary bony cortices may result also in delayed healing or nonunion. Even though these types of problems are most frequently associated with large advancements or inferior repositioning, superior maxillary repositioning, especially in those cases with a posterior component of movement, also may result in significant gaps and similar healing problems.5.‘0

Several articles have been written describing techniques and results of maxillary osteotomies.‘-6 Surgical modifications, stability, and esthetic change have been described in detail; however, little attention has been devoted to the management of delayed union or nonunion of such osteotomies. These complications have been seen in maxillary osteotomies stabilized with either wire osteosynthesis or rigid internal fixation and have occurred with a variety of surgical movements. The purpose of this article is to review possible causes of this problem and to discuss management. Several case examples will be discussed and their treatment reviewed. Etiologic

Factors

Among the factors contributing to delayed union or nonunion are underlying skeletal and soft-tissue deformities that may predispose to poor healing. Patients with cleft palate frequently present with horizontal and vertical maxillary deficiency, scarred palatal mucosa, and a compromised blood supply. Difficulty in mobilizing the maxilla and the potential for compromise of a tenuous vascular supply may complicate healing and lead to postoperative instability.5 * Professor, Department of Oral and Maxillofacial Surgery, University of Texas Health Science Center at San Antonio, TX. ? Associate Professor. University of North Carolina at Chapel Hill, Chapel Hill, NC. Address correspondence and reprint requests to Dr Van Sickels: Department of Oral and Maxillofacial Surgery, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78284-7908. Q 1990 geons

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Technical difficulties encountered during the operative procedure also may have a significant influence on postoperative bone healing. Excessive stretching of soft tissue, violation of vascular pedicles, fracture of bony segments, and poor stabilization obviously will impair postoperative healing. Postoperative infection also will further slow healing, particularly when accompanied by instability of the maxilla. Several factors related to postoperative care may impact on the healing of maxillary osteotomies. When a maxillary osteotomy is completed without a concomitant mandibular osteotomy, the osteotomy site is subjected to forces generated by an intact mandible. Suspension wiring must accompany osteosynthesis and MMF to minimize mandibular movement against the mobilized maxilla. Even when rigid fixation is used, careful attention must be given to the force placed on the maxilla in the postoperative period. Use of short-term MMF may result in some movement of the maxilla when it is wired to an intact or rigidly stabilized mandible during the period of immobilization. In the immediate postoperative period, elastic traction may be responsible for placing forces that eventually loosen bone screws and plates. Postoperative occlusal prematurities also may place excessive force in one region, causing a rocking motion and mobility of the entire maxilla. This may result from improperly constructed splints or from tooth movement that occurred during the postoperative period. Such tooth movement can result from the use of heavy elastics or unintentional bends placed in an edgewise wire during surgery. It is important to remember that long class II and class III, as well as straight vertical elastics, have some component of vertical pull. Use of these elastics may create some slight extrusion of individual tooth segments, particularly when a large stabilizing arch wire is not in place. Finally, the unwillingness of a patient to comply with postoperative instructions, including a soft diet and reduced jaw function, may compromise healing. Any systemic condition that may alter healing has an obvious potential to cause delayed union or nonunion. Diabetes, collagen, and vascular disease, osteoporosis, or a variety of other systemic illnesses may delay postoperative healing. Poor nutrition also may contribute to slow union of bony segments. Treatment Recognition of potential problem cases and prevention is the ideal treatment to avert delayed union or nonunion of maxillary osteotomies. Patients with

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cleft palates, particularly those in whom there will be large movements, should be carefully evaluated. It has been our experience that despite the use of rigid fixation, maxillary advancements in patients with cleft palates are unstable and need to be treated with additional forms of fixation and/or immobilization. Currently, we use bone plates combined with suspension wires and 6 weeks of immobilization in many of these cases. When large defects exist between bony walls after maxillary repositioning, serious consideration should be given to some type of grafting. Grafting has been advocated in the pterygomaxillary area; however, graft material also should be placed in large defects in the anterior and lateral maxillary wall areas. Use of rigid fixation techniques or wire osteosynthesis combined with suspension wires may help prevent immediate postoperative maxillary movement. During the postoperative period, careful attention must be given to the patient use of the jaws, occlusal interferences, and elastic forces placed on the maxilla. Even under ideal circumstances, minor movement may be detected in maxillary osteotomies weeks to months after an operation. This may occur even with rigid internal fixation techniques in which the maxilla appears to be extremely secure, with screws placed in strong bone at the time of surgery. When excessive mobility of the maxilla is detected, treatment should be instituted. Postoperative management can be divided into the early and late phases. When excessive maxillary mobility is detected in the immediate postoperative period, an evaluation exploring potential causes must be done. These causes include loss of softtissue pedicles or infection secondary to dental or nondental origin. When these have been ruled out, the next step is to carefully evaluate the patient under function. When occlusal abnormalities are detected, occlusal modification or splint alteration may be helpful in more evenly distributing occlusal forces. Heavy elastic therapy should be discontinued and the patient should be placed on a very soft diet and followed closely (see Case 1). It must be remembered that although forces such as those produced with class III elastics may help prevent posterior relapse of the maxilla, some extrusive force is also placed on the maxillary teeth. Frequently, a combination of occlusal alteration and decreased elastic wear will result in gradual stabilization of the maxilla. Late management usually involves returning the patient to surgery where the maxillary osteotomy is recreated and the maxilla restabilized. In most cases, this includes the use of autogenous or allogeneic grafting as well as the use of bone plates and

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possible additional fixation devices to aid in stabilization of the maxilla. Reoperation of the maxilla should be approached with a philosophy similar to that used in treating nonunions of mandibular fractures or osteotomies. The surgical approach should result in aggressive mobilization of the maxilla, adequately exposing all bony edges of the osteotomy on both the superior and inferior segments. All fibrous tissue must be aggressively removed from the areas of potential bone contact, In some cases, the bony edge should be freshened with a bur to further insure removal of small remnants of fibrous tissue. Several types of graft material may be used; however, it is our opinion that in the case of reoperation, autogenous grafting with either iliac crest or cranial bone results in the best chance for postoperative union. Report of Four Cases Case I A 22-year-old white woman previously underwent a Le Fort I osteotomy with approximately 5 mm of maxillary advancement and 4 mm of inferior repositioning. The gap was filled by an autogenous graft and the maxilla was stabilized with wires. She moved to another location 4 months after surgery. Initial evaluation revealed a minimally mobile maxilla, particularly in the anterior area, where slight posterior relapse of the maxilla appeared to have caused increased contact in the incisor area. This created a slight rocking motion on the maxilla. When the patient produced maximum intercuspation with occlusal clenching, the maxilla was pushed anteriorly. Pressure on the posterior maxilla produced relatively little vertical displacement. The patient was placed on a soft diet and all elastics were temporarily discontinued. A full-coverage occlusal

splint was constructed and cold-curing acrylic was placed posteriorly to provide contact over the molars and bicuspids to reduce excessive occlusal force on the anterior maxilla. Within 2 months, the maxillary movement was no longer detectable. The splint was worn for an additional 2 months, at which time the maxilla appeared to be consolidated. Finishing orthodontics was completed. Case 2 A 26-year-old woman underwent a Le Fort 1 maxillary impaction for vertical maxillary excess. Her maxilla was suspended with suspension wires and she was kept in fixation for 6 weeks. Nine months after surgery, her maxilla was grossly mobile and moved 1VGmm when she occluded. The central incisors did not show at rest (Fig 1A). A second surgery was planned. This consisted of a 5-mm downgraft with placement of autogenous iliac bone. At surgery, it was revealed that the maxilla was telescoped within itself, resulting in very little bony contact. The maxilla was stabilized with four bone plates and she was allowed to function immediately (Fig IS). No further movement occurred and the results were still stable 6 months after surgery. Case 3 A 4%year-old woman underwent a Le Fort I maxillary downgraft for horizontal and vertical maxillary deficiency. Four bone plates were used along with freezedried bone (Fig 2A). Three months after surgery the maxilla was noted to be mobile. Elastics were discontinued and a flat splint was constructed. At 6 months, the maxilla was still mobile and had impacted 4 mm, whereas originally it had been downgrafted 2 mm. The patient was returned to surgery on an outpatient basis. All four plates were removed and the anterior ones replaced. Suspension wires were used posteriorly (Fig 2B). Intraoperatively, it was noted that the freeze-dried bone had not consolidated and one of the anterior plates was fractured.

FIGURE I Radiographs of patient. A, Radiograph 9 months after first surgery. B, Postoperative plates and an autogenous graft.

radiographs after placement of bone

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FIGURE 2. Radiographs of patient. A, Postoperative radiograph showing use of four plates and freeze-dried bone grafts. B. New anterior plates and posterior suspension wires have been placed. C. Result of third surgery. Autogenous grafts, four plates, and suspension wires have been used for stabilization.

The patient’s maxilla appeared stable after the second surgery; however, mobility was again noted 2 months later. Splints and nonsurgical therapy again failed to achieve the desired results. She was returned to surgery a third time, where the maxilla was again mobilized. This time, fibrous tissue was removed, and she had four plates and suspension wires placed along with autogenous grafts. Her maxilla was not placed in fixation. It slowly consolidated after 4 months of splint therapy and a soft diet (Fig 2C). Case 4 A 35year-old white man underwent a segmental maxillary osteotomy and bilateral sagittal split osteotomy. The operation was complicated by an inability to fit the segments correctly into the splint, inability to stabilize the segments, excessive intraoperative bleeding, and insufficient stabilization during the postoperative period. When the patient was referred for further care, there was a severe anterior open bite, gross displacement of the right maxillary segment in the vertical direction, and a total vertical change of 14 mm from the preoperative position

(Fig 3). In addition to the gross malocclusion and functional difficulties, the lack of incisor exposure was of significant concern to the patient. The maxilla was grossly mobile to palpation at 7 months after surgery. At the time of the second surgery, mandibular osteotomies were completed first under the assumption that the segments could be repositioned and stabilized with large bone plates and that the maxilla could then be appropriately positioned against an intact mandible, avoiding the technical difficulties with doing the maxilla first. The maxilla was aggressively mobilized and all regions of fibrous tissue were removed. The anterior and left portion of the maxilla was down-grafted 15 mm using autogenous iliac crest bone. The anterior maxilla was stabilized with small bone plates. Because of the excessive bone resorption, it was impossible to place plates posteriorly without violating the roots of teeth, the infraorbital nerve region, and the infraorbital rim. Therefore, a rigid pin system was used for stabilization in the posterior maxilla. A 0.045-in buccal tube was embedded into each side of the splint before surgery. A 0.045-in stainless steel wire was then bent to lay passively against the anterior area of the zygomatic buttress after insertion into the buccal

VAN SICKELS AND TUCKER

FIGURE 3. A, Pretreatment cephalometric radiograph. B, Radiograph at the time of patient’s initial presentation. Note extreme resorption and vertical superior repositioning of the maxilla. C. Occlusion at time of initial presentation.

FIGURE 4.

A, View of maxilla with bone plates and vertical stabilizing pins in place. B, Postoperative

radiograph.

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tube. This was secured with a stainless steel screw (Fig 4). The patient was allowed to function immediately postoperatively with no maxillomandibular elastics. The maxilla consolidated rapidly and the vertical struts were removed 3 months postoperatively. Finishing orthodontics was completed in 3 months and the maxilla has remained stable.

Discussion

Fortunately, because of the rich blood the maxilla, delayed unions or nonunions

supply

to

were unSome cases are pose greater risk Recognition of the need for pro-

usual with maxillary osteotomies. more problematic, however, and for these types of complications. such difficult cases may prevent longed postoperative treatment. Early postoperative management may prevent more-severe problems at a later time. It has been our experience that discontinuing heavy elastic traction often results in consolidation of the maxilla within 2 to 4 weeks. Late therapy must include aggressive mobilization, removal of fibrous tissue, grafting, preferably with autogenous tissue, and application of rigid fixation.

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References 1. Bell WH, Manni C, Luhr H-G: Art and science of the Le Fort I down fracture. Int .I Adult Orthod Orthog Surg 3:23, 1988 2. Hiranaka DK, Kelly JP: Stability of simultaneous orthognathic surgery on the maxilla and mandible: Computer assisted cephalometric study. Int J Adult Orthod Orthog Surg 2: 193, 1987 3. Quejada JG. Bell WH, Kawamura H, et al: Skeletal stability after inferior maxillary repositioning. Int J Adult Orthod Orthog Surg 267, 1987 4. Skoczvlas LJ. Ellis E. Fonseca RJ. et al: Stabilitv of simultaneous maxillary intrusion and mandibular advancement: A comparison of rigid and nonrigid fixation techniques. J Oral Maxillofac Surg 46: 1056. 1988 5. Bays RO: Rigid stabilization system for maxillary osteotomies. J Oral Maxillofac Surg 43:60, 1985 6. Van Sickels JE, Jeter TS, Aragon SB: Rigid fixation of maxillary osteotomies: A preliminary report and technique article. Oral Surg Oral Med Oral Path01 60:262. 1985 7. Wolford LM, Hillard FW: The surgical orthodontic correction of vertical dentofacial deformities. J Oral Surg 39:883, 1981 8. Bell WH, Scheideman GB: Correction of vertical maxillary deficiency: Stability and soft tissue changes. J Oral Surg 39:666. 1981 9. Araujo A. Schendel SA, Wolford LM, et al: Total maxillary advancement with and without bone grafting. J Oral Surg 361849. 1978 10. LeBanc JP, Turvey TA, Epker BN: Results following simultaneous mobilization of the maxilla and mandible for correction of dentofacial deformities: Analysis of 100 consecutive patients. Oral Surg Oral Med Oral Path01 54:607. 1982