- Email: [email protected]
A New Technique for Intraoral Maxillary Distraction: A Case Report
536
INTRAORAL MAXILLARY DISTRACTION
28. Cohen D, Granda-Ricart MC: Giant cell reparative granuloma of the base of the skull in a 4-month-old infant-CT findings. Pediatr Radiol 23:319, 1993 29. Nemoto Y, Inoue Y, Tashiro T, et al: Central giant cell granuloma of the temporal bone. Am J Neuroradiol 16:982, 1995 30. Maruno M, Yoshimine T, Kubo T, et al: A case giant cell reparative granuloma of the petrous bone. Demonstration of the proliferative component. Surg Neurol 48:64, 1997 31. Knoduei I, Rowley H, Farrel M, et al: An unusual cause for tinnitus. Ir Med J 94:312, 2001 32. Lin J, Zhong DR, Liu LF, et al: Giant cell reparative granuloma of the temporal bone. Acta Otolaryngol 121:523, 2001
33. De Lange J, Rosenberg AJ, Van den Akker HP, et al: Treatment of central giant cell of the jaw with calcitonin. Int J Oral Maxillofac Surg 28:372, 1999 34. Pogrel MA, Regezi JA, Harris ST, et al: Calcitonin treatment for central giant cell granulomas of the mandible. Report of two cases. J Oral Maxillofac Surg 57:848, 1999 35. Rajeevan NS, Soumithran CS: Intralesional corticosteroid injection for central giant cell granuloma: A case report. Int J Oral Maxillofac Surg 27:1145, 1999 36. Kaban LB, Mulliken JB, Ezekowitz A: Antiangiogenic therapy of recurrent giant cell tumor of the mandible with interferon alpha-2a. Pediatrics 103:1145, 1999
J Oral Maxillofac Surg 64:536-542, 2006
A New Technique for Intraoral Maxillary Distraction: A Case Report Stuart Super, DMD,* Jonathan E. Schecter, DDS,† and Richard D. Bae, DDS‡ Distraction osteogenesis has become a major surgical technique aiding in the promotion of bone formation. The driving force behind distraction osteogenesis lies in its ability to stimulate new bone formation between 2 osteotomized segments of bone gradually separating under tension.1-3 It was not until 1992, however, that distraction osteogenesis for the craniofacial complex came into use.4 In its earliest craniofacial applications, distraction osteogenesis was limited to treating deficient mandibles in children with hemifacial microsomia. Successful advancements have been made that allowed for the treatment of the maxilla with both predictability and stability.5-7 As with the original mandibular distraction appliances, the maxillary extraoral appliances used were esthetically unappealing as well as difficult for the patient to manage.8 Recently, more inconspicuous intraoral distraction appliances have been developed and used with varying
*Chief, Department of Oral and Maxillofacial Surgery, Lenox Hill Hospital, New York, NY; Associate Professor, Department of Oral and Maxillofacial Surgery, New York University College of Dentistry, New York, NY. †Orthognathic Fellow, Department of Oral and Maxillofacial Surgery, Lenox Hill Hospital, New York, NY. ‡Chief Resident, Department of Oral and Maxillofacial Surgery, NYU/Bellevue Hospital Center, New York, NY. Address correspondence and reprint requests to Dr Super: 6 East 78th St, New York, NY 10021; e-mail: [email protected] © 2006 American Association of Oral and Maxillofacial Surgeons
0278-2391/06/6403-0029$32.00/0 doi:10.1016/j.joms.2005.11.021
success. We present a case report using a variation of an intraoral maxillary distraction appliance.
Materials and Methods PRESURGICAL TECHNIQUE
The appliance designed was used for a 21-year-old man who presented with a surgically repaired unilateral cleft lip and palate, as well as a moderately hypoplastic maxilla. The patient had been previously treated using conventional orthognathic surgery in which a maxillary advancement was performed. In addition, the patient underwent the repair of a chronic oronasal fistula. Because of the vast amount of fibrous scar tissue created from the cleft lip and palate repair, the patient exhibited a complete relapse of the maxillary advancement within 12 months postoperatively. Therefore, it was decided that distraction osteogenesis would be used to treat the hypoplastic maxilla. At first we proposed to use the rigid external distractor system (KLS-Martin LP, Tuttlingen, Germany).9,10 However, because of the patient’s reluctance to wear the device while going to college, we instead decided to use the intraoral Antwerp transsinusoidal maxillary distractor (KLS-Martin LP)11 for treatment. Unfortunately, because of insufficient thickness and strength of the patient’s maxillary sinus wall, placement of these distractors could not be facilitated. These events propagated the development of an intraoral distraction appliance that would exhibit stability, predictability, vector control, and patient tolerance.
SUPER, SCHECTER, AND BAE
537
FIGURE 1. Intraoral maxillary distraction appliance adapted to stereolithographic model. Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
The distraction appliance we designed was fabricated using a titanium alloy in the laboratories of KLS Martin LP (Fig 1). The appliance consisted of 2 parts: an inner (distraction) bar containing a central screw to allow for 10⫹ mm of distraction and an outer (anchorage) bar (Fig 2). The inner bar can be secured to either an overdenture or to an existing orthodontic appliance. The outer bar of the appliance was fixed to the zygomatic bone to provide adequate anchorage to withstand the force of distraction. The 2 parts were connected by inserting the anchorage bar into the slot of the distraction bar. Activation would be accomplished by turning the screw on the distraction bar. Each turn allowed the maxilla to be advanced by 0.5 mm. Therefore, 2 complete turns of the activation key was performed to achieve the desired 1 mm distraction per day. The appliance was designed so that the screw and the bars met and were accessible at the junction of the upper and lower lip at rest. Alginate impressions of both arches were taken. The models were then mounted via a face bow record transfer onto a semi-adjustable hinge articulator in centric relation. Using the maxillary model, a full coverage acrylic splint with bilateral posterior buccal flanges was fabricated. The inner distraction bar was then fixated to the splint (Fig 3). Using 3-dimensional computerized tomography, a stereolithographic model of the patient’s craniofacial complex was fabricated. This allowed for precise determination of the position, as well as custom adaptation of the outer bar’s bilateral cloverleaf meshwork to the zygomatic buttress pre-surgically. Once satisfied with the placement of the outer bar, 2 mm ⫻ 7 mm surgical screws were used to fixate it to the model. The acrylic splint was then fit to the teeth of
FIGURE 2. Intraoral maxillary distraction appliance. A, Inner (distraction) bar (above) with outer (anchorage) bar (below). B, Appliance fully assembled. Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
FIGURE 3. Inner distraction bar fixated to prefabricated full coverage maxillary acrylic splint. Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
538
INTRAORAL MAXILLARY DISTRACTION
matic bone. After completion of the pilot holes, both the anchorage bar and splint housing the distraction bar were removed. A high Le Fort I osteotomy was then performed and the maxilla was mobilized. The anchorage and distraction bars were then replaced and connected. The previously prepared pilot holes enabled us to quickly relocate the original position of the anchorage bar. Using 1.5 mm ⫻ 7 mm surgical screws, the anchorage
FIGURE 4. A, Outer anchorage bar stabilized to zygomatic bone (arrows). B, Inner distraction bar with acrylic splint stabilized to maxillary arch and connected to outer anchorage bar. Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
the stereolithographic model so as to allow for appropriate placement of the inner distraction bar. Once the final determination of the position of inner distraction bar was achieved, the bilateral posterior wings of the distraction bar were adapted to the buccal posterior flanges of the acrylic splint and secured to it with acrylic and 1.5 mm ⫻ 5 mm surgical screws (Fig 3). These techniques described above saved significant time during the surgical procedure. SURGICAL TECHNIQUE
The patient was placed under general anesthesia using nasoendotracheal intubation. Local anesthesia was administered along our usual buccal incision line for a Le Fort I osteotomy. A full-thickness mucoperiosteal flap was reflected exposing both the right and left zygomatic buttresses. At this point, the acrylic splint/distraction bar was tried in the patient’s mouth. The anchorage bar was then inserted into the housing slot of the distraction bar. This pre-osteotomy technique enabled us to accurately determine the exact location and fit the anchorage bar’s meshwork to each zygomatic buttress, thus replicating the position from the stereolithographic model. Using the cloverleaf meshwork as a guide, pilot holes for placement of surgical screws were then prepared into the zygo-
FIGURE 5. A, Frontal facial view of patient postoperatively. B, Intraoral view of the distraction appliance. Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
539
SUPER, SCHECTER, AND BAE
the operating room to have the distraction appliance removed.
Results
FIGURE 6. Maxillary bone at time of distraction appliance removal. Note the new bone regenerate (arrow). Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
The removal of the distraction appliance was uneventful. New bone regenerate created by the distraction process was observed (Fig 6). The surgical wound site was closed and postoperatively the patient was placed in class III elastic traction (Fig 7). A comparative lateral cephalometric analysis was performed (Fig 8). Most noticeably, 11-month postoperative occlusal photographs showed there was an 8.2 mm increase in overjet from ⫺6.9 mm to 1.3 mm (Fig 9). Postoperative photographs were taken to display the positive soft tissue changes that occurred to the patient (Fig 10). Finalization of the patient’s occlusion will be achieved with postoperative orthodontic therapy.
bar was secured to the zygomatic bone (Fig 4). The distraction appliance was activated approximately 1 mm and then closed to visually ensure that the appliance was functioning properly. The surgical wound site was closed in the usual fashion and the standard protocol for maxillary distraction followed: a 5-day latency period followed by a distraction period at a rate of 1 mm per day for 10 days. Upon completion of the distraction period, the newly distracted segment was maintained for an additional 8 weeks to allow for new bone formation (ie, consolidation phase). During this process, the distraction appliance was well tolerated by the patient (Fig 5). On completion of the consolidation phase, the patient was brought back to
FIGURE 7. Postoperative intraoral view after distraction appliance removal with class III elastic traction in place.
FIGURE 8. Lateral cephalometric radiographs: A, preoperative and B, postoperative.
Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
540
INTRAORAL MAXILLARY DISTRACTION
FIGURE 9. Intraoral occlusion views: A–C, preoperative, and D–F, postoperative. Note increase in the overjet. Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
Discussion Use of distraction osteogenesis for the craniofacial complex has ranged from the repair of minor bony defects of the alveolar process to the treatment of severe craniofacial deformities. Distraction osteogenesis of the maxilla, in particular, has been used to treat severe hypoplasia, as seen in syndromic patients such as Cruzons and Aperts syndrome, as well as patients with moderate hypoplasia who exhibit a high relapse potential (eg, patients with fibrous scar tissue from a surgically repaired cleft lip and palate). The first maxillary distraction appliance exhibiting success was an extraoral appliance anchored into the cranium (Rigid External Distraction [RED] System; KLS-Martin LP).6,7 This appliance provided significant stability, precise multi-planar vector control, as well as a theoretical unlimited potential for distraction. However, the ap-
pliance can be quite cumbersome for the patient. Therefore, while this appliance is advantageous for severe hypoplastic cases in which a Le Fort II or Le Fort III osteotomy is indicated, patients exhibiting a more moderate hypoplasia of the maxilla in which a more conservative approach is required (eg, Le Fort I osteotomy), the use of such an appliance is oftentimes unnecessary. Intraoral maxillary distraction appliances were primarily developed in an attempt to provide more patient comfort, thereby increasing patient acceptance. Two commonly used appliances are the Zurich maxillary distractor (KLS-Martin LP)8 and the trans-sinusoidal distractor (KLS-Martin LP).11 Although both appliances have proved to be successful, each displays significant clinical limitations. For instance, both distraction appliances have separate right and left com-
541
SUPER, SCHECTER, AND BAE
FIGURE 10. Frontal and lateral facial views: A, B, preoperative, and C, D, postoperative. Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
ponents. Because of this design, parallelism of these components must be verified during placement for the appliance to function properly. Placement of the Zurich distraction appliance is oftentimes limited because of the presence of tooth buds or roots of the maxillary molars. In addition, the quality of bone of the maxillary sinus wall can limit the facilitation of the trans-sinusoidal appliance.
The intraoral maxillary distraction appliance used in this case was specifically designed to address some of these limitations. The anchorage bar was developed to be fixated bilaterally to the zygomatic buttresses. Because of the dense quality of bone routinely found in this region, maximum anchorage was provided for the distraction appliance. Also, by designing the distraction bar as 1 component that bilaterally
542 spanned the maxilla, parallelism was not an issue. Furthermore, by fixating the distraction bar to the dentition via an acrylic splint, any possible damage to developing tooth buds or roots of the maxillary molars was avoided. There were, however, certain clinical limitations that were encountered with this appliance. For instance, this appliance did not exhibit multi-planar vector control as displayed by the rigid external distractor device. The rate-limiting factor regarding the total amount of distraction osteogenesis that can be achieved by this appliance is the anchorage bar interfering with the anterior maxilla. In addition, a substantial amount of gingival irritation was observed on removal of the acrylic splint. Finally, although there was an excellent amount of tolerance exhibited by the patient overall, there was an issue concerning the position of the anchorage bar in relation to the upper lip. Currently, these issues are being addressed and modifications will be incorporated into the next generation of this appliance. Overall, this distraction appliance proved very successful in this case for the treatment of the patient’s moderate maxillary hypoplasia. This appliance offers a treatment option where a unidirectional advancement of 8 mm to 12 mm is required. Acknowledgment The authors acknowledge the generous support and collaboration of KLS-Martin LP in the development of this device.
INTRAORAL MAXILLARY DISTRACTION
References 1. Codivilla A: On the means of lengthening in the lower limbs, muscles and tissues which are shortened through deformity. Am J Orthop Surg 2:353, 1905 2. Illizarov GA: The tension-stress effect on the genesis and growth of tissues: Part 1. The influence of stability of fixation and soft-tissue preservation. Clin Orthop 238:249, 1989 3. Illizarov GA: The tension-stress effect on the genesis and growth of tissues: Part 2. The influence of the rate and frequency of distraction. Clin Orthop 239:263, 1989 4. McCarthy JG, Schreiber J, Karp N, et al: Lengthening the human mandible by gradual distraction. Plast Reconstr Surg 89:1, 1992 5. Molina F, Ortiz Monasterio F, de la Paz Aguilar M, et al: Maxillary distraction: Aesthetic and functional in cleft lip-palate and prognathic patients during mixed dentition. Plast Reconstr Surg 101:951, 1999 6. Polley JW, Figueroa AA: Management of severe maxillary deficiency in childhood and adolescence through distraction osteogenesis with an external, adjustable, rigid distraction device. J Craniofac Surg 8:181, 1997 7. Polley JW, Figueroa AA: Rigid external distraction: its application in cleft maxillary deformities. Plast Reconstr Surg 102: 1360, 1998 8. Weinzweig J, Baker SB, Mackay GJ, et al: Immediate versus delayed midface distraction in a primate model using a new intraoral internal device. Plast Reconstr Surg 109:1600, 2002 9. Figueroa AA, Polley JW: Management of severe cleft maxillary deficiency with distraction osteogenesis: Procedure and results. Am J Orthod Dentofac Orthop 115:1, 1999 10. Harada K, Yoshiyuki B, Ohyama, K, et al: Maxillary distraction osteogenesis for cleft lip and palate children using an external, adjustable, rigid distraction device: A report of 2 cases. J Oral Maxillofac Surg 59:1492, 2001 11. Nadjmi N: Mid-facial distraction with an intra-oral trans-sinusoidal distractor. 3rd Int Congr Craniofac Maxillofac Distrac 3:419, 2001
INTRAORAL MAXILLARY DISTRACTION
28. Cohen D, Granda-Ricart MC: Giant cell reparative granuloma of the base of the skull in a 4-month-old infant-CT findings. Pediatr Radiol 23:319, 1993 29. Nemoto Y, Inoue Y, Tashiro T, et al: Central giant cell granuloma of the temporal bone. Am J Neuroradiol 16:982, 1995 30. Maruno M, Yoshimine T, Kubo T, et al: A case giant cell reparative granuloma of the petrous bone. Demonstration of the proliferative component. Surg Neurol 48:64, 1997 31. Knoduei I, Rowley H, Farrel M, et al: An unusual cause for tinnitus. Ir Med J 94:312, 2001 32. Lin J, Zhong DR, Liu LF, et al: Giant cell reparative granuloma of the temporal bone. Acta Otolaryngol 121:523, 2001
33. De Lange J, Rosenberg AJ, Van den Akker HP, et al: Treatment of central giant cell of the jaw with calcitonin. Int J Oral Maxillofac Surg 28:372, 1999 34. Pogrel MA, Regezi JA, Harris ST, et al: Calcitonin treatment for central giant cell granulomas of the mandible. Report of two cases. J Oral Maxillofac Surg 57:848, 1999 35. Rajeevan NS, Soumithran CS: Intralesional corticosteroid injection for central giant cell granuloma: A case report. Int J Oral Maxillofac Surg 27:1145, 1999 36. Kaban LB, Mulliken JB, Ezekowitz A: Antiangiogenic therapy of recurrent giant cell tumor of the mandible with interferon alpha-2a. Pediatrics 103:1145, 1999
J Oral Maxillofac Surg 64:536-542, 2006
A New Technique for Intraoral Maxillary Distraction: A Case Report Stuart Super, DMD,* Jonathan E. Schecter, DDS,† and Richard D. Bae, DDS‡ Distraction osteogenesis has become a major surgical technique aiding in the promotion of bone formation. The driving force behind distraction osteogenesis lies in its ability to stimulate new bone formation between 2 osteotomized segments of bone gradually separating under tension.1-3 It was not until 1992, however, that distraction osteogenesis for the craniofacial complex came into use.4 In its earliest craniofacial applications, distraction osteogenesis was limited to treating deficient mandibles in children with hemifacial microsomia. Successful advancements have been made that allowed for the treatment of the maxilla with both predictability and stability.5-7 As with the original mandibular distraction appliances, the maxillary extraoral appliances used were esthetically unappealing as well as difficult for the patient to manage.8 Recently, more inconspicuous intraoral distraction appliances have been developed and used with varying
*Chief, Department of Oral and Maxillofacial Surgery, Lenox Hill Hospital, New York, NY; Associate Professor, Department of Oral and Maxillofacial Surgery, New York University College of Dentistry, New York, NY. †Orthognathic Fellow, Department of Oral and Maxillofacial Surgery, Lenox Hill Hospital, New York, NY. ‡Chief Resident, Department of Oral and Maxillofacial Surgery, NYU/Bellevue Hospital Center, New York, NY. Address correspondence and reprint requests to Dr Super: 6 East 78th St, New York, NY 10021; e-mail: [email protected] © 2006 American Association of Oral and Maxillofacial Surgeons
0278-2391/06/6403-0029$32.00/0 doi:10.1016/j.joms.2005.11.021
success. We present a case report using a variation of an intraoral maxillary distraction appliance.
Materials and Methods PRESURGICAL TECHNIQUE
The appliance designed was used for a 21-year-old man who presented with a surgically repaired unilateral cleft lip and palate, as well as a moderately hypoplastic maxilla. The patient had been previously treated using conventional orthognathic surgery in which a maxillary advancement was performed. In addition, the patient underwent the repair of a chronic oronasal fistula. Because of the vast amount of fibrous scar tissue created from the cleft lip and palate repair, the patient exhibited a complete relapse of the maxillary advancement within 12 months postoperatively. Therefore, it was decided that distraction osteogenesis would be used to treat the hypoplastic maxilla. At first we proposed to use the rigid external distractor system (KLS-Martin LP, Tuttlingen, Germany).9,10 However, because of the patient’s reluctance to wear the device while going to college, we instead decided to use the intraoral Antwerp transsinusoidal maxillary distractor (KLS-Martin LP)11 for treatment. Unfortunately, because of insufficient thickness and strength of the patient’s maxillary sinus wall, placement of these distractors could not be facilitated. These events propagated the development of an intraoral distraction appliance that would exhibit stability, predictability, vector control, and patient tolerance.
SUPER, SCHECTER, AND BAE
537
FIGURE 1. Intraoral maxillary distraction appliance adapted to stereolithographic model. Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
The distraction appliance we designed was fabricated using a titanium alloy in the laboratories of KLS Martin LP (Fig 1). The appliance consisted of 2 parts: an inner (distraction) bar containing a central screw to allow for 10⫹ mm of distraction and an outer (anchorage) bar (Fig 2). The inner bar can be secured to either an overdenture or to an existing orthodontic appliance. The outer bar of the appliance was fixed to the zygomatic bone to provide adequate anchorage to withstand the force of distraction. The 2 parts were connected by inserting the anchorage bar into the slot of the distraction bar. Activation would be accomplished by turning the screw on the distraction bar. Each turn allowed the maxilla to be advanced by 0.5 mm. Therefore, 2 complete turns of the activation key was performed to achieve the desired 1 mm distraction per day. The appliance was designed so that the screw and the bars met and were accessible at the junction of the upper and lower lip at rest. Alginate impressions of both arches were taken. The models were then mounted via a face bow record transfer onto a semi-adjustable hinge articulator in centric relation. Using the maxillary model, a full coverage acrylic splint with bilateral posterior buccal flanges was fabricated. The inner distraction bar was then fixated to the splint (Fig 3). Using 3-dimensional computerized tomography, a stereolithographic model of the patient’s craniofacial complex was fabricated. This allowed for precise determination of the position, as well as custom adaptation of the outer bar’s bilateral cloverleaf meshwork to the zygomatic buttress pre-surgically. Once satisfied with the placement of the outer bar, 2 mm ⫻ 7 mm surgical screws were used to fixate it to the model. The acrylic splint was then fit to the teeth of
FIGURE 2. Intraoral maxillary distraction appliance. A, Inner (distraction) bar (above) with outer (anchorage) bar (below). B, Appliance fully assembled. Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
FIGURE 3. Inner distraction bar fixated to prefabricated full coverage maxillary acrylic splint. Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
538
INTRAORAL MAXILLARY DISTRACTION
matic bone. After completion of the pilot holes, both the anchorage bar and splint housing the distraction bar were removed. A high Le Fort I osteotomy was then performed and the maxilla was mobilized. The anchorage and distraction bars were then replaced and connected. The previously prepared pilot holes enabled us to quickly relocate the original position of the anchorage bar. Using 1.5 mm ⫻ 7 mm surgical screws, the anchorage
FIGURE 4. A, Outer anchorage bar stabilized to zygomatic bone (arrows). B, Inner distraction bar with acrylic splint stabilized to maxillary arch and connected to outer anchorage bar. Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
the stereolithographic model so as to allow for appropriate placement of the inner distraction bar. Once the final determination of the position of inner distraction bar was achieved, the bilateral posterior wings of the distraction bar were adapted to the buccal posterior flanges of the acrylic splint and secured to it with acrylic and 1.5 mm ⫻ 5 mm surgical screws (Fig 3). These techniques described above saved significant time during the surgical procedure. SURGICAL TECHNIQUE
The patient was placed under general anesthesia using nasoendotracheal intubation. Local anesthesia was administered along our usual buccal incision line for a Le Fort I osteotomy. A full-thickness mucoperiosteal flap was reflected exposing both the right and left zygomatic buttresses. At this point, the acrylic splint/distraction bar was tried in the patient’s mouth. The anchorage bar was then inserted into the housing slot of the distraction bar. This pre-osteotomy technique enabled us to accurately determine the exact location and fit the anchorage bar’s meshwork to each zygomatic buttress, thus replicating the position from the stereolithographic model. Using the cloverleaf meshwork as a guide, pilot holes for placement of surgical screws were then prepared into the zygo-
FIGURE 5. A, Frontal facial view of patient postoperatively. B, Intraoral view of the distraction appliance. Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
539
SUPER, SCHECTER, AND BAE
the operating room to have the distraction appliance removed.
Results
FIGURE 6. Maxillary bone at time of distraction appliance removal. Note the new bone regenerate (arrow). Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
The removal of the distraction appliance was uneventful. New bone regenerate created by the distraction process was observed (Fig 6). The surgical wound site was closed and postoperatively the patient was placed in class III elastic traction (Fig 7). A comparative lateral cephalometric analysis was performed (Fig 8). Most noticeably, 11-month postoperative occlusal photographs showed there was an 8.2 mm increase in overjet from ⫺6.9 mm to 1.3 mm (Fig 9). Postoperative photographs were taken to display the positive soft tissue changes that occurred to the patient (Fig 10). Finalization of the patient’s occlusion will be achieved with postoperative orthodontic therapy.
bar was secured to the zygomatic bone (Fig 4). The distraction appliance was activated approximately 1 mm and then closed to visually ensure that the appliance was functioning properly. The surgical wound site was closed in the usual fashion and the standard protocol for maxillary distraction followed: a 5-day latency period followed by a distraction period at a rate of 1 mm per day for 10 days. Upon completion of the distraction period, the newly distracted segment was maintained for an additional 8 weeks to allow for new bone formation (ie, consolidation phase). During this process, the distraction appliance was well tolerated by the patient (Fig 5). On completion of the consolidation phase, the patient was brought back to
FIGURE 7. Postoperative intraoral view after distraction appliance removal with class III elastic traction in place.
FIGURE 8. Lateral cephalometric radiographs: A, preoperative and B, postoperative.
Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
540
INTRAORAL MAXILLARY DISTRACTION
FIGURE 9. Intraoral occlusion views: A–C, preoperative, and D–F, postoperative. Note increase in the overjet. Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
Discussion Use of distraction osteogenesis for the craniofacial complex has ranged from the repair of minor bony defects of the alveolar process to the treatment of severe craniofacial deformities. Distraction osteogenesis of the maxilla, in particular, has been used to treat severe hypoplasia, as seen in syndromic patients such as Cruzons and Aperts syndrome, as well as patients with moderate hypoplasia who exhibit a high relapse potential (eg, patients with fibrous scar tissue from a surgically repaired cleft lip and palate). The first maxillary distraction appliance exhibiting success was an extraoral appliance anchored into the cranium (Rigid External Distraction [RED] System; KLS-Martin LP).6,7 This appliance provided significant stability, precise multi-planar vector control, as well as a theoretical unlimited potential for distraction. However, the ap-
pliance can be quite cumbersome for the patient. Therefore, while this appliance is advantageous for severe hypoplastic cases in which a Le Fort II or Le Fort III osteotomy is indicated, patients exhibiting a more moderate hypoplasia of the maxilla in which a more conservative approach is required (eg, Le Fort I osteotomy), the use of such an appliance is oftentimes unnecessary. Intraoral maxillary distraction appliances were primarily developed in an attempt to provide more patient comfort, thereby increasing patient acceptance. Two commonly used appliances are the Zurich maxillary distractor (KLS-Martin LP)8 and the trans-sinusoidal distractor (KLS-Martin LP).11 Although both appliances have proved to be successful, each displays significant clinical limitations. For instance, both distraction appliances have separate right and left com-
541
SUPER, SCHECTER, AND BAE
FIGURE 10. Frontal and lateral facial views: A, B, preoperative, and C, D, postoperative. Super, Schecter, and Bae. Intraoral Maxillary Distraction. J Oral Maxillofac Surg 2006.
ponents. Because of this design, parallelism of these components must be verified during placement for the appliance to function properly. Placement of the Zurich distraction appliance is oftentimes limited because of the presence of tooth buds or roots of the maxillary molars. In addition, the quality of bone of the maxillary sinus wall can limit the facilitation of the trans-sinusoidal appliance.
The intraoral maxillary distraction appliance used in this case was specifically designed to address some of these limitations. The anchorage bar was developed to be fixated bilaterally to the zygomatic buttresses. Because of the dense quality of bone routinely found in this region, maximum anchorage was provided for the distraction appliance. Also, by designing the distraction bar as 1 component that bilaterally
542 spanned the maxilla, parallelism was not an issue. Furthermore, by fixating the distraction bar to the dentition via an acrylic splint, any possible damage to developing tooth buds or roots of the maxillary molars was avoided. There were, however, certain clinical limitations that were encountered with this appliance. For instance, this appliance did not exhibit multi-planar vector control as displayed by the rigid external distractor device. The rate-limiting factor regarding the total amount of distraction osteogenesis that can be achieved by this appliance is the anchorage bar interfering with the anterior maxilla. In addition, a substantial amount of gingival irritation was observed on removal of the acrylic splint. Finally, although there was an excellent amount of tolerance exhibited by the patient overall, there was an issue concerning the position of the anchorage bar in relation to the upper lip. Currently, these issues are being addressed and modifications will be incorporated into the next generation of this appliance. Overall, this distraction appliance proved very successful in this case for the treatment of the patient’s moderate maxillary hypoplasia. This appliance offers a treatment option where a unidirectional advancement of 8 mm to 12 mm is required. Acknowledgment The authors acknowledge the generous support and collaboration of KLS-Martin LP in the development of this device.
INTRAORAL MAXILLARY DISTRACTION
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