- Email: [email protected]
Maxillary Distraction Osteogenesis Using the Intraoral Distractors and the Full-Covered Tooth-Supported Maxillary Splint
J Oral Maxillofac Surg 65:813-817, 2007
Maxillary Distraction Osteogenesis Using the Intraoral Distractors and the Full-Covered Tooth-Supported Maxillary Splint Seiji Iida, DDS, PhD,* Mikihiko Kogo, DDS, PhD,† Tomonao Aikawa, DDS, PhD,‡ Tomotake Masuda, DDS,§ Natsuko Yoshimura, DDS,储 and Satoshi Adachi, DDS, PhD¶ Recent numerous clinical reports described well the benefit of distraction osteogenesis for facial bone deformities.1 For cases of severe midfacial retrusion, it may be said that distraction osteogenesis in combination with Le Fort osteotomy is now one of the standard procedures. Distraction osteogenesis for the maxilla can be divided into 2 groups according to its anchorage: the external distractor, such as the RED system (Rigid External Distraction system: KLS-Martin LP, Tuttlingen, Germany),1-7 and the intraoral distractor. In the latter group, many intraoral devices are involved, and the cylindrical distractor, such as Zurich Pediatric Maxillary Distractor (KLS-Martin LP) is one of the well-known intraoral distractors for maxillary advancement. Indeed, although these distractors have some benefit, quite a smaller number of cases using internal distractors has been reported1,7-14 in comparison with cases treated by the RED system.1-7 One of
the most considerable technical reasons may be the difficulty in positioning the 2 intraoral distractors in parallel15 with a correct direction, and some attempts have been made to solve this problem.11,16 Additionally, we often noticed difficulties in securing the intraoral distractors on a suitable area of maxillary segment because of morphological abnormality of maxillary bone. In this report, we show a technique of distraction osteogenesis using the intraoral cylindrical distraction device with a full-covered maxillary splint, which contributes to determining the 3-dimensional direction of maxillary advancement during the operation, and which can be also used as the anchor of the maxillary segment for distraction osteogenesis.
Technical Note MAXILLARY SPLINT
Before the operation, the cast model must be prepared for the full covered maxillary splint. This splint was made according to the following procedures: the 1-mm laminate sheet (ERUKODUR) was heated and compressed against a cast model by the Erkopress200E (ERKODENT, Pfalzgrafenweiler, Germany). Two flattened resin plates were attached on both sides, and oriented parallel to the planned horizontal direction of maxillary advancement. On the surfaces of these plates, the vertical direction for distraction is marked according to the previous cepharometric and dental cast model analysis. On the palatal surface of the splint, an adequate miniplate was adapted and secured by self-curing acrylic resin to reinforce the mechanical strength of the plate, and this plate will be used to fix the splint with the palatal bone by transmucosal screw insertion.
*Assistant Professor, First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan. †Director and Professor, First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan. ‡Research Assistant, First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan. §Resident, First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan. 储Resident, First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan. ¶Private Practice, Adachi Orthodontic Clinic, Mino-o, Osaka, Japan. Address correspondence and reprint requests to Dr Iida: The First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan; e-mail: [email protected]
OPERATION PROCEDURE
© 2007 American Association of Oral and Maxillofacial Surgeons
Prior to maxillary osteotomy, the splint was set on the upper teeth tightly and the intraoral distractors
0278-2391/07/6504-0038$32.00/0 doi:10.1016/j.joms.2005.10.062
813
814 were adapted to fit on both sides of the zygomatic buttress according to the direction marked on the plates, parallel to the surface of the plate. At this point, the 6-hole miniplate part of the cylindrical distractor (Zurich Pediatric Maxillary Distractor; KLSMartin LP) must be kept in position parallel to the cylindrical rod in order to treat this miniplate part as a director of the rod. This procedure allowed us to keep the position of distractor rods parallel without any effort. After the temporal securing of the distractor on the bone surface of the zygomatic buttress with screws, the part of the miniplate was fixed with splint by molding the self-curing acrylic resin (Fig 1A). After removal of the screws at the zygomatic buttress on both sides, the splint and 2 distractors can be removed as one piece. Le Fort I maxillary osteotomy was performed according to routine procedure. After the down fracture of the maxillary segment, the splint with distractors was set again and this splint was fixed with each tooth by 0.4-mm stainless wire and the transmucosal insertions of self-tapping screws through the holes of the miniplate on the palatal surface of the splint (Fig 1B). Then the distractors secured with the zygomatic buttress again. To obtain enough stability of the splint, the splint was reinforced by additional molding of the self-curing acrylic resin on the surface of the splint, mainly at the palatal area, if necessary. After advancement of the maxilla by approximately 5 mm using the distractor, the mucoperiosteal flap was sutured. Distraction was initiated 7 days after the operation at a rate of 1 mm per day. The distraction was continued until planned advancement was completed. After completion of distraction, the distractor and splint were left in place for 2 weeks. The following rigid fixation using miniplates was performed with the removal of the distractors with the maxillary splint. Delaire masks should be used continuously to prevent the resisting force of the surrounding soft tissue from the operation until 4 weeks after removal of the distractors.
Report of a Case A 21-year-old Japanese male presented to our clinic with a referral from a private orthodontic clinic complaining of maxillary retrusion. He suffered craidocranial dysostosis and he was undergoing orthodontic treatment because of the delayed eruption of permanent teeth. Preoperative cepharometric analysis showed maxillary retrusion and mandibular protrusion, and we made a plane of the maxillary distraction osteogenesis before the mandibular osteotomy. The maxillary advancement was estimated as 12 mm forward and 3 mm downward parallel to the midline of the face. According to his demand, the maxillary distraction by intraoral distractors (Zurich Paediatric Maxillary Distractor) was planned.
MAXILLARY DISTRACTION OSTEOGENESIS
FIGURE 1. The model schema of maxillary distraction osteogenesis using the intraoral cylindrical distractor and a full covered maxillary splint. A, Lateral view. B, Palatal view after securing the splint by self-tapping bone screw insertion. The parallel resin plates set beside the splint, showing the planed direction of the distraction osteogenesis. The cylindrical rod of the distractor should be positioned according to this direction, and the miniplate is fixed by molding the self-curing acrylic resin, after temporally securing the distractor with the maxillary buttress. The miniplate on the palatal surface of the splint contributes to reinforce the stability of the splint during the distraction period by securing the self-tapping screws’ insertion into palatal bone. Iida et al. Maxillary Distraction Osteogenesis. J Oral Maxillofac Surg 2007.
Preoperative radiographic examinations showed the small distance between the zygomatic buttress and the maxillary alveolar bone with many impacted teeth. The difficulty of securing the distractor at the maxillary segment had been forecasted according to the results of these examinations, and we performed the distraction osteogenesis according to the procedure described above. The operation was performed without any mishap on August 25, 2003 (Fig 2). The distraction started at 7 days postoperatively and elongation of 1 mm/day was started. Although some changes in direc-
IIDA ET AL
FIGURE 2. Cephalometric radiograph immediately after the first operation. The internal distractors were placed between the zygomatic buttress and the tooth, because of less height of the maxillary alveolar process. The wires at the anterior part were used for securing the splint with teeth and the 2 long screws located vertically to the palatal bone were used for direct fixation of the splint with the palatal bone transmucously.
815 distractor is the same as the external distractor, which requires anchorage against the distraction in and out of the oral cavity; the RED system is now the most common external distractor.1-7 The RED system has many benefits for cases of severe maxillary deformity because this system can change the vector of distraction and has less limitation of the length of distraction. However, wearing the external anchorage equipment on lateral temporal areas causes psychological stress for patients during the distraction and retention periods, and requires special care for preventing traumatic force on this equipment.17,18 On the other hand, it seems that the reports of cases using intraoral devices are somehow fewer,1,7,10,14 although there is no doubt that these procedures have some benefits. One of the reasons for less wide usage of intraoral distractors is that it is considered difficult to place 2 devices for correct direction16 and to parallel the devices on both sides when 2 distractors had to be used. Paralleling the distractors is the most important process in the procedure using rigid internal distractors,15 and the rigid fixation of 2 devices in a warped direction can easily cause the screws to be loosened and failure of distraction osteogenesis. Therefore, surgeons should always have some ideas for securing
Iida et al. Maxillary Distraction Osteogenesis. J Oral Maxillofac Surg 2007.
tion of both distractors were found on radiographs during the distraction (Fig 3), the maxillary segment was continuously moved and finally, the maxillary segment was elongated 13 mm forward and 2 mm downward. Fifteen days after completion of the distraction, the distractor was removed with the splint, and the distracted segment was secured to the maxillary bone by 4 L-shaped miniplates under general anesthesia on October 1, 2003. The postoperative course was not eventful and the maxilla is positioned at the same place without any recurrence (Figs 4, 5). In the future, we will perform bilateral sagittal splitting ramus osteotomy for correction of the remaining mandibular prognathism, when the alignment for this osteotomy is finished.
Discussion There is no doubt that the distraction osteogenesis has become one of the important treatments for facial skeletal deformity, and recent numerous reports showed well the benefit of this treatment.1 The distraction osteogenesis can be divided into 2 procedures according to the type of device, one is an intraoral distractor and the other is an external distractor. For the maxillary distraction, an extraoral
FIGURE 3. Cepalometric lateral radiograph at completion of distraction osteogenesis. The maxillary incisors were positioned 13 mm anterior and 3 mm downward compared with the position before distraction osteogenesis. Both distractors changed their directions during the distraction osteogenesis. Iida et al. Maxillary Distraction Osteogenesis. J Oral Maxillofac Surg 2007.
816
MAXILLARY DISTRACTION OSTEOGENESIS
parallel distractors.11,16 In our procedure, the 3-dimensional directions for the maxillary advancement were previously drawn on the side-plates on each side of the splint and easily realize the direction during the operation. It may be said that this splint is always helpful in any procedure using intraoral distractors in the positioning and securing process. As less maxillary height and many incompletely erupted upper teeth make it difficult to drive the screws for fixation of the internal distractor on the lateral alveolar region, in our presented case we had to fix the distractors with the dental arch level. Orthodontic equipment set on the dental arch are often used for anchorage of the distractor in the movable segment in tooth-borne distraction osteogenesis, but the teeth are likely to dislocate if movements of the maxillary bone segment is interfered with. In our procedure, the full covered maxillary splint secured with the palatal bone by transmucosal screws, may contribute to preventing this complication and also may contribute to widening the indication of maxillary distraction osteogenesis using an intraoral distractor for the patients who have less erupted teeth. According to reported procedures,4,5,11,17,18 the internal distractors should be left in place for 12 weeks after completion of the distraction to obtain enough FIGURE 5. Intraoral finding before and after maxillary distraction osteogenesis. A, Before maxillary advancement by distraction osteogenesis. B, One year after distraction osteogenesis. Iida et al. Maxillary Distraction Osteogenesis. J Oral Maxillofac Surg 2007.
osseous healing in the distraction gap. However, it is difficult to keep the splint in place for such a long period in our procedure, because of the problem of oral hygiene. Therefore, our procedure requires the earlier removal of the distractors following rigid plate fixations of the distracted segment. Indeed, the immediate or earlier rigid fixation of bone segments has not been recommended in the past, but the recent study by Wong et al19 showed that enough stability could be obtained by immediate rigid fixation after completion of distraction. In the presented case, the recurrence was not found after miniplate fixation and the incisors positioned on the planned place on the previous cepharometric analysis. However, continuous suspension by the face mask for stabilizing the surgical result after removal of the distractor is necessary.
References FIGURE 4. Cephalometric lateral radiograph taken 6 months after the final operation. The maxillary segment was positioned in the same place at the period of completion of the distraction osteogensesis. Iida et al. Maxillary Distraction Osteogenesis. J Oral Maxillofac Surg 2007.
1. Swennen G, Schliephake H, Dempf R, et al: Craniofacial distraction osteogenesis: A review of the literature: Part 1: Clinical studies. Int J Oral Maxillofac Surg 30:89, 2001 2. Hierl T, Hemprich A: A novel modular retention system for midfacial distraction osteogenesis. Br J Oral Maxillofac Surg 38:623, 2000
IIDA ET AL 3. Kitai N, Kawasaki K, Yasuda Y, et al: Rigid external distraction osteogenesis for a patient with maxillary hypoplasia and oligodontia. Cleft Palate Craniofac J 40:207, 2003 4. Ko EW, Figueroa AA, Guyette TW, et al: Velopharyngeal changes after maxillary advancement in cleft patients with distraction osteogenesis using a rigid external distraction device: A 1-year cephalometric follow-up. J Craniofac Surg 10: 312, 1999 5. Krimmel M, Cornelius CP, Roser M, et al: External distraction of the maxilla in patients with craniofacial dysplasia. J Craniofac Surg 12:458, 2001 6. Wen-Ching Ko E, Figueroa AA, Polley JW: Soft tissue profile changes after maxillary advancement with distraction osteogenesis by use of a rigid external distraction device: A 1-year follow-up. J Oral Maxillofac Surg 58:959, 2000 7. Wiltfang J, Hirschfelder U, Neukam FW, et al: Long-term results of distraction osteogenesis of the maxilla and midface. Br J Oral Maxillofac Surg 40:473, 2002 8. Emparanza A, Zwetyenga N, Siberchicot F, et al: La distraction osseuse dans les hypoplasies du maxillaire. A propos de 14 cas cliniques. Ann Chir Plast Esthet 46:285, 2001 9. Karakasis D, Hadjipetrou L: Advancement of the anterior maxilla by distraction (case report). J Craniomaxillofac Surg 32:150, 2004 10. Kessler P, Wiltfang J, Schultze-Mosgau S, et al: Distraction osteogenesis of the maxilla and midface using a subcutaneous device: Report of four cases. Br J Oral Maxillofac Surg 39:13, 2001
817 11. Nakagawa K, Ueki K, Takatsuka S, et al: A device for determining the position of intraoral distractors for protracting the maxilla. J Craniomaxillofac Surg 31:234, 2003 12. Wiltfang J, Kessler P: Endoscopically assisted Le Fort I osteotomy to correct transverse and sagittal discrepancies of the maxilla. J Oral Maxillofac Surg 60:1142, 2002 13. Samchukov ML, Cope JB, Cherkashin AM: The effect of sagittal orientation of the distractor on the biomechanics of mandibular lengthening. J Oral Maxillofac Surg 57:1214, 1999 14. Li KK, Powell NB, Riley RW, et al: Distraction osteogenesis in adult obstructive sleep apnea surgery: A preliminary report. J Oral Maxillofac Surg 60:6, 2002 15. Yamaji KE, Gateno J, Xia JJ, et al: New internal Le Fort I distractor for the treatment of midface hypoplasia. J Craniofac Surg 15:124, 2004 16. Watzinger F, Wanschitz F, Rasse M, et al: Computer-aided surgery in distraction osteogenesis of the maxilla and mandible. Int J Oral Maxillofac Surg 28:171, 1999 17. Le BT, Eyre JM, Wehby MC, et al: Intracranial migration of halo fixation pins: A complication of using an extraoral distraction device. Cleft Palate Craniofac J 38:401, 2001 18. Rieger J, Jackson IT, Topf JS, et al: Traumatic cranial injury sustained from a fall on the rigid external distraction device. J Craniofac Surg 12:237, 2001 19. Wong GB, Padwa BL: Le Fort I soft tissue distraction: A hybrid technique. J Craniofac Surg 13:572, 2002
Maxillary Distraction Osteogenesis Using the Intraoral Distractors and the Full-Covered Tooth-Supported Maxillary Splint Seiji Iida, DDS, PhD,* Mikihiko Kogo, DDS, PhD,† Tomonao Aikawa, DDS, PhD,‡ Tomotake Masuda, DDS,§ Natsuko Yoshimura, DDS,储 and Satoshi Adachi, DDS, PhD¶ Recent numerous clinical reports described well the benefit of distraction osteogenesis for facial bone deformities.1 For cases of severe midfacial retrusion, it may be said that distraction osteogenesis in combination with Le Fort osteotomy is now one of the standard procedures. Distraction osteogenesis for the maxilla can be divided into 2 groups according to its anchorage: the external distractor, such as the RED system (Rigid External Distraction system: KLS-Martin LP, Tuttlingen, Germany),1-7 and the intraoral distractor. In the latter group, many intraoral devices are involved, and the cylindrical distractor, such as Zurich Pediatric Maxillary Distractor (KLS-Martin LP) is one of the well-known intraoral distractors for maxillary advancement. Indeed, although these distractors have some benefit, quite a smaller number of cases using internal distractors has been reported1,7-14 in comparison with cases treated by the RED system.1-7 One of
the most considerable technical reasons may be the difficulty in positioning the 2 intraoral distractors in parallel15 with a correct direction, and some attempts have been made to solve this problem.11,16 Additionally, we often noticed difficulties in securing the intraoral distractors on a suitable area of maxillary segment because of morphological abnormality of maxillary bone. In this report, we show a technique of distraction osteogenesis using the intraoral cylindrical distraction device with a full-covered maxillary splint, which contributes to determining the 3-dimensional direction of maxillary advancement during the operation, and which can be also used as the anchor of the maxillary segment for distraction osteogenesis.
Technical Note MAXILLARY SPLINT
Before the operation, the cast model must be prepared for the full covered maxillary splint. This splint was made according to the following procedures: the 1-mm laminate sheet (ERUKODUR) was heated and compressed against a cast model by the Erkopress200E (ERKODENT, Pfalzgrafenweiler, Germany). Two flattened resin plates were attached on both sides, and oriented parallel to the planned horizontal direction of maxillary advancement. On the surfaces of these plates, the vertical direction for distraction is marked according to the previous cepharometric and dental cast model analysis. On the palatal surface of the splint, an adequate miniplate was adapted and secured by self-curing acrylic resin to reinforce the mechanical strength of the plate, and this plate will be used to fix the splint with the palatal bone by transmucosal screw insertion.
*Assistant Professor, First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan. †Director and Professor, First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan. ‡Research Assistant, First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan. §Resident, First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan. 储Resident, First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan. ¶Private Practice, Adachi Orthodontic Clinic, Mino-o, Osaka, Japan. Address correspondence and reprint requests to Dr Iida: The First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan; e-mail: [email protected]
OPERATION PROCEDURE
© 2007 American Association of Oral and Maxillofacial Surgeons
Prior to maxillary osteotomy, the splint was set on the upper teeth tightly and the intraoral distractors
0278-2391/07/6504-0038$32.00/0 doi:10.1016/j.joms.2005.10.062
813
814 were adapted to fit on both sides of the zygomatic buttress according to the direction marked on the plates, parallel to the surface of the plate. At this point, the 6-hole miniplate part of the cylindrical distractor (Zurich Pediatric Maxillary Distractor; KLSMartin LP) must be kept in position parallel to the cylindrical rod in order to treat this miniplate part as a director of the rod. This procedure allowed us to keep the position of distractor rods parallel without any effort. After the temporal securing of the distractor on the bone surface of the zygomatic buttress with screws, the part of the miniplate was fixed with splint by molding the self-curing acrylic resin (Fig 1A). After removal of the screws at the zygomatic buttress on both sides, the splint and 2 distractors can be removed as one piece. Le Fort I maxillary osteotomy was performed according to routine procedure. After the down fracture of the maxillary segment, the splint with distractors was set again and this splint was fixed with each tooth by 0.4-mm stainless wire and the transmucosal insertions of self-tapping screws through the holes of the miniplate on the palatal surface of the splint (Fig 1B). Then the distractors secured with the zygomatic buttress again. To obtain enough stability of the splint, the splint was reinforced by additional molding of the self-curing acrylic resin on the surface of the splint, mainly at the palatal area, if necessary. After advancement of the maxilla by approximately 5 mm using the distractor, the mucoperiosteal flap was sutured. Distraction was initiated 7 days after the operation at a rate of 1 mm per day. The distraction was continued until planned advancement was completed. After completion of distraction, the distractor and splint were left in place for 2 weeks. The following rigid fixation using miniplates was performed with the removal of the distractors with the maxillary splint. Delaire masks should be used continuously to prevent the resisting force of the surrounding soft tissue from the operation until 4 weeks after removal of the distractors.
Report of a Case A 21-year-old Japanese male presented to our clinic with a referral from a private orthodontic clinic complaining of maxillary retrusion. He suffered craidocranial dysostosis and he was undergoing orthodontic treatment because of the delayed eruption of permanent teeth. Preoperative cepharometric analysis showed maxillary retrusion and mandibular protrusion, and we made a plane of the maxillary distraction osteogenesis before the mandibular osteotomy. The maxillary advancement was estimated as 12 mm forward and 3 mm downward parallel to the midline of the face. According to his demand, the maxillary distraction by intraoral distractors (Zurich Paediatric Maxillary Distractor) was planned.
MAXILLARY DISTRACTION OSTEOGENESIS
FIGURE 1. The model schema of maxillary distraction osteogenesis using the intraoral cylindrical distractor and a full covered maxillary splint. A, Lateral view. B, Palatal view after securing the splint by self-tapping bone screw insertion. The parallel resin plates set beside the splint, showing the planed direction of the distraction osteogenesis. The cylindrical rod of the distractor should be positioned according to this direction, and the miniplate is fixed by molding the self-curing acrylic resin, after temporally securing the distractor with the maxillary buttress. The miniplate on the palatal surface of the splint contributes to reinforce the stability of the splint during the distraction period by securing the self-tapping screws’ insertion into palatal bone. Iida et al. Maxillary Distraction Osteogenesis. J Oral Maxillofac Surg 2007.
Preoperative radiographic examinations showed the small distance between the zygomatic buttress and the maxillary alveolar bone with many impacted teeth. The difficulty of securing the distractor at the maxillary segment had been forecasted according to the results of these examinations, and we performed the distraction osteogenesis according to the procedure described above. The operation was performed without any mishap on August 25, 2003 (Fig 2). The distraction started at 7 days postoperatively and elongation of 1 mm/day was started. Although some changes in direc-
IIDA ET AL
FIGURE 2. Cephalometric radiograph immediately after the first operation. The internal distractors were placed between the zygomatic buttress and the tooth, because of less height of the maxillary alveolar process. The wires at the anterior part were used for securing the splint with teeth and the 2 long screws located vertically to the palatal bone were used for direct fixation of the splint with the palatal bone transmucously.
815 distractor is the same as the external distractor, which requires anchorage against the distraction in and out of the oral cavity; the RED system is now the most common external distractor.1-7 The RED system has many benefits for cases of severe maxillary deformity because this system can change the vector of distraction and has less limitation of the length of distraction. However, wearing the external anchorage equipment on lateral temporal areas causes psychological stress for patients during the distraction and retention periods, and requires special care for preventing traumatic force on this equipment.17,18 On the other hand, it seems that the reports of cases using intraoral devices are somehow fewer,1,7,10,14 although there is no doubt that these procedures have some benefits. One of the reasons for less wide usage of intraoral distractors is that it is considered difficult to place 2 devices for correct direction16 and to parallel the devices on both sides when 2 distractors had to be used. Paralleling the distractors is the most important process in the procedure using rigid internal distractors,15 and the rigid fixation of 2 devices in a warped direction can easily cause the screws to be loosened and failure of distraction osteogenesis. Therefore, surgeons should always have some ideas for securing
Iida et al. Maxillary Distraction Osteogenesis. J Oral Maxillofac Surg 2007.
tion of both distractors were found on radiographs during the distraction (Fig 3), the maxillary segment was continuously moved and finally, the maxillary segment was elongated 13 mm forward and 2 mm downward. Fifteen days after completion of the distraction, the distractor was removed with the splint, and the distracted segment was secured to the maxillary bone by 4 L-shaped miniplates under general anesthesia on October 1, 2003. The postoperative course was not eventful and the maxilla is positioned at the same place without any recurrence (Figs 4, 5). In the future, we will perform bilateral sagittal splitting ramus osteotomy for correction of the remaining mandibular prognathism, when the alignment for this osteotomy is finished.
Discussion There is no doubt that the distraction osteogenesis has become one of the important treatments for facial skeletal deformity, and recent numerous reports showed well the benefit of this treatment.1 The distraction osteogenesis can be divided into 2 procedures according to the type of device, one is an intraoral distractor and the other is an external distractor. For the maxillary distraction, an extraoral
FIGURE 3. Cepalometric lateral radiograph at completion of distraction osteogenesis. The maxillary incisors were positioned 13 mm anterior and 3 mm downward compared with the position before distraction osteogenesis. Both distractors changed their directions during the distraction osteogenesis. Iida et al. Maxillary Distraction Osteogenesis. J Oral Maxillofac Surg 2007.
816
MAXILLARY DISTRACTION OSTEOGENESIS
parallel distractors.11,16 In our procedure, the 3-dimensional directions for the maxillary advancement were previously drawn on the side-plates on each side of the splint and easily realize the direction during the operation. It may be said that this splint is always helpful in any procedure using intraoral distractors in the positioning and securing process. As less maxillary height and many incompletely erupted upper teeth make it difficult to drive the screws for fixation of the internal distractor on the lateral alveolar region, in our presented case we had to fix the distractors with the dental arch level. Orthodontic equipment set on the dental arch are often used for anchorage of the distractor in the movable segment in tooth-borne distraction osteogenesis, but the teeth are likely to dislocate if movements of the maxillary bone segment is interfered with. In our procedure, the full covered maxillary splint secured with the palatal bone by transmucosal screws, may contribute to preventing this complication and also may contribute to widening the indication of maxillary distraction osteogenesis using an intraoral distractor for the patients who have less erupted teeth. According to reported procedures,4,5,11,17,18 the internal distractors should be left in place for 12 weeks after completion of the distraction to obtain enough FIGURE 5. Intraoral finding before and after maxillary distraction osteogenesis. A, Before maxillary advancement by distraction osteogenesis. B, One year after distraction osteogenesis. Iida et al. Maxillary Distraction Osteogenesis. J Oral Maxillofac Surg 2007.
osseous healing in the distraction gap. However, it is difficult to keep the splint in place for such a long period in our procedure, because of the problem of oral hygiene. Therefore, our procedure requires the earlier removal of the distractors following rigid plate fixations of the distracted segment. Indeed, the immediate or earlier rigid fixation of bone segments has not been recommended in the past, but the recent study by Wong et al19 showed that enough stability could be obtained by immediate rigid fixation after completion of distraction. In the presented case, the recurrence was not found after miniplate fixation and the incisors positioned on the planned place on the previous cepharometric analysis. However, continuous suspension by the face mask for stabilizing the surgical result after removal of the distractor is necessary.
References FIGURE 4. Cephalometric lateral radiograph taken 6 months after the final operation. The maxillary segment was positioned in the same place at the period of completion of the distraction osteogensesis. Iida et al. Maxillary Distraction Osteogenesis. J Oral Maxillofac Surg 2007.
1. Swennen G, Schliephake H, Dempf R, et al: Craniofacial distraction osteogenesis: A review of the literature: Part 1: Clinical studies. Int J Oral Maxillofac Surg 30:89, 2001 2. Hierl T, Hemprich A: A novel modular retention system for midfacial distraction osteogenesis. Br J Oral Maxillofac Surg 38:623, 2000
IIDA ET AL 3. Kitai N, Kawasaki K, Yasuda Y, et al: Rigid external distraction osteogenesis for a patient with maxillary hypoplasia and oligodontia. Cleft Palate Craniofac J 40:207, 2003 4. Ko EW, Figueroa AA, Guyette TW, et al: Velopharyngeal changes after maxillary advancement in cleft patients with distraction osteogenesis using a rigid external distraction device: A 1-year cephalometric follow-up. J Craniofac Surg 10: 312, 1999 5. Krimmel M, Cornelius CP, Roser M, et al: External distraction of the maxilla in patients with craniofacial dysplasia. J Craniofac Surg 12:458, 2001 6. Wen-Ching Ko E, Figueroa AA, Polley JW: Soft tissue profile changes after maxillary advancement with distraction osteogenesis by use of a rigid external distraction device: A 1-year follow-up. J Oral Maxillofac Surg 58:959, 2000 7. Wiltfang J, Hirschfelder U, Neukam FW, et al: Long-term results of distraction osteogenesis of the maxilla and midface. Br J Oral Maxillofac Surg 40:473, 2002 8. Emparanza A, Zwetyenga N, Siberchicot F, et al: La distraction osseuse dans les hypoplasies du maxillaire. A propos de 14 cas cliniques. Ann Chir Plast Esthet 46:285, 2001 9. Karakasis D, Hadjipetrou L: Advancement of the anterior maxilla by distraction (case report). J Craniomaxillofac Surg 32:150, 2004 10. Kessler P, Wiltfang J, Schultze-Mosgau S, et al: Distraction osteogenesis of the maxilla and midface using a subcutaneous device: Report of four cases. Br J Oral Maxillofac Surg 39:13, 2001
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