- Email: [email protected]
Distraction osteogenesis versus orthognathic surgery
COMMENTARY Distraction osteogenesis versus orthognathic surgery With each new issue of the Journal in the coming year, you will see the increased use of commentaries to introduce and emphasize particular subjects. One to three original research articles will follow each commentary or brief review. This month the topic of interest is distraction osteogenesis, and the commentary is written by Professor Joseph Van Sickels, oral and maxillofacial surgeon, Lexington, Kentucky. Take time to review his thoughts on this relatively new technique, then examine the accompanying article by Del Santo et al and its related clinical findings.
istraction osteogenesis is a relatively new technique that has gained popularity as a treatment for skeletal discrepancies in the maxillofacial complex.1-15 The technology was first used to treat long bone discrepancies and is now being used for the management of craniofacial and dentofacial deformities.16,17 While some individuals suggest that distraction osteogenesis may replace routine orthognathic procedures, it should instead be viewed as an alternative technique that can be used to correct maxillary and mandibular discrepancies. It has been used to lengthen both maxillary and mandibular arches in patients who have traditionally been difficult to treat with orthognathic surgery.1,2,6,18,19 For other patients, it represents an entirely new option for the creation of intra-arch space.9-11 At most North American centers, distraction has been used primarily to treat severe anteroposterior discrepancies of the maxilla and mandible.1,18,19 In some northern European centers, however, it has been used to treat patients with routine Class II deepbite malocclusions.20 Like any new procedure, as it gains acceptance, distraction osteogenesis will change the way problems are diagnosed and addressed. When one is dealing with intra-arch discrepancies, distraction osteogenesis presents an alternative to extractions and the stripping of teeth to gain space in the upper and lower arches. Understanding that expansion of the lower arch is a viable option changes the algorithm of treatment. When there is excessive tooth mass, extraction or the stripping of teeth is the correct treatment. However, when a transverse discrepancy exists, space can be gained through distraction. Preliminary studies have suggested that the results of mandibular expansion through distraction are stable.9-11 When intra-arch distraction is used to lengthen the maxilla or mandible, orthodontic alignment of arches is not necessary before the procedure because space will be created with the surgery.14
D
Reprint requests to: Joseph E. Van Sickels, D-512 Chandler Medical Center, College of Dentistry, Lexington, KY 40536-0297; e-mail, [email protected]. Am J Orthod Dentofacial Orthop 2000;118:482-4 Copyright © 2000 by the American Association of Orthodontists. 0889-5406/2000/$12.00 + 0 8/1/110517 doi.10.1067/mod.2000.110517
482
DIFFERENCES BETWEEN DISTRACTION OSTEOGENESIS AND ORTHOGNATHIC SURGERY
Orthognathic surgery is well known among orthodontists and oral and maxillofacial surgeons. After a patient has been orthodontically prepared, movement of the maxilla and mandible can be completed within a matter of a few hours. Postoperative orthopedic manipulation of the occlusion is limited. Segmental discrepancies of the maxilla can be addressed by separating the maxilla into predetermined pieces at the time of surgery. The maxilla may be moved in multiple directions in space. Stability varies markedly with the amount and direction of maxillary movement, with forward and inferior movements being the least stable.21 Likewise, the mandible can be moved in several dimensions in space. Lengthening of the ramus is extremely unstable, while advancement of the mandible for routine movements is extremely stable. Large advancements have shown increasing amounts of instability.22 Narrowing of the mandible can be accomplished with simultaneous advancement and retraction of the mandible. Moving both jaws simultaneously can be accomplished with careful planning. The orthodontic preparation for distraction varies according to which jaw will be moved and whether the maxilla or mandible will be moved as one piece or with intra-arch distraction. Intra-arch distraction may be used as first-phase therapy before addressing whole-arch discrepancies. The time in the operating room for distraction osteogenesis is relatively brief when compared with some orthognathic procedures. However, follow-up is more extensive. Vector control is one of the more challenging aspects of distraction. The primary vector of distraction is largely dictated by the placement of the distractor. A number of factors modify the primary vector including the rigidity of the appliance, soft tissue influences, and muscular attachments. For maxillary movement, advancement with simultaneous widening of the transverse dimension is possible by incorporating an expansion appliance in the palate. Reports on patients with cleft palate have suggested that maxillary advancements achieved by distraction are more stable than the advancements achieved with orthognathic surgery and have a minimal influence on velopharyngeal compe-
Van Sickels 483
American Journal of Orthodontics and Dentofacial Orthopedics Volume 118, Number 5
tence.18,19 Most maxillary advancement in patients with cleft palate requires an inferior movement. Anterior-inferior movement of the maxilla is possible through orientation of the distractor, with or without additional elastic mechanics. Large mandibular advancements with simultaneous symphyseal widening are possible but require 3 separate distractors. Simultaneous movement of the maxilla and mandible is also possible but is complex and technically demanding. Asymmetries present varying degrees of difficulty to correct with distraction and frequently necessitate early orthodontic intervention. Perhaps the greatest difference between distraction osteogenesis and orthognathic surgery is the role that the patient plays in his or her own treatment. The patient undergoing distraction osteogenesis must understand and be willing to activate an appliance 2 or more times per day for a period of 1 week or more. Frequent office visits are necessary to ensure compliance and adjustment of appliances during therapy. On several occasion I have had patients turn their appliances the wrong direction, despite presurgical and postsurgical teaching sessions. While some clinicians prefer molding the regenerate after the period of distraction, others (including me) prefer to use elastics to modify the vector during the period of distraction to minimize the occlusal discrepancies seen at the end of a distraction period.2,7 The occlusion at the end of distraction is much less precise than that seen with orthognathic surgery. Finishing adjustments of the occlusion should be achieved while the regenerate is still moldable. Patients who are noncompliant with follow-up visits are poor candidates for distraction. Distractors may be tooth-borne or bone-borne. Most tooth-borne appliances can be fabricated in orthodontic laboratories. In contrast, bone-borne appliances are purchased through several different instrument companies. The cost difference is considerable. Vector control can be difficult with either appliance. Tooth-borne appliances may not be possible in the mixed dentition period or when periodontal disease compromises the dentition. An interesting possible advantage to distraction is its effect on the inferior alveolar nerve. A recent study suggested that if acute nerve injury is avoided with surgery, then up to 10 mm of distraction of the mandible would appear to produce minimal effects on inferior alveolar nerve function.15 Tooth movement into the regenerate bone has been investigated.3,5 It appears that the best time to initiate tooth movement is immediately after the end of distraction. SUMMARY AND CONCLUSIONS
Distraction osteogenesis presents an alternative to orthognathic surgery that appears to have some advan-
tages for large advancements in the maxilla and the mandible. However, it does not have the versatility offered by orthognathic procedures and requires more office time and a cooperative patient. Additionally, the occlusion following a period of distraction is much less precise than what is seen with conventional orthognathic surgery. Correction of segmental discrepancies in the maxilla is limited with distraction. Currently it does not appear to offer any distinct advantages over orthognathic surgery for more modest movements of the mandible and the maxilla. Intra-arch distraction has caused a paradigm shift in the treatment of patients by allowing stable expansion of transverse discrepancies of the mandible and segmental anterior-posterior discrepancies of the maxilla and mandible. Intra-arch distraction may be used as a first-phase procedure or as definitive therapy. When intra-arch distraction is used to correct whole-arch discrepancies, crowding is resolved as the arch length discrepancy is corrected. Design of distractors, control of the direction of distraction, intraoral versus extraoral appliances, and tooth-borne versus bone-borne appliances are some of the many areas of research and clinical development that will be defined in the next few years. Joseph E. Van Sickels, DDS, Professor and Director of Residency Education, Oral and Maxillofacial Surgery Chandler Medical Center, College of Dentistry, Lexington, Ky REFERENCES 1. Molina F. Combined maxillary and mandibular distraction osteogenesis. Semin Orthod 1999;5:41-5. 2. Hanson PR, Melugin MB. Orthodontic management of the patient undergoing mandibular distraction osteogeneis. Semin Orthod 1999;5:25-34. 3. Liou EJ, Figueroa AA, Polley JW. Rapid orthodontic tooth movement into newly distracted bone after mandibular distraction osteogenesis in a canine model. Am J Orthod Dentofacial Orthop 2000;117:391-8. 4. Cope JB, Yamashita J, Healy S, Dechow PC, Harper RP. Force level and strain patterns during bilateral mandibular osteodistraction. J Oral Maxillofac Surg 2000;58:171-8. 5. Cope JB, Harper RP, Samchukov ML. Experimental tooth movement through regenerate alveolar bone: a pilot study. Am J Orthod Dentofacial Orthop 1999;116:501-5. 6. Karp NS, Thorne CH, McCarth JG, Sissons HA. Bone lengthening in the craniofacial skeleton. Ann Plast Surg 1990;24:231-7. 7. Grayson BH, Santiago PE. Treatment planning and biomechanics of distraction osteogenesis from an orthodontic perspective. Semin Orthod 1999;5:9-24. 8. Altuna G, Walker DA, Freeman E. Rapid orthopedic lengthening of the mandible in primates by sagittal split osteotomy and distraction osteogenesis: a pilot study. Int J Adult Orthod Orthognath Surg 1995;10:59-64. 9. Kewitt GF, Van Sickels. Long-term effect of mandibular midline distraction osteogenesis on the status of the temporomandibular
484 Van Sickels
10.
11.
12.
13.
14.
15.
American Journal of Orthodontics and Dentofacial Orthopedics November 2000
joint, teeth, periodontal structures, and neurosensory function. J Oral Maxillofac Surg 1999;57:1419-25. Weil TS, Van Sickels JE, Payne CJ. Distraction osteogenesis for correction of transverse mandibular deficiency: a preliminary report. J Oral Maxillofac Surg 1997;55:953-60. Guerrero CA, Bell WH, Contasti GI, Rodriguez AM. Mandibular widening by intraoral distraction osteogenesis. Br J Oral Maxillofac Surg 1997;35:383-92. Harper RP, Bell WH, Hinton RJ, Browne R, Cherkashin AM, Samchuckov ML. Reactive changes in the temporomandibular joint after mandibular midline osteodistraction. Br J Oral Maxillofac Surg 1997;35:20-5. Niederhagen B, Braumann B, Schmolke C, Appel T, von Lindern JJ, Berge S. Tooth-borne distraction of the mandible: an experimental study. Int J Oral Maxillofac Surg 1999;28:475-9. Dessner S, Razdolsky Y, El-Bialy T, Evans CA. Mandibular lengthening using preprogrammed intraoral tooth-borne distraction devices. J Oral Maxillofac Surg 1999;57:1318-22. Makarov MR, Harper RP, Cope JB, Samchukov ML. Evaluation of inferior alveolar nerve function during distraction osteogenesis in the dog. J Oral Maxillofac Surg 1998;56:1417-23.
16. Ilizarov GA. The principles of the Ilizarov method.1988. Bull Hosp Jt Dis 1997;56:49-53. 17. Aronson J. Experimental and clinical experiences with distraction osteogenesis. Cleft Palate Craniofac J 1994;31;473-81. 18. Ko EW, Figueroa AA, Guyette TW, Polley JW, Law WR. 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 1999;312-20. 19. Figueroa AA, Polley JW. Management of severe cleft maxillary deficiency with distraction osteogenesis: procedure and results. Am J Orthod Dentofacial Orthop 1999;115:1-12. 20. Mommaerts MY, Jacobs W, de Jonghe N. Mandibular distraction using a dynamic osteosynthesis system: MD-DOS. Concepts and surgical technic. Rev Stomatol Chir Maxillofac 1998;99:223-30. 21. Proffit WR, Turvey TA, Phillips C. Orthognathic surgery: a hierarchy of stability. Int J Adult Orthod Orhognath Surg 1996;11:191-204. 22. Van Sickels JE, Dolce C, Keeling S, Tiner BD, Clark GM, Rugh JD. Technical factors accounting for stability of a bilateral sagittal split osteotomy advancement: wire osteosynthesis versus rigid fixation. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2000;89:19-23.
AAO MEETING CALENDAR 2001 2002 2003 2004 2005 2006
— Toronto, Ontario, Canada, May 5 to 9, Toronto Convention Center — Philadelphia, Pa, May 4 to 8, Pennsylvania Convention Center — Hawaiian Islands, May 2 to 9, Hawaii Convention Center — Orlando, Fla, May 1 to 5, Orange County Convention Center — San Francisco, Calif, May 21 to 26, Moscone Convention Center — New Orleans, La, April 29 to May 3, Ernest N. Morial Convention Center
istraction osteogenesis is a relatively new technique that has gained popularity as a treatment for skeletal discrepancies in the maxillofacial complex.1-15 The technology was first used to treat long bone discrepancies and is now being used for the management of craniofacial and dentofacial deformities.16,17 While some individuals suggest that distraction osteogenesis may replace routine orthognathic procedures, it should instead be viewed as an alternative technique that can be used to correct maxillary and mandibular discrepancies. It has been used to lengthen both maxillary and mandibular arches in patients who have traditionally been difficult to treat with orthognathic surgery.1,2,6,18,19 For other patients, it represents an entirely new option for the creation of intra-arch space.9-11 At most North American centers, distraction has been used primarily to treat severe anteroposterior discrepancies of the maxilla and mandible.1,18,19 In some northern European centers, however, it has been used to treat patients with routine Class II deepbite malocclusions.20 Like any new procedure, as it gains acceptance, distraction osteogenesis will change the way problems are diagnosed and addressed. When one is dealing with intra-arch discrepancies, distraction osteogenesis presents an alternative to extractions and the stripping of teeth to gain space in the upper and lower arches. Understanding that expansion of the lower arch is a viable option changes the algorithm of treatment. When there is excessive tooth mass, extraction or the stripping of teeth is the correct treatment. However, when a transverse discrepancy exists, space can be gained through distraction. Preliminary studies have suggested that the results of mandibular expansion through distraction are stable.9-11 When intra-arch distraction is used to lengthen the maxilla or mandible, orthodontic alignment of arches is not necessary before the procedure because space will be created with the surgery.14
D
Reprint requests to: Joseph E. Van Sickels, D-512 Chandler Medical Center, College of Dentistry, Lexington, KY 40536-0297; e-mail, [email protected]. Am J Orthod Dentofacial Orthop 2000;118:482-4 Copyright © 2000 by the American Association of Orthodontists. 0889-5406/2000/$12.00 + 0 8/1/110517 doi.10.1067/mod.2000.110517
482
DIFFERENCES BETWEEN DISTRACTION OSTEOGENESIS AND ORTHOGNATHIC SURGERY
Orthognathic surgery is well known among orthodontists and oral and maxillofacial surgeons. After a patient has been orthodontically prepared, movement of the maxilla and mandible can be completed within a matter of a few hours. Postoperative orthopedic manipulation of the occlusion is limited. Segmental discrepancies of the maxilla can be addressed by separating the maxilla into predetermined pieces at the time of surgery. The maxilla may be moved in multiple directions in space. Stability varies markedly with the amount and direction of maxillary movement, with forward and inferior movements being the least stable.21 Likewise, the mandible can be moved in several dimensions in space. Lengthening of the ramus is extremely unstable, while advancement of the mandible for routine movements is extremely stable. Large advancements have shown increasing amounts of instability.22 Narrowing of the mandible can be accomplished with simultaneous advancement and retraction of the mandible. Moving both jaws simultaneously can be accomplished with careful planning. The orthodontic preparation for distraction varies according to which jaw will be moved and whether the maxilla or mandible will be moved as one piece or with intra-arch distraction. Intra-arch distraction may be used as first-phase therapy before addressing whole-arch discrepancies. The time in the operating room for distraction osteogenesis is relatively brief when compared with some orthognathic procedures. However, follow-up is more extensive. Vector control is one of the more challenging aspects of distraction. The primary vector of distraction is largely dictated by the placement of the distractor. A number of factors modify the primary vector including the rigidity of the appliance, soft tissue influences, and muscular attachments. For maxillary movement, advancement with simultaneous widening of the transverse dimension is possible by incorporating an expansion appliance in the palate. Reports on patients with cleft palate have suggested that maxillary advancements achieved by distraction are more stable than the advancements achieved with orthognathic surgery and have a minimal influence on velopharyngeal compe-
Van Sickels 483
American Journal of Orthodontics and Dentofacial Orthopedics Volume 118, Number 5
tence.18,19 Most maxillary advancement in patients with cleft palate requires an inferior movement. Anterior-inferior movement of the maxilla is possible through orientation of the distractor, with or without additional elastic mechanics. Large mandibular advancements with simultaneous symphyseal widening are possible but require 3 separate distractors. Simultaneous movement of the maxilla and mandible is also possible but is complex and technically demanding. Asymmetries present varying degrees of difficulty to correct with distraction and frequently necessitate early orthodontic intervention. Perhaps the greatest difference between distraction osteogenesis and orthognathic surgery is the role that the patient plays in his or her own treatment. The patient undergoing distraction osteogenesis must understand and be willing to activate an appliance 2 or more times per day for a period of 1 week or more. Frequent office visits are necessary to ensure compliance and adjustment of appliances during therapy. On several occasion I have had patients turn their appliances the wrong direction, despite presurgical and postsurgical teaching sessions. While some clinicians prefer molding the regenerate after the period of distraction, others (including me) prefer to use elastics to modify the vector during the period of distraction to minimize the occlusal discrepancies seen at the end of a distraction period.2,7 The occlusion at the end of distraction is much less precise than that seen with orthognathic surgery. Finishing adjustments of the occlusion should be achieved while the regenerate is still moldable. Patients who are noncompliant with follow-up visits are poor candidates for distraction. Distractors may be tooth-borne or bone-borne. Most tooth-borne appliances can be fabricated in orthodontic laboratories. In contrast, bone-borne appliances are purchased through several different instrument companies. The cost difference is considerable. Vector control can be difficult with either appliance. Tooth-borne appliances may not be possible in the mixed dentition period or when periodontal disease compromises the dentition. An interesting possible advantage to distraction is its effect on the inferior alveolar nerve. A recent study suggested that if acute nerve injury is avoided with surgery, then up to 10 mm of distraction of the mandible would appear to produce minimal effects on inferior alveolar nerve function.15 Tooth movement into the regenerate bone has been investigated.3,5 It appears that the best time to initiate tooth movement is immediately after the end of distraction. SUMMARY AND CONCLUSIONS
Distraction osteogenesis presents an alternative to orthognathic surgery that appears to have some advan-
tages for large advancements in the maxilla and the mandible. However, it does not have the versatility offered by orthognathic procedures and requires more office time and a cooperative patient. Additionally, the occlusion following a period of distraction is much less precise than what is seen with conventional orthognathic surgery. Correction of segmental discrepancies in the maxilla is limited with distraction. Currently it does not appear to offer any distinct advantages over orthognathic surgery for more modest movements of the mandible and the maxilla. Intra-arch distraction has caused a paradigm shift in the treatment of patients by allowing stable expansion of transverse discrepancies of the mandible and segmental anterior-posterior discrepancies of the maxilla and mandible. Intra-arch distraction may be used as a first-phase procedure or as definitive therapy. When intra-arch distraction is used to correct whole-arch discrepancies, crowding is resolved as the arch length discrepancy is corrected. Design of distractors, control of the direction of distraction, intraoral versus extraoral appliances, and tooth-borne versus bone-borne appliances are some of the many areas of research and clinical development that will be defined in the next few years. Joseph E. Van Sickels, DDS, Professor and Director of Residency Education, Oral and Maxillofacial Surgery Chandler Medical Center, College of Dentistry, Lexington, Ky REFERENCES 1. Molina F. Combined maxillary and mandibular distraction osteogenesis. Semin Orthod 1999;5:41-5. 2. Hanson PR, Melugin MB. Orthodontic management of the patient undergoing mandibular distraction osteogeneis. Semin Orthod 1999;5:25-34. 3. Liou EJ, Figueroa AA, Polley JW. Rapid orthodontic tooth movement into newly distracted bone after mandibular distraction osteogenesis in a canine model. Am J Orthod Dentofacial Orthop 2000;117:391-8. 4. Cope JB, Yamashita J, Healy S, Dechow PC, Harper RP. Force level and strain patterns during bilateral mandibular osteodistraction. J Oral Maxillofac Surg 2000;58:171-8. 5. Cope JB, Harper RP, Samchukov ML. Experimental tooth movement through regenerate alveolar bone: a pilot study. Am J Orthod Dentofacial Orthop 1999;116:501-5. 6. Karp NS, Thorne CH, McCarth JG, Sissons HA. Bone lengthening in the craniofacial skeleton. Ann Plast Surg 1990;24:231-7. 7. Grayson BH, Santiago PE. Treatment planning and biomechanics of distraction osteogenesis from an orthodontic perspective. Semin Orthod 1999;5:9-24. 8. Altuna G, Walker DA, Freeman E. Rapid orthopedic lengthening of the mandible in primates by sagittal split osteotomy and distraction osteogenesis: a pilot study. Int J Adult Orthod Orthognath Surg 1995;10:59-64. 9. Kewitt GF, Van Sickels. Long-term effect of mandibular midline distraction osteogenesis on the status of the temporomandibular
484 Van Sickels
10.
11.
12.
13.
14.
15.
American Journal of Orthodontics and Dentofacial Orthopedics November 2000
joint, teeth, periodontal structures, and neurosensory function. J Oral Maxillofac Surg 1999;57:1419-25. Weil TS, Van Sickels JE, Payne CJ. Distraction osteogenesis for correction of transverse mandibular deficiency: a preliminary report. J Oral Maxillofac Surg 1997;55:953-60. Guerrero CA, Bell WH, Contasti GI, Rodriguez AM. Mandibular widening by intraoral distraction osteogenesis. Br J Oral Maxillofac Surg 1997;35:383-92. Harper RP, Bell WH, Hinton RJ, Browne R, Cherkashin AM, Samchuckov ML. Reactive changes in the temporomandibular joint after mandibular midline osteodistraction. Br J Oral Maxillofac Surg 1997;35:20-5. Niederhagen B, Braumann B, Schmolke C, Appel T, von Lindern JJ, Berge S. Tooth-borne distraction of the mandible: an experimental study. Int J Oral Maxillofac Surg 1999;28:475-9. Dessner S, Razdolsky Y, El-Bialy T, Evans CA. Mandibular lengthening using preprogrammed intraoral tooth-borne distraction devices. J Oral Maxillofac Surg 1999;57:1318-22. Makarov MR, Harper RP, Cope JB, Samchukov ML. Evaluation of inferior alveolar nerve function during distraction osteogenesis in the dog. J Oral Maxillofac Surg 1998;56:1417-23.
16. Ilizarov GA. The principles of the Ilizarov method.1988. Bull Hosp Jt Dis 1997;56:49-53. 17. Aronson J. Experimental and clinical experiences with distraction osteogenesis. Cleft Palate Craniofac J 1994;31;473-81. 18. Ko EW, Figueroa AA, Guyette TW, Polley JW, Law WR. 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 1999;312-20. 19. Figueroa AA, Polley JW. Management of severe cleft maxillary deficiency with distraction osteogenesis: procedure and results. Am J Orthod Dentofacial Orthop 1999;115:1-12. 20. Mommaerts MY, Jacobs W, de Jonghe N. Mandibular distraction using a dynamic osteosynthesis system: MD-DOS. Concepts and surgical technic. Rev Stomatol Chir Maxillofac 1998;99:223-30. 21. Proffit WR, Turvey TA, Phillips C. Orthognathic surgery: a hierarchy of stability. Int J Adult Orthod Orhognath Surg 1996;11:191-204. 22. Van Sickels JE, Dolce C, Keeling S, Tiner BD, Clark GM, Rugh JD. Technical factors accounting for stability of a bilateral sagittal split osteotomy advancement: wire osteosynthesis versus rigid fixation. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2000;89:19-23.
AAO MEETING CALENDAR 2001 2002 2003 2004 2005 2006
— Toronto, Ontario, Canada, May 5 to 9, Toronto Convention Center — Philadelphia, Pa, May 4 to 8, Pennsylvania Convention Center — Hawaiian Islands, May 2 to 9, Hawaii Convention Center — Orlando, Fla, May 1 to 5, Orange County Convention Center — San Francisco, Calif, May 21 to 26, Moscone Convention Center — New Orleans, La, April 29 to May 3, Ernest N. Morial Convention Center