Ideas and Innovations Combined Orthognathic Distraction Procedure: Le Fort I Maxillary Osteotomy and Mandibular Curvilinear Distraction Osteogenesis. A New Technique for Craniofacial Management Stephen A. Schendel, M.D., D.D.S. Hagai Hazan-Molina, D.M.D., M.Sc. Dror Aizenbud, D.M.D., M.Sc. Stanford and Los Angeles, Calif.; and Haifa, Israel
Summary: Dentofacial deformities are traditionally treated by maxillary and mandibular osteotomies conducted separately or simultaneously. Recently, distraction osteogenesis has become an irreplaceable part of the surgical armamentarium, for its ability to induce new bone formation between the surfaces of bone segments that are gradually separated by incremental traction, along with a simultaneous expansion of the surrounding soft-tissue envelope. The aim of this article is to describe a combined surgical technique consisting of simultaneous maxillary Le Fort I advancement and mandibular surgical repositioning by means of bilateral sagittal split osteotomy with a curvilinear distractor based on a preliminary computerized presurgical prediction.(Plast. Reconstr. Surg. 133: 874, 2014.)
R
ecently, distraction osteogenesis has become one of the surgical strategies for dentofacial deformity management.1 The craniofacial reconstruction results that have been achieved are considered stable because of the ability of the s oft-tissue envelope (i.e., skin, muscles, fascia, nerves, and vessels) to regenerate under tension during the distraction process. Thus, distraction osteogenesis of the craniofacial skeleton has the benefit of simultaneously increasing bone length and volume of the surrounding soft tissues.2 Nonetheless, it is considered less accurate than orthoghree-dimensional nathic surgery.3 The ideal t curvilinear mandibular distraction may fit an ideal maxillary position and result in the best possible anatomical correction of congenital craniofacial deformities with normal functioning.2 Our aim is to describe a combined surgical technique consisting of simultaneous maxillary Le Fort I advancement and mandibular surgical repositioning by From the Department of Surgery, Stanford University; Department of Orthodontics, University of California–Los Angeles School of Dentistry; and Orthodontic and Craniofacial Anomalies Department, School of Graduate Dentistry, Rambam Health Care Campus and Technion Faculty of Medicine. Received for publication August 14, 2013; accepted October 18, 2013. Copyright © 2014 by the American Society of Plastic Surgeons DOI: 10.1097/PRS.0000000000000055
874
means of bilateral sagittal split osteotomy with a curvilinear distractor based on a preliminary computerized presurgical prediction. Preoperative lateral cephalographs of the patient were processed by direct digitization. The maxilla was first repositioned in the surgical prediction program. Next, the digital templates, corresponding to the actual distractor and spiral growth curve, were generated and superimposed onto the lateral cephalometric tracing created by the program for the surgical forecast (Fig. 1). The digital distractor template was then “activated” along the spiral growth curve template until the ideal position of the mandible was reached (Fig. 2). Based on this method, the actual distractor type and size, the amount of distraction, and accurate position on the mandible can be accurately determined and applied during surgery. The actual procedure begins with presurgical orthodontic preparation. This preliminary orthodontic stage, by means of a fixed orthodontic appliance, is aimed to level and align both maxillary and mandibular dental arches and to contribute to arch accommodation, resulting in the best-fit postsurgical occlusion.
Disclosure: None of the authors has a financial interest in any of the products or devices mentioned in this article.
www.PRSJournal.com
Volume 133, Number 4 • Combined Distraction Procedure
Fig. 1. Presurgical prediction included the digital templates, corresponding to the actual distractor and spiral growth curve, produced by the software program for the surgical forecast, superimposed onto the preliminary lateral cephalometric radiograph and tracing.
The first step of the surgical procedure includes maxillary repositioning through a Le Fort I horizontal osteotomy performed at the level of the nasal floor with pterygomaxillary disjunction, nasal septum separation from the palate, and nasal wall separation. Maxillary separation from the skull is performed through down-fracturing and the preservation of adequate blood supply to
the individual osteotomized segments. A surgical splint is used to facilitate accurate maxillary repositioning in the desired relationship with the skull and mandible according to the computerized preplanning before maxillary rigid fixation with miniplates. The mandible is then osteotomized by means of the Obwegeser-Dal Pont sagittal split ramus osteotomy technique with the modification described by Hunsuck,4 as it provides an increased bone interface. The intraoral incision is made from the mid ramus lateral to the first molar along the external oblique line. The desired osteotomy line is determined through the computerized prediction program based on lateral cephalometric tracings combined with the patient’s photographs (Fig. 2).5 The adequate curved distractor is then fixed to the proximal segment. This allows the distractor to be expanded freely until it can be fixed to the distal component. Once both sides are placed, the intermaxillary fixation is released and the distractors collapse until the medial and lateral sagittal split segments are still overlapping. The activating rod is then inserted and turned until it engages the sliding component of the distractor. After a latency period of 3 days, the distraction osteogenesis starts at a rate of 1 mm/ day. After the distraction is complete, the external activating pin is removed under local anesthesia. The distractor can be left in if the patient has completed growth or can be removed at approximately the sixth postoperative month (Fig. 3).
Fig. 2. Presurgical prediction of a patient suffering from a craniofacial deformity treated by the combined Le Fort I advancement and mandibular surgical repositioning by means of bilateral sagittal split osteotomy and distraction osteogenesis using a curvilinear distractor. (Left) Preliminary profile. (Center) After maxillary and mandibular surgical repositioning. (Right) With superimposition of the preliminary lateral cephalometric tracing.
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Plastic and Reconstructive Surgery • April 2014
Fig. 3. The same patient shown in Figure 2. (Above, left) Preoperative facial profile. (Above, right) Postsurgical facial profile. (Below, left) Preoperative lateral cephalometric radiograph. (Below, right) Postsurgical lateral cephalometric radiograph.
Although distraction osteogenesis is considered less accurate than orthognathic surgery,3 the advantage offered by this combined orthognathic distraction technique is the possibility of simultaneously combining the reconstruction of horizontal and vertical jaw vectors based on preplanned computerized prediction.5 Thus, maxillary Le Fort I repositioning and fixation as a template for the desired position of the mandible enable the surgeon to refine the reliability of the distraction and the accuracy of the resulting final jaw position and occlusion. Preoperative surgical planning and the possibility of evaluating the surgical outcome can provide a better predictable surgical result and save time and expenses. It may reduce surgical risks and morbidity and result in fewer surgical revisions. Furthermore, the use of internal multidirectional curvilinear distractors with bilateral
876
sagittal split osteotomy allows mandibular movement along the logarithmic spiral path of natural mandibular growth, with less relapse in the future caused by physiologic movement.1,6,7 To conclude, our findings demonstrate that a maxillary and mandibular surgical advancement protocol combining maxillary Le Fort I and mandibular bilateral sagittal split osteotomy with curvilinear distraction osteogenesis is beneficial for management of craniofacial deformity. Dror Aizenbud, D.M.D., M.Sc. Orthodontic and Craniofacial Department School of Graduate Dentistry Rambam Health Care Campus P.O. Box 9602 Haifa 31096, Israel [email protected]
Volume 133, Number 4 • Combined Distraction Procedure PATIENT CONSENT
Patient provided written consent for the use of patient’s image. REFERENCES 1. Aizenbud D, Hazan-Molina H, Thimmappa B, Hopkins EM,Schendel SA. Curvilinear mandibular distraction results and long-term stability effects in a group of 40 patients. Plast Reconstr Surg. 2010;125:1771–1780. 2. Hazan-Molina H, Molina-Hazan V, Schendel SA, Aizenbud D. Reliability of panoramic radiographs for the assessment of mandibular elongation after distraction osteogenesis procedures. Orthod Craniofac Res. 2011;14:25–32.
3. Van Sickels JE. Distraction osteogenesis versus orthognathic surgery. Am J Orthod Dentofacial Orthop. 2000;118: 482–484. 4. Hunsuck EE. A modified intraoral sagittal splitting technic for correction of mandibular prognathism. J Oral Surg. 1968;26:250–253. 5. Schendel S, Hazan-Molina H, Rachmiel A, Aizenbud D. The future in craniofacial surgery: Computer-assisted planning. Rambam Maimonides Med J. 2012;3:e0012. 6. Moss M, Moss-Salentjin L, Ostreicher H. The logarithmic properties of active and passive mandibular growth. Am J Orthod. 1974;66:645–664. 7. Ricketts RM. The biologic significance of the divine proportion and Fibonacci series. Am J Orthod. 1982;81:351–370.
877
Summary: Dentofacial deformities are traditionally treated by maxillary and mandibular osteotomies conducted separately or simultaneously. Recently, distraction osteogenesis has become an irreplaceable part of the surgical armamentarium, for its ability to induce new bone formation between the surfaces of bone segments that are gradually separated by incremental traction, along with a simultaneous expansion of the surrounding soft-tissue envelope. The aim of this article is to describe a combined surgical technique consisting of simultaneous maxillary Le Fort I advancement and mandibular surgical repositioning by means of bilateral sagittal split osteotomy with a curvilinear distractor based on a preliminary computerized presurgical prediction.(Plast. Reconstr. Surg. 133: 874, 2014.)
R
ecently, distraction osteogenesis has become one of the surgical strategies for dentofacial deformity management.1 The craniofacial reconstruction results that have been achieved are considered stable because of the ability of the s oft-tissue envelope (i.e., skin, muscles, fascia, nerves, and vessels) to regenerate under tension during the distraction process. Thus, distraction osteogenesis of the craniofacial skeleton has the benefit of simultaneously increasing bone length and volume of the surrounding soft tissues.2 Nonetheless, it is considered less accurate than orthoghree-dimensional nathic surgery.3 The ideal t curvilinear mandibular distraction may fit an ideal maxillary position and result in the best possible anatomical correction of congenital craniofacial deformities with normal functioning.2 Our aim is to describe a combined surgical technique consisting of simultaneous maxillary Le Fort I advancement and mandibular surgical repositioning by From the Department of Surgery, Stanford University; Department of Orthodontics, University of California–Los Angeles School of Dentistry; and Orthodontic and Craniofacial Anomalies Department, School of Graduate Dentistry, Rambam Health Care Campus and Technion Faculty of Medicine. Received for publication August 14, 2013; accepted October 18, 2013. Copyright © 2014 by the American Society of Plastic Surgeons DOI: 10.1097/PRS.0000000000000055
874
means of bilateral sagittal split osteotomy with a curvilinear distractor based on a preliminary computerized presurgical prediction. Preoperative lateral cephalographs of the patient were processed by direct digitization. The maxilla was first repositioned in the surgical prediction program. Next, the digital templates, corresponding to the actual distractor and spiral growth curve, were generated and superimposed onto the lateral cephalometric tracing created by the program for the surgical forecast (Fig. 1). The digital distractor template was then “activated” along the spiral growth curve template until the ideal position of the mandible was reached (Fig. 2). Based on this method, the actual distractor type and size, the amount of distraction, and accurate position on the mandible can be accurately determined and applied during surgery. The actual procedure begins with presurgical orthodontic preparation. This preliminary orthodontic stage, by means of a fixed orthodontic appliance, is aimed to level and align both maxillary and mandibular dental arches and to contribute to arch accommodation, resulting in the best-fit postsurgical occlusion.
Disclosure: None of the authors has a financial interest in any of the products or devices mentioned in this article.
www.PRSJournal.com
Volume 133, Number 4 • Combined Distraction Procedure
Fig. 1. Presurgical prediction included the digital templates, corresponding to the actual distractor and spiral growth curve, produced by the software program for the surgical forecast, superimposed onto the preliminary lateral cephalometric radiograph and tracing.
The first step of the surgical procedure includes maxillary repositioning through a Le Fort I horizontal osteotomy performed at the level of the nasal floor with pterygomaxillary disjunction, nasal septum separation from the palate, and nasal wall separation. Maxillary separation from the skull is performed through down-fracturing and the preservation of adequate blood supply to
the individual osteotomized segments. A surgical splint is used to facilitate accurate maxillary repositioning in the desired relationship with the skull and mandible according to the computerized preplanning before maxillary rigid fixation with miniplates. The mandible is then osteotomized by means of the Obwegeser-Dal Pont sagittal split ramus osteotomy technique with the modification described by Hunsuck,4 as it provides an increased bone interface. The intraoral incision is made from the mid ramus lateral to the first molar along the external oblique line. The desired osteotomy line is determined through the computerized prediction program based on lateral cephalometric tracings combined with the patient’s photographs (Fig. 2).5 The adequate curved distractor is then fixed to the proximal segment. This allows the distractor to be expanded freely until it can be fixed to the distal component. Once both sides are placed, the intermaxillary fixation is released and the distractors collapse until the medial and lateral sagittal split segments are still overlapping. The activating rod is then inserted and turned until it engages the sliding component of the distractor. After a latency period of 3 days, the distraction osteogenesis starts at a rate of 1 mm/ day. After the distraction is complete, the external activating pin is removed under local anesthesia. The distractor can be left in if the patient has completed growth or can be removed at approximately the sixth postoperative month (Fig. 3).
Fig. 2. Presurgical prediction of a patient suffering from a craniofacial deformity treated by the combined Le Fort I advancement and mandibular surgical repositioning by means of bilateral sagittal split osteotomy and distraction osteogenesis using a curvilinear distractor. (Left) Preliminary profile. (Center) After maxillary and mandibular surgical repositioning. (Right) With superimposition of the preliminary lateral cephalometric tracing.
875
Plastic and Reconstructive Surgery • April 2014
Fig. 3. The same patient shown in Figure 2. (Above, left) Preoperative facial profile. (Above, right) Postsurgical facial profile. (Below, left) Preoperative lateral cephalometric radiograph. (Below, right) Postsurgical lateral cephalometric radiograph.
Although distraction osteogenesis is considered less accurate than orthognathic surgery,3 the advantage offered by this combined orthognathic distraction technique is the possibility of simultaneously combining the reconstruction of horizontal and vertical jaw vectors based on preplanned computerized prediction.5 Thus, maxillary Le Fort I repositioning and fixation as a template for the desired position of the mandible enable the surgeon to refine the reliability of the distraction and the accuracy of the resulting final jaw position and occlusion. Preoperative surgical planning and the possibility of evaluating the surgical outcome can provide a better predictable surgical result and save time and expenses. It may reduce surgical risks and morbidity and result in fewer surgical revisions. Furthermore, the use of internal multidirectional curvilinear distractors with bilateral
876
sagittal split osteotomy allows mandibular movement along the logarithmic spiral path of natural mandibular growth, with less relapse in the future caused by physiologic movement.1,6,7 To conclude, our findings demonstrate that a maxillary and mandibular surgical advancement protocol combining maxillary Le Fort I and mandibular bilateral sagittal split osteotomy with curvilinear distraction osteogenesis is beneficial for management of craniofacial deformity. Dror Aizenbud, D.M.D., M.Sc. Orthodontic and Craniofacial Department School of Graduate Dentistry Rambam Health Care Campus P.O. Box 9602 Haifa 31096, Israel [email protected]
Volume 133, Number 4 • Combined Distraction Procedure PATIENT CONSENT
Patient provided written consent for the use of patient’s image. REFERENCES 1. Aizenbud D, Hazan-Molina H, Thimmappa B, Hopkins EM,Schendel SA. Curvilinear mandibular distraction results and long-term stability effects in a group of 40 patients. Plast Reconstr Surg. 2010;125:1771–1780. 2. Hazan-Molina H, Molina-Hazan V, Schendel SA, Aizenbud D. Reliability of panoramic radiographs for the assessment of mandibular elongation after distraction osteogenesis procedures. Orthod Craniofac Res. 2011;14:25–32.
3. Van Sickels JE. Distraction osteogenesis versus orthognathic surgery. Am J Orthod Dentofacial Orthop. 2000;118: 482–484. 4. Hunsuck EE. A modified intraoral sagittal splitting technic for correction of mandibular prognathism. J Oral Surg. 1968;26:250–253. 5. Schendel S, Hazan-Molina H, Rachmiel A, Aizenbud D. The future in craniofacial surgery: Computer-assisted planning. Rambam Maimonides Med J. 2012;3:e0012. 6. Moss M, Moss-Salentjin L, Ostreicher H. The logarithmic properties of active and passive mandibular growth. Am J Orthod. 1974;66:645–664. 7. Ricketts RM. The biologic significance of the divine proportion and Fibonacci series. Am J Orthod. 1982;81:351–370.
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