Simultaneous Maxillary Distraction Osteogenesis Using a Twin-Track Distraction Device Combined with Alveolar Bone Grafting in Cleft Patients:Preliminary Report of a Technique
The simultaneous use of cleft reduction and maxillary advancement by distraction osteogenesis has not been applied routinely because of the difficulty in three-dimensional control and stabilization of the transported segments. This report describes a new approach of simultaneous bilateral alveolar cleft reduction and maxillary advancement by distraction osteogenesis combined with autogenous bone grafting. A custom-made Twin-Track device was used to allow bilateral alveolar cleft closure combined with simultaneous maxillary advancement, using distraction osteogenesis and a rigid external distraction system in a bilateral cleft lip and palate patient. After a maxillary Le Fort I osteotomy, autogenous iliac bone graft was placed in the cleft spaces before suturing. A latency period of six days was observed before activation. The rate of activation was one mm/d for the maxillary advancement and 0.5 mm/d for the segmental transport. Accordingly, the concave facial appearance was improved with acceptable occlusion, and complete bilateral cleft closure was attained. No adjustments were necessary to the vector of the transported segments during the activation and no complications were observed. The proposed Twin-Track device, based on the concept of track-guided bone transport, permitted three-dimensional control over the distraction processes allowing simultaneous cleft closure, maxillary distraction, and autogenous bone grafting. The combined simultaneous approach is extremely advantageous in correcting severe deformities, reducing the number of surgical interventions and, consequently, the total treatment time.Abstract
INTRODUCTION
Distraction osteogenesis has opened new perspectives for simultaneous management of severe craniofacial deformities. The main advantages of distraction compared with traditional methods of craniofacial reconstruction are the ability to generate new bone and a reduced morbidity rate.1–3
Refinements of techniques and emerging technologies, including combined simultaneous distraction osteogenesis of the maxilla and mandible, have greatly expanded the range of options for the management of cleft patients and have predictable and stable re-sults.4–7 The advantages of the combined simultaneous distraction osteogenesis include a reduction in the number of surgical interventions and minimal morbidity with consequent reduction of total treatment time and costs.5–7
However, distraction devices that allow for combined simultaneous bilateral cleft reduction and maxillary distraction are not currently available. This may be because of the complexity of the movements involved and the difficulty in three-dimensional control and stabilization of the transported segments.3 Consequently, techniques of simultaneous cleft reduction and maxillary advancement by distraction osteogenesis have not been applied routinely. Moreover, reducing the dentoalveolar defects by bone transport of a posterior segment does not eliminate completely the need for an additional bone graft in the residual nasal cleft space above the closed dentoalveolar cleft or docking site.8–11
Therefore, the authors developed a new method for simultaneous reduction of alveolar clefts and maxillary distraction osteogenesis combined with autogenous bone grafting. This new method has been applied successfully in our university hospital for all cases where simultaneous distraction of the maxillary arch is required. In this report, we present a case in which large bilateral clefts were closed by simultaneous transport osteogenesis of lateral segments, maxillary distraction, and autogenous bone grafting, using the innovated track-guided bone transport or Twin-Track distraction device (TT device).
MATERIALS AND METHODS
Case report
A 22-year-old man with a bilateral complete cleft lip and palate had been treated at medical centers in Japan and was not examined at the orthodontic clinic, Tokyo Medical and Dental University, until he was 20 years old. Clinical examination showed a severe maxillary retrusion, a Class III molar malocclusion, and an anterior and posterior crossbite. The overbite and overjet were −5 and three mm, respectively. He originally presented with a tiny oronasal fistula (0.5 by 0.5 mm) and bilateral clefts measuring five and 12 mm on the right and left sides, respectively. The lateral incisors and a right first premolar were congenitally missing, and the right canine presented with severe gingival recession on the mesial side (Figure 1A,B). Neither pharyngoplasty nor alveolar bone grafting had been performed. Cephalometric analysis demonstrated an underdeveloped maxilla.
Citation: The Angle Orthodontist 76, 1; 10.1043/0003-3219(2006)076[0164:SMDOUA]2.0.CO;2
Therefore, it was decided to transport the posterior segments to close the bilateral cleft spaces simultaneous with the advancement of the premaxilla using distraction osteogenesis. Combined autogenous iliac bone grafting was planned to fill the preexisting bilateral cleft space and the residual nasal cleft space above the docking site.
Before the simultaneous distraction osteogenesis, clinical orthodontic procedures included expansion of the maxillary lateral segments and the premaxilla and tooth alignment. Clinical photographs, dental casts, lateral and posteroanterior cephalograms, periapical and panoramic radiographs, and three-dimensional computed tomography (3D-CT) images were obtained preoperatively. Lateral cephalograms were also obtained after the latency period, after completion of the active period of distraction, and at the completion of the consolidation period. The amount of distraction osteogenesis, the progression of osteogenesis and remodeling, and any relapse were evaluated on the radiographs.
TT device
The TT device (patent pending) used in this study was invented by Dr Suzuki and Dr Buranastidporn. The distraction device consists of traction screws, traction microcables, bolts with attachments to the supporting teeth, and a horizontal double parallel labial arch, or Twin-Track arch, which was made from ordinary orthodontic wires.
The Twin-Track arch, working as rails, guides the movement of the transported dentoalveolar segment to the desired position. The Twin-Track arch is fitted and adjusted to the supporting teeth on the working model according to the predicted vector of the distracted dental arch resulting in an optimized maxillary archform and balanced occlusion. This system permits a predictable three-dimensional control of the transported segment without the need for adjustments of vectors or directions during distraction (Figure 2). The Twin-Track arch was designed to permit easy placement and removal. Attachments for holding the distraction device were welded onto the orthodontic wire avoiding the necessity of band cementation or other preoperative adjustments.
Citation: The Angle Orthodontist 76, 1; 10.1043/0003-3219(2006)076[0164:SMDOUA]2.0.CO;2
A custom-made, articulated palatal bar was specially developed to avoid the undesirable buccal tipping of the transported segment but permitting unrestricted rotational movement of the maxillary lateral segments (Figure 1C).
The Twin-Track labial arch was mounted onto the orthodontic appliance in the operating room after the complete maxillary Le Fort I osteotomy was performed with the patient under general anesthesia. The traction screws and traction microcables were placed six days postsurgically to allow for a latent period and initial callus formation before traction forces were applied. This facilitated postoperative management and feeding.
Surgical procedure
A three-piece (bilateral cleft) type transverse Le Fort I maxillary osteotomy and simultaneous alveolar bone graft were performed under general anesthesia with oro-tracheal intubation. Incisions were made and mucoperiosteal flaps were elevated. An insufficient bone bridge for tooth movement was observed on both sides of the alveolar clefts, resulting in clefts that tapered superiorly. Bone was removed with a bud-shaped burr to parallel the sides of the clefts to achieve complete cleft closure.
A premaxillary osteotomy was performed at the premaxillo-vomerine junction. The Le Fort I osteotomy of the lateral segments was performed by conventional methods. Each segment of the maxilla was mobilized completely but not advanced or repositioned. Mucoperiosteal flaps at the alveolar clefts were hinged and sutured to reconstruct the nasal floor. At this time, mobility of the dentoalveolar segments was verified to ensure that all bone resistance was released. Six grams of cancellous bone, harvested from the iliac crest, was inserted loosely into the preexisting alveolar cleft space bilaterally (Figure 3). No fibrocartilage envelope was observed around the leading edge of bone at the time of surgery. The defects were covered by mucoperiosteal flaps. The Twin-Track arch and the articulated palatal bar were mounted on the supporting teeth across the bilateral clefts, assisting stabilization of the maxillary lateral segments and premaxilla.
Citation: The Angle Orthodontist 76, 1; 10.1043/0003-3219(2006)076[0164:SMDOUA]2.0.CO;2
Distraction Protocol
Combined simultaneous distraction osteogenesis
A latency period of six days was allowed before initiating the combined simultaneous maxillary distraction. Simultaneous bilateral approximation of the alveolar clefts by bone transportation of maxillary lateral segments toward the cleft was performed with the TT device, whereas the maxillary advancement was carried out in combination with rigid external distraction (RED system, Martin LP, Jacksonville, Fla). The maxilla was advanced parallel to the functional occlusal plane (Figure 4).
Citation: The Angle Orthodontist 76, 1; 10.1043/0003-3219(2006)076[0164:SMDOUA]2.0.CO;2
The distraction device was activated daily until both ends of the alveolar cleft were approximated and satisfactory anterior overjet was obtained. Distraction was performed at the rate of one and 0.5 mm/d in two increments for the maxillary advancement and segmental transport, respectively. The patient remained in the hospital during the distraction period. Activation was performed by a single orthodontist. The duration of the activation period was determined clinically and cephalometrically by the severity of the midface retrusion and anterior dental crossbite. The patient follow-up was daily to assess progression of the distraction until the proper overjet, overbite, and relatively stable occlusion were achieved. The device was kept in place for three weeks for rigid retention after activation was completed. After this period, the patient returned to the clinic for removal of the cranial portion of the RED device. The Twin-Track arch was maintained for an additional two weeks to ensure a complete consolidation of maxillary segments and occlusal stabilization. There were no complications.
RESULTS
Complete closure of the alveolar clefts was achieved by the 10th day and maxillary distraction osteogenesis by the 13th day after initiating distraction (Figure 5). The concave facial appearance was improved with acceptable occlusion, and complete cleft closure was attained bilaterally (Figure 6). The distracted dental arch segments were moved bodily toward the cleft or defect, as revealed by the panoramic radiograph and cephalometric analysis. Controlled rotational movement of both lateral segments was obtained without buccolingual tipping of the dentoalveolar segment, indicating the efficacy of the articulated palatal bar. No adjustments were necessary in the vector of the transported segments during the activation of the TT device. No problems were encountered in the immediate postoperative stability of the occlusion.
Citation: The Angle Orthodontist 76, 1; 10.1043/0003-3219(2006)076[0164:SMDOUA]2.0.CO;2
Citation: The Angle Orthodontist 76, 1; 10.1043/0003-3219(2006)076[0164:SMDOUA]2.0.CO;2
Occlusal and panoramic films revealed the presence of new remodeled alveolar bone on the docking site bilaterally and at the nasal cleft space (Figures 7 and 8).
Citation: The Angle Orthodontist 76, 1; 10.1043/0003-3219(2006)076[0164:SMDOUA]2.0.CO;2
Citation: The Angle Orthodontist 76, 1; 10.1043/0003-3219(2006)076[0164:SMDOUA]2.0.CO;2
DISCUSSION
Distraction osteogenesis has been used recently to correct a wide range of craniofacial defects. In such patients, a severe maxillary deficiency may be accompanied by wide residual alveolar and maxillary clefting, palatal and oronasal fistulae, and scarring of the palatal and pharyngeal soft tissues, thus restricting treatment with conventional surgical/orthodontic approaches.1213 With current distraction protocols, it is possible to gradually advance a severe hypoplastic maxilla to the ideal horizontal and vertical positions1–3 and to perform the closure of wide alveolar clefts using both interdental8 and transport9 distraction osteogenesis with predictable and stable results. However, the simultaneous application of these methods has not been applied routinely because of the difficulty in achieving rigid and stable retention of the transported segments. Therefore, multiple surgical stages were needed to address severe maxillary deficiencies compounded by wide alveolar clefts and oronasal fistulae.
The plan to perform simultaneous maxillary distraction osteogenesis combined with bone grafting was developed because conventional approaches for approximating large clefts would not eliminate the need for secondary bone grafting in the nasal cleft space above the docking site.8–11 In addition, maxillary advancement was necessary to correct the anterior crossbite and harmonize the facial balance. Moreover, our patient was concerned about the necessity of additional surgery with conventional approaches using bone graft followed by implants and prosthetic teeth.
A treatment approach that would reduce the number of surgical procedures would be cost effective because it would obviate the need for implants and prosthetic teeth. Conventional treatment with bone graft before the surgery, followed by implants and prosthetic teeth, was proposed as an option to the patient. However, the patient was opposed to any artificial means.
As an alternative, a plan was developed to gradually advance the maxillary lateral segments toward the premaxilla to achieve closure of the bilateral clefts using Twin-Track distraction simultaneous to maxillary distraction osteogenesis with the RED system.
The maxillary lateral segments were distracted toward the cleft until the canines on the lateral segments were approximated to the central incisors on the premaxilla. Consequently, the previously inserted bone graft could be adjusted and remodeled according to the new cleft shape. The residual alveolar cleft was approximated completely by 10 days after initiating distraction. The maxillary distraction osteogenesis was completed by day 13 after initiating distraction. This approach combined the benefits of distraction osteogenesis and autogenous bone grafting. This procedure does not eliminate the bone graft, but it does eliminate a second surgery because the bone graft was combined with the first surgery. The cancellous bone graft was packed loosely into the alveolar cleft to create the mineralizing bone matrix for the segments to move through.
The technique of reduction of a wide alveolar cleft by distraction osteogenesis was demonstrated by Liou et al.8 In their technique, a custom-made, intraoral, tooth-borne distraction device was used to deliver the force to the osteotomized dental arch to minimize the alveolar cleft. Yen et al9 reported a case in which a large alveolar cleft was closed by transport osteogenesis of a posterior segment using orthodontic archwires attached to the bone. Dolanmaz et al,10 using a custom-made tooth-borne distractor for management of alveolar clefts, observed that the transported segment was docked in a more superior position at the end of the distraction process, consequently changing the inclination of the teeth in the transported segment. These authors obtained approximation of wide clefts. However, additional surgery for alveolar bone grafting was still necessary to close residual fistulae, perform gingivoperiosteoplasty, and graft the empty nasal cleft space above the transported segment.
The proposed Twin-Track distraction technique, based on the concept of track-guided bone transport, permits three-dimensional control over the distraction processes and allows simultaneous alveolar cleft closure and maxillary distraction combined with autogenous bone grafting. The transported segment is attached to double tubes and slides on the Twin-Track arch, which incorporates a variety of vectors and directions, according to the required outcome. No additional adjustments to the vectors of the transport segments are necessary during the distraction period. Moreover, the immediate placement of the Twin-Track arch and the articulated palatal bar after the surgical procedures were completed is extremely advantageous for providing rigid retention for the osteotomized segments. Because the segments may present with great mobility postsurgically, Twin-Track distraction assists the stabilization of the premaxilla and maxillary lateral segments. Consequently, this method avoids the collapse of the osteotomized segments, preserving the original maxillary dental archform. Twin-Track distraction has proved to be easy to implement and the chair-time required for the adjustment is minimal.
A potential complication of this procedure is the prevention of complete approximation of the lateral segments resulting from premature contact at the narrow part of the cleft as the segments are being transported. To avoid this problem, mobility of the osteotomized dentoalveolar segments needs to be verified to ensure that all bone resistance is released. A careful plan by the orthodontist and surgeon should be evaluated before the surgery to achieve optimum results. The proposed method eliminates additional surgery and other procedures but is dependent on additional hardware and appliances customized for the patient.
Wide clefts are difficult to graft and are frequently associated with a large palatal fistula that may become wider after orthodontic expansion. Segmental osteotomies with maxillary advancement, simultaneous fistula closure, and bone grafting have been performed successfully with rigid internal fixation,12–14 although large movements can compromise the flap closure and the blood supply to the osteotomized segment.
Simultaneous maxillary advancement and cleft closure combined with bone grafting technique has never been performed with distraction osteogenesis because of the complexity of movements involved and the difficulty in three-dimensionally controlling and stabilizing the transported segments. This limits its use in many patients who would otherwise benefit from this procedure.1–3
The combined use of the proposed Twin-Track distraction technique and the RED system has proved to have many advantages in treating cleft patients. By combining both methods, complex malformations can be corrected simultaneously in cleft patients. Refinements in these techniques should help expand the range of options available for craniofacial surgery and the range of indications for distraction as well as reduce the morbidity. A future communication will report treatment outcomes for the simultaneous correction of severe maxillary dysplasias associated with wide clefts with the use of a TT device.
CONCLUSIONS
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Simultaneous reduction of alveolar clefts, autogenous bone grafting, and maxillary advancement with distraction osteogenesis is a logical surgical approach for the management of a cleft lip and palate patient.
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This technique corrects severe craniofacial deformity with fewer surgical interventions and, consequently, less total treatment time than with current techniques.
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By grafting the preexisting wide alveolar defect with autogenous bone, the need for additional surgery after complete cleft closure is avoided.
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This procedure can be performed in a cost-effective manner with minimal morbidity while producing excellent patient compliance and satisfaction.
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A combination of TT device and the RED system can be used to achieve simultaneous closure of wide clefts/fistulae and advancement of a hypoplastic maxilla.
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By combining both methods, complex malformations can be corrected simultaneously with predictable results in cleft patients.
Presurgical and postsurgical photographs. (A) Presurgical palatal view of bilateral cleft site measuring five (left) and 12 (right) mm, respectively. (B) Presurgical frontal view of cleft. (C) Twin-track arch and articulated palatal bar assembled (presurgically). (D) Anterior view of the Twin-track arch showing no interferences
Diagram of the Twin-Track distraction device. (A) Labial view showing the osteotomy line (dotted line) and the Twin-Track labial arch. The distraction screw and cable are anchored into the main orthodontic wire. (B) After distraction, the maxillary lateral segments move toward the premaxilla until total closure of the clefts
Autogenous bone graft is inserted bilaterally into the cleft spaces
(A) Patient undergoing rigid external distraction. (B) External view of the traction screws of the Twin-Track distraction device combined with the traction hooks of a rigid external distraction system. (C) Intraoral view of a Twin-Track distraction assembly with traction microcables
(A) Postsurgical view of the cleft site. (B) Postdistraction view revealing the complete closure of the clefts. (C) Postsurgical palatal view showing the articulated palatal bar. (D) Postdistraction view showing complete closure of the bilateral clefts
Predistraction (A,C) and postdistraction (B,D) facial and cephalometric radiograph views show correction of facial concavity and anterior crossbite
(A) Presurgical occlusal radiograph. (B) Postdistraction occlusal radiograph after docking showing no residual cleft space above or between the bony segments
(A) Radiographic view of the dentition before distraction osteogenesis. (B) Radiographic view at the end of the distraction
Contributor Notes
Corresponding author: Eduardo Yugo Suzuki, DDS, PhD, Department of Orthodontics, Faculty of Dentistry, Chiang Mai University, Suthep Road, Amphur Muang, Chiang Mai 50200, Thailand (yugotmdu@hotmail.com)