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OBJECTIVES: The purpose of this investigation was to provide an in vitro evaluation of the effects of soft tissue and position on vector during distraction. MATERIALS AND METHODS: A polyurethane skull and mandible replica (Synbone, Landquart, Switzerland) was used in this study along with an internal distraction device (Synthes Maxillofacial, Paoli, PA). The first portion of the investigation evaluated the effects of distractor position (inferior body, midbody, and superior body) on distraction vector. The second portion of the investigation used polyethylene straps to simulate the suprahyoid muscles and muscles of mastication, and polysulfide to simulate periosteum and mucosa. A laser light source attached to the synthetic mandible was projected on a grid 7.1 m from the construct to measure deflection from the starting point. The distractor was advanced 8.0 mm for each trial. Five trials each for inferior, middle, and superior, with and without simulated soft tissues (N = 30) were performed. Vertical and horizontal deflection along with absolute distance were measured and recorded. Means and standard deviations were derived for groups, and compared for statistical significance (P <.05) with a 1-way analysis of variance for the effects of position with and without simulated soft tissue, and with a paired t-test for the effects of simulated soft tissue within groups of similar distractor position. RESULTS: Statistically significant differences (P <.05) for distractors without simulated soft tissues were only noted for vertical deflection between the inferior and superior distractor groups. Statistically significant differences were noted for all measures, for all distractor positions with simulated soft tissues. Statistically significant differences were noted for all measures between similar distractor positions with and without simulated soft tissues. Distractors without simulated soft tissues were deflected lateral to the y-axis and above the x-axis. Distractors with simulated soft tissues were deflected lateral to the y-axis, but below the x-axis. For distractors with simulated soft tissues, the closer to the inferior border, the less the deflection from the x-axis. CONCLUSION: Position alone had minimal effects on distraction vector. Simulated soft tissues affected the vector of distraction. The combination of position and simulated soft tissues affected distraction vector.
The case of a 1-year-old boy who underwent correction of a scaphocephalic deformity using distraction devices is described. Double pi-shaped osteotomies were cut. Bilateral temporal bone flaps were gradually expanded, and the frontal bone was pulled back simultaneously. The patient showed a good skull contour 2 years postoperatively. Although previous distractions were aimed only at expansion of the cranium, we used the distraction technique to successfully shorten the cranial vault in the anteroposterior direction. This case demonstrates that the osteotomized bone flaps can be moved in various directions. This feature of the distraction technique may contribute greatly toward meticulous reconstruction of the cranial vault.
Mandibular lengthening by distraction was performed in a 6-year-old severely affected Treacher-Collins syndrome patient who was tracheostomy dependent. As previously reported, this procedure permitted tracheostomy removal once distraction was complete. Now that the patient is skeletally mature, the long-term results of this intervention are reported with regard to his clinical outcome and an assessment of the anatomical changes in the upper airway during growth. Although the distraction could be considered a success in that it enabled permanent decannulation and improved the minimum cross-sectional area of the upper airway, there was no further increase in the minimum cross-sectional area of the upper airway during childhood growth. It is significant that the abnormal growth pattern of the mandible, which is characteristic of this syndrome, did not alter from its preoperative pattern once distraction was completed.
To better study the effects of limb lengthening on skeletal muscle, the authors developed a rat model that uses a miniature external skeletal fixator applied to the tibia of an adult Sprague-Dawley rat. The mounting and lengthening protocols follow the principles developed by Ilizarov. With the initial version of the fixator, the rats had progressive equinus contractures develop because the calf muscles resisted elongation. By incorporating a footplate in the distraction apparatus, tibial lengthening can be achieved without concomitant equinus.
We compared the effectiveness of transcutaneously activated magnetic distraction of an osteotomized cranial bone flap to surgical repositioning of the flap with immediate, rigid internal fixation. Thirty immature rabbits were studied. All 30 rabbits underwent complete circumferential osteotomies of both parietal bones and postoperatively all were fitted with head frames. The rabbits were divided into 4 groups. The experimental magnetic distraction group consisted of 10 animals (group 1). In these rabbits magnets were secured to both parietal bones and magnets of opposite polarity were placed in the headframes. Each morning, the magnets in the head-frames were moved 0.25 mm farther away from the skull; this continued for 20 days for a total setback of 5 mm. Five animals served as the magnetic distraction controls; in these animals magnets were placed on the parietal bones but none were attached to the headframes (group 2). The experimental surgical repositioning group consisted of 10 rabbits (group 3). In each the parietal bones were elevated and fixed 5 mm above the rest of the skull using vitallium mesh and screws. Five rabbits made up the surgical respositioning control group (group 4). In these animals, parietal osteotomies were performed but the bones were secured to the skull in their original positions using hardware identical to that used in the experimental group. Six weeks later all of the animals were sacrificed. Two significant differences were identified between the experimental groups: (1) the cranial contours of the animals in the magnetic distraction group were rounded while those of the surgically repositioned group were acutely angled; (2) the osteotomies in rabbits in the magnetic distraction group were essentially completely ossified while in rabbits in the surgically repositioned group there were obvious gaps at the osteotomy sites that were filled with fibrous tissue. These conclusions support the potential utility of magnetically activated distraction as an alternative to current methods of cranial vault remodeling.
We have developed a new internal distraction device for the transport of bone, which comprises a bridging reconstruction plate, a bracket with miniplates for fixing the transport disc, a traction mechanism, and traction wire. The entire device except for part of the traction mechanism is placed internally. Activation of the traction mechanism slides the bracket on the rail of the reconstruction plate with the traction wire, which carries the transport disc along the rail. The traction mechanism can be removed after the period of distraction, leaving only the other components during consolidation.
This case demonstrates the successful aesthetic and functional reconstruction of a complex facial gun-shot injury with extended bone defects and soft tissue destructions using a 3-step procedure. Initially, a reconstruction plate was inserted, later a fibula transplant enabled the basic reconstruction and finally was distructed in a 3rd session. The rationale behind the sequencing of surgical sessions was the extended bony defect and soft-tissue destruction. The main problem in this type of wound is hypoxia or anoxia of the receptor bed for the transplant. A microvascular anastomosized bone transplant is necessary for sufficient oxygen tension in the recipient site. The anatomical dimensional disproportion of the transplanted free fibula graft and the shape of the mandible were corrected prior to the insertion of dental implants by means of vertical distraction.
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Therapeutic ultrasound is known to enhance bone-fracture healing. The purpose of this article was to study the effect of therapeutic ultrasound on mandibular incisor development and eruption in 15 skeletally mature male New Zealand white rabbits undergoing mandibular osteodistraction. The surgical cuts were made anterior to the molars and consequently transected the mandibular incisors. The animals were divided into 3 groups of 5 rabbits each. Group I received ultrasound on both sides of the mandible every other day. Group II received ultrasound on the left side of the mandible every day. Group III did not receive ultrasound. Ultrasound was given for 20 minutes per application. Mandibular incisor eruption was measured directly on the rabbits and on lateral head radiographs. The animals were killed 4 weeks after surgery, and dissected mandibular specimens that contained the incisor segments were evaluated histologically. The lengths of the tooth segments increased in the ultrasound-treated animals, compared with the controls (group III). However, the rabbits in group II had greater increases in length of the mandibular incisor segments than those in group I. Histologic examination showed that the newly formed tissues at the distraction site and at the cut ends of the incisor segments consisted of osteodentin-like tissue and cementum. Thus, therapeutic ultrasound combined with distraction enhanced mandibular incisor growth and eruption.
Purpose: The purpose of this study was to observe developing teeth in a lengthened mandible after distraction. Material: Ten mongrel dogs with deciduous dentitions were used. Methods: A corticotomy was carefully made around a tooth bud and the external distractor (Orthofix M-100((R))) was connected. After a 5-day latent period, distraction was started at a rate of 0.75 mm per day for 10 consecutive days. Then, the lower jaw was stabilized by an external fixation to allow ossification. While the operation was performed on the left side (Distraction group), the contralateral side was studied for comparison (Control). In addition, a corticotomy, artificial fracture and external fixation were carried out to confirm the influence of the operation (Fracture group). Then macroscopic, radiographic and histological evaluations were carried out. Results: In the Distraction group, the space between the wall of the dental follicle and the crown expanded as distraction began. The end of the calcified root became wider and irregular during the distraction period, and finally, the apex closed. In the Fracture group, the teeth erupted although slight alterations of the root shape were observed in association with the operation period. Conclusion: The root became irregular, but the teeth erupted within the distraction area. Copyright 2001 European Association for Cranio-Maxillofacial Surgery.
Shortening of one or more metatarsals may be a cause of metatarsalgia and painful toe deformity. Usually, symptoms are limited and may be successfully addressed with nonoperative treatment. Rarely, operation indicated. This report reviews the surgical techniques, results, and complications. These operations include osteotomy and one-stage distraction with bone grafting, osteotomy and one-stage distraction without bone grafting, osteotomy with gradual distraction and bone grafting, and osteotomy with gradual distraction without bone grafting.
In this article a young, still growing female patient with a Class II division 1 malocclusion and a short mandible is presented. She was treated with functional and fixed orthodontic appliances. During orthodontic treatment with fixed appliances, mandibular lengthening by means of the intra oral distraction technique was used to correct the jaw relation. The orthodontic treatment could be finished successfully after lengthening of the mandible. The results are presented. In the discussion some alternatives for mandibular distraction are mentioned. It was concluded, that intra oral mandibular distraction is useful and successful, in selected cases.
Up to now the clinical follow-up in mandibular callus distraction was supported by radiologic methods, although low-mineralized structures are only insufficiently described by X-rays. Mandibular callus distraction was performed on 14 patients suffering from uni- or bilateral mandibular hypoplasia, using either intra- or extraoral devices. The clinical follow-up was supplemented by standardized sonographic investigations. With the exception of postoperative pin placement control, which was done by using X-rays, all interesting items of treatment could be visualized by sonography. We found a reliable correlation between sonographically measured distances and distances measured on the device. Due to early detection of complications, a premature ossification was detected in one case and an infection was diagnosed in another, using ultrasound. Sonography proved to enhance the possibilities of monitoring in mandibular callus distraction treatment and can be recommended in clinical routine.
Mandibular distraction was performed on 14 children, between September 1991 and December 1997. Their average age was 6.9 years, ranging from 1.5 to 13.5 years. All patients had severe hypoplastic mandibles with retromandibulism. Seven of the children (50%) had respiratory distress due to obstruction of the upper airway before distraction. This resolved in every case. Five patients underwent unilateral and nine bilateral distraction. A total of 23 distractors were used, 15 were applied extraorally and 8 endorally. The average latency time after operation was 2.8 days, but for the past 2 years, distraction was started beginning with the operation. The distraction was increased twice daily for an average of 5.5 weeks, by 0.4 or 0.5 mm each time, depending on the distractor. Computed tomography and ultrasound were used to follow the ossification process in the distraction gap and to measure the lengthening achieved. Subsequent retention time averaged 2.4 weeks. The mandibles were elongated by up to 18 mm (average 9.3 mm) and the respiratory distress symptoms resolved in all patients. Several minor complications which are reported occurred. Six patients were followed up for periods between 3 and 7 years. During this time further growth of the distracted mandibles was recorded.
Corticotomy of the tibia using Ilizarov's anterolateral approach is used routinely for callus distraction. This method is associated with impaired callus formation and delayed healing because of marginal soft tissue covering and blood supply to the proximal tibia. We presumed a newly designed posteromedial approach would result in less callus defects and improved healing. In this prospective, randomized study, 31 patients had callus distraction using an anterolateral approach or the newly designed posteromedial approach. Callus formation was assessed radiographically and histologically. Callus defects were classified using serial radiographs. Biopsy specimens were taken from high-grade defect (Grades 3-4) zones to examine the osteogenic potential. Radiographic evaluation showed 13 callus defects; 12 occurred after the anterolateral approach and only one occurred after the posteromedial method. Although low-grade defects (Grades 1-2) healed spontaneously, biopsy specimens taken from Grades 3-4 defects revealed no osteogenic potential and requiring operative revision. Because of low soft tissue covering and impaired blood supply to the anterior tibia during surgical exposure for corticotomy, less callus formation occurred after the anterolateral approach compared with the posteromedial approach. We recommend the less invasive posteromedial approach to reduce callus defects and impaired healing in callus distraction of the proximal tibia.