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In this pilot study, the principle of distraction osteogenesis to advance the anterior maxilla of the dog was used. After an anterior maxillary osteotomy, the anterior segment was advanced 10 mm in 10 days. Soft and hard tissue formation resulted in complete healing across the distraction gap without a soft tissue defect.
This scanning electron microscopic study examined the spatial and temporal features of proliferating vessels of regenerating bone tissue and blood supply during distraction osteogenesis. A rat model of tibial lengthening was used with a protocol divided into a latency period of 7 days, a distraction period that lasted 14 days with a daily distraction rate of 0.5 mm in two steps, and a consolidation period of 21 days. Vascular casting was done on the hindlimbs before osteotomy and on postoperative days 7, 14, 21, 28, and 42. Scanning electron microscopic findings were correlated with radiological and histological observations. On days 7 and 14, the proliferation of periosteal vessels was pronounced and there was distinct subperiosteal bone formation on the osteotomized surfaces. On day 21, vascular branches from the medullary canal of the host bone formed a vascular network, which gave rise to multiple axial, straight vascular branches, running parallel to the direction of distraction, toward the interzone, in accordance with the progress of mineralization. On day 28, the periosteum provided vascularization to the peripheral side of the interzone whereas the center of the interzone was still relatively avascular. On day 42, the periosteal and medullary vascular channels were completely connected at the distraction site including the interzone, which was occupied by developing and mature bone trabeculae. These results suggest that vascular proliferation occurs actively during the latency and distraction periods and then gradually decreases over time. A close temporal and spatial relationship exists between formation of regenerated bone and vascular proliferation of the periosteum and medullary canal.
BACKGROUND: No study has systematically evaluated the effect of distraction osteogenesis on the gingival tissues. Therefore, this study was designed to analyze the newly formed bone and gingiva during the consolidation period of mandibular osteodistraction using standard histologic techniques. METHODS: Seventeen skeletally mature male beagle dogs underwent 10 mm of bilateral interdental mandibular lengthening. After distraction, the regenerates were allowed to consolidate for 0, 2, 4, 6, or 8 weeks, then the animals were sacrificed and tissues harvested for analysis. RESULTS: Mineralization began at the host bone margins at the end of the distraction period, followed by a progressive increase in bone surface area, with a concomitant decrease in fibrous tissue. The gingiva initially underwent mild inflammatory and reactive changes during distraction and during the first few weeks of consolidation. The rate of bone formation gradually increased from the end of distraction to the fourth week of consolidation, at which time it remained constant until sometime before the eighth week, when it tapered off slightly as remodeling began. From the second through the eighth week of consolidation, regenerative changes and neohistogenesis were seen in the gingival tissues. CONCLUSIONS: Osteodistraction has the potential to drastically decrease the total treatment time for alveolar bone augmentation prior to dentoalveolar implant placement since the regenerate bone rapidly mineralizes within approximately 8 to 10 weeks after the distraction period and the gingiva responds favorably to increased length by regeneration rather than by degeneration. Although the results appear favorable, similar data should be evaluated in human clinical trials.
PURPOSE: To evaluate the clinical results of post traumatic complications treated by the author's own technique using an AO/ASIF conventional external fixator (without special distraction device). MATERIALS AND METHODS: There were 70 patients (77 limbs) with an average of 26.8 years (range, 4-54). There were 33 femurs, 43 tibias and one ulna. The following post traumatic complications were treated: 14 limb shortening, 20 nonunion, 28 malunion 14 infected open fractures with bone loss and 1 chronic osteomyelitis. Linear lengthening was performed in 29 limbs, acute de-rotation and subsequent lengthening in two limbs, gradual angular correction in six limbs, combined gradual angular correction and subsequent lengthening in 10 limbs, combined acute angular correction and subsequent lengthening in eight limbs and 22 limbs with bony defects were treated with the technique so-called "bone transportation". All of the limbs were treated with an AO/ASIF conventional external fixator, using the author's own technique with distraction rate of 1 mm in one step on alternate day (1 mm/48 h). RESULTS: A new bone formation in the distraction gap was achieved in 73 of the 77 limbs. Four cases without consolidation were successfully treated with an iliac bone graft combined with plating or reapplication of the external fixator. Average new bone formation was 5.6 cm (range, 1-17 cm). The average follow-up period was 10.8 months (range, 1-71 months) after removal of the fixator. The average healing time was 244.7 days (range, 60-836 days) and the healing index was 50 days/cm (range, 17-100 days). In the group with associated angular deformity the mean correction was 18.5 degrees (range, 10-40). CONCLUSIONS: The author's technique of distraction osteogenesis, using a conventional external fixator combined with a distraction rate of 1 mm/48 h (1 mm/step) adequately treated the post traumatic complications. No extra equipment was needed other than readily available AO/ASIF fixation systems. The described technique, using an AO/ASIF fixator as a lengthening apparatus was simple and cost-effective.
Seven children with facial asymmetry, mean age 12 years (range 11-14.5) were treated by intraoral distraction osteogenesis to lengthen the hypoplastic ramus. We achieved a mean increase in length of the ramus of 13mm (range 10-16). In only one patient did we achieve a posterior open bite on the distraction side. All patients ended with a symmetrical chin. It was helpful to place an orthodontic bite block on the opposite side either preoperatively or postoperatively to cant the plane of occlusion. The duration of follow-up was too short to allow conclusions to be drawn about the future requirement for bimaxillary osteotomies.
PURPOSE: The purpose of this article is to describe the method for reconstructing patients with severe anterior maxillary defects, using a combination of distraction osteogenesis, onlay bone grafts, and implants to support either fixed or fixed/removable prostheses. MATERIALS AND METHODS: The surgical technique involves placement of an extraosseous distraction device followed by greater than 10 mm of distraction of the alveolus. A corticocancellous graft is harvested from the hip to establish sufficient horizontal bone for implant placement. Implants are placed after graft consolidation followed by fabrication of a fixed or fixed/removable prosthesis depending on the needs of the individual patient. RESULTS: Five patients have been prospectively followed using this technique, with completion of their prosthetic reconstruction, with follow-up ranging from 1 to 4 years. CONCLUSION: The combination of distraction, onlay bone grafting, and implant placement has been able to reconstruct patients with severe maxillary defects.
BACKGROUND: Chronic ethanol exposure inhibits the rapid bone formation demonstrated during limb lengthening by distraction osteogenesis (DO). This inhibition is attenuated by simultaneous administration of antagonists to the cytokines interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha. The individual effects on inhibition of osteogenesis by these cytokines were tested. We hypothesized that administration of individual antagonists to these cytokines [IL-1 receptor antagonist (IL-1ra) or polyethylene glycol-conjugated soluble TNF receptor type 1 (sTNFR1)] would enhance DO and that the individual administration of each cytokine [recombinant rat (rr) IL-1 or recombinant rat (rr) TNF] would inhibit DO. METHODS: Rats were either infused with a liquid diet with or without ethanol (antagonist studies) or given rat chow (recombinant studies) and underwent tibial fractures stabilized with external fixators for DO. The bioactive substances were administered by systemic (antagonist studies) or local (recombinant) diffusion. RESULTS: A comparison of histologic sections from these distracted tibias demonstrated a protective effect on bone formation by sTNFR1 (p<0.05), unexpectedly, an IL-1ra-related decrease in bone formation (p<0.02), significant decreases in bone formation with rrTNF compared with the vehicle controls (p<0.02), and no significant changes in bone formation with rrIL-1. The cellular responses (fibroblastic and inflammatory cells) were unique for each recombinant cytokine administered. CONCLUSIONS: These results suggest that the osteoinhibitory effects of chronic ethanol exposure are mediated in part by the TNF signaling axis.
PURPOSE: This study evaluated horizontal distraction of the narrow alveolar ridge in dogs and the possibility of achieving osseointegration of implants placed into the distracted site during a consolidation period. MATERIALS AND METHODS: Six beagle dogs weighing approximately 9 to 10 kg were used in this experiment. Twelve weeks after extraction of the mandibular premolars, horizontal alveolar ridge distraction was performed using an originally designed lengthening apparatus. Twelve days after the completion of distraction, screw-type implants were placed into the distracted site. RESULTS: Twelve weeks after the placement of implants, thin lamellar bone rose horizontally from the transport segment toward the surface of the implant. Twenty-four weeks after their placement, the implants were fully embedded in mature lamellar bone, and direct bone contact with the implant surface could be seen. DISCUSSION: Horizontal alveolar ridge distraction was performed successfully by using a lengthening apparatus in the narrow alveolar models. Osseointegration was achieved even though the implants were placed into the distracted site during the consolidation period. CONCLUSION: Horizontal alveolar ridge distraction can be a beneficial technique in the placement of implants In the narrow alveolar ridge in the dog population.
Two cases of lengthening of metatarsals by distraction osteogenesis are reported. One of these cases is an acquired deformity of the first metatarsal; the other is a congenital short fourth metatarsal. By following the principles set forth by Ilizarov, it was possible to lengthen the metatarsal bones and surrounding soft tissues without open lengthening of tendons or secondary bone grafting of the distraction gap. We believe this method is an improvement over previously described methods of metatarsal lengthening.
During limb lengthening gradual reconstruction of bone tissue in distraction gap requires constant, systematic control and evaluation. This process is depicted descriptively and subjectively. Changes happening during osteogenesis are dynamic, they can stop, slow down or accelerate, and regenerate may be of various shape and form. In this work different methods of bone regenerate evaluation are presented. They may be divided on two basic groups. First group contains methods with X-radiation, and the second - without X-rays. Examinations that evaluate arising bone regenerate may be also divided on descriptive examinations and quantitative. Despite that different methods are used for distraction osteogenesis course estimation, classic radiological examination remains the basic one. The rest of them are most often supplementary examinations, useful in selected stages of treatment, for e.g. ultrasonography in first stage of regenerate arising. So it seems, that future is in quantitative regenerate evaluation using radiographs. Classic X-ray picture made in reproducible and repeatable conditions may be subjected to digital, quantitative image analysis, and acquired results enables for more precise and more balanced evaluation of new bone formation in distraction osteogenesis.
BACKGROUND: This study was performed to determine the safety and effectiveness of lengthening of the tibia, in patients who have a limb-length discrepancy or a short stature, with use of distraction osteogenesis, a technique based on the principle of distracting the callus that is formed after a subperiosteal osteotomy of the proximal portion of the diaphysis of a long bone. METHODS: A total of 230 tibial lengthening procedures were done in 150 patients. Seventy procedures were performed because of a limb-length discrepancy, which was secondary to trauma (thirty limbs), congenital fibular hemimelia (twenty-six), poliomyelitis (ten), or infection (four). The remaining 160 procedures were performed because of a short stature, which was secondary to achondroplasia (fifty-eight limbs), Turner syndrome (thirty-four), an idiopathic etiology (twenty-two), hypochondroplasia (twenty), achondroplasia (ten), Ellis-van Creveld syndrome (six), rickets (four), or adrenogenital syndrome, Laron syndrome, or pseudoachondroplasia (two limbs each). The age of the patients at the time of the operation was 18.4+/-6.2 years (average and standard deviation), with a range of six to forty-one years. The procedures were performed according to one of three protocols. In Group A (ninety procedures), an Orthofix telescopic fixator and a variable number of screws were used and the tibiofibular syndesmosis was not stabilized; in Group B (ninety-six procedures), an Orthofix reconstruction system was used, the syndesmosis was stabilized, and a tenotomy of the Achilles tendon was performed; and in Group C (forty-four procedures), an Orthofix Garches lengthening device was used, the syndesmosis was stabilized, and a tenotomy of the Achilles tendon was performed. RESULTS: At the time of the latest follow-up (average, five years; range, two to seven years), the average gain in length after the seventy procedures performed because of a limb-length discrepancy was 4.0+/-1.98 centimeters (range, 2.5 to 9.5 centimeters), or 14 percent (range, 7 to 45 percent). The average gain in length after the 160 procedures that were performed because of a short stature was 7.8+/-2.28 centimeters (range, 2.5 to fifteen centimeters), or 33 percent (range, 10 to 78 percent). Ten (14 percent) of the seventy procedures performed because of a limb-length discrepancy and forty-six (29 percent) of the 160 performed because of a short stature were associated with a complication. There was only one permanent sequela in the entire series. CONCLUSIONS: Although the three operative protocols resulted in similar healing indices, the rates of complications differed significantly among the groups (p<0.0001). Group C (the Garches device) had the lowest rate of complications (7 percent). It is important to be aware of potential complications as well as the need for additional procedures in order to avoid predictable problems. These procedures include percutaneous tenotomy of the Achilles tendon and fixation of the distal segment of the fibula to the tibia to maintain the integrity of the tibiotalar articulation and the alignment of the foot.
OBJECTIVE: The purpose of this study was to observe the roentgenographic characters of distraction osteogenesis (DO) correction of cleft palate (CP), to study the expression of BMP proportional to fixation period time intervals, and to explore the new bone formation mechanism in Cleft Palate bone shelf. METHODS: 12 cats were used to establish the CP animal model surgically, and then were assigned randomly to (1) Experimental group (12 cats): CP defects were DO repaired at the rate and rhythm of 0.4 mm x 2/day. Specimen retrieval at 2, 4, 6, 8, 12 weeks after completion of distraction, roentgenography and Anti-BMP immunohistochemistry studies were performed; (2) Experimental control group (2 cats): CP defects without any treatment procedures, and (3) Empty control group of 2 cats. RESULTS: Anti-BMP immunohistochemistry study showed positive DAB dye in early 2 weeks and most extensively positive expression of BMP in 4 to 6 weeks. The expression of BMP wore off gradually through 8 to 12 weeks. The roentgenography showed that the newly mineralized bone was developed from the cut bone edges bilaterally to the central transparent zone, and the newly formed bone bridged the defect area completely at the end of the study. The CP bone defect was reconstructed and the distraction gap was filled with de nove osteogenesis. No new bone formation was observed in experimental control group. CONCLUSION: The process of new bone formation in the distraction area is dynamic. Being stimulated primarily, the process was kept highly active till quiescence phase finally. The X-ray examination shows that there is distinctively low roentgenopeque. Nevertheless, roentgenography is so far a very effective and convenient method to evaluate and monitor the DO correction efficiency.
OBJECTIVE: To compare speech outcome and velopharyngeal (VP) status of subjects with repaired cleft palate who underwent either conventional Le Fort I osteotomy or maxillary distraction osteogenesis to correct maxillary hypoplasia. DESIGN: Prospective randomized study with blind assessment of speech outcome and VP status. SUBJECTS: Twenty-two subjects were randomized into conventional Le Fort I osteotomy and Le Fort I distraction groups. All were native Chinese (Cantonese) speakers. METHOD: Perceptual judgment of resonance and nasal emission, study of VP structures by nasoendoscopy, and instrumental measurement by nasometry. Assessments were performed preoperatively and at 3 months postoperatively. MAIN OUTCOME MEASURES: Assessment of VP closure, perceptual rating of hypernasality and nasal emission, nasalance, and amount of maxillary advancement. RESULTS: There was no statistical difference in any of the outcome measures between the 10 subjects with conventional Le Fort I osteotomy and the 12 subjects with maxillary distraction: hypernasality (chi-square = 3.850, p = 0.221), nasal emission (chi-square = 0.687, p = 0.774), VP gap size (chi-square = 1.527, p = 0.635, and nasalance (t = -0.145, p = 0.886). There was no correlation between amount of maxillary advancement and any of the outcome measures (p = .05 for all). Changes in VP gap size and resonance are described. CONCLUSION: Results need to be interpreted with caution because of the small sample size and early follow-up. However, this study utilized an assessment protocol involving a variety of outcome measures and careful consideration of reliability factors, which can be a model for further and follow-up studies.
INTRODUCTION: The authors present the results of nine patients (two females, seven males) who had bone tumors that were treated with en bloc resection and distraction osteogenesis between 1991-2000. MATERIALS AND METHODS: The average age of the patients was 19.3 years (14-42 years). The histological diagnosis was osteosarcoma in four cases, Ewing's sarcoma in two, giant cell tumor in one, osteofibrous dysplasia in one and osteoblastoma in one. A uniplanar external fixator was applied to one case and circular external fixator to the other eight cases. RESULTS: The average follow-up period was 59.1 months (27-129 months). The external fixator was removed at an average of 18.1 months (range, 4-19 months). The average bone defect after resection was 14 cm (8-24 cm) and the average external fixation index, distraction index, and maturation index were 31.5 (18.7-40.0), 11.2 (10.9-11.2) and 17.8 (7.5-32.7), respectively. The function of the affected leg was excellent in four patients, good in three, fair in one and poor in one according to the Enneking scoring system. We did not observe any early consolidation or osseous binding in the defect area in any patient. Frequent complications were pin tract infection and non-union at the docking site. CONCLUSION: Our results indicate that the Ilizarov method allows effective restoration of bone defects in the treatment of bone tumors despite various disadvantages.
The aim of this study was to evaluate the feasibility of transoral bimaxillary distraction osteogenesis before releasing temporomandibular joint (TMJ) ankylosis using intraoral mandibular distractors. Nine patients (5 males, 4 females) aged 14-35 (mean 19) years were included. A bilateral Le Fort I osteotomy was performed together with a mandibular osteotomy on the affected side(s). An intraoral distractor(s) was inserted in the lower jaw, followed by an intermaxillary fixation (IMF) to maintain preoperative dental occlusion. The distractor was activated, after a latency period of 5-7 days, 2 times daily by 0.5 mm. There followed a consolidation period of 6-8 weeks. TMJ ankylosis was then released via a peri-auricular incision, a gap arthroplasty was performed, and mandibular movement was established after removal of the IMF and distractor. Optimal results were achieved clinically and radiologically with minimal relapse and complications. Apart from minor complaints, the distraction process was smooth and tolerable in all cases. Total mandibular elongation ranged from 17 to 25 mm (20.7 mm). Occlusal canting decreased to 0 degrees in 7 patients and to 1 degree in 2 patients (mean 0.2 degrees). After a mean follow-up period of 17 months, a mean postoperative mouth opening of 34.7 mm was achieved (0.6 mm preoperatively) and no re-ankylosis was detected. Intraoral distraction of a deformed mandible and maxilla before releasing TMJ ankylosis is a feasible and perhaps advantageous technique.
If treatment fails, mandibular hypoplasia, especially in unilateral cases, can cause severe facial asymmetries that worsen as the patient ages. Even distraction osteogenesis becomes more important as an early treatment concept, with regard to traditional therapies in a unidirectional application, if skeletal malformations are treated incompletely. In most cases of mandibular hypoplasia there are bone deficits in the vertical, horizontal and transverse direction, which lead to various problems in the skeletal profile. Therefore, we developed a multidirectional distractor to normalize a hypoplastic mandibular area in an almost anatomical manner. This device consists of two geared rods with a infinitely variable ball joint. It enables us to create one or two callus fields on each side and correct the profile on several levels. This is the decisive advantage in comparison with the intraoral devices that work only in one plane. Using a clinical example, the indication, technique and possibilities of multidirectional callus distraction are illustrated and discussed.
BACKGROUND: The purpose of the study was to investigate the morphologic changes of distraction osteogenesis performed on the mandible in growing minipigs. METHODS: Eighteen piglets were divided into four groups. In group A (n = 6), animals received unilateral osteotomy and the distractor device was activated for 2 weeks after a 1-week latency period. In group B (n = 6), animals underwent the osteotomy procedure and distractor placement. In group C (n = 3), animals received the distractor, and in group D (n = 3), only four reference pins were placed. After completion of distraction, the head portions were sent for computed tomography scanning. The coordinates of each selected mandibular landmark were recorded on three-dimensional computed tomographic reconstruction images for further mathematical linear and angular measurements to quantify morphologic changes. RESULTS: The sagittal length related to gonial region was increased in group A but decreased in group B. Although all groups had the tendency of increased ramus width, it was only significant in group B. The distraction also reduced the gonial angle and elevated the ramus inclination to the Frankfort horizontal plane at the operated side. On the contrary, osteotomy alone opened the gonial angle and flattened the ramus inclination. CONCLUSIONS: Distraction could lengthen the mandibles in growing minipigs by reducing the gonial angle and displacing the mandible posteriorly. This effect, which allows for developing a prominent gonial angle, could be further explored in treating syndromic patients with the deficiency in the gonial region. A greater amount of overcorrection should be considered while treating growing patients because the mandibular osteotomy procedure itself seems to retard the growth.
Over the last 50 years, Ilizarov refined a method to successfully lengthen endochondral bones and the surrounding soft tissue matrix. Given the difficulties in reconstructing deformities of the craniofacial complex, distraction osteogenesis has recently been used to avoid the problems associated with conventional surgery and to begin correction at an earlier age. Distraction devices can be categorized by whether they are internal or external, the direction of distraction, and the site of application. External devices are capable of either unidirectional, bidirectional, or multiplanar (three-dimensional) distraction. Internal or intraoral distractors are capable of unidirectional distraction only. Distraction devices used to lengthen the mandibular ramus and body, widen the mandible, augment the alveolar ridge, conduct bone transport, and advance the midface are reviewed.