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Acute correction and distraction osteogenesis for the malaligned and shortened lower extremity.

In limbs with combined shortening with angulation or malrotation, deformity may be quickly or slowly corrected before lengthening with external fixation. We examined a series of 35 patients with 40 limbs that underwent acute deformity correction and subsequent gradual lengthening. The average deformity corrected was 19 degrees, with subsequent average lengthening of 4.1 cm. Good radiographic callus formation was noted in 34 of the 40 segments studied. The magnitude of deformity correction had no effect on the quality of lengthened bone, incidence of complications, or the healing index. Skeletally mature segments had statistically significant decreased bone formation (p = 0.001), increased prevalence of callus complications (p = 0.001), and a higher healing index (p = 0.003). Based on this experience, it is our conclusion that immediate correction and lengthening is suitable in children and adolescents who have malaligned and shortened lower extremities. Because of poorer results in older patients, we believe that other techniques should be considered in adults.

Adolescent↗
PubMed2001

Facial symmetry after distraction osteogenesis and orthodontic therapy.

The purpose of this study was to document changes in the facial symmetry of patients with severe hypoplastic mandibles treated with distraction osteogenesis and orthodontic therapy. Ten patients (5 males and 5 females), ages 7 to 22 years, underwent unilateral mandibular distraction osteogenesis with extraoral distracting devices. Orthodontic therapy was initiated after the completion of mandibular lengthening. The mean follow-up period was 25.5 months. Posteroanterior cephalograms were traced before distraction, 6 months after distraction, and at a later follow-up appointment. Displacement of the chin point (in millimeters) and the midpoint of the mandibular incisors, the piriform angle, the intergonial angle, the occlusal cant to the horizontal line (in degrees), the ratio of linear measurements (in millimeters) Co-Gn, Co-Go, and Go-Gn of the affected to the nonaffected side, CoA'-Mid to CoA-Mid, and GoA'-Mid to GoA-Mid were compared. At the latest follow-up appointment, patients defined as having a successful result had a mean occlusal cant of 1.25 degrees, an intergonial angle of 2.13 degrees, and a piriform angle of 2.63 degrees. The mean displacement of the chin point to the midline was 1.5 mm and that of the mandibular central incisors to the midvertical line was 1.38 mm. The results indicated improvement in all patients.

Adolescent↗
PubMed2004

[Efficiency of low-intensity pulsed ultrasound on distraction osteogenesis in case of delayed callotasis -- clinical results].

AIM: Low-intensity pulsed ultrasound has been proven to accelerate fracture healing both clinically and experimentally. In this study the influence of low-intensity pulsed ultrasound during distraction-osteogenesis in case of delayed callotasis was investigated. METHOD: 20 patients could be included in this study. 16 patients initially were treated because of fractures of the lower leg, 2 because of fractures of the femur with resulting shortening of the afflicted limb. One patient suffered from chronic osteitis at the thigh and one from chronic osteitis at the upper arm without previous trauma. Because of delayed callotasis an adjunctive ultrasound treatment device was transcutaneously applied (frequency 1.5 MHz, signal burst width 200 microseconds, signal repetition frequency 1.0 kHz, intensity 30 mW/cm (2)) with the transducer placed at the distraction zone for 20 minutes daily. In all cases in-home treatment was performed. Evaluation was done by radiographic and sonographic controls of the distraction zone during examination of all patients at the outpatients' department every 3-4 weeks. RESULTS: Progress of callotasis was achieved in 15 out of 20 patients. Patients who were smokers during ultrasound therapy showed lower healing rates than those who never smoked. 2 patients suffering from osteitis of the tibia and missing callotasis had to be amputated. 3 other patients needed additional operative treatment including cancellous bone grafts because of missing new bone formation. Negative effects of low-intensity pulsed ultrasound during therapy could not be detected. CONCLUSION: We conclude that ultrasound treatment can accelerate bone maturation and formation in distraction osteogenesis, sometimes even in states of poor callotasis. It may provide a method of great promise in cases where delayed bone formation during distraction osteogenesis occurs.

Adult↗
PubMed2005

Effect of recombinant human bone morphogenetic protein 7 on bone density during distraction osteogenesis of the rabbit mandible.

OBJECTIVES: To examine whether the quality of bone generation in distraction osteogenesis of the rabbit mandible is enhanced by administering recombinant human bone morphogenetic protein 7 (rhBMP-7) to the lengthened site at the end of the distraction phase. STUDY DESIGN: Prospective randomized study of 24 rabbits undergoing distraction osteogenesis of the mandible, followed by injection of rhBMP-7 or a lactate buffer. SETTINGS: McGill University animal care facility. METHODS: Twenty-four white New Zealand rabbits underwent unilateral mandibular osteotomy and application of an Orthofix uniplanar M-100 fixator (Orthofix Inc., Verona, Italy) to the mandible. Mandibular distraction was carried out for 3 weeks. The animals were divided into three groups: group 1 (eight rabbits), control group: distraction, no injection; group 2 (eight rabbits), study group: distaction + injection of 200 microg of rhBMP7-lactate buffer; group 2 (eight rabbits), comparison group: distraction + injection of lactate buffer. All rabbits were sacrificed 7 weeks after surgery. The mandibles underwent radiology and bone densitometry analysis. MAIN OUTCOME MEASURES: Radiology assessment of bone generation within distracted segments and objective analysis of bone mineral density. RESULTS: Radiology confirmed the presence of bone generate within distraction sites. Densitometry showed a difference in bone mineral density among the three groups (p < .05). CONCLUSION: Local injection of a single dose of 200 microg of rhBMP-7 did enhance bone density when compared with the control group, although not in a statistically significant way when analyzed by an x-ray bone densitometer. This study serves as a starting point for future studies in bone tissue engineering by guiding the strategic administration of rhBMPs and the use of new state-of-the-art technologies, such as micro CT scanning, to analyze in a more detailed way, the effects of rhBMP administration.

Absorptiometry, Photon↗
PubMed2006

Dual segmental distraction osteogenesis of the midface in a patient with Apert syndrome.

OBJECTIVE: To present orthodontic treatment combined with dual segmental distraction osteogenesis in a patient with Apert syndrome. PATIENT: A 15-year-old boy exhibited severe midfacial hypoplasia with retruded and hypoplastic maxilla and anterior open bite. The patient was treated with a rigid external distraction II system for distraction osteogenesis, a preadjusted edgewise appliance, and a modified maxillary protraction headgear. The concave profile with midfacial hypoplasia was improved. A tight occlusal relationship between maxillary and mandibular teeth was achieved. Postoperative treatment results have been stable for 1 year.

Acrocephalosyndactylia↗
PubMed2000

Paediatric sleep apnoea and treatment with distraction osteogenesis.

Paediatric obstructive sleep apnoea (OSA) associated with craniofacial anomalies frequently is refractory to traditional treatment modalities. Skeletal expansion using distraction osteogenesis to correct facial deformities has proven to be an excellent treatment modality for the resolution of OSA. This paper discusses the use of distraction osteogenesis from infancy through adolescence and will show objective improvement in not only facial norms but also in OSA indices.

Adolescent↗
PubMed2002

Bone consolidation is enhanced by rhBMP-2 in a rabbit model of distraction osteogenesis.

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is a differentiation factor which has been shown to induce bone formation and heal bony defects in a variety of animal models. A possible application of rhBMP-2 is to accelerate bone regeneration during distraction osteogenesis. which clinically is a long procedure, often involving significant complications. In this study we tested the ability of rhBMP-2 to accelerate the consolidation phase of distraction osteogenesis in a rabbit model of leg lengthening. Tibiae were lengthened 2 cm over a period of ten days. rhBMP-2 was administered at the end of the lengthening phase. Two modes of rhBMP-2 application were tested: surgical implantation of rhBMP-2/ACS (absorbable collagen sponge) into the regenerate (50 microl of 1.5 mg/ml rhBMP-2, total dose = 75 microg rhBMP-2), and percutaneous injection of rhBMP-2/buffer (0.1 ml of 0.75 mg/ml rhBMP-2. total dose = 75 microg rhBMP-2) into three sites within the regenerate. Also, there were three groups of control animals: (1) no surgical intervention, (2) surgical implantation of buffer/ACS and (3) percutaneous injection of buffer. Rabbits were sacrificed at 5, 14 and 28 days after the interventions. Radiographic evaluation indicated a significant increase in bony union of the distraction regenerate in the rhBMP-2 treated groups compared with the untreated groups at 5 and 14 days. At 28 days, formation of a cortex and reestablishment of the medullary canal was evident only in the rhBMP-2 treated groups. The bone mineral content (BMC) of the regenerate was significantly higher in the rhBMP-2 treated groups at 5 and 14 days. However, at 28 days, BMC of the regenerate was similar in all groups. The average volumetric density of the regenerate was significantly higher in the rhBMP-2 injection group at day 14. In Summary, both injection of rhBMP-2/buffer and implantation of rhBMP-2/ACS enhanced the consolidation stage of distraction osteogenesis in this rabbit model.

Animals↗
PubMed2004

Distraction osteogenesis for augmenting the deficient alveolar ridge in preparation for dental implant placement: a case report.

Distraction osteogenesis is a process in which new bone is created in a defect of the alveolar ridge by stretching existing bone. The process was originally developed by a Russian orthopedist, Gavriel Ilizarov, for the correction of long-bone deformities. It was later adapted to the maxillofacial skeleton and alveolar ridge. Distraction osteogenesis involves surgically creating a mobile bone segment to which a distraction device is attached. By controlled movement, the bone segment, along with the soft tissues overlying it, are transported into a new position. After a suitable healing period, the distraction device is removed and dental implants can be placed. A case report is presented describing the use of alveolar distraction to augment a vertically deficient alveolar ridge.

Adult↗
PubMed1998

Bone regeneration and fracture healing. Experience with distraction osteogenesis model.

The relation between physical forces and the processes of bone regeneration and healing remains incompletely understood. Gaps in understanding of these processes stem in part from models that produce inadequate amounts of new bone for study. Bone created through the use of distraction osteogenesis provides an attractive substrate for the study of mechanical forces and their effects on bone formation because this technique produces large volumes of new bone in a controlled fashion. The optimal mechanical environment in which bone formation occurs clinically has not been fully determined. In laboratory studies, however, the mechanical environment can be manipulated, and resultant changes in bone formation can be measured. To investigate how changes in strain environment influence patterns of bone formation, a bilateral New Zealand White rabbit model of bilateral distraction osteogensis was implemented. When a stiffener was applied to the external distractor, computation analyses predicted a sevenfold to eightfold decrease in all strain measures. These reductions in gap strains appeared to induce significant decreases in bone volume fraction and mean trabecular thickness. When osteotomies were created at a 30 degrees angle to the bony axis to generate more shear within the gap tissue, changes in the distribution of gap strains and resultant new bone architecture were observed. Specific correlations between changes in tissue level strains and the pattern of bone regeneration were seen in both experiments. These results provide direct in vivo evidence that pluripotential gap tissues are sensitive to their physical surroundings. Mechanisms responsible for this sensitivity might include vascularity, stem cell supply, and scaffolding architecture. The process of bone formation in distraction osteogenesis appears to be related to bone formation processes associated with more common conditions. The distraction osteogenesis model described suggests a mechanism for bone formation that seems applicable to other more common processes associated with bone formation, including fracture healing and impaired fracture healing.

Adult↗
PubMed2005

Internal distraction osteogenesis with a unidirectional device for reconstruction of mandibular segmental defects.

PURPOSE: To present the authors' clinical experience with unidirectional internal distraction devices to reconstruct mandibular defects. PATIENTS AND METHODS: Five patients have been treated with mandibular distraction osteogenesis to reconstruct different acquired segmental defects. These mandibular defects (35 to 80 mm in length) were reconstructed by means of internal distraction devices with a transcutaneous activator. All the patients underwent complete resection of the affected bone and immediate placement of the distraction device on the remaining mandible. RESULTS: The results' analysis was based on clinical observation, postoperative radiographs, histopathologic findings and 3-dimensional computed tomographic scans. Successful distraction osteogenesis was achieved in 3 cases. In 1 case, extensive intraoral exposure of the device was observed, resulting in a failure of the procedure. One patient died of distant metastases 4 months after the resective surgery. CONCLUSION: Because of the limited number of cases, this study is preliminary. However, considering the good experimental and clinical results, this new technique offers an alternative for patients with segmental mandibular defects in which, because of local or general reasons, a more aggressive procedure should be avoided.

Aged↗
PubMed2006

Microscopic changes in the condyle and disc in response to distraction osteogenesis of the minipig mandible.

PURPOSE: Unilateral mandibular distraction osteogenesis (DO) has been shown to cause gross changes in the mandibular condyle and articular disc. The purpose of this study was to correlate histologic findings with these gross changes in a minipig distraction model. MATERIALS AND METHODS: Semiburied distractors were placed via submandibular incisions in 15 minipigs. Two unoperated animals served as controls. The protocol consisted of 0-day latency and rates of 1, 2, or 4 mm/day for a 12-mm gap. After the minipigs were killed (at 0, 24, or 90 days), ipsilateral and contralateral condyles and discs were harvested, decalcified, prepared for standard paraffin embedding, and evaluated to determine changes in 1) morphology and thickness of the articular cartilage and subchondral bone and 2) morphology of the disc. RESULTS: In control animals, there were no degenerative changes in the articular cartilage and underlying condylar bone; there were no significant differences in the mean articular cartilage thickness. The temporomandibular joint discs were normal. In experimental animals, distracted condyles showed increasing degenerative changes and mean articular cartilage thickness as the DO rate increased. The discs were thinner. These changes were present, but to a lesser degree, in the contralateral condyles. After 90 days, degenerative changes in the condyles and discs were reduced, after remodeling, except in the 4 mm/day DO group. CONCLUSIONS: Histologic changes in the condyles and temporomandibular joint discs in response to mandibular DO correlated with previously reported gross changes. These changes were greater at higher distraction rates and remodeling back to normal occurred in mandibular condyles distracted at 1 mm/day.

Animals↗