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Modified Ilizarov technique for infected nonunion of the femur: the principle of distraction-compression osteogenesis.

PURPOSE: To evaluate the treatment outcome of the modified Ilizarov technique in infected nonunion of the femur. METHODS: Between 1989 and 2002, records of 20 patients with infected nonunion of the femur treated with the modified Ilizarov technique were retrospectively reviewed. The modified Ilizarov frame was fixed after necrectomy of the dead infected bone and tissues. A proximal or distal corticotomy was performed following biological principles. For regeneration of gap, segmental transport was performed in 11 patients with a gap of more than 5 cm; acute docking followed by lengthening at the corticotomy site was performed in 9 patients with a gap of smaller than 5 cm. Mobilisation was started early with active participation of the physical therapist and the patients. Bone and functional results were measured and complications were categorised according to the Association for the Study and Application of the Method of Ilizarov guidelines. RESULTS: The mean follow-up period was 62.8 months. Bony union and eradication of the infection was achieved in all patients except one who underwent amputation due to uncontrolled infection. Bone results were excellent in 13 patients, good in 4, fair in one, poor in one, and treatment failure (amputation) in one. Functional results were excellent in 3 patients, good in 9, fair in 3, poor in 4, and failure in one. A total of 71 complications occurred: 35 problems, 6 obstacles, and 30 true complications. The mean healing index was 38.3 day/cm (standard deviation, 1.6 day/cm). CONCLUSION: The Ilizarov technique is a good salvage operation for infected nonunion of the femur. Limb salvage is preferable to prosthesis if the limb is viable, adequately innervated and the patient is mentally and financially committed to save the limb.

Adolescent↗

Reliability of distraction vector transfer in unilateral vertical distraction of the mandibular ramus.

Mandibular distraction osteogenesis fails in correcting the skeletal deformities if the vector of distraction is incorrect. Lack of vector control is caused mainly by two factors: first, deficient vector planning and transfer, and, second, resistance of the masticatory muscles and the remaining soft tissue envelope toward elongation. To enhance predictable placement of intraoral distraction devices during surgery and thereby the treatment outcome, a method combining planning, simulation, and transfer was developed. The presurgical planning was based on frontal and lateral head films, and the planned position and orientation of the distraction device was applied on the stereolithographic model. This model was cut according to the planned osteotomy, and the distraction was simulated. The transfer procedure copied the planned and simulated position of the distraction device during surgery by use of an individual guiding splint. The guiding splint was fabricated on plaster models, and transferred to the stereolithographic model to reproduce the planned and simulated distraction treatment during surgery. The reliability of the vector-transfer method was evaluated cephalometrically in a homogenous group of 13 patients and their respective stereolithographic models in comparison with the planned, simulated, and transferred distraction vectors.

Adolescent↗

Greater frequency of distraction accelerates bone formation in open-wedge proximal tibial osteotomy with hemicallotasis.

BACKGROUND: In chickens, increased distraction frequency stimulates bone formation in distraction osteogenesis. PATIENTS AND METHODS: We investigated the effect of two different distraction frequencies on bone formation in the distracted portion, and on the time of removal of the fixator, in open-wedge osteotomies of the proximal tibia with hemicallotasis (HCO). The study included 20 consecutive patients (20 knees) who underwent HCO for medial osteoarthrosis of the knee. 10 knees were distracted at a rate of 0.25 mm four times a day (the 4-step group); and the other 10 knees were distracted at a rate of 0.125 mm eight times a day (the 8-step group). RESULTS: There were no significant differences in the preoperative FTAs or the correction angles between the two groups. At all intervals until 6 weeks after the completion of distraction, bone mineral density in the distraction gap was significantly higher in the 8-step group than in the 4-step group. The average time in external fixation was 78 (SD 5) days in the 8-step group as compared to 89 (SD 6) days in the 4-step group, a significantly shorter time. INTERPRETATION: Our findings indicate that an increase in the distraction frequency in HCO provides better bone formation, resulting in a shorter external fixation period.

Aged↗

Novel approach to calvarial bone transport using a rabbit model.

Calvarial defects sometimes require cranioplasty to protect the brain. Alloplastic materials, such as acrylic resin, hydroxyapatite ceramics, and titanium, involve various problems, such as vulnerability, infection, deformity resulting from growth, and high cost. We devised a new bone transport model in the rabbit based on the distraction osteogenesis theory of Ilizarov. Twelve Japan white rabbits with a mean body weight of 2.5 kg aged 12 weeks were used. Craniectomy (7 x 14 mm) was performed in 12 rabbits. Trapezoid bone osteotomy was performed anterior to the calvarial defect in 10 rabbits. The distraction device (Extension-plates) was fixed between the trapezoid bone island and the skull. Distraction was initiated 5 days postoperatively. The device was activated once every other day, with approximately 0.75 mm or 0.5 mm per activation. Bone distraction was continued until the rod could not be moved. The lengths of distraction were 4 mm in two cases, 5 mm in one case, 6 mm in one case, and 7 mm in two cases, with a mean of 5.5 +/- 0.56 mm. Both radiographic and histological findings showed osteogenesis by intramembranous ossification and trans-chondroid bone formation. Distraction osteogenesis has potential clinical applications in cranioplasty, especially in children because usage of autogenous bone is difficult if not impossible in most cases.

Animals↗

Transverse Tibial Transport for Limb Salvage in Ischemic Lower Extremity Disease: Technique, Mechanisms, and Clinical Outcomes-A Systematic Review.

Transverse tibial transport (TTT) is a surgical technique derived from Ilizarov's distraction osteogenesis principles that stimulates angiogenesis and microcirculatory regeneration in the ischemic lower limb without directly manipulating macrovascular anatomy. By creating a proximal tibial cortical bone window and distracting it transversely using an external fixator, TTT triggers converging cascades of growth factor release, endothelial progenitor cell mobilization, and immunomodulation that translate into improved distal limb perfusion and wound healing. Combined TTT plus endovascular therapy improves amputation-free survival versus endovascular therapy alone. Prospective randomized trials and standardized international protocols are needed to consolidate TTT's role in multidisciplinary limb salvage pathways.

Humans↗

Tooth-borne distraction to widen the mandible. Technical note.

Based on reported animal studies, the case report presented demonstrates the use of tooth-borne distraction osteogenesis for mandibular widening of 1 cm in order to avoid extraoral distraction devices. Detrimental side effects on healthy anchoring teeth are not likely.

Adult↗

Advantage of three-dimensional models in intraoral callus distraction.

Distraction osteogenesis has become an important method of reconstructing hypoplastic facial bones. Intraoral callus distraction is a great aesthetic improvement, because no visible scars are caused. Precise preoperative planning is necessary, however, because the direction of distraction cannot be influenced postoperatively. Nine three-dimensional (3-D) models were used in three intraoral distraction cases: two patients suffered from unilateral hemifacial microsomia and one from micrognathia after bilateral ankylosis caused by multifocal osteomyelitis in childhood. In each case, models of the head were produced and the distraction was simulated preoperatively. The amount of distraction was 18 mm in the two hemifacial microsomia patients and 18 and 14 mm in the ankylosis case. Extension of distraction in the ankylosis patient was shorter on one side in order to achieve a correct midline position. A slight overcorrection of 3-5 mm was allowed to cover relapse and unpredictable future growth deficiency. Three-dimensional models can supply important information when employed in intraoral callus distraction. They allow anticipation of pitfalls and help to achieve a foreseeable result. Further advantages may be expected with complete 3-D enoral distraction in the future.

Child↗

Effect of recombinant human bone morphogenetic protein-2 on mandibular distraction at different rates in an experimental model.

This study evaluates the effect of recombinant human (rh) bone morphogenetic protein (BMP)-2 on mandibular distraction at normal and rapid distraction rates. This study also determines the feasibility of compensating for the increased distraction rate by the addition of rhBMP-2 while maintaining the quality of the distraction regenerate. Twenty-four New Zealand white rabbits were divided into 2 groups, 1 treated at a normal distraction rate (0.9 mm/d) and the other at a rapid distraction rate (2.7 mm/d). At the end of the active distraction period, rhBMP-2 was injected into distraction regenerate, and the contralateral side was used as a control. The distraction regenerates were analyzed by plain radiography, microcomputed tomography, and mechanical testing. The results showed that rhBMP-2 can promote bone formation at both rapid and normal distraction rates. At week 2 and week 4 of consolidation, bone volumes in the BMP-injection sides were significantly higher than in the control sides, but no statistically significant difference was observed between the BMP-injection sides of the rapid and normal distraction groups. At week 8 of consolidation, mechanical testing demonstrated no significant difference of the failure load and stiffness between the BMP-injection and control sides. In conclusion, the study indicates that rhBMP-2 can enhance bone ossification at both normal and rapid distraction rates. The addition of rhBMP-2 can compensate for the rapid distraction rate in mandibular distraction osteogenesis. However, in the long term, the bone quality and stiffness of the distraction regeneration was not influenced by rhBMP-2.

Animals↗

Experimental study of mechanical analysis in mandibular lengthening. Application of strain gauge measurement.

In distraction osteogenesis, the assessment of new bone formation and the decision of when to remove the distraction device are very important from clinical viewpoint. The purpose of this study was to measure bone stiffness using a strain gauge during and after mandibular lengthening, and to compare the results with those from radiographic and histological examinations. Twelve adult mongrel dogs served as the experimental subjects. An external distraction device was connected to the mandible, and distraction was started 7 days after operation and continued for 10 consecutive days. The animals underwent strain gauge measurement and radiographic examination of the mandible at the completion of distraction and every 2 weeks until the end of the consolidation period. The animals were then sacrificed at 2, 4, 6, 8, 10, and 12 weeks after completion of the distraction for histologic examinations. There was correlation between the amount of decrease in strain, increase in ratio of radiopacity, and newly formed bone in the distracted area.

Animals↗

[Le Fort III osteotomy and medium position distraction for mid-facial hypoplasia].

OBJECTIVE: To probe the possibility of distraction osteogenesis for correction of mid-facial hypplasia using a new technique. METHODS: The distraction system of mid-facial skeleton consisted of a face-bow, the elastic loops and a device that hitched to bone holes made in the aperture rim. Flllowing Le Fort III osteotomy, a bone hole was drilled at each side of the external-inferior rim of the aperture by a dental bur. The traction device was hitched to the holes through the nostrils. Distraction began three days postoperatively, with the force adjusted dependently upon the rate of progress. When the skeleton reached to the planed position, distraction was retained with a minor force for 8 weeks. Three adults with mid-facial hypoplasia underwent this treatment. RESULTS: The mid-facial skeleton showed a balanced advancement. The patients' facial contour and occlusal relationship recovered completely. CONCLUSIONS: Patients with severe mid-facial hypoplasia could be corrected ideally by the new technique, with balanced advancement of mid-facial skeleton, minor trauma. The design of distraction system was reasonable. The manipulation of the procedure was easy.

Adult↗

[A postoperative osteosarcoma recurrence after bone distraction by Ilizarov method in a dog].

Distraction osteogenesis by Ilizarov's method is becoming popular for limb saving surgery today. In this article we report a case of osteosarcoma recurrence after using bone distraction in a dog with osteogenic sarcoma. This case suggests that stimulation of osteogenesis by bone distraction promotes tumor recurrence and metastases in osteosarcoma. We recommend to use this method only when allograft or endoprostheses can not save the limb after wide bone resection.

Animals↗

Stoppers in RED II distraction device: is it possible to prevent pin migration?

Distraction osteogenesis has become popular for the treatment of hypoplastic congenital craniomaxillofacial anomalies. Rigid external distraction (RED II) after Le Fort III osteotomy was shown to be a highly effective treatment for the management of midface hypoplasia. This device is used with a halo vest, which is placed at the cranial equator. Intracranial penetration of the fixation pins of the halo is one of the complications of an external distraction device. To prevent pin penetration in rigid external distraction, the authors designed polylactic acid/polyglycolic acid (PLA/PGA) plates that were circular; the plates were 0.8 cm in diameter and had 1.5-mm holes in the center, through which the tip of the pins would pass. To quantify the applied torque by manual tightening of the screws of the distraction device and to measure intraosseous cone depth created by the penetration of the conical part of the screws with and without the PLA/PGA composite stopper, first an in vitro experiment was undertaken on cadaver. Then these PLA/PGA plaques, or stoppers, were placed over the bone surfaces of the cranium of the patients where the tip of the pins press. PLA/PGA stoppers are malleable and adapt their shape to the interactive forces between bone and the pins. They act as a second barrier, and spread the pressure of the screws to larger surfaces, thus securing better stabilization. The penetration of wider portions of the screw into scalp is reduced, minimizing the scalp damage caused by the screws. Biodegradable and biocompatible PLA/PGA stoppers avoid intracranial migration of the fixation pins, especially in children.

Adolescent↗

[Initial experiences with a new distraction implant system for alveolar ridge augmentation].

The masticatory rehabilitation of patients is dependent on the quality and volume of residual jaw bone. Loss of volume caused by tumor-related mandibular ridge resection or age-related atrophies may cause considerable problems. Reconstructive methods using free iliac bone, external tabula, or sandwich plasties are only a few examples of the common surgical treatment modalities. Doing without bone grafts, alveolar ridge augmentation by means of distraction osteogenesis might become a value method to improve the denture-bearing area. A new distraction implant system is shown and its first clinical use reported. Two distraction implants were inserted after an anterior segmental osteotomy. The alveolar ridge was then elevated 1 mm each day until the required augmentation of about 8 mm was achieved. After a latency period for pre-ossification of the callus, the distraction implants were replaced by the endosseous implants. The implant system and the surgical technique are shown, and the results are discussed. We believe that the implant distraction procedure will make useful contribution to the management of masticatory rehabilitation.

Alveolar Bone Loss↗

Micro-computed tomography evaluation of the glenoid fossa and mandibular condyle bone after bilateral vertical ramus mandibular distraction in a canine model.

The aim of this study was to quantify bone microarchitecture within the glenoid fossa and mandibular condyle following mandibular distraction osteogenesis. Eight 6- to 9-month-old male beagle dogs underwent bilateral vertical mandibular distraction with semiburied distractors (12 days of distraction at 1 mm per day). One unoperated animal served as control. After distraction the animals were divided into two groups (N = 4) and killed after 1 or 2 months of consolidation. Three-dimensional trabecular architecture was analyzed by micro-computed tomography (microCT). At both sites the overall trends were similar. In the glenoid fossa, there was decreased bone volume, trabecular number, and connectivity density and increased trabecular separation at 1 month and decreased trabecular thickness and increased structure model index compared with the control (P < 0.05). In the mandibular condyle, there was decreased bone volume, trabecular number, and connectivity density at both 1 and 2 months, with decreased trabecular thickness and increased structure model index at 2 months only compared with the control (P < 0.05). The bone became less dense and more rodlike. These bone changes are similar to those seen by the effects of aging or impaired normal function. Thus, in the short term, changes occur in the bone microstructure of the glenoid fossa and mandibular condyle after vertical mandibular ramus distraction in the canine model.

Animals↗

Micro-computed tomography evaluation of the glenoid fossa and mandibular condyle bone after bilateral vertical ramus mandibular distraction in a canine model.

The aim of this study was to quantify bone microarchitecture within the glenoid fossa and mandibular condyle following mandibular distraction osteogenesis. Eight 6- to 9-month-old male beagle dogs underwent bilateral vertical mandibular distraction with semiburied distractors (12 days of distraction at 1 mm per day). One unoperated animal served as control. After distraction the animals were divided into two groups (N = 4) and killed after 1 or 2 months of consolidation. Three-dimensional trabecular architecture was analyzed by micro-computed tomography (muCT). At both sites the overall trends were similar. In the glenoid fossa, there was decreased bone volume, trabecular number, and connectivity density and increased trabecular separation at 1 month and decreased trabecular thickness and increased structure model index compared with the control (P < 0.05). In the mandibular condyle, there was decreased bone volume, trabecular number, and connectivity density at both 1 and 2 months, with decreased trabecular thickness and increased structure model index at 2 months only compared with the control (P < 0.05). The bone became less dense and more rodlike. These bone changes are similar to those seen by the effects of aging or impaired normal function. Thus, in the short term, changes occur in the bone microstructure of the glenoid fossa and mandibular condyle after vertical mandibular ramus distraction in the canine model.

Animals↗

Continuous and intermittent bone distraction using a microhydraulic cylinder: an experimental study in minipigs.

Distraction osteogenesis of the mandible is an option in the treatment of mandibular hypoplasia. Today, only intermittent distraction devices are available for clinical application. The aim of this study in minipigs was to evaluate continuous bone distraction using a microhydraulic cylinder. After a seven-day interval, continuous or intermittent distraction of 1.5 mm/day was established for 10 days. Immediately after active distraction, two animals and 20 days later the other four animals were killed and radiographs taken. The mandible was then removed en bloc and the distracted bone examined histologically. Intermittent distraction forces of up to 2500 kPa were necessary to move the cylinders' piston. The pressure needed for continuous distraction was considerably lower (1200-1300 kPa). While the specific histological structure of the varying zones in the distraction gap was similar after continuous and intermittent distraction, bone healing was accelerated after continuous distraction as shown by ultrasonography and scanning electron microscopy.

Animals↗

Effect of nerve growth factor and Schwann cells on axon regeneration of distracted inferior alveolar nerve following mandibular lengthening.

OBJECTIVE: To study the effect of nerve growth factor (NGF) and Schwann cells on axon regeneration of the inferior alveolar nerve following mandibular lengthening with distraction osteogenesis. METHODS: Unilateral mandibular osteodistraction was performed in 9 healthy adult male goats with a distraction rate of 1 mm/d. Every 3 goats were killed on days 7, 14 and 28 after mandibular lengthening, respectively. The inferior alveolar nerves in the distraction callus were harvested and processed for ultrastructural and NGF immunohistochemical study. The inferior alveolar nerves from the contralateral side were used as controls. RESULTS: On day 7 after distraction, axon degeneration and Schwann cell proliferation were observed, and very strong staining of NGF in the distracted nerve was detected. On day 14 after distraction, axon regeneration and remyelination were easily observed, and NGF expression started to decline. On day 28 after distraction, the gray scale of NGF immunoreactivity recovered to the normal value and the Schwann cells almost recovered to their normal state. CONCLUSIONS: Gradual mandibular osteodistraction can result in mild or moderate axon degeneration of the inferior alveolar nerve. Nerve trauma may stimulate the proliferation of Schwann cells and promote the synthesis and secretion of NGF in the Schwann cells. Schwann cells and NGF might play important roles in axon regeneration of the injured inferior alveolar nerve following mandibular lengthening.

Animals↗

Influence of distraction rates on the temporomandibular joint position and cartilage morphology in a rabbit model of mandibular lengthening.

PURPOSE: Although various aspects of bone formation during distraction osteogenesis have been studied extensively, there are only limited experimental data concerning the influence of mandibular distraction rates on structural alterations in the temporomandibular joint (TMJ). In this study, a rabbit model of unilateral mandibular distraction was used to test the effects of various strain schedules on the position and morphology of the TMJ. MATERIAL AND METHODS: Fifty-two immature white female rabbits were used. The distraction procedure was performed using physiologic (2,000 microstrains, 1 per day) and elevated strain magnitudes (20,000 microstrains, 1 per day), as well as high strain magnitudes (200,000 and 300,000 microstrains, 1 per day). The investigation of the TMJ included clinical, radiologic, and histologic aspects. RESULTS: Clinical and radiologic examinations at the end of the distraction period showed no evidence of joint luxation even at maximal distraction rates. Histologic and ultrastructural analyses revealed a positive correlation between the degree of mechanical loading and the development of degenerative alterations in the cartilage. In samples distracted at hyperphysiologic strain magnitudes, all cartilaginous layers were reduced in the regions of the TMJ that had been exposed to the higher pressure forces. The fibrous layer became nearly completely destroyed. CONCLUSIONS: These experimental data show that distraction schedules with single but hyperphysiologic loads may lead to degenerative or even early arthrotic changes in the condyle. These data support the principle that distraction protocols should be performed without extensive mechanical loading on the TMJ.

Animals↗