A Mathematical Model for Mandibular Distraction Osteogenesis

Sa, Schendel; Jh, Heegaard

doi:10.1097/00001665-199611000-00013

Cited by 6 publications

(2 citation statements)

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“…doi: 10.101 6/j.orthres.2004.09.010 models [6,7,19], stereolithographic models [5], and threedimensional physical models [20]. Mathematical models of mandibular DO have also been developed in attempts to determine the optimum distraction rate [21] and distraction vector [22] for the procedure. While all of these approaches are of interest in pre-operative planning, none of them can address the local tissue-level stresses and strains experienced by the multipotent mesenchymal tissue within the distraction gap, information that needs to be obtained in order to elucidate the local stresses and strains that lead to the highest amount of bone regeneration.…”

Section: Introductionmentioning

confidence: 99%

Mechanobiology of mandibular distraction osteogenesis: Finite element analyses with a rat model

et al. 2005

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Three-dimensional finite element (FE) analyses were performed to characterize the local mechanical environment created within the tissue regenerate during mandibular distraction osteogenesis (DO) in a rat model. Finite element models were created from three-dimensional computed tomography image data of rat hemi-mandibles at four different time points during an optimal distraction osteogenesis protocol (i.e., most successful protocol for bone formation): end latency (post-operative day (POD) 5), distraction day 2 (POD 7), distraction day 5 (POD lo), and distraction day 8 (POD 13). A 0.25 mm distraction was simulated and the resulting hydrostatic stresses and maximum principal tensile strains were determined within the tissue regenerate. When compared to previous histological findings, finite element analyses showed that tensile strains up to 13% corresponded to regions of new bone formation and regions of periosteal hydrostatic pressure with magnitudes less than 17 kPa corresponded to locations of cartilage formation. Tensile strains within the center of the gap were much higher, leading us to conclude that tissue damage would occur there if the tissue was not compliant enough to withstand such high strains, and that this damage would trigger formation of new mesenchymal tissue. These data were consistent with histological evidence showing mesenchymal tissue present in the center of the gap throughout distraction. Finite element analyses performed at different time points during distraction were instrumental in determining the changes in hydrostatic stress and tensile strain fields throughout distraction, providing a mechanical environment rationale for the different levels of bone formation in end latency, and distraction day 2, 5, and 8 specimens.

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Section: Introductionmentioning

confidence: 99%

Mechanobiology of mandibular distraction osteogenesis: Finite element analyses with a rat model

et al. 2005

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“…They indicated that this approach permitted better prediction of results. 12 In 1997, Roth used 3-D tomography to quantitatively define volume changes in pre-and postoperative cases of mandible distraction. They also performed mandible panoramic radiographic studies to judge symmetry.…”

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confidence: 99%

Mandible Distraction Using Internal Device

Freitas

Alonso²,

Busato³

et al. 2007

Journal of Craniofacial Surgery

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For many years, surgeons have sought a method to treat severe facial deformities without using bone grafts and extensive surgery. Distraction osteogenesis offers this promise. The technique used in mandibular hypoplasia follows the basic principles proposed by Ilizarov which states that the device must be elongated 1 mm per day to create optimal bone production. Despite the widespread implementation of this recommendation to include the 1-mm/day separation, doubt still exists as to whether this is the optimal treatment regimen. Intraoral devices with percutaneous activator pins were used in 16 patients with hypoplastic mandibles. The results of distraction were documented by panorex and cephalogram of the mandible. The length of the ramus as well as multiple mandible dimensions and facial angles were measured. The panorex and cephalogram of the mandible were effective in demonstrating the significant increase in length of the mandible and ramus, as well as the entire mandible, but there was no correlation between the stretching obtained by the distraction device and that measured by the radiographic studies. The S-N-B angle was the only facial angle in which there is a statistically significant increase measured and this appeared to be related to a mandible rotation. It is concluded that the mandible distraction (using an intraoral device and an external activator pin) was effective in increasing the ramus length and both the panorex and the cephalogram were effective in demonstrating this morphologic change. There was no correlation between the clinical result and the radiographic studies demonstrating that the clinical judgment still has a significant role in controlling mandible distraction.

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