Use of a plate-guided distraction device for transport distraction osteogenesis of the mandible

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Use of a plate-guided distraction device for transport distraction osteogenesis of the mandible
April 2004
Alan S. Herford, DDS, MD**
Journal of Oral and Maxillofacial Surgery Online
Abstract
Background Transport distraction osteogenesis has been used to reconstruct continuity defects by regenerating bone and soft tissues. A challenge has been to maintain the correct vector during the distraction process. A new type of distraction device was recently developed that uses a standard reconstruction plate to ǃ?guideǃ? the transported segment of the bone. This plate-guided distractor device (PGD) intimately follows the shape of the plate, thus allowing for 3-dimensional vector control during the distraction process.
Patients and methods Four patients underwent transport distraction osteogenesis for reconstruction of segmental mandibular defects ranging in size from 4 to 7 cm. The age of the patients ranged from 27 to 62 years. Two patients had been treated with radiotherapy as part of treatment for oral malignancy. A standard locking reconstruction plate was placed to bridge the continuity gap. An osteotomy was performed to create a bone transport segment. The PGD was secured to both the reconstruction plate and the transport bone. After a latency period of 7 days, the device was activated at a rate of 1 mm/d. The distraction process continued until the transport segment reached the opposing bone or sufficient bone and soft tissue were reconstructed for oral rehabilitation.
Results All patients achieved hard and soft tissue formation. Two patients had premature consolidation of the distraction regenerate but had sufficient tissue for rehabilitation.
Conclusion A PGD can be used to regenerate missing hard and soft tissues. An advantage of this technique is that it uses a reconstruction plate that is routinely placed to bridge mandibular continuity defects. This device allows for ultimate vector control by intimately following a carefully adapted plate.
Mandibular defects can range from isolated segmental defects to large extensive areas of bone loss involving the entire jaw. These defects are often congenital, a result of trauma, infection, or resection of benign and malignant tumors. Many options are available for mandibular reconstruction, including reconstruction plates, particulate bone grafts, block bone grafts, and microvascular free tissue transfer such as a composite fibular graft.
Distraction osteogenesis is another option that has proved to be a reliable method for reconstructing missing segments of bone.1ǃÏ15 Because most mandibular defects are composite defects, transport distraction osteogenesis often is an excellent treatment option because both hard and soft tissues are reconstructed.16ǃÏ29 Originally used for lengthening long bones, this process has gradually been adapted to the maxillofacial region.30ǃÏ40
Distraction osteogenesis in the maxillofacial region has evolved and continues to do so. This evolution has proceeded from bulky external appliances to smaller devices. To eliminate the nonaesthetic scarring caused from the pin ǃ?drag,ǃ? smaller internal devices have been developed. In 1996, McCarthy5 stated that the next 2 goals to be achieved are ǃ?1) the ability to make vector changes during the period of distraction, ie, ǃÚinterceptive multidimensional distraction;ǃ٠and 2) the development of an internal or intraoral device to avoid scarring.ǃ?
A new type of distractor (KLS Martin, Jacksonville, FL) is available for reconstructing segmental mandibular defects that meets both of these objectives. The plate-guided distraction device (PGD) uses a reconstruction plate that is routinely placed to bridge the mandibular continuity defect.41 This plate can be contoured before resection and then reapplied to reconstruct the mandible. The PGD then intimately follows the shape of the plate during distraction. This allows for 3-dimensional vector control during the distraction process. The distractor is an internal device and may obviate the need for microvascular free tissue transfer or large bone grafts in some cases (Figs 1A, B).
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