الفهرس 
Distraction OsteogenesisOnly 14 pages are availabe for public view
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Abstract
Limb salvage surgery is a very new technique and became very popular since the 1970’s and 1980’s and this is contributed to the advances in several fields, including imaging techniques, chemotherapy, and radiotherapy. Through these advances, as well as the advances in soft tissue reconstruction, patients with primary malignant bone tumours gained a chance for sparing their limbs from amputation.
Successful limb salvage depends on early diagnosis by the physician, a sequence of different imaging studies, including CTs, MRIs and bone scans, and quick referral to a specialist.
External fixation has evolved from being used primarily as a last resort fixation method to becoming a main stream technique used to treat a myriad of bone and soft tissue pathologies. Techniques in limb reconstruction continue to advance largely as a result of the use of these external devices. A thorough understanding of the biomechanical principles of external fixation is useful for all orthopedic surgeons as most will have to occasionally mount a fixator throughout their career.
One of the new methods for limb salvage and reconstruction is Distraction Osteogenesis. Distraction Osteogenesis is a biologic process of new bone formation between the surfaces of bone segments that are gradually separated by incremental traction. Specifically, this process is initiated when distraction forces are applied to the callus tissues that connect the divided bone segments, and continues as long as these tissues are stretched. The traction generates tension that stimulates new bone formation parallel to the vector of distraction.
The principles of external fixation are clinically appealing as they: provide low-risk stable fixation of fractures or joints, are adjustable, allowing translation, rotation, angulation, and axial adjustments, provide access to the extremity for wound care and reconstructive surgery. The Ilizarov-type of circular external fixator, which is less stable to axial loading than are most cantilever systems but relatively resistant to torsion, provides an excellent biomechanical environment for bone formation. The disadvantages of the traditional circular external fixator are its bulky size, the fact that it is difficult to apply and adjust, and that it requires multiple sites for transfixing wires.
Chemotherapy and radiotherapy and important factors in the treatment plan. Prior to the introduction of chemotherapy in the 1970s, prognosis of primary malignant bone tumours was dismal. Efficient chemotherapy has made long-term survival possible after excision of malignant limb tumours, and has helped to reduce the margin of surgical excision.
Distraction osteogenesis is beneficial for patients with a good long-term prognosis and for growing children. For patients with metastatic disease, prosthetic replacement after resection of the tumour will provide an early improvement in function and is indicated. Other techniques offer simpler and less time-consuming reconstruction for some bony defects, but distraction osteogenesis has a place in reconstruction after the excision of a tumour; it will become more attractive if the duration of the treatment can be shortened.