Long backbone bone defects are common clinical disorders, of which critical bone defects are one of the modern bone and clinical problems often encountered but difficult to be properly solved. In recent years, with the in-depth research on bone tissue engineering, the repair effect of approximating autologous bone has been achieved, and it has been recognized as one of the most promising strategies for repairing bone defects. Long stem bone defect models are also increasingly used for the observation of the effect of tissue engineered bone repair of bone defects. For the definition of critical bone defect, it mainly refers to the bone defect of the smallest size of bone non-healing caused under the condition of intervention without applying any external factors. Clinical animal models of long bone stem bone defects are used to test the osteogenic activity of bone graft materials. Currently, there are three main methods used for animal models of long bone stem bone defects: bone defects without immobilization, bone defects requiring immobilization, and bone defects with micromotor immobilization.
Principle
The basic principle of [Animal model of long bone stem bone defect]: The mechanism of long bone stem bone defect is very complicated, and direct violence and bone infection are the common causes of bone defect. In the experiment, the bone defect is often caused directly on the long bone stem by wire saw or sharp bone chisel according to the need, and the periosteum can be removed together with the bone if necessary. Since the size of the rabbit ulna and radius are basically the same, a 1.5 cm defect in the radius or ulna alone will not cause mechanical instability, but some studies have shown that 1.5 cm is the critical value for radius defects in rabbits, and a 1.5 cm defect will directly lead to non-healing of the bone.
Operation method
Animal model of long bone stem bone defect
Principle
The basic principle of [Animal model of long bone stem bone defect]: The mechanism of long bone stem bone defect is very complicated, and direct violence and bone infection are the common causes of bone defect. In the experiment, the bone defect is often caused directly on the long bone stem by wire saw or sharp bone chisel according to the need, and the periosteum can be removed together with the bone if necessary. Since the size of the rabbit ulna and radius are basically the same, a 1.5 cm defect in the radius or ulna alone will not cause mechanical instability, but some studies have shown that 1.5 cm is the critical value for radius defects in rabbits, and a 1.5 cm defect will directly lead to non-healing of the bone.
Materials and Instruments
Equipment: adult healthy rabbits, adult green goats, dogs, etc., dental table saw, interlocking intramedullary nails with micromotion Move The experimental procedure of the animal model of bone defects in the long backbone is basically as follows: . The radius is used to make a model of the bone defects, and because the affected limb is supported by the ulna bone, the area of the defect will not be shortened or disappeared due to limb shortening, and it will be able to exist continuously during the experimental observation process For more product details, please visit Aladdin Scientific website.
B. The radius is accurately resected by a dental table saw at the distal end of the anterior pronator teres muscle stopping point by 1.5 cm.
C
A. Commonly used animals are goats, dogs, rabbits, etc., and the femur or tibia of the hind limb is usually selected.
B. In order to maintain the normal alignment of the bone tissues, it is necessary to provide strong internal and external fixation during the operation. The osteotomy position is usually selected at the mid-portion of the bone tissue, and the size of the defect can be adjusted according to the purpose of modeling.
3 . Bone defect micromotor fixation model
A. Adult green goats are used, and the femur is exposed under anesthesia.
B. An interlocking intramedullary nail, which can produce micromotor movements within 2 mm, is used to fix a 2 cm defect in the mid-portion of the femur created by an amphitheatrical osteotomy.
C. The corresponding stress stimulation of the defect graft can be produced by the contraction of muscles of the goat or by walking. C. Corresponding stress stimulation of the bone defect graft can be produced by contraction of the goat muscle or by walking.