动物造模,颌骨缺损 z-bo 2021-10-21 459

　　The mandible defect model of mini-pig was established by surgical operation.

　　1. Experimental method 10 Chinese experimental miniature pigs aged 18 months, female. Miniature pigs are under conventional anesthesia, and the premolars and first molars of the right mandible are extracted. Two months later, the animals are randomly divided into segmental resection of the mandible to preserve the periosteum group and segmental resection of the mandible without preservation of the periosteum group, of which the periosteum group is preserved 6 heads, 4 heads without periosteal cluster. The preserved periosteal group was divided into 40mm, 50mm and 60mm groups according to the different length of bone block removal, and the non-retained periosteum group was divided into 10mm and 20mm groups according to the different length of bone block removal, with 2 animals in each group. Under general anesthesia, make an incision parallel to the lower edge of the right mandible of the mini-pig, about 10 cm long and reaching the bone surface. Without preserving the periosteum group to separate sharply on the periosteum, leaving the periosteum group to cut the periosteum sharply along the lower edge of the mandible, gently lift the mandibular buccal tongue and alveolar periosteum with a periosteal dissector, and remove the appropriate size of bone as needed Block, use reconstruction titanium plate plus double cortical titanium nail for firm internal fixation. X-rays were taken at 4 weeks, 8 weeks, and 12 weeks after the operation with and without preservation of the periosteum group. The position of the radiograph was selected as a mini-pig mandibular cross-bite film.

　　2. Experimental results

　　(1) 40mm group with preserving periosteum group

　　1) X-ray findings at 4 weeks postoperatively: the defect area has been connected by calcified new bone. Compared with the contralateral jaw, the density is slightly lower, and it does not reach the volume of the normal jaw. The center of the new bone is about 0.5mm wide and perpendicular to The slit-like translucent area of the buccal-lingual bone plate. The buccal titanium plate is well retained, and there is no density reduction area around all the bicortical fixation titanium nails. Uneven density of new bone masses can be seen on the buccal side of the titanium plate.

　　2) X-ray findings at 8 weeks postoperatively: the defect area has been replaced by calcified new bone, and its X-ray transmission is close to that of the jawbone, basically reaching the volume of the normal jawbone. The center of the new bone is perpendicular to the buccal-lingual bone plate The seam-like translucent area of the dog has been blurred, and a round bony process can be seen on the tongue side. The buccal titanium plate and titanium nails are well retained, and there is no density reduction area around all the bicortical fixed titanium nails. The new buccal bone mass on the buccal side of the titanium plate was denser and larger than that at 4 weeks and wrapped the reconstructed titanium plate.

　　3) X-ray findings at 12 weeks postoperatively: The defect area has been replaced by well-calcified new bone, and its X-ray transmission is the same as that of the contralateral jaw tissue, reaching the volume of the normal jaw. The center of the new bone is perpendicular to the cheek and tongue. The slit-like translucent area of the lateral bone plate has disappeared, and the rounded bony protrusion on the lingual side is significantly reduced. The buccal pure titanium reconstruction plate and the titanium nails are well retained, and there is no density reduction area around all the double cortical fixation titanium nails. The buccal new bone mass of the titanium plate has no obvious change compared with 8 weeks.

　　(2) Periosteum group 50mm group: The X-ray findings at each stage are similar to those of the 40mm group periosteum group.

　　(3) 60mm group with preserving periosteum group

　　1) X-ray findings at 4 weeks postoperatively: A cloud-like, uneven density, and slightly increased brightness image appears along the long axis of the defect area, which is continuous with the proximal end of the jaw bone, and the distal end of the bone appears narrow and long. The continuity is interrupted. The bone density around the titanium nails is reduced, and all the fixed titanium nails are inclined to the opposite direction of the defect area.

　　2) X-ray findings at 8 weeks postoperatively: the defect area has been replaced by partially calcified new bone, the proximal end of the jaw defect area has completed bone connection only on the lingual side, and there is continuous density reduction in the distal buccal and tongue, and the bone is not completed. connection. The volume of the new bone is obviously insufficient. The two pure titanium reconstruction plates are suspended above the new bone, the bone density around the titanium nails is reduced, and all the fixed titanium nails are inclined to the opposite direction of the defect area.

　　3) X-ray appearance at 12 weeks after operation: basically the same as the X-ray appearance at 8 weeks after operation.

　　(4) No periosteum group 10mm group

　　1) X-ray findings at 4 weeks postoperatively: Cloudy, irregular, uneven density and increased brightness can be seen in the bone defect area and protrude to the lingual side. The distal end of the bone is slightly inclined to the distal end of the titanium nail.

　　2) X-ray findings at 8 weeks postoperatively: the defect area was completely replaced by calcified new bone to complete the bone connection, the new bone on the lingual side protrudes medially, the left and right mandibles are asymmetrical, and the distal titanium nail is slightly inclined to the distal end.

　　3) X-ray findings at 12 weeks after surgery: basically similar to X-ray findings at 8 weeks after surgery.

　　(5) 20mm group without periosteal group

　　1) X-ray findings at 4 weeks postoperatively: the density of the bone defect area is reduced, and small, uneven density, calcified masses in the buccal and tongue direction, and bones are not connected in the center. The bone density around the proximal ends of the two titanium plates decreased, and the titanium nails at the distal end of the titanium plates were inclined in the same direction, and both sides of the jaw were obviously asymmetrical.

　　2) X-ray findings at 8 weeks postoperatively: the density of the bone defect area is reduced, and uneven density can be seen in the buccal and tongue calcified masses, and the bones are not connected. Both sides of the bone fractured end are uneven and uneven. The bone density around the free end of the two titanium plates decreases and the shadow expands compared with that at 4 weeks. The titanium nails at the distal end of the titanium plates tilt more obviously in the same direction. All the fixed nails Shadows appear all around, the titanium plate has lost its retention effect, the bone ends on both sides are displaced in the direction of the defect, the two sides of the jaw are obviously asymmetric, and the distance between the two sides of the mandible is shortened.

　　3) X-ray findings at 12 weeks postoperatively: A cord-like calcified mass with uneven density in the buccal and tongue direction can be seen in the center of the bone defect area. The proximal and distal ends are the bone defect areas with reduced density, and the bones are not connected. Ambiguous. The titanium plate has floated, and the tilt angle of the titanium nails in the distal direction of the titanium plate is more obvious than that at 8 weeks. All the fixed nails are displaced around, and the displacement of the bone ends on both sides toward the defect direction is more obvious. The distance on both sides of the bone is significantly shortened.

　　Experimental research results suggest that the length of segmental mandibular defects in minipigs occurs within 50mm without bone grafting. The bone connection can be completed only by in-situ osteogenesis of the periosteum. In-situ osteogenesis of the periosteum is effective for repairing mandibular defects in miniature pigs. The method is worthy of further research and discussion.