ObjectiveTo investigate the short-term effectiveness of percutaneous pedicle fixation combined with intravertebral allograft by different methods for thoracolumbar fractures. MethodsThe clinical data of 94 patients with single segment thoracolumbar fracture who underwent percutaneous pedicle fixation combined with intravertebral allograft by different methods between October 2018 and October 2019 were retrospectively analyzed. According to the different methods of intravertebral allograft, they were divided into group A (bone grafting by Jack dilator, 40 cases) and group B (bone grafting by funnel, 54 cases). There was no significant difference between the two groups (P>0.05) in the gender, age, body mass index, cause of injury, injured segment, Wolter index, time from injury to operation, and preoperative visual analogue scale (VAS) score, injured vertebral height ratio, and Cobb angle. The operation time, fluoroscopy frequency, allograft volume, and complications were recorded and compared between the two groups. VAS score of low back pain was used to evaluate the remission of clinical symptoms before operation, at 3 days, 3 months, 12 months after operation, and at last follow-up. The injured vertebral height ratio and Cobb angle were measured before operation, at 3 days, 3 months, and 12 months after operation. ResultsThe operation time, fluoroscopy frequency, and allograft volume in group A were significantly higher than those in group B (P<0.05). No complication occurred after operation, such as loosening or fracture of internal fixation. And bone grafting in the injured vertebrae healed at last follow-up. The VAS score, injured vertebral height ratio, and Cobb angle at each postoperative time point significantly improved when compared with preoperative ones (P<0.05); compared with 3 days postoperatively, the VAS score improved further after 3 months, but the injured vertebral height ratio decreased and the Cobb angle increased, and the differences were significant (P<0.05). There was no significant difference in the VAS scores of low back pain between the two groups at each time point after operation (P>0.05); the injured vertebrae height ratio in group A was significantly higher than that in group B, and the Cobb angle was significantly lower than that in group B, all showing significant differences (P<0.05). ConclusionThe intravertebral allograft via Jack dilator can restore the height and decrease the Cobb angle of the injured vertebrae, but accompanied with higher fluoroscopy frequency and longer operation time when compared with funnel bone grafting. For patients with single level thoracolumbar fractures, intravertebral allograft via Jack dilator is recommended.
ObjectiveTo observe the effect of using tungsten drills to prepare mouse knee osteochondral injury model by comparing with the needle modeling method, in order to provide an appropriate animal modeling method for osteochondral injury research.MethodsA total of 75 two-month-old male C57BL/6 mice were randomly divided into 3 groups (n=25). Mice in groups A and B were used to prepare the right knee osteochondral injury models by using needles and tungsten drills, respectively; group C was sham-operation group. The general condition of the mice was observed after operation. The samples were taken at 1 day and 1, 2, 4, and 8 weeks after modeling, and HE staining was performed. The depth, width, and cross-sectional area of the injury site at 1 day in groups A and B were measured, and the percentage of the injury depth to the thickness of the articular cartilage (depth/thickness) was calculated. Toluidine blue staining and immunohistochemical staining for collagen type Ⅱ were performed at 8 weeks, and the International Cartilage Research Society (ICRS) score was used to evaluate the osteochondral healing in groups A and B.ResultsAll mice survived to the completion of the experiment. HE staining showed that group C had normal cartilage morphology. At 1 day after modeling, the injury in group A only broke through the cartilage layer and reached the subchondral bone without entering the bone marrow cavity; the injury in group B reached the bone marrow cavity. The depth, width, cross-sectional area, and depth/thickness of the injury in group A were significantly lower than those in group B (P<0.05). At 1, 2, 4, and 8 weeks after modeling, there was no obvious tissue filling in the injured part of group A, and no toluidine blue staining and expression of collagen type Ⅱ were observed at 8 weeks; while the injured part of group B was gradually filled with tissue, the toluidine blue staining and the expression of collagen type Ⅱ were seen at 8 weeks. At 8 weeks, the ICRS score of group A was 8.2±1.3, which was lower than that of group B (13.6±0.9), showing significant difference (t=−7.637, P=0.000).ConclusionThe tungsten drills can break through the subchondral bone layer and enter the bone marrow cavity, and the injury can heal spontaneously. Compared with the needle modeling method, it is a better method for modeling knee osteochondral injury in mice.