Objective To sum up the recent progress of common biodegradable internal fixation materials and to forecast the possible directions for further research. Methods The latest original articles about biomechanical properties, degradation characteristics, advantages and disadvantages of biodegradable internal fixation materials were extensively reviewed.Several common biodegradable materials were selected and expounded in different categories. Results The disadvantages of stress shielding and the second time removal, could be avoided by using biodegradable internal fixation materials instead of metal materials. Biodegradable internal fixation materials could fix fracture stably and they were ideal orthopedic internal fixation materials. Natural biodegradable polymers had excellent biocompatibil ity but poor mechanical strength. Synthetic biodegradable materials could be artificially regulated their degradation rate and had better mechanical strength, however, they had shortcomings in biocompatibil ity. Composite materials could learn from others’ b points to offset their weakness, therefore, they had pronounced advantages over the former two materials. Conclusion There still exist many problems in present biodegradable internal fixation materials although they are of great potential in its appl ication. Combining various biomaterials and using the specific processing technology to develop a biodegradable material which has better biomechanical properties, chemical properties and physical structure is the direction for future research.
Objective To investigate the effectiveness of transvertebral space and under the pedicle osteotomy for thoracolumbar kyphosis caused by old osteoporotic vertebral compression fracture (OVCF). Methods The clinical data of 11 patients with thoracolumbar kyphosis caused by old OVCF treated by transvertebral space and under the pedicle osteotomy between January 2016 and December 2020 were retrospectively analyzed. There were 2 males and 9 females, with an average age of 61.3 years (range, 50-77 years) and with a median disease duration of 8 years (range, 6 months to 50 years). Fracture reasons: 9 cases had a clear history of trauma, and 2 cases had no obvious incentive. A total of 11 vertebrae was involved in fracture, including T12 in 3, L1 in 7, L2 in 1. The operation time, intraoperative blood loss, postoperative drainage volume, and complications were recorded. Full-length X-ray films of spine and local X-ray films of the operation area were examined before operation, at 7 days after operation, and at last follow-up. The Cobb angle of thoracolumbar kyphosis was measured, and the correction rate was calculated. The visual analogue scale (VAS) score and Oswestry disability index (ODI) were recorded to assess patients’ pain and functional improvement before operation, at 1 month after operation, and at last follow-up. Results All operations were successfully completed. The average operation time was 188.6 minutes (range, 140-215 minutes); the average intraoperative blood loss was 268.2 mL (range, 100-500 mL); the average postoperative drainage volume was 615.5 mL (range, 160-1 500 mL). One patient developed bilateral thigh rebound pain after operation, which relieved after symptomatic treatment of nutritional nerve and acesodyne. All patients were followed up 14.7 months on average (range, 6-56 months). At last follow-up, osseous fusion was observed in all patients, and no fracture, loose, or displacement of internal fixator was observed on imaging. At 7 days after operation and at last follow-up, the Cobb angle of thoracolumbar kyphosis significantly improved when compared with preoperative one (P<0.05), and there was no significant difference between at 7 days after operation and at last follow-up (P>0.05); the correction rates of Cobb angle at 7 days after operation and at last follow-up were 68.0%±9.8% and 60.3%±11.9%, respectively. At 1 month after operation and at last follow-up, the VAS score and ODI significantly improved when compared with preoperative ones, and further improved at last follow-up when compared with those at 1 month after operation, all showing significant differences (P<0.05). ConclusionTransvertebral space and under the pedicle osteotomy is an effective way to treat thoracolumbar kyphosis caused by old OVCF with less trauma, shorter operation time, and less intraoperative blood loss. Patients can obtain good orthopedic results and quality of life.