OVCF is a common and frequently-occurring disease in the elderly. For acute fresh fractures, patients tend to be treated with minimally invasive vertebral augmentation, and studies have confirmed that satisfactory results can be achieved . For the treatment of old OVCF, there is no international consensus. As mentioned earlier, many scholars have proposed classification for old OVCF, but there are many problems as follows: 1) The classification lacks clinical manifestations such as nerve damage; 2) There is no corresponding treatment plan for typing; 3) There is a duplication between the types, which does not guide clinical treatment well; 4) There is no specificity in the classification, which also contains high energy injury fractures. Therefore, based on the previous research, our study proposes five new types of grades, and proposed corresponding treatment plans for the grades.
Vertebral augmentation (VA) mainly includes percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty (PKP) . In meta-analysis in 2006, 19 studies on the treatment of OVCFs by PVP were included, involving a total of 2,086 patients. The results showed that the postoperative VAS of the patients was significantly improved, and the incidence of surgical complications was less than 1% . Another meta-analysis published at the same time included 1,710 VCFs patients who had received PKP, and the postoperative VAS of the patients was significantly reduced, and the vertebral height and kyphosis were also improved . In 2016, Clark's  prospective randomized controlled study showed that the pain relief in the surgery group was more obvious than that in the conservative treatment group, with a statistically significant difference. In this study, the cavities in the vertebral body were visible in the imaging examination for the patients of grade I. The local instability of the fractured vertebral body resulted in intractable low back pain. For the reasons of symptoms, vertebral augmentation was performed according to the literature recommendation . To our satisfaction, the postoperative pain was significantly relieved.
The key destination of posterior reduction fusion internal fixation was to fix unstable segments. The advantages of starting from the posterior approach are less bleeding, less trauma, and simple access. At the same time, the front, middle and back are fixed at three ends. It has excellent mechanical properties, realizes the effect of three-dimensional fixation, and can often achieve anatomical reduction in cases that are difficult to reduce . In this study, the dynamic position film of the patients with grade II showed obvious pseudo-joint movement, and the pain was related to the change of movement or body position. Therefore, this type of patient undergoes posterior reduction fusion internal fixation, and if necessary, combined with vertebral augmentation, to achieve the purpose of stabilizing the spine and alleviating the pain caused by height loss and local instability. Finally, the joint was fixed and fused with the nail rod to eliminate the movement of the prosthesis. In this study, the SI of the injured vertebra of 60 patients was improved from 72.82±7.78 to 84.17±5.30, the height of the injured vertebra was recovered satisfactorily, and the stability of the spine was well reconstructed, with an exact effect.
Posterior decompression and reduction fusion and internal fixation is based on reduction fixation for decompression and the most common approach is from the back to the spine. During the procedure, the surgeon makes a longitudinal incision in the back, first connecting the screw and/or bone hook to the vertebral body, and then attaching the rod to the screw and/or bone hook. Finally, the bone graft is placed on the spine after orthopedic fixation to ensure postoperative fusion of the orthopedic site. Grade III patients were accompanied by nerve damage, and imaging showed spinal canal stenosis. The purpose of surgery was to relieve nerve compression and restore spinal stability. Previous, Park et al depicted that this surgery was effective in relieving delayed neurologic compromises . Besides, Lee et al. had shown that posterior decompression and reduction fusion and internal fixation can relieve spinal cord compression and nerve compression . In our study, the postoperative follow-up patients showed significant relief of lower back pain, and the 10 patients with significant nerve injury showed significant improvement in postoperative AISA grading, which was consistent with the previously reported results.
Patients with grade IV had local instability of the vertebral body, and the biomechanics of the spine was destroyed [20, 21]. Later, the secondary collapse caused kyphosis, accompanied by low back pain, and even serious nerve damage . For patients with this grade, the goal of surgery was to correct kyphosis and restore sagittal balance. In our study, we performed posterior osteotomy with internal fixation and fusion, and the results were consistent with that reported by , which was satisfactory. However, Uchida K et al. advocated the anterior orthopedic surgical strategy  and believed that the anterior medial column was the key site of spinal deformity in patients with old fractures, and the anterior surgical approach could achieve the purpose of decompression and orthopedic more directly and thoroughly. For these different viewpoints, we need to pay attention to the fact that anterior surgery is more traumatic and more complicated than posterior surgery. Currently, posterior surgery is mostly used. For the surgeon, the posterior anatomy is more familiar, the surgical trauma is less, and simple posterior surgery can also achieve similar effects to the combined approach . The conditions of grade V patients were more complicated, with mixed symptoms. Therefore, the method of treatment should be determined based on the main symptoms. In this study, 18 patients received posterior surgery, including 12 patients with severe kyphosis who underwent posterior osteotomy and fusion and internal fixation, and 6 patients with severe spinal stenosis who underwent posterior decompression and internal fixation, all of which achieved satisfactory results.
Since most patients are associated with severe osteoporosis, postoperative complications such as screw loosening and vertebral height loss may occur. Therefore, anti-osteoporosis treatment is particularly important in the treatment of old OVCF. Studies have shown that the technique of bone cement augmentation can significantly improve the pull-out resistance of the screw . Therefore, according to the bone condition of patients, some patients were augmented with bone cement. From the follow-up findings, the surgical method has achieved remarkable results. However, there were still patients with postoperative height loss of injured vertebra, which was speculated to be related to the patient's failure to strictly follow the doctor's advice on anti-osteoporosis treatment.
There are some limits in our study. First, there are fewer cases included in the study and the follow-up time was not long enough. In addition, the long-term efficacy of the surgery needs to be verified with longer follow-up. Second, this study is a single-center study, and the experience of the surgeon and personal preference may cause differences in results.