The purpose of the present experiment was to observe the morphological characteristics and invasiveness of a transplantable cancer NO 27 (U 27) after serial passages about 20 years. The results were as follows: The morphological characteristics of this tumor strain was low-differentiated carcinoma which were demonstrated by light microscopy and transmission electron microscopy. In the cytoplasm the single irregular distribution of the tensile fibrils and some semi-desmosome between adjacent cells were discovered by transmission electron microscopy. Two types of cancer cells were observed on the surface of the cancer nest by scanning electron microcopy:Ⅰ), There were many microvilli on the surface of the first type cancer cells; 2). The surface of the cancer cells of the second type were more flat sometimes with single small blebs. Many cancer cells had been released from cancer cell clump after 3 days of intramuscular implantation. Later they actively invaded into the spaces between muscle fibers in the form of amebae. Some cancer cells stretched out their filopodia directly in contact with target cells. The degenerative and atrophic changes of muscle tissue appeared in the invasive area of cancer cells. Finally these changes were leading to the disappearance of the entire structure of the muscle with the replacement by cancer tissues.

Objective: To investigate the clinical effect of percutaneous curved vertebroplasty in the treatment of thoracolum-bar osteoporotic vertebral compression fractures (OVCFs). Methods: All of 85 patients with single thoracolumbar vertebral OVCFs who met the admission criteria from January 2017 to July 2018 were divided into three groups according to the random dig-its table method. They were treated with percutaneous curved vertebroplasty, routine unipedicular PVP and routine bipedicular PVP respectively. There were 25 patients in the percutaneous curved vertebroplasty group, 6 males and 19 females; aged 56-80 years, with an average age of 70.6±9.7 years. Fracture vertebral body distribution: T₁₀ 2 cases, T₁₁ 4 cases, T₁₂ 3 cases, L₁ 9 cases, L₂ 3 cases, L₃ 1 case, L₄ 1 case and L₅ 2 cases. There were 32 patients in the routine unipedicular PVP group, 6 males and 26 fe-males; aged 58-75 years, with an average age of 69.5±9.3 years. Fracture vertebral body distribution: T₁₀ 2 cases, T₁₁ 4 cases, T₁₂ 5 cases, L₁ 11 cases, L₂ 6 cases, L₃ 1 case, L₄ 1 case and L₅ 2 cases. There were 28 patients in the routine bipedicular PVP group, 5 males and 23 females; aged 59-81 years, with an average age of 69.8±8.8 years. Fracture vertebral body distribution: T₁₀ 2 cases, T₁₁ 4 cases, T₁₂ 4 cases, L₁ 10 cases, L₂ 4 cases, L₃ 1 case, L₄ 1 case and L₅ 2 cases. The operation time, injected cement volume, in-traoperative blood loss were recorded and analyzed. Preoperative, postoperative 1 week and 3 months visual analogue scale scores and oswestry disability index were adopted to value the clinical improvements. Preoperative, postoperative 1 week and 3 months relative vertebral height and kyphosis correction, and the cement leakage rate were measured and analyzed. Results: There was no significant difference in the data of gender, age, VAS scores, ODI and distribution of fracture vertebrae among the three groups (P>0.05), and the baseline data was comparable. The average VAS score in the percutaneous curved vertebroplasty group was 2.3±0.5 at 1 week after surgery, that of the routine unipedicular PVP group was 2.4±0.4 and that of the routine bipe-dicular PVP group was 2.4±0.4; the average ODI in the percutaneous curved vertebroplasty group was 19.8%±3.9%, that of the routine unipedicular PVP group was 20.0%±4.1% and that of the routine bipedicular PVP group was 19.9%±3.8%; they were lower than the preoperative data, which were statistically significant (P<0.001). The average relative vertebral height in the percutaneous curved vertebroplasty group was 48.99%±9.23% at 3 months after surgery, that of the routine unipedicular PVP group was 47.11%±10.12% and that of the routine bipedicular PVP group was 46.71%±11.16%; the average kyphosis cor-rection in the percutaneous curved vertebroplasty group was 6.21%±1.94%, that of the routine unipedicular PVP group was 5.22%±2.07% and that of the routine bipedicular PVP group was 5.97%±2.09%; there was 1 cement leakage case in the per-cutaneous curved vertebroplasty group; those of the routine unipedicular PVP group were 4 cases and those of the routine bipe-dicular PVP group were 6 cases; there was no significant difference among the three groups (P>0.05). Operation time 39.10±2.00 min vs 38.70±1.70 min, injected cement volume 3.60±0.11 ml vs 3.50±0.13 ml and blood loss 5.10±0.30 ml vs 5.00±0.40 ml of the percutaneous curved vertebroplasty group and the routine unipedicular PVP group were less than those of the routine bipedicular PVP group, which were statistically significant (P<0.05). Conclution Percutaneous curved vertebroplasty could achieve satisfactory clinical outcomes for OVCFs, with advantages of less operation time, less blood loss, limited X-ray expo-sure, less injected cement volume, and more balanced augmentation for stabilization of the affected vertebrae and total verte-bral column.