Abstract: BACKGROUND: According to existing clinical studies, vertebroplasty treatment with both the external pedicle approach and the pedicle approach can improve the pain and quality of life of patients with spinal compression fractures. Compared with the pedicle approach, the external pedicle approach has a freer puncture angle, and good bone cement dispersion effect can be obtained by adjusting the puncture angle.
OBJECTIVE: To compare the impact of vertebroplasty through individualized unilateral external pedicle approach and bilateral pedicle approach on the treatment of spinal compression fractures by quantifying the dispersion effect of bone cement.
METHODS: A total of 80 patients with thoracolumbar compression fracture were divided into two groups by random number table method. The bilateral pedicle group (n=40) underwent vertebroplasty through a bilateral pedicle approach, while the unilateral external pedicle group (n=40) underwent individualized vertebroplasty through a unilateral external pedicle approach. Anteroposterior and lateral X-rays of the affected vertebrae from two groups of patients were photographed to assess effect and type of bone cement dispersion within 3 days after surgery. Visual analog scale score, tenderness threshold around fracture, and Oswestry dysfunction index were assessed before, 1, 7 days, and 1 month after surgery. 
RESULTS AND CONCLUSION: (1) Dispersion effect of bone cement in unilateral external pedicle group was better than that in bilateral pedicle group (P < 0.001), and the amount of bone cement perfusion was higher than that in bilateral pedicle group (P < 0.001). In the bilateral pedicle group, the bone cement dispersion types were mainly concentrated in type I and type III, while in the unilateral external pedicle group, the bone cement dispersion types were mainly concentrated in type I and type II, and there was a significant difference in bone cement dispersion types between the two groups (P < 0.001). (2) Postoperative visual analog scale scores and Oswestry disability index of both groups were lower than those before surgery (P < 0.001), and postoperative tenderness threshold around fracture showed a trend of decreasing first and then increasing. At the same time point after treatment, there were no significant differences in visual analog scale score, Oswestry disability index, and tenderness threshold around fracture between the two groups (P > 0.05). (3) The results indicate that individualized vertebroplasty via unilateral external pedicle approach can achieve better bone cement dispersion, and the treatment effect is consistent with the vertebroplasty via classical bilateral pedicle approach.

Key words: spinal compression fracture, percutaneous vertebroplasty, bilateral pedicle approach, unilateral external pedicle approach, bone cement dispersion, osteoporosis