BACKGROUND: Most patients with posterior pelvic and sacroiliac metastasis are terminally ill. Their treatment is usually palliative and directed toward relieving pain and improving the quality of life with the least possible intervention.OBJECTIVE: To investigate the possibility of percutaneous CT-guided fixation of sacroiliac joint with cannulated lag screw treatment for pathologic pain of sacroiliac joint.DESIGN: Preoperative and postoperative auto-control clinical trial was conducted.SETTING and PARTICIPANTS: The study was completed in Ningbo Sixth Hospital. Eight patients(4 males and 4 females, aged 12 years to 83 years)with metastatic tumor of sacroiliac joint were selected for our study.METHODS: After treatment with percutaneous CT-guided fixation of sacroiliac joint with cannulated lag screw, the sacroiliac joint of the 8 patients became pathologically unstable. Enneking pain scale was obtained preoperatively and postoperatively.MAIN OUTCOME MEASURES: Pain recovery was assessed preoperatively and postoperatively.RESULTS: After 2. 5 years' follow-up, pain of the patients was relieved with a range of 0 to 5(mean 3.2).CONCLUSION: Percutaneous cannulated lag screws with CT guidance help alleviate the patients' pain due to pathologically unstable sacroiliac joint.