[Percutaneous vertebroplasty with EH composite material: an experiment study].

ABSTRACT

OBJECTIVE: To investigate the appropriate ratio of liquid/powder and use of radiopaque agent in EH composite material for percutaneous vertebroplasty (PVP). METHODS: (1) EH composite material was divided into 6 groups. The material without contrast with the liquid/powder ratios 89, 88, and 87 was classifieds as groups I, II, and III; and the EH composite material with the liquid/powder ratios 89, 88, and 87 and with the addition of 20% barium sulfate by weight was classified as the groups IV, V, and VI. The curing temperature was measured. The bone cement of different groups was made into cylinders to be X-rayed to observe the opacity. Universal tester was used to examine the strength and stiffness. (2) The vertebrae (T8 approximately L5) were isolated from the cadaver of an elder female patient with osteoporosis. Universal tester was used to examine the strength and stiffness of the vertebral bodies (VBs). Osteoporotic vertebral compression fracture (OVCF) model was made. PVP procedure was mimicked by puncturing through the bilateral pedicle of vertebral arch into the anterior 1/3 of the vertebral bodies and the EH composite materials of the groups II and V were injected into the VBs Then the temperatures of the geometric center (CT) and spinal canal posterior wall (PT) of the VBs were measured in a water bath with the temperature of 37 degrees C. Twenty-four hours later the vertebrae underwent X-ray examination to observe the opacity and underwent examination of strength and stiffness with universal tester. RESULTS: (1) The sticking periods (?) of the groups IV, V, and VI were significantly longer than those of the corresponding groups I, II, and III respectively by about 60 s, and the highest temperature of the groups IV, V, and VI were significantly lower than those of the corresponding groups I, II, and III respectively. Addition1 of barium sulfate increased the opacity of the bone cement, but did nor significantly influence the strength of the bone cement. The properties of the group V was the best. (2) The bone cement was easy to be injected into the VBs. The peak PT was not beyond 50 degrees C. After the injection of the bone cement of the groups II, the strength and stiffness of the VB were (1501.6 +/- 5.0) N/mm and (285.6 +/-) N/mm, both significantly higher than those before the injection [(547.5 +/- 3.1) N/mm and (104.1 +/- 1.3) N/mm]; and after the injection of the bone cement of the groups V, the strength and stiffness of the VB were (1355.0 +/- 4.5) N/mm and (257.7 +/- 1.9), both significantly higher than those before the injection [(543.8 +/- 2.7) N/mm and (103.4 +/- 1.1) N/mm]. The opacity of the VBs injected with the bone cement of the group V was better than those injected with the bone cement of the group II. CONCLUSION: The EH (8/8) with 20% barium sulfate is a proper and effective filling material for the treatment of OVCF.