Porous materials in tissue engineering / 中国组织工程研究

BACKGROUND:A favorable application prospect has been showed in basic and clinical research of porous material implantation in recent years. OBJECTIVE:To retrospect the progress in basic and clinical research of porous materials in the past 10 years and to summarize the existing problems and clinical prospects. METHODS:A computer-based search of PubMed and CNKI databases was performed for relevant articles using the keywords of“porous material, bone implantation”in English and Chinese, respectively. The included articles were related to porous materials and composite materials used in vitro, in vivo or in clinic, as wel as porous materials closely related with bone defect repair or bone tissue engineering. RESULTS AND CONCLUSION:Hydroxyapatite, titamium and its al oys, polyethylene, calcium phosphates are porous materials that have been studied presently. Increasing experimental studies have shown that the porous materials have good histocompatibility and osteoinductive features in vitro and in vivo. But the uniform standards for porosity size in favor of tissue growth that is fastest and most effective have not been obtained. It is unclear how to gain and control the porosity of porous materials that are irregular, how to control the elasticity modulus, and how to gain 100%porosity effectively. Furthermore, whether the inflammation and exposure of porous materials in clinical application are related to the above-mentioned problems are unable to confirm.

Percutaneous vertebroplasty using instruments and drugs made in China for vertebral metastases / 中华医学杂志(英文版)

<p><b>OBJECTIVES</b>To evaluate the effect of percutaneous vertebroplasty on vertebral tumor metastasis using instruments and drugs made in China and to explore the technique of percutaneous vertebroplasty.</p><p><b>METHODS</b>Thirty-two patients with vertebral metastasis were treated with percutaneous vertebroplasty with instruments and drugs made in China. Anterolateral approach for cervical vertebrae and transpedicular approach for thoracic and lumbar vertebrae were used. The volume of disease focus and the amount of polymethy methacrylate (PMMA) injected were calculated with formula V = 4/3pi (D/2)(3) preoperatively. PMMA with contrast was mixed according to the ratio of powder/liquid/contrast of 3:2:1. The procedures were monitored under fluoroscopy. PMMA was injected in the polymerization time. CT scanning was performed before and after the operation.</p><p><b>RESULTS</b>The percentage of lesion PMMA fill was more than 50% as demonstrated by CT. Clinical data were obtained from the cases followed up for 7 - 12 months, and the rate of pain relief was 90.6% (29/32) at one week, 71.8% (23/32) at six months, and 58.6% (17/29) at 12 months after operation. There were no cases of PMMA leakage that affected clinical performance.</p><p><b>CONCLUSIONS</b>Percutaneous vertebroplasty for vertebral tumor metastasis using instruments and drugs made in China was effective. It is important to prevent paravertebral leaks of PMMA and to ensure that PMMA is injected within the polymerization time.</p>

An experimental study of percutaneous vertebroplasty using instruments and drugs made in China / 中华放射学杂志

Objective To evaluate the efficacy of percutaneous vertebroplasty(PVP) using instruments and drugs made in China, and to provide the data for the clinical application Methods Polymethylmethacrylate(PMMA) without adding contrast was classified into 3 groups according to the ratio of powder/liquid as 2∶1,3∶2,1∶1,PMMA with contrast was also classified into 3 groups according to the ratio of powder/liquid/contrast as 2∶1∶1,3∶2∶1,1∶1∶1 There were 6 groups totally The periods and temperature of polymerizing process were measured The PMMA specimens of different group were made,with the diameter of 1 0 cm, height of 3 0 cm The density was determined in X ray pictures and mechanical testing with universal testing machine was performed PVPwas performed in the spines of 3 human cadavers with transpedicular route under fluoroscopic control The PMMA was injected into vertebra at an interval of one vertebra from T4-L4, 7 vertebra were injected on each cadaver The injected volume was recorded The spines were dissected into 42 single vertebrae, with all soft tissues removed Overall,21 pairs of adjacent vertebrae were subjected to axial compression in an universal testing machine The cranial vertebra of each pair was injected with PMMA, the caudal one served as a control Results Lower temperature was observed in the PMMA groups with adding contrast than those without adding contrast during the polymerizing process, the average temperature in the PMMA group with the ratio of powder/liquid/contrast as 3∶2∶1 was 67 4℃ There was significant X ray density difference between the groups with contrast and corresponding groups without contrast ( t = 20 00, t = 20 00, t = 22 86, P 0 05) The group with ratio of power/liquid/contrast 3∶2∶1 was (127? 4 70) s in the period of the paste, and the ultimate compressive strength (mPa) was 47 23 The punctures were successfully reached in all vertebra The injected PMMA average volume was 5 ml in the thoracic vertebra and 7 5 ml in the lumbar vertebra PMMA leaking into adjacent paravertebral tissue was demonstrated in 3 of 21 vertebrae The ultimate compressive strength of the vertebrae without PMMA injection in the 3 groups was 3 28,3 63,and 3 69, respectively The ultimate compressive strength of the injected PMMA vertebrae in the 3 groups was 4 52,4 73,and 4 81, respectively The ultimate compressive strength was significantly higher in the injected PMMA vertebrae than that in the vertebrae without PMMA injection( t =3 17,3 55,3 99, P