Sclafani A P, Thomas J R, Cox A J, Cooper M H
Facial Plastic Surgery Center, St Louis University School of Medicine, St Louis, Mo, USA.
Arch Otolaryngol Head Neck Surg. 1997 Mar;123(3):328-36. doi: 10.1001/archotol.1997.01900030110014.
To examine the responses of subcutaneously implanted expanded polytetrafluoroethylene (e-PTFE, Gore-Tex) and porous high-density polyethylene (PHDPE, Medpor) to experimentally induced infection.
Sprague-Dawley rats were implanted subcutaneously with either e-PTFE or PHDPE implants. Inocula of Staphylococcus aureus were injected directly over the implants and the wounds were observed for clinical signs of infection. After the animals were killed, the implants were harvested and underwent Histologic examination.
Twenty-eight adult male Sprague-Dawley rats weighing 200 to 250 g.
A 8-mm diameter, 1-mm-thick implant of either e-PTFE or PHDPE was placed in a subcutaneous pocket over each animal's dorsum. Either at the time of implantation or 14 days afterward, an inoculum of 10(9) colony-forming units of S aureus was injected transcutaneously directly over each implant. The animals were observed for 7 days before being killed. The implants were harvested and examined by both conventional light and scanning electron microscopy, and the degree of capsule reaction, infection, inflammation, and implant degradation was evaluated.
Implants inoculated at the time of implantation were more likely to become clinically infected. Results for e-PTFE and PHDPE implants were similar in this group (5 of 5 e-PTFE and 5 of 5 PHDPE implants infected). The PHDPE implants inoculated 14 days after implantation were less likely to become infected (1 of 4 infected) than e-PTFE implants (3 of 4 infected), and were statistically less likely to become infected than PHDPE implants inoculated immediately after implantation (25% vs 100%; P < .02). Histologically, this resistance to infection correlated with increasing fibrovascular ingrowth into the PHDPE implants. The infected PHDPE implant had little to no ingrowth compared with PHDPE control implants. The uninfected e-PTFE implant had evidence of early fibrovascular ingrowth into the peripheral pores of the implant.
Because of differences in pore size, PHDPE promotes faster fibrovascular ingrowth. The presence of vascularized host tissue in and around the implant lends stability and resistance to experimentally induced infection. Conservative management of clinical implant infections should be considered if bacterial seeding occurs after substantial fibrovascular ingrowth is present. Future alloplast designs should include pore sizes that will encourage invasion of the implant by host tissue.
研究皮下植入的膨体聚四氟乙烯（e-PTFE，戈尔特斯）和多孔高密度聚乙烯（PHDPE，Medpor）对实验性诱导感染的反应。
将e-PTFE或PHDPE植入物皮下植入Sprague-Dawley大鼠体内。将金黄色葡萄球菌接种物直接注射到植入物上方，并观察伤口是否有感染的临床体征。处死动物后，取出植入物并进行组织学检查。
28只体重200至250克的成年雄性Sprague-Dawley大鼠。
将直径8毫米、厚1毫米的e-PTFE或PHDPE植入物放置在每只动物背部的皮下袋中。在植入时或植入后14天，将10⁹菌落形成单位的金黄色葡萄球菌接种物经皮直接注射到每个植入物上方。在处死动物前观察7天。取出植入物，通过传统光学显微镜和扫描电子显微镜进行检查，并评估包膜反应、感染、炎症和植入物降解的程度。
植入时接种的植入物更易发生临床感染。该组中e-PTFE和PHDPE植入物的结果相似（5个e-PTFE植入物中有5个感染，5个PHDPE植入物中有5个感染）。植入后14天接种的PHDPE植入物比e-PTFE植入物（4个中有3个感染）更不易感染（4个中有1个感染），且在统计学上比植入后立即接种的PHDPE植入物更不易感染（25%对100%；P < 0.02）。在组织学上，这种对感染的抵抗力与PHDPE植入物中纤维血管向内生长的增加相关。与PHDPE对照植入物相比，感染的PHDPE植入物几乎没有向内生长。未感染的e-PTFE植入物有证据表明早期纤维血管向内生长到植入物的周边孔隙中。
由于孔径的差异，PHDPE促进更快的纤维血管向内生长。植入物内部和周围有血管化的宿主组织可提供稳定性并抵抗实验性诱导的感染。如果在大量纤维血管向内生长后发生细菌接种，应考虑对临床植入物感染进行保守处理。未来的异体植入物设计应包括能促进宿主组织侵入植入物的孔径。
