Explanted Polyethylene Implants

Abstract

We would like to congratulate Dr. Chuo et al1Chuo J.Y. Dolman P.J. Ng T.L. et al.Clinical and histopathologic review of 18 explanted porous polyethylene orbital implants.Ophthalmology. 2009; 116: 349-354Abstract Full Text Full Text PDF PubMed Scopus (31) Google Scholar on their excellent histologic review of 18 explanted porous polyethylene orbital implants. We conducted a similar study on 6 porous orbital implants,2Tambe K. Pushpoth S. Mudhar H. Sandramouli S. A histopathologic study of orbital implant vascularization.Orbit. 2009; 28: 50-57Crossref PubMed Scopus (11) Google Scholar and are well aware of the complexity and time consumption in the processing of these implants.In Dr. Chuo's study, 89% of the implants contained less than 50% fibrovascular ingrowth. From the article, is unclear as to how the extent of fibrovascular ingrowth was graded, and it would be useful to know of these how many had fibrovascular ingrowth to the core, if at all. It would also be interesting to know how long these implants were in situ, as the time from surgery to implant removal varied from 4 to 168 months. In our study, all 5 porous polyethylene implants were vascularized up to the core. The time from surgery to implant removal ranged from 11 to 64 months giving a longer period for complete vascularization of the implant. This information could help us understand the rate of vascularization of porous polyethylene implants.Another useful parameter would be to know if there was a greater propensity for the implants wrapped in sclera to resist vascularization. As in our series on histological examination, we found that there was scleral remodelling and thickening of the sclera with minimal fibrovascular growth through the sclera itself.In our study, we found that despite core vascularization, infection, and necrosis did set in. Thus, demonstrating that complete vascularization does not render the implant immune to infection. We do agree with the authors that the primary cause for exposure is more likely to be mechanical pressure, and that poor vascularization has a secondary role in contributing to poor wound healing. We would like to congratulate Dr. Chuo et al1Chuo J.Y. Dolman P.J. Ng T.L. et al.Clinical and histopathologic review of 18 explanted porous polyethylene orbital implants.Ophthalmology. 2009; 116: 349-354Abstract Full Text Full Text PDF PubMed Scopus (31) Google Scholar on their excellent histologic review of 18 explanted porous polyethylene orbital implants. We conducted a similar study on 6 porous orbital implants,2Tambe K. Pushpoth S. Mudhar H. Sandramouli S. A histopathologic study of orbital implant vascularization.Orbit. 2009; 28: 50-57Crossref PubMed Scopus (11) Google Scholar and are well aware of the complexity and time consumption in the processing of these implants. In Dr. Chuo's study, 89% of the implants contained less than 50% fibrovascular ingrowth. From the article, is unclear as to how the extent of fibrovascular ingrowth was graded, and it would be useful to know of these how many had fibrovascular ingrowth to the core, if at all. It would also be interesting to know how long these implants were in situ, as the time from surgery to implant removal varied from 4 to 168 months. In our study, all 5 porous polyethylene implants were vascularized up to the core. The time from surgery to implant removal ranged from 11 to 64 months giving a longer period for complete vascularization of the implant. This information could help us understand the rate of vascularization of porous polyethylene implants. Another useful parameter would be to know if there was a greater propensity for the implants wrapped in sclera to resist vascularization. As in our series on histological examination, we found that there was scleral remodelling and thickening of the sclera with minimal fibrovascular growth through the sclera itself. In our study, we found that despite core vascularization, infection, and necrosis did set in. Thus, demonstrating that complete vascularization does not render the implant immune to infection. We do agree with the authors that the primary cause for exposure is more likely to be mechanical pressure, and that poor vascularization has a secondary role in contributing to poor wound healing. Clinical and Histopathologic Review of 18 Explanted Porous Polyethylene Orbital ImplantsOphthalmologyVol. 116Issue 2PreviewTo review the clinical and histopathologic features of porous polyethylene (PP) orbital implants requiring explantation. Full-Text PDF Author replyOphthalmologyVol. 117Issue 1PreviewWe would like to thank Dr. Sandramouli et al for their interest and comments. Full-Text PDF