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In a previous study by our group evaluating the clinical use of Medpor implants as augmentation material in the facial skeleton, we examined cases with unexpected intense foreign body reaction and focal disintegration of the implant material. The present study evaluates the histological findings in the largest series of explanted Medpor samples from human beings so far. Altogether 10 samples were harvested during revision surgery due to aesthetic contouring or due to infection. The average time from implantation to removal of the implants was 8.1 months. Paraffin embedding was employed for improved histological analysis. Chronic inflammation and foreign body giant cell reaction were seen in all cases. Intracytoplasmatic phagocytosis of disintegrated pieces of Medpor was seen as well as focal destruction of the material. From the histological point of view it is no longer justified to regard Medpor as an immunologically inert material. Nevertheless the reaction does not seem to be severe enough to compromise the stability and volume of the implant from a clinical point of view.

Ewing sarcoma (ES) of the mandible is rare and can be mistaken for inflammation of dental origin. We present a 24-year old male patient which underwent radical tumour surgery and primary reconstruction with a microvascular osteoseptocutaneous free fibular flap as well as postoperative adjuvant chemotherapy. Incomplete osseous tumour resection required a second intervention. This case report recapitulates the clinical and histopathological findings in oral ES, demonstrates its sometimes difficult diagnosis and discusses the (dis-)advantages of primary osseous reconstruction in ablative tumour surgery.

Porous polyethylene implants showed a good fibrovascular integration without encapsulation under the light microscope. Giant cells were detected on the surface of the implants. Besides this there was evidence for resorption of the implant material. Fixation with titanium screws is very effective. No implant dislocation or implant fracture occurred. The implants showed high volume stability and were easily handled and contoured. It is not possible to visualize Medpor implants with current imaging techniques, because polyethylene shows no contrast.