【摘要】 目的：运用B超评估受体对无眼眼眶植入凝胶聚乙烯义眼台和多孔聚乙烯义眼台的反应。方法：兔36只行单侧眼内容物剜除并凝胶聚乙烯义眼台或多孔聚乙烯义眼台植入术，术后每周进行临床检查，术后30，60，90d行B超检查。结果：植入凝胶聚乙烯义眼台的兔除1只外，义眼台全都脱出，可能是凝胶义眼台吸水后体积增大造成的。B超检查显示随访期间凝胶义眼台内部无血管。植入多孔聚乙烯义眼台的兔有5只(27.8%)，术后30d发生义眼台脱出。根据B超检查，多孔聚乙烯义眼台显示结构不规则有异质性，回声与血管组织类似。结论：如何确定植入兔无眼眼眶的凝胶聚乙烯义眼台的最佳大小，还需要进一步研究。我们的研究显示，B超能有效评估无眼球眼眶植入的义眼台，为进一步的活体研究提供了有用信息，有可能取代其他评估义眼台血管化的昂贵检查。
【关键词】 聚乙烯义眼台 B超 兔 无眼眼眶
INTRODUCTION
Many different materials have been suggested to replace volume in the anophthalmic cavity and the integrated spheres, mainly the porous polyethylene, were the focus of the researches in the last years[1] . However, the porous polyethylene has a rough surface and conjunctival dehiscence can take place when prosthesis contact with the conjunctiva occurs.
A gel polyethylene implant was then thought in order to create a less traumatic contact between the implant and the conjunctival mucosa[2].
The integrated implants present progressive vascularization into the spheres, resulting in spherehosted integration. This integration pattern has been evaluated before by expensive methods, including computerized tomography scan and/or magnetic resonance imaging[35].
The purpose of this study was: 1) to evaluate clinically the gel and porous polyethylene spheres implanted in enucleated cavities of rabbits and; 2) to evaluate the host response integration pattern of the implants using B scan ultrasound.
MATERIALS AND METHODS
An experimental study was performed using 36 Norfolk albino rabbits. The procedures and the animals maintenance were in accordance with the ARVO resolution on Use of Animals in Research and approved by a local Ethics Committee.
The animals underwent unilateral enucleation followed by implantation of 12mm spheres of gel polyethylene (Polietigel Homus BiotecnologiaSP, Brazil) (18 animals) or porous polyethylene (Polipore Homus BiotecnologiaSP, Brazil) (18 animals).
Both spheres were composed of the same chemical structural material, but the gel implants were recovered with a membranelike structure which was used to contain the gel or semiliquid state polyethylene.
Surgical procedure: All animals were submitted to surgeries under general anesthesia and performed by the same surgeon. The right eye of each rabbit was enucleated and an unwrapped polyethylene spheregel or porouswas implanted. The conjunctiva and Tenon capsule were closed using a non absorbable 60 (PolycronEthicon) running suture. The animals were sacrificed 90 days after surgery.
Methods of evaluation: The animals were submitted to clinical examination weekly and to B ultrasound evaluation on 30, 60 and 90 days after the surgical procedure.
Statistical Analysis The results were submitted to Occurrence Frequency analysis[6].
RESULTS
Gel Polyethylene Spheres
Clinical evaluation All rabbits with gel polyethylene spheres, except one (94.4%), showed implant extrusion between 15 and 90 days after surgery (average of 20 days). Although the initially implanted spheres had 12mm in diameter, the expulsed spheres showed around 20mm. Orbital infection or inflammation was not observed in any of these animals.
Ultrasound evaluation The gel polyethylene spheres did not present vascularization during the following period, showing low reflectivity image inside the implant and high reflective pattern posterior to the implant until 90 days after the surgery (Figure 1).
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