Wrapping hydroxyapatite implants.

Hydroxyapatite (HA) implants currently are most commonly wrapped in fresh unprocessed human donor sclera before implantation to facilitate entry into the orbital space and allow extraocular muscle attachment. Autologous temporalis fascia or autologous fascia lata are alternatives, but prolong surgery time and require a second operative site. Recently, a number of other wraps, such as processed human pericardium, processed human fascia lata, processed human sclera, bovine pericardium and expanded polytetrafluoroethylene [e-PTFE], have being marketed. Although they also facilitate implant placement, they can be costly. Polygalactin (Vicryl, Ethicon, Somerville, NJ) mesh is another readily available wrap that is easy to use and cost effective. To obtain a high success rate with this wrap, the polygalactin mesh wrapped HA implant must be moistened and seated into the orbit properly. If it is not, exposure may occur, which may explain why some surgeons shy away from its use. The proper technique is reviewed in this paper.     

Fibrovascular ingrowth into hydroxyapatite and porous polyethylene orbital implants wrapped with acellular dermis

PURPOSE: Acellular dermis is a frequently used wrapping material for hydroxyapatite (HA) and porous polyethylene (PP) orbital implants. In an animal model, we determined by histology the extent of fibrovascular ingrowth within orbital implants wrapped in acellular dermis at 6 and 12 weeks after surgery. METHODS: Four Yucatan minipigs were used for the study. Two minipigs had HA implants and two had PP implants. Implants were harvested at 6 or 12 weeks after surgery and were examined histologically for fibrovascular ingrowth. RESULTS: There was complete fibrovascularization of HA implants harvested at both 6 and 12 weeks after surgery. The PP implant harvested at 6 weeks had incomplete fibrovascularization, whereas the PP implant harvested at 12 weeks had complete fibrovascular ingrowth. There was no histologic evidence of inflammation seen in any of the orbital implants. On gross and histologic examination, the wraps were found to persist on the surface of all orbital implants, with little histologic evidence of inflammation localized to the acellular dermis. CONCLUSIONS: Acellular dermis wraps support fibrovascularization of both HA and PP orbital implants. Additionally, acellular dermis does not incite significant inflammation in association with HA and PP orbital implants and can persist in situ for at least 12 weeks after surgery.     

Bovine pericardium versus homologous sclera as wrapping materials for hydroxyapatite ocular implants: an animal study.

PURPOSE: We compared bovine pericardium and homologous sclera as wrapping materials for hydroxyapatite (HA) ocular implants in enucleated New Zealand white rabbits. METHODS: Eighteen rabbits were unilaterally enucleated and the sockets implanted with 10-mm HA spherical implants. Six implants were wrapped with homologous sclera, 6 with bovine pericardium, and 6 were not wrapped. The rabbits were killed 7 weeks later and the sockets were examined clinically for inflammation and implant exposure. Exenterated specimens were assessed histopathologically for inflammation and vascularization. RESULTS: No clinical evidence of implant exposure or extrusion was detected in rabbits receiving sclera or bovine pericardium wrapped implants. Histopathologically, the bovine pericardium displayed more inflammation in its outer portion, as well as more disruption of its lamellar arrangement than did the sclera. Fibrovascular in-growth was complete in all wrapped implants. CONCLUSION: Bovine pericardium behaves similar clinically to homologous sclera as a wrapping material for spherical HA ocular implants in a rabbit model, and may represent a reasonable alternative to sclera in such procedures in humans.     

Porous orbital implants, wraps, and PEG placement in the pediatric population after enucleation

PURPOSE: To investigate complications of various porous orbital implants and wrapping materials in the pediatric population after enucleation. DESIGN: A retrospective, comparative, nonrandomized study. METHODS: Between November 1992 and November 2006, patients younger than 15 years old were collected for study participation. They underwent enucleation with porous orbital implants primarily or secondarily at National Taiwan University Hospital. The authors used the hydroxyapatite (HA), Medpor, and Bioceramic orbital implant. The HA implant was wrapped with four different materials: donor sclera, Lyodura, porcine sclera, and Vicryl mesh. A part of HA implants and all bioceramic implants were wrapped with Vicryl mesh, added anteriorly with scleral patch grafts. All Medpor implants were unwrapped. RESULTS: Forty-seven cases had more than a two-year follow-up. The exposure rates according to implants and wraps were: donor sclera-wrapped HA (two of nine, 22%), porcine sclera-wrapped HA (three of three, 100%), Vicryl mesh-wrapped HA (one of five, 20%), and unwrapped Medpor (one of four, 25%). No exposure was found in four Lyodura-wrapped HA implants, and 22 Vicryl mesh-wrapped HA and Bioceramic implants with anteriorly scleral coating. The exposure rate was lower in cases with implants wrapped by our method and Lyodura than in those with implants wrapped by other materials (P < .001). Of 47 patients, 20 (42.5%) were fitted with peg-coupled prostheses and all had good prosthetic movements subjectively. CONCLUSIONS: Different types of implants and wraps resulted in various exposure rates in the pediatric population. The modified wrapping technique may prevent porous implants from exposure in children.     

Fibrovascularization of porous polyethylene (Medpor) orbital implant in a rabbit model

PURPOSE: To evaluate the porous polyethylene (Medpor) orbital implant in a rabbit model and compare it with three other currently available porous implants: Bio-Eye coralline hydroxyapatite (HA), FCI(3) synthetic HA, and aluminum oxide (Bioceramic). METHODS: The porous polyethylene implant was examined macroscopically and microscopically (with scanning electron microscopy). Implantation was performed in 10 adult male New Zealand albino rabbits. Each animal underwent enucleation of the right globe under general halothane gas anesthesia, followed by placement of a 12-mm porous polyethylene implant. In 5 animals, the implant was encased in polyglactin 910 (Vicryl mesh); in the other 5, it was left unwrapped. The implants were moistened in saline before placement. Implant vascularization was evaluated by histopathology at 4, 8, 12, 16, and 24 weeks. RESULTS: The porous polyethylene implant was found to have a smoother exterior surface than the Bio-Eye, FCI(3) synthetic HA, and aluminum oxide implants. Rather than a uniform interconnected porous architecture, there was an extensive system of interconnected channels through the implant, ranging in size from 125 to 1000 microm. On high-power examination there was a more solid, woven appearance without any sign of the microcrystals seen in the other porous implants. One rabbit had a retrobulbar hemorrhage after surgery and was euthanized. All the other rabbits tolerated the implant well, and there were no complications. On histopathologic examination, fibrovascularization gradually increased over time. One implant was completely vascularized at 12 weeks, and both implants harvested at 16 weeks were completely vascularized. The implant harvested at 24 weeks showed only partial vascularization (14%). CONCLUSIONS: The porous polyethylene orbital implant represents an alternative implant for use after enucleation or evisceration or for secondary implantation. In our rabbit model, the porous polyethylene implant was well tolerated without complication. Complete fibrovascularization was first seen at 12 weeks. Porous polyethylene orbital implants appear to vascularize more slowly than Bio-Eye coralline HA, FCI(3) synthetic HA, and aluminum oxide implants.     

A new variety of hydroxyapatite: the Chinese implant

PURPOSE: This study was designed to evaluate a new type of hydroxyapatite (HA) implant (produced in China) in a rabbit model. METHODS: Three New Zealand white rabbits underwent enucleation of one eye followed by implantation of a 12-mm Chinese HA implant wrapped in Vicryl mesh (polyglactin 910). Magnetic resonance imaging was performed to assess host fibrovascularization of the implant 4, 8, and 12 weeks after implantation. One animal was sacrificed at each of these times for histopathologic examination. The Chinese implant was also examined chemically and by scanning electron microscopy. It was compared to the original BioEye and the third generation synthetic HA implant produced in France by FCI (FCI3). RESULTS: This new variety of HA implant from China is heavier than the FCI3 implant but lighter than the original BioEye. The Chinese implant was easy to work with and not fragile. The pore size was more uniform than the FCI3 implant and similar to the BioEye implant clinically and by scanning electron microscopy. The pores in this implant are unidirectional. Analysis for impurities revealed a calcium oxide (CaO) content of 4.4%. Histopathologically, central vascularization occurred by 4 weeks and was similar in extent to the vascularization seen with the FCI3 implant and the BioEye. CONCLUSIONS: The Chinese implant is less expensive then the BioEye and the FCI3 implants, and appears to be a viable alternative to the BioEye. Further refinements are in progress to eliminate the CaO contaminant.     

脱细胞真皮包裹PHEMA水凝胶义眼台的实验研究

目的:研究脱细胞真皮包裹的水凝胶义眼台复合物的制备方法,评价其生物学性能。方法:材料制备:用MMA和HEMA的聚合物单体加入NaCl成孔剂制备多孔水凝胶义眼台,750mL/L乙醇浸泡制备同种异体巩膜包裹物。动物实验:新西兰白兔32只,右眼球摘除术后,16只植入脱细胞真皮包裹的直径为12mm的水凝胶义眼台作为实验组,16只植入保存异体巩膜包裹的直径为12mm的水凝胶义眼台作为对照组,术后在不同时间点(2,4,8,12wk)取材作病理检查,比较不同包裹材料对义眼台血管化程度和义眼台植入并发症发生率影响的差别。结果:MMA和HEMA的聚合物单体体积膨胀率为1.2,孔隙率为72%,孔径大小为450～520μm,且多为通孔。不同材料包裹PHEMA多孔水凝胶义眼台植入兔眶腔术后,所有32眼无肉芽肿发生及义眼台排出。光镜结果显示纤维血管组织2wk时从植入物外周长入,4～8wk时孔隙内胶原纤维逐渐致密,12wk时完成纤维血管化,扫描电镜显示植入物孔隙内逐渐被纤维血管组织填充,2wk时纤维血管组织附壁生长,12wk时孔隙内被纤维血管组织充满且孔间相连。对各组植入物纤维血管化程度进行测量,结果进行多因素方差分析,实验组较对照组血管化速度快(P=0.01)。结论:PHEMA水凝胶义眼台和脱细胞真皮生物相容性好,是一种安全可靠的眶内植入物,符合临床应用的要求,具有潜在的实际应用价值。     

增强核磁共振成像观察兔眼羟基磷灰石义眼座的纤维血管化过程研究

目的 应用增强核磁共振(MRI)动态显像技术监测兔眼羟基磷灰石(HA)义眼座完成纤维血管化的时间,以证实MRI在评价HA义眼座纤维血管化程度方面的临床应用价值.方法 健康清洁级新西兰大白兔30只,随机分为6组,均行单眼眼内容物剜出术及多孔巩膜壳内HA义眼座植入术,术后第1、2、3、4、5、6周进行增强MRI的相关检查并计算MRI图像中VE/VHA比值(VE为义眼座强化区体积,VHA为义眼座体积),于每周扫描完毕后处死1组兔,取出HA义眼座进行病理组织学的对照观察.结果 兔眼HA植入后前4周间依次比较MRI图像中VE/VHA比值显著增加,而第4周后不再增加;兔眼HA病理检查也发现术后第4周全部植入HA义眼座均完成纤维血管化,HE染色可见致密的胶原纤维形成,以及内含红细胞的新生血管,并且无明显炎症细胞浸润.结论 MRI可作为HA义眼座术后血管化程度监测的影像学依据.健康兔眼眶内植入直径12 mm的HA义眼座在4周后可达到完全纤维血管化.     

Bovine pericardium versus homologous sclera as a wrapping for hydroxyapatite orbital implants

PURPOSE: To report our experience with bovine pericardium as a wrapping material for hydroxyapatite orbital implants after enucleation and to compare the exposure rates of the implants wrapped with bovine pericardium versus donor sclera. METHODS: We retrospectively reviewed the records of all patients who received bovine pericardium-wrapped or donor sclera-wrapped hydroxyapatite implant after primary enucleation between March 1995 and December 2001. RESULTS: Of the 26 patients who received donor sclera-wrapped implants after enucleation, 1 (3.8%) had implant exposure. Of the 26 patients who received bovine pericardium-wrapped implants after enucleation, 6 (23%) had implant exposure. The incidence of implant exposure with the use bovine pericardium wrapping material was found to be significantly higher than with sclera (P = 0.05). Six of the 7 implant exposures were noted in the first 6 months after placement of the orbital implant. Five of the 6 exposed bovine pericardium-wrapped hydroxyapatite implants were associated with socket infection. The case of exposure of the sclera-wrapped implant was treated conservatively by observation. Six patients who had exposure of bovine pericardium-wrapped implants required multiple repairs because of recurrent exposures. Four of these patients eventually required removal of the implant. CONCLUSIONS: Despite the advantages of using bovine pericardium as a wrapping material for hydroxyapatite orbital implants, we observed a significantly higher incidence of exposure with bovine pericardium compared with donor sclera in the early postoperative period. Use of bovine pericardium as a wrapping material for orbital implants should be avoided unless some future modifications of the technique can be developed to prevent such complications.     

羟基磷灰石义眼台植入的手术体会

目的比较巩膜包裹羟基磷灰石(hydmxypatite，HA)义眼台植入法与带线HA义眼台直接植入法的疗效。方法眶内植入HA义眼台共58眼，用自体或异体巩膜包裹义眼台后眶内植入40眼，用带线义眼台直接植入眼眶18眼，随访3月-4年。结果义眼台暴露7眼12％(7／58)，Ⅰ期1眼，Ⅱ期6眼；6眼采用巩膜包裹植入法15％(6／40)，1眼采用带线义眼台直接植入法5．6％(1／18)。结膜囊狭窄1眼。结论HA义眼台植入术后主要并发症是义眼台暴露，用带线义眼台直接植入发生这种并发症的机率变小。     

A comparison of rates of fibrovascular ingrowth in wrapped versus unwrapped hydroxyapatite spheres in a rabbit model

PURPOSE: To compare the rate of fibrovascularization of wrapped versus unwrapped hydroxyapatite (HA) spheres in an animal model and to investigate how drilling small-diameter access holes at the time of implantation affects the rate of fibrovascular ingrowth in wrapped implants. METHODS: The right eyes of 20 New Zealand White rabbits were removed and a 12-mm HA sphere was implanted in each socket. The spheres were left bare in 8 of the animals. In the other 12, the implant was wrapped in an autologous sclera shell. In 4 animals from each group, a 1-mm diameter access hole was drilled into the spherical center of the implant at the sites of extraocular muscle insertion and at the posterior pole before implantation. All implants were explanted after 1 week. RESULTS: The mean depth of fibrovascularization in the bare group without access holes (n = 4) was 100% (SD = 0). The mean depth of fibrovascularization in the wrapped group without access holes (n = 8) was 30.1% (SD = 11.0). The difference between these two groups was statistically significant (P<0.001). The mean depth of fibrovascularization in the wrapped group with access holes (n = 4) was 91.5% (SD = 9.8). Compared with the wrapped group without access holes, the difference was statistically significant (P<0.001). The difference in the mean depth of fibrovascularization between the bare group without access holes and the wrapped group with access holes failed to reach statistical significance (P = 0.18). CONCLUSIONS: On the basis of this preliminary study, we conclude that whereas scleral wrapping does significantly slow the rate of fibrovascular ingrowth, the concomitant placement of access holes greatly improves the rate of fibrovascularization.     

羟基磷灰石义眼台纤维血管化的实验研究

目的 研究手术方式对兔眼窝植入羟基磷灰石义眼台纤维血管化的影响。方法 将36只新西兰大白兔随机分为4组，分别对其左眼实施半巩膜壳内(A组)、多孔巩膜壳内(B组)、全巩膜壳内(C组)或巩膜瓣遮盖肌锥内(D组)4种不同术式义眼台植入术。不同时间采用Tc-99MDP显像或病理检查法检测各组义眼台纤维血管化程度。结果 第1、2周及第8周，各组间平均L／R值差异无显著性意义；第4周(F=7．482，P=0．009)和第6周(F=6．676，P=0．034)，C组低于其他3组，而A、B、D组间比较差异无显著性意义。第8周病理检查各组义眼台纤维血管化程度差异无显著性意义。结论 半巩膜壳内或多孔巩膜壳内植入义眼台效果最佳。     

Brazilian hydroxyapatite implant

PURPOSE: To evaluate a synthetic hydroxyapatite (HA) (manufactured in Brazil) in a rabbit model. METHODS: Nine New Zealand white rabbits underwent enucleation of one eye followed by implantation of either a 12-mm Brazilian synthetic HA implant or a 12-mm BioEye, wrapped in polyglactin 910 mesh. Magnetic resonance imaging was performed to assess fibrovascular ingrowth 4, 8, and 12 weeks after implantation. Three animals were killed at each of the times for histopathologic examination. The Brazilian implant was also examined chemically and by scanning electron microscopy. RESULTS: The Brazilian HA was found to be heavier than either the BioEye or synthetic FCI3 HA implants. It did not have a visible, regularly arranged interconnected porous architecture. Rather, it had randomly appearing channels apparent on its external and internal surface in addition to large cystic areas within the body of the implant. Scanning electron microscopy revealed the implant to have a microporous architecture in addition to the large channels and cystic cavities. Histopathologically, central vascularization occurred by 4 weeks and was also present at 8 and 12 weeks. In three Brazilian implants an unrecognizable, nonbirefringent material was identified. The cause of it was unclear. Chemical analysis confirmed the implant to consist of pure HA. CONCLUSION: The Brazilian implant is pure HA that appears solid but has randomly arranged channels as well as a microporous architecture that allows vascularization to its center. It is heavier than other available HA implants and has the presence of an unidentified foreign material within it. Although this implant is less expensive and does not require a costly manufacturing process, the structural characteristics of the material do not offer any theoretical or clinical advantages. The implant is only available in Brazil at this time.     

Current trends in managing the anophthalmic socket after primary enucleation and evisceration

PURPOSE: To evaluate current trends in the management of the anophthalmic socket after primary enucleation and evisceration. METHODS: The active membership of the American Society of Ophthalmic Plastic and Reconstructive Surgery (ASOPRS) was surveyed regarding primary enucleations and eviscerations performed between January and December 2002. Survey questions included practice demographics, orbital implant use, wrapping materials, placement of a motility peg, reasons for implant choice, and complications encountered. RESULTS: A total of 2,779 primary orbital implants were reported, comprising 1,919 (69.1%) enucleations and 860 (30.9%) eviscerations. The high-density porous polyethylene implant was used most frequently for enucleations (42.7%), followed by coralline hydroxyapatite (27.3%) and nonporous alloplastic implants (19.9%). For eviscerations, the high-density porous polyethylene implant was the most commonly used implant (42.3%), followed by hydroxyapatite (25.9%) and nonporous alloplastic implants (25.7%). The top 3 reasons for implant choice were outcome (69.3%), cost (43.6%), and experience (39.5%). Most implants were either not wrapped (59.8%) or were wrapped in donor sclera (25.2%) or polyglactin mesh (7.2%). Pegs were used in 8.1% of all implants reported. The most frequent complications encountered for unpegged implants were exposure (3.2%) and infection (0.4%). For pegged implants, the most common complications reported were pyogenic granuloma (13.7%), exposure (5.7%), and discharge (5.7%). CONCLUSIONS: In managing the anophthalmic socket, ASOPRS survey respondents preferred to use the porous polyethylene implant after primary enucleation and evisceration. Most orbital implants were not wrapped, and most surgeons preferred not to place a motility post or peg in the implant.     

羟基磷灰石眶内植入物血管内皮细胞生长因子的表达

目的:探讨血管内皮细胞生长因子(vascular endothelial growth factor,VEGF)与羟基磷灰石(hydroxyapatite,HA)眶内植入物纤维血管化形成的相关性,以及地塞米松抑制羟基磷灰石植入物纤维血管化的机制。方法:家兔20只随机分为实验组与对照组,每组10只;各组均采用HA植入物植入兔眼眶。术后滴妥布霉素滴眼液4次/d,实验组术后48h起隔日球周注射地塞米松0·5mg和实验结束,并观察两组的结膜生长情况;实验组与对照组分别于术后3,7,14,21,28d摘取2只HA植入物行免疫组织化学检测VEGF阳性表达情况。结果:羟基磷灰石植入物纤维血管化与VEGF的表达存在显著的相关性。术后14d,实验组HA炎性细胞浸润明显减少,实验组VEGF表达明显低于对照组。结论:羟基磷灰石植入物纤维血管化与炎症反应密切相关,VEGF可能参与了纤维血管化形成过程,地塞米松可能通过抑制植入物的炎症反应及VEGF的表达。     

The Molteno M-Sphere

PURPOSE: To analyze a mammalian hydroxyapatite (HA) implant known as the Molteno M-Sphere, recently approved by the Food and Drug Administration of the United States. METHODS: The authors examined the implant macroscopically, with chemical analysis (x-ray powder diffraction, x-ray fluorescence spectrophotometry), and microscopically with scanning electron microscopy. Animal implantation of six Molteno M-Spheres was carried out in six adult male New Zealand albino rabbits. Implant vascularization was evaluated by means of magnetic resonance imaging and histopathologic sectioning. RESULTS: The M-Sphere was found to have multiple interconnected pores throughout with an average pore size of 300 microm to 600 microm. This implant was very light-weight (0.31 g) and fragile. It was made up of pure HA. Magnetic resonance imaging studies showed implant enhancement to its center by 4 weeks after implantation. Histopathologically, fibrovascularization occurred uniformly throughout the 4, 8, and 12-week rabbit implants. CONCLUSIONS: The M-Sphere is an alternative type of HA implant that recently has been reintroduced into the United States for use after enucleation, evisceration, or as a secondary implant. It has multiple interconnected pores allowing central fibrovascularization as early as 4 weeks in a rabbit model. Its light weight and fine trabecular framework, however, are associated with increased implant fragility when compared with other available HA implants (BioEye and FCI3 synthetic HA). The implant requires careful handling because routine handling may damage the implant. The implant is currently approved by the United States Food and Drug Administration.     

The use of vicryl mesh in 200 porous orbital implants: a technique with few exposures

PURPOSE: To report the results of a wrapping technique for porous orbital implants by using polyglactin 910 (Vicryl) mesh (Ethicon Inc., Somerville, NJ, U.S.A.). METHODS: We retrospectively reviewed the records of 200 consecutive patients from one author's practice who received a polyglactin 910 mesh-wrapped porous orbital implant after enucleation or as a secondary implant between October 1, 1996, and April 15, 2001. We recorded potential problems that might be attributed to polyglactin 910 mesh both before pegging (excessive inflammatory response to the material, conjunctival thinning, and implant exposure) and after pegging (exposure of the implant around the sleeve, conjunctival thinning, and implant exposure other than adjacent to the peg). RESULTS: One hundred twenty-two men and 78 women underwent placement of a polyglactin 910 mesh-wrapped porous orbital implant. The average age at the time of implantation was 48.9 years (range, 11 to 85 years). The average follow-up interval in the 200 patients was 19.4 months (range, 2 to 80 months). Thirteen of the 200 patients had less than 6 months of follow-up, leaving 187 patients with an average follow-up of 20.5 months (range, 6 to 80 months). There were 76 primary enucleations and 124 secondary orbital implants. Thirty-seven patients received a Bio-Eye hydroxyapatite implant (HA) (Integrated Orbital Implants, San Diego, Calif), 97 received a synthetic FCI hydroxyapatite implant (FCI, Issy-Les-Moulineaux, France), and 66 received a Bioceramic implant (aluminum oxide-Al2O3) (FCI, Issy-Les-Moulineaux, France). One hundred fourteen patients (57%) underwent peg placement. The average time to pegging was 9.9 months (range, 6 to 16 months). Before pegging, 4 of 187 patients (2.1%) had implant exposure. Three of these exposures followed secondary orbital implant placement (2 Bio-Eye HA, 1 synthetic FCI3 HA) and one followed an enucleation (synthetic FCI3 HA). Two patients required a temporalis fascia graft and one required a scleral patch; the remaining defect closed spontaneously. One patient had conjunctival thinning 6 months after orbital implantation, which remained stable with no frank exposure for 36 months. No patient had excess socket inflammation. After peg placement, 3 additional patients had exposure of the implant around the peg site. There were no cases of conjunctival thinning or exposure of the implant other than adjacent to the peg site. CONCLUSIONS: Polyglactin 910 mesh is an excellent option as a wrapping material for porous orbital implants. It is simple to use, readily available, eliminates the need for donor tissue, does not require a second operative site, and it is less expensive than other currently available wrapping materials. We attribute our high success rate to our technique, which emphasizes proper placement of the implant within the Tenon space, suturing the extraocular muscles anterior to their normal anatomic sites, and meticulous closure of the Tenon capsule and conjunctiva in separate layers.     

A comparative study of bovine pericardium (periguard) and homologous sclera as lower eyelid spacer graft analogs in New Zealand white rabbits

PURPOSE: To compare bovine pericardium (Periguard; Bio-Vascular, Inc., St. Paul, MN, U.S.A.) and homologous sclera as spacer graft analogs in a rabbit model. METHODS: A nonrandomized experimental animal study was conducted. Elliptical subconjunctival implants were placed in one lower eyelid each of 10 rabbits. Five rabbits received homologous sclera implants, and five received bovine pericardium implants. The rabbits were killed 7 weeks later, and the lower eyelids were examined clinically and histopathologically. RESULTS: Rabbit eyelids implanted with Periguard had a more marked inflammatory reaction and more significant collagen lamellar disruption than eyelids implanted with homologous sclera, although clinically they appeared quite similar. CONCLUSIONS: Although bovine pericardium elicited a more intense inflammatory response at the histopathologic level, both implants were similarly tolerated at the clinical level. These findings are consistent with animal and human investigations of bovine pericardium in other parts of the body, and warrant further studies into its potential use in the human eyelid.     

增强核磁共振成像观察人眼羟基磷灰石义眼座的纤维血管化过程

目的:利用增强核磁共振(MRI)动态显像技术监测人眼羟基磷灰石(HA)义眼座完成纤维血管化的时间,对HA义眼座纤维血管化的MRI图像信息和量化数据进行研究,以证实MRI在评价义眼座纤维血管化程度方面的临床应用价值。方法:选择临床行眼内容物剜除术及一期HA义眼座植入术的患者15例15眼,自第1mo开始,每月1次,连续7次,每次均由放射科医师进行增强MRI的相关检查并计算MRI(VE/VHA)比值(VE为义眼座强化区体积,VHA为义眼座体积)。结果:人眼HA植入术后前6mo间依次比较MRI图像中VE/VHA比值显著增加,第6mo后不再增加。结论:核磁共振成像(MRI)可作为HA义眼座术后血管化程度监测的影像学依据。正常人眼眶内植入直径20mm的HA义眼座在6mo后完全纤维血管化。     

Tc-99m MDP骨显像观察兔眼眶内植入羟基磷灰石义眼台纤维血管化进程

目的 采用TC-99m MDP骨显像法研究兔眼眶内植入羟基磷灰石(hydroxyapatite，HA)义眼台纤维血管化完成的自然进程，探讨义眼台纤维血管化显像特点和规律。方法 取30只新西兰大白兔左眼实施HA义眼台眼眶内植入术，义眼台直径12mm。术后第1、2、3、4、6、8周，采用Tc-99m MPD骨显像技术检查手术眼与自体对侧非手术眼义眼台相同感兴趣区放射性平均计数比值(L／R)；术后第8周取出义眼台行病理检查。结果 术后第l～4周，L／R比值依次增加，各周L／R均数间比较差异有显著性意义(F=74．91，P=0.000)。术后第4周与第6周比较，差异无显著性意义(P=0．24)，第4周与第8周比较，差异也无显著性意义(P=0.51)。术后第8周病理检查显示，全部义眼台完全纤维血管化。结论 Tc-99m MDP骨显像法能反映眶内植入羟基磷灰石义眼台纤维血管化过程，研究人眼眶内植入羟基磷灰石义眼台Tc-99m MDP骨显像规律有重要意义。