Porous Polyethylene Orbital Implants Research Articles

Burnishing of exposed porous polyethylene orbital implant: is it useful?

ObjectifDécrire les résultats chirurgicaux du brunissage d'implants orbitaires en polyéthylène poreux (PP) qui ont été exposés. MéthodesOn a procédé à une revue de synthèse rétrospective de patients consécutifs du Hong Kong Eye Hospital et du Queen Elizabeth Hospital de Hong Kong dont l'implant orbitaire en PP a dû être réparé en raison d'une exposition entre janvier 2002 et avril 2022. On a eu recours à une perceuse électrique pour réaliser le brunissage des implants orbitaires en PP exposés. La zone exposée a été recouverte d'une greffe sclérale provenant d'un donneur, et la plaie conjonctivale a ensuite été refermée. Les patients dont le fornix palpébral inférieur était peu profond ont subi d'autres interventions pour approfondir le fornix afin de mobiliser la conjonctive et d'assurer un recouvrement approprié de l'implant. RésultatsAinsi, les implants orbitaires en PP de 6 patients, qui ont été exposés suite à une énucléation (n = 4) ou une éviscération (n = 2), ont été réparés. Aucune récurrence ne s'est produite chez 5 des 6 patients après un suivi moyen de 25 mois (fourchette : 7-42 mois). Le 6e patient, atteint d'une endophtalmie, a subi une nouvelle exposition de l'implant orbitaire 16 mois après la réparation initiale; la prise en charge a reposé sur la réinsertion d'un implant en acrylique avec un emballage réalisé par une greffe sclérale provenant d'un donneur et une greffe dermo-graisseuse. ConclusionNous avons décrit une technique de brunissage pour réparer des implants orbitaires en PP qui ont été exposés. Notre technique est facile à utiliser et empêche efficacement une nouvelle exposition de l'implant.

Chocolate Cysts Associated With Porous Polyethylene Orbital Implants.

Late-onset orbital hemorrhage is a rare complication of alloplastic implant use in orbital wall reconstruction following trauma. The authors report 3 patients with chocolate cysts presenting 3 to 9 years after orbital fracture repair with porous polyethylene implants. All patients were managed by implant removal and evacuation of cyst contents. Complete excision of the cyst was performed in 1 patient, while partial excision of the capsule was performed in 2 patients. Improvement of symptoms associated with the mass effects of the cyst was noted after surgical intervention. The authors also report the first case of orbital volume expansion from a chocolate cyst associated with a nonbarriered porous polyethylene implant. Delayed hemorrhage with capsule formation, although extremely rare, is a possible complication following orbital fracture repair with porous polyethylene implants.

Comparison of Clinical Results and Pathological Examinations Between Locally Synthesized Bone-derived Hydroxyapatite and Medpor® Orbital Implants in Animal Models.

We aimed to compare clinical and pathological reactions towards locally synthesized bovine bone derived from hydroxyapatite (bone docosahexaenoic acid (dHA)) and commercially available porous polyethylene (Medpor®, Porex Surgical Incorporation, Georgia, USA) orbital implants in animal models. An experimental study was performed on 14 New Zealand white rabbits. Group A (n=7) was implanted with bovine bone dHA and group B (n=7) was implanted with Medpor®. Clinical examinations were performed on Days 1, 7, 14, 28, and 42 post-implantation. The implanted eyes were enucleated on Day 42 and were sent for pathological evaluation. Serial clinical examinations included urine color and odor; feeding and physical activity demonstrated normal wellbeing in all the subjects. Localized minimal infection was observed in both groups during the first two weeks following implantation, and the subjects responded well to topical moxifloxacin. Both groups exhibited evidence of wound breakdown. No signs of implant migration or extrusion were observed in either group. The histopathological examination revealed no statistically significant difference in inflammatory cell reactions and fibrovascular tissue maturation between both types of implants. However, all (100%) of the bovine bone dHA implants displayed complete fibrovascular ingrowth compared to Medpor® implants (57.1%) at six weeks post-implantation (p=0.001). In conclusion, bovine bone dHA and Medpor® orbital implants were well-tolerated clinically and displayed similar inflammatory reactions and fibrovascular tissue maturation. Locally synthesized bovine bone dHA orbital implants displayed significantly greater complete fibrovascular ingrowth in comparison with Medpor® implants.

Exposure rate of smooth surface tunnel porous polyethylene implants after enucleation.

To determine the exposure rate after enucleation using the smooth surface tunnel (SST) and SST-EZ porous polyethylene (PP) orbital implants (Stryker Kalamazoo, MI, U.S.A.). The authors performed an institutional review board-approved retrospective review of 150 consecutively placed SST and SST-EZ PP implants after enucleation. Patient records were reviewed for comorbidities, surgical details, follow-up length, and presence of implant exposure. All prior published studies on porous orbital implant insertion were reviewed, and the exposure rate for patients undergoing enucleation with primary implant insertion was studied for comparison. Of the 150 implants, 30 were excluded due to follow up of less than 8 weeks. Of the remaining 120 implants, 4 (3.3%) became exposed during the follow-up period (mean, 2.1 years), 2 of which were in children who underwent chemotherapy for retinoblastoma. The authors calculated a 7.1% exposure rate for all porous implant materials placed primarily after enucleation from 58 previously published studies. The SST and SST-EZ PP implants are well tolerated when placed at the time of enucleation. The theoretical advantage of a smooth anterior surface may indeed lead to a lower rate of exposure compared with standard unwrapped porous materials as demonstrated by the relatively low exposure rate using this implant.

The Effects of Commodified Growth Factor Products on the Fibrovascularization of Porous Polyethylene Orbital Implants

Purpose: To investigate the effects of commodified growth factor products used clinically on fibrovascular ingrowth into porous polyethylene orbital implants. Methods: Porous polyethylene orbital implant sheets (Medpor) soaked with Nepidermin (Easyef), Trafermin (Fiblast), and normal saline were implanted into the backs of 18 Sprague-Dawley rats. The degree of fibrovascular ingrowth as observed using a light microscope was compared 1 and 2 weeks after implantation and was calculated as a percentage of the fibrovascular ingrowth length. Results: One week after implantation, the percentage of fibrovascular ingrowth length was 25.33 ± 5.43%, 22.56 ± 5.30%, and 21.78 ± 4.66% in the Easyef-, Fiblastand normal saline-soaked groups. The degree of fibrovascularization was higher in the Easyef-soaked group than in the other groups (p = 0.020, 0.012). Two weeks after implantation, the degree of fibrovascularization was 98.33 ± 5.00%, 100.00 ± 0.00%, and 95.89 ± 4.57%, which was significantly higher in the Easyef-, and Fiblast-soaked groups than in normal saline-soaked group (p = 0.019, <0.001). Conclusions: Commodified growth factor products used in other areas selectively enhanced fibrovascular ingrowth to a greater degree and earlier in ophthalmic plastic and reconstructive surgery. J Korean Ophthalmol Soc 2014;55(9):1366-1371

Outcome of smooth surface tunnel porous polyethylene orbital implants (Medpor SST) in children with retinoblastoma

AimTo evaluate the surgical outcome after the insertion of smooth surface tunnel porous polyethylene orbital implants (Medpor SST) in children with retinoblastoma.Methods44 consecutive children with retinoblastoma who underwent primary enucleation...

Rate of Vascularization and Exposure of Silicone-capped Porous Polyethylene Spherical Implants

This pilot study examines the rates of exposure and fibrovascular ingrowth of silicone-capped, porous, polyethylene orbital implants in the New Zealand white rabbit animal model. Unwrapped, silicone-capped, porous, polyethylene orbital spheres were implanted in 16 enucleated rabbit orbits. Four implants were removed at 3, 6, 9, and 12-month intervals and submitted for histopathologic analysis. A board-certified pathologist reviewed and graded vascular ingrowth, inflammation type, and severity for all specimens. Fibrovascular ingrowth in the center of all implants occurred as early as 3 months. No fibrovascular ingrowth occurred at the interface between the silicone cap and the porous polyethylene implant. The overlying Tenon's and conjunctival tissues remained intact without significant host inflammatory response. No implant exposure occurred at any time point. Silicone-capped porous polyethylene orbital implants appear to offer an inexpensive, easy-to-manufacture implant that resists exposure without the need for a wrapping material and achieves successful biointegration soon after implantation.

Long-term surgical outcomes of porous polyethylene orbital implants: a review of 314 cases

PurposeThis study reports on the long-term surgical outcomes after the insertion of porous Medpor orbital implants into anophthalmic sockets.MethodsA retrospective chart review of 314 eyes from 314 patients who underwent...

This issue of Acta, printed and electronic

The illustrations on the cover show adaptive optic images of photoreceptor pattern in the retina as well as infrared reflectance and high definition spectral domain optical coherence tomography images described in the letter by Massamba et al. in the electronic part of the journal. Witmer et al. in Florida review acute retinal necrosis and emphasize that in addition to retinal detachment, macular edema and ischemia, optic neuropathy is an important component. Seland et al. in Norway and several European countries found that visual impairment in Europe was <3% in prevalence and blindness ranged in prevalence from 0.5% to 2%, more in southern than northern Europe. Falk et al. in Finland report that intraocular pressure decreases by about 3 mmHg following cataract surgery and remains at this level for 4 years. Yoshino et al. in Tokyo found good and stable visual outcome with a refractive aspheric silicone multifocal intraocular lens. Heussen et al. in Germany, UK and Switzerland compared vitrectomy and scleral buckling for retinal detachment. In phakic eyes vitrectomy has more reoperations, whereas in pseudophakic eyes scleral buckling has more reoperations than vitrectomy. Velikay-Parel et al. in Austria used encircling band, laser, perfluorcarbon and silicone oil for complicated retinal detachments with proliferative vitreoretinopathy. Yeh et al. in Taiwan found that intravitreal bevacizumab treatment may reduce the need of revitrectomy for recurrent vitreous hemorrhage after diabetic retinopathy. Matri et al. in Tunisia found bevacizumab to be useful for choroidal neovascularization in angioid streaks. Mekjavic et al. in Slovenia report good results with 3 monthly bevacizumab injections followed by OCT guided continuous treatment for neovascular age-related macular degeneration. Degenring et al. in Germany attempted to translocate retinal pigment epithelium and choroid to treat neovascular AMD, with variable and disappointing results. Rojas et al. in Spain found that treatment with statin reduced choroidal damage and ischemia in hypercholesterolemic rabbits. Teuchner et al. in Austria, Hungary and USA injected brain derived neurotrophic factors and other potentially neuroprotective molecules into the vitreous cavity in rats in order to delay ganglion cell loss. Martinez-de-la-Casa et al. in Spain found that rebound and noncontact tonometry gave similar results as Goldman applanation tonometry and were similarly influenced by central corneal thickness. Wang et al. in Copehagen and China show that cyclooxygenase-2 is expressed in normal human eyes and less so in some eye tumors. Kim et al. in Korea report good outcomes with porous polyethylene orbital implants. Ganesh et al. in Oman and Sweden found that 21% of patients who had esotropia surgery in childhood later developed exotropia. Swan et al. in USA comment on this article in a letter to the editor. Theodossiadis et al. in Athens document spontaneous closure of macular holes. Following is the electronic part of this issue, which is available on http://www.actaophthalmologica.com. Resch et al. in Austria and Germany found that reduced optic nerve head bloodflow is associated with worsening visual field defect and morphological changes in the optic disc. Cause and effect is unclear. Jindal et al. in USA did not find statistically significant improvements in perimetry or multifocal visual evoked potential with acute lowering of intraocular pressure. Thaler et al. in Germany and Poland demonstrate neuroprotective effects of tempol in optic nerve crush in rats. Inoue et al. in Japan found that both refractive and diffractive multifocal intraocular lenses reduced contrast of the retinal image. Filho et al. in Brazil report that intravitreal ranibizumab reduces fluorescein leakage and macular swelling sometimes associated with panretinal photocoagulation. Chrysanthi et al. in Greece and UK measured macular pigment optical density in patients with wet and dry age-related macular degeneration. Alnawaiseh et al. in Germany and USA report that Ni++ and Ca++ channels contribute to transretinal signaling in the mouse. Brignole-Baudouin et al. in France and Italy report that omega 3 and omega 6 fatty acid supplements may improve dry eye symptoms. Gatzioufas et al. in Germany comment on the paper by Fahnehjelm et al. on corneal hysteresis and Fahnehjelm and Chen reply. Swan et al. in USA comment on the strabismus paper by Ganesh et al. in this issue. Larsen et al. Copenhagen describe myofibroma of the orbit in a 1 year old. Massamba et al. in France used adaptive optics to image macular telangiectasia, as seen on the cover of the journal. Gibson et al. in UK describe negatively results in AMD genetics. Zarnowski et al. in Poland used topical bevacizumab to prevent bleb failure following trabeculectomy. Jonas et al. in Germany and Italy used intravitreal bevacizumab successfully for perifoveal telangiectasia. I hope that you find this issue of Acta to be educational and enjoyable. Please take advantage of both the printed and electronic version of the journal. Also keep in mind that older versions of Acta Ophthalmologica are available under http://www.actaophthalmologica.com where you can read interesting publications dating back to the 1920s.

Reply re: “Comparison of the Exposure Rate of Wrapped Hydroxyapatite (Bio-Eye) Versus Unwrapped Porous Polyethylene (Medpor) Orbital Implants in Enucleated Patients”

Mazloumi, Mehdi M.D., M.P.H.; Rajabi, Mohammad Taher M.D.; Khalilzadeh, Omid M.D., M.P.H. Author Information

Re: “Comparison of the Exposure Rate of Wrapped Hydroxyapatite (Bio-Eye) Versus Unwrapped Porous Polyethylene (Medpor) Orbital Implants in Enucleated Patients”

Nasser, Qasiem J. M.D.; Blaydon, Sean M. M.D., F.A.C.S.; Connor, Michael A. M.D.; Nakra, Tanuj M.D.; Shepler, Todd R. M.D.; Neuhaus, Russell W. M.D.; Shore, John W. M.D., F.A.C.S. Author Information

Comparison of the Exposure Rate of Wrapped Hydroxyapatite (Bio-Eye) Versus Unwrapped Porous Polyethylene (Medpor) Orbital Implants in Enucleated Patients

To compare the exposure rate of wrapped hydroxyapatite versus unwrapped porous polyethylene orbital implants in enucleated patients. Medical records of the patients who underwent primary placement of hydroxyapatite (Bio-Eye) or porous polyethylene (Medpor) orbital implants after enucleation between 2002 and 2005 in Farabi Eye Hospital were reviewed, and the occurrence of implant exposure during follow-up visits was recorded. The exclusion criteria were secondary implantation, evisceration, or follow up of less than 1 year unless the exposure had occurred in the year after surgery. In the hydroxyapatite group, the implants were wrapped either in Mersilene mesh (65%) or in donor sclera (35%). Wrapping was not performed for any patient in the porous polyethylene group. A total of 198 cases with hydroxyapatite and 53 cases with porous polyethylene implant were identified. The most common causes of enucleation in both groups were globe trauma and painful blind eye. Rate of exposure was significantly higher [odds ratio (OR) = 7.97, p < 0.001] in patients with porous polyethylene (34.0%) than in those with hydroxyapatite implant (6.1%). This association remained significant after adjustment for potential confounders. Mean time of exposure after surgery was significantly (p < 0.001) longer in patients with porous polyethylene implant. Kaplan-Meier plots depicted a significantly (p < 0.001) higher rate of exposure in patients with porous polyethylene implant during the follow-up time. Unwrapped porous polyethylene implants demonstrated a higher rate of exposure, and longer time interval to exposure, compared with wrapped hydroxyapatite implants.

The Effect of Autologous Serum Eye Drops on the Conjunctivalization over Exposed Porous Polyethylene Orbital Implant (Medpor®) in the Rabbit Model

Purpose: To assess the efficacy of autologous serum eye drops (AS) in enhancing conjunctivalization over a scleral patch graft on exposed porous polyethylene orbital implant (Medpor®).Methods: Eighteen rabbits were underwent evisceration, implantation of Medpor® and homologous scleral patch graft. The conjunctival edge was sutured leaving 5 mm-diameter circular defect. In group A, 20% AS were applied 8 times a day and only balanced salt solution was applied in group B. Digital anterior segment photography was obtained 1, 3, 7, 10, 14, and 21 days after surgery and analyzed with Image Pro Plus® software.Results: In the early postoperative period, the average conjunctival growth rate (mm2/day) was faster in group A, but failed to show statistical significance (3.79 vs. 3.03, p = 0.26 in 1~3days, 2.39 vs. 1.80, p = 0.59 in 4–7days, 0.03 vs. -0.02, p = 0.94 in 7–10 days, Mann-Whitney test). The complete healing rate was higher (67% vs. 56%, p = 0.5, Fisher’s exact test) and the mean elapsed time for complete healing (days) was shorter in group A (17.3 vs. 18.2, p = 0.83, Mann-Whitney test), but did not show a statistically significant difference.Conclusion: In a rabbit model, 20% AS did not appear to facilitate the healing of small conjunctival defects of exposed porous orbital implant.

Effect of stem cells and fibrin concentration on the vascularization of the Medpor orbital implant

To determine the effect of adipose-derived adult stem cells (ADASCs) and optimal concentration of fibrin on fibrovascular ingrowth into porous polyethylene orbital implants (Medpor). Medpor sheet treated with O.25% fibrin only and ADASCs in mixtures containing fibrin (0.25%, 0.5% or 1.25%) were applied to a Medpor sheet and implanted in the back of each of 20 athymic nude mice. After 10 days, implants were removed and observed for fibrovascularization and stability. Haemoglobin, collagen and cellular DNA content were determined in quantitative assays. Haemoglobin, collagen and cellular DNA levels were significantly higher in ADASC group than in the cell-free implant (0.25% fibrin only) group (P < 0.01). The level of haemoglobin and collagen content was significantly higher in the ADASC + 0.5% fibrin group among the ADASC and fibrin mixtures (P < 0.01). ADASCs significantly improved fibrovascularization on Medpor compared with implants alone. Fibrin, used together with ADASCs to potentiate fibrovascularization, was most effective at concentrations of 0.5%.

Orbital Implants Insertion to Improve Ocular Prostheses Motility

The objectives of this study were, through a literature review, to point the differences between orbital implants and their advantages and disadvantages, to evaluate prosthesis motility after orbital implants are inserted, and to point the implant wrapping current risks. Sixty-seven articles were reviewed. Enucleation implants can be autoplastics or alloplastics and porous (including natural and synthetic hydroxyapatite [HA]) or nonporous (silicone). Hydroxyapatite is the most related in the literature, but it has disadvantages, too, that is, all orbital implants must be wrapped. Exposure of the porous orbital implant can be repaired using different materials, which include homologous tissue, as well as autogenous graft, xenograft, and synthetic material mesh. The most used materials are HA and porous polyethylene orbital implant. The HA implant is expensive and possibly subject corals to damage, different from porous polyethylene orbital implants. Porous implants show the best prosthesis motility and a minimum rate of implants extrusion. Implant wraps can facilitate smoother entry of the implant into the orbit and allow reattachment of extraocular muscles. They also serve as a barrier between the overlying soft tissue and the rough surface of the implant, protecting implants from exposure or erosion.

A Histopathologic Study of Orbital Implant Vascularization

Purpose: To histopathologically assess the extent and pattern of vascularization of explanted porous polyethylene (PP) and hyrdoxyapatite (HA) orbital implants. To compare the vascularization in PP implants harvested after enucleation versus after evisceration. Methods: This is a comparative case series of six orbital implants explanted between 11 months and 5 years and 4 months post implantation. The implants were subjected to histopathological examination with various stains, after complete decalcification. Results: There were 2 post evisceration, 3 post enucleation and 1 secondary implant. The size of the implants varied from 18 to 23 mm diameter. The reason for explantation was exposure in all the 6 cases with additional infection in 2 cases. Histopathology revealed complete vascularization up to the core of the implant in all the cases. There was evidence of chronic inflammation within all the explanted specimens. Acute inflammation was present at the site of exposure in four of the implants. Three of these implants had additional evidence of necrosis. Two cases with clinically evident infection had Gram positive cocci within the implant. Foreign-body type giant-cells, melanophages and haemosiderin laden macrophages were also observed. Eviscerated specimens showed scleral remodelling and thickening. Conclusion: All the implants were vascularized up to the core. There was histologic evidence of chronic inflammation in all the explanted implants possibly indicating the foreign nature of the implant material. The sclera did not impede vascularization of the implants in eviscerated specimens. We found no difference in the degree of vascularization of the implant in enucleated versus eviscerated implants.

Clinical and Histopathologic Review of 18 Explanted Porous Polyethylene Orbital Implants

To review the clinical and histopathologic features of porous polyethylene (PP) orbital implants requiring explantation. Case series. Eighteen explanted PP orbital implants of 18 patients were studied. The charts and histopathologic findings were reviewed for all patients requiring explantation of PP orbital implants between 1997 and 2006 by 2 oculoplastic surgeons at the University of British Columbia. Clinical data obtained included patient demographics, the nature of the primary surgery, and the clinical presentation leading to eventual implant removal. The histopathologic data observed included the presence of anterior exposure, area of fibrovascular ingrowth, type of inflammation, and presence and type of bacterial colonies. Nine (50%) of the 18 patients studied were referred from other surgeons. The balance represented 3.2% of all PP implants placed by the 2 surgeons. The procedures for the primary surgery were 12 enucleations (67%), 5 eviscerations (28%), and 1 secondary implant (5%). Clinical findings included anterior implant exposure and discharge in all cases. Histopathologic analysis was performed in all of the implants and showed less than 50% fibrovascular ingrowth in 16 implants (89%) and predominantly acute or mixed inflammation in 15 (83%). Foreign body giant cells were seen adjacent to the implant material in all cases. Bacterial colonies on gram stain were identified in 12 specimens (67%); overall, gram-positive cocci in clusters or chains were found in 10 implants (56%), and gram-negative bacteria were found in 1 (5.5%). Thirteen patients (72%) lived in locations distant from Vancouver, the surgical center. This article presents the largest review of explanted porous polyethylene orbital spheres. The findings suggest that anterior exposure allows bacterial colonization and the development of a heavy inflammatory infiltrate. Poor tissue ingrowth may limit the penetration of topical or systemic antibiotic therapy, leading to the necessity for explantation. The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Effects and complications of placement of motility coupling post in porous polyethylene orbital implants

To investigate the effects and complications of primary and secondary placements of motility coupling post (MCP) in the unwrapped porous polyethylene orbital implant (PPOI) following enucleation. We investigated 198 patients who received PPOI implantation following the standard enucleation procedure in the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China, from 2002 to 2004. These patients were subgrouped into PPOI-only patients (112 cases, received PPOI following enucleation), primary MCP patients (46 cases, received primary placement of MCP during PPOI operation), and secondary MCP patients (40 cases, received secondary placement of MCP 6 months after the initial surgery). Effects and complications among these three groups were compared. The PPOI-only patients took shorter treatment course when compared with other two MCP groups (P<0.001), without significant difference noted between the two MCP groups. However, the two MCP groups had better prosthetic motility than PPOI-only group (P<0.001), without significant difference between the two MCP groups. In the early stage, 2 eyes in the PPOI-only group and 1 eye in the primary MCP group had PPOI infection. In PPOI-only group, 3 (2.68%) eyes had PPOI exposure, which occurred after fitting the prostheses; 4 eyes (8.70%) in primary MCP group and 1 eye (2.50%) in secondary MCP had PPOI exposure, which occurred before fitting the prostheses. After prosthesis was fit successfully, the excessive discharge and granuloma were 33.9% and 1.79% in PPOI group-only, 53.3% and 8.9% in primary MCP group, and 52.5% and 7.5% in secondary MCP group, respectively. Both primary and secondary placements of MCP into the PPOI following enucleation can help patients to obtain desirable prosthetic motility, but may be associated with more complications. The primary placement of MCP with skilled operation in selected patients is more recommendable than secondary placement.

The Role of Endothelial Progenital Cells and Fibrin on Vascularization and Stability in Orbital Implant

Purpose: The effects of endothelial progenitor cells (EPCs) and fibrin on fibrovascular growth into porous polyethylene orbital implants (Medpor® sheet) were investigated using stem cells. Methods: EPCs were separated from human adipose fat tissue for culture. Fluorescence-activated cell sorting (FACS) was used to identify the phenotype and to analyze the purity of EPCs cultivated from human adipose tissue. Processed Medpor® sheets were inserted in each quadrant of the subcutaneous fat layer under the dorsal surface of 20 anesthetized athymic nude mice, using sterile methods. Medpor® sheets processed with endothelial progenitor cells and fibrin were inserted into the two top quadrants, a Medpor® sheet processed with fibrin was inserted in the lower right quadrant, and an unprocessed Medpor® sheet was inserted in the lower left quadrant of each mouse. The mice were sacrificed on the seventh day. The adhesiveness and blood vessel formation were quantified by weight and the number of blood cells within the Medpor® sheets. Hematoxylin and eosin (H&E) and toluidine blue stains were used to analyze fibrovascular and cell growth within the Medpor® sheets. Results: The sheets processed with EPCs and fibrin were heavier and contained more white and red blood cells (p

Porous Polyethylene (Medpor) Orbital Implants with Primary Acellular Dermis Patch Grafts

Purpose: To evaluate the results of the porous polyethylene (Medpor) orbital implantation technique combined with the use of a primary patch graft of acellular dermis. Methods: The study design was a retrospective, non-comparative single surgeon case series of 27 patients. The Medpor orbital implant was placed with a primary anterior sub-Tenon's acellular dermis patch after evisceration (23/27), enucleation (2/27) or implant exchange/secondary implant procedure (2/27) over a period of 3 years. Risk factors for dehiscence/complications were defined as trauma, infection, inflammation, previous ocular surgery, radiotherapy, secondary orbital implantation, and removal of extruding implants. The primary outcome measure was the development of implant exposure. Other complications were also recorded, including postoperative conjunctival wound dehiscence. Results: Twenty-five patients (93%) had more than 2 risk factors. Mean follow-up time was 22 months (median 24 months, range 4–34 months). Three (11%) patients needed further intervention, which included pyogenic granuloma excision (1) and fornix formation (1). Conjunctival wound dehiscence followed by implant exposure occurred in 1 of 27 eyes (3.7%). The cosmetic appearance was satisfactory in 26/27 patients. Conclusions: Our results with primary acellular dermis grafts when coupled with Medpor orbital implantation are encouraging.