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(R)) soaked with Nepidermin (Easyef(R)), Trafermin (Fiblast(R)), 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(R)-, Fiblast(R)- and normal saline-soaked groups. The degree of fibrovascularization was higher in the Easyef(R)-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(R)-, and Fiblast(R)-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.

Expanded Polytetrafluoroethylene as a Wrapping Material for Porous Polyethylene Orbital Implant

PURPOSE: To investigate the possibility of expanded polytetrafluoroethylene (e-PTFE) as a wrapping material for porous polyethylene orbital implant. METHODS: Two groups of 6 female New Zealand albino rabbits underwent enucleation with placement of a 12 mm porous polyethylene orbital implant wrapped in simple e-PTFE in one group (group 1) and macro-porous e-PTFE in the other group (group 2). Histopathologic sections of the implants obtained at 4, 6, 8 weeks were compared on the extent of fibrovascular ingrowth, percentage of the area of proliferated vessel, and grade of fibrosis between the two groups. RESULTS: There was no implant exposure or severe inflammation in group 1 and 2 during the observation. The extent of fibrovascular ingrowth differs only at 4 weeks. Group 1 showed less fibrovascular ingrowth (until outer 1/3) at anterior half compared with posterior one, but there was no difference between anterior and posterior half in group 2 (until middle 1/3). The percentage of the area of the proliferated vessels was higher in group 2 than group 1 at both anterior and posterior half, and the anterior/posterior ratio of the area of vessels was also higher in group 2 than group 1. The grade of fibrosis was higher in group 2 than group 1 at 4, 6, and 8 weeks. CONCLUSIONS: Macro-porous e-PTFE almost didn't disturb fibrovascular ingrowth into the orbital implant, so macro-porous e-PTFE can be used safely as a wrapping material for porous polyethylene orbital implant.

Evisceration Using Scleral Capping Technique for Severe Phthisis Bulbi

PURPOSE: To introduce a new technique, involving the creation of a circumferential 360 degrees scleral relaxing incision, using an implant as large as 20 mm in diameter, and report on the surgical results in the treatment of severe phthisis bulbi, which are not indicated for classic evisceration. METHODS: The medical records of 20 patients with 20 phthisis bulbi who had undergone evisceration and placement, using the scleral capping technique, of porous polyethylene orbital implants as large as 20 mm in diameter between September 2002 and February 2006 were reviewed. For each patient, after evisceration, a circumferential 360 degrees equatorial scleral relaxing incision was made posterior to insertion of 4-recti muscles, and a porous polyethylene orbital implant was implanted. Each circumferential scleral relaxing incision wound was loosely sutured in the mattress fashion, using 5-0 braided polyester (Ethibond). RESULTS: The average of preoperative axial length, obtained using A scan and orbital computed tomography scan, was 16.8 mm. Orbital implants of 20 mm in diameter were implanted in all patients. The average of postoperative follow-up interval was 29.1 months. Orbital implant showed good motility to the satisfaction of all of patients. And the scleral capping technique could prevent complications, such as exposure of orbital implant, enophthalmos, and superior sulcus deformity. CONCLUSIONS: Scleral capping technique is safe and useful for evisceration in patients with severe phthisis bulbi. This technique can provide adequate space for the placement of and implant as large as 20 mm in diameter without generating any tension on wound. Consequently, this technique provided cosmesis and prosthesis motiliy, even without the use of a Medor coupling peg, with which patients were satisfied.

Effect of Basic Fibroblast Growth Factor on Fibrovascular Ingrowth into Porous Polyethylene Anophthalmic Socket Implants

To investigate the effect of basic Fibroblast Growth Factor (bFGF) on fibrovascular ingrowth into porous polyethylene orbital implants (Medpor (R) ) and to investigate any differences according to the method of administration. For the treated groups, after evisceration and Medpor (R) implantation, bFGF was administered by soaking Medpor (R) in the bFGF solution, and/or by injecting bFGF into the Medpor (R) 1 week after the operation. Implants were removed 4 weeks after the operation and examined for the degrees of fibrovascular ingrowth by light microscopy. The percentages of the cross-sectional area of the implant occupied by fibrovascular ingrowth and the numbers of proliferated vessels were significantly higher in the bFGF-treated groups (Mann Whitney test, p 0.05). bFGF promoted fibrovascular ingrowth into porous polyethylene orbital implants regardless of the route of administration. Therefore, bFGF might be helpful to prevent complications such as implant exposure.

The Effect of the Synthetic Bone Glass on the Fibrovascularization into Porous Polyethylene Orbital Implant

PURPOSE: To evaluate the effect of the synthetic bone glass particulate (BG) on the fibrovascular ingrowth into porous polyethylene orbital implant (PP). METHODS: Forty eight rabbits were divided into 4 groups according to the surgical techniques and implanted materials. One eye was enucleated one eye and PP was implanted in group 1, was eviscerated and PP was implanted in group 2, was enucleated and BG, containing 30% by weight synthetic bone glass particulate, was implanted in group 3, and was eviscerated and BG was implanted in group 4. All implants of each group were assessed by histologic study at the first, second, fourth, and eighth weeks postoperatively. The area of fibrovascular ingrowth was calculated by histologic examination. RESULTS: There were no statistically significant differences in the fibrovascular ingrowth among these groups. A greater number of vessels per unit area and matured fibrous tissue was found in the more outer zone at longer time after implantation, but there was not statistically significant difference among the four groups. CONCLUSIONS: On the basis of this study, the synthetic bone glass particulate did not significantly increase the rate of fibrovascular ingrowth into porous polyethylene orbital implant in rabbits.

Scleral Eversion Technique for Porous Polyethylene Orbital Implant after Evisceration

PURPOSE: This study is to describe scleral eversion technique as a modification of evisceration to improve its disadvantages for placement of porous orbital implant and to report the results of placement of porous orbital implants with this technique. METHODS: The medical records of 27 patients with 27 eyes who had undergone evisceration and placement of porous polyethylene orbital implant with scleral eversion technique between November 1998 and January 2000 were reviewed. Surgical technique involved the removal of corneal button and the intraocular contents. Optic nerve was severed, scleral shell was everted, and porous polyethylene orbital implant was implanted into the retroscleral and intraconal space. RESULTS: Orbital implants of 20 mm in diameter were implanted in all patients. The average postoperative follow-up interval was 22.4 months. No patient experienced severe complications like exposure of implant. All of patients showed good motility of orbital implant and 19 patients were satisfied with motility of prosthesis. Eight patients (29.6%) got placement of motility coupling post without significant problems to enhance motility. CONCLUSIONS: Scleral eversion technique is safe and useful for evisceration and placement of porous polyethylene orbital implant. This technique can provide adequate space for adequate size of implant without any tension on wound, thick anterior scleral barrier for implant and more vascular source for fibrovascular ingrowth. Therefore, it decrease exposure rate of implant.

Clinical Results of Porous Polyethylene Orbital Implants in Postenucleation Retinoblastoma Patients

PURPOSE: To report the clinical results of implantation of porous polyethylene orbital implant (Medpor(R))after enucleation of eyes in patients with retinoblastoma. METHODS: The medical records of 33 children who had undergone Medpor(R) implantation after enucleation of eyes in patients with retinoblastoma were reviewed retrospectively. RESULTS: Surgery was performed in 33 eyes of 33 patients. The mean age at the time of operation was 24 months (ranged from 2 to 85 months). The mean follow-up period was 20 months (ranged from 12 to 31months). The diameters of the orbital implant used were 18 mm in 20 patients, and 20 mm in 13 patients. All parents were satisfied with the motility and cosmesis of the prosthesis. Exposure of the porous polyethylene orbital implant was found in 11 eyes (33.3%) at the mean postoperative time of 15 months (ranged from 7 to 29 months). The implant exposures in 10 eyes were not responsive to supportive therapy and underwent subconjunctival scleral patch grafts and direct conjunctival closure with success. The small exposure of the remaining eye was spontaneously healed under a careful observation with supportive therapy. CONCLUSIONS: Medpor(R) implantation in children with retinoblastoma showed good surgical results. However, careful follow-up examination is needed due to potential conjunctival pressure erosion and implant exposure. If exposure of the implant does occur, active surgical management is suggested instead of supportive management.