The bioceramic orbital implant: a new generation of porous implants

PURPOSE: The authors describe a new generation of porous orbital implant made of aluminum oxide (Al2O3) and compare it with the hydroxyapatite orbital implants (Bio-Eye and FCI hydroxyapatite). METHODS: The authors examined the new implant macroscopically, with chemical analysis and microscopically with scanning electron microscopy. Animal implantation studies were performed using six adult male New Zealand albino rabbits. Implant vascularization was evaluated by means of magnetic resonance imaging and histopathologic sectioning. RESULTS: The Bioceramic orbital implant was found to have very uniform pore structure with an average pore size of 500 microm. The implant was 99.9% aluminum oxide on x-ray diffraction. Magnetic resonance imaging in vivo vascularization studies demonstrated enhancement of the implant to its center by 4 weeks after implantation in the rabbit. Histopathologically, fibrovascularization occurred uniformly throughout the implant and was noted by 4 weeks. CONCLUSIONS: The Bioceramic orbital implant represents a new porous orbital implant that has a very regular and extensive interconnected pore system, is as biocompatible as hydroxyapatite, is easy to manufacture, structurally strong, and free of contaminants. It is manufactured with no disruption to marine life ecosystems as may occur in the harvesting of coral for other orbital implants. It is less expensive than currently available hydroxyapatite implants and was approved by the U.S. Food and Drug Administration in April 2000.     

Primary placement of a hydroxyapatite-coated sleeve in bioceramic orbital implants

PURPOSE: To study a new surgical option of primary placement of a hydroxyapatite-coated sleeve into the Bioceramic implant during enucleation or evisceration. DESIGN: Retrospective, observational case series. METHODS: A standard enucleation or evisceration was performed, followed by the preplacement of a hydroxyapatite-coated sleeve into the Bioceramic implant. Care must be taken to ensure the sleeve has been positioned centrally when the implant is put inside the orbital socket. Complications such as sleeve exposure, Bioceramic implant exposure, and infection were closely observed. RESULTS: Twenty-seven patients were treated in above fashion with five enucleation and 22 evisceration procedures. Five of the sleeves have exposed spontaneously during 1 to 4 months after original surgery. They had no further complication, except for one sleeve around which there were visible Bioceramic spicules attributable to long-term corticosteroid usage. The remaining 22 sleeves that did not spontaneously expose pursued secondary exposure of the sleeve and peg insertion by the conjunctival cutdown procedure 3 months postoperatively. One sleeve was medially positioned far away from the implant center. Re-insertion of new sleeve and peg was scheduled 2 weeks later. One additional sleeve was obliquely positioned after conjunctival cutdown procedure. Fortunately, all 27 patients were successfully fitted with a peg-coupled prosthesis with good motility. CONCLUSIONS: Primary placement of a hydroxyapatite-coated sleeve into the Bioceramic implants has several advantages, including high patient acceptance, technical simplicity, and an office-based conjunctival cutdown pegging procedure. By avoiding the expense of postoperative imaging studies and additional prosthetic modification, a more rapid and efficient rehabilitation is possible.     

羟基磷灰石义眼座Ⅱ期植入术中寻找眼外肌的手术体会

目的探讨羟基磷灰石（HA）义眼座Ⅱ期植入术中寻找眼外肌的方法,以减少并发症的发生。方法选择近5年来我科住院行HA义眼座Ⅱ期植入的其中73例（73只眼）患者,年龄5—74岁,男性多于女性,病因多样,以眼外伤最多见。手术方法：运用肌鞘-直肌法在内、外、上、下四个方位内寻找4直肌,选择相应大小的HA义眼座植入肌锥腔内,将4直肌固定于眼座表面,分层严密缝合筋膜组织、结膜。结果73例中有62例的四条眼外肌都可找到,其中包括视网膜母细胞瘤眼球摘除术后合并放疗的、眼座取出需再植入的、合并眶骨折的。其余11例中有3例视网膜母细胞瘤眼球摘除术后合并放疗的患眼找到3条直肌,2例眼座取出需再植入者找到2条直肌,5例严重眼外伤的找到3条直肌,仅1例患者只找到1条确切的直肌。植入后无1例发生眼座暴露,术后有5例发生上睑下垂,可能在寻找上直肌时损伤了提上睑肌所致,已通过手术予以矫正。结论循着肌鞘寻找眼外肌的方法不仅提高了手术成功率、减少了术后并发症的发生,而且防止了眼座的前移。此法适用于各种状况下的Ⅱ期眼座植入术。     

Coralline hydroxyapatite orbital implant (bio-eye): experience with 158 patients

PURPOSE: To assess the problems seen in 158 patients with coralline hydroxyapatite (HA) orbital implants (Bio-Eye). METHODS: A consecutive case series of 170 patients receiving coralline HA implanted by two surgeons over a 5-year period were reviewed. The authors analyzed age, type of surgery, implant size, peg system, follow-up duration, time of pegging, problems encountered, and treatment. RESULTS: Twelve patients were lost to follow-up after 5 months, leaving 158 patients who were followed from 6 to 130 months (average, 39 months). Problems in unpegged implants occurred in 36 (22.8%) patients. Discharge occurred in 18 (11.4%) patients, implant exposure in 12 (7.6%), socket discomfort in 1 (0.6%), conjunctival thinning in 3 (1.9%), chronic conjunctival swelling in 2 (1.3%), and implant infection in 3 (1.9%). Problems after pegging occurred in 68 (50.7%) of 134 patients: discharge in 27 (20.1%), pyogenic granuloma in 24 (17.9%), conjunctiva overgrowing the peg in 4 (3.0%), implant exposure around the sleeve in 5 (3.7%), clicking in 6 (4.5%), peg on an angle in 2 (1.5%), loose sleeve in 1 (0.7%), peg falling out in 18 (13.4%), popping peg in 1 (0.7%), poor transfer of movement in 3 (2.2%), pain with movement in 1 (0.7%), and implant infection in 2 (1.5%). CONCLUSIONS: The Bio-Eye orbital implant represents a porous orbital implant that is biocompatible with orbital tissues and allows fibrovascular ingrowth and improved motility when coupled to the overlying artificial eye. It is more expensive than other commercially available porous orbital implants, such as synthetic FCI3 HA, porous polyethylene (Medpor), and aluminum oxide (Bioceramic) implant. Problems encountered with its use are similar to those problems seen in patients with the synthetic FCI3 hydroxyapatite and aluminum oxide orbital implants.     

Problems after evisceration surgery with porous orbital implants: experience with 86 patients

PURPOSE: To assess the problems associated with the use of 4 types of porous orbital implant (Bio-Eye coralline hydroxyapatite, FCI3 synthetic hydroxyapatite, aluminium oxide [Bioceramic], and porous polyethylene [Medpor]) after evisceration surgery. METHODS: A retrospective analysis was made of all cases of evisceration with placement of one of four types of porous orbital implants performed between 1991 and 2002 by one surgeon (n = 86). Patient age, implant type and size, surgery type (standard evisceration or evisceration with posterior sclerotomies), peg system used, follow-up duration, time of pegging, problems before and after pegging, and treatment were recorded. RESULTS: Eight patients had less than 6 months of follow-up. The other 78 patients were followed for 6 to 107 months (average, 31 months). The following problems were noted before peg placement: discharge, 8 patients (10.2%); implant exposure, 6 patients (7.7%); implant fracture at the time of surgery, 1 patient (1.3%); persistent pain, 1 patient (1.3%). Of the 29 patients who had pegging, problems including discharge, exposure, pyogenic granuloma, infection, and peg sleeve problems occurred in 23 (79.3%). Sixteen (55.2%) of the 29 patients required at least 1 additional surgical procedure, 4 required 3 additional procedures, and 2 required 5 additional procedures, including implant removal. CONCLUSIONS: Although primary evisceration with posterior sclerotomies and placement of a porous orbital implant is an accepted technique for treating a variety of end-stage eye diseases, patients should be cautioned about an increased likelihood of problems and potential need for additional surgeries if pegging is considered.     

Treatment of prominent eyes with orbital rim onlay implants: four-year experience

PURPOSE: Different approaches have been proposed to address the aesthetic or reconstructive challenge associated with relatively prominent eyes. Operations that address the soft tissues alone are prone to failure if the underlying orbital bony relationships are not addressed. Orbital rim advancement can serve as a supplement to orbital decompression in this setting or as an alternative for patients who may not maximally benefit from decompression surgery. METHODS: We report our 4-year experience with porous polyethylene orbital rim onlay grafts used to address relative proptosis in 24 patients. RESULTS: All patients had some degree of subjective and objective improvement. Proptosis decreased an average of 4.65 mm, with a range of 3 to 9 mm, based on single-observer Hertel exophthalmometry measurements (5.2 mm in those with concomitant decompression). Lagophthalmos was also improved in all patients with preoperative inadequacy in eyelid closure. Interpalpebral fissure size was reduced 1.3 mm on average, with a range of 0.5 to 6 mm (2 mm in those with concomitant decompression). Average follow-up was 41 months, with a range of 7 to 70 months. In 3 cases, we noted postoperative lower eyelid retraction with eyelid adhesion to the implant; possible risk factors for this complication included reoperative cases and simultaneous eyelid reconstruction with hard palate grafts. CONCLUSIONS: The porous polyethylene orbital rim onlay implant offers a relatively simple and effective surgical technique for the treatment of symptomatic relative proptosis. It can be used alone or in combination with other techniques including midface lift, lower eyelid retractor recession, and orbital decompression. To be effective, the implant should be placed so that it is flush with or overlapping the orbital rim; lateral displacement negates the effect of the implant in improving the eyelid/globe relationship. Postoperative eyelid retraction with tethering to the implant is a potential risk of the onlay implant, and although it may not be possible to avoid this in all cases, surgeries should be designed to minimize postoperative eyelid retraction.     

Problems with the hydroxyapatite orbital implant: experience with 250 consecutive cases.

The coral derived hydroxyapatite sphere is a popular, integrated orbital implant designed to provide improved motility of the ocular prosthesis following enucleation. Although the implant has rapidly become widely used by ophthalmologists, little information is available regarding the problems of this technique in a large series of cases. Experience with 250 consecutive cases of hydroxyapatite orbital implant use was reviewed and the problems of the implants and their management investigated specifically. The reasons for enucleation included uveal melanoma (157 cases), retinoblastoma (70 cases), blind painful eye (22 cases), and intraocular medulloepithelioma (one case). Earlier treatment to the eye was performed before enucleation in 47 cases and included repair of ruptured globe (17 cases), plaque radiotherapy (18 cases), external beam radiotherapy (six cases), and others (six cases). During a mean of 23 months' follow up (range 6-40 months), there have been no recognisable cases of orbital haemorrhage related to the implant, and no cases of implant extrusion or implant migration. There was one case of presumed orbital infection (culture negative) that resolved with intravenous antibiotics and the implant was retained within the orbit. Other problems included conjunctival thinning in eight cases managed by observation and prosthesis adjustment, and conjunctival erosion in four cases managed by combinations of scleral patch graft, conjunctival flap, and prosthesis adjustment. The conjunctival erosion was caused by a poorly fitting prosthesis in three cases and wound dehiscence in one case. The problem rate in eyes receiving prior radiotherapy or surgery was not increased. The hydroxyapatite integrated orbital implant is a well tolerated motility implant without the high rate of extrusion and infection seen with other motility implants. The prosthesis fit may contribute to the tolerance of the implant.     

Enucleation with unwrapped porous and nonporous orbital implants: a 15-year experience

PURPOSE: To compare the rates of implant exposure and implant migration among patients who received an unwrapped nonporous spherical implant versus an unwrapped porous spherical implant immediately after enucleation. METHODS: Retrospective analysis of a series of 258 patients who received either an unwrapped nonporous spherical implant (n = 68) or an unwrapped porous spherical implant (n = 190). Actuarial rates of migration of the implant and conjunctival dehiscence leading to implant exposure were computed. RESULTS: Sixty-eight patients received an unwrapped nonporous implant (polymethylacrylate [PMMA]) and 190 patients received an unwrapped porous implant (139 hydroxyapatite [HA] and 51 porous polyethylene [Medpor]). Median follow-up duration in this study was 37.6 months. Implant exposure occurred in 1 of the 68 nonporous implant cases (1.5%) and in 4 of the 190 porous implant cases (2.1%). This difference is not statistically significant (P = 0.85). In contrast, clinically significant implant migration occurred substantially more frequently in the patients who received a nonporous implant. The cumulative actuarial probability of implant migration at 60 months was 15.5% for the nonporous implants versus 0.7% for the porous implants. This difference was statistically significant (P = 0.0003). CONCLUSIONS: Orbital implant migration occurred in a significantly greater proportion of patients who received a nonporous implant than in those who received a porous implant. Implant exposure occurred at a low rate that was not significantly different in the two subgroups.     

The domed dermis-fat graft orbital implant

Dermis-fat grafts have been widely used in the reconstruction of the anophthalmic socket, both primarily after enucleation and secondarily after extrusion or migration of an existing implant. The dermis-fat graft is an effective means of replacing orbital volume and affording motility of the ocular prosthesis with both low morbidity and a satisfactory cosmetic result. We present a modification to the dermis-fat graft technique. Our modification creates a domed shape to the anterior surface of the graft that simulates the curvature of the eye. The dome-shaped graft creates deeper fornices than a standard flat-surfaced dermis-fat graft. It also allows better contact between the prosthesis and the dermis as the graft moves. The prosthesis can be thinner centrally and lighter than a prosthesis fabricated for a socket with a standard dermis-fat graft or spherical implant. This results in better motility of the prosthesis while also replacing orbital volume. There is no additional morbidity associated with this technique. We have used this procedure successfully in 18 patients; 10 were primary grafts and eight secondary grafts. Motility of the prosthesis was satisfactory in all cases. There was no abnormal graft shrinkage. All grafts maintained their domed shape. Follow-up ranged from 6 to 21 months.     

The quasi-integrated porous polyethylene orbital implant

PURPOSE: To describe a new quasi-integrated porous polyethylene orbital implant that combines the advantages of host tissue incorporation and improved motility with a single-stage surgery. METHODS: Twenty-four consecutive patients undergoing primary or secondary orbital implantation received the quasi-integrated porous polyethylene implant. Approximately 6 weeks after implantation, a custom-fitted prosthesis was made by an impression technique to provide a "lock-and-key" fit with the orbital implant. Postoperative complications and motility of the prosthetic shell were evaluated. RESULTS: During the 27-month period between December 1998 and March 2001, 24 patients received the quasi-integrated porous polyethylene implant as a buried orbital implant. Thirteen patients received the implant as a primary orbital implant after either evisceration or enucleation and 11 patients received the implant as a secondary orbital implant. Follow-up ranged from 3 months to 30 months, with an average of 16.9 months. All patients were considered to have good motility of their prosthetic shell at their final follow-up visit. No cases of implant extrusion or migration were noted. Two patients required deepening of their inferior fornix to accommodate the increased motility of their prosthesis. CONCLUSIONS: The new quasi-integrated porous polyethylene orbital implant provides improved motility without the need for secondary placement of pegs or screws. It has the advantage of biocompatibility, allowing host tissue incorporation to resist implant migration and extrusion. The implant is available in three sizes: small, medium, and large, approximating the volume of a 16-, 18-, and 20-millimeter sphere, respectively.     

Experience with scleral covered orbital implants

The scleral covered implant provides excellent and lasting volume replacement and is retained well as a secondary implant. It should be avoided if the fornices are shallow and as a primary implant after recent ocular trauma.     

One‐stage explant–implant procedure of exposed porous orbital implants

Purpose: To investigate the risks of implant exposure after a combined explant–implant procedure in patients with an exposed porous orbital implant. Methods: Twenty‐four consecutive patients who had a combined explant–implant procedure of an exposed hydroxyapatite (21) or porous polyethylene (3) orbital implant from January 2000 to February 2009 were included. The patient records were reviewed; patients were interviewed by telephone and invited for a clinical examination. Histopathological examination was carried out on the removed implants. Main outcome measures were: presence of exposure of the new implant or not, patient graded satisfaction with the cosmetic result, and presence of poor motility. Results: None of the new implants became exposed or infected in the follow‐up period of 25 [3–94] months (median [range]). The patients scored their satisfaction with the cosmetic result to a median score of 9 (range 5–10). Poor motility was present in six of 17 patients. Micro‐organisms were identified in three removed implants and signs of inflammation were present in 20 removed implants. Conclusions: If a decision of implant removal has been made, it is safe to replace the implant at the same procedure in sockets without profound signs of infection. The procedure carries a possible risk of poor motility.     

Hydroxyapatite orbital implants Experience with 100 cases

Background: The hydroxyapatite (HA) intraorbital implant is a relatively new implant made from the porous skeleton of a coral species which allows fibrovascular ingrowth and therefore tissue integration. After fibrovascular ingrowth, a hole can be drilled in the implant and a motility peg inserted to increase movements of the prosthesis by coupling the implant to the prosthesis. Method: The records of the first 100 cases of HA intraorbital implants inserted by the one surgeon were analysed for complications, pain and nausea postoperatively, length of hospital stay, and further surgical procedures required. A series of acrylic implants inserted by the same surgeon was used for comparison. Results: Twenty-five primary and 75 secondary HA implants were performed in patients ranging from six to 74 years of age. All were covered in donor sclera. Follow-up was three to 34 months (mean 16.9, median 17.0). Complications occurred in 15 patients and included too large an implant (seven cases) requiring surgical reduction, scleral exposure in three (repair required in one), an early small exposure of the coral in one case, late thinning of the conjunctiva and later exposure of the implant in one, and shallowing of the inferior fornix requiring mucous membrane grafting in three. No implants migrated, extruded or became infected. Of 80 patients beyond six months follow-up, 28 (35%) had insertion of motility pegs, and six (7.5%) of these suffered minor complications related to the peg. Compared to patients having acrylic implants, the postoperative analgesic requirements and length of hospital stay were significantly greater for the HA patients. Conclusions: Hydroxyapatite intraorbital implants represent a significant advance over other implants and offer a more stable, safe alternative. They also offer the possibility of improved prosthesis motility. The additional cost of the implant, prolonged hospital stay and postoperative pain, should be considered in recommending such implants to patients either as primary or secondary implants.