Late infection of hydroxyapatite orbital implants

BACKGROUND: Exposure and minor complications of hydroxyapatite orbital implants are common. Infection appears to be rare and fibrovascular ingrowth into hydroxyapatite implants may make infection and extrusion less likely than with other types of orbital implant. METHODS: We describe three cases of chronic low-grade infection of hydroxyapatite implants, occurring late after apparently uncomplicated surgery, with tiny or inapparent areas of conjunctival loss or exposure. RESULTS: Two of the three cases grew Staphylococcus oureus on culture. All three implants ultimately needed to be removed. A characteristic histological pattern was seen, with abrupt transition between vascularized and abscessed implant. CONCLUSIONS: Chronic infection of hydroxyapatite implants can occur late, in the absence of large conjunctival defects, or other obvious risk factors.While exposure of the implant to pathogens through a breach in the conjunctiva may have been a factor, it appeared that the infection may have arisen in an avascular portion of the implant prior to the conjunctival breakdown in one or more of these cases.     

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.     

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.     

Aspergillus mycetoma in a secondary hydroxyapatite orbital implant: a case report and literature review.

OBJECTIVE: The authors describe the first case report of a fungal abscess within a hydroxyapatite orbital implant in a patient who had undergone straightforward secondary hydroxyapatite implant surgery. DESIGN: Case report and literature review. INTERVENTION: Four months postoperatively after pegging and 17 months after original implant placement, chronic discharge and socket irritation became evident. Recurrent pyogenic granulomas were a problem, but no obvious area of dehiscence was present over the implant. The peg and sleeve were removed 31 months after pegging (44 months after original placement of the implant). The pain and discharge did not resolve, and the entire hydroxyapatite orbital implant was removed 45 months after sleeve placement and 58 months after initial implant placement. The pain and discharge settled rapidly. MAIN OUTCOME MEASURES: Cultures and histopathology. RESULTS: Results of bacterial cultures were negative. Results of histopathologic examination of the implant disclosed intertrabecular spaces with multiple clusters of organisms consistent with Aspergillus. CONCLUSIONS: Persistent orbital discomfort, discharge, and pyogenic granulomas after hydroxyapatite implantation should cause concern regarding potential implant infection. The authors have now shown that this implant infection could be bacterial or fungal in nature. This is essentially a new form of orbital Aspergillus, that of a chronic infection limited to a hydroxyapatite implant.     

Clinicopathologic analysis of 15 explanted hydroxyapatite implants

PURPOSE: To report the clinical findings, treatment, outcomes, and histopathologic findings in patients with suspected orbital implant infection requiring implant removal. METHODS: Retrospective, observational case series of 14 patients (15 hydroxyapatite orbital implants) undergoing implant removal from September 1994 through December 2002. Patient age, type of surgery, implant type, symptoms, treatment, histopathology of implant, and follow-up course were analyzed. RESULTS: Of the 14 patients, 7 were female and 7 were male. The mean age at explantation was 42 years. The most common symptoms were discharge and socket tenderness. The most common signs were conjunctival inflammation (edema, hyperemia), discharge, and recurrent pyogenic granuloma. Clinical evidence of infection was documented in 13 patients. Histopathologic assessment of the 15 explanted implants showed acute inflammation and necrosis (abscess) with identification of microorganisms (5 patients), acute inflammation and necrosis without identification of microorganisms (4 patients), chronic inflammation with identification of microorganisms (1 patient), chronic inflammation without identification of microorganisms (3 patients), and a predominant foreign body granulomatous response without identification of microorganisms (2 patients). Osseous metaplasia was seen in 10 implants. Prompt resolution of symptoms and signs occurred in all but one case. CONCLUSIONS: The clinical course of porous orbital implant infection may be prolonged, and the early symptom of recurrent discharge, a common problem for implant recipients, may delay diagnosis. Implant infection should be suspected when there is persistent conjunctival inflammation and discharge after implant placement despite antibiotic therapy, discomfort on implant palpation, and recurrent pyogenic granuloma (indicative of implant exposure). Implant removal is usually required in these cases. If orbital pain (not necessarily related to implant palpation) is the main complaint, without signs of conjunctival inflammation and with or without discharge, one should consider other reasons for the symptoms.     

Proliferation of human fibroblasts in vitro after exposure to orbital implants

BACKGROUND: Porous orbital implants allow fibrovascular ingrowth and integration with the extraocular muscles. The available implants have different structural characteristics, which may influence orbital response. We studied the proliferation of orbital fibroblasts in vitro after exposure to four different orbital implants. METHODS: Four orbital implant biomaterials were studied: hydroxyapatite (Bio-Eye), synthetic hydroxyapatite, porous polyethylene (Medpor) (pore sizes 150 microm and 400 microm) and aluminium oxide (Bioceramic implant). Human fibroblasts obtained from orbital fat at the time of elective blepharoplasty were cultured and then exposed to the individual implants. Cell growth was assessed with immunocytochemical analysis using bromodeoxyuridine, a thymidine analogue. After DNA denaturation, the cells were washed, incubated with secondary antibody and visualized. RESULTS: The fibroblasts growing on the Bio-Eye, synthetic hydroxyapatite, and 150-microm and 400-microm Medpor implants all had debris associated with them. The Bioceramic implant was free of this debris. The Bioceramic implant and the 150-microm Medpor implant had the greatest number of fibroblasts on the coverslips. INTERPRETATION: The proliferation of fibroblasts, as determined by visualization of actively dividing cells with bromodeoxyuridine, differed on the various implants studied. The lack of debris associated with the Bioceramic implant may be related to the crystalline structure of the implant.     

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.     

A case of orbital abscess following porous orbital implant infection

PURPOSE: We present a case of orbital abscess following porous orbital implant infection in a 73-year-old woman with rheumatoid arthritis. METHODS: Just one month after a seemingly uncomplicated enucleation and porous polyethylene (Medpor) orbital implant surgery, implant exposure developed with profuse pus discharge. The patient was unresponsive to implant removal and MRI confirmed the presence of an orbital pus pocket. Despite extirpation of the four rectus muscles, inflammatory granulation debridement and abscess drainage, another new pus pocket developed. RESULTS: After partial orbital exenteration, the wound finally healed well without any additional abscess formation. CONCLUSIONS: A patient who has risk factors for delayed wound healing must be examined thoroughly and extreme care such as exenteration must be taken if there is persistent infection.     

Wrapping hydroxyapatite orbital implants with posterior auricular muscle complex grafts

PURPOSE: To report the use of posterior auricular muscle complex grafts as a wrapping material for hydroxyapatite orbital implants in enucleation surgery. METHOD: In a retrospective multicenter study, autogenous posterior auricular muscle complex grafts were used to cover hydroxyapatite orbital implants in 83 patients with a mean age of 38.6 years (range, 1 to 85 years), of whom 63 had primary unilateral enucleation and 20 had secondary orbital implants following enucleation. The mean follow-up period after posterior auricular muscle complex grafts was 36 months (range, 14 to 60 months). RESULTS: Of the 83 patients, two (2.4%) developed limited orbital implant exposure, which was treated with a second posterior auricular muscle complex "patch graft." No patient developed postoperative orbital infection or implant extrusion. All patients were fitted with an acceptable prosthesis and had satisfactory cosmetic and functional results. No patient developed vascular compromise or a wound defect associated with the posterior auricular donor site. CONCLUSION: Autogenous posterior auricular muscle complex grafts should be considered as an appropriate wrapping material for hydroxyapatite orbital implants for primary enucleation and for secondary orbital implants after enucleation.     

Culture-proven Aspergillus fumigatus infection in a primary hydroxyapatite orbital implant

Hydroxyapatite orbital implants are widely used in enucleation surgery. Infection in this setting is an uncommon but severe complication. Herein a patient with a 3-year history of chronic socket discharge, orbital discomfort, conjunctival breakdown and implant exposure after enucleation and implantation of a hydroxyapatite sphere 7 years previously is reported. Repeated attempts at covering the exposed implant failed. Eventually the implant was removed, and Aspergillus fumigatus was cultured from the explanted material. This is the second reported case of Aspergillus infection of a hydroxyapatite orbital implant, and the first case where fungal cultures were positive.     

羟基磷灰石义眼台眶内植入术后结膜脓性肉芽肿形成的原因分析(英文)

目的:分析羟基磷灰石(hydroxyapatite,HA)义眼台眶内植入术后结膜脓性肉芽肿形成的原因。方法:回顾性分析我院眶内植入HA义眼台250例(钻孔及栓钉置入68例),随诊18mo~10a,脓性肉芽肿形成后首先药物保守治疗,无效后采用手术治疗。结果:植入HA义眼台250例中发生脓性肉芽肿10例,其中9例在钻孔及栓钉置入术4~7a后发生,1例发生时羟基磷灰石义眼台未钻孔。9例保守治疗效果均欠佳,行HA义眼台取出术,1例拒绝眼台取出而继续保守治疗。结论:脓性肉芽肿是严重的义眼台植入术后并发症,发生原因可能与义眼台植入后血管化不足,义眼台暴露与继发感染,异体材料包被,义眼台钻孔及栓钉置入等因素有关,而与栓钉的材料无关。脓性肉芽肿的发生意味着义眼台可能发生了感染,最终需行义眼台取出术。     

异形羟基磷灰石义眼台的临床应用

目的:观察异形羟基磷灰石义眼台植入术并发症及手术效果,探讨异形义眼台的适应证及其临床应用价值。方法:设计不同体积的异形羟基磷灰石义眼台,治疗眼球萎缩、眼内容物摘除及眼球摘除术后患者共30例。对照组植入常规圆球形羟基磷灰石义眼台共30例。异形义眼台组与对照组间性别、年龄、眼部情况相似。手术后随访时间6mo以上,观察患者义眼台植入术后球结膜愈合时间、义眼台暴露、感染等并发症、义眼台活动度、位置以及与义眼片适合程度的差异。结果:异形羟基磷灰石义眼台组没有发生义眼台暴露、感染等严重并发症,球结膜愈合时间短,义眼台植入后前表面呈圆弧形,能与义眼片很好的吻合,义眼台活动度及位置均好于对照组。对照组有2例(7%)发生早期球结膜裂开的并发症,经过治疗后均愈合。结论:异形义眼台可以降低义眼台植入后引起的并发症,可以有效适应患者眼部病变的情况,获得良好的手术效果,适应证更广,安全性更好。     

Bovine pericardium as a wrapping for orbital implants

PURPOSE: We report the use of bovine pericardium as an alternative wrapping for porous orbital implants after enucleation. METHODS: We retrospectively reviewed the records of all patients who received a bovine pericardium-wrapped orbital implant after enucleation by the authors between August 1, 1996, and December 1, 1999. RESULTS: Eighty patients underwent placement of bovine pericardium-wrapped orbital implants. The average age at the time of implantation was 49.3 years (range, 5 years to 83 years). The mean follow-up interval was 11.8 months (range, 2 to 41 months). There were no intraoperative complications. No patient had secondary systemic infection or showed evidence of rejection. There was no clinical evidence to suggest that vascularization of the porous implant was unusually delayed, and there were no complications after secondary drilling and placement of a coupling post. Four (5%) of 80 patients had complications requiring removal of the spherical implant. All 4 patients had hydroxyapatite implants. Two patients had significant exposure requiring removal of the implant at 2 months after surgery; 1 patient had a chronic fistulous tract with secondary infection 3 years after surgery: and 1 patient had chronic orbital pain requiring removal of the implant at 1 year after surgery. CONCLUSIONS: The incidence of implant exposure was less than 4%. This compares favorably to the incidence of exposure of 9% to 21% reported in recent literature. Other complications were few and of minimal clinical significance. The authors conclude that bovine pericardium is a viable option to sclera as a wrapping for porous orbital implants.     

Comparison of vascularization of Medpor and Medpor-Plus orbital implants: a prospective, randomized study

PURPOSE: To compare vascularization of porous polyethylene (Medpor) and porous polyethylene with synthetic bone graft particulate (Medpor-Plus) orbital implants following enucleation. METHODS: Prospective, randomized study involving 10 patients. A standard enucleation procedure was performed, and each patient was randomized to receive either Medpor or Medpor-Plus orbital implant with anterior scleral cap technique. Gadolinium-enhanced, 3-Tesla MRI was performed at 1.5 months, 3 months, and 4.5 months following surgery. Implant vascularization was calculated in axial, coronal, and sagittal planes with manual planimetric method using postcontrast T1-weighted Digital Imaging and Communications in Medicine images. RESULTS: The mean area of implant vascularization at 1.5 months, 3 months, and 4.5 months for Medpor implants was 58%, 70%, and 75%, respectively, and for Medpor-Plus implants was 69%, 76%, and 85%, respectively. The mean vascularization of Medpor-Plus implants was more than Medpor implants at 1.5 months (p = 0.008), 3 months (p = 0.09), and 4.5 months (p = 0.003). The difference between the 2 groups assessed by repeated measures analysis of variance was statistically significant (p < 0.0001). During the mean follow-up of 36.7 months (range, 18-43 months), 1 patient in the Medpor group had implant exposure that responded to scleral patch graft. CONCLUSIONS: Implant vascularization is faster with Medpor-Plus implants compared with Medpor implants when assessed by a planimetric method using 3 Tesla MRI. The addition of synthetic bone graft particulate (Novabone) to porous polyethylene may enhance implant vascularization.     

The survival of freely grafted orbital fat on porous polyethylene orbital implants in the rabbit

PURPOSE: To investigate the long term survival of orbital fat grafted on a Medpor implant as a method of preventing porous polyethylene orbital implant (Medpor) exposure in anophthalmic sockets. METHODS: In one orbit in each of 8 rabbits, a small amount of retrobulbar orbital fat was grafted between the anterior surface of the Medpor implant and overlying conjunctiva, during the enucleation and Medpor implantation procedure. Two rabbits were sacrificed at 2, 4, 8 and 12 weeks postoperatively and grafted orbital fats were examined by light microscopy. RESULTS: Grafted orbital fat was well-maintained at 2 and 4 weeks, postoperatively. However, fat amounts were significantly reduced at 8 weeks, and viable fat was barely visible at 12 weeks. CONCLUSIONS: In rabbits, orbital fat grafted on Medpor implants was gradually resorbed, and the fat-occupied volume was not maintained.     

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.     

The bioceramic orbital implant: experience with 107 implants

PURPOSE: To assess the problems associated with the Bioceramic (Aluminum oxide, Al(2)O(3)) orbital implant. METHODS: A consecutive case series of 107 patients receiving a Bioceramic orbital implant by two surgeons over a 3-year period were reviewed. The authors analyzed patient age, type of surgery, size of implant, peg system, follow-up duration, time of pegging, complications encountered, and treatment. RESULTS: Seven patients were lost to follow-up after 2 months, leaving 100 patients who were followed from 3 to 38 months (average, 13.4 months). Three patients died during the follow-up period (one with 2 months' follow-up, one with 7 months' follow-up, and the third with 9 months' follow-up). Implant-related problems occurred in 11 (11%) patients. Discharge occurred in 5 (5%) patients, implant exposure in 2 (2%), socket discomfort in 1 (1%), trochleitis in 1 (1%), and conjunctival thinning in 2 (2%). Peg problems occurred in 11 (34.3%) of 32 pegged patients: discharge in 4 (12.5%) and in 1 patient (3.1%) each, pyogenic granuloma, conjunctiva overgrowing the peg, implant exposure around the sleeve, clicking, accumulation of black material, and broken peg during insertion. Infection did not occur in any patient. CONCLUSIONS: The Bioceramic orbital implant represents an alternative porous orbital implant that is biocompatible with orbital tissues, easy to manufacture, structurally strong, and less expensive than other commercially available porous orbital implants (e.g., Bio-Eye hydroxyapatite implant). Problems encountered with its use are similar to those seen with the Bio-Eye orbital implants but appear to occur less often. The incidence of exposure associated with the Bioceramic implant is less than that reported for the Bio-Eye.     

Oculoplastic and orbital applications of porous high-density polyethylene implants

Porous high-density polyethylene implants have become well accepted for the repair of orbital wall fractures, delayed orbital reconstruction, orbital rim and malar bony onlay augmentation, and volume replacement as orbital spherical implants for the treatment of anophthalmos. Medpor (Porex Surgical, Inc. College Park, GA) is a commercially available porous high-density polyethylene product available in sheets, blocks, Flexblocks, several onlay contour shapes, spheres, and custom implants. Recently, the motility coupling post was introduced to provide an integrated Medpor spherical implant with enhanced prosthetic motility. Medpor implants possess several advantages over hydroxyapatite implants.     

MEDPOR在眼及眶部整形中的应用

目的：研究MEDPOR在眼部及眶部整形美容中的应用。方法：应用MEDPOR治疗36例（36眼）眼部及眶部整形患者。结果：术后所有患者效果满意，眼球正位，复视消失，一例眶修复术后，又经两次斜视手术，复视得到矫正。结论：在眼部及眶部整形美容术中，MEDPOR是一种良好的，现代的线状高密度多孔网状生物材料。     

Safety of unwrapped spherical orbital implants

PURPOSE: To determine the exposure rate of unwrapped spherical orbital implants after enucleation surgery. METHODS: Retrospective review of consecutive case series. All patients undergoing orbital implantation during enucleation surgery from October 1999 to September 2003 were included. Charts were reviewed for preoperative diagnoses, type and size of implant, use of a wrapping material, and complications. RESULTS: Twenty-six consecutive patients underwent enucleation surgery without wrapping material. Nineteen patients received porous polyethylene, 5 patients received polymethylmethacrylate, and 2 received hydroxyapatite. Mean implant diameter was 21.03 mm. Mean follow-up was 17.1 months (range, 2 to 43 months). There were no complications of implant extrusion, exposure, infection, or migration. CONCLUSIONS: The use of unwrapped spherical orbital implants may be associated with a low rate of early exposure. Careful choice of implant type may help reduce the risk of implant exposure.