Late porous polyethylene implant exposure after motility coupling post placement

Risk factors for orbital implant exposure after evisceration: A case control study of 93 patients

Purpose:

The study aims to analyze risk factors for exposure of orbital implants after evisceration by comparison of patients with and without exposure of implants.

Methods:

This is a case control study in retrospective interventional case series; Group A- implant exposures after evisceration, Group B - Patients on follow up after evisceration with implant, without exposure, with matched duration of follow up. The sample size is calculated for a power of 80.

Results:

Group A comprised 32 sockets with implant exposure, presenting at median 18 months after surgery; Group B included 61 eviscerated sockets, without implant exposure, with follow up median 36 months. Odds Ratio (OR) was calculated; infected eyes -OR 1.3, P = 0.6; phthisical eye - OR 1.4, P = 0.43; multiple prior surgeries- OR 1.55, P = 0.33. Group A had 59.3% porous implants, Group B 55.7%, - OR 1.3, P = 0.5. Mean implant size in Group A 19.06 mm, Group B 18.78 mm- showed no statistical difference. Multiple logistic regression analysis showed no significant risk factor for exposure. Surgeon factor was not analyzed since there were multiple surgeons.

Conclusion:

This is the first study with calculated sample size, comparing implant exposure patients to a control group. Porous implant material, presence of infection, phthisical scleral shell, and prior surgery showed higher trend of exposure (Odds ratio >1), but none was conclusive. Larger size of implant was not a risk factor for exposure. Eliminating the role of several factors in implant exposure allows the surgeon to make better surgical choices: such as place an implant of appropriate size, of a material of surgeon's choice, and do primary placement of implant in a patient with evisceration post-corneal ulcer or endophthalmitis. A hypothesis and a recommendation is that meticulous attention be paid to surgical technique.

Current indications for pegging in the anophthalmic socket: are there any?

PURPOSE OF REVIEW

To highlight the development, problems, and current status of coupling porous orbital implants to the overlying prosthetic eye.

RECENT FINDINGS

Although increasing the risk of complications, pegging significantly contributes to prosthesis motility and satisfies the cosmetic expectations of some patients. Patients should be counseled regarding the increased risks in approximately one-third of individuals and that complications can occur even 10 years following implantation.

SUMMARY

Although implant peg placement has declined dramatically over the past decade, a precise and meticulous technique under intravenous anesthesia in the appropriately selected patient can be a successful outpatient procedure. Fortunately, most problems are of a minor nature, and over 85% of patients are able to retain their pegs following proper management and timely intervention. Additional visits to the ophthalmic plastic surgeon or ocularist are required that may not be necessary if a peg had not been placed.

Secondary orbital ball implants after enucleation and evisceration: surgical management, morbidity, and long-term outcome

PURPOSE

To investigate effectiveness of a simplified surgical technique for secondary ball implantation in anophthalmic sockets and to compare long-term results of secondary ball implantation in patients previously enucleated or eviscerated.

METHODS

The study is a case series analysis of the clinical charts of 110 consecutive patients who underwent secondary ball implantation after enucleation or evisceration, from January 1998 to December 2011, under the care of 1 surgeon. Patients undergoing primary evisceration and implant exchange were excluded. Primary surgery was due to trauma in 48.8% patients, endophthalmitis and phthisis bulbi in 25.6%, tumors in 22.1%, and orbital vascular malformations in 3.5%. This study adheres to the principles outlined in the Declaration of Helsinki.

RESULTS

Of 110 identified cases, 24 were excluded for insufficient follow-up (less than 2 years); mean follow-up was 6.4 years. Group A patients (previously enucleated) received a polyglactin mesh-wrapped implant. Group B patients (previously eviscerated) kept their own sclera as a secondary anterior capping on the polyglactin mesh-wrapped implant. There were 2 implant exposures (4.9%; 2 of 41) in group A. Hard palate graft was used to repair the exposed implant successfully. No exposure was noted in group B. No statistically significant between-group difference in exposure rate was found.

CONCLUSIONS

Stable secondary ball implantation can be achieved long term, and a reliable surgical technique is the most important factor in predicting implant stability. In patients who had secondary implants following evisceration, sclera and polyglactin mesh may act as duplicate barriers between anterior surface of implants and overlying tissues.

Fabrication techniques for ocular prostheses--an overview

The goals of treatment with ocular prostheses are to restore facial aesthetics and self-esteem to anophthalmic patients. Fabricated in acrylic resin, artificial eyes should be aesthetically pleasing, scratch-resistant, and adequately polished. Use of a prosthesis without such characteristics can lead to psychological damage, as well as infection and inflammation due to the accumulation of microorganisms and other substances on an irregularly shaped prosthesis. The present literature review describes the different techniques for fabricating ocular prostheses. Reproduction of the iris color and color stability are important factors that promote adequate aesthetics. The fabrication of an individual ocular prosthesis in acrylic resin provides satisfactory aesthetic results because the impression process establishes the defect contour. Additionally, the iris and sclera can be individually characterized. As the techniques, materials, and manufacturing methods for ocular prostheses continue to evolve, the aesthetics and functionality of prostheses will also improve.

Rate of vascularization and exposure of silicone-capped porous polyethylene spherical implants: an animal model

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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

Purpose

This study reports on the long-term surgical outcomes after the insertion of porous Medpor orbital implants into anophthalmic sockets.

Methods

A retrospective chart review of 314 eyes from 314 patients who underwent evisceration, enucleation and secondary procedures using Medpor orbital implants was completed focusing on implant-associated complications and their corrective methods as surgical outcomes.

Results

The mean follow-up was 50 months (range 6–107 months). The most common complication was blepharoptosis (n=33, 10.5%). Other postoperative complications were exposure (n=14, 4.5%) and implant infection (n=3, 1%). The complications were successfully managed by surgical repair and/or conservative care.

Conclusion

Using Medpor resulted in similar surgical outcomes, in terms of the types and frequencies of complications, as other kinds of porous orbital implants.

Late exposure of the bioceramic orbital implant

PURPOSE

To investigate the long-term outcome of the Bioceramic orbital implant.

DESIGN

A retrospective, comparative, nonrandomized study.

METHODS

Data were collected from the patients receiving Bioceramic orbital implants at National Taiwan University Hospital between June 1, 2001 and November 1, 2005. The implant was wrapped with Vicryl mesh, adding anteriorly with a scleral patch graft following enucleation with primary or secondary implantation. The unwrapped implant was inserted into an eviscerated globe with posterior sclerotomy and cornea preserved. Primary or secondary placement of sleeve was performed in some patients.

RESULTS

A total of 112 cases were reviewed. Four patients were excluded attributable to insufficient follow-up. The other 108 patients had a mean follow-up period of 35.8 +/- 10.6 months (range, 24 to 70 months). Fifty patients (46.3%) received the pegging procedure. Eight of 108 (7.4%) cases of late exposure were identified on average 20.7 months after implantation. We identified no cases of implant exposure in 30 cases of enucleation and eight cases of secondary implant when the implant was wrapped in Vicryl mesh and an anterior scleral cap was used. All exposures developed in eviscerated patients (70 cases): two without pegging, three with primary placement, and three with secondary placement of the sleeve. The exposure rate was higher in patients with eviscerated globes, pegged implants, and prior ocular operations (P < .005).

CONCLUSIONS

Late exposures of Bioceramic implants were found after long-term follow-up, associated with evisceration, pegging, and prior ocular surgeries. The modified wrapping technique can prevent exposure following secondary implantation and enucleation.

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

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Comparison of orbital volumes in enucleated patients with unilateral retinoblastoma: hydroxyapatite implants versus silicone implants

PURPOSE

To compare the difference in volume between enucleated and contralateral, uninvolved orbits in patients with unilateral retinoblastoma treated with primary enucleation who received either hydroxyapatite or solid silicone implants.

METHODS

In this retrospective, comparative interventional case series, data were reviewed for all patients (N = 33) with retinoblastoma at St. Jude Children's Research Hospital who underwent unilateral enucleation and received either hydroxyapatite or solid silicone implant from 1969 to 1999. Patients who received external beam radiation or systemic chemotherapy were excluded. CT and/or MRI were used to compare the difference in orbital volumes between the enucleated orbit and the contralateral orbit in 13 patients who underwent enucleation with hydroxyapatite implants vs. 20 patients who underwent enucleation with silicone implants. The main outcome measure was the difference in volume between enucleated and contralateral, uninvolved orbits correlated to implant material, which we determined using the Wilcoxon rank sum test.

RESULTS

The median difference in orbital volumes between enucleated and contralateral, uninvolved orbits was 0.9 cm (range, -3.78 to 3.09 cm; quartiles, -0.37, 2.72 cm; mean +/- standard error [SE], 0.76 +/- 0.64 cm; 95% confidence interval [CI], -0.49 to 2.01 cm) for patients treated with hydroxyapatite implants vs. 0.63 cm (range, -4.43 to 3.91 cm; quartiles, 0, 2.13 cm; mean +/- SE, 0.8 +/- 0.41 cm; 95% CI, -0.004 to 1.6 cm) in patients treated with silicone sphere implants. The median differences did not differ between the 2 types of implant (p = .74). The median follow-up time was 137 months (range, 10-244 months; quartiles, 37, 179 months; mean +/- SE = 118.31 +/- 22.83 months; 95% CI, 73.56-163.06 months) and 144 months (range, 57-251 months; quartiles, 98, 154 months; mean +/- SE, 136.1 +/- 10.78 months; 95% CI, 114.97-157.23 months), respectively.

CONCLUSIONS

In unilateral retinoblastoma patients treated with primary enucleation, hydroxyapatite-integrated orbital implants provide no better symmetry of orbital volume than do more traditional silicone implants.

Complications of orbital implants: a review of 542 patients who have undergone orbital implantation and 275 subsequent PEG placements

PURPOSE

To inform patients and physicians of the complications associated with three commonly used orbital implants, as well as associated anophthalmic socket issues.

METHODS

A retrospective chart review of 542 patients who underwent eviscerations, enucleations and secondary procedures by one surgeon (Dr. James Oestreicher) was completed, paying special attention to complications in the follow-up period prior to pegging, as well as those that occurred post-pegging.

RESULTS

Approximately 60% of patients experienced complications prior to implant drilling, with discharge being the most prevalent (15.9%). Secondary procedures were associated with significantly greater complication rates prior to implant drilling. Silicone implants had significantly less pre-pegging pyogenic granuloma (P = 0.011) and hypo-ophthalmos (P = 0.042) than the other implant types. Seven implants had to be removed due to exposure. Implant drilling and peg placement were performed in 275 patients. Implant drilling complications were experienced by 67.4% of pegged patients, with a change in discharge from prior to pegging (27.2%) being the most prevalent. Plastic peg systems had a significantly higher incidence of complications than titanium systems.

CONCLUSIONS

The majority of orbital implantations involve complications, these being largely minor ones which resolve spontaneously or are easily treated. Secondary implant procedures involve a higher likelihood of complications. Silicone implants have the smallest amount of complications. Should patients decide to undergo pegging, evidence sides strongly for the use of a titanium peg and sleeve system over the other peg types. Implant removal is a rare event; occurring in 1.3% (n = 7) of the study population.

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.

Complications of primary placement of motility post in porous polyethylene implants during enucleation

PURPOSE

To evaluate the complications associated with the primary placement of a motility coupling post (MCP) in spherical porous polyethylene (PP) implants at the time of enucleation.

DESIGN

Retrospective, interventional case series.

METHODS

The records of all patients who had undergone primary enucleation and spherical PP implant with MCP insertion, and who were followed for at least six months were reviewed. The MCP was screwed to a wrapped implant to protrude 3 mm to 4 mm anteriorly. After placing the implant into the orbit, the extraocular muscles were sutured to the implant, and the Tenon capsule and conjunctiva were closed onto the MCP. When the MCP was not exposed spontaneously within two months after surgery, it was externalized with a conjunctival cut-down procedure.

RESULTS

The study included 52 patients (29 male, 23 female; age range, three to 76 years). The MCP became exposed spontaneously in 10 patients (19%). In the early postoperative period, we recorded nine complications in seven patients (13%), which might be related to primary MCP placement. These included prominent MCP decentration associated with implant motility restriction (6%), preseptal cellulitis (4%), and conjunctival prolapsus (8%). An ocular prosthesis was fit successfully onto the MCP in 51 patients. During the late period, 22 complications occurred in 15 patients (29%), including excessive discharge (15%), MCP decentration (4%), implant exposure (6%), implant infection (2%), pyogenic granuloma (8%), conjunctival overgrowth over the MCP (2%), conjunctival discoloration (4%), and lax eyelid syndrome (2%). Mean follow-up time was 34 months (range, six to 68 months).

CONCLUSIONS

Although MCP placement in the spherical PP implant during enucleation is a useful technique, it may be associated with complications such as MCP decentration, excessive discharge, exposure, and infection of the implant.

Porous Implant Exposure: Incidence, Management, and Morbidity

PURPOSE

To identify what factors may predispose patients to exposure of porous anophthalmic implants and to determine the outcome of exposed porous implants.

METHODS

Examination of pooled data obtained through a PubMed literature search of English-language publications from 1989 through 2004 using the key words enucleation, evisceration, and socket reconstruction.

RESULTS

Porous implants were inserted in 80% (3012 of 3777) of the cases identified from 49 publications. The difference in exposure rate between coralline hydroxyapatite (4.9%) and porous polyethylene (8.1%) implants is primarily related to a higher reported complication rate of uncovered porous polyethylene implants, particularly in retinoblastoma patients. Other techniques associated with increased exposures include wrapping implants with bovine pericardium or polyglactin mesh. Evisceration and secondary procedures did not have statistically different complication rates compared with enucleation. There are more late exposures of porous polyethylene than coralline hydroxyapatite implants. Spontaneous healing of exposures occurred in 13% (19 of 145) of cases. Covering exposures with patch grafts underneath vascularized conjunctival flaps was the most successful method of surgical repair. Implant removal was necessary after 29% (42 of 145) of exposures.

CONCLUSIONS

Although the published literature between 1989 and 2004 reports higher complication rates for uncovered porous implants and implants wrapped with bovine pericardium or polyglactin mesh, pooling data from different studies may mask very good or poor results obtained by individual surgeons. Spontaneous healing of exposed porous implants is relatively uncommon. However, many exposed porous implants can be salvaged with secondary repair.

Prevention of exposure of porous orbital implants following enucleation

PURPOSE

To investigate effectiveness of adding a scleral patch graft on a Vicryl mesh-wrapped porous orbital implant to prevent exposure following enucleation.

DESIGN

A retrospective, comparative, nonrandomized study.

METHODS

From October 1996 to February 2006, 74 consecutive patients (74 sockets) who received porous orbital implants primarily or secondarily after enucleation at National Taiwan University Hospital (72 cases) and at Far Eastern Memorial Hospital (2 cases) were collected. Patient demographics, ocular diagnosis, the surgical technique, prior ophthalmic surgery, type, covering, and size of the implant, follow-up periods, and complications associated with pegs and implants were recorded. Group 1 patients received a Vicryl mesh-wrapped implant without a scleral patch graft. Group 2 patients received anterior capping with a scleral patch on the Vicryl mesh-wrapped implant.

RESULTS

Of 74 identified cases, 12 were excluded for insufficient follow-up. The 62 remaining cases had more than a two-year follow-up. There were two implant exposures (12%, two of 17) in group 1. Retroauricular myoperiosteal graft and scleral patch were used to repair exposed implants successfully. No exposure was noted in group 2 (n = 45). A significant between-group difference in exposure rate was found (P = .02). Early conjunctival dehiscence followed by spontaneous healing occurred in three group 2 patients.

CONCLUSIONS

Scleral patch graft and Vicryl mesh can act as duplicate barriers between anterior surface of implants and overlying soft tissue. The modified wrapping technique prevents porous implants from exposure effectively.