Porous orbital implants, wraps, and PEG placement in the pediatric population after enucleation

The Scleral Cap Technique for Porous and Nonporous Orbital Implants

PURPOSE

To describe the results and potential benefit of a banked homologous donor scleral cap over the anterior surface of polyglactin 910 mesh-wrapped porous and nonporous orbital implants during enucleation and secondary orbital implant surgery.

METHODS

This is a single center, retrospective, clinical case series of 83 patients who received a polyglactin 910 mesh (Vicryl knitted mesh, undyed, Ethicon, Sommerville, New Jersey, USA) wrapped bioceramic or polymethylmethacrylate orbital implant (sphere or mounded) following enucleation and secondary orbital implant surgery by one surgeon over a 10-year period. A homologous donor scleral cap (approximately 1.5 × 1.5 cm diameter) was also placed over the anterior mesh-wrapped implant surface as an additional barrier. A minimum of 1-year follow up was required to be included in the study. The author analyzed patient demographics, type of surgery, implant type, implant size, follow-up duration, and presence or absence of implant exposure. The data from patients with greater than 1-year follow up are detailed in this report.

RESULTS

The author identified 100 patients in his case files that had a scleral cap put in place over their implant. Seventeen patients were either lost to follow up or did not have at least a 1-year follow up, leaving 83 patients (44 enucleations, 39 secondary implants) that were followed for 12 to 120 months (average 60.5 months). There were no cases of implant exposure identified in either group of patients during this time period.

CONCLUSIONS

Implant exposure can occur anytime post implant placement with a porous or nonporous orbital implant. This review suggests that a homologous donor scleral cap (approximately 1.5 × 1.5 cm diameter) over the polyglactin 910 mesh-wrapped implant surface may help prevent implant exposure. Patients with porous and nonporous orbital implants should be followed on a long-term basis as exposure can occur at anytime postsurgery, even several years later.

Porous orbital implant after enucleation in retinoblastoma patients: indications and complications

This study aims to identify risk factors associated with complications in retinoblastoma patients following primary and secondary enucleations with porous implant placement. A retrospective case-control study was performed between 2010 and 2015. Data pertaining to subjects' demographics, medical history, clinical, and pathological findings, implant characteristics and complications were collected. The analysis included 103 eyes of 101 patients age 27.8 ± 21.9 months undergoing enucleation for retinoblastoma. Postoperatively, 19/103 (18%) eyes developed exposure, extrusion, or hematoma requiring subsequent surgery. Exposure was the most common postoperative complication (12/19, 63%). Age at enucleation 24 months or younger, Hispanic ethnicity, female gender, and intravenous chemotherapy prior to enucleation were associated with increased odds of implant complications. In contrast, patients who were given intravitreal melphalan (IM), subtenons carboplatin (SC), or external beam radiation therapy (EBRT) did not demonstrate an increased risk of complications. In this cohort of retinoblastoma patients undergoing primary or secondary enucleation with porous implants, implant exposure was the most common postoperative complication. Our findings suggest that female gender, Hispanic ethnicity, age at enucleation 24 months or younger, and intravenous chemotherapy prior to enucleation may increase the risk of complications.

Orbital implants in retinoblastoma patients: 23 years of experience and a review of the literature

PURPOSE

To evaluate complications of different types of orbital implants following enucleation for retinoblastoma.

METHODS

We performed a retrospective chart study of all patients that underwent enucleation as treatment of retinoblastoma between April 1991 and June 2013. Events of implant exposure, extrusion (defined as a complete loss of the implant, or a major exposure that could not be closed) and socket abnormalities were analysed for association with implant type and influence of additional external beam radiation therapy (EBRT) and/or chemotherapy.

RESULTS

A total of 224 enucleations in 216 patients (eight bilateral) were identified. Mean age at surgery was 1.9 (median 1.5) years. Of the 219 included enucleated eyes, 20 were not replaced by a primary implant and 18 were replaced by an Allen implant. Scleral wrapped hydroxyapatite (HA) and acrylic implants (polymethylmethacrylate) were inserted in, respectively, 79 and 102 cases. In the total population, 29 treatment or implant-specific events (13.2%) were registered. Main complications were implant exposure n = 10 (4.6%) and extrusion n = 6 (2.7%). The acrylic/sclera group had less exposures or extrusions (5 of 102, 4.9%) compared to the HA/sclera group (10 of 79, 12.7%), although this difference did not quite reach statistical significance (p = 0.06). Additional treatment (chemotherapy and/or EBRT for the fellow eye) was administered in 78 cases (35.8%). The overall complication rate in the entire study population was significantly higher (16.7% versus 5.7%) in the group exposed to additional therapy (OR 3.3; 95% CI 1.30-8.36 p = 0.008). This negative effect of additional therapy was also significant in the combined acrylic/HA group (OR 2.9; 95% CI 0.97-8.46 p = 0.048).

CONCLUSION

Our results suggest a favourable outcome for acrylic implants compared to the HA implant. Additional treatment with chemotherapy and/or EBRT is associated with an increased risk of complications.

Use of the anterolateral thigh flap for reconstruction of the pediatric anophthalmic orbit

Children with acquired anophthalmia pose unique reconstructive challenges. With implant-based reconstruction, the current standard of care, there is a tendency toward intraorbital and adnexal tissue contraction and an increasing volume discrepancy with orbital growth, resulting in enophthalmos and eyelid retraction, and also difficulty in retaining an ocular prosthesis. We describe a novel technique for secondary reconstruction of the pediatric anophthalmic orbit using a small free anterolateral thigh (ALT) flap. The technique involves release of retracted eyelids and restoration of orbital volume with an ALT flap based on the superficial temporal vessels. The purpose of this study is to detail the results of treatment of a series of four consecutive patients with unilateral acquired anophthalmia managed with ALT flaps. Improved symmetry, successful retention of an ocular prosthesis, and patient satisfaction were achieved in all cases.

Fibrovascular ingrowth into porous polyethylene orbital implants (Medpor) after modified evisceration

PURPOSE

To evaluate, using MRI, the extent and pattern of fibrovascular ingrowth into Medpor implants after modified evisceration.

METHODS

Contrast T1-weighted images were performed in 21 patients within 1.5- to69-month intervals after modified evisceration with primary Medpor implantation. In 6 patients, the images were obtained separately following 1- and 5-minute delays after contrast administration.

RESULTS

No grade I enhancement occurred in these series. Grade II was observed in 2 patients (9.09%), grade III in 8 patients (36.36%), grade IV in 9 patients (40.91%), and grade V in 3 patients (13.64%). Significant correlation existed between the grade of enhancement and the postevisceration interval (r = 0.483, p = 0.023 < 0.05). The images demonstrated an enhancement pattern that started at the unwrapped posterior pole and anterior location of rectus muscles with progressive centripetal vascularization toward the center of the implant. At the early stage of recovery, the fibrous connective tissue was thick in front of Medpor spheres. In the 5-minute delay images of 6 patients, 2 patients failed to exhibit further enhancement; 2 patients exhibited enlarged and homogeneous enhancement; and 2 patients revealed more intense enhancement patterns. The medical ethics committee of Zhongshan Ophthalmic Center approved the study.

CONCLUSIONS

Fibrovascular ingrowth into Medpor implants was satisfactory after the modified evisceration and correlated with the duration of the implants. The double layers of sclera effectively prevented the implant extrusion and exposure. The authors recommend waiting at least 5 minutes before obtaining MR images after contrast administration.

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.

Comparative study of modified and conventional secondary hydroxyapatite orbital implantations

AIM

To compare the clinical effects of the modified and conventional secondary hydroxyapatite orbital implantations.

METHODS

A total of 40 patients who had received eye enucleation were equally randomized into the modified and conventional groups. Twenty patients were treated by conventional method. The four rectus muscles were separated, and then an orbital implant wrapped with xenogenous sclera was implanted. Twenty patients were treated by modified method. An implant unwrapped with xenogenous sclera was directly implanted into the muscle pyramid. The operating time, costs, clinical effects, and complications of the two groups were compared.

RESULTS

The average operating time of the modified group was 20.5±5.6min, whereas that of the conventional group was 56.8±14.6min (P<0.01). The average cost of the modified group was 7 800±340RMB (1 274±55.6USD), whereas that of the conventional group was 9 800±660RMB (1 601±107.8USD) (P<0.01). The two groups did not show significant difference in orbital implant mobility or postoperative complications.

CONCLUSION

The modified secondary hydroxyapatite orbital implantation has advantages in operating time, surgery cost, and complication reducing. It is worthy for wide clinical application and further study.

Pediatric anophthalmic sockets and orbital implants: outcomes with polymer-coated implants

PURPOSE

To compare wrapped and polymer-coated hydroxyapatite implants in children undergoing primary enucleation with no adjuvant therapies.

DESIGN

Retrospective, interventional cohort study.

PARTICIPANTS

All children undergoing primary enucleation without adjuvant therapies between 1999 and 2009 at a tertiary pediatric cancer hospital.

METHODS

Review and analysis of patient records.

MAIN OUTCOME MEASURES

Implant exposure, extrusion and migration, socket contracture, and formation of pyogenic granuloma.

RESULTS

Sixty consecutive patients undergoing primary enucleation with no adjuvant chemotherapy or radiation with follow-up of at least 12 months were included. Retinoblastoma was the diagnosis in 59 eyes (98.3%). Median follow-up was 3.6 years (range, 1.0-9.3 years). Two implant sizes were used: 20 mm in 47 patients (78.3%) and 18 mm in 13 patients (21.7%). Overall, 52 patients (86.7%) had an event-free recovery. Polymer-coated hydroxyapatite implants (43/60, 71.7%), when compared with wrapped ones (17/60, 28.3%), had a trend toward greater event-free recovery (odds ratio [OR], 1.6; 95% confidence interval [CI], 0.3-7.7) and lower exposure rate (OR, 2.1; 95% CI, 0.4-10.5).

CONCLUSIONS

The use of polymer-coated hydroxyapatite implants is associated with favorable outcomes in the pediatric population. Despite observed complications, long-term implant retention is possible in most children.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

The effect of cancer therapies on pediatric anophthalmic sockets

PURPOSE

To determine the impact of chemotherapy or external beam radiotherapy (EBRT) on pediatric anophthalmic sockets.

DESIGN

A retrospective, nonrandomized, interventional cohort study.

PARTICIPANTS

A total of 135 sockets of 133 children undergoing enucleation from late 1999 to early 2009 at the St. Jude Children's Research Hospital were included.

METHODS

A retrospective chart review of outcomes after enucleation in patients treated with systemic chemotherapy or orbital EBRT either before or after removal of the eye compared with patients who received no other treatment.

MAIN OUTCOME MEASURES

Incidence of implant exposure, migration, extrusion, socket contracture, and pyogenic granuloma formation.

RESULTS

Retinoblastoma was the primary diagnosis in 128 eyes (95%). Median follow-up was 3.6 years (range, 0.1-9.3 years). Event-free course was observed in 94 sockets (69.6%). Complications included implant exposure (n = 28, 20.7%), socket contracture (n = 16, 11.9%), pyogenic granuloma (n = 9, 6.7%), implant extrusion (n = 3, 2.2%), and migration (n = 2, 1.5%). Exposure resolved in 21 sockets (77.8%) and improved in 2 sockets (11.1%); 1 patient with exposure died. Use of prior, adjuvant, or subsequent chemotherapy increased the long-term risk of exposure (odds ratio [OR] = 3.7; 95% confidence interval [CI], 1.4-9.4), and contracture (OR could not be calculated, P<0.0001). External beam radiotherapy greatly increased the risk of contracture (OR 24.0; 95% CI, 6.9-82.8) and exposure (OR 2.89; 95% CI, 1.1-7.9).

CONCLUSIONS

In this unique pediatric population with cancer, chemotherapy and EBRT had an additive effect, significantly increasing the incidence of exposure and socket contracture.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Frequent prosthesis refitting to prevent implant exposure in patients with retinoblastoma

PURPOSE

To examine the effects of prosthesis refitting on porous orbital implant exposure in 100 patients who underwent enucleation for retinoblastoma.

METHODS

Parameters analyzed included patient's age at enucleation, gender, implant type, frequency of prosthesis adjustment, and use of chemotherapy or radiation. The main outcome measures consisted of the condition of the fornices, condition of the implant (including conjunctival thinning), and condition and functioning ability of the prosthesis.

RESULTS

Increased frequency of visits with the ocularist and number of prosthesis adjustments and refits significantly improved the condition of the implant, fornices, and prosthesis. The patient's age at enucleation, gender, and use of chemotherapy or radiation did not have a significant effect on any of the outcome variables. The condition of the implant was significantly better for porous polyethylene than hydroxyapatite implants (P = .024). No implant exposures were observed.

CONCLUSION

Frequent adjustments and refits by the ocularist are significantly associated with a reduced rate of conjunctival thinning and complete avoidance of implant exposure in patients undergoing enucleation for retinoblastoma. These findings are particularly significant for this population, which historically has demonstrated a high rate of implant exposure.

Scleral wrap increases the long-term complication risk of bone-derived hydroxyapatite orbital implants

BACKGROUND

This study was prompted by previous findings that suggested that scleral wrapping increased the rate of complications following insertion of bone-derived hydroxyapatite orbital implants and compared the long-term results of implants inserted with and without scleral wraps.

METHODS

This retrospective case series reviewed the long-term outcomes of 159 patients who had undergone enucleation with insertion of a bone-derived hydroxyapatite orbital implant at Dunedin Hospital between 1977 and 2006. Implants were inserted with and without scleral wraps in 85 and 74 cases, respectively. Follow up was 0.5-27.5 years (mean 8.2 years) for the whole series and 9.7 years for the sclera group and 6.7 years for the group without sclera. Patient details were obtained from theatre records, case note review, patient interview and examination, interview of patient relatives and family general practitioner records. The main outcome measures were the rates of minor or major complications and their treatments and outcomes.

RESULTS

Twenty-seven cases (17%) suffered minor complications of limited implant exposure that either healed spontaneously, with implant drilling or wound resuturing and 11 cases (7%) suffered major complications requiring explantation. Of 38 patients with postoperative complications, 31 (82%) had scleral wraps compared with 7 (18%) without sclera (P < 0.001; OR 5.14, 95% CI 2.00-14.78).

CONCLUSION

Bone-derived hydroxyapatite orbital implants inserted without scleral wrap were associated with better clinical outcomes and a lower rate of long-term complications. It is therefore recommended that these implants be inserted without a scleral wrap.

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.