Dermis-fat graft for treatment of exposed porous polyethylene implants in pediatric postenucleation retinoblastoma patients

PURPOSE

To demonstrate the use of the autogenous dermis-fat graft for the treatment of porous polyethylene implant exposure and volume augmentation in postenucleation retinoblastoma children.

DESIGN

Retrospective, interventional case series.

METHODS

Ten children who received a dermis-fat graft at Seoul National University Hospital between July 1, 2005 and January 31, 2010 were included in this study. The patients had undergone unilateral enucleation for retinoblastoma, and received a subconjunctival dermis-fat graft to repair implant exposure and simultaneously correct enophthalmos. The clinical characteristics of the patients, rate of graft survival, and complications were analyzed. The cosmetic outcome was assessed using a grading system.

RESULTS

All patients had enucleation using porous polyethylene implant as a primary orbital implant. The average time to exposure was 89.1 ± 22.4 months and the median size of defect was 2 × 3 mm. With a mean follow-up of 28 months, 9 of 10 patients showed well-survived graft without re-exposure. One patient who experienced a graft failure managed with implant rotation and a scleral graft. Seven patients showed significant improvement of enophthalmos.

CONCLUSIONS

Implantation of an autogenous dermis-fat graft is a procedure that can be effectively used to treat porous polyethylene implant exposure and simultaneously correct enophthalmos. Use of this procedure can be particularly advantageous for pediatric postenucleation patients.

Ultrastructural investigation of intact orbital implant surfaces using atomic force microscopy

This study examined the surface nanostructures of three orbital implants: nonporous poly(methyl methacrylate) (PMMA), porous aluminum oxide and porous polyethylene. The morphological characteristics of the orbital implants surfaces were observed by atomic force microscopy (AFM). The AFM topography, phase shift and deflection images of the intact implant samples were obtained. The surface of the nonporous PMMA implant showed severe scratches and debris. The surface of the aluminum oxide implant showed a porous structure with varying densities and sizes. The PMMA implant showed nodule nanostructures, 215.56 ± 52.34 nm in size, and the aluminum oxide implant showed crystal structures, 730.22 ± 341.02 nm in size. The nonporous PMMA implant showed the lowest roughness compared with other implant biomaterials, followed by the porous aluminum oxide implant. The porous polyethylene implant showed the highest roughness and severe surface irregularities. Overall, the surface roughness of orbital implants might be associated with the rate of complications and cell adhesion.

The effect of autologous serum eye drops on the conjunctivalization over exposed porous polyethylene orbital implant (Medpor(®)) in the rabbit model

PURPOSE

To assess the efficacy of autologous serum eye drops (AS) in enhancing conjunctivalization over a scleral patch graft on exposed porous polyethylene orbital implant (Medpor(®)).

METHODS

Eighteen rabbits were underwent evisceration, implantation of Medpor(®) and homologous scleral patch graft. The conjunctival edge was sutured leaving 5 mm-diameter circular defect. In group A, 20% AS were applied 8 times a day and only balanced salt solution was applied in group B. Digital anterior segment photography was obtained 1, 3, 7, 10, 14, and 21 days after surgery and analyzed with Image Pro Plus(®) software.

RESULTS

In the early postoperative period, the average conjunctival growth rate (mm(2)/day) was faster in group A, but failed to show statistical significance (3.79 vs. 3.03, p = 0.26 in 1~3days, 2.39 vs. 1.80, p = 0.59 in 4- days, 0.03 vs. -0.02, p = 0.94 in 7-10 days, Mann-Whitney test). The complete healing rate was higher (67% vs. 56%, p = 0.5, Fisher's exact test) and the mean elapsed time for complete healing (days) was shorter in group A (17.3 vs. 18.2, p  = 0.83, Mann-Whitney test), but did not show a statistically significant difference.

CONCLUSION

In a rabbit model, 20% AS did not appear to facilitate the healing of small conjunctival defects of exposed porous orbital implant.

Enduragen patch grafts for exposed orbital implants

PURPOSE

To present a new technique using the recently introduced Enduragen(®) material (Tissue Science Laboratories) as a patch graft for exposed ocular implants.

METHODS

A retrospective, interventional, non-comparative case series of 3 patients who had Enduragen patch grafts for the closure of Tenon's capsule and conjunctiva over exposed ocular implants. Medical records were reviewed and the following parameters were collected: age, gender, indication for surgery, type of surgery, laterality, type of orbital implant, complications after repair and length of follow-up.

RESULTS

Three patients were identified, 2 males and 1 female. One patient had a secondary quad-motility implant with supertemporal exposure. The second patient had a secondary implant with a fistula at the lateral aspect of the socket. The third patient had a centrally exposed primary hydroxyapatite implant. All patients received Enduragen patch grafts to cover the implant. Follow up ranged from 40 to 43 months (mean, 41.3 months; SD, ± 1.5). None of the 3 patients had any signs of implant re-exposure at the time of the last post-operative visit. There were no intra-operative or early complications observed.

CONCLUSIONS

This consecutive case series suggests that Enduragen could be used as a safe and effective patch graft for exposed ocular implants. However, a larger prospective study with longer follow-up would be useful in further defining the indications and limitations of the Enduragen patch graft for the treatment of exposed orbital implants.

MR imaging of progressive enhancement of a bioceramic orbital prosthesis: an indicator of fibrovascular invasion

The physical properties of bioceramics have made them ideal for a variety of prosthetic devices. Their porous structure allows fibrovascular tissue to invade the implant and secure it and provides a surface for muscular attachment. This process has been well-documented in animal studies; however, this case report describes the periodic imaging changes seen in a 67-year-old man following placement of a bioceramic orbital prosthesis.

[Rationale for implant insertion after enucleation of eyes with uveal melanoma]

Results of retrospective analysis of medical charts of 328 patients after enucleation due to uveal melanoma (UM) are represented. Our study showed that recurrent tumor occurs in 2.44% cases. The main reasons of recurrence are scleral invasion or tumor damage during surgery. After enucleation due to juxtapapillary UM recurrence is rare and occurs after long-term follow-up. Thus after enucleation due to UM implant insertion is possible in case of scleral integrity and absence of macroscopically apparent tumor extension beyond sclera.

[Study of the three-dimensional structure and biointegrative characteristics of porous orbital implant materials]

Plastic repair operations in ophthalmic surgery frequently require the use of various biological and artificial implants. The biointegrative properties of implants are provided by the physicochemical characteristics of the material that is used to make them, by the three-dimensional structure of an implant and its immunological characteristics. The authors comparatively studied the three-dimensional structure of a Carbotexim-M carbonic felt, porous polyethylene, polytetrafluoroethylene, demineralized bone alloimplant, and marine coral hydroxyapatite, which are employed in orbital surgery and also examined the adhesion of fibroblasts to their surface. Comparative study using scanning electron microscopy could reveal the specific features of the relief and parameters of the threshold space of the study implant materials. A method was developed to estimate cell adhesion to the implant materials, by taking into account three-dimensional structure of their surface.

[Role of primary and stepwise prosthetic replacement in the rehabilitation of subjects with anophthalmos]

The study covered 1980 patients with anophthalmos and a cosmetically poor blind eye, who were followed up in the ocular prosthesis room, Helmgoltz Institute of Eye Diseases. The optimal periods of primary and stepwise prosthetic replacement are defined and standard ocular prostheses of the most appropriate shape and size are recommended depending on the specific features of the conjunctival cavity and stump in this period. Recommendations are given on the application of ocular prostheses in congenital pathology and subatrophy.

Rigid nylon foil-anchored polytetrafluoroetyhlene (Gore-Tex) sheet stenting for conjunctival fornix reconstruction

PURPOSE

To describe an operative technique that deepens foreshortened conjunctival fornices by providing a scaffold for epithelialization that opposes contractile forces during wound healing.

DESIGN

Retrospective interventional case series.

PARTICIPANTS

Seventeen patients with anophthalmic sockets containing foreshortened conjunctival fornices.

METHODS

Conjunctival fornices was reconstructed with stents of expanded polytetrafluoroethylene (e-PTFE) sheet draped over rigid, 0.8-mm thick-nylon strips that were anchored to the orbital rim. Preoperative and postoperative symptoms, prosthesis retention, fornix depth, and lagophthalmos were assessed.

MAIN OUTCOME MEASURES

Prosthesis retention, fornix depth, and lagophthalmos.

RESULTS

All 17 patients had preoperative inability to retain their prosthesis. After postoperative follow-up of 47+/-43 months, retention was improved in all patients and was entirely satisfactory in 15 (88%) patients. After reconstruction, the repaired fornix was deep in 7 (41%) patients, adequate to retain a prosthesis in 9 (53%), and shallow in 1 (6%). Lagophthalmos improved in 15 (88%) patients and remained unchanged in 2 (12%). The superior fornix was reconstructed concurrently with the inferior fornix in 6 patients. In these patients, the superior fornix improved to deep (3 patients; 50%) or adequate (2; 33%). In 1 (17%) patient, it remained shallow.

CONCLUSIONS

Rigid, nylon foil-anchored e-PTFE stenting opposes postoperative contracture, improving prosthesis retention, and lagophthalmos. It does not require an additional surgical site for graft harvesting.

The use of autologous dermis grafts for the reconstruction of the anophthalmic socket

PURPOSE

The main objectives of enucleation, evisceration or secondary orbital implants are to replace orbital volume and obtain good motility and adaptation of the implant and the external prosthesis. We describe our experience using autologous dermis graft sutured to Tenon and conjunctiva following evisceration, enucleation and any reconstruction requiring either a primary or secondary orbital implant, even those with large tissue loss.

MATERIALS AND METHODS

A retrospective case series of patients who received an autologous dermis graft to assist in closure of a Tenon's capsule and conjunctiva at the time of placement of secondary orbital implants or evisceration or enucleation with fornices retraction or tension in tissues. We also describe how and from where to take the dermis graft.

RESULTS

72 patients were included and all received orbital porous polyethylene implants: 28 patients had secondary orbital implants, 36 patients had evisceration and 8 patients had enucleation. Implant size was 20 mm in most cases, but went to 22 mm. Follow-up ranged from 3 to 36 months. No intraoperative complications were observed in donor or receptor area. 8 cases had incipient ischemia of the dermis graft, but were treated and resolved with autologous serum.

CONCLUSIONS

Implant exposure is due to bad surgical technique, an inadequate implant size or excessive tension on the suture. Dermis autologous graft allows moving the orbital implant anteriorly because it replaces surface to suture Tenon and conjunctiva without tension, so a good adaptation of a thinner external prosthesis is possible, resulting in better motility.

Fabrication of a surgical template for orbital implant placement: a case report

Implant placement in orbital sites is challenging because of limited bone volume and poor bone quality. Preoperative optimal implant planning and intraoperative guides are important to ensure success. This article describes the use of computer simulation for implant insertion and fabrication of a surgical template as a drilling guide for orbital implant placement. A 29-year-old woman with a right orbital defect underwent computerized tomographic scanning, and the data were processed with interactive software to simulate orbital implant placement. A surgical template that served as a drilling guide was designed and fabricated to transfer orbital recipient site information from the three-dimensional computer model into the actual orbital implant sites. Three craniofacial implants were placed in the 7:00, 8:00, and 11:00 positions. No unexpected complications or injuries were encountered during the surgery. Magnetic abutments were attached to the implants 2 weeks later. The definitive facial prosthesis was fitted 6 months later, with excellent esthetic results. The surgical template contributed to the success of this treatment.

Dimensional accuracy of computer-aided design/computer-assisted manufactured orbital prostheses

PURPOSE

The aim of this research was to assess the dimensional accuracy of orbital prostheses based on reversed images generated by computer-aided design/computer-assisted manufacturing (CAD/CAM) using computed tomography (CT) scans.

MATERIALS AND METHODS

CT scans of the faces of 15 adults, men and women older than 25 years of age not bearing any congenital or acquired craniofacial defects, were processed using CAD software to produce 30 reversed three-dimensional models of the orbital region. These models were then processed using the CAM system by means of selective laser sintering to generate surface prototypes of the volunteers' orbital regions. Two moulage impressions of the faces of each volunteer were taken to manufacture 15 pairs of casts. Orbital defects were created on the right or left side of each cast. The surface prototypes were adapted to the casts and then flasked to fabricate silicone prostheses. The establishment of anthropometric landmarks on the orbital region and facial midline allowed for the data collection of 31 linear measurements, used to assess the dimensional accuracy of the orbital prostheses and their location on the face.

RESULTS

The comparative analyses of the linear measurements taken from the orbital prostheses and the opposite sides that originated the surface prototypes demonstrated that the orbital prostheses presented similar vertical, transversal, and oblique dimensions, as well as similar depth. There was no transverse or oblique displacement of the prostheses.

CONCLUSION

From a clinical perspective, the small differences observed after analyzing all 31 linear measurements did not indicate facial asymmetry. The dimensional accuracy of the orbital prostheses suggested that the CAD/CAM system assessed herein may be applicable for clinical purposes.

[Materials used in orbital surgery]

Implant materials for orbital surgery are mainly used during orbital traumatic deformity-eliminating operations, postenucleation stump plasty, evisceration, and anophthalmic syndrome correction. There are currently a lot of biological and artificial implant materials, but there is no universal material to correct all types of defects and this makes surgeons use a great quantity of reparative procedures and techniques and scientists continue to search for more suitable implant materials. This paper reviews the currently available materials used in orbital surgery in Russia and foreign countries.

Review of 345 eye amputations carried out in the period 1996-2003, at Rigshospitalet, Denmark

PURPOSE

The aim of this study was to identify the number of eye amputations, and the causative diagnoses, indications for surgery and surgical techniques applied, and to evaluate a possible change in surgical technique in a tertiary referral centre in Denmark.

METHODS

The hospital database was screened using surgery codes for patients who had undergone bulbar evisceration, enucleation or orbital exenteration in the period 1996-2003. Patient records were reviewed for gender, age, time since surgery, causative diagnosis (the disease process leading to the indication for amputation), indication for eye amputation, type of surgery and whether an implant was applied.

RESULTS

A total of 345 patients were identified as having undergone eye amputation during the 8-year period. Indications for eye amputation were: painful blind eye (127); neoplasm (119); infection (42); recent injury (25); disfiguring blind eye (25); prevention of sympathetic ophthalmia (5), and other reasons (2). Surgical procedures included 174 eviscerations, 154 enucleations and 17 orbital exenterations. The mean number of surgeries per year was 43.1. An orbital implant was applied in 168 patients.

CONCLUSIONS

The most frequent indications for eye amputation were painful blind eye (37%) and neoplasm (34%). During the study period, the annual number of eye amputations was stable, but an increase in bulbar eviscerations was noticed. Orbital implants were used in 33% of patients in 1996 and 67% in 2003.

Team approach in treatment of extensive maxillofacial defects - five case report serie

Long-lasting functional and esthetic rehabilitation and good health-related quality of life of patients with maxillofacial defects is based on effective interdisciplinary cooperation especially of surgeons, dentists and technicians. Extensive defects occur after the first phase of the oncologic surgery and immediately after injuries. Subsequent plastic surgery is the initial step of functional reconstruction and creates a base for future fabrication of post-operative dentures and implant-born epitheses. Five clinical reports demonstrate complex rehabilitation of typical maxillofacial defects solved within the multidisciplinary cooperation. Four patients with oncological diagnoses and complex surgical treatment, resp. radio- and chemotherapy are reported with interim and long-term prosthetic solutions. One patient suffered from a congenital malformation. Titanium implants were inserted in defect bone margins using two-phase method. Healing time was at minimum three months and after this period superstructures were applied. Artificial eyes were made of both glass and acrylic materials. Retention of presented postoperative prostheses was reliable; patients were satisfied with the functional and esthetical results of the reconstruction. Prognosis of the rehabilitation depends on the histological stability of adjacent tissues, quality of osseointegration and durability of materials used (silicones, acrylates). Satisfactory health-related quality of life of these patients is based on the multidisciplinary healthcare.

Therapy of percutaneous infection around craniofacial implants

This study sought to develop treatment strategies for managing percutaneous infection around craniofacial implants. The present general pathogen situation together with a bacterial resistance were determined in 57 infected peri-implant sites. Forty-four implants were randomly assigned for wound cleaning and split into three groups-two with local antibiotics of proven efficacy and one with 3% hydrogen peroxide (H2O2). The pathogen spectrum differed depending on the severity of the infection, with Staphylococcus aureus clearly correlated with the degree of inflammation (positive correlation: R = 0.72). It was observed that the use of additional local antibiotics was not superior to conventional wound cleaning with 3% H2O2. It is suggested that sulcus fluid flow rate measurements could serve as a simple and reliable objective parameter for recall examinations.

A histopathologic study of orbital implant vascularization

PURPOSE

To histopathologically assess the extent and pattern of vascularization of explanted porous polyethylene (PP) and hyrdoxyapatite (HA) orbital implants. To compare the vascularization in PP implants harvested after enucleation versus after evisceration.

METHODS

This is a comparative case series of six orbital implants explanted between 11 months and 5 years and 4 months post implantation. The implants were subjected to histopathological examination with various stains, after complete decalcification.

RESULTS

There were 2 post evisceration, 3 post enucleation and 1 secondary implant. The size of the implants varied from 18 to 23 mm diameter. The reason for explantation was exposure in all the 6 cases with additional infection in 2 cases. Histopathology revealed complete vascularization up to the core of the implant in all the cases. There was evidence of chronic inflammation within all the explanted specimens. Acute inflammation was present at the site of exposure in four of the implants. Three of these implants had additional evidence of necrosis. Two cases with clinically evident infection had Gram positive cocci within the implant. Foreign-body type giant-cells, melanophages and haemosiderin laden macrophages were also observed. Eviscerated specimens showed scleral remodelling and thickening.

CONCLUSION

All the implants were vascularized up to the core. There was histologic evidence of chronic inflammation in all the explanted implants possibly indicating the foreign nature of the implant material. The sclera did not impede vascularization of the implants in eviscerated specimens. We found no difference in the degree of vascularization of the implant in enucleated versus eviscerated implants.

[Exposure of orbital implants: causes and treatment]

The paper provides the results of a 15-year following-up of 91 patients with exposed orbital implants made from synthetic and biological materials. Surgery was made in the patients treated at different health care facilities. The authors analyze the causes of implant exposure in different periods. Early after surgery the most common causes of implant exposure are surgical equipment failure (inadequate implant coating with adjacent tissues), a too large implant arching the tissues, and mismatch of an artificial eye. In the late period, the more common cause is secondary infection or the toxic properties ofa material itself, which cause a persistent chronic inflammatory reaction. Moreover, the authors consider the mechanism of implant exposure and rejection depending on the material of an implant. The paper describes medical and surgical treatments in patients of this group.

Exposure Rate of Hydroxyapatite Orbital Implants

OBJECTIVE

To document the long-term experience with hydroxyapatite (HA) orbital implants (Bio-Eye) and analyze the factors influencing implant exposure, including surgical type, procedural modification, use of different wrapping materials and peg materials.

DESIGN

Retrospective observational case series.

PARTICIPANTS

Eight hundred two eyes from 802 patients who underwent anophthalmic socket surgery (eviscerations, enucleations, secondary implant placements) using HA implants, performed by one surgeon between May 1990 and December 2005.

METHODS

All patients' clinical records were reviewed. Baseline age, cause of anophthalmic surgery, surgical type, size of HA implant, wrapping material, and peg system were recorded.

MAIN OUTCOME MEASURES

Postoperative complications, especially implant exposure, were recorded separately before and after pegging, and compared according to type of surgery, wrapping material, and peg system.

RESULTS

The main cause of anophthalmic surgery was trauma (73%). A variety of wrapping materials have been used, including Tutoplast-dura, Vicryl mesh, autogenous sclera, and polyester-urethane. Implant exposure occurred in 17 patients (2.1%) before pegging and 14 (4.0%) after pegging. The exposure rate was significantly higher in eyes eviscerated without (7.2%) than with (1.1%) keratectomy (P = 0.018), but did not differ according to type of surgery (P = 0.710). When distributed according to 5-year periods, the exposure rate was higher from 1990 to 1994 (4.7%) than in later periods (P = 0.004). In patients who underwent enucleation or secondary implantation, there was no difference in exposure rate between Tutoplast-dura- and Vicryl mesh-wrapped implants (P = 0.235). Among the 353 patients (44.0%) who underwent pegging, those who received titanium-pegged implants had a significantly lower incidence of peg extrusion (5.2%), major discharge (5.2%), and pyogenic granuloma (9.1%) than those with nonsleeved polymethyl methacrylate and sleeved polycarbonate peg materials (P<0.05).

CONCLUSIONS

Exposures associated with HA orbital implants decreased with the improvement of surgical technique over time and have been managed successfully, both before and after pegging. The incidence of peg-related complications have decreased since the introduction of the titanium peg system.

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.