Patient-specific implants in orbital reconstruction.

PURPOSE OF REVIEW: Advances in the use of patient-specific implants (PSIs) and virtual surgical planning (VSP) for reconstruction of primary and secondary traumatic orbital defects are explored. RECENT FINDINGS: PSIs and VSP are emerging technologies that promise to make complex orbital reconstructions safer and more predictable for patients. Recent studies highlight principles of implant design, the novel use of multiunit implant constructs, and utility of intraoperative imaging adjuncts to achieve favorable outcomes. SUMMARY: This article summarizes recent developments in PSIs for orbital reconstruction. A complete workflow including presurgical planning, execution in the operating room, postoperative analysis, and avoidance of common pitfalls and implant design errors are reviewed.

A three-dimensional printed photopolymer resin implant for orbital rehabilitation for evisceration / Implante de resina fotocurável para evisceração produzido por impressora tridimensional

ABSTRACT Purpose: To evaluate the biocompatibility of three-dimensional (3D) printed orbital spheres for evisceration. Materials: A total of 10 consecutive patients (eight females and two males; mean age, 46.8 ± 14.2 years) underwent evisceration of blind painful eyes. 3D spherical implants produced by a rapid prototype machine were used to restore orbital volume. The implants were produced from a commercially available photocurable resin (Fullcure®). Systemic toxicity was evaluated by comparing serum biochemical measurements (creatine phosphokinase, aspartate aminotransferase, alanine aminotransferase, albumin, creatinine, urea, alkaline phosphatase, and C-reactive protein) before and at 12 months after surgery. Local toxicity was assessed by the evaluation of signs of socket inflammation at the first postoperative month. Changes in implant size were determined by computed tomography scans at 2 and 12 months after surgery. Results: The postoperative evaluations were uneventful. The biochemical evaluation showed no significant changes after surgery. None of the patients presented signs of orbital implant inflammation, infection, exposure, or extrusion. Computed tomography scan evaluations revealed no changes in implant size. Conclusion: To the best of our knowledge, this is the first phase-1 clinical study to certify the biocompatibility of the Fullcure resin for orbital implants in humans. The 3D printing technology permits fast and accurate production of implants for this purpose.

RESUMO Objetivos: Avaliar a biocompatibilidade das esferas produzidas por impressora tridimensional em evisceração. Pacientes e métodos: Evisceração por olho cego doloroso foi realizada em 10 pacientes consecutivos (8 mulheres, idade média: 46.8 ± 14.2 anos). Os implantes esféricos foram produzidos pelo sistema de prototipagem rápida utilizando dados tridimensionais computadorizados. O material utilizado para produção dos implantes foi a resina fotocurável Fullcure®. A avaliação da toxicidade sistêmica do material foi realizada por meio da dosagem de marcadores bioquímicos (creatina fosfoquinase, aspartato aminotransferase, alanina aminotransferase, albumina, creatinina, ureia, fosfatase alcalina, e proteína C-reactiva) antes da cirurgia e aos 12 meses de pós-operatorio. A avaliação da toxicidade local foi realizada por meio do registro qualitativo dos sinais inflamatórios no lado operado durante o primeiro mês de pós-operatório. O tamanho dos implantes foi medido em tomografias computadorizadas (CT) aos 2 e 12 meses de pós-operatório. Resultados: A avaliação bioquímica mostrou que os marcadores estudados não sofreram alterações significativas após a cirurgia. Nenhum paciente apresentou sinais de inflamação atípica, infecção, exposição ou extrusão. A avaliação tomográfica não demonstrou mudanças nos tamanhos dos implantes. Conclusão: O presente trabalho é o primeiro estudo clínico realizado para atestar a biocompatibilidade dos implantes orbitais de resina fotocurável Fullcure. A produção dos implantes pela técnica de impressão tridimensional, utilizando essa resina, permite a disponibilização rápida e acurada do produto final

A three-dimensional printed photopolymer resin implant for orbital rehabilitation for evisceration.

PURPOSE: To evaluate the biocompatibility of three-dimensional (3D) printed orbital spheres for evisceration. MATERIALS: A total of 10 consecutive patients (eight females and two males; mean age, 46.8 ± 14.2 years) underwent evisceration of blind painful eyes. 3D spherical implants produced by a rapid prototype machine were used to restore orbital volume. The implants were produced from a commercially available photocurable resin (Fullcure®). Systemic toxicity was evaluated by comparing serum biochemical measurements (creatine phosphokinase, aspartate aminotransferase, alanine aminotransferase, albumin, creatinine, urea, alkaline phosphatase, and C-reactive protein) before and at 12 months after surgery. Local toxicity was assessed by the evaluation of signs of socket inflammation at the first postoperative month. Changes in implant size were determined by computed tomography scans at 2 and 12 months after surgery. RESULTS: The postoperative evaluations were uneventful. The biochemical evaluation showed no significant changes after surgery. None of the patients presented signs of orbital implant inflammation, infection, exposure, or extrusion. Computed tomography scan evaluations revealed no changes in implant size. CONCLUSION: To the best of our knowledge, this is the first phase-1 clinical study to certify the biocompatibility of the Fullcure resin for orbital implants in humans. The 3D printing technology permits fast and accurate production of implants for this purpose.

Survival Analysis of Orbital Implants and Potential Influencing Factors: A Retrospective Long-Term Study.

PURPOSE: Application of endosseous implants in prosthetic orbital reconstruction seems to be very successful, but few reports have evaluated cumulative survival rates of orbital implants over a long period. The aim of this study was to analyze long-term survival rates and potential influencing factors of orbital implants. MATERIALS AND METHODS: A retrospective evaluation of patients treated with extraoral screw implants for retaining orbital prostheses from 1991 to 2014 was performed. Patient records were assessed for implant survival, demographic data, defect etiology, irradiation status, location of implant placement, implant systems, length, and retention type. Data were analyzed using the Kaplan-Meier method and log-rank test to compare survival curves. RESULTS: A total of 282 orbital implants placed in 78 patients were evaluated during an observation period ranging from 2 to 268 months (mean: 94.97 months). The cumulative implant survival rate was 91.3% at 2 years, 80.5% at 5 years, 68.7% at 10 years, and 62.2% after 15 years. The survival rate was significantly higher in females (75.3%) vs males (47.3%), in supraorbital vs infraorbital implants (67.4% vs 51.5%), and in Brånemark implants (70.2%) vs Straumann implants (54.5%). CONCLUSION: The presented data suggest that the long-term predictability of orbital implants revealed good to acceptable results. Factors such as female gender, localization in the supraorbital rim, a machined surface of the implant system, length, and magnetic retention seem to affect the implant survival rate positively, whereas irradiation status does not show any influence. These factors should be considered in planning future patient rehabilitation.

Temporary cosmetic painted prostheses in anophthalmic surgery: an alternative to early postoperative clear conformers.

PURPOSE: To evaluate the use and safety of temporary, cosmetic, painted prostheses as an alternative to clear conformers immediately post removal of eye or socket surgery in children and adults. PATIENTS AND METHODS: A 2-year, two-centre, retrospective audit of 54 patients undergoing enucleation, evisceration, secondary implant or socket reconstruction receiving a temporary painted prosthesis as an alternative to clear conformers immediately post surgery. Patient questionnaire and review of clinical notes was conducted for all patients. RESULTS: We reviewed 54 consecutive patients (22 females, 32 males, mean age 18.6 years, range 6 days to 82 years) who received cosmetic painted prostheses from January 2009 to December 2010. Procedures included: evisceration with primary implant (5), enucleation with primary implant (37), secondary implant (9), dermis fat graft (2) and fornix reconstruction with buccal graft (1). Complications included: pyogenic granuloma (2), mucous discharge (2) and exposure (2). All adults found their prosthesis comfortable, and no problems were reported by the parents of the children included in this study. In all, 46 patients (88% of respondents) returned to normal activities within 2 weeks. The temporary prosthesis fell out at least once in 25% of cases. In all, 90% of respondents expressed a definite preference towards the painted shell over a clear shell. CONCLUSION: Temporary cosmetic painted prostheses placed immediately after removal of the eye or socket surgery are well tolerated and preferred to standard clear shells. Painted prostheses, matched to the contralateral iris are a valuable option in anophthalmic surgery as an alternative to traditional clear conformers.

The effect of tissue wrapping on the expansion of hydrophilic orbital implants.

PURPOSE: Hydrogel implants have been used in hypoplastic orbital expansion. Advantages include insertion through a small incision and expansion without manipulation. The rapid rate of expansion, however, may lead to undesirable outcomes, including implant migration. The authors evaluate the effect of tissue wrapping on expansion of hydrogel implants. METHODS: Three identical hydrogel implants were subjected to one of 3 in vitro interventions: unwrapped control, porcine scleral-wrapped, and porcine fascia-wrapped. Each implant was submerged in normal saline solution. Diameter and volume were measured hourly for 24 hours and then every 4 hours until a plateau or maximal weight was achieved. Measurements were plotted with time as the independent variable and the above measurements as dependent variables. In addition, the best exponential function was graphed and the area under the curve was calculated. RESULTS: Linear plots of data showed a reduction in the rate of diameter and volume expansion for wrapped implants. The areas under the curve of the best-fit exponential function were less for both scleral- and fascia-wrapped implants. Fascia wrapping slowed the rate of volume expansion more than sclera. Also, fascia wrapping seemed to significantly reduce the final implant diameter and volume. CONCLUSIONS: Tissue wrapping slows the rate of expansion of hydrogel spheres in vitro. Fascia wrapping may also reduce the final implant size.

Development of a poly(2-hydroxyethyl methacrylate) orbital implant allowing direct muscle attachment and tissue ingrowth.

PURPOSE: To develop a poly(2-hydroxyethyl methacrylate) orbital implant that allows tissue ingrowth and direct muscle attachment to minimize the risk of extrusion and to enhance cosmesis. METHODS: Assessment of clinical outcomes and histologic findings after implantation of 18 prototype prostheses into rabbits. The implants were not wrapped with other tissues or materials. RESULTS: One case of infection was observed but there were no extrusions, with up to 21 months follow-up. Biocolonization was confirmed histologically. Good movement was observed when a cosmetic shell was fitted. CONCLUSIONS: The prototype prosthesis appears promising, with particular advantages being the direct attachment of extraocular muscles, good cosmesis and movement, and a low complication rate in this pilot study.

Predicting the ideal implant size before enucleation.

PURPOSE: This study of volume replacement in anophthalmic sockets compares the volume replaced by the implant and prosthesis with the volume removed from the socket and evaluates A-scan ultrasonography as a tool to predict an ideal implant size before enucleation. METHODS: In this retrospective study of 59 anophthalmic patients, the volume replaced by the implant and the prosthesis was compared with the volume of the enucleated eye. The volume removed was estimated by calculating the volume of the fellow eye using A-scan ultrasonography. Enophthalmos and superior sulcus deformity were measured and correlated with the percent volume replacement in the anophthalmic sockets. RESULTS: Greater enophthalmos and superior sulcus deformity were found in patients with less than 100% volume replacement compared with those with 100% or more volume replacement. The axial length determined by A-scan ultrasonography of the fellow eye suggested that a larger implant size should have been placed in 76.3% of those patients with less than 100% volume replacement. Sixty-three percent of adult patients could have received an implant more than 22 mm in diameter to fill 80% of the volume removed at enucleation. CONCLUSIONS: A-scan ultrasonography of the fellow eye provides a useful tool for predicting the implant size before surgery for optimal volume replacement.