3D Printing for Customized Bone Reconstruction in Spheno-Orbital Meningiomas: A Systematic Literature Review and Institutional Experience.

Background: The treatment of spheno-orbital meningiomas (SOMs) requires extensive bone resections, creating significant defects in a complex geometrical space. Bone reconstruction represents a fundamental step that optimizes long-term aesthetic and functional outcomes. In recent years, 3D printing technology has also been exploited for complex skull base reconstructions, but reports remain scarce. Methods: We retrospectively analyzed four consecutive patients who underwent SOM resection and one-step 3D PEEK customized reconstruction from 2019 to 2023. A systematic review of 3D printing customized implants for SOM was then performed. Results: All patients underwent a frontotemporal craniotomy, removal of SOM, and reconstruction of the superolateral orbital wall and pterional region. The aesthetic outcome was extremely satisfactory in all cases. No orbital implant malposition or infectious complications were documented. Eleven papers were included in the literature review, describing 27 patients. Most (23) patients underwent a single-stage reconstruction; in three cases, the implant was positioned to correct postoperative delayed enophthalmos. Porous titanium was the most used material (16 patients), while PEEK was used in three cases. Prosthesis malposition was described in two (7.4%) patients. Conclusions: Single-step reconstruction with a personalized 3D PEEK prosthesis represents a valid reconstruction technique for the treatment of SOMs with good aesthetic outcomes.

Tuning zinc content in wollastonite bioceramic endowing outstanding angiogenic and antibacterial functions beneficial for orbital reconstruction.

Prosthetic eye is indispensable as filler after enucleation in patients with anophthalmia, whereas there are still many complications including postoperative infection and eye socket depression or extrusion during the conventional artificial eye material applications. Some Ca-silicate biomaterials showed superior bioactivity but their biological stability in vivo limit the biomedical application as long-term or permanent implants. Herein we aimed to understand the physicochemical and potential biological responses of zinc doping in wollastonite bioceramic used for orbital implants. The wollastonite powders with different zinc dopant contents (CSi-Znx) could be fabricated as porous implants with strut or curve surface pore geometries (cubic, IWP) via ceramic stereolithography. The experimental results indicated that, by increasing zinc-substituting-Ca ratio (up to 9%), the sintering and mechanical properties could be significantly enhanced, and meanwhile the bio-dissolution in vitro and biodegradability in vivo were thoroughly inhibited. In particular, an appreciable angiogenic activity and expected antibacterial efficacy (over 90 %) were synergistically achieved at 9 mol% Zn dopant. In the back-embedding and enucleation and implantation model experiments in rabbits, the superior continuous angiogenesis was corroborated from the 2D/3D fibrovascular reconstruction in the IWP-pore CSi-Zn9 and CSi-Zn13.5 groups within very short time stages. Totally, the present silicate-based bioceramic via selective Zn doping could produce outstanding structural stability and bifunctional biological responses which is especially valuable for developing the next-generation implants with vascular insertion and fixation in orbital reconstruction prothesis.

Virtual reconstruction of orbital defects using Gaussian process morphable models.

PURPOSE: The conventional method to reconstruct the bone level for orbital defects, which is based on mirroring and manual adaptation, is time-consuming and the accuracy highly depends on the expertise of the clinical engineer. The aim of this study is to propose and evaluate an automated reconstruction method utilizing a Gaussian process morphable model (GPMM). METHODS: Sixty-five Computed Tomography (CT) scans of healthy midfaces were used to create a GPMM that can model shape variations of the orbital region. Parameter optimization was performed by evaluating several quantitative metrics inspired on the shape modeling literature, e.g. generalization and specificity. The reconstruction error was estimated by reconstructing artificial defects created in orbits from fifteen CT scans that were not included in the GPMM. The developed algorithms utilize the existing framework of Gaussian process morphable models, as implemented in the Scalismo software. RESULTS: By evaluating the proposed quality metrics, adequate parameters are chosen for non-rigid registration and reconstruction. The resulting median reconstruction error using the GPMM was lower (0.35 ± 0.16 mm) compared to the mirroring method (0.52 ± 0.18 mm). In addition, the GPMM-based reconstruction is automated and can be applied to large bilateral defects with a median reconstruction error of 0.39 ± 0.11 mm. CONCLUSION: The GPMM-based reconstruction proves to be less time-consuming and more accurate than reconstruction by mirroring. Further validation through clinical studies on patients with orbital defects is warranted. Nevertheless, the results underscore the potential of GPMM-based reconstruction as a promising alternative for designing patient-specific implants.

Delayed Orbital Floor Reconstruction Using Mirroring Technique and Patient-Specific Implants: Proof of Concept.

Enophthalmos is a severe complication of primary reconstruction following orbital floor fractures, oncological resections, or maxillo-facial syndromes. The goal of secondary orbital reconstruction is to regain a symmetrical globe position to restore function and aesthetics. In this article, we present a method of computer-assisted orbital floor reconstruction using a mirroring technique and a custom-made titanium or high-density polyethylene mesh printed using computer-aided manufacturing techniques. This reconstructive protocol involves four steps: mirroring of the healthy orbit computer tomography files at the contralateral affected site, virtual design of a customized implant, computer-assisted manufacturing (CAM) of the implant using Direct Metal Laser Sintering (DMLS) or Computer Numerical Control (CNC) methods, and surgical insertion of the device. Clinical outcomes were assessed using 3dMD photogrammetry and computed tomography measures in 13 treated patients and compared to a control group treated with stock implants. An improvement of 3.04 mm (range 0.3-6 mm) in globe protrusion was obtained for the patients treated with patient-specific implants (PSI), and no major complications have been registered. The technique described here appears to be a viable method for correcting complex orbital floor defects needing delayed reconstruction.

Titanium Implants Coated with Hydroxyapatite Used in Orbital Wall Reconstruction-A Literature Review.

With the increasing incidences of orbital wall injuries, effective reconstruction materials and techniques are imperative for optimal clinical outcomes. In this literature review, we delve into the efficacy and potential advantages of using titanium implants coated with nanostructured hydroxyapatite for the reconstruction of the orbital wall. Titanium implants, recognized for their durability and mechanical strength, when combined with the osteoconductive properties of hydroxyapatite, present a potentially synergistic solution. The purpose of this review was to critically analyze the recent literature and present the state of the art in orbital wall reconstruction using titanium implants coated with nanostructured hydroxyapatite. This review offers clinicians detailed insight into the benefits and potential drawbacks of using titanium implants coated with nanostructured hydroxyapatite for orbital wall reconstruction. The highlighted results advocate for its benefits in terms of osseointegration and provide a novel strategy for orbital reconstruction, though further studies are essential to establish long-term efficacy and address concerns.

Charge-Transfer-Induced Interfacial Ferromagnetism in Ferromagnet-Free Oxide Heterostructures.

Due to the strong interlayer coupling between multiple degrees of freedom, oxide heterostructures have demonstrated exotic properties that are not shown by their bulk counterparts. One of the most interesting properties is ferromagnetism at the interface formed between "nonferromagnetic" compounds. Here we report on the interfacial ferromagnetic phase induced in the superlattices consisting of the two paramagnetic oxides CaRuO3 (CRO) and LaNiO3 (LNO). By varying the sublayer thickness in the superlattice period, we demonstrate that the ferromagnetic order has been established in both CaRuO3 and LaNiO3 sublayers, exhibiting an identical Curie temperature of ∼75 K. The X-ray absorption spectra suggest a strong charge transfer from Ru to Ni at the interface, triggering superexchange interactions between Ru/Ni ions and giving rise to the emergent ferromagnetic phase. Moreover, the X-ray linear dichroism spectra reveal the preferential occupancy of the d3z2-r2 orbital for the Ru ions and the dx2-y2 orbital for the Ni ions in the heterostructure. This leads to different magnetic anisotropy of the superlattices when they are dominated by CRO or LNO sublayers. This work clearly demonstrates a charge-transfer-induced interfacial ferromagnetic phase in the whole ferromagnet-free oxide heterostructures, offering a feasible way to tailor oxide materials for desired functionalities.

Clinical and radiographic assessment of patient-specific transantral reconstruction of orbital floor fractures: A case series.

To clinically and radiographically evaluate patient-specific titanium meshes via a trans-antral approach for correction of enophthalmos and orbital volume in patients with recent unilateral orbital floor fracture. Seven patients with unilateral orbital floor fractures received patient-specific titanium meshes that were designed based on a mirror-image of the contralateral intact orbit. The patient-specific implants (PSIs) were inserted via a trans-antral approach without endoscopic assistance. The patients were evaluated clinically for signs of diplopia and restricted gaze as well as radiographically for enophthalmos and orbital volume correction. Diplopia was totally resolved in two of the three patients who reported diplopia in the upward gaze. Whereas enophthalmos significantly improved in all but two patients, with a mean value of 0.2229 mm postoperatively compared to 0.9914 mm preoperatively. CT scans showed excellent adaptation of the PSIs to the orbital floor with a mean reduction of the orbital volume from 29.59 cc to 27.21 cc, a mean of 0.6% smaller than the intact orbit. It can be concluded that the proposed PSI can offer good reconstruction of the orbital floor through an isolated intraoral transantral approach with minimal complications. It could of special benefit in extensive orbital floor fractures.

Comparison of patient specific implant reconstruction vs conventional titanium mesh reconstruction of orbital fractures using a novel method.

To compare the reconstruction of orbital fractures using patient-specific implants (PSI) and conventional pre-formed titanium mesh; to develop a method of three-dimensional (3D) superimposition and analysis of the reconstructed orbits; and to present the pitfalls in 3D planning of orbital PSI and how to avoid them. This was a retrospective study of patients with orbital fractures who were treated in our institution between the years 2022 and 2023 using PSI or conservative prefabricated titanium mesh. Three different methods for virtual reconstruction of orbital fractures were used and are detailed with advantages, disadvantages and indications. Data acquired included age, gender, method of reconstruction, functional outcomes and aesthetic outcomes. 3D analysis for accuracy of reconstruction was performed. A total of 23 patients were included; 12 were treated using PSI and 11 using prefabricated titanium meshes. There were 8 male and 4 female patients in the PSI group comparted to 5 and 6 in the prefabricated group. All three virtual methods for reconstruction were used successfully, each with the proper indications. When comparing PSI reconstruction to conventional mesh, a significant difference in accuracy was observed; PSI cases showed an inaccuracy of 0.58 mm compared to 1.54 mm with the conventional method. Complications are presented, and tips for avoiding them are detailed. Three different methods for virtual reconstruction were used successfully; automated computerized reconstruction is used for small defects, repositioning is the superior method for non-comminuted cases while mirroring is the method of choice in comminuted fractures. 3D analysis can be performed using a novel method detailed in this report. PSI reconstruction showed superior results, indicating it should be the method of choice when possible. Pitfalls are presented and approaches to prevent them are discussed. Orbital reconstruction is a very important entity in maxillofacial surgery with crucial functional and esthetical implications, and one should use virtual planning and PSI implants, as they significantly improve outcomes.

Late correction of orbital deformities using customized 3D implant / Corrección tardía de deformidades de órbita usando implantes personalizados 3D

SUMMARY: Late orbital reconstruction is a complex and challenge for surgeons. The aim of this article is to present complex orbital reconstruction using patient specific implant (PSI) strategy and polyetheretherketone (PEEK). A literature review and a cases series of sequelae after complex orbital trauma are presented; cases with great middle third deformities showing defect in the maxilla, nasal area, body of the zygoma and zygomatic arch were included; in both cases the sequelae was for more than 10 years. Virtual planning and PEEK implants were manufacture using a puzzle (two or three parts) by 3D print or injection. Patients were treated and their surgeries carried out without complications, using a minimal surgical approach. No infections were observed, and after 12 months follow-up they were stable showing normal function. PSI based-PEEK for orbital reconstruction are safe, efficient, effective and to obtain orbital morphology with low complications.

RESUMEN: La reconstrucción tardía de la órbita es un desafío complejo para cirujanos. El objetivo de este artículo fue presentar la reconstrucción orbitaria compleja utilizando implante paciente específico (PSI) y polietereterketona (PEEK). Son presentados una revisión de literatura y una serie de casos con secuelas posteriores a un trauma orbitario complejo; además, son presentados casos con gran deformidad del tercio medio del rostro mostrando defectos en maxila, área nasal, cuerpo del hueso cigomático y arco cigomático; ambos casos de secuela fueron por más de 10 años. Planificación virtual e implantes en PEEK fueron creados usando una estrategia de puzzle (dos o tres partes) por inyección o impresión 3D. Los pacientes fueron tratados y sus cirugías realizadas sin complicaciones usando accesos quirúrgicos reducidos. No se observaron infecciones y después de 12 meses de seguimiento permanecieron estables mostrando función normal. Los PSI para reconstrucción orbitaria son seguros, eficientes, efectivos y recuperan morfología de órbita con bajas complicaciones.

Tissue repair after orbital reconstruction using polypropylene mesh implants: A histological study in dogs / Reparo tecidual após reconstrução de órbita com implante de malha de polipropileno: um estudo histológico em cães

Purpose: This experimental study aimed to assess the histological outcomes of orbit reconstruction with a polypropylene mesh implant in an animal model using dogs. Methods: The right and left orbits of 12 dogs were fractured in order to simulate orbital fractures similar to those occurring in humans as a result of trauma. The orbits were reconstructed with a polypropylene mesh positioned approximately 10 mm beyond the bone defect borders. The 24 orbits were divided into four groups of six: one group was given one polypropylene mesh layer; another group received two layers; a third group was given three polypropylene mesh layers; and the fourth group did not receive any implant (control group). The dogs were divided into clusters of four animals and were euthanized 15, 30, or 60 days after the surgery. The orbit medial wall was removed, and samples were subjected to histological polypropylene mesh analysis by optical microscopy. Data were analyzed using a non-parametric test with a 5% level of significance. Results: It was found that the polypropylene mesh caused a mild to moderate tissular reaction. Conclusion: The implant was well tolerated even with two or three overlapping layers.

Objetivo: Trata-se de estudo experimental em que se reconstruíram os continentes orbitais de 12 cães com implante de tela de polipropileno. Metodologia: Os continentes orbitais foram fraturados simulando as fraturas orbitais que ocorrem em humanos devido ao trauma e reconstruídas com tela de polipropileno cortadas com extensão de cerca de 10mm além da margem do defeito ósseo. Utilizaram-se uma, duas ou três camadas de tela de polipropileno nas órbitas teste e algumas órbitas, somente fraturadas, serviram como controle. Os cães foram sacrificados nos tempos de 15, 30 e 60 dias de pós-operatório; os tecidos das órbitas teste e controle foram removidos e preparados para análise histológica em microscopia óptica. Os resultados obtidos pela análise histológica foram submetidos a análise estatística não paramétrica com 5% de significância. Resultados: A tela de polipropileno causou reação tecidual de leve a moderada nos tecidos. Conclusão: O implante foi bem tolerado, mesmo quando a tela foi superposta em duas ou três camadas.