Orbital Wall Reconstruction with Two-Piece Puzzle 3D Printed Implants: Technical Note

Towards Precision Ophthalmology: The Role of 3D Printing and Bioprinting in Oculoplastic Surgery, Retinal, Corneal, and Glaucoma Treatment

In the forefront of ophthalmic innovation, biomimetic 3D printing and bioprinting technologies are redefining patient-specific therapeutic strategies. This critical review systematically evaluates their application spectrum, spanning oculoplastic reconstruction, retinal tissue engineering, corneal transplantation, and targeted glaucoma treatments. It highlights the intricacies of these technologies, including the fundamental principles, advanced materials, and bioinks that facilitate the replication of ocular tissue architecture. The synthesis of primary studies from 2014 to 2023 provides a rigorous analysis of their evolution and current clinical implications. This review is unique in its holistic approach, juxtaposing the scientific underpinnings with clinical realities, thereby delineating the advantages over conventional modalities, and identifying translational barriers. It elucidates persistent knowledge deficits and outlines future research directions. It ultimately accentuates the imperative for multidisciplinary collaboration to enhance the clinical integration of these biotechnologies, culminating in a paradigm shift towards individualized ophthalmic care.

The Use of Functional Biomaterials in Aesthetic and Functional Restoration in Orbital Surgery

The integration of functional biomaterials in oculoplastic and orbital surgery is a pivotal area where material science and clinical practice converge. This review, encompassing primary research from 2015 to 2023, delves into the use of biomaterials in two key areas: the reconstruction of orbital floor fractures and the development of implants and prostheses for anophthalmic sockets post-eye removal. The discussion begins with an analysis of orbital floor injuries, including their pathophysiology and treatment modalities. It is noted that titanium mesh remains the gold standard for orbital floor repair due to its effectiveness. The review then examines the array of materials used for orbital implants and prostheses, highlighting the dependence on surgeon preference and experience, as there are currently no definitive guidelines. While recent innovations in biomaterials show promise, the review underscores the need for more clinical data before these new materials can be widely adopted in clinical settings. The review advocates for an interdisciplinary approach in orbital surgery, emphasizing patient-centered care and the potential of biomaterials to significantly enhance patient outcomes.

Trans-mastoid anchorage as a novelty in glenoid fossa reconstruction for hemifacial microsomia with agenesis of zygomatic arch and external acoustic meatus-Technical note with a case illustration

Total joint reconstruction (TJR) has become the most preferred method of reconstruction in recent years for hemifacial microsomia (HFM). This requires meticulous planning for the glenoid fossa and ramus prosthesis along with the arch in certain indications. TJR in a type V HFM is extremely challenging due to agenesis/hypolasia of the zygoma and arch which compromises anchorage of the glenoid prosthesis. Conventional options used for such indications incorporate extended designs for the fossa. However, the two designs used commonly are associated with limitations; (i) the temporal extension is overtly large and cannot be anchored in patients with thin temporal bone and (ii) the glenoid fossa incorporated into the arch prosthesis, where the fossa is not positioned on stable bone and occlusal loading is non-physiological; transmitted onto the arch prosthesis rather than the skull base. The authors propose the use of the mastoid process as an alternative for anchorage of fossa prosthesis. This technique offers stable anchorage while facilitating ideal positioning on the skull base for optimal masticatory load transmission. The case illustration depicts reconstruction of the TMJ, zygoma and the zygomatic arch in a 31-year-old man with type V HFM, with a three-year follow-up, with good clinical outcomes sans complications.

Orbital Reconstruction Using a Polyetheretherketone Patient-Specific Implant After Removal of a Mucocele Developing After Orbital Fracture Repair

A few mucoceles developing secondary to facial bone fractures have been reported. Mucocele formation is thought to be attributable to displacement of the respiratory mucosa with obstruction of the sinus opening, especially if untreated. Accurate diagnosis and management are required; a growing mucocele will gradually destroy adjacent bony structures and cause irreversible complications. The authors describe a patient who presented with diplopia and mild discomfort when gazing upward. She had undergone reconstruction of medial and inferior orbital fractures 20 years previously. The patient was diagnosed with a mucocele developing after orbital fracture repair. The patient underwent mucocele removal and orbital reconstruction using a polyetheretherketone patient-specific implant. In a patient with orbital symptoms but without acute trauma, a mucocele should be among the differential diagnoses if history-taking reveals past orbital trauma and surgery. A polyetheretherketone patient-specific implant was effective for orbital reconstruction after mucocele removal.

Assessing Leachable Cytotoxicity of 3D-Printed Polymers and Facile Detoxification Methods

Additive manufacturing of polymers is gaining momentum in health care industries by providing rapid 3D printing of customizable designs. Yet, little is explored about the cytotoxicity of leachable toxins that the 3D printing process introduced into the final product. We studied three printable materials, which have various mechanical properties and are widely used in stereolithography 3D printing. We evaluated the cytotoxicity of these materials through exposing two fibroblast cell lines (human and mouse derived) to the 3D-printed parts, using overlay indirect contact assays. All the 3D-printed parts were measured toxic to the cells in a leachable manner, with flexible materials more toxic than rigid materials. Furthermore, we attempted to reduce the toxicity of the 3D-printed material by employing three treatment methods (further curing, passivation coating, and Soxhlet solvent extraction). The Soxhlet solvent extraction method was the most effective in removing the leachable toxins, resulting in the eradication of the material's toxicity. Passivation coating and further curing showed moderate and little detoxification, respectively. Additionally, mechanical testing of the materials treated with extraction methods revealed no significant impacts on its mechanical performances. As leachable toxins are broadly present in 3D-printed polymers, our cytotoxicity evaluation and reduction methods could aid in extending the selections of biocompatible materials and pave the way for the translational use of 3D printing.

Personalized Medicine Workflow in Post-Traumatic Orbital Reconstruction

Restoration of the orbit is the first and most predictable step in the surgical treatment of orbital fractures. Orbital reconstruction is keyhole surgery performed in a confined space. A technology-supported workflow called computer-assisted surgery (CAS) has become the standard for complex orbital traumatology in many hospitals. CAS technology has catalyzed the incorporation of personalized medicine in orbital reconstruction. The complete workflow consists of diagnostics, planning, surgery and evaluation. Advanced diagnostics and virtual surgical planning are techniques utilized in the preoperative phase to optimally prepare for surgery and adapt the treatment to the patient. Further personalization of the treatment is possible if reconstruction is performed with a patient-specific implant and several design options are available to tailor the implant to individual needs. Intraoperatively, visual appraisal is used to assess the obtained implant position. Surgical navigation, intraoperative imaging, and specific PSI design options are able to enhance feedback in the CAS workflow. Evaluation of the surgical result can be performed both qualitatively and quantitatively. Throughout the entire workflow, the concepts of CAS and personalized medicine are intertwined. A combination of the techniques may be applied in order to achieve the most optimal clinical outcome. The goal of this article is to provide a complete overview of the workflow for post-traumatic orbital reconstruction, with an in-depth description of the available personalization and CAS options.

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.

Secondary Correction of Posttraumatic Enophthalmos

Posttraumatic enophthalmos (PE) arises when the ocular globe is displaced posteriorly and inferiorly in the orbital cavity due to a mismatch in orbital volume and orbital content. This most commonly happens after orbital fractures. The resulting disruptions to aesthetic form and ocular functions often necessitate surgical correction for reconstruction and restoration. The purpose of surgical management of PE is to reconstruct orbital shape and volume as well as to restore any herniated orbital content. This can be particularly challenging in cases involving large defects that require complex orbital reconstruction. Recent advancements in computer-aided surgery have introduced innovative and important tools to assist surgeons with these difficult cases. The ability to create customized, patient-specific implants can facilitate reconstruction involving complicated anatomy. Additionally, intraoperative imaging and intraoperative navigation can serve as useful guides for surgeons to more accurately place implants, especially in cases with limited visualization, in order to achieve optimal outcomes.

Effect of Surface Tooling Techniques of Medical Titanium Implants on Bacterial Biofilm Formation In Vitro

The aim of this study was to assess the biofilm formation of Streptococcus mutans, Staphylococcus aureus, Enterococcus faecalis, and Escherichia coli on titanium implants with CAD-CAM tooling techniques. Twenty specimens of titanium were studied: Titanium grade 2 tooled with a Planmeca CAD-CAM milling device (TiGrade 2), Ti6Al4V grade 5 as it comes from CAD-DMLS device (computer aided design-direct metal laser sintering device) (TiGrade 5), Ti6Al4V grade 23 as it comes from a CAD-CAM milling device (TiGrade 23), and CAD-DMLS TiGrade 5 polished with an abrasive disc (TiGrade 5 polished). Bacterial adhesion on the implants was completed with and without saliva treatment to mimic both extraoral and intraoral surgical methods of implant placement. Five specimens/implant types were used in the bacterial adhesion experiments. Autoclaved implant specimens were placed in petri plates and immersed in saliva solution for 30 min at room temperature and then washed 3×with 1 ×PBS. Bacterial suspensions of each strain were made and added to the specimens after saliva treatment. Biofilm was allowed to form for 24 h at 37 °C and the adhered bacteria was calculated. Tooling techniques had an insignificant effect on the bacterial adhesion by all the bacterial strains studied. However, there was a significant difference in biofilm formation between the saliva-treated and non-saliva-treated implants. Saliva contamination enhanced S. mutans, S. aureus, and E. faecalis adhesion in all material types studied. S. aureus was found to be the most adherent strain in the saliva-treated group, whereas E. coli was the most adherent strain in the non-saliva-treated group. In conclusion, CAD-CAM tooling techniques have little effect on bacterial adhesion. Saliva coating enhances the biofilm formation; therefore, saliva contamination of the implant must be minimized during implant placement. Further extensive studies are needed to evaluate the effects of surface treatments of the titanium implant on soft tissue response and to prevent the factors causing implant infection and failure.

Biocompatible Materials for Orbital Wall Reconstruction-An Overview

The reconstruction of an orbit after complex craniofacial fractures can be extremely demanding. For satisfactory functional and aesthetic results, it is necessary to restore the orbital walls and the craniofacial skeleton using various types of materials. The reconstruction materials can be divided into autografts (bone or cartilage tissue) or allografts (metals, ceramics, or plastic materials, and combinations of these materials). Over time, different types of materials have been used, considering characteristics such as their stability, biocompatibility, cost, safety, and intraoperative flexibility. Although the ideal material for orbital reconstruction could not be unanimously identified, much progress has been achieved in recent years. In this article, we summarise the advantages and disadvantages of each category of reconstruction materials. We also provide an update on improvements in material properties through various modern processing techniques. Good results in reconstructive surgery of the orbit require both material and technological innovations.

3D Printing in Eye Care

Three-dimensional printing enables precise modeling of anatomical structures and has been employed in a broad range of applications across medicine. Its earliest use in eye care included orbital models for training and surgical planning, which have subsequently enabled the design of custom-fit prostheses in oculoplastic surgery. It has evolved to include the production of surgical instruments, diagnostic tools, spectacles, and devices for delivery of drug and radiation therapy. During the COVID-19 pandemic, increased demand for personal protective equipment and supply chain shortages inspired many institutions to 3D-print their own eye protection. Cataract surgery, the most common procedure performed worldwide, may someday make use of custom-printed intraocular lenses. Perhaps its most alluring potential resides in the possibility of printing tissues at a cellular level to address unmet needs in the world of corneal and retinal diseases. Early models toward this end have shown promise for engineering tissues which, while not quite ready for transplantation, can serve as a useful model for in vitro disease and therapeutic research. As more institutions incorporate in-house or outsourced 3D printing for research models and clinical care, ethical and regulatory concerns will become a greater consideration. This report highlights the uses of 3D printing in eye care by subspecialty and clinical modality, with an aim to provide a useful entry point for anyone seeking to engage with the technology in their area of interest.

Technical Note on Three- and Four-Wall Orbital Reconstructions with Patient-Specific Implants

ABSTRACT

Orbital reconstruction is one of the most complex procedures in maxillofacial surgery. It becomes even more complex when all references to the original anatomy are lost. The purpose of this article is to provide an overview of techniques for complex three- and four-wall orbital reconstructions. Preoperative virtual surgical planning is essential when considering different reconstruction possibilities. The considerations that may lead to different approaches are described, and the advantages and drawbacks of each technique are evaluated. It is recommended to reconstruct solitary three-wall or four-wall orbital defects with multiple patient-specific implants. Optimizations of this treatment protocol are suggested, and their effects on predictability are demonstrated in a case presentation of a four-wall defect reconstruction with multiple patient-specific implants.

Custom Interlocking Implants for Primary and Secondary Reconstruction of Large Orbital Floor Defects: Case Series and Description of Workflow

Large fractures of the orbital floor present several technical challenges for the craniomaxillofacial surgeon. One major challenge is limited surgical access as it pertains to the adaption of a large implant within the confines of a small incision. Transfacial approaches or techniques to extend the incision may improve access but have the potential drawback of creating unesthetic scars, nerve injury, and lid contracture. In this series we present a novel solution combining virtual surgical planning and the use of a 2 piece, interlocking patient specific implant to address the problem of limited surgical access.

A Multi-Criteria Assessment Strategy for 3D Printed Porous Polyetheretherketone (PEEK) Patient-Specific Implants for Orbital Wall Reconstruction

Pure orbital blowout fractures occur within the confines of the internal orbital wall. Restoration of orbital form and volume is paramount to prevent functional and esthetic impairment. The anatomical peculiarity of the orbit has encouraged surgeons to develop implants with customized features to restore its architecture. This has resulted in worldwide clinical demand for patient-specific implants (PSIs) designed to fit precisely in the patient's unique anatomy. Material extrusion or Fused filament fabrication (FFF) three-dimensional (3D) printing technology has enabled the fabrication of implant-grade polymers such as Polyetheretherketone (PEEK), paving the way for a more sophisticated generation of biomaterials. This study evaluates the FFF 3D printed PEEK orbital mesh customized implants with a metric considering the relevant design, biomechanical, and morphological parameters. The performance of the implants is studied as a function of varying thicknesses and porous design constructs through a finite element (FE) based computational model and a decision matrix based statistical approach. The maximum stress values achieved in our results predict the high durability of the implants, and the maximum deformation values were under one-tenth of a millimeter (mm) domain in all the implant profile configurations. The circular patterned implant (0.9 mm) had the best performance score. The study demonstrates that compounding multi-design computational analysis with 3D printing can be beneficial for the optimal restoration of the orbital floor.

3D Printing for Medical Applications: Current State of the Art and Perspectives during the COVID-19 Crisis

The coronavirus SARS-CoV-2 pandemic has affected over one hundred million people worldwide and has resulted in over two million deaths. In addition to the toll that coronavirus takes on the health of humans infected with the virus and the potential long term effects of infection, the repercussions of the pandemic on the economy as well as on the healthcare system have been enormous. The global supply of equipment necessary for dealing with the pandemic experienced extreme stress as healthcare systems around the world attempted to acquire personal protective equipment for their workers and medical devices for treating COVID-19. This review describes how 3D printing is currently being used in life saving surgeries such as heart and lung surgery and how 3D printing can address some of the worldwide shortage of personal protective equipment, by examining recent trends of the use of 3D printing and how these technologies can be applied during and after the pandemic. We review the use of 3D printed models for treating the long term effects of COVID-19. We then focus on methods for generating face shields and different types of respirators. We conclude with areas for future investigation and application of 3D printing technology.

Going beyond the limitations of the non-patient-specific implant in titanium reconstruction of the orbit

Reconstruction of post traumatic orbital defects has undergone a stepwise evolution following developments in reconstructive materials and surgical techniques. Advances in communication between surgical teams and design technicians have allowed provision of bespoke surgical plates with a high degree of accuracy and surgical relevance in an appropriate timeframe. We present a case series of 41 consecutive patients treated in London and BernBern Switzer between March 2019 and September 2020 with extensive defects reconstructed with patient specific orbital plates. Complexity of fracture was risk adjusted using the Jaquiery scale with one patient (J3), 14 patients (J4), and 26 Patients (J5). Outcome was assessed by accuracy of fit at the surgical margins and was 94.5%. The study group was statistically tested against a previous series by the same group and was statistically different with respect to the case complexity (p<0.001) and accuracy of fit (p<0.001) (Fisher's exact test). Complications included the removal on one plate due to patient choice, with perfect surgical position and resolving diplopia. Only one plate articulation was poor, this mitigated by the size of the defect and the orbital soft tissue swelling which prohibited seating the implant. The patient remains well with acceptable function and satisfactory aesthetics. We present design considerations including the use two part plates, and surgical pearls to achieve predictable placement. We believe that the use of custom plates for reconstruction of Jaquiery 4 and 5 should be considered. We regard this technology as a game changer in surgical management of the complex high risk orbit.

Reconstruction of Combined Orbital Floor and Medial Wall Fractures Using Custom-Made Titanium Alloy Implant

ABSTRACT

The reconstruction of combined orbital floor and medial wall fractures is challenging due to the surgical approach and implant stability. A 0.5 mm thickness rigidity custom made titanium alley implant was created by 3-dimensional printing with electron-beam additive manufacturing. The implant was designed to cover the entire surface of the inferomedial orbit based on the flipped the contralateral orbit images. Although the cost was expensive, the use of three-dimensional printed implants for extensive orbital wall fractures was useful for decreasing operative time, and can be accessed with a limited surgical approach with a precise fit.

Customized Orbit and Frontal Bone Implants

Orbitocranial reconstruction objectives include creation of a solid barrier between intracranial contents and the environment allowing restoration of physiologic homeostasis and restoration of aesthetic craniofacial contours. Historically, bone grafts have been used for reconstruction but were fraught with unpredictable resorption and imperfect contouring given the complex anatomy of the orbitofrontal bones. With advances in three-dimensional modeling technology, alloplastic custom implants in orbital and frontal bone reconstruction have allowed for rapid fixation reducing surgical times and improved cosmesis.

Clinical efficacy of peek patient-specific implants in orbital reconstruction

Purpose

To assess the clinical efficacy of custom made PEEK patient-specific implants in treatment of orbital wall defects.

Methods

Forty-five patients with unilateral post-traumatic orbital wall defects were enrolled in the study. They underwent subsequent reconstructive procedures using PEEK patient-specific implants (PSI) or pre-bent titanium plates. All the patients were examined with the standardized algorithm, including local status examination, vision assessment and computer tomography (CT) with measurements of the orbital volume. A comparative analysis of the treatment outcomes in two groups of patients (pre-bent plates/PSI) was performed.

Results

The study findings show an absence of any postoperative infection, inflamation or decreased visual acuity in either group. In PSI group, diplopia after surgery was absent in 82.1% of patients versus 70.6% of controls. The mean duration of surgery was 54.25 ± 16.8 min with PSI application and 82.9 ± 10.8 min with pre-bent plates. The mean difference between the intact and damaged orbital volume was 1.9 ± 1.4 cm³ in the control group versus 0.74 ± 0.6 cm³ in PSI group (р<0.05).

Conclusion

PEEK PSI demonstrated higher clinical efficacy in comparison to pre-bent plates in orbital wall reconstruction especially in restoring the volume and shape of the damaged orbit.

Reconstruction of Post-Traumatic Orbital Defects and Deformities with Custom-Made Patient-Specific Implants: Evaluation of the Efficacy and Clinical Outcome

The main purpose of this article is to evaluate the efficacy of patient-specific implants (PSI) in treatment of patients with post-traumatic orbital defects and deformities. Twenty-three patients with post-traumatic orbital defects and deformities, who underwent subsequent reconstructive procedures using PSI, were included in the study. All the patients were examined according to the standard algorithm involving the local status examination, vision assessment, and computed tomography before and after surgery. The study findings show neither postoperative infectious complications nor decreased visual acuity or loss of visual fields. Functional disorders resolved in 65.2% of cases 1 month after the surgical intervention and in 86.96% of patients within a 3-month term. Positive aesthetic outcomes were seen in 95.7% of cases. Reconstruction with computer-aided design/computer-aided manufactured PSI is an effective procedure that allows accurate restoring of the complex orbital anatomy.

Applications of three-dimensional printing in orbital diseases and disorders

PURPOSE OF REVIEW

To comprehensively review the applications of advanced three-dimensional printing technology in the management of orbital abnormalities.

RECENT FINDINGS

Three-dimensional printing has added value in the preoperative planning and manufacturing of patient-specific implants and surgical guides in the reconstruction of orbital trauma, congenital defects and tumor resection. In view of the costs and time, it is reserved as strategy for large and complex craniofacial cases, in particular those including the bony contour. There is anecdotal evidence of a benefit of three-dimensional printing in the manufacturing of prostheses for the exenterated and anophthalmic socket, and in the fabrication of patient-specific boluses, applicators and shielding devices for orbital radiation therapy. In addition, three-dimensional printed healthy and diseased orbits as phantom tangible models may augment the teaching and learning process of orbital surgery.

SUMMARY

Three-dimensional printing allows precision treatment tailored to the unique orbital anatomy of the patient. Advancement in technology and further research are required to support its wider use in orbital clinical practice.

Patient-specific puzzle implant preformed with 3D-printed rapid prototype model for combined orbital floor and medial wall fracture

BACKGROUND

The management of combined orbital floor and medial wall fractures involving the inferomedial strut is challenging due to absence of stable cornerstone. In this article, we proposed surgical strategies using customized 3D puzzle implant preformed with Rapid Prototype (RP) skull model.

METHODS

Retrospective review was done in 28 patients diagnosed with combined orbital floor and medial wall fracture. Using preoperative CT scans, original and mirror-imaged RP skull models for each patient were prepared and sterilized. In all patients, porous polyethylene-coated titanium mesh was premolded onto RP skull model in two ways; Customized 3D jigsaw puzzle technique was used in 15 patients with comminuted inferomedial strut, whereas individual 3D implant technique was used in each fracture for 13 patients with intact inferomedial strut. Outcomes including enophthalmos, visual acuity, and presence of diplopia were assessed and orbital volume was measured using OsiriX software preoperatively and postoperatively.

RESULTS

Satisfactory results were achieved in both groups in terms of clinical improvements. Of 10 patients with preoperative diplopia, 9 improved in 6 months, except one with persistent symptom who underwent extraocular muscle rupture. 18 patients who had moderate to severe enophthalmos preoperatively improved, and one remained with mild degree. Orbital volume ratio, defined as volumetric ratio between affected and control orbit, decreased from 127.6% to 99.79% (p < 0.05) in comminuted group, and that in intact group decreased from 117.03% to 101.3% (p < 0.05).

CONCLUSION

Our surgical strategies using the jigsaw puzzle and individual reconstruction technique provide accurate restoration of combined orbital floor and medial wall fractures.

Low-Cost 3D Printing Orbital Implant Templates in Secondary Orbital Reconstructions

PURPOSE

Despite its increasing use in craniofacial reconstructions, three-dimensional (3D) printing of customized orbital implants has not been widely adopted. Limitations include the cost of 3D printers able to print in a biocompatible material suitable for implantation in the orbit and the breadth of available implant materials. The authors report the technique of low-cost 3D printing of orbital implant templates used in complex, often secondary, orbital reconstructions.

METHODS

A retrospective case series of 5 orbital reconstructions utilizing a technique of 3D printed orbital implant templates is presented. Each patient's Digital Imaging and Communications in Medicine data were uploaded and processed to create 3D renderings upon which a customized implant was designed and sent electronically to printers open for student use at our affiliated institutions. The mock implants were sterilized and used intraoperatively as a stencil and mold. The final implant material was chosen by the surgeons based on the requirements of the case.

RESULTS

Five orbital reconstructions were performed with this technique: 3 tumor reconstructions and 2 orbital fractures. Four of the 5 cases were secondary reconstructions. Molded Medpor Titan (Stryker, Kalamazoo, MI) implants were used in 4 cases and titanium mesh in 1 case. The stenciled and molded implants were adjusted no more than 2 times before anchored in place (mean 1). No case underwent further revision.

CONCLUSIONS

The technique and cases presented demonstrate 1) the feasibility and accessibility of low-cost, independent use of 3D printing technology to fashion patient-specific implants in orbital reconstructions, 2) the ability to apply this technology to the surgeon's preference of any routinely implantable material, and 3) the utility of this technique in complex, secondary reconstructions.

Application of 3D printing for treating fractures of both columns of the acetabulum: Benefit of pre-contouring plates on the mirrored healthy pelvis

Acetabular fractures can be challenging to treat, in part because the shape of the fixation plates needs to be adjusted during the surgical procedure. One possibility is to generate a model of the uninjured half of a fractured pelvis with 3D printing, and then pre-contour the fixation plates preoperatively on this model. The purpose of this technical note is to describe how we used 3D printing as an aid to treat acetabular fractures. The quality of the fracture reduction, fracture fixation and time savings were evaluated. Three-dimensional reconstructions of the preoperative CT scan of the pelvis were exported with OsiriX™ software, mirrored with Meshmixer™ software and then printed in polylactic acid (PLA). Two fracture fixation plates were pre-contoured on the printed hemipelvis and then sterilized. No additional intraoperative contouring was needed. Anatomical reduction was obtained with an estimated 30-minute time saving and € 6 consumables cost.

Guidelines for patient-specific jawline definition with titanium implants in esthetic, deformity, and malformation surgery

Context:

Asymmetry and unfavorable esthetics of the jawline have become possible to correct in three dimensions using computer aided design and computer aided manufacturing.

Aims:

The aim of this study was to provide esthetic, technical, and operative guidelines for mandibular angle and border augmentation using patient-specific titanium implants made by selective laser melting.

Settings and Design:

University hospital - prospective registry.

Subjects and Methods:

Twelve patients and 17 implantation sites were documented and prospectively registered. Malformational, deformational, and purely esthetic indications were encountered.

Statistical Analysis Used:

Descriptive.

Results:

Patient satisfaction was high, probably because the patients had input into the planned dimensions and shape. A serious infection with implant removal occurred in one patient who had six previous surgeries at the same sites. Technical and surgical guidelines were developed including splitting implants into two segments when the mental nerve was at risk, using a three-dimensional (3D) puzzle connection, providing at least two screw holes per segment, using scaffolds at the bony contact side, using a “satin” finish at the periosteal side, referring to anatomical structures where possible, making provisions for transbuccal and transoral fixation, using a high vestibular incision, and using a double-layer closure. Esthetic guidelines are discussed but could not be upgraded.

Conclusions:

Mirroring techniques and 3D print accuracy up to 0.1 mm allow precise planning of jaw angle implants. Patients are pleased when given preoperative renderings for their consideration. Infections can be managed using technical and operative recommendations and careful patient selection.