3D printing in medicine最新文献

Background: The rapid expansion and anticipated U.S Food and Drug Administration regulation of 3D printing at the point-of-care necessitates the creation of robust quality management systems. A critical component of any quality management system is a document control system for the organization, tracking, signature collection, and distribution of manufacturing documentation. While off-the-shelf solutions for document control exist, external programs are costly and come with network security concerns. Here, we present our internally developed, cost-effective solution for an electronic document control system for 3D printing at the point-of-care.

Methods: We created a hybrid document control system by linking two commercially available platforms, Microsoft SharePoint and Adobe Sign, using a customized document approval workflow.

Results: Our platform meets all Code of Federal Regulations Title 21, Part 11 guidances.

Conclusion: Our hybrid solution for document control provides an affordable system for users to sort, manage, store, edit, and sign documents. The system can serve as a framework for other 3D printing programs to prepare for future U.S Food and Drug Administration regulation, improve the efficiency of 3D printing at the point-of-care, and enhance the quality of work produced by their respective program.

Background: Complex facial wounds can be difficult to stabilize due to proximity of vital structures. We present a case in which a patient-specific wound splint was manufactured using computer assisted design and three-dimensional printing at the point-of-care to allow for wound stabilization in the setting of hemifacial necrotizing fasciitis. We also describe the process and implementation of the United States Food and Drug Administration Expanded Access for Medical Devices Emergency Use mechanism.

Case presentation: A 58-year-old female presented with necrotizing fasciitis of the neck and hemiface. After multiple debridements, she remained critically ill with poor vascularity of tissue in the wound bed and no evidence of healthy granulation tissue and concern for additional breakdown towards the right orbit, mediastinum, and pretracheal soft tissues, precluding tracheostomy placement despite prolonged intubation. A negative pressure wound vacuum was considered for improved healing, but proximity to the eye raised concern for vision loss due to traction injury. As a solution, under the Food and Drug Administration's Expanded Access for Medical Devices Emergency Use mechanism, we designed a three-dimensional printed, patient-specific silicone wound splint from a CT scan, allowing the wound vacuum to be secured to the splint rather than the eyelid. After 5 days of splint-assisted vacuum therapy, the wound bed stabilized with no residual purulence and developed healthy granulation tissue, without injury to the eye or lower lid. With continued vacuum therapy, the wound contracted to allow for safe tracheostomy placement, ventilator liberation, oral intake, and hemifacial reconstruction with a myofascial pectoralis muscle flap and a paramedian forehead flap 1 month later. She was eventually decannulated and at six-month follow-up has excellent wound healing and periorbital function.

Conclusions: Patient-specific, three-dimensional printing is an innovative solution that can facilitate safe placement of negative pressure wound therapy adjacent to delicate structures. This report also demonstrates feasibility of point-of-care manufacturing of customized devices for optimizing complex wound management in the head and neck, and describes successful use of the United States Food and Drug Administration's Expanded Access for Medical Devices Emergency Use mechanism.

Background: Custom orthoses are becoming more commonly prescribed for upper and lower limbs. They require some form of shape-capture of the body parts they will be in contact with, which generates an STL file that designers prepare for manufacturing. For larger devices such as custom-contoured wheelchair cushions, the STL created during shape-capture can contain hundreds of thousands of tessellations, making them difficult to alter and prepare for manufacturing using mesh-editing software. This study covers the development and testing of a mesh-to-surface workflow in a parametric computer-aided design software using its visual programming language such that STL files of custom wheelchair cushions can be efficiently converted into a parametric single surface.

Methods: A volunteer in the clinical space with expertise in computer-aided design aided was interviewed to understand and document the current workflow for creating a single surface from an STL file of a custom wheelchair cushion. To understand the user needs of typical clinical workers with little computer-aided design experience, potential end-users of the process were tasked with completing the workflow and providing feedback during the experience. This feedback was used to automate part of the computer-aided design process using a visual programming tool, creating a new semi-automated workflow for mesh-to-surface translation. Both the original and semi-automated process were then evaluated by nine volunteers with varying levels of computer-aided design experience.

Results: The semi-automated process showed a 37% reduction in the total number of steps required to convert an STL model to a parametric surface. Regardless of previous computer-aided design experience, volunteers completed the semi-automated workflow 31% faster on average than the manual workflow.

Conclusions: The creation of a semi-automated process for creating a single parametric surface of a custom wheelchair cushion from an STL mesh makes mesh-to-surface conversion more efficient and more user-friendly to all, regardless of computer-aided design experience levels. The steps followed in this study may guide others in the development of their own mesh-to-surface tools in the wheelchair sector, as well as those creating other large custom prosthetic devices.

Background: Medical trainees frequently note that cardiac anatomy is difficult to conceive within a two dimensional framework. The specific anatomic defects and the subsequent pathophysiology in flow dynamics may become more apparent when framed in three dimensional models. Given the evidence of improved comprehension using such modeling, this study aimed to contribute further to that understanding by comparing Virtual Reality (VR) and 3D printed models (3DP) in medical education.

Objectives: We sought to systematically compare the perceived subjective effectiveness of Virtual Reality (VR) and 3D printed models (3DP) in the educational experience of residents and nurse practitioners.

Methods: Trainees and practitioners underwent individual 15-minute teaching sessions in which features of a developmentally typical heart as well as a congenitally diseased heart were demonstrated using both Virtual Reality (VR) and 3D printed models (3DP). Participants then briefly explored each modality before filling out a short survey in which they identified which model (3DP or VR) they felt was more effective in enhancing their understanding of cardiac anatomy and associated pathophysiology. The survey included a binary summative assessment and a series of Likert scale questions addressing usefulness of each model type and degree of comfort with each modality.

Results: Twenty-seven pediatric residents and 3 nurse practitioners explored models of a developmentally typical heart and tetralogy of Fallot pathology. Most participants had minimal prior exposure to VR (1.1 ± 0.4) or 3D printed models (2.1 ± 1.5). Participants endorsed a greater degree of understanding with VR models (8.5 ± 1) compared with 3D Printed models (6.3 ± 1.8) or traditional models of instruction (5.5 ± 1.5) p < 0.001. Most participants felt comfortable with modern technology (7.6 ± 2.1). 87% of participants preferred VR over 3DP.

Conclusions: Our study shows that, overall, VR was preferred over 3DP models by pediatric residents and nurse practitioners for understanding cardiac anatomy and pathophysiology.

Medical 3D printing is a form of manufacturing that benefits patient care, particularly when the 3D printed part is patient-specific and either enables or facilitates an intervention for a specific condition. Most of the patient-specific medical 3D printing begins with volume based medical images of the patient. Several digital manipulations are typically performed to prescribe a final anatomic representation that is then 3D printed. Among these are image segmentation where a volume of interest such as an organ or a set of tissues is digitally extracted from the volumetric imaging data. Image segmentation requires medical expertise, training, software, and effort. The theme of image segmentation has a broad intersection with medical 3D printing. The purpose of this editorial is to highlight different points of that intersection in a recent thematic series within 3D Printing in Medicine.

Background: Bone is a highly complex composite material which makes it hard to find appropriate artificial surrogates for patient-specific biomechanical testing. Despite various options of commercially available bones with generic geometries, these are either biomechanically not very realistic or rather expensive.

Methods: In this work, additive manufacturing was used for the fabrication of artificial femoral bones. These were based on CT images of four different commercially available femoral bone surrogates and three human bones with varying bone density. The models were 3D printed using a low-budget fused deposition modeling (FDM) 3D printer and PLA filament. The infill density was mechanically calibrated and varying cortical thickness was used. Compression tests of proximal femora simulating stance were performed and the biomechanical behavior concerning ultimate force, spring stiffness, and fracture pattern were evaluated as well as compared to the results of commercial and cadaveric bones.

Results: Regarding the ultimate forces and spring stiffness, the 3D printed analogs showed mechanical behavior closer to their real counterparts than the commercially available polyurethan-based surrogates. Furthermore, the increase in ultimate force with increasing bone density observed in human femoral bones could be reproduced well. Also, the fracture patterns observed match well with fracture patterns observed in human hip injuries.

Conclusion: Consequently, the methods presented here show to be a promising alternative for artificial generic surrogates concerning femoral strength testing. The manufacturing is straightforward, cheap, and patient-specific geometries are possible.

Background: Like most hospitals, our hospital experienced COVID-19 pandemic-related supply chain shortages. Our additive manufacturing lab's capacity to offset these shortages was soon overwhelmed, leading to a need to improve the efficiency of our existing workflow. We undertook a work system analysis guided by the Systems Engineering Initiative for Patient Safety (SEIPS) construct which is based on human factors and quality improvement principles. Our objective was to understand the inefficiencies in project submission, review, and acceptance decisions, and make systematic improvements to optimize lab operations.

Methods: Contextual inquiry (interviews and workflow analysis) revealed suboptimal characteristics of the system, specifically, reliance on a single person to facilitate work and, at times, fractured communication with project sponsors, with root causes related to the project intake and evaluation process as identified through SEIPS tools. As interventions, the analysis led us to: 1) enhance an existing but underused project submission form, 2) design and implement an internal project scorecard to standardize evaluation of requests, and 3) distribute the responsibility of submission evaluation across lab members. We implemented these interventions in May 2021 for new projects and compare them to our baseline February 1, 2018 through - April 30, 2021 performance (1184 days).

Results: All project requests were submitted using the enhanced project submission form and all received a standardized evaluation with the project scorecard. Prior to interventions, we completed 35/79 (44%) of projects, compared to 12/20 (60%) of projects after interventions were implemented. Time to review new submissions was reduced from an average of 58 days to 4 days. A more distributed team responsibility structure permitted improved workflow with no increase in staffing, allowing the Lab Manager to devote more time to engineering rather than administrative/decision tasks.

Conclusions: By optimizing our workflows utilizing a human factors approach, we improved the work system of our additive manufacturing lab to be responsive to the urgent needs of the pandemic. The current workflow provides insights for labs aiming to meet the growing demand for point-of-care manufacturing.

Background: 3D printed patient-specific titanium acetabular cups are used to treat patients with massive acetabular defects. These have highly porous surfaces, with the design intent of enhancing bony fixation. Our aim was to characterise these porous structures in commercially available designs.

Methods: We obtained 12 final-production, patient-specific 3D printed acetabular cups that had been produced by 6 manufacturers. High resolution micro-CT imaging was used to characterise morphometric features of their porous structures: (1) strut thickness, 2) the depth of the porous layer, (3) pore size and (4) the level of porosity. Additionally, we computed the surface area of each component to quantify how much titanium may be in contact with patient tissue. Statistical comparisons were made between the designs.

Results: We found a variability between designs in relation to the thickness of the struts (0.28 to 0.65 mm), how deep the porous layers are (0.57 to 11.51 mm), the pore size (0.74 to 1.87 mm) and the level of porosity (34 to 85%). One manufacturer printed structures with different porosities between the body and flange; another manufacturer had two differing porous regions within the body of the cups. The cups had a median (range) surface area of 756.5 mm² (348 - 1724).

Conclusions: There is a wide variability between manufacturers in the porous titanium structures they 3D print. We do not currently know whether there is an optimal porosity and how this variability will impact clinically on the integrity of bony fixation; this will become clearer as post market surveillance data is generated.

Background: Access to imaging reports and review of the breast imaging directly with a patient with breast cancer helps improve the understanding of disease extent and severity. A 3D printed breast model can further enhance a patient's understanding and communication with the healthcare team resulting in improved patient comprehension and patient input with reduced treatment decision conflict. Furthermore, 3D printed models can facilitate training of residents and fellows involved in the diagnosis and treatment management of breast cancer.

Case presentation: We present a 3D printed breast tumor model segmented from positron electron tomography/computed tomography and fabricated via desktop vat polymerization as proof of concept for treatment planning for a patient diagnosed with triple negative inflammatory breast carcinoma.

Conclusion: We illustrate benefits and indications for 3D printing in the management of breast cancer and specifically inflammatory breast cancer in this case. Fabrication and implementation of 3D printed models enhances patient's understanding and communication with the healthcare team regarding their condition, treatment options and anticipated outcomes. It provides personalized treatment planning by examining patient-specific pathology and the anatomic spatial relationships. Furthermore, 3D printed models facilitate medical education for trainees across disciplines involved in the patient's care.

Purpose: Current paper aims to describe a simple technique used for the fixation of the screws of a customized implant via a universal screw driver (BoneTrust® Easy Screw according to Dr. Bayer, Medical Instinct®, GmbH, Germany) to simplify the surgical placement of the customized implants.

Methods: The insertion of the drilling screws for the retention of the implant with angulated handpiece into the palatinal region or zygomatic buttress were performed with universal screw driver.

Results: The retention screws could be inserted with a proper angulation without interfering with the surrounding tissues. The technique described herein has significantly simplified the surgical intervention.

Conclusion: The insertion of the drilling screws for the retention of the implant with angulated handpiece into the palatinal region or zygomatic buttress could be challenging, thus the anatomical structures and the insufficient length of the handpiece could interfere with the placement of the screw with a proper angulation. This problem could be easily managed with the use of universal screw driver.