3D printing in medicine最新文献

The use of medical 3D printing has expanded dramatically for breast diseases. A writing group composed of the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing (SIG) provides updated appropriateness criteria for breast 3D printing in various clinical scenarios. Evidence-based appropriateness criteria are provided for the following clinical scenarios: benign breast lesions and high-risk breast lesions, breast cancer, breast reconstruction, and breast radiation (treatment planning and radiation delivery).

Objective: Developments in 3-dimensional (3D) printing technology has made it possible to produce high quality, affordable 3D printed models for use in medicine. As a result, there is a growing assessment of this approach being published in the medical literature. The objective of this study was to outline the clinical applications of individualized 3D printing in gynecology through a scoping review.

Data sources: Four medical databases (Medline, Embase, Cochrane CENTRAL, Scopus) and grey literature were searched for publications meeting eligibility criteria up to 31 May 2021.

Study eligibility criteria: Publications were included if they were published in English, had a gynecologic context, and involved production of patient specific 3D printed product(s).

Study appraisal and synthesis methods: Studies were manually screened and assessed for eligibility by two independent reviewers and data were extracted using pre-established criteria using Covidence software.

Results: Overall, 32 studies (15 abstracts,17 full text articles) were included in the scoping review. Most studies were either case reports (12/32,38%) or case series (15/32,47%). Gynecologic sub-specialties in which the 3D printed models were intended for use included: gynecologic oncology (21/32,66%), benign gynecology (6/32,19%), pediatrics (2/32,6%), urogynecology (2/32,6%) and reproductive endocrinology and infertility (1/32,3%). Twenty studies (63%) printed 5 or less models, 6/32 studies (19%) printed greater than 5 (up to 50 models). Types of 3D models printed included: anatomical models (11/32,34%), medical devices, (2/32,6%) and template/guide/cylindrical applicators for brachytherapy (19/32,59%).

Conclusions: Our scoping review has outlined novel clinical applications for individualized 3D printed models in gynecology. To date, they have mainly been used for production of patient specific 3D printed brachytherapy guides/applicators in patients with gynecologic cancer. However, individualized 3D printing shows great promise for utility in surgical planning, surgical education, and production of patient specific devices, across gynecologic subspecialties. Evidence supporting the clinical value of individualized 3D printing in gynecology is limited by studies with small sample size and non-standardized reporting, which should be the focus of future studies.

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: Polymethyl methacrylate, or "bone cement," can be used intraoperatively to replace damaged or diseased bone and to deliver local antibiotics. 3D printed molds allow surgeons to form personalized and custom shapes with bone cement. One factor hindering the clinical utility of anatomically accurate 3D printed molds is that cured bone cement can be difficult to remove due to the strong adhesion between the mold and the bone cement. One way to reduce the adhesion between the 3D printed mold and the cured bone cement is with the use of a surface coating, such as a lubricant. This study sought to determine the optimal surface coating to prevent bone cement adhesion to 3D printed molds that could be utilized within a sterile operating room environment.

Methods: Hemispheric molds were 3D printed using a stereolithography printer. The molds were coated with four sterile surface coatings available in most operating theatres (light mineral oil, bacitracin ointment, lubricating jelly, and ultrasound transmission gel). Polymethyl methacrylate with tobramycin antibiotic was mixed and poured into the molds. The amount of force needed to "push out" the cured bone cement from the molds was measured to determine the efficacy of each surface coating. Tukey's multiple comparison test was performed to compare the results of the pushout test.

Results: The average pushout force for the surface coatings, in increasing order, were as follows (mean ± standard deviation) --- bacitracin ointment: 9.10 ± 6.68 N, mineral oil: 104.93 ± 69.92 N, lubricating jelly: 147.76 ± 63.77 N, control group: 339.31 ± 305.20 N, ultrasound transmission gel 474.11 ± 94.77 N. Only the bacitracin ointment required significantly less pushout force than the control (p = 0.0123).

Conclusions: The bacitracin ointment was the most effective surface coating, allowing the bone cement to be pushed out of the mold using the least amount of force. In addition, the low standard deviation speaks to the reliability of the bacitracin ointment to reduce mold adhesion compared to the other surface coatings. Given its efficacy as well as its ubiquitous presence in the hospital operating room setting, bacitracin ointment is an excellent choice to prevent adhesion between bone cement and 3D printed molds intraoperatively.

Background: The goal of stabilization of the femoral neck is to limit morbidity and mortality from fracture. Of three potential methods of fixation, (three percutaneous screws, the Synthes Femoral Neck System, and a dynamic hip screw), each requires guide wire positioning of the implant(s) in the femoral neck and head. Consistent and accurate positioning of these systems is paramount to reduce surgical times, stabilize fractures effectively, and reduce complications. To help expedite surgery and achieve ideal implant positioning in the geriatric population, we have developed and validated a surgical planning methodology using 3D modelling and printing technology.

Methods: Using image processing software, 3D surgical models were generated placing guide wires in a virtual model of an osteoporotic proximal femur sawbone. Three unique drill guides were created to achieve the optimal position for implant placement for each of the three different implant systems, and the guides were 3D printed. Subsequently, a trauma fellowship trained orthopedic surgeon used the 3D printed guides to position 2.8 mm diameter drill bit tipped guide wires into five osteoporotic sawbones for each of the three systems (fifteen sawbones total). Computed Tomography (CT) scans were then taken of each of the sawbones with the implants in place. 3D model renderings of the CT scans were created using image processing techniques and the displacement and angular deviations at guide wire entry to the optimal sawbone model were measured.

Results: Across all three percutaneous screw guide wires, the average displacement was 3.19 ± 0.12 mm and the average angular deviation was 4.10 ± 0.17^o. The Femoral Neck System guide wires had an average displacement of 1.59 ± 0.18 mm and average angular deviation of 2.81 ± 0.64^o. The Dynamic Hip Screw had an average displacement of 1.03 ± 0.19 mm and average angular deviation of 2.59 ± 0.39^o.

Conclusion: The use of custom 3D printed drill guides to assist with the positioning of guide wires proved to be accurate for each of the three types of surgical strategies. Guides which are used to place more than 1 guide wire may have lower positional accuracy, as the guide may shift during multiple wire insertions. We believe that personalized point of care drill guides provide an accurate intraoperative method for positioning implants into the femoral neck.