Safety and usability of proning pillows in intensive care: A scoping review.

OBJECTIVES: Proning is an established technique for the care of intubated patients with severe respiratory failure. Positioning devices used to support the head and body of patients placed in the prone position are often associated with the formation of pressure injuries. Despite robust literature on the prevention and monitoring of pressure injuries, little is described about the role of proning pillows on pressure injuries. The objective of this review is to understand the extent of evidence pertaining to the safety and usability of different types of proning pillows in the intensive care setting. REVIEW METHOD: A scoping review of the literature was completed using predefined search terms in three databases and identified 296 articles. An additional 26 were included from reference lists. Twenty studies are included in the analysis; most were published in the past 3 years, with >50% in surgical settings. DATA SOURCES: Three databases were searched: PubMed, Scopus, and EMBASE. REVIEW METHODS: The review followed the PRISMA Extension for Scoping Reviews, and data were reviewed using Covidence. RESULTS: The most prevalent proning pillow is a standard, noncontoured foam head positioner. It is responsible for the majority of facial pressure injuries in all settings of care. Memory foam pillows and helmet-based systems offer improved surface pressure distribution, although their usability in the intensive care setting remains poorly studied. Inflatable air-cell-based devices present an alternative, but the lack of supporting research and the costs may explain their poor uptake. Several articles proposed the use of pressure sensor systems to evaluate devices. We propose a set of ergonomic parametres to consider when choosing or designing a positioning device for proned patients. CONCLUSION: The evidence pertaining to the safety and usability of proning pillows in the intensive care setting is scarce, which provides opportunities for future research to improve the efficacy in the prevention of pressure injuries and the user experience.

Personalized Volumetric Tissue Generation by Enhancing Multiscale Mass Transport through 3D Printed Scaffolds in Perfused Bioreactors.

Engineered tissues provide an alternative to graft material, circumventing the use of donor tissue such as autografts or allografts and non-physiological synthetic implants. However, their lack of vasculature limits the growth of volumetric tissue more than several millimeters thick which limits their success post-implantation. Perfused bioreactors enhance nutrient mass transport inside lab-grown tissue but remain poorly customizable to support the culture of personalized implants. Here, a multiscale framework of computational fluid dynamics (CFD), additive manufacturing, and a perfusion bioreactor system are presented to engineer personalized volumetric tissue in the laboratory. First, microscale 3D printed scaffold pore geometries are designed and 3D printed to characterize media perfusion through CFD and experimental fluid testing rigs. Then, perfusion bioreactors are custom-designed to combine 3D printed scaffolds with flow-focusing inserts in patient-specific shapes as simulated using macroscale CFD. Finally, these computationally optimized bioreactor-scaffold assemblies are additively manufactured and cultured with pre-osteoblast cells for 7, 20, and 24 days to achieve tissue growth in the shape of human calcaneus bones of 13 mL volume and 1 cm thickness. This framework enables an intelligent model-based design of 3D printed scaffolds and perfusion bioreactors which enhances nutrient transport for long-term volumetric tissue growth in personalized implant shapes. The novel methods described here are readily applicable for use with different cell types, biomaterials, and scaffold microstructures to research therapeutic solutions for a wide range of tissues.

Properties and Characteristics of Three-Dimensional Printed Head Models Used in Simulation of Neurosurgical Procedures: A Scoping Review.

BACKGROUND: Intracranial surgery can be complex and high risk. Safety, ethical and financial factors make training in the area challenging. Head model 3-dimensional (3D) printing is a realistic training alternative to patient and traditional means of cadaver and animal model simulation. OBJECTIVE: To describe important factors relating to the 3D printing of human head models and how such models perform as simulators. METHODS: Searches were performed in PubMed, the Cochrane Library, Scopus, and Web of Science. Articles were screened independently by 3 reviewers using Covidence software. Data items were collected under 5 categories: study information; printers and processes; head model specifics; simulation and evaluations; and costs and production times. RESULTS: Forty articles published over the last 10 years were included in the review. A range of printers, printing methods, and substrates were used to create head models and tissue types. Complexity of the models ranged from sections of single tissue type (e.g., bone) to high-fidelity integration of multiple tissue types. Some models incorporated disease (e.g., tumors and aneurysms) and artificial physiology (e.g., pulsatile circulation). Aneurysm clipping, bone drilling, craniotomy, endonasal surgery, and tumor resection were the most commonly practiced procedures. Evaluations completed by those using the models were generally favorable. CONCLUSIONS: The findings of this review indicate that those who practice surgery and surgical techniques on 3D-printed head models deem them to be valuable assets in cranial surgery training. Understanding how surgical simulation on such models affects surgical performance and patient outcomes, and considering cost-effectiveness, are important future research endeavors.

3D Printing Improved Testicular Prostheses: Using Lattice Infill Structure to Modify Mechanical Properties.

Patients often opt for implantation of testicular prostheses following orchidectomy for cancer or torsion. Recipients of testicular prostheses report issues regarding firmness, shape, size, and position, aspects of which relate to current limitations of silicone materials used and manufacturing methods for soft prostheses. We aim to create a 3D printable testicular prosthesis which mimics the natural shape and stiffness of a human testicle using a lattice infill structure. Porous testicular prostheses were engineered with relative densities from 0.1 to 0.9 using a repeating cubic unit cell lattice inside an anatomically accurate testicle 3D model. These models were printed using a multi-jetting process with an elastomeric material and compared with current market prostheses using shore hardness tests. Additionally, standard sized porous specimens were printed for compression testing to verify and match the stiffness to human testicle elastic modulus (E-modulus) values from literature. The resulting 3D printed testicular prosthesis of relative density between 0.3 and 0.4 successfully achieved a reduction of its bulk compressive E-modulus from 360 KPa to a human testicle at 28 Kpa. Additionally, this is the first study to quantitatively show that current commercial testicular prostheses are too firm compared to native tissue. 3D printing allows us to create metamaterials that match the properties of human tissue to create customisable patient specific prostheses. This method expands the use cases for existing biomaterials by tuning their properties and could be applied to other implants mimicking native tissues.

Interobserver and intraobserver agreement of three-dimensionally printed models for the classification of proximal humeral fractures.

HYPOTHESIS: This study aimed to examine whether three-dimensionally printed models (3D models) could improve interobserver and intraobserver agreement when classifying proximal humeral fractures (PHFs) using the Neer system. We hypothesized that 3D models would improve interobserver and intraobserver agreement compared with x-ray, two-dimensional (2D) and three-dimensional (3D) computed tomography (CT) and that agreement using 3D models would be higher for registrars than for consultants. METHODS: Thirty consecutive PHF images were selected from a state-wide database and classified by fourteen observers. Each imaging modality (x-ray, 2D CT, 3D CT, 3D models) was grouped and presented in a randomly allocated sequence on two separate occasions. Interobserver and intraobserver agreements were quantified with kappa values (κ), percentage agreement, and 95% confidence intervals (CIs). RESULTS: Seven orthopedic registrars and seven orthopedic consultants classified 30 fractures on one occasion (interobserver). Four registrars and three consultants additionally completed classification on a second occasion (intraobserver). Interobserver agreement was greater with 3D models than with x-ray (κ = 0.47, CI: 0.44-0.50, 66.5%, CI: 64.6-68.4% and κ = 0.29, CI: 0.26-0.31, 57.2%, CI: 55.1-59.3%, respectively), 2D CT (κ = 0.30, CI: 0.27-0.33, 57.8%, CI: 55.5-60.2%), and 3D CT (κ = 0.35, CI: 0.33-0.38, 58.8%, CI: 56.7-60.9%). Intraobserver agreement appeared higher for 3D models than for other modalities; however, results were not significant. There were no differences in interobserver or intraobserver agreement between registrars and consultants. CONCLUSION: Three-dimensionally printed models improved interobserver agreement in the classification of PHFs using the Neer system. This has potential implications for using 3D models for surgical planning and teaching.

Spectral changes associated with transmission of OLED emission through human skin.

A recent and emerging application of organic light emitting diodes (OLEDs) is in wearable technologies as they are flexible, stretchable and have uniform illumination over a large area. In such applications, transmission of OLED emission through skin is an important part and therefore, understanding spectral changes associated with transmission of OLED emission through human skin is crucial. Here, we report results on transmission of OLED emission through human skin samples for yellow and red emitting OLEDs. We found that the intensity of transmitted light varies depending on the site from where the skin samples are taken. Additionally, we show that the amount of transmitted light reduces by ~ 35-40% when edge emissions from the OLEDs are blocked by a mask exposing only the light emitting area of the OLED. Further, the emission/electroluminescence spectra of the OLEDs widen significantly upon passing through skin and the full width at half maximum increases by >20 nm and >15 nm for yellow and red OLEDs, respectively. For comparison, emission profile and intensities of transmitted light for yellow and red inorganic LEDs are also presented. Our results are highly relevant for the rapidly expanding area of non-invasive wearable technologies that use organic optoelectronic devices for sensing.

Challenges in engineering large customized bone constructs.

The ability to treat large tissue defects with customized, patient-specific scaffolds is one of the most exciting applications in the tissue engineering field. While an increasing number of modestly sized tissue engineering solutions are making the transition to clinical use, successfully scaling up to large scaffolds with customized geometry is proving to be a considerable challenge. Managing often conflicting requirements of cell placement, structural integrity, and a hydrodynamic environment supportive of cell culture throughout the entire thickness of the scaffold has driven the continued development of many techniques used in the production, culturing, and characterization of these scaffolds. This review explores a range of technologies and methods relevant to the design and manufacture of large, anatomically accurate tissue-engineered scaffolds with a focus on the interaction of manufactured scaffolds with the dynamic tissue culture fluid environment. Biotechnol. Bioeng. 2017;114: 1129-1139. © 2016 Wiley Periodicals, Inc.