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Designing and manufacturing medical devices for specific patients is becoming increasingly feasible with developments in 3D printing and 3D imaging software. This raises the question of how patient-specific devices can be evaluated, since our ‘gold standard’ method for evaluation, the randomised controlled trial (RCT), requires that an intervention is standardised across a number of individuals in an experimental group. I distinguish several senses of patient-specific device, and focus the discussion on understanding the problem of variations between instances of an intervention for RCT evaluation. I argue that, despite initial appearances, it is theoretically possible to use RCTs to evaluate some patient-specific medical devices. However, the argument reveals significant difficulties for ensuring the validity of such trials, with implications for how we should think about methods of evidence gathering and regulatory approaches for these technologies.

Additive manufacturing with fused deposition modeling (FDM) is currently optimized for a wide range of research and commercial applications. The major disadvantage of FDM-created products is their low quality and structural defects (porosity), which impose an obstacle to utilizing them in functional prototyping and direct digital manufacturing of objects intended to contact with gases and liquids. This article describes a simple and efficient approach for assessing the quality of 3D printed objects. Using this approach it was shown that the wall permeability of a printed object depends on its geometric shape and is gradually reduced in a following series: cylinder > cube > pyramid > sphere > cone. Filament feed rate, wall geometry and G-code-defined wall structure were found as primary parameters that influence the quality of 3D-printed products. Optimization of these parameters led to an overall increase in quality and improvement of sealing properties. It was demonstrated that high quality of 3D printed objects can be achieved using routinely available printers and standard filaments.

In the present study, chitosan (CS) and pectin (PEC) were utilized for the preparation of 3D printable inks through pneumatic extrusion for biomedical applications. CS is a polysaccharide with beneficial properties; however, its printing behavior is not satisfying, rendering the addition of a thickening agent necessary, i.e., PEC. The influence of PEC in the prepared inks was assessed through rheological measurements, altering the viscosity of the inks to be suitable for 3D printing. 3D printing conditions were optimized and the effect of different drying procedures, along with the presence or absence of a gelating agent on the CS-PEC printed scaffolds were assessed. The mean pore size along with the average filament diameter were measured through SEM micrographs. Interactions among the characteristic groups of the two polymers were evident through FTIR spectra. Swelling and hydrolysis measurements confirmed the influence of gelation and drying procedure on the subsequent behavior of the scaffolds. Ascribed to the beneficial pore size and swelling behavior, fibroblasts were able to survive upon exposure to the ungelated scaffolds.

Three‐dimensional (3D) printing has shown great promise in medicine with increasing reports in congenital heart disease (CHD). This systematic review aims to analyse the main clinical applications and accuracy of 3D printing in CHD, as well as to provide an overview of the software tools, time and costs associated with the generation of 3D printed heart models. A search of different databases was conducted to identify studies investigating the application of 3D printing in CHD. Studies based on patient's medical imaging datasets were included for analysis, while reports on in vitro phantom or review articles were excluded from the analysis. A total of 28 studies met selection criteria for inclusion in the review. More than half of the studies were based on isolated case reports with inclusion of 1–12 cases (61%), while 10 studies (36%) focused on the survey of opinion on the usefulness of 3D printing by healthcare professionals, patients, parents of patients and medical students, and the remaining one involved a multicentre study about the clinical value of 3D printed models in surgical planning of CHD. The analysis shows that patient‐specific 3D printed models accurately replicate complex cardiac anatomy, improve understanding and knowledge about congenital heart diseases and demonstrate value in preoperative planning and simulation of cardiac or interventional procedures, assist surgical decision‐making and intra‐operative orientation, and improve patient‐doctor communication and medical education. The cost of 3D printing ranges from USD 55 to USD 810. This systematic review shows the usefulness of 3D printed models in congenital heart disease with applications ranging from accurate replication of complex cardiac anatomy and pathology to medical education, preoperative planning and simulation. The additional cost and time required to manufacture the 3D printed models represent the limitations which need to be addressed in future studies. This systematic review analyses 28 studies published about the applications of 3D printing in congenital heart disease and results show the usefulness of 3D printed models in congenital heart disease with applications ranging from accurate replication of complex cardiac anatomy and pathology to medical education, preoperative planning and simulation.

Bioink optimization is considered as one of main challenges in cell-laden 3D bioprinting. Alginate-Gelatin (Alg-Gel) hydrogel have been extensively used as bioink. However, its properties could be influenced by various parameters, and little is known about the evidence featuring the impact of solvent. Here we investigated four Alg-Gel bioink by varying solvent ionic strength (named B-1, B-2, B-3 and B-4). Mechanical properties and printability of bioink samples and their impacts on behaviors of encapsulated epidermal stem cells (ESCs) were tested. Bioink with increased ionic strength of solvent showed decreased stiffness and viscosity, and increased swelling and degradation by printability and mechanical property tests. Due to the increased swelling and degradation was associated with shape-maintenance of post-printing constructs, B-3 and B-4 were hardly observable after 14 days. Cellular behaviors were assessed through viability, proliferation, aggregation and differentiation tests. B-2 with optimal properties resulted in higher viability and proliferation of ESCs, and further facilitated cellular aggregation and lineage differentiation. We demonstrated that the solvent can be tuned by ionic strength to control the properties of Alg-Gel bioink and post-printing constructs, which represented a promising avenue for promotion of therapeutic stem cell behaviors in 3D bioprinting.

Three-dimensional (3D) printing has attracted a huge interest in recent years. Broadly speaking, it refers to the technology which converts a predesigned virtual model to a touchable object. In clinical medicine, it usually converts a series of two-dimensional medical images acquired through computed tomography, magnetic resonance imaging or 3D echocardiography into a physical model. Medical 3D printing consists of three main steps: image acquisition, virtual reconstruction and 3D manufacturing. It is a promising tool for preoperative evaluation, medical device design, hemodynamic simulation and medical education, it is also likely to reduce operative risk and increase operative success. However, the most relevant studies are case reports or series which are underpowered in testing its actual effect on patient outcomes. The decision of making a 3D cardiac model may seem arbitrary since it is mostly based on a cardiologist's perceived difficulty in performing an interventional procedure. A uniform consensus is urgently necessary to standardize the key steps of 3D printing from imaging acquisition to final production. In the future, more clinical trials of rigorous design are possible to further validate the effect of 3D printing on the treatment of cardiovascular diseases. (Cardiol J 2017; 24, 4: 436-444).

Background Titanium cage subsidence remains a common complication following anterior cervical corpectomy and fusion. 3D printing technology can optimize titanium cages, including high geometric matching and unique porous graded structures, providing a better option for improving titanium cage subsidence. This study aims to evaluate the mechanical properties of 3D-printed titanium cages and compare them with those of conventional titanium cages, providing preclinical data for future clinical trials. Methods The samples were divided into a 3D-printed titanium cage group and a conventional titanium cage group, with 5 samples in each group. A static compression test was conducted using the American Society for Testing and Materials (ASTM) F2077-14 standard to evaluate the stiffness of the titanium cages. A static subsidence test was conducted using the ASTM F2267-04 standard to evaluate the stiffness (K p ) of the test blocks in different groups of Sawbone. The larger the K p value, the smaller the tendency of titanium cage subsidence. Results In the static compression test, the stiffness of the 3D-printed titanium cage and the conventional titanium cage were (6562.60 ± 390.72) N/mm and (10252.40 ± 704.07) N/mm, respectively, with a statistically significant difference ( P  < 0.05). In the static subsidence test, the stiffness of the 3D-printed titanium cage system and the conventional titanium cage system were (258.60 ± 7.99) N/mm and (221.00 ± 20.36) N/mm, respectively, with a statistically significant difference ( P  < 0.05). Additionally, the stiffness (K p value) of the test block for the 3D-printed titanium cage in the static subsidence test was 270 N/mm, while the K p value of the test block in the conventional titanium cage static subsidence test was 226 N/mm, indicating a 19.5% increase in anti-subsidence capability. Conclusion The optimized 3D-printed titanium cage, featuring anatomical conformity and a 70% porous structure, demonstrates 19.5% improved anti-subsidence performance compared to conventional designs, addressing limitations in prior 3D-printed solutions, providing a promising and feasible solution for reducing the subsidence of titanium cages.

BACKGROUND AND OBJECTIVESAdvanced haptic simulators for neuraxial training are expensive, have a finite life, and are not patient specific. We sought to demonstrate the feasibility of developing a custom-made, low-cost, 3-dimensionally printed thoracic spine simulator model from patient computed tomographic scan data. This study assessed the modelʼs practicality, efficiency as a teaching tool, and the transfer of skill set into patient care. METHODSA high-fidelity, patient-specific thoracic spine model was used for the study. Thirteen residents underwent a 1-hour 30-minute training session prior to performing thoracic epidural analgesia (TEA) on patients. We observed another group of 14 residents who were exposed to the traditional method of training during their regional anesthesia rotation for thoracic epidural placement. The TEA was placed for patients under the supervision of attending anesthesiologists, who were blinded to the composition of the study and control groups. As a primary outcome, data were collected on successful TEAs, which was defined as a TEA that provided full relief of sensation across the entire surgical area as assessed by both a pinprick and temperature test. Secondary outcomes included whether any assistance from the attending physician was required and failed epidurals. RESULTSA total of 27 residents completed the study (14 in the traditional training, 13 in the study group). We found that the residents who underwent training with the simulator had a significantly higher success rate (11 vs 4 successful epidural attempts, P = 0.002) as compared with the traditional training group. The control group also required significantly more assistance from the supervising anesthesiologist compared with the study group (5 vs 1 attempt requiring guidance). The number needed to treat (NNT) for the traditional training group was 1.58 patients over the study period with a 95% confidence interval of 1.55 to 1.61. CONCLUSIONSBy using patient-specific, 3-dimensionally printed, thoracic spine models, we demonstrated a significant improvement in clinical proficiency as compared with traditional teaching models.

Introduction Three‐dimensional printing technology has the potential to streamline custom bolus production in radiotherapy. This study evaluates the volumetric, dosimetric and cost differences between traditional wax and 3D printed versions of nose bolus. Method Nose plaster impressions from 24 volunteers were CT scanned and planned. Planned virtual bolus was manufactured in wax and created in 3D print (100% and 18% shell infill density) for comparison. To compare volume variations and dosimetry, each constructed bolus was CT scanned and a plan replicating the reference plan fields generated. Bolus manufacture time and material costs were analysed. Results Mean volume differences between the virtual bolus (VB) and wax, and the VB and 18% and 100% 3D shells were −3.05 ± 11.06 cm3, −1.03 ± 8.09 cm3 and 1.31 ± 2.63 cm3, respectively. While there was no significant difference for the point and mean doses between the 100% 3D shell filled with water and the VB plans (P> 0.05), the intraclass coefficients for these dose metrics for the 100% 3D shell filled with wax compared to VB doses (0.69–0.96) were higher than those for the 18% and 100% 3D shell filled with water and the wax (0.48–0.88). Average costs for staff time and materials were higher for the wax ( $138.54 and $ 20.49, respectively) compared with the 3D shell prints ( $10.58 and $ 13.87, respectively). Conclusion Three‐dimensional printed bolus replicated the VB geometry with less cost for manufacture than wax bolus. When shells are printed with 100% infill density, 3D bolus dosimetrically replicates the reference plan. This study evaluated the volumetric, dosimetric and cost differences between wax and 3D printed versions of customised bolus used in the radiotherapy treatment of the nose. Three‐dimensional printed bolus replicated the virtual bolus geometry with less cost for manufacture than wax bolus. When printed with 100% internal wall fill, 3D bolus dosimetrically replicates the reference plan.

Background and ObjectivesThoracic epidural anesthesia is a technically challenging procedure with a high failure rate of 24% to 32% nationwide. Residents in anesthesiology have limited opportunities to practice this technique adequately, and there are no training tools available for this purpose. Our objective was to build a low-cost patient-specific thoracic epidural training model.MethodsWe obtained thoracic computed tomography scan data from patients with normal and kyphotic spine. The thoracic spine was segmented from the scan, and a 3-dimensional model of the spine was generated and printed. It was then placed in a customized wooden box and filled with different types of silicone to mimic human tissues. Attending physicians in our institution then tested the final model. They were asked to fill out a brief questionnaire after the identification of the landmarks and epidural space using ultrasound and real-time performance for a thoracic epidural on the model (Supplemental Digital Content 1, http://links.lww.com/AAP/A197). Likert scoring system was used for scoring.ResultsThe time to develop this simulator model took less than 4 days, and the materials cost approximately $400. Fourteen physicians tested the model for determining the realistic sensation while palpating the spinous process, needle entry through the silicone, the “pop” sensation and ultrasound fidelity of the model. Whereas the tactile fidelity scores were “neutral” (3.08, 3.06, and 3.0, respectively), the ultrasound guidance and overall suitability for residents were highly rated as being the most realistic (4.85 and 4.0, respectively).ConclusionsIt is possible to develop homemade, low-cost, patient-specific, and high-fidelity ultrasound guidance simulators for resident training in thoracic epidurals using 3-dimensional printing technology.