3D-printed Anatomical Models Research Articles

Pilot Study on Integrating 3D-Printed Models into Undergraduate Medical Education for Congenital Heart Disease

BackgroundThis study aimed to assess the feasibility and effectiveness of implementing 3D-printed heart models in the education of medical students in a Canadian Medical School. MethodsThree types of 3D-printed models – normal, unrepaired Tetralogy of Fallot (TOF) and surgically repaired adult TOF – were provided for medical students in their 2nd year of training after a 30-minute lecture. The repaired TOF model depicted a transannular patch, ventricular septal defect closure, and right ventricular outflow tract resection. Knowledge acquisition was measured by comparing pre-and post-session tests consisting of 5 questions. Learner satisfaction ratings were measured with questionnaires completed after the session. A statistical analysis was performed using the t-test. ResultsTwenty-two medical students participated in the study with 20 students submitting complete data for analysis. The students’ score on 5 questions improved after the 3D-printed model session. The average number of correct answers in the test was 2.1 ± 1.0 pre-session and 4.3 ± 0.9 post-session (P < 0.001) out of the possible total of 5. Participants reported a high level of satisfaction (86.4%), understanding (86.4%), and usefulness (90.9%) with the incorporation of 3D-printed models in the educational session. ConclusionsAn educational session which integrated 3D-printed anatomic models to teach congenital heart disease anatomy significantly enhanced knowledge outcomes. Learner assessment of the impact of the use of the 3D models was highly favourable.

Impact of 3D-Printed Anatomical Models on Doctor-Patient Communication in Orthopedic Consultations: A Randomized Clinical Trial.

Effective communication between doctors and patients is essential for treatment adherence and better clinical outcomes. Although 3D printing has advanced in medicine, its impact on doctor-patient communication still requires further investigation. This randomized clinical trial evaluated the effectiveness of 3D anatomical models as a tool to facilitate communication in orthopedic consultations. This randomized clinical trial was conducted between May 2024 and September 2024, with 46 patients randomized into two groups: 21 patients received medical explanations with the aid of 3D models, and 25 without. Patients' knowledge was assessed before and after the consultation, and the quality of communication was measured using the Communication Assessment Tool (CAT). In the group using 3D models, 76.19% of patients reported improved knowledge of their conditions, while in the group without models, the increase was 52.00%. Additionally, 14 out of 15 CAT parameters showed statistically significant differences between the groups, with p-values ranging from 0.001 to 0.021. The use of 3D models significantly improved patients' understanding and facilitated communication with doctors, proving to be an effective tool for explaining complex medical conditions.

Narrative review of latest research progress about robotic percutaneous coronary intervention.

Robotic percutaneous coronary intervention (R-PCI) is a novel technology in which operators can manipulate guidewires and catheter devices in interventional cardiology. This approach provides great benefits to interventional cardiologists in terms of reducing both radiation exposure and orthopedic injuries. Several large, high-quality cohort studies have confirmed the short-term safety and high technical success rate of R-PCI. However, randomized long-term data are still needed before adopting them as part of standard coronary interventions. Furthermore, tele-stenting for complex coronary lesions has significant potential for R-PCI. We need to overcome the present relevant challenges for its application such as inherent delays, bedside care for unstable patients from R-PCIs to manual PCIs (M-PCIs), incompatibility for a thrombus aspiration catheter and heavily calcified lesions. There is a great future in laboratory workflow teams, 3D-printed anatomical models and multiple joint collaborative control algorithms. This narrative review summarizes the latest developments in R-PCI, with a focus on developments in robotic technology, and discusses the current and future potential use of R-PCI in clinical practice globally.

Custom fabricated three-dimensional printed surgical guide for trephine bur in autogenous bone graft: A technique report.

This technique presents a workflow that designs the custom surgical guide to cover a trephine bur using simple slicer software and three-dimensional (3D) printing to perform the semilunar technique. This method in autogenous bone grafting surgery harvests a thin layer of cortical bone in the donor site with a trephine bur. Its biologically favorable, round shape can be used as a shell to reconstruct the ridge with a 3D contour acceptable for future implant placement. A 78-year-old female patient required vertical and horizontal bone grafting for future implant placement due to the infection caused by the vertically fractured root of a premolar. The patient's cone beam computed tomography (CBCT) file was translated into a standard tessellation language (STL) file, and recipient and donor site models were created. Simulated surgery was done using the software first to detect any possible complications during surgery. The trephine bur planned for use in surgery was measured in necessary dimensions, and the values were added to create a guide for surgery in slicer software. Then, it was 3D-printed with a stereolithography (SLA) printer. After testing the fit of the guide, it was further tested on a fused filament fabrication (FFF) printed donor site model to check if the desired shape and size of the plate were acquired after harvest. Then, the plates were used for model surgery on the recipient site model. After no issues from the previous steps, the final patient surgery was approved and completed with success. This technique utilizes the SLA printing method to create the custom surgical guide for a trephine bur without using commercially available products. Moreover, it could be tested on FFF 3D-printed anatomical models to ensure its validity. With this innovative technique, clinicians can efficiently perform a semilunar technique, facilitating the surgery and improving patient care.

3D printed anatomical models for preoperative planning of complex orthopaedic surgical operations of the lower limb

Complex multifragmentary fractures of the pelvis and lower limb are a major challenge for operative orthopaedic surgery. The successful metallic osteosynthesis of the fractures requires an extensive planning process, which can be dramatically improved with the 3D printed anatomical models – replicas of the bones with high fidelity generated from CT and MRI imaging studies. The models represent the spatial properties of the skeleton with a dimensional error of approximately 8 μm/mm. They can be manufactured easily and with high reproducibility with commercial or open-access software and FDM 3D printing. Orthopaedic surgeons use the preoperative models as a highly accurate physical model of complex fractures and allow them to choose and prepare the optimal operation window, surgical tools, metallic implants, and as a template for recontouring (pre-bending) of fixation plates, which will be used during the surgery. The approach provides a new level of personalisation in operative orthopaedic surgery and significantly reduces the duration of the operation, the amount of blood loss and the intraoperative X-rays. The proper anatomical repositioning of the fracture is achieved at a higher rate in the surgeries, which are planned with 3D-printed anatomical models. The planning of surgical operations with 3D-printed models increases the overall effectiveness of the surgery, reduces the rate of post-surgical complications, and allows for a patient-specific approach.The paper will describe the methods for manufacturing accurate 3D-printed anatomical models representing complex fractures and their application for preoperative planning of orthopaedic operation.The anatomical 3D models were generated from CT datasets with open-access medical informatics software (3D Slicer) and 3D printed on an FDM 3D printer with minimal thermal deformation (Polylactate, PLA). The finished models were used for preoperative planning of complex orthopaedic operations, including high-energy multifragmentary hip, knee and ankle fractures. The preoperative planning included selecting surgical access, preparing tools and implants, and contouring (pre-bending) metal plates for metallic osteosynthesis. Several parameters, such as operation time, blood loss, intraoperative X-rays, and the achievement of anatomical reduction of the fractures, were observed in order to measure the quality of the operations.Accurate anthropomorphic 3D models representing the spatial properties of the bones can be generated from tomographic imaging studies easily and accurately, even with open-source software. They can be utilised as a tool for preoperatively planning complex orthopaedical operations of the lower limb. Using 3D-printed models allows a patient-specific approach, which leads to good anatomical reduction and favourable functional results in complex surgeries regarding the pelvis, acetabulum, tibial plateau, and calcaneus.The methods described in the paper are routinely used for the preoperative planning of complex orthopaedical operations regarding the lower limb. In the future, they will be combined with the implementation of 3D-printed personalised titanium implants to achieve good anatomical reduction even for the most challenging multigragmental fractures.In the paper, we described the technical aspects and clinical considerations for the preoperative planning of complex orthopaedical operations, which can assist engineers and clinicians alike in implementing the useful method in clinical practice.

Validation of a 3D-printed model of cryptoglandular perianal fistulas.

Visualising the course of a complex perianal fistula on imaging can be difficult. It has been postulated that three-dimensional (3D) models of perianal fistulas improve understanding of the perianal pathology, contribute to surgical decision-making and might even improve future outcomes of surgical treatment. The aim of the current study is to investigate the accuracy of 3D-printed models of perianal fistulas compared with magnetic resonance imaging (MRI). MRI scans of 15 patients with transsphincteric and intersphincteric fistulas were selected and then assessed by an experienced abdominal and colorectal radiologist. A standardised method of creating a 3D-printed anatomical model of cryptoglandular perianal fistula was developed by a technical medical physicist and a surgeon in training with special interest in 3D printing. Manual segmentation of the fistula and external sphincter was performed by a trained technical medical physicist. The anatomical models were 3D printed in a 1:1 ratio and assessed by two colorectal surgeons. The 3D-printed models were then scanned with a 3D scanner. Volume of the 3D-printed model was compared with manual segmentation. Inter-rater reliability statistics were calculated for consistency between the radiologist who assessed the MRI scans and the surgeons who assessed the 3D-printed models. The assessment of the MRI was considered the 'gold standard'. Agreement between the two surgeons who assessed the 3D printed models was also determined. Consistency between the radiologist and the surgeons was almost perfect for classification (κ = 0.87, κ = 0.87), substantial for complexity (κ = 0.73, κ = 0.74) and location of the internal orifice (κ = 0.73, κ = 0.73) and moderate for the percentage of involved external anal sphincter in transsphincteric fistulas (ICC 0.63, ICC 0.52). Agreement between the two surgeons was substantial for classification (κ = 0.73), complexity (κ = 0.74), location of the internal orifice (κ = 0.75) and percentage of involved external anal sphincter in transsphincteric fistulas (ICC 0.77). Our 3D-printed anatomical models of perianal fistulas are an accurate reflection of the MRI. Further research is needed to determine the added value of 3D-printed anatomical models in preoperative planning and education.

Masked stereolithography 3D printing of a brain tissue from an MRI data set

3D printing technology holds tremendous promise for applications in the medical field, particularly in the creation of anatomical models. The accuracy of 3D-printed anatomical models is of utmost importance, especially for surgeons engaged in complex surgical planning. The goal of this study was to create an anatomically precise model of brain tissue using data obtained from an MRI scan, with a resin-based Masked Stereolithography 3D printer, and to assess the model's potential uses. The process of creating an anatomical brain model with an SLA 3D printer was divided into six fundamental stages. The 3D printing process for this project necessitated 55.4 g of resin, and the total printing time was 4 h and 56 min. Any liquid resin residues on the brain structure eliminated through cleaning have been conducted using 99.6 % pure isopropyl alcohol. Following the printing phase, the produced model underwent a curing process in a chamber illuminated with ultraviolet light at a wavelength of 405 nm to ensure complete solidification. Once solidification is completed, the dimensions of the brain are measured with a micrometer and compared with those digitally generated from the MRI scan data. The results showed that the overall dimensional error was less than 1 %.

Quality assurance of 3D-printed patient specific anatomical models: a systematic review

BackgroundThe responsible use of 3D-printing in medicine includes a context-based quality assurance. Considerable literature has been published in this field, yet the quality of assessment varies widely. The limited discriminatory power of some assessment methods challenges the comparison of results. The total error for patient specific anatomical models comprises relevant partial errors of the production process: segmentation error (SegE), digital editing error (DEE), printing error (PrE). The present review provides an overview to improve the general understanding of the process specific errors, quantitative analysis, and standardized terminology.MethodsThis review focuses on literature on quality assurance of patient-specific anatomical models in terms of geometric accuracy published before December 4th, 2022 (n = 139). In an attempt to organize the literature, the publications are assigned to comparable categories and the absolute values of the maximum mean deviation (AMMD) per publication are determined therein.ResultsThe three major examined types of original structures are teeth or jaw (n = 52), skull bones without jaw (n = 17) and heart with coronary arteries (n = 16). VPP (vat photopolymerization) is the most frequently employed basic 3D-printing technology (n = 112 experiments). The median values of AMMD (AMMD: The metric AMMD is defined as the largest linear deviation, based on an average value from at least two individual measurements.) are 0.8 mm for the SegE, 0.26 mm for the PrE and 0.825 mm for the total error. No average values are found for the DEE.ConclusionThe total error is not significantly higher than the partial errors which may compensate each other. Consequently SegE, DEE and PrE should be analyzed individually to describe the result quality as their sum according to rules of error propagation. Current methods for quality assurance of the segmentation are often either realistic and accurate or resource efficient. Future research should focus on implementing models for cost effective evaluations with high accuracy and realism. Our system of categorization may be enhancing the understanding of the overall process and a valuable contribution to the structural design and reporting of future experiments. It can be used to educate specialists for risk assessment and process validation within the additive manufacturing industry.Graphical Context of the figures in this review. Center: Fig. 5+ 7; top (blue): Fig. 8; right (green): Fig. 9; bottom (yellow): Fig. 10; left (red): Fig. 11. A version in high resolution can be found online in the supplementary material.

The Value of Using Patient-Specific 3D-Printed Anatomical Models in Surgical Planning for Patients With Complex Multifibroid Uteri

ObjectivesTo compare surgeon responses regarding their surgical plan before and after receiving a patient-specific three-dimensional (3D)-printed model of a patient’s multifibroid uterus created from their magnetic resonance imaging. Methods3D-printed models were derived from standard-of-care pelvic magnetic resonance images of patients scheduled for surgical intervention for multifibroid uterus. Relevant anatomical structures were printed using a combination of transparent and opaque resin types. 3D models were used for 7 surgical cases (5 myomectomies, 2 hysterectomies). A staff surgeon and 1 or 2 surgical fellow(s) were present for each case. Surgeons completed a questionnaire before and after receiving the model documenting surgical approach, perceived difficulty, and confidence in surgical plan. A postoperative questionnaire was used to assess surgeon experience using 3D models. ResultsTwo staff surgeons and 3 clinical fellows participated in this study. A total of 15 surgeon responses were collected across the 7 cases. After viewing the models, an increase in perceived surgical difficulty and confidence in surgical plan was reported in 12/15 and 7/15 responses, respectively. Anticipated surgical time had a mean ± SD absolute change of 44.0 ± 47.9 minutes and anticipated blood loss had an absolute change of 100 ± 103.5 cc. 2 of 15 responses report a change in pre-surgical approach. Intra-operative model reference was reported to change the dissection route in 8/15 surgeon responses. On average, surgeons rated their experience using 3D models 8.6/10 for pre-surgical planning and 8.1/10 for intra-operative reference. ConclusionsPatient-specific 3D anatomical models may be a useful tool to increase a surgeon’s understanding of complex gynaecologic anatomy and to improve their surgical plan. Future work is needed to evaluate the impact of 3D models on surgical outcomes in gynaecology.

Augmented reality in implantology: Virtual surgical checklist and augmented implant placement

ObjectivesAim of the present study was to create a pedagogical checklist for implant surgical protocol with an augmented reality (AR) guided freehand surgery to inexperienced surgeons using a head mounted display (HMD) with tracking. MethodsThe anatomical model of a patient with two missing mandibular teeth requiring conventional single-tooth implants was selected. The computed tomography (CT) scans were extracted and imported into segmentation and implant planning software. A Patient-specific dental splint through an intermediate strut, supported 3D-printed QR code. A checklist was generated to guide surgical procedure. After tracking, the AR-HMD projects the virtual pre-surgical plan (inferior alveolar nerve (IAN), implant axis, implant location) onto the real 3D-printed anatomical models. The entire drilling sequence was based on the manufacturer's recommendations, on 3D-printed anatomical models. After the implant surgical procedure, CT of the 3D-printed models was performed to compare the actual and simulated implant placements. All procedures in the study were performed in accordance with the Declaration of Helsinki. ResultsIn total, two implants were placed in a 3D-printed anatomical model of a female patient who required implant rehabilitation for dental agenesis at the second mandibular premolar positions (#35 and #45). Superimposition of the actual and simulated implants showed high concordance between them. ConclusionAR in education offers crucial surgical information for novice surgeons in real time. However, the benefits provided by AR in clinical and educational implantology must be demonstrated in other studies involving a larger number of patients, surgeons and apprentices.

Are 3D-printed anatomical models of the ear effective for teaching anatomy? A comparative pilot study versus cadaveric models.

Despite the combination of chalkboard lectures and cadaveric models, the ear remains a complex anatomical structure that is difficult for medical students to grasp. The aim of this study was to evaluate the contribution of a 3D-printed ear model for educating undergraduate medical students by comparing it with a conventional cadaveric model. Models of the ear comprising the outer ear, tympanic membrane, ossicles and inner ear were modeled and then 3D-printed at 6:1 and 10:1 scales based on cadaveric dissection and CT, cone-beam CT and micro/nano CT scans. Cadaveric models included two partially dissected dry temporal bones and ossicles. Twenty-four 3rd year medical students were given separate access to cadaveric models (n = 12) or 3D-printed models (n = 12). A pre-test and two post-tests were carried out to assess knowledge (n = 24). A satisfaction questionnaire focusing solely on the 3D-printed model, comprising 17 items assessed on a 5-point Likert scale, was completed by all study participants. A 5-point Likert scale questionnaire comprising four items (realism, color, quality and satisfaction with the 3D-printed ear model) was given to three expert anatomy Professors. The test scores on the first post-test were higher for the students who had used the 3D-printed models (p < 0.05). Overall satisfaction among the students and the experts was very high, averaging 4.7 on a 5-point Likert-type satisfaction scale. This study highlights the overall pedagogical value of a 3D-printed model for learning ear anatomy.

The Use of In-House Patient-Specific 3D Printed Models in Plastic-, Orthopedic and Neurosurgical Planning: A Preliminary Report

Aim: A limited number of studies have attempted to quantify the advantages of using in-house 3D printed models. We designed a pilot study to assess the value of in-house production of patient-specific 3D-printed models in pre-surgical planning. Methods: A 12-question survey was designed and sent to surgeons to assess any purported benefits of 3D-printed anatomic models. In-house 3D model printing was completed on a Stratasys J750 Polyjet printer. Each 3D printed model was delivered to the supervising surgeon days before the procedure for final validation. The 3D models were subsequently utilized in the operating room. Results: A total of 50 surveys were completed for a response rate of 100%. Approximately 94% of the participants strongly agreed that the 3D-printed model was a valuable clinical tool for pre-surgical planning. The majority of the respondents (78%) reported improved surgical efficiency. Conclusion: 3D models is a valuable tool for surgical planning.

3D-Printed Anatomical Models Allowing for Customization

3D-Printed Anatomical Models Allowing for Customization

Higher Computed Tomography (CT) Scan Resolution Improves Accuracy of Patient-specific Mandibular Models When Compared to Cadaveric Gold Standard

3D-printed patient-specific anatomical models are becoming an increasingly popular tool for planning reconstructive surgeries to treat oral cancer. Currently there is a lack of information regarding model accuracy, and how the resolution of the computed tomography (CT) scan affects the accuracy of the final model. The primary objective of this study was to determine the CT z-axis resolution necessary in creating a patient specific mandibular model with clinically acceptable accuracy for global bony reconstruction. This study also sought to evaluate the effect of the digital sculpting and 3D printing process on model accuracy. This was a cross-sectional study using cadaveric heads obtained from the Ohio State University Body Donation Program. The first independent variable is CT scan slice thickness of either 0.675, 1.25, 3.00, or 5.00mm. The second independent variable is the three produced models for analysis (unsculpted, digitally sculpted, 3D printed). The degree of accuracy of a model as defined by the root mean square (RMS) value, a measure of a model's discrepancy from its respective cadaveric anatomy. All models were digitally compared to their cadaveric bony anatomy using a metrology surface scan of the dissected mandible. The RMS value of each comparison evaluates the level of discrepancy. One-way ANOVA tests (P<.05) were used to determine statistically significant differences between CT scan resolutions. Two-way ANOVA tests (P<.05) were used to determine statistically significant differences between groups. CT scans acquired for 8 formalin-fixed cadaver heads were processed and analyzed. The RMS for digitally sculpted models decreased as slice thickness decreased, confirming that higher resolution CT scans resulted in statistically more accurate model production when compared to the cadaveric gold standard. Furthermore, digitally sculpted models were significantly more accurate than unsculpted models (P<.05) at each slice thickness. Our study demonstrated that CT scans with slice thicknesses of 3.00mm or smaller created statistically significantly more accurate models than models created from slice thicknesses of 5.00mm. The digital sculpting process statistically significantly increased the accuracy of models and no loss of accuracy through the 3D printing process was observed.

Head Phantom for the Acquisition of Pulsatile Optical Signals for Traumatic Brain Injury Monitoring

(1) Background: Tissue phantoms can provide a rigorous, reproducible and convenient approach to evaluating an optical sensor’s performance. The development, characterisation and evaluation of a vascular head/brain phantom is described in this study. (2) Methods: The methodology includes the development of mould-cast and 3D-printed anatomical models of the brain and the skull and a custom-made in vitro blood circulatory system used to emulate haemodynamic changes in the brain. The optical properties of the developed phantom were compared to literature values. Artificial cerebrospinal fluid was also incorporated to induce changes in intracranial pressure. (3) Results: A novel head model was successfully developed to mimic the brain and skull anatomies and their optical properties within the near-infrared range (660–900 nm). The circulatory system developed mimicked normal arterial blood pressure values, with a mean systole of 118 ± 8.5 mmHg and diastole of 70 ± 8.5 mmHg. Similarly, the cerebrospinal fluid circulation allowed controlled intracranial pressure changes from 5 to 30 mmHg. Multiwavelength pulsatile optical signals (photoplethysmograms (PPGs)) from the phantom’s cerebral arteries were successfully acquired. Conclusions: This unique head phantom technology forms the basis of a novel research tool for investigating the relationship between cerebral pulsatile optical signals and changes in intracranial pressure and brain haemodynamics.

Angle bisector method to determine the accurate angle for tibiofibular syndesmotic fixation: A validation study with 3D-printed anatomical models

PurposeThis study aimed to validate the angle bisector method on 3D-printed ankle models to reveal whether it aids in placing syndesmotic screws at an accurate trajectory that is patient- and level-specific and also not surgeon-dependent. MethodsDICOM data of 16 ankles were used to create 3D anatomical models. Then the models were printed in their original size and two trauma surgeons performed the syndesmotic fixations with the angle bisector method at 2 cm and 3.5 cm proximal to joint space. Afterward, the models were sectioned to reveal the trajectory of the screws. The photos of the axial sections were processed in a software to determine the centroidal axis which is defined as true syndesmotic axis and analyze its relationship with the screws inserted. The angle between the centroidal axis and syndesmotic screw was measured by two-blinded observers 2 times with 2 weeks interval. ResultsThe average angle between the centroidal axis and screw trajectory was 2.4° ± 2° at 2 cm-level and 1.3° ± 1.5° at 3.5 cm-level, indicating a reliable direction with minimal differences at both levels. The average distance between fibular entry points of the centroidal axis and screw trajectory was less than 1 mm at both levels indicating that the angle bisector method can provide an excellent entry point from fibula for syndesmotic fixation. The inter- & intra-observer consistencies were excellent with all ICC values above 0.90. ConclusionThe angle bisector method provided an accurate syndesmotic axis for implant placement which is patient- & level-specific and not surgeon-dependent, in 3D-printed anatomical ankle models.

3D-Printed Models for Multidisciplinary Discussion of Congenital Heart Diseases

Background. Congenital heart defects (CHDs) are complex three-dimensional (3D) lesions with variable anatomies that present therapeutic challenges. The application of a patient-specific3D-printed model in preoperative planning and communication in medical practice can contribute to a complete understanding of the intracardiac and vascular anatomy. This study aimed to prospectively investigate the clinical value of a 3D CHD model in multidisciplinary discussions. Methods. Between August 2019 and April 2021, 19 patients with complex CHDs before surgery were prospectively enrolled in this study. Eight to 14 medical specialists participated in multidisciplinary discussions using patient-specific 3D models. A subjective satisfaction questionnaire, comprising 12 questions to be answered on a 10-point scale, was distributed. Results. Twenty 3D-printed anatomic models of 19 patients were used. The median age and weight of the enrolled patients were 0.8 years (range, 5 days to 43 years) and 9.6 kg (range, 2.8–54 kg), respectively. The most common underlying disease was a double outlet of the right ventricle. The mean scores for understanding spatial orientation, ease of communication between clinicians during discussions, prediction of surgical complications, and information additional to conventional 2D imaging were 9.4 ± 1.1, 9.4 ± 0.9, 9.0 ± 1.1, and 9.2 ± 0.4, respectively. The competency and comfort scores for each patient’s surgical plan increased significantly after using the 3D-printed model (from 6.2 ± 1.6 to 9.2 ± 0.9, p &lt; 0.001 and from 6.3 ± 1.6 to 9.2 ± 0.8, p &lt; 0.001, respectively). Conclusions. Patient-specific 3D models, for patients with complex CHDs, improved the understanding of the disease and facilitated multidisciplinary discussions and surgical decision-making. However, because outcomes were mainly evaluated by subjective reports, the possibility of other unknown factors affecting the outcomes should be considered. Trial Registration. This trial is registered with D-1904-031-1024.

Quality assurance in 3D-printing: A dimensional accuracy study of patient-specific 3D-printed vascular anatomical models.

3D printing enables the rapid manufacture of patient-specific anatomical models that substantially improve patient consultation and offer unprecedented opportunities for surgical planning and training. However, the multistep preparation process may inadvertently lead to inaccurate anatomical representations which may impact clinical decision making detrimentally. Here, we investigated the dimensional accuracy of patient-specific vascular anatomical models manufactured via digital anatomical segmentation and Fused-Deposition Modelling (FDM), Stereolithography (SLA), Selective Laser Sintering (SLS), and PolyJet 3D printing, respectively. All printing modalities reliably produced hand-held patient-specific models of high quality. Quantitative assessment revealed an overall dimensional error of 0.20 ± 3.23%, 0.53 ± 3.16%, -0.11 ± 2.81% and -0.72 ± 2.72% for FDM, SLA, PolyJet and SLS printed models, respectively, compared to unmodified Computed Tomography Angiograms (CTAs) data. Comparison of digital 3D models to CTA data revealed an average relative dimensional error of -0.83 ± 2.13% resulting from digital anatomical segmentation and processing. Therefore, dimensional error resulting from the print modality alone were 0.76 ± 2.88%, + 0.90 ± 2.26%, + 1.62 ± 2.20% and +0.88 ± 1.97%, for FDM, SLA, PolyJet and SLS printed models, respectively. Impact on absolute measurements of feature size were minimal and assessment of relative error showed a propensity for models to be marginally underestimated. This study revealed a high level of dimensional accuracy of 3D-printed patient-specific vascular anatomical models, suggesting they meet the requirements to be used as medical devices for clinical applications.

Particle Image Velocimetry of 3D-Printed Anatomical Blood Vascular Models Affected by Atherosclerosis.

Improvements in the diagnosis and treatment of cardiovascular diseases facilitate a better understanding of the ongoing process. The study of biomedical fluid dynamics using non-intrusive visualizing methods on a micro-scale has become possible using a proper 3D printing process. The computed tomography scan of a patient with atherosclerosis was processed, and a 3D-printed artery with an inlet diameter of 4.2 mm was developed and measured using three different constant flow rates. To mimic blood, a solution of glycerin and water was used. The procedure to obtain a proper 3D-printed model using low-force stereolithography technology with high-quality optical access usable for PIV was described and discussed. The paper presents the results of PIV as multi-stitched, color-coded vector maps from the axis cross section along the whole 3D-printed model. The obtained data allowed a resolution of 100 × 100 µm per single vector to be achieved. Furthermore, the results of the stitched 16 base images of the artery and the 3D-printed model prepared were included. The results of this study show that 3D prints allow for the creation of the desired geometry and can be used to investigate severe pathologies of the human circulatory system. The strengths and weaknesses of this methodology were discussed and compared to other techniques used to obtain transparent objects.

3D Printing in Surgical Planning and Intra-Operative Assistance: A Case Report on Cervical Deformity Correction Surgery

Three-dimensional (3D)-printed anatomical models of the bones play a key role in complex surgical procedures. These subject-specific physical models are valuable in pre-operative planning and may also offer assistance during surgery by improving the visibility of inaccessible anatomical structures, particularly in spine surgery. Starting from medical imaging, virtual 3D bone models are reconstructed, and these can also be used for quantifying original, planned, and achieved bone-to-bone alignments. The purpose of this study is to report on an original exploitation of these techniques on a patient with a severe cervical deformity to undergo corrective and stabilizing surgery. A virtual anatomical model of the cervical spine before surgery was obtained from computer tomography to assess the original deformity and for surgical planning. The corresponding 3D model was printed in acrylonitrile-butadiene-styrene and used to simulate the surgery by performing bone cuts, implanting the screws, and placing and shaping the fixation elements. During surgery, this physical 3D-printed model was used as a reference for each surgical action. The comparisons between pre- and post-operative virtual models confirmed that the planned correction was achieved. Virtual and 3D-printed anatomical models of the cervical spine offer advantages in the planning and execution of personalized complex surgeries, in addition to improving surgical safety.