Biomechanical analysis of push-pull principle versus traditional approach in locking plates for proximal humeral fracture treatment.

INTRODUCTION: Proximal humerus fractures are usually treated with locking plates, which could present recurrence, screw penetration, joint varization. The push-pull principle was introduced to prevent these risks and showed promising results; a dedicated design was then developed and this feasibility study aims to compare the biomechanical performances of such dedicated push-pull plate with the traditional locking plate using finite elements. MATERIALS AND METHODS: The humerus geometry was obtained from Sawbone CT-scans; the geometries of a traditional locking plate and of the dedicated push-pull one were used. A fracture was added below the humeral head and the plates were virtually implanted. The wire pulling mechanism was simulated connecting the plate to the humeral head apex, considering two levels of tension. Three testing set-ups (axial, torsion and compression bending) were simulated. Stress distributions on bone, plate and screws were measured. RESULTS: Stress distribution on the distal humerus was similar for both plates. Stress distribution on the proximal humerus was more homogeneous for the push-pull model, showing less unloaded sections (up to 78%). The different levels of tension applied to the wire returned slight differences in terms of stress values, but the comparison with the traditional approach gave similar outcomes. CONCLUSIONS: More homogeneous stress distribution is found with the push-pull plate in all three testing set-ups, showing lower unloaded areas (and thus lower stress-shielding) compared to the traditional plate; the screws implemented returned to be all loaded in at least one of the set-ups, thus showing that they all contribute to plate stability.

Mathematical explanations for knee osteotomies: "Dear engineer, how would you explain it in a simple way?"

INTRODUCTION: Knee osteotomies are effective procedures to treat different deformities and to redistribute the load at the joint level, reducing the risk of wear and, consequently, the need for invasive procedures. Particularly, knee osteotomies are effective in treating early arthritis related to knee deformities in young and active patients with high functional demands, with excellent long-term results. Precise mathematical calculations are imperative during the preoperative phase to achieve tailored and accurate corrections for each patient and avoid complications, but sometimes those formulas are challenging to comprehend and apply. METHODS: Four specific questions regarding controversial topics (planning methods, patellar height, tibial slope, and limb length variation) were formulated. An electronic search was performed on PubMed and Cochrane Library to find articles containing detailed mathematical or trigonometrical explanations. A team of orthopedic surgeons and an engineer summarized the available Literature and mathematical rules, with a final clear mathematical explanation given by the engineer. Wherever the explanation was not available in Literature, it was postulated by the same engineer. RESULTS: After the exclusion process, five studies were analyzed. For three questions, no studies were found that provided mathematical analyses or explanations. Through independent calculations, it was demonstrated why Dugdale's method underestimates the correction angle compared to Miniaci's method, and it was shown that the variation in patellar height after osteotomy can be predicted using simple formulas. The five included studies examine postoperative variations in limb length and tibial slope, providing formulas applicable in preoperative planning. New formulas were independently computed, using the planned correction angle and preoperatively obtained measurements to predict the studied variations. CONCLUSIONS: There is a strict connection among surgery, planning, and mathematics formulas in knee osteotomies. The aim of this study was to analyze the current literature and provide mathematical and trigonometric explanations to important controversial topics in knee osteotomies. Simple and easy applicable formulas are provided to enhance the accuracy and outcomes of this surgical procedure.

Advancing Surgical Arrhythmia Ablation: Novel Insights on 3D Printing Applications and Two Biocompatible Materials.

To date, studies assessing the safety profile of 3D printing materials for application in cardiac ablation are sparse. Our aim is to evaluate the safety and feasibility of two biocompatible 3D printing materials, investigating their potential use for intra-procedural guides to navigate surgical cardiac arrhythmia ablation. Herein, we 3D printed various prototypes in varying thicknesses (0.8 mm-3 mm) using a resin (MED625FLX) and a thermoplastic polyurethane elastomer (TPU95A). Geometrical testing was performed to assess the material properties pre- and post-sterilization. Furthermore, we investigated the thermal propagation behavior beneath the 3D printing materials during cryo-energy and radiofrequency ablation using an in vitro wet-lab setup. Moreover, electron microscopy and Raman spectroscopy were performed on biological tissue that had been exposed to the 3D printing materials to assess microparticle release. Post-sterilization assessments revealed that MED625FLX at thicknesses of 1 mm, 2.5 mm, and 3 mm, along with TPU95A at 1 mm and 2.5 mm, maintained geometrical integrity. Thermal analysis revealed that material type, energy source, and their factorial combination with distance from the energy source significantly influenced the temperatures beneath the 3D-printed material. Electron microscopy revealed traces of nitrogen and sulfur underneath the MED625FLX prints (1 mm, 2.5 mm) after cryo-ablation exposure. The other samples were uncontaminated. While Raman spectroscopy did not detect material release, further research is warranted to better understand these findings for application in clinical settings.

Gross Taper Failure and Fracture of the True Neck in Total Hip Arthroplasty: Retrieval Scanning Electron Microscope Analysis.

Background and objectives: wear and corrosion can lead to the gross failure of the Morse taper junction with the consequent fracture of the true neck of the prosthetic stem in hip arthroplasty. Materials and Methods: 58-year-old male patient, with a BMI of 38 kg/m2. Because of avascular necrosis, in 2007, a metal-on-metal total hip arthroplasty was implanted in him, with a TMZF stem and a Co-Cr head. In December 2020, he complained of acute left hip pain associated with the deterioration of his left leg and total functional impairment, preceded by the crunching of the hip. X-rays and CT scan showed a fracture of the prosthetic neck that necessitated prosthetic revision surgery. A Scanning Electron Microscope (SEM) analysis of the retrieved prosthetic components was conducted. Results: Macroscopically, the trunnion showed a typical bird beak appearance, due to a massive material loss of about half of its volume. The gross material loss apparently due to abrasion extended beyond the trunnion to the point of failure on the true neck about half a centimeter distal from the taper. SEM analysis demonstrated fatigue rupture modes, and the crack began close to the neck's surface. On the lateral surface, several scratches were found, suggesting an intense wear that could be due to abrasion. Conclusions: The analysis we conducted on the explanted THA showed a ductile rupture, began close to the upper surface of the prosthetic neck where the presence of many scratches had concentrated stresses and led to a fatigue fracture.

Are Flexible Metaphyseal Femoral Cones Stable and Effective? A Biomechanical Study on Hinged Total Knee Arthroplasty.

BACKGROUND: Cones currently available in the market are rigid, and unless they are custom-specific designed, are unable to correctly adapt to the shape of the patient's bone. Therefore, flexible metaphyseal cones have been recently introduced to reduce potential bone trauma during implantation. Even if a preliminary clinical study on their use has shown promising results, no biomechanical study evaluates and quantifies their mechanical efficacy and safety. METHODS: Two commercial versions of flexible cones were analyzed in this study using finite element analysis, based on a previously validated model. Each cone geometry was modeled both as flexible and as rigid, and implanted following surgical guidelines. Three activities were simulated in this study and compared among configurations: surgical impaction, walking, and chair rise. RESULTS: During impaction, results showed considerably reduced stress in the flexible cones in comparison with rigid ones; the stress resulted was also better distributed and more homogeneous all over the cortical bone, with lower bone peaks. Considering the 2 different activities, the analysis did not show any remarkable differences between flexible and rigid cones both in terms of bone stress and implant micromotion. CONCLUSIONS: The findings demonstrate that metaphyseal flexible cones allow macrodeformation during impaction due to their flexibility, and therefore, are safer in comparison with rigid cones. However, for the daily tasks investigated, results showed no major differences between rigid and flexible cones in terms of bone stress, implant stability, and micromotion. Therefore, their mechanical performances can be considered similar to the rigid cone.

Is Total Knee Arthroplasty Surgical Performance Enhanced Using Augmented Reality? A Single-Center Study on 76 Consecutive Patients.

BACKGROUND: Augmented reality (AR) is a powerful multipurpose tool. With a dedicated visor, AR allows the visualization of a series of information and/or images superimposed on the user's field of vision. For this reason, it was recently introduced as a surgical assistant tool. This single-center study aimed to evaluate the intraoperative outcomes of total knee arthroplasties performed with AR assistance in terms of time required and the difference between preplanned and achieved implant positioning (in terms of tibial cut varus and slope angles). METHODS: A total of 76 consecutive patients was selected. Preplanning was performed according to the AR protocol, and the target varus and slope angles were defined to instruct the device, which subsequently guided the tibial cuts intraoperatively. Surgeries were performed starting from the tibial cut, and the time required to perform the calibration, registration, and fixation of the resection block was recorded. The varus and slope angles achieved were recorded to compare with the preplanned ones to determine the means and SDs of the differences. RESULTS: The mean usage time of the AR tool was 5 ± 1 minutes. Results showed a mean difference of 0.59 ± 0.55° for varus angles and 0.70 ± 0.75° for the slope. For varus angles, the differences were <1° for 96% of the cases. Concerning the slope, 89% of the cases were <1°. CONCLUSION: The results showed excellent accuracy of the surgical cuts and a limited increase in surgery duration. Therefore, these outcomes highlighted the potential of this new technology as a valid option for surgical assistance.

Acute effects of a chewable beetroot-based supplement on cognitive performance: a double-blind randomized placebo-controlled crossover clinical trial.

BACKGROUND: Dietary nitrate (NO3-) has been shown to be useful as an ergogenic aid with potential applications in health and disease (e.g., blood pressure control). However, there is no consensus about the effects of dietary NO3- or beetroot (BR) juice supplementation on cognitive function. OBJECTIVE: The aim of this study was to evaluate the effects of a single dose of a chewable BR-based supplement on cognitive performance. METHODS: A double-blind randomized placebo-controlled two-period crossover clinical trial was carried out based on the extension of the CONSORT guidelines for randomized crossover trials. A total of 44 participants (24 F; 20 M; 32.7 [12.5] years; 66.3 [9.0] kg; 170 [9.2] cm; 22.8 [1.4] kg/m2) were randomly allocated to receive first either four BR-based chewable tablets (BR-CT) containing 3 g of a Beta vulgaris extract (RedNite®) or four tablets of a placebo (maltodextrin). A 4-day washout period was used before crossover. Ninety minutes after ingestion of the treatments, a neuropsychological testing battery was administered in each period. The trial was registered at clinicaltrials.gov NCT05509075. RESULTS: Significant improvements with moderate effect size were found on memory consolidation at the short and long term only after BR-CT supplementation via the Rey Auditory Verbal Learning Test immediate (+ 20.69%) and delayed (+ 12.34%) recalls. Likewise, enhancement on both frontal lobe functions (+ 2.57%) and cognitive flexibility (+ 11.16%) were detected after BR-CT. There was no significant change (p < 0.05) on verbal memory of short-term digits, working memory and information processing speed. Mixed results were found on mood and anxiety through the Beck Depression Inventory-II (BDI-II) and the State-Trait Anxiety Inventory (STAI-Y1 and STAI-Y2); however, sequence and period effects were seen on STAI-Y2. CONCLUSIONS: The acute administration of a chewable BR-based supplement improves certain aspects of cognitive function in healthy females and males, particularly memory capacity and frontal skills.

Covariations between scapular shape and bone density in B-glenoids: A statistical shape and density modeling-approach.

B-type glenoids are characterized by posterior humeral head migration and/or bony-erosion-induced glenoid retroversion. Patients with this type of osteoarthritic glenoids are known to be at increased risk of glenoid component loosening after anatomic total shoulder arthroplasty (aTSA). One of the main challenges in B glenoid surgical planning is to find a balance between correcting the bony shape and maintaining the quality of the bone support. This study aims to systematically quantify variabilities in terms of scapular morphology and bone mineral density in patients with B glenoids and to identify patterns of covariation between these two features. Using computed tomography scan images of 62 patients, three-dimensional scapular surface models were constructed. Rigid and nonrigid surface registration of the scapular surfaces, followed by volumetric registration and material mapping, enabled us to develop statistical shape model (SSM) and statistical density model (SDM). Partial least square correlation (PLSC) was used to identify patterns of covariation. The developed SSM and SDM represented 85.9% and 56.6% of variabilities in terms of scapular morphology and bone density, respectively. PLSC identified four modes of covariation, explaining 66.0% of the correlation between these two variations. Covariation of posterior-inferior glenoid erosion with posterior sclerotic bone formation in association with reduction of bone density in the anterior and central part of the glenoid was detected as the primary mode of covariation. Identification of these asymmetrical distribution of bone density can inform us about possible reasons behind glenoid component loosening in B glenoids and surgical guidelines in terms of the compromise between bony shape correction and bone support quality.

Biomechanical analysis of different THA cementless femoral stem designs in physiological and osteoporotic bone during static loading conditions.

BACKGROUND: The influence of THA stem design on periprosthetic femoral fractures (PFFs) risk is subject of debate. This study aims to compare the effects of different cementless stem designs on stress-strain distributions in both physiological and osteoporotic femur under various loading conditions. MATERIALS: A biomechanical study using finite-element analysis was conducted. Four models were developed: three with implanted femurs and a native one chosen as control. Each model was analyzed for both healthy and osteoporotic bone. The following stem designs were examined: short anatomical stem with femoral neck preservation, double-wedge stem, and anatomical standard stem. Three loading conditions were assessed: gait, sideways falling, and four-point bending. RESULTS: During gait in physiological bone, the anatomical stem and the short anatomical stem with femoral neck preservation showed stress distribution similar to the native model. The double-wedge stem reduced stress in the proximal area but concentrated it in the meta-diaphysis. In osteoporotic bone, the double-wedge stem design increased average stress by up to 10%. During sideways falling, the double-wedge stem exhibited higher stresses in osteoporotic bone. No significant differences in average stress were found in any of the studied models during four-point bending. CONCLUSION: In physiological bone, anatomical stems demonstrated stress distribution comparable to the native model. The double-wedge stem showed uneven stress distribution, which may contribute to long-term stress shielding. In the case of osteoporotic bone, the double-wedge stem design resulted in a significant increase in average stress during both gait and sideways falling, potentially indicating a higher theoretical risk of PFF.

The Effects of Different Femoral Component Materials on Bone and Implant Response in Total Knee Arthroplasty: A Finite Element Analysis.

Due to the high stiffness of the biomaterials used in total knee arthroplasty, stress shielding can lead to decreased periprosthetic bone mineral density and bone resorption. As different materials and 3D-printed highly porous surfaces are available for knee femoral components from the industry nowadays, this study aimed to compare the effects of two same-design cruciate-retaining femoral components, made with CoCr and titanium alloy, respectively, on periprosthetic bone stresses through a finite element model of the implanted knee in order to evaluate the induced stress shielding. Moreover, the effect of the cementless highly porous surface of the titanium implant was analyzed in comparison to the cemented interface of the CoCr implant. The von Mises stresses were analyzed in different periprosthetic regions of interest of the femur with different configurations and knee flexion angles. The titanium component induced higher bone stresses in comparison with the CoCr component, mostly in the medial compartment at higher knee flexion angles; therefore, the CoCr component led to more stress shielding. The model was revealed to be effective in describing the effects of different femoral component materials on bone stress, highlighting how a cementless, highly porous titanium femoral component might lead to less stress shielding in comparison to a cemented CoCr implant with significant clinical relevance and reduced bone resorption after total knee arthroplasty.

How reproducible are clinical measurements in robotic knee surgery?

PURPOSE: Robotic-assisted surgery has been recently introduced to improve biomechanical restoration, and thus better clinical and functional outcomes, after knee joint arthroplasty operations. Robotic-assisted uni-compartmental knee arthroplasty (UKA) aims indeed to improve surgical bone resection and alignment accuracy, optimized component positioning and knee balancing, relying on a series of calibration measurements performed during the surgery. These advantages focus therefore on improving the reproducibility of UKA surgeries, reducing (if not eliminating) eventual differences among high- and low-volume surgeons. The purpose of this study is to investigate and quantify the reproducibility of in-vivo measurements performed with a robotic system: the intra- and inter-observer variability of a series of measurements was therefore analyzed and compared among differently experienced operators. METHODS: Five patients were analyzed and underwent robotic-assisted UKA using a semi-active robotic system. Three different observers with different experience levels were involved to independently perform the measurements of two parameters of the preoperative knee (Hip-Knee-Ankle angle [HKAa], Internal-External Rotation) at different degrees of knee flexion. Inter-observer and intra-observer comparisons were performed. RESULTS: The average variability in the measurements obtained from the intra-observer and inter-observer comparisons were always < 0.68° for HKAa and < 2.59° for internal-external rotation, and the ICCs showed excellent agreement (> 0.75) for most cases and good agreement (> 0.60) in the remaining ones. CONCLUSION: This study demonstrated high reproducibility of the measurements obtainable in clinical environment with the robotic system. The inter-observer results furthermore showed that the level of confidence with the robotic system is not significantly influencing the measurement.

3D-Printed Biomaterial Testing in Response to Cryoablation: Implications for Surgical Ventricular Tachycardia Ablation.

Background: The lack of thermally and mechanically performant biomaterials represents the major limit for 3D-printed surgical guides, aimed at facilitating complex surgery and ablations. Methods: Cryosurgery is a treatment for cardiac arrhythmias. It consists of obtaining cryolesions, by freezing the target tissue, resulting in selective and irreversible damage. MED625FLX and TPU95A are two biocompatible materials for surgical guides; however, there are no data on their response to cryoenergy delivery. The study purpose is to evaluate the biomaterials' thermal properties, examining the temperature changes on the porcine muscle samples (PMS) when the biomaterials are in place during the cryoablation. Two biomaterials were selected, MED625FLX and TPU95A, with two thicknesses (1.0 and 2.5 mm). To analyze the biomaterials' behavior, the PMS temperatures were measured during cryoablation, firstly without biomaterials (control) and after with the biomaterials in place. To verify the biomaterials' suitability, the temperatures under the biomaterial samples should not exceed a limit of -30.0 °C. Furthermore, the biomaterials' geometry after cryoablation was evaluated using the grid paper test. Results: TPU95A (1.0 and 2.5 mm) successfully passed all tests, making this material suitable for cryoablation treatment. MED625FLX of 1.0 mm did not retain its shape, losing its function according to the grid paper test. Further, MED625FLX of 2.5 mm is also suitable for use with a cryoenergy source. Conclusions: TPU95A (1.0 and 2.5 mm) and MED625FLX of 2.5 mm could be used in the design of surgical guides for cryoablation treatment, because of their mechanical, geometrical, and thermal properties. The positive results from the thermal tests on these materials and their thickness prompt further clinical investigation.

Biomechanical analysis of different levels of constraint in TKA during daily activities.

BACKGROUND: Numerous total knee prosthetic implants are currently available on the orthopedic market, and this variety covers a set of different levels of constraint: among the various models available, a significant role is covered by mobile bearing cruciate-retaining design with an ultra-congruent insert, mobile bearing cruciate-retaining design, fixed-bearing posterior stabilized prosthesis and fixed-bearing constrained condylar knee. A biomechanical comparative study among them could therefore be helpful for the clinical decision-making process. This study aimed to compare the effect of these different levels of constraint in the knee biomechanics of a patient, in three different configurations representing the typical boundary conditions experienced by the knee joint during daily activities. METHOD: The investigation was performed via finite element analysis with a knee model based on an already published and validated one. Four different types of prosthesis designs were analyzed: two mobile-bearing models and two fixed-bearing models, each one having a different level of constraint. The different designs were incorporated in to the 3D finite element model of the lower leg and analyzed in three different configurations reproducing the landing and the taking-off phases occurring during the gait cycle and chair-rising. Implant kinetics (in terms of polyethylene contact areas and contact pressure), polyethylene and tibial bone stresses were calculated under three different loading conditions for each design. RESULTS: The tibial stress distribution in the different regions of interest of the tibia remains relatively homogeneous regardless of the type of design used. The main relevant difference was observed between the mobile and fixed-bearing models, as the contact areas were significantly different between these models in the different loading conditions. As a consequence, significant changes in the stress distribution were observed at the interface between the prosthetic components, but no significant changes were noted on the tibial bone. Moreover, the different models exhibited a symmetrical medial and lateral distribution of the contact areas, which was not always common among all the currently available prostheses (i.e. medial pivot designs). CONCLUSION: The changes of the prosthetic implant did not induce a big variation of the stress distribution in the different regions of the tibial bone, while they significantly changed the distribution of stress at the interface between the prosthetic components.

Evaluation of photogrammetry for medical application in cardiology.

Background: In the field of medicine, photogrammetry has played for long time a marginal role due to the significant amount of work required that made it impractical for an extended medical use. Developments in digital photogrammetry occurred in the recent years, that have steadily increased the interest and application of this technique. The present study aims to compare photogrammetry reconstruction of heart with computed tomography (CT) as a reference. Methods: The photogrammetric reconstructions of digital images from ECG imaging derived images were performed. In particular, the ventricles of 15 patients with Brugada syndrome were reconstructed by using the free Zephyr Lite software. In order to evaluate the accuracy of the technique, measurements on the reconstructions were compared to patient-specific CT scan imported in ECG imaging software UZBCIT. Result: The results showed that digital photogrammetry in the context of ventricle reconstruction is feasible. The photogrammetric derived measurements of ventricles were not statistically different from CT scan measurements. Furthermore, the analysis showed high correlation of photogrammetry reconstructions with CT scan and a correlation coefficient close to 1. Conclusion: It is possible to reproduce digital objects by photogrammetry if the process described in this study is performed. The reconstruction of the ventricles from CT scan was very close to the values of the respective photogrammetric reconstruction.

Finite element analysis of malposition in bi-unicompartmental knee arthroplasty.

PURPOSE: Bi-unicompartmental knee arthroplasty is a less invasive treatment than a total one, great advantage for the patient but more difficult for the surgeon because of the lower visibility during surgery; this can therefore lead to eventual small errors in cutting angles during the procedure. The aim of this study is to investigate the effects of these slight angle variations in terms of anterior-posterior slope for the lateral tibial tray. METHODS: The geometries of the bones were acquired and uncemented fixed bearing metal-back UKAs virtually implanted in a finite elements environment. The lateral component was implanted in six different antero-posterior slope configurations (from - 5° to + 5° respect to medial component). Material properties for implant, bones and soft tissues were taken from the literature. A vertical compressive force of 2000 N was applied in full-extended configuration on the femur. Von Mises stress distribution in proximal tibia, load/pressure/contact area repartitions between the medial and lateral compartments was extracted as outputs. RESULTS: Outcomes for 0° and - 3° configurations are acceptable, but the - 2° of slope configuration achieved the best ones in terms of stress on proximal tibia, load repartition, contact pressure distribution and shear component. Drastically different results are found for the ± 5° configurations, presenting a level of unbalancing often associated with weak stability and failure over time. CONCLUSIONS: Slight errors can happen during the surgery: performing the cut aiming to slightly posterior slopes during the surgery helps to minimize the chances of obtaining positive slopes that could lead to an unstable implant.

A 3D-printed surgical guide for ischemic scar targeting and ablation.

Background: 3D printing technology development in medical fields allows to create 3D models to assist preoperative planning and support surgical procedures. Cardiac ischemic scar is clinically associated with malignant arrhythmias. Catheter ablation is aimed at eliminating the arrhythmogenic tissue until the sinus rhythm is restored. The scope of this work is to describe the workflow for a 3D surgical guide able to define the ischemic scar and target catheter ablation. Materials and methods: For the patient-specific 3D surgical guide and 3D heart phantom model realization, both CT scan and cardiac MRI images were processed; this was necessary to extract anatomical structures and pathological information, respectively. Medical images were uploaded and processed in 3D Slicer. For the surgical guide modeling, images from CT scan and MRI were loaded in Meshmixer and merged. For the heart phantom realization, only the CT segmentation was loaded in Meshmixer. The surgical guide was printed in MED625FLX with Polyjet technology. The heart phantom was printed in polylactide with FDM technology. Results: 3D-printed surgical model was in agreement with prespecified imputed measurements. The phantom fitting test showed high accuracy of the 3D surgical tool compared with the patient-specific reproduced heart. Anatomical references in the surgical guide ensured good stability. Ablation catheter fitting test showed high suitability of the guide for different ablation tools. Conclusion: A 3D-printed guide for ventricular tachycardia ablation is feasible and accurate in terms of measurements, stability, and geometrical structure. Concerning clinical use, further clinical investigations are eagerly awaited.

Development of a 3D printed surgical guide for Brugada syndrome substrate ablation.

Background: Brugada syndrome (BrS) is a disease associated with ventricular arrhythmias and sudden cardiac death. Epicardial ablation has demonstrated high therapeutic efficacy in preventing ventricular arrhythmias. The purpose of this research is to define a workflow to create a patient-specific 3D-printed tool to be used as a surgical guide for epicardial ablation in BrS. Methods: Due to their mechanical properties and biocompatibility, the MED625FLX and TPU95A were used for cardiac 3D surgical guide printing. ECG imaging was used to define the target region on the right ventricular outflow tract (RVOT). CT scan imaging was used to design the model based on patient anatomy. A 3D patient-specific heart phantom was also printed for fitting test. Sterilization test was finally performed. Results: 3D printed surgical models with both TPU95A and MED625FLX models were in agreement with pre-specified imputed measurements. The phantom test showed retention of shape and correct fitting of the surgical tool to the reproduced phantom anatomy, as expected, for both materials. The surgical guide adapted to both the RVOT and the left anterior descending artery. Two of the 3D models produced in MED265FLX showed damage due to the sterilization process. Conclusions: A 3D printed patient-specific surgical guide for epicardial substrate ablation in BrS is feasible if a specific workflow is followed. The design of the 3D surgical guide ensures proper fitting on the heart phantom with good stability. Further investigations for clinical use are eagerly awaited.