3D printing in medicine最新文献

Background: Atherosclerosis is a chronic disease characterized by the narrowing and hardening of arteries that may induce serious complications and even sudden death. Percutaneous angioplasty is performed as the main treatment of atherosclerotic-based cardiovascular diseases, which are the leading cause of mortality worldwide. Patient-specific physical models of these vascular conditions would greatly assist percutaneous angioplasty medical training and planning. Such models must be composed of materials that accurately replicate the properties of tissues. However, this mimicking can be challenging due to the complexity and composition of atherosclerotic vasculature. As additive manufacturing allows the production of complex and personalized structures, it provides great potential for manufacturing those models. The application of additive manufacturing in this context is often associated with high production costs, mainly related to material synthesis. Commercial materials could break this limitation, but they are still misaddressed.

Methods: Therefore, this work intends to explore the use of three different commercial UV-curable resins to mimic the several types of atherosclerotic vessels. They were manufactured by vat photopolymerisation process, specifically the stereolithography (SLA) technology to mimic atherosclerotic vessels. The mechanical performance of materials and the influence of immersion in phosphate buffered saline (PBS) solution and irradiation with UV light, during different times, were evaluated. Dynamic tensile tests were conducted to study the fatigue resistance of materials under physiological loads.

Results: The results showed that immersion in PBS solution enhanced the dynamic mechano-stability. Likewise, irradiation with UV-C light was pointed out as an interesting strategy to adjust the hardness of materials, with the advantage of being a fast and low-cost approach.

Conclusion: Comparisons with the literature supported that all used materials are suitable for mimicking the mechanical properties of atherosclerotic vessels, specifically when previously immersed in physiological-simulated fluids, such as PBS.

Background: Patients who undergo decompressive craniectomy (DC) are at increased risk of head trauma due to postoperative cranial defects, which not only raise concerns about physical vulnerability but also negatively impact psychological well-being. Conventional protective strategies remain insufficient. This study aimed to develop a personalized, low-cost, three-dimensional (3D) printed external head protection device using mirror-image modeling, and to evaluate its performance in providing physical protection and improving patient-reported outcomes during the post-discharge period.

Method: A prospective study was conducted involving 58 patients treated with DC between August 2023 and February 2025 across two neurosurgical centers. Participants were randomly assigned to an observation group (n = 28), who wore a custom-designed 3D printed protective device based on postoperative CT scans, or to a control group (n = 30) without special protective measures. A custom questionnaire was used to assess satisfaction with appearance, willingness to engage in social activities, and fear of accidental impact at weeks 1, 4, and 8 post-discharge. Objective indicators such as fall events, adverse reactions, and device integrity were also recorded.

Results: The 3D printed models demonstrated good anatomical fit and structural reliability. At weeks 4 and 8, the observation group showed significantly higher Visual Analog Scale (VAS) scores compared to the control group (P = 0.014 and P = 0.002, respectively), with continuous improvement over time (P < 0.05). The average daily usage time of the device was 4.4 ± 1.2 h. No cases of skin irritation or pressure injuries were reported. One patient in the observation group experienced a fall that caused a minor device crack but no head injury (fall rate: 3.6%). In the control group, two patients fell without head trauma (fall rate: 6.7%).

Conclusions: Our findings introduce a personalized, 3D printed external helmet as a new option for cranial protection after decompressive craniectomy. The prototype provided reliable mechanical shielding, conformed closely to each patient's skull contour, and was well tolerated. By reducing physical risk, boosting confidence in appearance, and alleviating anxiety during the interval before cranioplasty, the device may bridge a critical safety and psycho-social gap in early rehabilitation.

Background: Segmental mandibulectomy and mandibular reconstruction are often performed for various benign and malignant head and neck conditions. Standard of care reconstruction involves titanium plate fixation with tissue transfer. The advent of computer-aided design and manufacturing (CAD/CAM) has enhanced aesthetic and functional outcomes in mandibular reconstruction by enabling patient-specific solutions like 3D-printed anatomic models. At an increasing number of institutions, these solutions can be produced in-house via point-of-care manufacturing. Since little has been published on the accuracy and outcomes of this approach, this study sought to evaluate the reconstructive accuracy and clinical outcomes of patients who received in-house patient-specific mandible models.

Methods: A retrospective chart review was conducted of 44 patients from a large midwestern academic medical center who received point-of-care patient-specific 3D printed models to assist in segmental mandibulectomy and reconstruction from December 2020 to June 2022. CAD/CAM models were produced from pre- and post-operative CT scans. Pre- and post-operative scans were aligned using a novel reference landmark-the maxilla. Measurements were taken by two different researchers at the mandibular condyles, coronoids, angles as well as a plane from the maxilla to the mandibular pogonion to determine reconstructive accuracy. Inter-rater reliability was assessed via intraclass correlation coefficient. Demographic, clinical, surgical, and radiographic variables were also collected to profile cohort characteristics and outcomes.

Results: After exclusions due to poor or no post-operative imaging, 25 patients were included in the final analysis. Squamous cell carcinoma (n = 19) was the most common pathology, and males (n = 18) were represented more than females (n = 7). 96% (24/25) of patients had good plate adaptation and 96% (24/25) had good osteotomy adaptation. Reconstruction accuracy measured by comparing preoperative to postoperative anatomic alignment was very good, with an average absolute difference across all patients of only 3.10 mm. Inter-rater reliability between measurements was high with an average 0.98 intraclass correlation coefficient.

Conclusions: We present a novel method for measuring mandibular reconstruction accuracy through the use of the maxilla as the anatomic landmark. Furthermore, our profile of patients who underwent segmental mandibulectomy and reconstruction with the assistance of in-house produced 3D printed patient-specific models appears to result in suitable anatomic alignment of the reconstructed mandible and produce good clinical outcomes.

This study introduces an advanced framework that integrates biphasic cell differentiation bone remodeling theory with finite element (FE) analysis and multi-remodeling simulation to evaluate the performance of 3D-printed biodegradable scaffolds for bone defect repair. The program incorporates a time-dependent cell differentiation stimulus (S), accounting for fluid-phase shear stress and solid-phase shear strain, to dynamically predict bone cell behavior. The study focuses on polylactic acid (PLA) and polycaprolactone (PCL) scaffolds with diamond (DU) and random (YM) lattice designs, applied to a dorsal double-plating (DDP) fixation model for distal radius fractures. Material testing reveals that PLA provides higher rigidity and strength, while PCL offers superior ductility. Mechanical strength tests confirm the superior performance of DU lattice structures under compression, shear, and torsion forces. The bone remodeling program, applied to 36 model combinations of fracture gaps, materials, and lattice designs, computes the total percentage of cell differentiation (TPCD), identifying scaffold material as the key factor, with PLA significantly enhancing TPCD values. Biomechanical analysis after 50 remodeling iterations in a 5.4 mm fracture gap shows that the PLA + DU scaffold reduces displacement by 35%/39%/75%, bone stress by 19%/16%/67%, and fixation plate stress by 77%/66%/93% under axial/bending/torsion loads, respectively, compared to the PCL + YM scaffold. This study highlights the critical role of dynamic remodeling programs in optimizing scaffold material properties and lattice architectures, establishing a robust platform for patient-specific bone repair solutions in regenerative medicine.

Background: The use of 3D-printed hemodynamic phantom of a stenotic carotid artery has not been extensively investigated. Our study aims to address this gap by exploring the correlation between CTA and flow parameters in hemodynamic phantom.

Methods: Patients with carotid stenosis were included in a prospective study. A realistic phantoms of carotid artery stenoses were 3D-printed based on CT angiography. Stenosis severity and hemodynamic flow parameters in the phantom evaluated using duplex sonography were correlated with CTA. The primary outcome was to compare the evaluation of the percentage of stenosis based on the measurement of diameter reduction and area reduction of the carotid artery among CTA, a 3D model constructed from CTA data, and ultrasound measurement of stenosis percentage within the 3D printed phantom. The secondary outcome was to determine whether the percentage of stenosis measured by ultrasound in B-mode or ultrasound-measured flow velocities (PSV, EDV) better correlates with the stenosis percentage derived from CTA and the phantom.

Results: The study included 95 subjects (average age 71 years, 75% male) with carotid stenosis, 39% were symptomatic. Significant correlations were found between ultrasound B-Mode findings on the phantom and CTA, with the strongest correlations for area reduction (Spearman r = 0.615, p < 0.0001) and diameter reduction (Spearman r = 0.465, p < 0.0001). The most robust correlation between PSV and EDV in stenosis and the percentage of stenosis was identified between PSV in stenosis and the percentage of stenosis by diameter reduction, as evaluated through ultrasound. The Spearman correlation coefficient revealed a relatively strong correlation, with a value of r = 0.444 (p < 0.0001), and the Kendall Tau correlation coefficient also demonstrated significance, with a value of r = 0.302 (p < 0.0001).

Conclusions: A significant correlation between CTA and duplex sonography measurements on the carotid phantom was demostrated, suggesting the potential utilization of the phantom in testing hemodynamic parameters of carotid stenosis.

The inequity of resources available for learning human anatomy, one of the basic sciences underpinning a medical or allied health training, between low- and high-income countries is stark. Many Low Middle-Income Countries (LMIC) have no access to cadavers for the study of human anatomy. In this review we try to highlight the status of anatomy education especially with regards to the barriers to accessing cadavers such as cost, local laws and regulations, religious beliefs and cultural mores. Many of these barriers are more acute in LMIC. We discuss possible solutions to the shortage of cadaver material and specifically we detail 3 case studies in which authors from high income countries can assist colleagues in LMIC institutions teach anatomy using 3D printed replicas of human dissections. The case for this assistance is made and its practical application together with its evaluation is presented. The case studies include medical schools in Liberia, Fiji and Papua New Guinea. The outcomes suggest this model could be expanded to other countries who lack the economic resources to adequately provide learning materials for undergraduate students in medicine and other allied health disciplines.

Background: Catheters used for magnetic resonance (MR)-guided interventions require intra-catheter coils and often produce artifacts. This study aimed to fabricate 3D-printed catheters impregnated with vitamin D solution to allow for optimal visualization during MR-guided procedures.

Methods: 3D printing was used to fabricate catheters impregnated with vitamin D solution. Computer-aided design files were generated for a size 18 French catheter prototype with a compartment for vitamin D solution to be manually introduced into the catheter's lumen and sealed via thermoplastic welding. Polylactic acid (PLA) bioplastic was 3D printed into filaments via material extrusion (FDM^®, Stratasys, Eden Prairie, MN) on a 5th generation Replicator 3D printer (MakerBot). Three different forms of vitamin D were used, cholecalciferol, ergocalciferol, and calcitriol, and 0.9% normal saline served as a control. Three prints of each catheter type were fabricated and scanned using a 1.5 T MR whole body scanner (Avanto, Siemens Healthcare) inside a small flex loop surface radiofrequency (RF) coil. A 3D gradient recalled echo (GRE) sequence was used with the following acquisition parameters: 4.52/11 ms TE/TR, 15° flip angle, 256 × 256 matrix with 0.5 mm × 0.5 mm in-plane resolution, 24 coronal slabs, 2 mm thickness, and 140 Hz receiver bandwidth. Three averages were used to improve the signal-to-noise ratio (SNR). The GRE sequence was run with 4 different flip angles: 3°, 15°, 30°, and 45° to perform T1 mapping.

Results: All 3D-printed catheters impregnated with vitamin D produced a signal on MR. SNR for vitamin D catheters was similar across the various forms of vitamin D: mean SNRs for 100% cholecalciferol, ergocalciferol, and calcitriol were 138, 139, and 130. Mean SNR and contrast-to-noise ratio (CNR) for vitamin D catheters were significantly higher than the control saline catheter (p < 0.001, for both SNR and CNR). T1 values were lower in vitamin D-impregnated catheters compared to the saline control (228 ± 67 ms and 3371 ± 493 ms, respectively; p < 0.0001), indicating a better signal.

Conclusions: 3D printing of catheters impregnated with vitamin D is feasible and can potentially optimize MR-guided procedures.

Object: 3D printing technology stands as a transformative force in medicine, offering outstanding precision and personalization in surgical planning, patient education, and the development of anatomical models for complex procedures. This paper aims to explore the application experiences of 3D printing in endoscopic skull base tumor surgeries, evaluating the impact and effectiveness of 3D-printed models in enhancing both surgical simulations and anatomical learning in the field of neurosurgery for skull base tumors.

Method: From October 2015 to March 2019, our institution enrolled five patients for whom individualized 3D-printed models were created, utilizing different printing techniques and materials. These models served a critical role in preoperatively determining the most effective surgical approaches. Additionally, they were instrumental in facilitating endoscopic surgery simulations and enhancing anatomical education. To assess the utility of these 3D models, nine neurosurgeons from our institution were surveyed using the Likert scale questionnaire, providing valuable insights into the effectiveness of 3D printing in clinical applications of neurosurgery.

Result: Our team successfully printed five complex skull base tumor models using 3D printing technology, which significantly improved the outcome of skull base tumor diagnosis and treatment. An evaluation of the Likert scores revealed that model 4, crafted using mixed photosensitive resin, was particularly effective for surgical simulation and anatomical education. The mean (standard deviation, SD) 3D printing time is 16.3 (5.54) hours, and the mean (SD) printing cost is 4,500 (1132.88) RMB, demonstrating the efficiency of this approach.

Conclusion: 3D printing technology emerges as a highly valuable asset in the realm of endoscopic surgery for skull base tumors. Its rapid production turnaround allows for urgent surgical preparation needs. Additionally, this technology optimizes the learning curve for clinical pathological anatomy and endoscopic surgery. This combination advances surgical practices and training, particularly in the challenging domain of skull base neurosurgery.

Background: The knowledge and understanding of the anatomy of lung segments is of great importance while segmentectomies are increasingly performed. To introduce new technologies and tools in anatomy teaching could help students to improve their skills.

Methods: Students participants (n = 16) were divided into 3 groups: traditional (n = 5), 3D visualization (n = 5) and 3D printing group (n = 6). Each student took a pre- and post-test exam. The traditional teaching group had lessons using 2D anatomical drawings, the 3D visualization group had lessons using a dedicated software allowing anatomical 3D reconstructions and the 3D printing group had lessons using 3D printed anatomical models.

Results: Students of the whole cohort had significant better scores at the post test (mean score = 14.2) compared to the pretest (mean score = 7.9) (p = 0.0011). In the traditional and 3D printing groups, students had significant better scores in the post-test (mean scores = 17.7 and 14.2 respectively) than in the pre-test (mean scores = 8.2 and 7.5; p = 0.0247 and p = 0.0003 respectively). There was no significant difference between the pre and post-test scores for the 3D visualization group (mean score = 8.2 and 11.7 respectively) (p = 0.4347).

Conclusions: The knowledge of lung segment anatomy is poor among our medical students. Both traditional and 3D-printed teaching was shown effective. The contribution of 3D printed models would probably improve anatomy teaching among medical students. The introduction of this technology is instinctive and easy to use for both students and teachers. Furthermore, this technique was not particularly expensive to set up.