Recent advancements in medical imaging, virtual surgical planning (VSP), and three-dimensional (3D) printing have potentially changed how today’s craniomaxillofacial surgeons use patient information for customized treatments. Over the years, polyetheretherketone (PEEK) has emerged as the biomaterial of choice to reconstruct craniofacial defects. With advancements in additive manufacturing (AM) systems, prospects for the point-of-care (POC) 3D printing of PEEK patient-specific implants (PSIs) have emerged. Consequently, investigating the clinical reliability of POC-manufactured PEEK implants has become a necessary endeavor. Therefore, this paper aims to provide a quantitative assessment of POC-manufactured, 3D-printed PEEK PSIs for cranial reconstruction through characterization of the geometrical, morphological, and biomechanical aspects of the in-hospital 3D-printed PEEK cranial implants. The study results revealed that the printed customized cranial implants had high dimensional accuracy and repeatability, displaying clinically acceptable morphologic similarity concerning fit and contours continuity. From a biomechanical standpoint, it was noticed that the tested implants had variable peak load values with discrete fracture patterns and failed at a mean (SD) peak load of 798.38 ± 211.45 N. In conclusion, the results of this preclinical study are in line with cranial implant expectations; however, specific attributes have scope for further improvements.

Additive manufacturing (AM) of polyetheretherketone (PEEK) biomaterials using the material-extrusion (MEX) method has been studied for years. Because of the challenging manufacturing process, precisely controlling printing parameters is crucial. This study aimed to investigate the effects of printing parameters such as orientation and position of printing on mechanical properties. Thus, 34 samples were printed using PEEK filament and the MEX process. Samples were divided into two main groups (A,B) according to their printing orientations (A: groups 1–3) and positions on the build plate (B: groups 4–8). Mechanical tensile tests were performed to evaluate the effects of different printing orientations and positions on mechanical properties. The means of the tensile modulus in samples 3D-printed in XY (group 1), XZ (group 2), and ZX (group 3) orientations were not significantly different (p-value = 0.063). Groups 1 and 2 had smaller distributions than group 3 in the means of tensile strength. The t-test showed that the overall means of the measurements in groups 4–8 did not differ significantly (p-value = 0.315). The tensile tests indicated that printing in vertical and horizontal orientations had no significant influence on mechanical properties. There were no significant differences in mechanical strength between top/bottom printed samples in five different lateral positions. Reliability of printing with good mechanical properties could be a step forward to manufacturing patient-specific implants.

Purpose: The use of computer-assisted virtual surgical planning (VSP) for craniosynostosis surgery is gaining increasing implementation in the clinics. However, accurately transferring the preoperative planning data to the operating room remains challenging. We introduced and investigated a fully digital workflow to perform fronto-orbital advancement (FOA) surgery using 3D-printed patient-specific implants (PSIs) and cold-ablation robot-guided laser osteotomy. This novel approach eliminates the need for traditional surgical templates while enhancing precision and customization, offering a more streamlined and efficient surgical process. Methods: Computed tomography data of a patient with craniosynostosis were used to digitally reconstruct the skull and to perform VSP of the FOA. In total, six PSIs per skull were 3D-printed with a medical-grade bioresorbable composite using the Arburg Plastic Freeforming technology. The planned osteotomy paths and the screw holes, including their positions and axis angles, were digitally transferred to the cold-ablation robot-guided osteotome interface. The osteotomies were performed on 3D-printed patient skull models. The implants, osteotomy and final FOA results were scanned and compared to the VSP data. Results: The osteotomy deviations for the skulls indicated an overall maximum distance of 1.7 mm, a median deviation of 0.44 mm, and a maximum root mean square (RMS) error of 0.67 mm. The deviation of the point-to-point surface comparison of the FOA with the VSP data resulted in a median accuracy of 1.27 mm. Accessing the orbital cavity with the laser remained challenging. Conclusion: This in vitro study showcases a novel FOA technique by effectively combining robot-guided laser osteotomy with 3D-printed patient-specific implants, eliminating the need for surgical templates and achieving high accuracy in bone cutting and positioning. The workflow holds promise for reducing preoperative planning time and increasing surgical efficiency. Further studies on bone tissue are required to validate the safety and effectiveness of this approach, especially in addressing the challenges of pediatric craniofacial surgery.

Introduction: Energy modulators (EM) have gained increasing attention due to their relevance in FLASH proton therapy. Current EM designs are fragile, necessitating thin ridges and limited sizes. Production requires advanced and costly 3D printers, as basic filament printers are inadequate, leading to expensive outsourcing. We propose an innovative EM design to address these limitations. Methods: The novel design consists of boxes stacked one on top of the other. Each box is created with two distinct infillratios: one for the inner cube and one for the larger cube surrounding it. The size of the inner and outer cubes is optimized along with the infill ratio. This structure is repeated periodically for box-like targets or varied to achieve the desired dose distribution.We design, slice, and print the EM using a Bambu Lab-X1C filament printer and polylactic acid filament. The simulation was performed using a GPU-based Monte Carlo simulation (FRED), where the EM was modeled as a combination of cubes with variable heights, with the infill ratio mapped to the material height. The simulation design was validated through depth-dose curve measurements using PSI Gantry 2. Results: EM for box-like targets of 35mm depth were designed and manufactured by varying the infill ratio between 30% and 100%. We chose cubic infill for isotropic periodicity, ensuring that impinging particles encounter uniform material distribution. Manufacturing constraints require 100% (concentric) infill in areas smaller than 1.5mm2. The simulations were validated by depth dose curve measurements with shape and distal range agreement to within detector uncertainties (<1mm). Conclusion: We realized a 3D-printed EM that is easier to produce and more resistant to physical damage than current alternatives. This design demonstrates the potential for a costeffective, easily manufacturable, and scalable EM.