Investigation of the effectiveness of prehospital amputation devices on cadavers.

Amputations take place in the operating rooms. At dangerous sites, circumstances may necessitate on-site amputation to save lives. Currently, there are no evidence-based guidelines for the execution of the amputation or the instruments to be chosen. Furthermore, there are no widely accepted criteria for the standardized characterization of amputation devices. The present study examined the effectiveness of commercially available cutting tools and instruments used by rescue services as possible on-site amputation tools. Five different tools (Holmatro type hydraulic cutter, with two cutting attachments, reciprocating saw, hacksaw, Gigli saw) were used to carry out amputations on designated locations on cadavers (brachial, antebrachial, femoral, and crural regions). During the experiment, the time required for amputation and the number of necessary cutting attempts to detach limbs were recorded. The proximal cut surfaces were analyzed with the help of post-amputation CT scan-based 3D models. An Amputation Index (AI) was determined for each device in each examined region based on the cut surface quality. An Amputation Score (AS) was calculated using the time required for cutting, the number of cutting attempts, and the AI. With the help of AS, the usability of the used devices was determined. According to our scoring system, the reciprocating saw proved the most effective tool. Based on our results, we recommend the consideration and further investigation of the reciprocating saw as a possible on-site amputation device, as well as the introduction of the Amputation Score as an objective and quantitative indicator in the future characterization of on-site amputation devices.

Manufacturing a First Upper Molar Dental Forceps Using Continuous Fiber Reinforcement (CFR) Additive Manufacturing Technology with Carbon-Reinforced Polyamide.

3D printing is an emerging and disruptive technology, supporting the field of medicine over the past decades. In the recent years, the use of additive manufacturing (AM) has had a strong impact on everyday dental applications. Despite remarkable previous results from interdisciplinary research teams, there is no evidence or recommendation about the proper fabrication of handheld medical devices using desktop 3D printers. The aim of this study was to critically examine and compare the mechanical behavior of materials printed with FFF (fused filament fabrication) and CFR (continuous fiber reinforcement) additive manufacturing technologies, and to create and evaluate a massive and practically usable right upper molar forceps. Flexural and torsion fatigue tests, as well as Shore D measurements, were performed. The tensile strength was also measured in the case of the composite material. The flexural tests revealed the measured force values to have a linear correlation with the bending between the 10 mm (17.06 N at 5000th cycle) and 30 mm (37.99 N at 5000th cycle) deflection range. The findings were supported by scanning electron microscopy (SEM) images. Based on the results of the mechanical and structural tests, a dental forceps was designed, 3D printed using CFR technology, and validated by five dentists using a Likert scale. In addition, the vertical force of extraction was measured using a unique molar tooth model, where the reference test was carried out using a standard metal right upper molar forceps. Surprisingly, the tests revealed there to be no significant differences between the standard (84.80 N ± 16.96 N) and 3D-printed devices (70.30 N ± 4.41 N) in terms of extraction force in the tested range. The results also highlighted that desktop CFR technology is potentially suitable for the production of handheld medical devices that have to withstand high forces and perform load-bearing functions.