Introduction: Bone fractures represent a global health problem with the incidence of fractures on the rise each year. The predominant method for addressing bone fractures involves immobilization. Worldwide, many initiatives have sought to develop innovative fracture immobilization designs, and numerous solutions have been patented. However, a comprehensive overview and systematic classification of these patented designs is lacking. Areas covered: In pursuit of these patented immobilization designs, the Espacenet database, recognized as the largest global repository of patents, served as the principal investigative tool. Using a search string, patent classifications and inclusion criteria a total of 71 patents were identified. These can be classified into four unique design groups: (1) fixed and partly enclosed, (2) fixed and fully enclosed, (3) adjustable and partly enclosed and (4) adjustable and fully enclosed designs. The designs that are commercially available are predominantly situated within groups 3 and 4. Expert opinion: Advances in 3D scanning and additive manufacturing could improve comfort, personalization, and monitoring in fracture immobilization, but clinical adoption is hindered by slow production times, workflow misalignment, and regulatory barriers. Key improvements are needed in scanning accuracy, adjustment protocols, and integration into hospital logistics to ensure both technical feasibility and clinical usability.

Introduction: Thromboembolic conditions are a leading global cause of mortality and a major cause of disability. Throughout the years mechanical thrombectomy has become a preferred method of treatment. Removing thrombus in its entirety on first pass decreases procedure time as well as lowers the risk of distal embolization. Areas covered: This review provides a comprehensive overview and classification of the patent literature on devices for non-fragmented thrombus removal via grip. Patentscope database was used to search for internationally granted patents published any time before the access date (October 2024). The search using keywords and patent classification code led to identifying 141 relevant patents that were then categorized based on location and type of grip they describe. Expert opinion: The designs found are analyzed in the discussion and a broader context for their relevance is given in the expert opinion section. The following review can provide insight into possible mechanical thrombectomy methods, general trends in the field as well as serve as an inspiration in development of novel devices.

Positioning a thin needle into a solid substrate near a target region is difficult because the needle can easily bend and buckle. Nevertheless, in nature, female parasitic wasps can do this by using buckling prevention and steering mechanisms. This study presents a self-propelled needle that incorporates wasp-inspired steering mechanisms, specifically, the use of pretension and asymmetry within the needle segments. The needle with an outer diameter of 0.89 millimeters comprises seven parallel needle segments, with the central needle segment being either straight for a forward trajectory or prebent for steering purposes. By retracting and rotating the prebent central needle segment, the needle is capable of omnidirectional steering. The performance of the needle in tissue-mimicking phantoms was evaluated in terms of its propulsion efficiency and steering performance. The propulsion efficiency, affected by slippage of the needle segments with respect to the tissue-mimicking phantoms, was, on average, 63% ± 4% for forward motion and 55% ± 7% for steering motion. Moreover, the needle successfully steered with a mean deflection-to-insertion ratio of 0.41 ± 0.11 (i.e., radius-of-curvature of 44 mm). The proposed bioinspired needle design is a relevant step toward developing steerable needles for percutaneous interventions.

Metal additive manufacturing is a promising technology for the production of functional medical products, due to its high shape complexity and resolution, and ability to withstand sterilization temperatures. This study explores the possibility of designing a completely non-assembly steerable surgical instrument using Selective Laser Melting. Despite its advantages for medical devices, the rough surface quality of unfinished parts can be problematic for non-assembly designs, leading to increased friction and wear in rigid body mechanisms and tendon-actuated mechanisms. We investigated printing of rolling contact joints with crossed flexures as low-friction joints, adjusted for printing in titanium for the design of the instrument. Grid-based lattice structures were incorporated as miniature flexures, and we explored the influence of various grid sizes on the flexibility and bending stiffness of the lattices. Based on this exploration, we altered the rolling joint configuration from two crossed flexures to a single straight flexure for our design. The resulting steerable surgical instrument design is completely non-assembly, including its actuation, facilitates easy removal of support structures, and requires no surface finishing steps. It has a diameter of less than 20 mm, facilitates opening and closing of a grasper, and steering of the grasper by 20 degrees.

While articulated surgical instruments have enabled the proliferation of minimally invasive interventions, procedures such as laparo-endoscopic single-site surgery are waning in popularity. One potential reason for this decline is a lack of sufficiently dexterous instruments. Although multi-steerable instruments exist, these are often complex and therefore expensive assemblies. Even when 3D printing was used to simplify the design of these instruments, the requirement for high-performance 3D printers limited the reduction in manufacturing costs. To tackle this issue, we propose six guidelines for converting a 3D printed compliant medical instrument from printing on a Digital Light Processing (DLP) printer to a Fused Filament Fabrication (FFF) printer. These guidelines provide a framework to manage and compensate for differences in the two processes to achieve comparable results at a reduced cost. The proposed guidelines were evaluated by assembling a FFF 3D printed prototype that shows equivalent performance to its DLP 3D printed counterpart.

Pipelines, vital for fluid transport, pose an important yet challenging inspection task, particularly in small, flexible biological systems, that robots have yet to master. In this study, we explored the development of an innovative robot inspired by the ovipositor of parasitic wasps to navigate and inspect pipelines. The robot features a flexible locomotion system that adapts to different tube sizes and shapes through a mechanical inflation technique. The flexible locomotion system employs a reciprocating motion, in which groups of three sliders extend and retract in a cyclic fashion. In a proof-of-principle experiment, the robot locomotion efficiency demonstrated positive linear correlation (r = 0.6434) with the diameter ratio (ratio of robot diameter to tube diameter). The robot showcased a remarkable ability to traverse tubes of different sizes, shapes and payloads with an average of (70%) locomotion efficiency across all testing conditions, at varying diameter ratios (0.7 1.5). Furthermore, the mechanical inflation mechanism displayed substantial load-carrying capacity, producing considerable holding force of (13 N), equivalent to carrying a payload of (≈5.8 Kg) inclusive the robot weight. This soft robotic system shows promise for inspection and navigation within tubular confined spaces, particularly in scenarios requiring adaptability to different tube shapes, sizes, and load-carrying capacities. The design of this system serves as a foundation for a new class of pipeline inspection robots that exhibit versatility across various pipeline environments, potentially including biological systems.

Introduction: This study focuses on the quantification of and current guidelines on the hazards related to needle positioning in prostate cancer treatment: (1) access restrictions to the prostate gland by the pubic arch, so-called Pubic Arch Interference (PAI) and (2) needle positioning errors. Next, we propose solution strategies to mitigate these hazards. Methods: The literature search was executed in the Embase, Medline ALL, Web of Science Core Collection*, and Cochrane Central Register of Controlled Trials databases. Results: The literature search resulted in 50 included articles. PAI was reported in patients with various prostate volumes. The level of reported PAI varied between 0 and 22.3 mm, depending on the patient’s position and the measuring method. Low-Dose-Rate Brachytherapy induced the largest reported misplacement errors, especially in the cranio-caudal direction (up to 10 mm) and the largest displacement errors were reported for High-Dose-Rate Brachytherapy in the cranio-caudal direction (up to 47 mm), generally increasing over time. Conclusions: Current clinical guidelines related to prostate volume, needle positioning accuracy, and maximum allowable PAI are ambiguous, and compliance in the clinical setting differs between institutions. Solutions, such as steerable needles, assist in mitigating the hazards and potentially allow the physician to proceed with the procedure. This systematic review was performed in accordance with the PRISMA guidelines. The review was registered at Protocols.io (DOI: dx.doi.org/10.17504/protocols.io.6qpvr89eplmk/v1).

Introduction: Bone biopsies have great value for the diagnosis of, amongst others, hematologic diseases. Although the bone biopsy procedure is mostly performed minimally invasive with the use of a slender cannula, the patient may still experience discomfort, especially when the procedure has to be repeated due to an unsuccessful biopsy. Areas covered: This review presents a comprehensive overview of bone biopsy devices presented in the patent literature. The patents were obtained using a classification search combined with keywords in the Espacenet patent database and were subsequently verified using pre-set eligibility criteria. This resulted in 62 unique patents included in this review. Expert opinion: The included patents were categorized based on the used strategies for the three steps that can be identified during a bone biopsy (1) biopsy sampling, (2) biopsy severing and (3) biopsy harvesting. Most patents described strategies for multiple steps. Insight into the used strategies and the comprehensive overview may serve as a source of inspiration for the design of novel bone biopsy devices.

Conventional medical instruments are not capable of passing through tortuous anatomy as required for natural orifice transluminal endoscopic surgery due to their rigid shaft designs. Nevertheless, developments in minimally invasive surgery are pushing medical devices to become more dexterous. Amongst devices with controllable flexibility, so-called Follow-The-Leader (FTL) devices possess motion capabilities to pass through confined spaces without interacting with anatomical structures. The goal of this literature study is to provide a comprehensive overview of medical devices with FTL motion. A scientific and patent literature search was performed in five databases (Scopus, PubMed, Web of Science, IEEExplore, Espacenet). Keywords were used to isolate FTL behavior in devices with medical applications. Ultimately, 35 unique devices were reviewed and categorized. Devices were allocated according to their design strategies to obtain the three fundamental sub-functions of FTL motion: steering, (controlling the leader/end-effector orientation), propagation, (advancing the device along a specific path), and conservation (memorizing the shape of the path taken by the device). A comparative analysis of the devices was carried out, showing the commonly used design choices for each sub-function and the different combinations. The advantages and disadvantages of the design aspects and an overview of their performance were provided. Devices that were initially assessed as ineligible were considered in a possible medical context or presented with FTL potential, broadening the classification. This review could aid in the development of a new generation of FTL devices by providing a comprehensive overview of the current solutions and stimulating the search for new ones.

Magnetostrictive strain sensors with high spinorbit coupling have been integrated with Fiber-Bragg-Grating sensors wherein the gap within the gratings varies with strain within the encapsulating magnetostrictive material. Terfenol-D has been chosen as the mm sized magnetostrictive material which exhibits the largest known bulk magnetostriction. The setup utilised consists of an optical to electrical transducer leading to lower noise in the system while carrying out sensing in the magneto-optic domain. Non-linear isotropic analytical modeling and linear anisotropic finite element modeling is carried out to gain further insight into the variation of material parameters with external magnetic field intensity. The operated magnetic fields lie within 100 µT with a sensor sensitivity of 0.6 kHz/ppm, thus reducing risks due to any prolonged or repeated exposure. This technology can be integrated with state-of-the-art sensors with high sensitivity to create smaller and safer tracking systems, particularly in-vivo.