Insertion mechanics of bioinspired needles into soft tissues

Design of composite puncture blood collection system and research on puncture force

Venous blood collection testing is one of the most commonly used medical diagnostic methods. Compared with conventional venous blood collection, robotic collection can reduce needle-stick injuries, medical staff workload, and infection risk; allow doctor-patient isolation; and improve collection reliability. Existing venous blood collection robots use rigid puncture needles, which can easily puncture the lower wall of blood vessels, causing vessel damage and collection failure. This paper proposes a bionic blood collection strategy based on a composite puncture needle that mimics the structure and function of mosquito mouthparts. A bionic composite puncture needle insertion system with puncture-force sensing was designed, and venipuncture forces were simulated and mathematically modelled. A prototype insertion system was built and used in an experiment, which demonstrated effective composite puncture blood collection and explored the factors influencing puncture force. Puncture force decreases with increased puncture speed and angle and with a decreased needle diameter. This provides a basis for optimising the parameters of blood collection robots.

Honeybee stinger-based biopsy needle and influence of the barbs on needle forces during insertion/extraction into the iliac crest: A multilayer finite element approach

Bone marrow biopsy (BMB) needles are frequently used in medical procedures, including extracting biological tissue to identify specific lesions or abnormalities discovered during a medical examination or a radiological scan. The forces applied by the needle during the cutting operation significantly impact the sample quality. Excessive needle insertion force and possible deflection might cause tissue damage, compromising the integrity of the biopsy specimen. The present study aims at proposing a revolutionary bioinspired needle design that will be utilized during the BMB procedure. A non-linear finite element method (FEM) has been used to analyze the insertion/extraction mechanisms of the honeybee-inspired biopsy needle with barbs into/from the human skin-bone domain (i.e., iliac crest model). It can be seen from the results of the FEM analysis that stresses are concentrated around the bioinspired biopsy needle tip and barbs during the needle insertion process. Also, these needles reduce the insertion force and reduce the tip deflection. The insertion force in the current study has been reduced by 8.6% for bone tissue and 22.66% for skin tissue layers. Similarly, the extraction force has been reduced by an average of 57.54%. Additionally, it has been observed that the needle-tip deflection got reduced from 10.44 mm for a plain bevel needle to 6.3 mm for a barbed biopsy bevel needle. According to the research findings, the proposed bioinspired barbed biopsy needle design could be utilized to create and produce novel biopsy needles for successful and minimally invasive piercing operations.

Bioinspired medical needles: a review of the scientific literature

Needles are commonly used in medical procedures. However, current needle designs have some disadvantages. Therefore, a new generation of hypodermic needles and microneedle patches drawing inspiration from mechanisms found in nature (i.e. bioinspiration) is being developed. In this systematic review, 80 articles were retrieved from Scopus, Web of Science, and PubMed and classified based on the strategies for needle-tissue interaction and propulsion of the needle. The needle-tissue interaction was modified to reduce grip for smooth needle insertion or enlarge grip to resist needle retraction. The reduction of grip can be achieved passively through form modification and actively through translation and rotation of the needle. To enlarge grip, interlocking with the tissue, sucking the tissue, and adhering to the tissue were identified as strategies. Needle propelling was modified to ensure stable needle insertion, either through external (i.e. applied to the prepuncturing movement of the needle) or internal (i.e. applied to the postpuncturing movement of the needle) strategies. External strategies include free-hand and guided needle insertion, while friction manipulation of the tissue was found to be an internal strategy. Most needles appear to be using friction reduction strategies and are inserted using a free-hand technique. Furthermore, most needle designs were inspired by insects, specifically parasitoid wasps, honeybees, and mosquitoes. The presented overview and description of the different bioinspired interaction and propulsion strategies provide insight into the current state of bioinspired needles and offer opportunities for medical instrument designers to create a new generation of bioinspired needles.

Experimental study of mosquito-inspired needle to minimize insertion force and tissue deformation

The aim of this work is to propose a mosquito-inspired (bioinspired) design of a surgical needle that can decrease the insertion force and the tissue deformation, which are the main causes of target inaccuracy during percutaneous procedures. The bioinspired needle was developed by mimicking the geometrical shapes of mosquito proboscis. Needle prototypes were manufactured and tested to determine optimized needle shapes and geometries. Needle insertion tests on a tissue-mimicking polyvinylchloride (PVC) gel were then performed to emulate the mosquito-proboscis stinging dynamics by applying vibration and insertion velocity during the insertion. An insertion test setup equipped with a sensing system was constructed to measure the insertion force and to assess the deformation of the tissue. It was discovered that using the proposed bioinspired design, the needle insertion force was decreased by 60% and the tissue deformation was reduced by 48%. This finding is significant for improving needle-based medical procedures.

Cone cracks in tissue-mimicking hydrogels during hypodermic needle insertion: the role of water content

Needle insertion into soft biological tissues is a common process in various surgical procedures. During insertion, soft biological tissues with different water contents undergo large deformation often leading to uncontrollable cracks and tissue damage. Despite the numerous experimental studies and numerical modelling of needle-tissue interaction, the results do not show any consistency mainly due to the heterogeneity of tissue properties and opaqueness. In this context, understanding the fracture behaviour of soft tissues during needle insertion is important for minimally invasive surgeries and other medical procedures. Recently, we showed that the needle insertion into a transparent, tissue-mimicking polyacrylamide (PAAm) hydrogel causes periodic cone cracks. In this work, we systematically varied the water content of the PAAm hydrogel in the preparation state and performed needle insertion experiments using a hypodermic needle at a constant velocity to study the fracture characteristics of the PAAm hydrogel. The results show that the number of peaks, the magnitudes of the insertion forces, and corresponding cone cracks decrease with increasing water content. Furthermore, we discussed the influence of water on cone crack fracture characteristics, cone angle, periodicity, crack speed and fracture energy release rate. These results provide a better understanding of the fracture processes of soft tissues with different water concentrations such as the lung, liver, and brain during needle insertion and the control of tissue damage during needle insertion involved in medical procedures.

Needle insertion-induced quasiperiodic cone cracks in hydrogel

Needle insertion, a standard process for various minimally invasive surgeries, results in tissue damage which sometimes leads to catastrophic outcomes. Opaqueness and inhomogeneity of the tissues make it difficult to observe the underlying damage mechanisms. In this paper, we use transparent and homogeneous polyacrylamide hydrogel as a tissue mimic to investigate the damages caused during needle insertion. The insertion force shows multiple events, characterised by a gradual increase in the force followed by a sharp fall. Synchronised recording of the needle displacement into the gel shows that each event corresponds to propagation of stable cone crack. Though sporadic uncontrolled cracking has been discussed earlier, this is the first report of nearly periodic, stable and well-controlled 3-D cone cracks inside the hydrogel during deep penetration. We show that the stress field around the needle tip is responsible for the symmetry and periodicity of the cone cracks. These results provide a better understanding of the fracture processes in soft and brittle materials and open a promising perspective in needle designs and the control of tissue damages during surgical operations.

Experimental study of the optimum puncture pattern of robot-assisted needle insertion into hyperelastic materials

The robot-assisted insertion surgery plays a crucial role in biopsy and therapy. This study focuses on determining the optimum puncture pattern for robot-assisted insertion, aiming at the matching problem of needle insertion parameters, thereby to reduce the pain for patients and to improve the reachability to the lesion point. First, a 6-degrees of freedom (DOFs) Computed Tomography (CT)-guided surgical robotic system for minimally invasive percutaneous lung is developed and used to perform puncture experiments. The effects of four main insertion factors on the robotic puncture are verified by designing the orthogonal test, where the inserting object is the artificial skin-like specimen with high transparent property and a digital image processing method is used to analyze the needle tip deflection. Next, the various phases of puncture process are divided and analyzed in detail in view of the tissue deformation and puncture force. Then, short discussion on the comparison of puncture force with different effect factors for the same beveled needle is presented. The same pattern can be observed for all of the cases. Finally, based on the experimental data, the formulations of the puncture force and needle deflection which depends on Gauge size, insertion velocity, insertion angle, and insertion depth are developed using the multiple regression method, which can be used to get an optimum puncture pattern under the constrains of minimum peak force and minimum needle tip deflection. The developed models have the effectiveness and applicability on determining the optimum puncture pattern for one puncture event, and which can also provide insights useful for the setting of insertion parameters in clinical practice.

Mosquito proboscis-inspired needle insertion to reduce tissue deformation and organ displacement

This study investigates mosquito proboscis-inspired (MPI) insertion applied to the clinically used biopsy needle to reduce tissue deformation and organ displacement. Advanced medical imagining has enabled early-stage identification of cancerous lesions that require needle biopsy for minimally invasive tissue sampling and pathological analysis. Accurate cancer diagnosis depends on the accuracy of needle deployment to the targeted cancerous lesion site. However, currently available needle delivery systems deform and move soft tissue and organs, leading to a non-diagnostic biopsy or undersampling of the target. Two features inspired by the mosquito proboscis were adopted for MPI insertion in prostate biopsy: (1) the harpoon-shape notches at the needle tip and (2) reciprocating needle-cannula motions for incremental insertion. The local tissue deformation and global prostate displacement during the MPI vs. traditional direct insertions were quantified by optically tracking the displacement of particle-embedded tissue-mimicking phantoms. Results show that the MPI needle insertion reduced both local tissue deformation and global prostate displacement because of the opposite needle-cannula motions and notches which stabilized and reduced the tissue deformation during insertion. Findings provide proof of concept for MPI insertion in the clinical biopsy procedures as well as insights of needle–tissue interaction for future biopsy technology development.

Effect of vibration on insertion force and deflection of bioinspired needle in tissues

The design of surgical needles used in biopsy procedures have remained fairly standard despite the increase in complexity of surgeries. Higher needle insertion forces and deflection can increase tissue damage and decrease biopsy sample integrity. To overcome these drawbacks, we present a novel bioinspired approach to reduce insertion forces and minimize needle-tip deflection. It is well known from the literature, design of bioinspired surgical needles results in decreasing insertion forces and needle-tip deflection from the needle insertion path. This technical note studies the influence of vibration on bioinspired needle to further reduce insertion forces and needle-tip deflection. Bioinspired needle geometrical parameters such as barb shapes and geometries were analyzed to determine the best design parameters. Static and dynamic (vibration) needle insertion tests were performed to determine the maximum insertion forces and to estimate needle-tip deflection. Our results show that introducing vibration on the bioinspired needle insertion can reduce the maximum insertion force by up to 50%. It was also found that the needle-tip deflection is decreased by 47%.

Tissue Deformation and Insertion Force of Bee-Stinger Inspired Surgical Needles

Surgical needles are commonly used to reach target locations inside of the body for percutaneous procedures. The major issues in needle steering in tissues are the insertion force which causes tissue damage and tissue deformation that causes the needle path deviation (i.e., tip deflection) resulting in the needle missing the intended target. In this study, honeybee-inspired needle prototypes were proposed and studied to decrease the insertion force and to reduce the tissue deformation. Three-dimensional (3D) printing technology was used to manufacture scaled-up needle prototypes. Needle insertion tests on tissue-mimicking polyvinyl chloride (PVC) gel were performed to measure the insertion force and the tip deflection. Digital image correlation (DIC) study was conducted to determine the tissue deformation during the insertion. It was demonstrated that the bioinspired needles can be utilized to decrease the insertion force by 24% and to minimize the tip deflection. It was also observed that the bioinspired needles decrease the tissue deformation by 17%. From this study, it can be concluded that the proposed bee-inspired needle design can be used to develop and manufacture innovative surgical needles for more effective and less invasive percutaneous procedures.

Novel design of honeybee-inspired needles for percutaneous procedure

The focus of this paper is to present new designs of innovative bioinspired needles to be used during percutaneous procedures. Insect stingers have been known to easily penetrate soft tissues. Bioinspired needles mimicking the barbs in a honeybee stinger were developed for a smaller insertion force, which can provide a less invasive procedure. Decreasing the insertion force will decrease the tissue deformation, which is essential for more accurate targeting. In this study, some design parameters, in particular, barb shape and geometry (i.e. front angle, back angle, and height) were defined, and their effects on the insertion force were investigated. Three-dimensional printing technology was used to manufacture bioinspired needles. A specially-designed insertion test setup using tissue mimicking polyvinyl chloride (PVC) gels was developed to measure the insertion and extraction forces. The barb design parameters were then experimentally modified through detailed experimental procedures to further reduce the insertion force. Different scales of the barbed needles were designed and used to explore the size-scale effect on the insertion force. To further investigate the efficacy of the proposed needle design in real surgeries, preliminary ex vivo insertion tests into bovine liver tissue were performed. Our results show that the insertion force of the needles in different scales decreased by 21-35% in PVC gel insertion tests, and by 46% in bovine liver tissue insertion tests.