Study of Tissue Damage Induced by Insertion of Composite-Coated Needle.

Medical interventions have significantly progressed in developing minimally invasive techniques like percutaneous procedures. These procedures include biopsy and internal radiation therapy, where a needle or needle-like medical device is inserted through the skin to access a target inside the body. Ensuring accurate needle insertion and minimizing tissue-damage or cracks are critical in these procedures. This research aims to examine the coated needle effect on the force required to insert the needle (i.e., insertion force) and on tissue-damage during needle insertion into the bovine kidney. Reducing the needle insertion force, which is influenced by needle surface friction, generally results in a reduction in tissue-damage. Surgical needles were coated with a composite material, combining Polytetrafluoroethylene, Polydopamine, and Activated Carbon. Force measurement during needle insertion and a histological study to determine tissue-damage were conducted to evaluate the effectiveness of the coating. The insertion force was reduced by 49 % in the case of the coated needles. Furthermore, a histological analysis comparing tissue-damage resulting from coated and uncoated needles revealed an average 39 % reduction in tissue-damage with the use of coated needles. The results of this study demonstrate the potential of coated needles to enhance needle insertion and safety during percutaneous procedures.

An experimental study on the mechanics and control of SMA-actuated bioinspired needle.

Active needles demonstrate improved accuracy and tip deflection compared to their passive needle counterparts, a crucial advantage in percutaneous procedures. However, the ability of these needles to effectively navigate through tissues is governed by needle-tissue interaction, which depends on the tip shape, the cannula surface geometry, and the needle insertion method. In this research, we evaluated the effect of cannula surface modifications and the application of a vibrational insertion technique on the performance of shape memory alloy (SMA)-actuated active needles. These features were inspired by the mosquito proboscis' unique design and skin-piercing technique that decreased the needle tissue interaction force, thus enhancing tip deflection and steering accuracy. The bioinspired features, i.e., mosquito-inspired cannula design and vibrational insertion method, in an active needle reduced the insertion force by 26.24% and increased the tip deflection by 37.11% in prostate-mimicking gel. In addition, trajectory tracking error was reduced by 48%, and control effort was reduced by 23.25%, pointing towards improved needle placement accuracy. The research highlights the promising potential of bioinspired SMA-actuated active needles. Better tracking control and increased tip deflection are anticipated, potentially leading to improved patient outcomes and minimized risk of complications during percutaneous procedures.

A study on modeling the deflection of surgical needle during insertion into multilayer tissues.

The use of subcutaneous and percutaneous needle and catheter insertions is standard in modern clinical practice. However, a common issue with bevel tip surgical needles is their tendency to deflect, causing them to miss the intended target inside the tissue. This study aims to understand the interaction between the needle and soft tissue and develop a model to predict the deflection of a bevel tip needle during insertion into multi-layered soft tissues. The study examined the mechanics of needle-tissue interaction and modeled the forces involved during insertion. The force model includes cutting force, deformation force, and friction between the needle and tissue. There was an 8%-23% difference between the total analytical and experimental force measurements. A modified Euler-Bernoulli beam elastic foundation theory was used to create an analytical model to predict the needle tip deflection in soft tissue. To validate the results, the analytical deflection model was then compared to the deflection from needle insertion experiments on multi-layered phantom tissues, showing a 9%-21% error between the two. While there is a slight discrepancy between the analytical and experimental results, the study shows that the proposed model can accurately predict needle tip deflection during insertion.

Experimental and analytical study on insertion force of composite-coated needle in soft tissue material.

Medical interventions require control over surgical needle insertion to minimize tissue damage and target inaccuracies during percutaneous procedures. The composite coating of the needle using Polydopamine (PDA), Polytetrafluoroethylene (PTFE), and Activated Carbon (C) has been used to reduce the damaging needle insertion force. This research aims to further understand the interfacial mechanics of coated needle insertion by studying the forces at the needle and tissue interface and developing an analytical insertion force model through a combined experimental and numerical method. The proposed analytical force model is divided into two components: (1) Friction force on the needle shaft, modeled using a modified Karnopp model that includes an elastic force component; (2) Cutting force on the needle tip, modeled using a constant cutting coefficient for a given tissue and insertion speed. In this work, the analytical model was established by incorporating experiments conducted at a reasonable 35 mm insertion depth in tissues. In a bovine kidney with a 35 mm insertion depth, the insertion force evaluated through experimentation and modeling differed by 6.5% for a bare needle and 17.1% for a coated needle. It is important to note that this difference in the analytical insertion force model is anticipated when dealing with real tissues with a highly complex structured tissue. Prediction of the insertion force could potentially be utilized in robotic needle systems for needle control to improve the success of percutaneous procedures.

Design and evaluation of shape memory alloy-actuated active needle using finite element analysis and deflection tracking control in soft tissues.

BACKGROUND: Conventional needles lack active mechanisms for large tip deflection to bypass obstacles or guide through a desired trajectory in needle-based procedures, compromising accuracy and effectiveness. METHODS: An active needle with a shape memory alloy (SMA) actuator was designed and evaluated by demonstrating deflections in tissue-mimicking gels. Finite element simulation and real-time needle tip deflection tracking in tissue-mimicking gels were performed. RESULTS: The active needle deflected 50 and 39 mm at 150 mm insertion depth in the liver and prostate mimicking gels, respectively. Reasonable simulation errors of 16.42% and 12.62% in needle deflections and small root mean squared errors of 1.42 and 1.47 mm in deflection tracking were obtained. CONCLUSIONS: The proposed needle produced desirable large tip deflections capable of bypassing obstacles in the insertion path and tracked a preplanned trajectory with minor errors. The finite element study would help optimise needle designs and predict deflections in soft tissues.

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.

Assessment of tissue damage from mosquito-inspired surgical needle.

INTRODUCTION: Many percutaneous procedures utilize surgical needles to extract tissue samples in biopsy or to apply specific cancer treatments. A design of mosquito-inspired surgical needles was proposed to improve the efficacy of these procedures by reducing the needle insertion force and the resulting tissue damage. The focus of this study is to assess tissue damage caused by the insertion of a mosquito-inspired needle into soft tissues. MATERIAL AND METHODS: In this work, the geometric features and the dynamic stinging (insertion) mechanism of mosquito proboscis were mimicked for the design of 3D-manufactured bioinspired needle prototypes. A specially designed test setup was developed to measure the insertion force in bovine liver tissue. The histology assessment based on hematoxylin and eosin staining and image analysis was conducted to determine the bovine liver tissue damage. RESULTS: It was observed that the insertion force can be reduced by up to 39% and the bovine liver tissue damage was decreased by 27% using the mosquito-inspired needles when compared with using the standard needles. CONCLUSION: The findings from this study suggested that the bioinspired needle design has great potential to advance surgical needles for more effective and less invasive percutaneous procedures.

Effect of composite coating on insertion mechanics of needle structure in soft materials.

This research aims to study the effect of a composite coating comprised of polydopamine (PDA), polytetrafluoroethylene (PTFE), and activated Carbon on the insertion mechanics of surgical needles in tissues i.e., polyvinyl chloride (PVC) tissue phantom and bovine kidney. A needle insertion and extraction test system was designed and constructed to measure the insertion and extraction forces. It was found that the composite coating on the needle surface decreases the maximum average insertion and extraction forces by 62% and 64%, respectively, when tested in PVC tissue phantom and by 49% and 30%, respectively, in bovine kidney tissue. Additionally, an Atomic Force Microscope study was performed to characterize the surface properties of the coated needles. It was found that the composite coating reduced the friction force on the needle surface by 65.7%. The decrease in these forces is critical in minimizing tissue damage and decreasing needle path deviation or deflection during percutaneous procedures.

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%.

Insertion mechanics of bioinspired needles into soft tissues.

INTRODUCTION: Most studies to date confirm that any increase in the needle insertion force increases the damage to the tissue. When it comes to brain tissue, even minor damage can cause a long-lasting traumatic brain injury. Thus there is a great demand for innovative minimally invasive needles among the medical community. In our previous studies a novel bioinspired needle design with specially designed barbs was used to perform insertion tests into Polyvinyl chloride (PVC) tissue-mimicking gels, in which it decreased the insertion force by as much as 25%. MATERIAL AND METHODS: In this work, bioinspired needles were designed using a CAD software, and were then manufactured using a 3 D printer. The insertion tests into bovine brain and liver were then performed to further investigate the performance of our bioinspired needles in real tissues. RESULTS: Our results show that there was a 10-25% decrease in the insertion force for insertions into bovine brain, and a 35-45% reduction in the insertion force for insertions into bovine liver using the proposed bioinspired needles. CONCLUSION: The reduction in the insertion force is due to the decrease in the friction force of the bioinspired needle with the bovine tissues, and its results are consistent with our previous results.

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.

Simulation and experimental studies in needle-tissue interactions.

This work aims to introduce a new needle insertion simulation to predict the deflection of a bevel-tip needle inside soft tissue. The development of such a model, which predicts the steering behavior of the needle during needle-tissue interactions, could improve the performance of many percutaneous needle-based procedures such as brachytherapy and thermal ablation, by means of the virtual path planning and training systems of the needle toward the target and thus reducing possible incidents of complications in clinical practices. The Arbitrary-Lagrangian-Eulerian (ALE) formulation in LS-DYNA software was used to model the solid-fluid interactions between the needle and tissue. Since both large deformation and fracture of the continuum need to be considered in this model, applying ALE method for fluid analysis was considered a suitable approach. A 150 mm long needle was used to bend within the tissue due to the interacting forces on its asymmetric bevel tip. Three experimental cases of needle steering in a soft phantom were performed to validate the simulation. An error measurement of less than 10 % was found between the predicted deflection by the simulations and the one observed in experiments, validating our approach with reasonable accuracy. The effect of the needle diameter and its bevel tip angle on the final shape of the needle was investigated using this model. To maneuver around the anatomical obstacles of the human body and reach the target location, thin sharp needles are recommended, as they would create a smaller radius of curvature. The insertion model presented in this work is intended to be used as a base structure for path planning and training purposes for future studies.

Design optimization study of a shape memory alloy active needle for biomedical applications.

Majority of cancer interventions today are performed percutaneously using needle-based procedures, i.e. through the skin and soft tissue. The difficulty in most of these procedures is to attain a precise navigation through tissue reaching target locations. To overcome this challenge, active needles have been proposed recently where actuation forces from shape memory alloys (SMAs) are utilized to assist the maneuverability and accuracy of surgical needles. In the first part of this study, actuation capability of SMA wires was studied. The complex response of SMAs was investigated via a MATLAB implementation of the Brinson model and verified via experimental tests. The isothermal stress-strain curves of SMAs were simulated and defined as a material model in finite element analysis (FEA). The FEA was validated experimentally with developed prototypes. In the second part of this study, the active needle design was optimized using genetic algorithm aiming its maximum flexibility. Design parameters influencing the steerability include the needle's diameter, wire diameter, pre-strain and its offset from the needle. A simplified model was presented to decrease the computation time in iterative analyses. Integration of the SMA characteristics with the automated optimization schemes described in this study led to an improved design of the active needle.

Development of a coordinated controller for robot-assisted shape memory alloy actuated needle for prostate brachytherapy.

This paper deals with the development of a coordinated control system for a robot and robot-driven shape memory alloy (SMA) actuated needle to follow a curvilinear path for percutaneous intervention. The robot driving the needle is considered as the outer loop and the non-linear SMA actuated flexible needle system forms the inner loop. The two feedback control loops are coordinated in such a way that the robot drives the needle considering the needle's actual deflection so that the needle tip reaches the target location with an acceptable accuracy. Simulation results are presented to verify the efficacy of the controller for tracking the overall desired trajectory which includes the combined trajectory of the robot and the needle.

Path planning for robot-assisted active flexible needle using improved Rapidly-Exploring Random trees.

In robot-assisted needle-based medical procedures, path planning for a flexible needle is challenging with regard to time consumption and searching robustness for the solution due to the nonholonomic motion of the needle tip and the presence of anatomic obstacles and sensitive organs in the intended needle path. We propose a novel and fast path planning algorithm for a robot-assisted active flexible needle. The algorithm is based on Rapidly-Exploring Random Trees combined with reachability-guided strategy and greedy heuristic strategy. Linear segments are taken into consideration to the paths, and insertion orientations are relaxed by the introduction of the linear segments. The proposed algorithm yields superior results as compared to the commonly used algorithm in terms of computational speed, form of path and robustness of searching ability, which potentially can make it suitable for the real-time intraoperative planning for clinical procedures.

Polyacrylamide phantom for self-actuating needle-tissue interaction studies.

This study presents a polyacrylamide gel as a phantom material for needle insertion studies specifically developed for self-actuating needles to enhance the precise placement of needles in prostate. Bending of these self-actuating needles within tissue is achieved by Nitinol actuators attached to the needle body; however these actuators usually involve heating that can thermally damage the tissue surrounding the needles. Therefore, to develop and access feasibility of these needles, a polyacrylamide gel has been developed that mimics the thermal damage and mechanical properties of prostate tissue. Mechanical properties of the polyacrylamide gel was controlled by varying the concentrations of acrylamide monomer and N,N-methylene-bisacrylamide (BIS) cross-linker, and thermal sensitivity was achieved by adding bovine serum albumin (BSA) protein. Two polyacrylamide gels with different concentrations were developed to mimic the elastic modulus of the tissue. The two phantoms showed different rupture toughness and different deflection of bevel-tip needle. To study the thermal damage, a Nitinol wire was embedded in the phantom and resistively heated. The measured opaque zone (0.40mm) formed around the wire was close to the estimated damage zone (0.43mm) determined using the cumulative equivalent minutes at 43°C.

A model to predict deflection of bevel-tipped active needle advancing in soft tissue.

Active needles are recently being developed to improve steerability and placement accuracy for various medical applications. These active needles can bend during insertion by actuators attached to their bodies. The bending of active needles enables them to be steered away from the critical organs on the way to target and accurately reach target locations previously unachievable with conventional rigid needles. These active needles combined with an asymmetric bevel-tip can further improve their steerability. To optimize the design and to develop accurate path planning and control algorithms, there is a need to develop a tissue-needle interaction model. This work presents an energy-based model that predicts needle deflection of active bevel-tipped needles when inserted into the tissue. This current model was based on an existing energy-based model for bevel-tipped needles, to which work of actuation was included in calculating the system energy. The developed model was validated with needle insertion experiments with a phantom material. The model predicts needle deflection reasonably for higher diameter needles (11.6% error), whereas largest error was observed for the smallest needle diameter (24.7% error).

A novel curvilinear approach for prostate seed implantation.

PURPOSE: A new technique called "curvilinear approach" for prostate seed implantation has been proposed. The purpose of this study is to evaluate the dosimetric benefit of curvilinear distribution of seeds for low-dose-rate (LDR) prostate brachytherapy. METHODS: Twenty LDR prostate brachytherapy cases planned intraoperatively with VariSeed planning system and I-125 seeds were randomly selected as reference rectilinear cases. All the cases were replanned by using curved-needle approach keeping the same individual source strength and the volume receiving 100% of prescribed dose 145 Gy (V(100)). Parameters such as number of needles, seeds, and the dose coverage of the prostate (D(90), V(150), V(200)), urethra (D(30), D(10)) and rectum (D(5), V(100)) were compared for the rectilinear and the curvilinear methods. Statistical significance was assessed using two-tailed student's t-test. RESULTS: Reduction of the required number of needles and seeds in curvilinear method were 30.5% (p < 0.001) and 11.8% (p < 0.49), respectively. Dose to the urethra was reduced significantly; D(30) reduced by 10.1% (p < 0.01) and D(10) reduced by 9.9% (p < 0.02). Reduction in rectum dose D(5) was 18.5% (p < 0.03) and V(100) was also reduced from 0.93 cc in rectilinear to 0.21 cc in curvilinear (p < 0.001). Also the V(150) and V(200) coverage of prostate reduced by 18.8% (p < 0.01) and 33.9% (p < 0.001), respectively. CONCLUSIONS: Significant improvement in the relevant dosimetric parameters was observed in curvilinear needle approach. Prostate dose homogeneity (V(150), V(200)) improved while urethral dose was reduced, which might potentially result in better treatment outcome. Reduction in rectal dose could potentially reduce rectal toxicity and complications. Reduction in number of needles would minimize edema and thereby could improve postimplant urinary incontinence. This study indicates that the curvilinear implantation approach is dosimetrically superior to conventional rectilinear implantation technique.