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The perforation characteristics and fracture-related mechanical properties of the tympanic membrane (TM) greatly affect surgical procedures like myringotomy and tympanostomy performed on the middle ear. We analyzed the most important features of the gerbil TM perforation using an experimental approach that was based on force measurement during a 2-cycle needle insertion/extraction process. Fracture energy, friction energy, strain energy, and hysteresis loss were taken into consideration for the analysis of the different stages of needle insertion and extraction. The results demonstrated that (1) although the TM shows viscoelastic behavior, the contribution of hysteresis loss was negligible compared to other irreversible dissipated energy components (i.e., fracture energy and friction energy). (2) The TM puncture force did not substantially change during the first hours after animal death, but interestingly, it increased after 1 week due to the drying effects of soft tissue. (3) The needle geometry affected the crack length and the most important features of the force-displacement plot for the needle insertion process (puncture force, puncture displacement, and jump-in force) increased with increasing needle diameter, whereas the insertion velocity only changed the puncture and jump-in forces (both increased with increasing insertion velocity) and did not have a noticeable effect on the puncture displacement. (4) The fracture toughness of the gerbil TM was almost independent of the needle geometry and was found to be around 0.33 ± 0.10 kJ/m2. [ABSTRACT FROM AUTHOR]

AbstractThe deflection modeling during the insertion of bevel-tipped flexible needles into soft tissues is crucial for robot-assisted flexible needle insertion into specific target locations within the human body during percutaneous biopsy surgery. This paper proposes a mechanical model based on cutting force identification to predict the deflection of flexible needles in soft tissues. Unlike other models, this method does not require measuring Young’s modulus (E) and Poisson’s ratio (ν) of tissues, which require complex hardware to obtain. In the model, the needle puncture process is discretized into a series of uniform-depth puncture steps. The needle is simplified as a cantilever beam supported by a series of virtual springs, and the influence of tissue stiffness on needle deformation is represented by the spring stiffness coefficient of the virtual spring. By theoretical modeling and experimental parameter identification of cutting force, the spring stiffness coefficients are obtained, thereby modeling the deflection of the needle. To verify the accuracy of the proposed model, the predicted model results were compared with the deflection of the puncture experiment in polyvinyl alcohol (PVA) gel samples, and the average maximum error range predicted by the model was between 0.606 ± 0.167 mm and 1.005 ± 0.174 mm, which showed that the model can successfully predict the deflection of the needle. This work will contribute to the design of automatic control strategies for needles. [ABSTRACT FROM AUTHOR]

CT angiography might be a suitable procedure to avoid arterial puncture in combined intracavitary and interstitial brachytherapy for cervical cancer curatively treated with combined chemoradiation and brachytherapy boost. Data in the literature about this technique are scarce. We introduced this method and collected brachytherapy data from patients treated in our department between May 2021 and April 2024. We analyzed the applicator subtype, needle insertion (planned versus implanted), implanted depth and the role of CT angiography in selecting needle trajectories and insertion depths. None of the patients managed through this protocol experienced atrial puncture and consequent hemorrhage. Needle positions were accurately selected with the aid of CT angiography with proper coverage of brachytherapy targets and avoidance of organs at risk. CT angiography is a promising method for guiding needle insertion during interstitial brachytherapy. [ABSTRACT FROM AUTHOR]

Although intravitreal (IVT) injections provide several advantages in treating posterior segment eye diseases, several associated challenges remain. The current study uses the finite element method (FEM) to highlight the effect of IVT needle rotation along the insertion axis on the reaction forces and deformation inside the eye. A comparison of the reaction forces at the eye's key locations has been made with and without rotation. In addition, a sensitivity analysis of various parameters, such as the needle's angular speed, insertion location, angle, gauge, shape, and intraocular pressure (IOP), has been carried out to delineate the individual parameter's effect on reaction forces during rotation. Results demonstrate that twisting the needle significantly reduces the reaction forces at the penetration location and throughout the needle travel length, resulting in quicker penetration. Moreover, ocular biomechanics are influenced by needle insertion location, angle, shape, size, and IOP. The reaction forces incurred by the patient may be reduced by using a bevel needle of the higher gauge when inserted close to the normal of the local scleral surface toward the orra serrata within the Pars Plana region. Results obtained from the current study can deepen the understanding of the twisting needle's interaction with the ocular tissue. [ABSTRACT FROM AUTHOR]

This study evaluates the efficacy of Dynamic Needle Guidance (DNG) and Dynamic Needle Tip Positioning (DNTP) in the context of sports-related medical interventions, focusing on their potential to improve the administration of nutritional supplements and medications that support athlete recovery and performance. Thirty-one novice residents performed vascular access procedures using both technologies on a phantom model in a randomized sequence. Our primary endpoint was operation time, with secondary endpoints including puncture time, the number of needle tip adjustments tracked by ultrasound, and success rates of initial punctures and attempts, as well as operation difficulty scores. The findings indicated that DNG significantly reduced the operation time (mean(SD) 24.2 (6.4) s vs. 49.4 (15.8) s; p=0.000) and puncture time (9.6 (2.3) s vs. 31.1 (9.8) s; p=0.000), with fewer median (IQR[range]) needle tip adjustments (1 (1-1) [1-1] vs. 3 (3-4) [2-6]; p=0.000). These results suggest a higher efficiency and potentially less discomfort for athletes undergoing treatment. No significant differences were noted in the first puncture or first-attempt success rates between the two methods. Participants reported a significantly lower mean(SD) operation difficulty with DNG compared to DNTP (3.3 (1.0) vs. 6.7 (1.2); p=0.000). The use of DNG could significantly enhance the precision and speed of treatments involving vascular access in athletes, suggesting its potential as a beneficial tool in sports medicine to accelerate recovery and return to performance. [ABSTRACT FROM AUTHOR]

Purpose: Hollow-type microneedles (hMNs) are a promising device for the effective administration of drugs into intradermal sites. Complete insertion of the needle into the skin and administration of the drug solution without leakage must be achieved to obtain bioavailability or a constant effect. In the present study, several types of hMN with or without a rounded blunt tip micropillar, which suppresses skin deformation, around a hollow needle, and the effect on successful needle insertion and administration of a drug solution was investigated. Six different types of hMNs with needle lengths of 1000, 1300, and 1500 µm with or without a micropillar were used. Methods: Needle insertion and the disposition of a drug in rat skin were investigated. In addition, the displacement-force profile during application of hMNs was also investigated using a texture analyzer with an artificial membrane to examine needle factors affecting successful insertion and administration of a drug solution by comparing with in vivo results. Results: According to the results with the drug distribution of iodine, hMN1300 with a micropillar was able to successfully inject drug solution into an intradermal site with a high success rate. In addition, the results of displacement-force profiles with an artificial membrane showed that a micropillar can be effective for depth control of the injected solution as well as the prevention of contact between the hMN pedestal and the deformed membrane. Conclusion: In the present study, hMN1300S showed effective solution delivery into an intradermal site. In particular, a micropillar can be effective for depth control of the injected solution as well as preventing contact between the hMN pedestal and the deformed membrane. The obtained results will help in the design and development of hMNs that ensure successful injection of an administered drug. [ABSTRACT FROM AUTHOR]

Medical needle innovations have utilized rotating motion to enhance tissue-cutting capabilities, reducing cutting force and improving clinical outcomes. This study analyzes the effects of six essential factors on insertion and extraction forces during bone marrow biopsy (BMB) procedures. The study uses Taguchi's L32 orthogonal array and numerically simulates the BMB process using the Lagrangian surface-based method on a three-dimensional (3D) heterogeneous Finite Element (FE) model of the human iliac crest. The study evaluates cutting forces in needle insertion and extraction using uni-directional (360° rotation) and bidirectional (180° clock and anti-clock rotation) bioinspired BMB needles. This work aims to create an AI tool that assists researchers and clinicians in selecting the most suitable and safe design parameters for a bio-inspired barbed biopsy needle. An efficient Graphical User Interface (GUI) has been developed for easy use and seamless interaction with the AI tool. With a remarkable accuracy rate exceeding 98%, the tool's predictions hold significant value in facilitating the development of environmentally conscious biopsy needles. The tool demonstrates significantly higher efficiency compared to Abaqus, rendering it a valuable asset for researchers and clinicians engaged in bio-inspired biopsy needle development. [ABSTRACT FROM AUTHOR]

ABSTRACTPercutaneous needle insertion constitutes a widely adopted technique for performing minimally invasive operations. Robot-assisted needle placement and virtual surgical training platforms have the potential to significantly improve the accuracy of these operations. For this, the development of mathematical models that provide a complete characterization of the underlying dynamics of medical needles is considered of paramount importance. In this paper, we develop two three-dimensional nonlinear rigid/flexible dynamic models of brachytherapy and local anaesthetic transperineal biopsy (LATP) needles. The proposed models relax the assumptions of previous investigations, quantify the vibrational behaviour and the rigid-body dynamics of medical needles and allow for real-time haptic and visual feedback information. Their accuracy and computational efficiency are assessed and validated using commercial software. The results show that, among the examined methods, the Rigid Finite Element Method provides the most accurate and numerically efficient solution for capturing the dynamics of flexible medical needles.

Percutaneous needle insertion constitutes a widely adopted technique for performing minimally invasive operations. Robot-assisted needle placement and virtual surgical training platforms have the potential to significantly improve the accuracy of these operations. For this, the development of mathematical models that provide a complete characterization of the underlying dynamics of medical needles is considered of paramount importance. In this paper, we develop two three-dimensional nonlinear rigid/flexible dynamic models of brachytherapy and local anaesthetic transperineal biopsy (LATP) needles. The proposed models relax the assumptions of previous investigations, quantify the vibrational behaviour and the rigid-body dynamics of medical needles and allow for real-time haptic and visual feedback information. Their accuracy and computational efficiency are assessed and validated using commercial software. The results show that, among the examined methods, the Rigid Finite Element Method provides the most accurate and numerically efficient solution for capturing the dynamics of flexible medical needles. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to evaluate the morphology of the three parts of the infraspinatus muscle based on surface landmarks for precise and effective access, and to propose the most effective fine-wire electrode insertion technique and sites. Methods: Fifteen Asian fresh cadavers were used. We investigated the probability of the presence of the superior, middle, and inferior parts in each infraspinatus muscle based on surface landmarks. Based on the positional characteristics of the muscle, we determined the needle insertion method and confirmed its effectiveness by dissection. Results: The superior part was mostly observed near the spine of the scapula. The middle part was broadly observed within the infraspinous fossa. The inferior part showed variable location within the infraspinous fossa. The injection accuracy of the superior, middle, and inferior parts in the infraspinatus muscle was 95.8%, 100%, and 91.7%, respectively. Targeting the superior and middle parts for injection of the infraspinatus muscle is relatively more straightforward than targeting the inferior part. Targeting the inferior part of the infraspinatus muscle in this study was more challenging than targeting the superior and middle parts. Conclusion: Needling for electromyography should be performed with special care to avoid unintended muscle parts, which could lead to inaccurate data acquisition and affect the conclusions about muscle function. [ABSTRACT FROM AUTHOR]

CT angiography might be a suitable procedure to avoid arterial puncture in combined intracavitary and interstitial brachytherapy for cervical cancer curatively treated with combined chemoradiation and brachytherapy boost. Data in the literature about this technique are scarce. We introduced this method and collected brachytherapy data from patients treated in our department between May 2021 and April 2024. We analyzed the applicator subtype, needle insertion (planned versus implanted), implanted depth and the role of CT angiography in selecting needle trajectories and insertion depths. None of the patients managed through this protocol experienced atrial puncture and consequent hemorrhage. Needle positions were accurately selected with the aid of CT angiography with proper coverage of brachytherapy targets and avoidance of organs at risk. CT angiography is a promising method for guiding needle insertion during interstitial brachytherapy.

Abstract Objective A neural network method was employed to establish a dose prediction model for organs at risk (OAR) in patients with cervical cancer receiving brachytherapy using needle insertion. Methods A total of 218 CT-based needle-insertion brachytherapy fraction plans for loco-regionally advanced cervical cancer treatment were analyzed in 59 patients. The sub-organ of OAR was automatically generated by self-written MATLAB, and the volume of the sub-organ was read. Correlations between D2cm3 of each OAR and volume of each sub-organ—as well as high-risk clinical target volume for bladder, rectum, and sigmoid colon—were analyzed. We then established a neural network predictive model of D2cm3 of OAR using the matrix laboratory neural net. Of these plans, 70% were selected as the training set, 15% as the validation set, and 15% as the test set. The regression R value and mean squared error were subsequently used to evaluate the predictive model. Results The D2cm3/D90 of each OAR was related to volume of each respective sub-organ. The R values for bladder, rectum, and sigmoid colon in the training set for the predictive model were 0.80513, 0.93421, and 0.95978, respectively. The ∆D2cm3/D90 for bladder, rectum, and sigmoid colon in all sets was 0.052 ± 0.044, 0.040 ± 0.032, and 0.041 ± 0.037, respectively. The MSE for bladder, rectum, and sigmoid colon in the training set for the predictive model was 4.779 × 10−3, 1.967 × 10−3 and 1.574 × 10−3, respectively. Conclusion The neural network method based on a dose-prediction model of OAR in brachytherapy using needle insertion was simple and reliable. In addition, it only addressed volumes of sub-organs to predict the dose of OAR, which we believe is worthy of further promotion and application.

Purpose: Percutaneous fracture fixation involves multiple X-ray acquisitions to determine adequate tool trajectories in bony anatomy. In order to reduce time spent adjusting the X-ray imager's gantry, avoid excess acquisitions, and anticipate inadequate trajectories before penetrating bone, we propose an autonomous system for intra-operative feedback that combines robotic X-ray imaging and machine learning for automated image acquisition and interpretation, respectively. Methods: Our approach reconstructs an appropriate trajectory in a two-image sequence, where the optimal second viewpoint is determined based on analysis of the first image. A deep neural network is responsible for detecting the tool and corridor, here a K-wire and the superior pubic ramus, respectively, in these radiographs. The reconstructed corridor and K-wire pose are compared to determine likelihood of cortical breach, and both are visualized for the clinician in a mixed reality environment that is spatially registered to the patient and delivered by an optical see-through head-mounted display. Results: We assess the upper bounds on system performance through in silico evaluation across 11 CTs with fractures present, in which the corridor and K-wire are adequately reconstructed. In post hoc analysis of radiographs across 3 cadaveric specimens, our system determines the appropriate trajectory to within 2.8 ± 1.3 mm and 2.7 ± 1.8 ∘ . Conclusion: An expert user study with an anthropomorphic phantom demonstrates how our autonomous, integrated system requires fewer images and lower movement to guide and confirm adequate placement compared to current clinical practice. Code and data are available. [ABSTRACT FROM AUTHOR]

The main aim of this work is to use a finite element technique (FEM) to gain understanding about the bone marrow biopsy (BMB) needle insertion process and needle-tissue interactions in the human iliac crest. A multi-layer iliac crest model consists of stratum corneum, dermis, epidermis, hypodermis, cortical, and cancellous bone has been established. This paper proposes a FE model that examines all phases of tissue deformation, including puncture, cutting, needle-tissue interaction, and various stress-strain values for BMB needle during interaction. The results explain the needle-tissue interface and show the potential of this technique to estimate bone damage and tissue deformation for multiple needle dimensions, coefficient of friction, and penetration speeds. The insertion and extraction force of conical-shaped needles in the multi-layered iliac crest model decreased by 18.92% and 37.5%, respectively, as the needle diameter reduced from 11 G to 20 G. It has also been found that the significant insertion motion raises the deformation of the tissue due to the augmented frictional forces but reduces the strain perpendicular to the penetration direction closer to the needle tip. The simulation outcomes are helpful for the optimal design of fine biopsy needles used to perform the bone marrow biopsies. [ABSTRACT FROM AUTHOR]

Abstract The simulation and planning system (SPS) requires accurate and real-time feedback regarding the deformation of soft tissues during the needle insertion procedure. Traditional mechanical-based models such as the finite element method (FEM) are widely used to compute the deformations of soft tissue. However, it is difficult for the FEM or other methods to find a balance between an acceptable image fidelity and real-time deformation feedback due to their complex material properties, geometries and interaction mechanisms. In this paper, a Kriging-based method is applied to model the soft tissue deformation to strike a balance between the accuracy and efficiency of deformation feedback. Four combinations of regression and correlation functions are compared regarding their ability to predict the maximum deformations of ten characteristic markers at a fixed insertion depth. The results suggest that a first order regression function with Gaussian correlation functions can best fit the results of the ground truth. The functional response of the Kriging-based method is utilized to model the dynamic deformations of markers at a series of needle insertion depths. The feasibility of the method is verified by investigating the adaptation to step variations. Compared with the ground truth of the finite element (FE) results, the maximum residual is less than 0.92 mm in the Y direction and 0.31 mm in the X direction. The results suggest that the Kriging metamodel provides real-time deformation feedback for a target and an obstacle to a SPS.

Objective: A neural network method was employed to establish a dose prediction model for organs at risk (OAR) in patients with cervical cancer receiving brachytherapy using needle insertion. Methods: A total of 218 CT-based needle-insertion brachytherapy fraction plans for loco-regionally advanced cervical cancer treatment were analyzed in 59 patients. The sub-organ of OAR was automatically generated by self-written MATLAB, and the volume of the sub-organ was read. Correlations between D2cm3 of each OAR and volume of each sub-organ—as well as high-risk clinical target volume for bladder, rectum, and sigmoid colon—were analyzed. We then established a neural network predictive model of D2cm3 of OAR using the matrix laboratory neural net. Of these plans, 70% were selected as the training set, 15% as the validation set, and 15% as the test set. The regression R value and mean squared error were subsequently used to evaluate the predictive model. Results: The D2cm3/D90 of each OAR was related to volume of each respective sub-organ. The R values for bladder, rectum, and sigmoid colon in the training set for the predictive model were 0.80513, 0.93421, and 0.95978, respectively. The ∆D2cm3/D90 for bladder, rectum, and sigmoid colon in all sets was 0.052 ± 0.044, 0.040 ± 0.032, and 0.041 ± 0.037, respectively. The MSE for bladder, rectum, and sigmoid colon in the training set for the predictive model was 4.779 × 10−3, 1.967 × 10−3 and 1.574 × 10−3, respectively. Conclusion: The neural network method based on a dose-prediction model of OAR in brachytherapy using needle insertion was simple and reliable. In addition, it only addressed volumes of sub-organs to predict the dose of OAR, which we believe is worthy of further promotion and application. [ABSTRACT FROM AUTHOR]

Surgical needle insertion is generally used in the current advanced surgery process, particularly in the area of biopsy, MIS or minimally invasive surgery, brachytherapy, etc. During the needle insertion performance into the soft tissue, one of the most important issues is the tissue deformation that affects the needle engagement inside the tissue material. We have presented an energy-based insertion model, and the conical shape of deformed tissue is assumed. The tests are performed on PVA gel samples, and the model is analyzed to determine the tissue deformation volume during needle insertion into soft tissue. The procedures for evaluating the puncture force which creates the deformation of the contact point. With the help of the needle insertion experimental investigation, a geometric model of tissue deformation phenomenon and insertion force was investigated. The active needle-soft tissue contacts are studied, and with the help of the energy-based insertion model, the different factors like strain energy, potential, and dissipated energies are investigated. The tests are completed on the tissue mimic PVA gel samples, and the results show the volume and area of tissue deformation; at the time of initial needle insertion, the maximum tissue deformation arises and during the needle movement in the post-perforation stage, the deformation gradually decreases as the more peripheral work is altered into the vicious and degenerate energies. The maximum insertion force was noticed in 14° bevel angle needle tip and at 3 mm/s needle insertion speed, the volume of tissue deformation was maximum. The maximum deformation of the issue arises at the initial perforate position, and the distortion reduces along with the raises of the needle movement during the post-insertion period as the needle insertion work is converted into vicious and dissolute energies. [ABSTRACT FROM AUTHOR]

The surgical needle insertion process is widely applied in medical interference. During the insertion process, the inhomogeneity and denseness of the soft tissues make it tough to detect the essential tissue damage, a rupture occurs that contains huge forces and material deformations. This study is very important, as all the above-mentioned factors are very significant for modern invasive surgery so that the success rate of the surgery can increase and the patient recovers smoothly. This investigation intends to perform minimally invasive surgical (MIS) procedures and reduce the living tissue damage while performing the biopsy, PCNL, etc. A fracture mechanics method was analyzed to create a needle insertion model which can estimate the needle insertion force during inset in tissue-like PVA gel. The force model was calculated by needle insertion experimentally, and also estimated the needle tip geometry, and diameter influences the fracture toughness. Validate exp. results with simulation results and other papers. It is observed that needle diameter has a significant effect on fracture toughness, whereas the insertion velocity has a slight impact on the fracture toughness. During the rotational needle insertion process, the winds-up of the gel occurs and the diameter of the hole was increasing with increased rpm. Maximum insertion force was noticed in the 27 G needle at 5 mm/s. The interaction function will be less at the maximum fracture development region. Graphical abstract [ABSTRACT FROM AUTHOR]

• Finite-element analysis offers insights into needle-TM interactions for middle-ear interventions. • Combined 2D and 3D FE modeling strategy reveals TM deformation during needle insertion. • First-order Ogden hyperelastic model accurately captures TM mechanical nonlinearity. • TM thickness, needle geometry, and material impact needle insertion force and success. • Methodology aids in developing therapeutic and diagnostic technologies for hearing and balance pathologies. The tympanic membrane (TM) is one of the most common routes to access the middle ear and inner ear for the treatment of hearing and balance pathologies. Since the TM is a soft thin biological tissue with small dimensions, using needles seems to be among the most practical interventional approaches. In this study, we proposed a finite-element (FE) analysis of needle-TM interactions that combines a 3D model of the TM and other main middle-ear structures in gerbil, and a 2D model of needle insertion into the TM based on the cohesive zone method (CZM). The TM was modelled using a 1st-order Ogden hyperelastic material and its properties were obtained by fitting to the experimental force-displacement plots of large deformation in the TM under needle indentation. The cohesive parameters were also acquired by calibrating the puncture force against the experimental data of needle insertion into the TM. These FE models were then used to obtain the deformation behaviour of the TM and other middle-ear structures due to the insertion force applied at different locations on the TM. Moreover, we investigated the effect of the TM thickness, the geometry of the needle (i.e., diameter and tip angle), and needle material on the insertion of needles into the TM. We also studied the penetration success of deformable needles. [ABSTRACT FROM AUTHOR]

Purpose: The Baker’s cysts appear within the popliteal fossa along with the progression of degenerative changes. Removal of its contents through aspiration is often a necessary complement to treatment at various stages of the development of gonarthritis. Methods: The paper presented a procedure for needle automatic needle path planning in cyst aspiration in transverse plane. The method was based on optimization and used a custom objective function, which utilized cost maps obtained from preprocessed, segmented images of the knee. The optimization was carried out with Differential Evolution. Furthermore, a preliminary sensitivity analysis was carried out. The obtained paths were compared to the reference paths proposed by an experienced surgeon. Results: The procedure was tested on 165 numerical simulations. In all of the obtained paths, the needle successfully avoided crucial objects, such as veins, arteries and nerves. Furthermore, the overall travel distance in the joint was also minimized. When compared to the reference from the surgeon, 90% of the paths were almost the same or only slightly different. Furthermore, the remaining 10% of the generated paths were viable but different. Conclusion: Based on the obtained results, the proposed solution could be a viable solution for planning the aspiration of Baker’s cyst. [ABSTRACT FROM AUTHOR]

The simulation and planning system (SPS) requires accurate and real-time feedback regarding the deformation of soft tissues during the needle insertion procedure. Traditional mechanical-based models such as the finite element method (FEM) are widely used to compute the deformations of soft tissue. However, it is difficult for the FEM or other methods to find a balance between an acceptable image fidelity and real-time deformation feedback due to their complex material properties, geometries and interaction mechanisms. In this paper, a Kriging-based method is applied to model the soft tissue deformation to strike a balance between the accuracy and efficiency of deformation feedback. Four combinations of regression and correlation functions are compared regarding their ability to predict the maximum deformations of ten characteristic markers at a fixed insertion depth. The results suggest that a first order regression function with Gaussian correlation functions can best fit the results of the ground truth. The functional response of the Kriging-based method is utilized to model the dynamic deformations of markers at a series of needle insertion depths. The feasibility of the method is verified by investigating the adaptation to step variations. Compared with the ground truth of the finite element (FE) results, the maximum residual is less than 0.92 mm in the Y direction and 0.31 mm in the X direction. The results suggest that the Kriging metamodel provides real-time deformation feedback for a target and an obstacle to a SPS. [ABSTRACT FROM AUTHOR]

The perforation characteristics and fracture-related mechanical properties of the tympanic membrane (TM) greatly affect surgical procedures like myringotomy and tympanostomy performed on the middle ear. We analyzed the most important features of the gerbil TM perforation using an experimental approach that was based on force measurement during a 2-cycle needle insertion/extraction process. Fracture energy, friction energy, strain energy, and hysteresis loss were taken into consideration for the analysis of the different stages of needle insertion and extraction. The results demonstrated that (1) although the TM shows viscoelastic behavior, the contribution of hysteresis loss was negligible compared to other irreversible dissipated energy components (i.e., fracture energy and friction energy). (2) The TM puncture force did not substantially change during the first hours after animal death, but interestingly, it increased after 1 week due to the drying effects of soft tissue. (3) The needle geometry affected the crack length and the most important features of the force-displacement plot for the needle insertion process (puncture force, puncture displacement, and jump-in force) increased with increasing needle diameter, whereas the insertion velocity only changed the puncture and jump-in forces (both increased with increasing insertion velocity) and did not have a noticeable effect on the puncture displacement. (4) The fracture toughness of the gerbil TM was almost independent of the needle geometry and was found to be around 0.33 ± 0.10 kJ/m 2 ., (© 2024. The Author(s) under exclusive licence to Association for Research in Otolaryngology.)

Purpose: Breast cancer is currently the cancer type with the highest incidence in the world, and it is extremely harmful to women's health. MRI-guided breast biopsy is a common method in clinical examination of breast cancer. However, traditional breast biopsy is less accurate and takes a long time. In this study, an integrated navigation system (INS) based on a dedicated breast support device (DBSD) was proposed to assist doctors in biopsy. Methods: The grid-shaped DBSD can reduce the displacement and deformation of the breast during the biopsy operation and is convenient for puncture. The robot system based on the DBSD is designed to assist doctors in performing puncture action. The software system has functions such as registration, path planning, and real-time tracking of biopsy needles based on the DBSD, which can assist doctors in completing the entire biopsy procedure. A series of experiments are designed to verify the feasibility and accuracy of the system. Results: Experiments prove that the robot system has reasonable structure and meets the requirements of MR compatibility. The latency of the INS during intraoperative navigation is 0.30 ± 0.03 s. In the phantom puncture experiment, the puncture error under the navigation of the INS is 1.04 ± 0.15 mm. Conclusion: The INS proposed in this paper can be applied to assist doctors in breast biopsy in MR environment, improve the accuracy of biopsy and shorten the time of biopsy. The experimental results show that the system is feasible and accurate. [ABSTRACT FROM AUTHOR]

Percutaneous needle-based interventions such as transperineal prostate brachytherapy require the accurate placement of multiple needles to treat cancerous lesions within the target organ. To guide needle placement, magnetic resonance imaging (MRI) offers excellent visualization of the target lesion without the need for ionizing radiation. To date, multi-needle insertion relies on a grid template, which limits the ability to steer individual needles. This work describes an MR-compatible robot designed for the sequential insertion of multiple non-parallel needles under MR guidance. The 6-DOF system is designed with an articulated arm to extend the reach of the robot. This strategy presents a novel approach enabling the robot to maneuver around existing needles while minimizing the footprint of the robot. Forward kinematics as well as optimization-based inverse kinematics are presented. The impact of the robot on image quality was tested for four sequences (T1w-TSE, T2w-TSE, THRIVE and EPI) on a 3T Philips Achieva system. Quantification of the signal-to-noise ratio showed a 46% signal loss in a gelatin phantom when the system was powered on but no further adverse effects when the robot was moving. Joint level testing showed a maximum error of 2.10 ± 0.72°s for revolute joints and 0.31 ± 0.60 mm for prismatic joints. The theoretical workspace spans the proposed clinical target surface of 10 x 10 cm. Lastly, the feasibility of multi-needle insertion was demonstrated with four needles inserted under real-time MR-guidance with no visible loss in image quality. [ABSTRACT FROM AUTHOR]

Abstract High repeatability of needle insertion experiments is essential to the needle-phantom interaction model validation. However, the influential factors governing the accuracy of the phantom and needle deformations have not been systematically studied. In this paper, the impact of influential factors, including phantom characteristic represented by the ratio of DMSO and thawing time (TT), needle properties represented by needle external diameter (NED) and operating factors such as needle insertion velocity (IV), insertion positions (IP) and repeated insertion times (RITs) are analyzed by orthogonal experiment design. The range calculation shows the most sensitive parameters to phantom deformations are RITs, IV and DMSO while the most sensitive parameters to needle deflection are DMSO, TT and NED. By variance analysis, the significant factors on maximum tissue deformation (MTD) are IV, followed by RITs, DMSO and IP. And NED and TT have nearly no significant impact on MTD. The significant sequence on maximum needle deflection (MND) is as follows: DMSO, TT and NED. Results show that, among all impacting factors, phantom deformation is susceptible to both material properties and operative factors while the needle deflection is more susceptible to material properties of the phantom, which can help researchers in related fields to conduct experiments in a more precise manner and better understand the needle-phantom interaction mechanism.

Percutaneous needle-based interventions such as transperineal prostate brachytherapy require the accurate placement of multiple needles to treat cancerous lesions within the target organ. To guide needle placement, magnetic resonance imaging (MRI) offers excellent visualization of the target lesion without the need for ionizing radiation. To date, multi-needle insertion relies on a grid template, which limits the ability to steer individual needles. This work describes an MR-compatible robot designed for the sequential insertion of multiple non-parallel needles under MR guidance. The 6-DOF system is designed with an articulated arm to extend the reach of the robot. This strategy presents a novel approach enabling the robot to maneuver around existing needles while minimizing the footprint of the robot. Forward kinematics as well as optimization-based inverse kinematics are presented. The impact of the robot on image quality was tested for four sequences (T1w-TSE, T2w-TSE, THRIVE and EPI) on a 3T Philips Achieva system. Quantification of the signal-to-noise ratio showed a 46% signal loss in a gelatin phantom when the system was powered on but no further adverse effects when the robot was moving. Joint level testing showed a maximum error of 2.10 ± 0.72°s for revolute joints and 0.31 ± 0.60 mm for prismatic joints. The theoretical workspace spans the proposed clinical target surface of 10 x 10 cm. Lastly, the feasibility of multi-needle insertion was demonstrated with four needles inserted under real-time MR-guidance with no visible loss in image quality.

Modelling of needle insertion in soft tissue has developed significant interest in recent years due to its application in robot-assisted minimally invasive surgeries such as biopsies and brachytherapy. However, this type of surgery requires real-time feedback and processing which complex computational models may not be able to provide. In contrast to the existing mechanics-based kinetic models, a simple multilayer tissue model using a Coupled Eulerian Lagrangian based Finite Element method has been developed using the dynamic principle. The model simulates the needle motion for flexible hollow bevel-angled needle (15° and 30°, 22 Gauge) insertion into porcine liver tissue, which includes material parameters obtained from unconfined compression testing of porcine liver tissue. To validate simulation results, needle insertion force and cutting force within porcine liver tissue were compared with corresponding experimental results obtained from a custom-built needle insertion system. For the 15° and 30° bevel-angle needles, the percentage error for cutting force (mean) of each needle compared to computational model, were 18.7% and 11.9% respectively. Varying the needle bevel angle from 30° to 15° results in an increase of the cutting force, but insertion force does not vary among the tested bevel angles. The validation of this computationally efficient multilayer Finite Element model can help engineers to better understand the biomechanical behaviour of medical needle inside soft biological tissue. Ultimately, this multilayer approach can help advance state-of-art clinical applications such as robot-assisted surgery that requires real-time feedback and processing. The significance of the work is in confirming the effectiveness of multilayer material based finite element (FE) method to model biopsy needle insertion into soft biological porcine liver tissue. A multilayer Coupled Eulerian Lagrangian (CEL) based FE modelling technique allowed testing of heterogeneous, non-linear viscoelastic porcine liver tissue in a system, so direct comparison of needle tissue interaction forces on the intrinsic material (tissue) behaviour could be made. To the best of the authors' knowledge, the present research investigates for the first time modelling of a three dimensional (3D) hollow needle insertion using a multilayer stiffness model of biological tissue using FE based CEL method and presents a comparison of simulation results with experimental data. [Display omitted] [ABSTRACT FROM AUTHOR]

Purpose: To assess accuracy and compare protocols for CT-guided needle insertion for clinical biopsies using a hands-free robotic system, balancing system accuracy with duration of procedure and radiation dose. Methods: Thirty-two percutaneous abdominal and pelvic biopsies were performed and analyzed at two centers (Center 1 n = 11; Center 2 n = 21) as part of an ongoing prospective, multi-center study. CT datasets were obtained for planning and controlled placement of 17 g needles using a patient-mounted, CT-guided robotic system. Planning included target selection, skin entry point, and predetermined checkpoints. Additional CT imaging was performed at checkpoints to confirm needle location and permit stepwise correction of the trajectory. Center 1 used a more conservative approach with multiple checkpoints, whereas Center 2 used fewer checkpoints. Scanning and needle advancement were performed under respiratory gating. Accuracy, radiation dose, and steering duration were compared. Results: Overall accuracy was 1.6 ± 1.5 mm (1.9 ± 1.2 mm Center 1; 1.5 ± 1.6 mm Center 2; p = 0.55). Mean distance to target was 86.2 ± 27.1 mm (p = 0.18 between centers). Center 1 used 4.6 ± 0.8 checkpoints, whereas Center 2 used 1.8 ± 0.6 checkpoints (p < 0.001). Effective radiation doses were lower for Center 1 than for Center 2 (22.2 ± 12.6 mSv vs. 11.7 ± 4.3 mSv; p = 0.002). Likewise, steering duration (from planning to target) was significantly reduced in relation to the number of checkpoints from 43.8 ± 15.9 min for Center 1 to 30.5 ± 10.2 min for Center 2 (p = 0.008). Conclusions: Accurate needle targeting with < 2 mm error can be achieved in patients when using a CT-guided robotic system. Judicious selection of the number of checkpoints may substantially reduce procedure time and radiation dose without sacrificing accuracy. [ABSTRACT FROM AUTHOR]

Needle-tissue interaction model is essential to tissue deformation prediction, interaction force analysis and needle path planning system. Traditional FEM based needle-tissue interaction model would encounter mesh distortion or continuous mesh subdivision in dealing with penetration, in which the computational instability and poor accuracy could be introduced. In this work, a novel material point method (MPM) is applied to establish the needle-tissue interaction model which is suitable to handle the discontinuous penetration problem. By integrating a hyperelastic material model, the tissue deformation and interaction force can be solved simultaneously and independently. A testbed of needle insertion into a Polyvinyl alcohol (PVA) hydrogel phantom was constructed to validate both tissue deformation and interaction force. The results showed the experimental data agrees well with the simulation results of the proposed model. [ABSTRACT FROM AUTHOR]

Purpose: Percutaneous image‐guided interventions are commonly used for the diagnosis and treatment of cancer. In practice, physiological breathing‐induced motion increases the difficulty of accurately inserting needles into tumors without impairing the surrounding vital structures. In this work, we propose a data‐driven patient‐specific hierarchical respiratory motion estimation framework to accurately estimate the position of a tumor and surrounding vital tissues in real time. Methods: The motion of optical markers attached to the chest or abdomen skin is used as a surrogate signal to estimate tumor motion based on ɛ‐support vector regression (ɛ‐SVR). With the estimated tumor motion as the input, a novel respiratory motion model is developed to estimate the diffeomorphic deformation field of the whole organ (liver or lung) without intraoperative, iterative optimization computations. The respiratory motion model of the whole organ is established in Lie algebra space based on the kriging algorithm to ensure that the estimated deformation field is diffeomorphic, optimal, and unbiased. Preoperative prior knowledge for modeling the motion of whole organs is obtained by deformation registration between four‐dimensional computed tomography (4D CT) images using a hybrid diffeomorphic registration method. Results and Conclusions: Experimental results on an in vivo beagle dog show that the minimum value of the determinant of the Jacobian of the estimated deformation field is greater than zero, so the estimated deformation field of the whole liver with our method is diffeomorphic. The mean position error of the tumor is 1.2 mm corresponding to a mean accuracy improvement of 76.5%, and the mean position error of the whole liver is 2.1 mm, corresponding to a mean accuracy improvement of 37.9%. The experimental results based on public human subject data show that the mean position error of the tumor is 1.1 mm, corresponding to a mean accuracy improvement of 83.1%, and the mean position error of the whole lung is 2.1 mm, corresponding to a mean accuracy improvement of 41.4%. The positioning errors for the tumor and whole organ are hierarchical and consistent with clinical demand. [ABSTRACT FROM AUTHOR]

Percutaneous needle insertion is a widely used technique in needle-based intervention; however, it is difficult to achieve high targeting accuracy due to needle deflection and the boundary effect in multilayered tissues. This article presents a preoperative needle insertion trajectory planning method that includes needle deflection modeling, insertion angle correction, and needle trajectory optimization. The needle deflection model can predict the needle deflection with preoperatively obtained information, which includes tissue-specific parameters and the geometric/material properties of the needle. An insertion angle shift distribution model is obtained based on experimental data and is used to correct insertion angles at tissue boundaries. The needle trajectory optimization is based on the weighted sum of cost function and balances the assessment criteria, which include the trajectory length, the insertion angle, and the distance to critical structures, and determines the needle trajectory with the best performance. Experiments are conducted to demonstrate that with the proposed preoperative needle insertion trajectory planning method, a needle insertion trajectory with increased accuracy, desired insertion length, and safe distance to critical structures can be obtained. [ABSTRACT FROM AUTHOR]

Purpose: Ultrasound (US)-guided percutaneous puncture technology can realize real-time, minimally invasive interventional therapy without radiation. The location accuracy of the puncture needle directly determines the precision and safety of the operation. It is a challenge for novices and young surgeons to perform a free-hand puncture guided by the ultrasound images to achieve the desired accuracy. This work aims to develop a robotic system to assist surgeons to perform percutaneous punctures with high precision. Methods: An US-guided puncture robot was designed to allow the mounting and control of the needle to achieve localization and insertion. The US probe fitted within the puncture robot was held by a passive arm. Moreover, the puncture robot was calibrated with a novel calibration method to achieve coordinate transformation between the robot and the US image. The system allowed the operators to plan the puncture target and puncture path on US images, and the robot performed needle insertion automatically. Five groups of puncture experiments were performed to verify the validity and accuracy of the proposed robotic system. Results: Assisted by the robotic system, the positioning and orientation accuracies of the needle insertion were 0.9 ± 0.29 mm and 0.76 ± 0.34°, respectively. These are improved compared with the results obtained with the free-hand puncture (1.82 ± 0.51 mm and 2.79 ± 1.32°, respectively). Moreover, the proposed robotic system can reduce the operation time and number of needle insertions (14.28 ± 3.21 s and one needle insertion, respectively), compared with the free-hand puncture (25.14 ± 6.09 s and 1.96 ± 0.68 needle insertions, respectively). Conclusion: A robotic system for percutaneous puncture guided by US images was developed and demonstrated. The experimental results indicate that the proposed system is accurate and feasible. It can assist novices and young surgeons to perform the puncture operation with increased accuracy. [ABSTRACT FROM AUTHOR]

We present a study in human-centered automation that has potential to reduce patient side effects from high dose rate brachytherapy (HDR-BT). To efficiently deliver radiation to the prostate while minimizing trauma to sensitive structures such as the penile bulb, we modified the Acubot-RND 7-axis robot to guide insertion of diamond-tip needles into desired skew-line geometric arrangements. We extend and integrate two algorithms: Needle Planning with Integer Programming (NPIP) and Inverse Planning with Integer Programming (IPIP) to compute skew-line needle and dose plans. We performed three physical experiments with anatomically correct phantom models to study performance: two with the robot and one control experiment with an expert human physician (coauthor Hsu) without the robot. All were able to achieve needle arrangements that meet the RTOG-0321 clinical dose objectives with zero trauma to the penile bulb. We analyze systematic and random errors in needle placement; total RMS error for the robot system operating without feedback ranged from 2.6 to 4.3 mm, which is comparable to the RMS error of 2.7 mm obtained in an earlier study for PPI-BT treatment using a robot with 3D ultrasound feedback. © 2004-2012 IEEE.

High repeatability of needle insertion experiments is essential to the needle-phantom interaction model validation. However, the influential factors governing the accuracy of the phantom and needle deformations have not been systematically studied. In this paper, the impact of influential factors, including phantom characteristic represented by the ratio of DMSO and thawing time (TT), needle properties represented by needle external diameter (NED) and operating factors such as needle insertion velocity (IV), insertion positions (IP) and repeated insertion times (RITs) are analyzed by orthogonal experiment design. The range calculation shows the most sensitive parameters to phantom deformations are RITs, IV and DMSO while the most sensitive parameters to needle deflection are DMSO, TT and NED. By variance analysis, the significant factors on maximum tissue deformation (MTD) are IV, followed by RITs, DMSO and IP. And NED and TT have nearly no significant impact on MTD. The significant sequence on maximum needle deflection (MND) is as follows: DMSO, TT and NED. Results show that, among all impacting factors, phantom deformation is susceptible to both material properties and operative factors while the needle deflection is more susceptible to material properties of the phantom, which can help researchers in related fields to conduct experiments in a more precise manner and better understand the needle-phantom interaction mechanism. [ABSTRACT FROM AUTHOR]

Background: Needle insertions are painful, yet they are frequently performed for adults and children without using local anaesthetic (LA) to minimise pain and anxiety. Objectives: A hypothetical model was formulated to explore the factors related to Saudi nurses’ self-reported readiness to use LA prior to undertaking parenteral procedures in their workplaces. Design: This was an exploratory, cross-sectional study. Methods: Four hundred seventy-five nurses were recruited from one hospital in Saudi Arabia. We considered eighteen latent variables related to nurses’ attitudes and ability to pursue six roles associated with LA before needle procedures. A model was created to identify the staff attitudes and self-efficacy pathways influencing readiness to use LA. Results: The nurses' readiness to use LA before needle procedures was directly predicted by organisational factors (e.g., hospital policy, doctors' orders), procedural time constraints, underestimation of needle pain, patient characteristics and medical conditions, nurses’ knowledge and skills related to LA, and parenteral procedure practices. Conclusions: Nurses' readiness to use LA was influenced by their beliefs about certain aspects of their practice and the nature of patients’ presenting problems. Impact statement: Identifying factors that affect LA use helps us understand this issue and may assist policymakers in developing nursing practice.

Haptic feedback can be helpful for accurate needle insertion but is complicated by friction on the needle shaft. Concepts to directly measure the forces at the needle tip exist but cause additional cost and complexity. Moreover, haptic devices may show inaccuracies in recreating forces. We present a novel force feedback method that uses needle shaft forces and enhances haptic feedback of subsurfaces based on robotic ultrasound elastography. This approach allows to overcome accuracy limitations of haptic devices. We evaluate our method in a volunteer subject study using recordings from a robotic needle driver setup. We compare haptic feedback based on shaft and enhanced force for the detection of surfaces inside of gelatin phantoms. Using our method, the error of subsurface detection decreased from more than 16 to about 1.7 mm for the first subsurface. A second subsurface was solely detectable using our method with an error of only 1.4 mm. Insertion time decreased by more than 32%. The results indicate that our enhanced sensor is suitable to detect subsurfaces for untrained subjects using a haptic feedback device of limited accuracy.

Rotational needle insertion is commonly used in needle biopsy to improve cutting performance. The application of rotational motion for needle insertion has been shown to efficiently reduce the cutting force. However, studies have found that needle rotation can increase tissue damage due to the tissue winding effect. The bidirectional rotation of a needle during insertion can be a solution to avoid tissue winding while maintaining a low cutting force. In this study, needle insertion with bidirectional rotation was investigated by conducting mechanical and optical experiments. First, needle insertion tests were performed on gelatin-based tissue phantom samples to understand the effect of bidirectional needle rotation on the cutting force. Subsequently, the effective strain, which is an indicator of tissue damage, was observed at the cross-sections of samples in the axial and radial directions of the needle by using the digital image correlation (DIC) technology. The primary findings of this study are as follows: (1) higher needle insertion speeds result in higher cutting forces and effective strains that occur at the axial cross-section, (2) increase in the needle rotation reduces the cutting force and effective strain at the axial cross-section but increases the effective strain at the radial cross-section, (3) application of bidirectional rotation decreases the mean effective strain at the radial cross-section by 10%–25% while maintaining a low cutting force. In clinical applications, bidirectional rotation can be a useful strategy to simultaneously reduce the cutting force and tissue damage, which leads to better cutting performance and lower risks of bleeding and hematoma. [ABSTRACT FROM AUTHOR]

Penetration of a flexible and steerable needle into a soft target material is a complex problem to be modelled, involving several mechanical challenges. In the present paper, an adaptive finite element algorithm is developed to simulate the penetration of a steerable needle in brain-like gelatine material, where the penetration path is not predetermined. The geometry of the needle tip induces asymmetric tractions along the tool–substrate frictional interfaces, generating a bending action on the needle in addition to combined normal and shear loading in the region where fracture takes place during penetration. The fracture process is described by a cohesive zone model, and the direction of crack propagation is determined by the distribution of strain energy density in the tissue surrounding the tip. Simulation results of deep needle penetration for a programmable bevel-tip needle design, where steering can be controlled by changing the offset between interlocked needle segments, are mainly discussed in terms of penetration force versus displacement along with a detailed description of the needle tip trajectories. It is shown that such results are strongly dependent on the relative stiffness of needle and tissue and on the tip offset. The simulated relationship between programmable bevel offset and needle curvature is found to be approximately linear, confirming empirical results derived experimentally in a previous work. The proposed model enables a detailed analysis of the tool–tissue interactions during needle penetration, providing a reliable means to optimise the design of surgical catheters and aid pre-operative planning. [ABSTRACT FROM AUTHOR]