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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.

A thorough understanding of needle–tissue interaction mechanics is necessary to optimize needle design, achieve robotically needle steering, and establish surgical simulation system. It is obvious that the interaction is influenced by numerous variable parameters, which are divided into three categories: needle geometries, insertion methods, and tissue characteristics. A series of experiments are performed to explore the effect of influence factors (material samples n=5 for each factor) on the insertion force. Data were collected from different biological tissues and a special tissue-equivalent phantom with similar mechanical properties, using a 1-DOF mechanical testing system instrumented with a 6-DOF force/torque (F/T) sensor. The experimental results indicate that three basic phases (deformation, insertion, and extraction phase) are existent during needle penetration. Needle diameter (0.7–3.2mm), needle tip (blunt, diamond, conical, and beveled) and bevel angle (10–85°) are turned out to have a great influence on insertion force, so do the insertion velocity (0.5–10mm/s), drive mode (robot-assisted and hand-held), and the insertion process (interrupted and continuous). Different tissues such as skin, muscle, fat, liver capsule and vessel are proved to generate various force cures, which can contribute to the judgement of the needle position and provide efficient insertion strategy.

Autoinjector devices are rapidly becoming the preferred method of drug delivery for a wide array of pharmaceuticals such as monoclonal antibodies. Yet, our understanding of injection biomechanics is limited, but is crucially important to create autoinjectors that lead to the least amount of pain, penetrate the skin to a desired depth, produce small lesions that minimize back flow of drug, and operate robustly even given the variability in the skin mechanics among individuals. We propose a finite element model of needle insertion coupled to the dynamic model of an autoinjector. The finite element model is embedded with a cohesive zone plane to capture crack initiation and propagation within an energy-based fracture mechanics framework. The cohesive zone model is supported by experimental observations of a mode I crack during the needle insertion into the soft tissue. Model calibration against force curves from needle insertion experiments leads to estimated material and fracture properties that match values reported in independent experiments from the literature. With the calibrated model we explore the effect of change in the material properties and device parameters on the insertion dynamics. One of the most interesting findings is that pre-compression of skin from the autoinjector base plate can regulate the stress field near the skin surface and add strain energy that is available for crack formation.

Robot-assisted surgery is of growing interest in the surgical and engineering communities. The use of robots allows surgery to be performed with precision using smaller instruments and incisions, resulting in shorter healing times. However, using current technology, an operator cannot directly feel the operation because the surgeon-instrument and instrument-tissue interaction force feedbacks are lost during needle insertion. Advancements in force feedback and control not only help reduce tissue deformation and needle deflection but also provide the surgeon with better control over the surgical instruments. The goal of this review is to summarize the key components surrounding the force feedback and control during robot-assisted needle insertion. The literature search was conducted during the middle months of 2017 using mainstream academic search engines with a combination of keywords relevant to the field. In total, 166 articles with valuable contents were analyzed and grouped into five related topics. This survey systemically summarizes the state-of-the-art force control technologies for robot-assisted needle insertion, such as force modeling, measurement, the factors that influence the interaction force, parameter identification, and force control algorithms. All studies show force control is still at its initial stage. The influence factors, needle deflection or planning remain open for investigation in future.

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.

PurposeTo 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.MethodsThirty-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.ResultsOverall 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).ConclusionsAccurate 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.

Interventional radiologists mainly rely on visual feedback via imaging modalities to steer a needle toward a tumor during biopsy and ablation procedures. In the case of CT-guided procedures, there is a risk of exposure to hazardous X-ray-based ionizing radiation. Therefore, CT scans are usually not used continuously, which increases the chances of a misplacement of the needle and the need for reinsertion, leading to more tissue trauma. Interventionalists also encounter haptic feedback via needle–tissue interaction forces while steering a needle. These forces are useful but insufficient to clearly perceive and identify deep-tissue structures such as tumors. The objective of this paper was to investigate the effect of enhanced force feedback for sensing interaction forces and guiding the needle when applied individually and simultaneously during a virtual CT-guided needle insertion task. We also compared the enhanced haptic feedback to enhanced visual feedback. We hypothesized that enhancing the haptic feedback limits the time needed to reach the target accurately and reduces the number of CT scans, as the interventionalist depends more on real-time enhanced haptic feedback. To test the hypothesis, a simulation environment was developed to virtually steer a needle in five degrees of freedom (DoF) to reach a tumor target embedded in a liver model. Twelve participants performed in the experiment with different feedback conditions where we measured their performance in terms of the following: targeting accuracy, trajectory tracking, number of CT scans required, and the time needed to finish the task. The results suggest that the combination of enhanced haptic feedback for guidance and sensing needle–tissue interaction forces significantly reduce the number of scans and the duration required to finish the task by 32.1% and 46.9%, respectively, when compared to nonenhanced haptic feedback. The other feedback modalities significantly reduced the duration to finish the task by around 30% compared to nonenhanced haptic feedback.

Background and AimsA freely available visual guide with optimal angles for paramedian approaches, depending on the skin-dural sac distance (S-DS-d) (http://diposit.ub.edu/dspace/handle/2445/179594 ) and viable paths for needle insertions perpendicular to the back, below the upper spinous process in a given interspinous space, had been described. Our aim was to verify needle location applying the guide in ex-vivo samples.MethodsRandom selection of ex-vivo samples with flexed lumbosacral spines (n=7), determination of S-DS-d in the interspinous spaces by ultrasound, needle insertions at axial 0°, below the upper spinous process at different interspinous spaces, from L4-L5 to L1-L2 [n=42; median (n=21), 1cm paramedian (n=16) or individualized paramedian, previsualizing the longest interlaminar height, pre-estimating the angle by means of a protractor (n=5)], computed tomography, three-dimensional reconstruction and verification of needle location (figure 1).Abstract EP243 Figure 13D reconstruction of bone structures and needle positions in flexed spines of ex-vivo samplesAbstract EP243 Figure 2When osteoporotic vertebral compression fractures are present, the contact between adjacent spinal processes impedes the needle penetration in median approachesAbstract EP243 Figure 3Median and paramedian approaches at 0° regarding the axial plane, taking the upper spinous process as reference, lead to successful needle insertions within the spinal canal in non-fractured spinesResultsWhen osteoporotic compression fracture was found (38%), the contact between adjacent spinous process impeded the median approach (figure 2), but most needle insertions were located within the spinal canal in the other cases (85.7% median or 81% 1cm paramedian) (figure 3). In 23% the needle remained within the canal beside the dural sac. In 13% a certain bone penetration occurred. Individualization of the paramedian approach led to successful insertions at very variable angles and distances (up to 32,2° and 2,64 cm paramedian, respectively).ConclusionsUltrasound may indicate if the interspinous space is visible. Then, the insertion of needles at 0° regarding the axial plane, taking the upper process as reference, is viable. If not, the alternative optimal paramedian approach must be individualized in fractured or rotated spines.

Numerous research groups in the past have designed and developed robotic needle guide systems that improve the targeting accuracy and precision by either providing a physical guidance for manual insertion or enabling a complete automated intervention. Here we review systems that have been reported in the last 11 years and limited to straight line needle interventions. Most systems fall under the category of image guided systems as they either use magnetic resonance image, computed tomography, ultrasound or a combination of these modalities for real time image feedback of the intervention path being followed. Actuation and control technology along with materials used for construction are the main aspects that differentiate these systems from each other and have been reviewed here. Image compatibility test details and results are also reviewed as they are used to ensure proper functioning of these systems under the respective imaging environments. We have also reviewed needle guide systems which either don’t use any image feedback or have not reported any but provide physical guidance. Throughout this paper, we provide a comprehensive review of the technological aspects and trends in the field of robotic, straight line, needle guide intervention systems.

PurposeHollow-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.MethodsNeedle 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.ResultsAccording 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.ConclusionIn 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.