Deflection Of Needle Research Articles

Deflection of Needles, Used for Local Anesthesia in the Dental Practice – Comparative Study

The mandibular nerve blocks prove to be one of the most challenging anesthetic techniques for the dental practitioner. Many factors have a role in the success of these nerve blocks and one of them is the accuracy of the deposition of the anesthetic which can be influenced to a certain degree by the deflection of the injection needle. In this study, three types of injection needles (Septoject XL 30G, Septoject XL 27G and Medoject 23G) were tested for deflection in a reversible hydrocolloid (agar-agar). They were divided into three groups of 30 needles each and were all inserted in the agar-agar at a depth of 20 mm with the help of a dental surveyor. Two mutually perpendicular radiographs were made for each needle in order to calculate the deviation in mm. The results were analyzed and showed that the mean deflection in the 30G needles group was 5.32±1.91 mm, the deviation in the 27G group – 3.37±0.67 mm and none of the needles in the 23G group showed a deviation upon insertion in the hydrocolloid. The results in this study showed that dentists should always prefer needles with a smaller gauge, because they provide smaller deflection figures and therefore better accuracy in the deposition of the anesthetic.

A mechanics-based model for a tendon-driven active needle navigating inside a multiple-layer tissue.

Percutaneous minimally invasive procedures such brachytherapy and biopsy require a flexible active needle for precise movement inside tissue and accurate placement at target positions for higher success rates for diagnosis and treatment, respectively. In a previous work, we presented a tendon-driven active needle to navigate inside tissue. This work presents a new model to predict the deflection of the tendon-driven needle while steering in a multiple-layer soft tissue. A multi-layer phantom tissue with different localized stiffness was developed for needle insertion tests followed by indentation tests to identify its mechanical properties. Using a robot that inserts and actively bends the tendon-driven needle inside the soft tissue while simultaneously tracking the needle through ultrasound imaging, various experiments were conducted for model validation. The proposed model was verified by comparing the simulation results to the empirical data. The results demonstrated the accuracy of the model in predicting the tendon-driven needle deflection in multiple-layer (different stiffness) soft tissue.

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.

Pre-Operative Motion Planner for Steerable Needles Using Cost Map Based on Repulsive Field and Empirical Model of Needle Deflection

Abstract Needle insertion is a common procedure in percutaneous puncture. A motion planner for a steerable needle that considers the risk level of the path in anatomical environment and the actual deflection of clinical needle is necessary. A novel pre-operative motion planner for a steerable needle controlled by robot is proposed. Our method utilizes sampling-based planner to compute candidate path in the reachable region, and the path solutions are optimized by calculating the cost of a path based on a cost map. The cost map, which is built based on repulsive field theory from CT image, encodes the information of the obstacle locations and the criticality of the anatomical environment. The empirical formula that can predict needle trajectory is obtained by insertion experiments. Experiments show that under the guidance of our planner, the positioning error in phantom made with gelatin and three-dimensional (3D) printed models is less than 1.1 mm. Comparing with the straight-line insertion method in the same phantom, the positioning error was reduced by 80%. The results indicate that the motion planner has the potential to provide effective guidance for robot-assisted puncture surgery while enhancing the position precision and patient safety.

3D model of deflection of an asymmetrical needle during motion in soft tissues

This study describes a mathematical model of deflection of a steel medical injection needle during its motion in the soft tissue phantom (imitation of human tissues). This model is necessary for adjustment of robotically assisted systems during brachytherapy procedures or similar operations where high precision needle tip positioning is prerequisite. Since the needle tip is asymmetrical, the needle will deform when moving in human tissues and consequently deflect from the rectirectilinear motion. Thus, by inserting and rotating the needle around its axis the needle tip can be led along the predetermined path. This study adopts a new approach to describe an external impact on the needle when it moves inside human tissues and also describes 2D and 3D models, a process of selection of coefficients for 3D models, and provides simulation results.

Study on the Control Method and Optimization Experiment of Prostate Soft Tissue Puncture

In the treatment of prostate cancer patients, surgery of radioactive seed implantation with the puncture robots is an effective treatment method. However, when the puncture needle enters the lesion tissue, there are complicated forces between the needle body and the soft tissue, which leads to the drift of the prostate and the deflection of the puncture needle, thereby affecting the puncture accuracy. In order to improve the positioning accuracy and ensure the best treatment effect, a sine rotation continuous puncture control method was proposed in this paper. First, by analyzing the interaction between the puncture needle and the soft tissue, the force balance equation and the deflection equation were established, according to the equations, it could be known that puncture friction is the main factor affecting the deflection of the puncture needle. Second, combined with the influence of puncture friction and the research on the theory of rotation puncture, the sine rotation puncture method was compared with the direct puncture method and the existing rotation puncture method; Observed with a 4D Color Doppler Ultrasound to verify the feasibility of the rotating puncture theory and the effectiveness of the sine rotation puncture method. Third, through the establishment of Euler Beam model, rotation angle analysis and puncture velocity test analysis, the influence of dynamic parameters of this method on the puncture accuracy was discussed, the optimization range of each factor was obtained; The experiment was designed by the quadratic regression orthogonal combination theory, the experiment process was observed and recorded by a 3D X-ray scanner, the regression equations were established between experiment factors and experiment indicators with the Design-Expert, and the best parameter combinations were acquired through optimization. Last, comparison tests and verification test were carried out to verify the rationality and reliability of the optimized sine rotation puncture control method.

Simulation of Coupling Process of Flexible Needle Insertion into Soft Tissue Based on ABAQUS

In order to get to the desired target inside the body, it is essential to investigate the needle-tissue coupling process and calculate the tissue deformation. A cantilever beam model is presented to predicting the deflection and bending angle of flexible needle by analyzing the distribution of the force on needle shaft during the procedure of needle insertion into soft tissue. Furthermore, a finite element (FE) coupling model is proposed to simulate the needle-tissue interactive process. The plane and spatial models are created to relate the needle and tissue nodes. Combined with the cantilever beam model and the finite element needle-tissue coupling model, the simulation of needle-tissue interaction was carried out by the ABAQUS software. The comparing experiments are designed to understand the needle-tissue interactions, by which the same points in the experiments and simulation are compared and analyzed. The results show that the displacements in x and z directions in the simulation can accord with the experiments, and the deformation inside the tissue mainly occurs in the axial direction. The study is beneficial to the robotassisted and virtual needle insertion procedure, and to help the physicians to predict the inside tissue deformation during the treatments.

3D Manipulation of an Active Steerable Needle via Actuation of Multiple SMA Wires

SummaryMany medical procedures such as brachytherapy, thermal ablations, and biopsies are performed using needle-based procedures. In this work, 3D manipulation of an active needle realized by multiple Shape Memory Alloy (SMA) actuators was first predicted by Finite Element Analyses (FEA), and then demonstrated by a fabricate prototype. The FEA results were validated by planar deflection of an active needle. A similar FEA was developed to predict 3D manipulation of the active needle. For 17-gage needle, a maximum of 26° reversible deflection was achieved in 3D space via actuation forces of a 0.127 mm SMA wire. A scaled prototype was also developed and tested to show the feasibility of developing a 3D steering active needle with multiple actuators.

Cyclic Motion Control for Programmable Bevel-Tip Needles to Reduce Tissue Deformation

Robotic-assisted steered needles aim to accurately control the deflection of the flexible needle’s tip to achieve accurate path following. In doing so, they can decrease trauma to the patient, by avoiding sensitive regions while increasing placement accuracy. This class of needle presents more complicated kinematics compared to straight needles, which can be exploited to produce specific motion profiles via careful controller design and tuning. Motion profiles can be optimized to minimize certain conditions such as maximum tissue deformation and target migration, which was the goal of the formalized cyclic, low-level controller for a Programmable Bevel-tip Needle (PBN) presented in this work. PBNs are composed of a number of interlocked segments that are able to slide with respect to one another. Producing a controlled, desired offset of the tip geometry leads to the corresponding desired curvature of the PBN, and hence desired path trajectory of the system. Here, we propose a cyclical actuation strategy, where the tip configuration is achieved over a number of reciprocal motion cycles, which we hypothesize will reduce tissue deformation during the insertion process. A series of in vitro, planar needle insertion experiments are performed in order to compare the cyclic controller performance with the previously used direct push controller, in terms of targeting accuracy and tissue deformation. It is found that there is no significant difference between the target tracking performance of the controllers, but a significant decrease in axial tissue deformation when using the cyclic controller.

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 150mm 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.

Comparison of Spinal Needle Deflection in a Ballistic Gel Model.

BackgroundPercutaneous diagnostic and therapeutic procedures are commonly used in the treatment of spinal pain. The success of these procedures depends on the accuracy of needle placement, which is influenced by needle size and shape.ObjectivesThe purpose of this study is to examine and quantify the deviation of commonly used spinal needles based on needle tip design and gauge, using a ballistic gel tissue simulant.Materials and MethodsSix needles commonly used in spinal procedures (Quincke, Short Bevel, Chiba, Tuohy, Hustead, Whitacre) were selected for use in this study. Ballistic gel samples were made in molds of two depths, 40mm and 80 mm. Each needle was mounted in a drill press to ensure an accurate needle trajectory. Distance of deflection was recorded for each needle.ResultsIn comparing the mean deflection of 22 gauge needles of all types at 80 mm of depth, deflection was greatest among beveled needles [Short Bevel (9.96 ± 0.77 mm), Quincke (8.89 ± 0.17 mm), Chiba (7.71 ± 1.16 mm)], moderate among epidural needles [Tuohy (7.64 ± 0.16 mm) and least among the pencil-point needles [Whitacre (0.73 ± 0.34 mm)]. Increased gauge (25 g) led to a significant increase in deflection among beveled needles. The direction of deflection was away from the bevel with Quincke, Chiba and Short Beveled needles and toward the bevel of the Tuohy and Hustead needles. Deflection of the Whitacre pencil-point needle was minimal.ConclusionsThere is clinical utility in knowing the relative deflection of various needle tips. When a procedure requires a needle to be steered around obstacles, or along non-collinear targets, the predictable and large amount of deflection obtained through use of a beveled spinal needle may prove beneficial.

Estimating needle tip deflection in biological tissue from a single transverse ultrasound image: application to brachytherapy.

This paper proposes a method to predict the deflection of a flexible needle inserted into soft tissue based on the observation of deflection at a single point along the needle shaft. We model the needle-tissue as a discretized structure composed of several virtual, weightless, rigid links connected by virtual helical springs whose stiffness coefficient is found using a pattern search algorithm that only requires the force applied at the needle tip during insertion and the needle deflection measured at an arbitrary insertion depth. Needle tip deflections can then be predicted for different insertion depths. Verification of the proposed method in synthetic and biological tissue shows a deflection estimation error of [Formula: see text]2mm for images acquired at 35% or more of the maximum insertion depth, and decreases to 1mm for images acquired closer to the final insertion depth. We also demonstrate the utility of the model for prostate brachytherapy, where in vivo needle deflection measurements obtained during early stages of insertion are used to predict the needle deflection further along the insertion process. The method can predict needle deflection based on the observation of deflection at a single point. The ultrasound probe can be maintained at the same position during insertion of the needle, which avoids complications of tissue deformation caused by the motion of the ultrasound probe.

V3-01 USE OF THE OHMMETER TO IDENTIFY THE SITE OF FLUID LEAK DURING ARTIFICIAL URINARY SPHINCTER REVISION SURGERY

You have accessJournal of UrologyMale Voiding/Sexual Dysfunction/BPH/ Incontinence/Infection/Infertility1 Apr 2015V3-01 USE OF THE OHMMETER TO IDENTIFY THE SITE OF FLUID LEAK DURING ARTIFICIAL URINARY SPHINCTER REVISION SURGERY Michael Belsante, John Patrick Selph, Jessica Lloyd, Divya Ajay, George Webster, Ngoc-Bich Le, and Andrew Peterson Michael BelsanteMichael Belsante More articles by this author , John Patrick SelphJohn Patrick Selph More articles by this author , Jessica LloydJessica Lloyd More articles by this author , Divya AjayDivya Ajay More articles by this author , George WebsterGeorge Webster More articles by this author , Ngoc-Bich LeNgoc-Bich Le More articles by this author , and Andrew PetersonAndrew Peterson More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.1342AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Revision surgery for the malfunctioning artificial urinary sphincter (AUS) is necessary in up to 44% of patients and is a frustrating problem for patient and physician alike. Many techniques and algorithms have been described for troubleshooting the malfunctioning AUS, the etiology of which can include mechanical failure, urethral erosion, sub-cuff atrophy, and fluid leak from the device. Difficulty identifying the site of fluid leak leads many implanters to simply replace the device in its entirety. We have found the use of an ohmmeter to be consistently helpful in the identification and localization of the site of leakage from individual components of the AUS allowing for removal and replacement of individual AUS components. METHODS The right lower quadrant incision site overlying the AUS tubing with connectors is opened and the tubing and connectors are identified and dissected. Rubber shod clamps are placed on the tubing on either side of the connectors on both the cuff and pressure regulating balloon (PRB) tubing. The tubing is cut. Fluid is aspirated from the balloon to confirm fluid loss. At this point, fluid is injected into the PRB and the ohmmeter leads are applied to the injection needle and the metal skin retractor (ground). Deflection of the ohmmeter needle indicates flow of fluid and identifies a leak in the PRB. This is repeated with the tube to the AUS pump as well as the cuff. Components that demonstrate a leak are replaced. A leak in the affected component is then confirmed on the back table. The device is reconnected and cycled under cystoscopic vision. RESULTS Intraoperative use of the ohmmeter has been used in 19 cases on 18 patients. Correct identification of the leak site was achieved in 18/19 patients (94.7%). In the one unsuccessful case, the entire device was removed and replaced. All 18 cases had satisfactory outcomes with no patients requiring further revision surgery for leakage. Four patients required subsequent cuff downsizing for sub-cuff atrophy at a median 19 months after initial revision surgery. CONCLUSIONS Our technique for identifying and localizing a fluid leak is highly reproducible and successful and has allowed for precise management of patients with AUS malfunction due to fluid loss. © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e335 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Michael Belsante More articles by this author John Patrick Selph More articles by this author Jessica Lloyd More articles by this author Divya Ajay More articles by this author George Webster More articles by this author Ngoc-Bich Le More articles by this author Andrew Peterson More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Needle Deflection during Insertion into Soft Tissue Based on Virtual Spring Model

Needle insertion is the most common procedure of minimally invasive interventions. During insertion into a soft tissue, the needle with bevel tip can deflect due to the asymmetric forces acting on the tip of the needle. In this paper, a mechanics-based model is developed to predict the needle deflection. In the model, the needle is considered as a cantilever beam supported by a series of nonlinear springs each of which has stiffness different from each other. The value of stiffness can be calculated by cutting force acting on the needle tip. Based on the model and the analysis of cutting force and friction force, Rayleigh-Ritz method is used to estimate the amount of needle deflection. Experiment shows that the simulation model can accurately predict the deflection of the bevel-tipped needle.

MECHANICS-BASED BEVEL-TIP NEEDLE DEFLECTION MODEL DURING NEEDLE–SOFT TISSUE INTERACTION PROCESS

Flexible needle insertion is performed in many clinical and brachytherapy procedures. Needle bending which results from needle–tissue interaction and needle flexibility plays a pivotal role in implantation accuracy. In this paper, a needle insertion force model and a mechanics-based needle deflection model are applied in simulating the real needle insertion process. Using tissue-equivalent materials, the needle force model is acquired from needle insertion experiments. Based on the principle of minimum potential energy, a mechanics-based model is developed to calculate needle deflection. The needle deflection model incorporates needle insertion forces model, needle–tissue interaction model, needle geometric, and tissue properties. The bending–stretching coupling and geometric non-linearity of the flexible needle are both taken into consideration in the needle deflection model. A modified p–y curves method is first introduced in depicting the lateral needle–tissue interaction. The comparison between experimental and simulation results of needle deflection shows that our mechanics-based model can simulate the deflection of the flexible needle with reasonable accuracy. Parametric studies on different geometry properties of needles show that our mechanics-based model can precisely predict the needle deflection when more than one parameter is changed. In addition, as the needle deflection results are obtained numerically by Rayleigh–Ritz approach, further study on the form of deflection formulation leads to the conclusion that choosing a higher order polynomial can improve the overall simulation accuracy.

A Modeling of the Deflection of Compass Needle near by Wire Carrying an Electric Current and its Theoretical Study

A Modeling of the Deflection of Compass Needle near by Wire Carrying an Electric Current and its Theoretical Study

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).

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.

On Nonexistence of Magnetic Monopoles: Deflection of Magnetic Needle in Static Electric Field of Electric Dipole Implies No Magnetic Field in the Universe

Motion of electrical charged particle in static curled electric field is studied. The electric field exerts asymmetric electric force which forces the particle to follow a curved path. Like in magnetic fields, the path is determined by instantaneous velocity of the particle and the field properties. This way, it shows a resemblance between the asymmetric electric force exerted in static curled electric field and the formal magnetic force exerted in static magnetic field. This resemblance permits to deflect a magnetic needle in static electric field, having non-zero curl, of an electric dipole. It implies the true nature of static magnetic force is static asymmetric electric force and the true nature of static magnetic field is static curled electric field. It provides answer to the question, why the magnetic monopoles are absent in the universe.

Needle‐through‐Quincke needle technique for establishing spinal anaesthesia in the obese patient

We would like to report a novel needle-through-Quincke needle technique for assisting the establishment of spinal anaesthesia in the obese patient that two of the authors have used as their standard for obese patients in obstetric and orthopaedic settings for several years. Difficulties in successfully establishing subarachnoid anaesthesia often occur with obese patients and these can be further compounded during pregnancy by additional weight gain, oedema and problems with optimal positioning. The use of ultrasound to localise the spinal anatomy, including location of the interspinous spaces and the depth of the epidural space, has been well documented [1, 2], as has the use of an epidural needle as an introducer for long spinal needles [3]. We use ultrasound to locate a suitable space and to measure the depth of the dura. We mark the space as a needle insertion point. We then insert a 9-cm 20-G Quincke spinal needle (Becton Dickinson, Franklin Lakes, NJ, USA) through the marked point to a depth some 2–3 cm short of the dura, as measured by ultrasound. We then pass a 12-cm 24-G Sprotte needle (Pajunk, Geisingen, Germany), through the ligamentum flavum and dura into the cerebrospinal fluid (CSF). Should CSF not be visible within the Sprotte needle, we advance both needles together until successful dural puncture occurs. Should ultrasound be unavailable or unhelpful in identifying the space, we employ a blind approach. We insert the Quincke needle into the interspinous ligaments and then pass the long Sprotte needle through the Quincke needle, to project beyond the end of the latter. We can then advance the two needles together, with the atraumatic tip of the Sprotte needle acting as the leading point. We believe our technique avoids some of the potential problems of using a Tuohy needle as a spinal introducer, in particular, the inability to pass the spinal needle through the Huber tip, the deflection of the spinal needle by the Huber tip, the ‘dry tap’ that can occur after successful localisation of the epidural space [4], and a significantly smaller breech to the dura should accidental puncture occur with the Quincke needle. Dural puncture is extremely unlikely, as the leading point is that of the Sprotte needle. The Quincke needle is sufficiently stiff to allow easy placement even in very obese patients. We believe that ultrasound localisation adds to the accuracy of the technique, by providing accurate anatomical information of depth and the required angle of needle insertion. No external funding and no competing interests declared.