Needle Design Research Articles

A proof-of-concept study of a prototype needle that mitigates intraocular pressure rise following intravitreal injection

PurposeTo determine the feasibility of a prototype needle that enhances vitreous reflux (VR) to control intraocular pressure (IOP) in intravitreal injection (IVI).MethodsWe created an eye model to compare IVI using a standard 30-G needle with four different versions of a 30-G prototype needle with one to four surface grooves that enhanced VR. We injected 50, 70, and 100 µl saline through porcine sclera or 460-µm-thick rubber and measured the peak and 3-second pressure before we extracted the needle and measured the 10-second pressure.Results50-µl injection through sclera with the standard needle resulted in mean (SD) pressure of 58.6 (3.8) mmHg at peak, 52.8 (4.7) mmHg at 3 s, and 39.6 (18.0) mmHg at 10 s. The prototype needle lowered the pressure; four grooves resulted in mean (SD) pressure of 29.4 (5.6) mmHg at peak, 22.0 (3.7) mmHg at 3 s, and 7.2 (6.6) mmHg at 10 s. 70-µl and 100-µl injections through sclera with the standard needle resulted in mean (SD) pressure of 68.8 (3.6) and 86.0 (6.0) mmHg at peak. Similar to 50-µl injection, the prototype needle lowered the pressure for 70-µl and 100-µl injections. At 10 s, we observed varying leakage at the injection site for sclera but not for rubber.ConclusionsThe study provides proof of concept for a needle design for which surface grooves enhance VR and counteract the effect of IVI on IOP. The safety and efficacy of the prototype needle must be studied further in a clinical trial.

Impact of Needle Design and Suture Gauge on Tissue Tearing During Skin Suturing: A Comparative Analysis.

Surgeons face numerous choices in selecting sutures for skin closure, with potential adverse effects such as tissue tearing. To investigate the influence of needle design and suture gauge on tissue tearing during suturing procedures. The authors tested the tear-through force in Newtons for 3 needle types and 3 suture gauges using an artificial skin model and a professional-grade tensiometer. Suture material was secured into the skin model, and force was applied to the suture at a constant rate, resulting in tearing. Force-displacement and force-time curves were generated. Evaluation included conventional cutting (PC-3), reverse cutting (PS-3), and taper point (BB) needles with a 5-0 polypropylene suture. In addition, nylon sutures with a reverse cutting needle (PS-2) were tested at 3 suture gauges (5-0, 4-0, 3-0). The mean tear-through forces for PC-3, PS-3, and BB were 3.26 N, 3.75 N, and 4.07 N, respectively. For the 5-0, 4-0, and 3-0 nylon sutures, the mean tear-through forces were 3.44 N, 3.81 N, and 4.04 N, respectively. Statistical analysis revealed a significant impact of suture gauge size (p < .001) and needle geometry (p < .001) on tear-through force. Larger suture diameter and taper needles minimize tissue tearing.

Optimizing Solid Microneedle Design: A Comprehensive ML-Augmented DOE Approach.

Microneedles (MNs), that is, a matrix of micrometer-scale needles, have diverse applications in drug delivery, skincare therapy, and health monitoring. MNs offer a minimally invasive alternative to hypodermic needles, characterized by rapid and painless procedures, cost-effective fabrication methods, and reduced tissue damage. This study explores four MN designs, cone-shaped, tapered cone-shaped, pyramidal with a square base, and pyramidal with a triangular-shaped base, and their optimization based on predefined criteria. The workflow encompasses three loading conditions: compressive load during insertion, critical buckling load, and bending loading resulting from incorrect insertion. Geometric parameters such as base radius/width, tip radius/width, height, and tapered angle tip influence the output criteria, namely, total deformation, critical buckling loads, factor of safety (FOS), and bending stress. The comprehensive framework employing a design of experiment approach within the ANSYS workbench toolbox establishes a mathematical model and a response surface fitting model. The resulting regression model, sensitivity chart, and response curve are used to create a multiobjective optimization problem that helps achieve an optimized MN geometrical design across the introduced four shapes, integrating machine learning (ML) techniques. This study contributes valuable insights into a potential ML-augmented optimization framework for MNs via needle designs to stay durable for various physiologically relevant conditions.

The effects of aperture position and length in side-vented needles on root canal irrigation: A computational fluid dynamics study

IntroductionRoot canal irrigation is crucial for infection control during root canal treatment. Side-vented needles for positive pressure irrigation are commonly used in clinical practice. However, variations in needle design among manufacturers can impact the fluid dynamics of irrigation. This study aims to use computational fluid dynamics to explore the flow characteristics of different needle aperture lengths and positions, and their effects on the effectiveness and safety of irrigation, using a validated passive scalar transport numerical model. MethodsThe validation of the CFD irrigant model was achieved by comparing it with an in vitro irrigation experiment model. The CFD model used scalar concentration, while the in vitro experiment model used red dye tracing. Using a standard 30G side-vented needle as a reference, virtual needle models featuring four aperture lengths and three positions were created. These virtual irrigation needles were then placed in two root canal geometries for CFD simulation to evaluate fluid exchange capabilities and related fluid dynamic parameters. ResultsThe results of the CFD simulation, using a scalar transport model, closely matched the in vitro tracer tests for irrigation experiments across seven root canal geometries. The CFD analysis indicated that positioning the aperture lower increased the irrigant exchange distance. Notably, decreasing the aperture length to 0.25x, and positioning it at the lower end of the needle significantly increased exchange distance and shear stress, while reducing apical pressure. ConclusionsThese results indicate that the position and length of the aperture affect the exchange distance of irrigant flow, wall shear stress, and apical pressure. The CFD validation model for scalar transport, based on a steady state, can function as a valuable tool for optimizing the side-vented needle in research. Further research on the design of side-vented needles will enhance the understanding of flow characteristics beneficial for irrigation efficiency in clinical practice.

Effects of the Irrigation Needle Design on Root Canal Disinfection and Cleaning

IntroductionThis ex vivo study evaluated the disinfecting and cleaning effects of root canal preparation using sodium hypochlorite irrigation with 3 different needle designs. MethodsMesial roots from extracted mandibular molars with Vertucci class II configuration were anatomically matched based on micro-computed tomography (micro-CT) analyses and distributed into 3 groups (n = 18/group). The canals were contaminated with a mixed bacterial culture for 30 days and then subjected to preparation using 2.5% sodium hypochlorite irrigation with open-ended flat needle (3 mm short of the working length - WL), closed-ended side-vented irrigation needle (1 mm short of the WL), or a closed-ended plastic needle with 2 lateral outlets (TruNatomy) (1 mm short of the WL). Bacteriological samples were taken from the canals before (S1) and after preparation (S2). After another micro-CT scan, the roots were sectioned and samples were also taken from the apical canal segment (S3). Bacterial reduction was assessed by quantitative real-time polymerase chain reaction. The amount of accumulated hard tissue debris was evaluated by micro-CT. ResultsA substantial reduction in bacterial counts was observed in all 3 groups when comparing S1 with S2 (99.95%, 98.93%, and 98.90% in the open-ended, closed-ended, and TruNatomy needle groups, respectively) (P < .01). No significant differences were observed between groups for bacterial reduction in the full and apical canal (P > .05). There were no intergroup differences in the amount of accumulated hard tissue debris either (P > .05). The open-ended needle group showed significantly more specimens with quantitative real-time polymerase chain reaction negative results for bacteria in S3 than TruNatomy (P < .05). ConclusionWhen used up to an appropriate insertion depth, the 3 needle types result in similar antibacterial and cleaning performance, provided variables such as needle size and irrigant type, volume and flow rate are controlled. Exclusive analysis of the apical segment, including the isthmus, revealed that the open-ended needle yielded more cases negative for bacteria.

Experimental investigation of a transcritical CO2 refrigeration system incorporating rotary gas pressure exchanger and low lift ejectors

Natural refrigerants like CO2 are playing a significant role in making refrigeration and heat pump systems climate-friendly by slowly phasing out the high global warming refrigerants like hydrofluorocarbons (HFCs). However, the efficiency of a transcritical CO2 refrigeration system declines significantly when the ambient temperature increases, primarily attributed to the high-pressure lift and the losses incurred during expansion. To remedy this issue, this paper presents a novel rotary gas pressure exchanger (PXG) device, which simultaneously achieves high differential pressure expansion work recovery and the “free compression” of the portion of the flash gas in a compact, rotary machine. For this, a PXG device is designed, fabricated, and tested to achieve free compression of CO2 over the entire differential pressure of approximately 70 bar between a receiver and a gas cooler. This is one of the highest free-pressure lift provided by any device to date in CO2 refrigeration. However, there is a small pressure loss of approximately 1–2 bar in the system due to viscous and inertia losses in the piping and in the PXG itself, which needs to be overcome by an external booster device. Results on a baseline PXG integrated system with two low lift booster compressors are presented, which show up to 60 bar free pressure lift and up to 18.2 % COP improvement provided by PXG. Additionally, key performance characteristics of the PXG, like the expansion work recovery, the mass boost ratio, direct fluid-to-fluid contact, and no pass-through operation are experimentally quantified. This work also presents a novel method to integrate two low lift ejectors with PXG to eliminate the need for separate low lift compressors. The low lift ejectors are designed, fabricated, and tested in-house, followed by their integration with the PXG device. A new type of transcritical CO2 refrigeration system is designed to integrate these low lift ejectors with PXG, and experiments are conducted at various evaporator thermal duties and gas cooler exit temperatures, simulating varying ambient temperature conditions. A novel control system to control the gas cooler pressure to optimal thermodynamic levels using PXG rotational speed is demonstrated experimentally. Further, automated control of high-pressure low lift ejector mass flow using an in-built needle design has been successfully demonstrated to optimise PXG mass boost performance. The LP low lift ejector achieved a successful pressure lift of 3.8 bar, and the HP low lift ejector showed a lift of 5.7 bar on the top of 42 bar free pressure lift provided by PXG for up to 5.8 kg/min mass flow delivered by free PXG compression. The results from this study demonstrate that the PXG device provides a significant energy efficiency improvement to the transcritical CO2 refrigeration system, and the novel low lift ejectors, when integrated with PXG, provide a successful method to maximise PXG’s thermodynamic potential.

3D‐Printed Hollow Microneedles Array with Luer Lock Connection for Facile and Painless Intradermal Injection: A Proof of Concept

AbstractA 3D‐printed array of hollow microneedles (HMNs) is designed and fabricated using a high‐resolution stereolithography 3D printer and assembled with a 3D‐printed reservoir that incorporates a Luer lock mechanism, ensuring standard and secure connection to syringes. The proof‐of‐concept needle designs consist of half‐eccentric and concentric conical tip shapes, each arrayed with two different interspacing values. After the geometrical features of the devices are characterized, the devices are tested ex vivo in porcine skin to evaluate the impact of tip shape and interspacing on the depth of penetration and the efficacy of the devices in delivering fluids (such as tattoo ink) into the dermis. Overall, the 3D‐printed HMNs can deliver fluids into the target layer of skin. Refinement of the design is ongoing with the ultimate aim to provide alternatives for intradermal drug delivery and diagnostic imaging, such as superficial lymphography.

Design and experiment of a single needle vibrating pneumatic pepper precision seed dispenser

Design and experiment of a single needle vibrating pneumatic pepper precision seed dispenser

Irrigant dynamics of a back-to-back double side-vented needle in root canals with various tapers: a computational fluid dynamics study

Understanding the apical pressure and irrigant flow patterns in root canals is crucial for safe and effective irrigation. Therefore, this study aimed to assess the flow characteristics of irrigants in root canal models with varying tapers during final irrigation by employing various needle designs, including a back-to-back double-side-vented needle, through computational fluid dynamics. The root canal model was configured as a closed geometrical cone with a simulated apical zone (size 30) and features tapers of 4%, 6%, and 8%. Three needle types—open-ended needle (OEN), single side-vented needle (SSVN), and double side-vented needle (DSVN)—were investigated. The results indicated that for the 4% taper models, the open-ended needle generated the maximum apical pressure, followed by the double side-vented needle and the single side-vented needle. However, in the 6% and 8% tapering root canal models, the double-side-vented needle applied the lowest maximum apical pressure. Consequently, the DSVN can pose a risk for irrigant extrusion in minimally prepared canals due to heightened apical pressure. In wider canals, the DSVN exhibited lower apical pressure. The maximum irrigant replacement was observed with OEN compared to that of the closed-ended group for both flow rates. Additionally, compared with OENs, closed-ended needles exhibited nonuniform and lower shear wall stress.

The effect of needle type (25 G Sprotte vs. Quincke) in spinal anesthesia on the incidence of transient neurologic syndrome: A randomized clinical trial.

Transient neurologic syndrome (TNS) is a postoperative pain in the back and buttock that can occur after spinal anesthesia. The spinal needle design may have an impact on the occurrence of TNS. We decided to compare the incidence of TNS and related factors between two spinal needle types. In this randomized clinical trial, 150 patients aged 18-60 years and American Society of Anesthesiologists (ASA) physical status I who underwent lower abdomen or lower extremity surgeries with spinal anesthesia and supine position were enrolled. They were randomly divided into two groups (25 G Quincke or Sprotte needle) with 0.5% bupivacaine (12.5 mg). After the operation, the patients were asked to report any pain in the lower back, buttock, and thigh areas. A Visual Analog Scale (VAS) was also used to record the severity of the pain. Overall, 45 patients developed TNS. Twenty-nine patients in the Sprotte group (38.7%) and 16 patients in the Quincke group (21.3%) developed TNS (p = 0.75). More patients in the Sprotte group (25.3%) had severe pain (VAS score of 8-10) when compared with the Quincke group (6.7%). There was no significant difference in TNS symptoms duration between the two groups. In about half of patients (51.9%) in the Sprotte group and 57.3% of patients in the Quincke group, the symptoms resolved after 2-3 h. Although the incidence of TNS did not differ significantly, patients for whom a Sprotte spinal needle had been used had more severe pain. This suggests that the Quincke needle caused less severe pain.

Research on product design of FAHP bone marrow aspiration needle

Bone marrow aspiration is a crucial medical procedure to obtain bone marrow samples for diagnosis and treatment. However, traditional bone marrow aspiration needles face several challenges such as operational difficulties, inadequate sample acquisition, and patient discomfort. To address these issues, we aimed to design a bone marrow aspiration needle product by using fuzzy analytic hierarchical process (FAHP). The FAHP method was used to identify key factors in the design of the bone marrow aspiration needle, including technicality, usage, and application characteristics. The importance weights and priorities of each factor were determined through questionnaires and interviews with experts. A new bone marrow aspiration needle product was developed based on the results of the FAHP. The new product design considers the weights and priorities assigned to key factors, resulting in improved convenience during operation and a higher success rate of sample acquisition. This was achieved by optimising the structure and material selection of the needle. This study presents a novel bone marrow puncture needle product that effectively integrates the importance and priority of the key factors. It successfully enhances operational performance and patient experience, thereby offering an innovative solution to improve the success rate and therapeutic effect of bone marrow punctures.

The bevel effect: a prospective, randomized investigation into needle design in dental intraligamentary anesthesia.

This in vivo study aimed to assess the impact of needle bevel design on puncture pain, anesthetic success, and mechanical deformations in intraligamentary injection (ILA) cases, comparing a short triple facet cut (STF) to a triple lancet cut (TL) after single or repetitive use. In a prospective single-blind trial, 200 ILA needles (STF, n = 100; TL, n = 100) were randomly assigned for dental procedures. Patients received ILA either with STF or TL needles, used once (group A; n = 50 each) or repeatedly (group B; n = 50). Puncture pain was assessed using a numerical rating scale (NRS). Anesthetic success was determined via cold spray (yes/no), and scanning electron microscopy (SEM) analyzed needle tip deformations. Puncture pain did not significantly differ between STF and TL, regardless of needle use or injection area. Success rates were comparable in single use (82% STF vs. 79% TL; p > 0.05). For repetitive use, STF exhibited a significantly higher success rate (80% vs. 69%; p = 0.012). Mechanical deformations were prevalent in 97.5% of needles, with TL showing greater deformations than STF after single and repeated uses. Barbs were more common in TL (90/100) than STF (84/100), with a higher relative risk for barbed-like deformation in TL (RR single use: 1.26; p < 0.001; multiple use: 7.87, p < 0.001). The short triple facet-designed bevel demonstrated significantly less mechanical deformation, suggesting potential advantages in maintaining needle lumen patency. The intraligamentary needle bevel design is linked to mechanical deformation and anesthetic success after repetitive use, but not to puncture pain.

Design of Z-fiber Guiding Needle for Composite Material Preform with Large-Thickness and High-Density

Design of Z-fiber Guiding Needle for Composite Material Preform with Large-Thickness and High-Density

Assessing Tissue Damage Around a Tape Spring Steerable Needle With Sharp Turn Radii.

Steerable needles are a novel technology that offers a wide range of uses in medical diagnostics and therapeutics. Currently, there exist several steerable needle designs in the literature, however, they are limited in their use by the number of possible turns, turn radius, and tissue damage. We introduce a novel design of a tape spring steerable needle, capable of multiple turns, that minimizes tissue damage. In this study, we measure the turning radius of our steerable needle in porcine liver tissue in vitro with ultrasound and estimate tissue damage in gel blocks using image analysis and 3D plaster casting. We were able to demonstrate our steerable needle's ability to steer through biological tissue, as well as introduce a novel method for estimating tissue damage. Our findings show that our needle design showed lower damage compared to similar designs in literature, as well as tissue stiffness being a protective factor against tissue damage.

Bursa International Silk Needle Lade Festival and Design Competition

Bursa International Silk Needle Lade Festival and Design Competition

Role of Endoscopic Ultrasound in Diagnosis of Pancreatic Ductal Adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is the most common (90%) type of solid pancreatic neoplasm. Due to its late presentation and poor survival rate, early diagnosis and timely treatment is of utmost importance for better clinical outcomes. Endoscopic ultrasound provides high-resolution images of the pancreas and has excellent sensitivity in the diagnosis of even small (<2 cm) pancreatic lesions. Apart from imaging, it also has an advantage of tissue acquisition (EUS fine-needle aspiration, FNA; or fine-needle biopsy, FNB) for definitive diagnoses. EUS-guided tissue acquisition plays a crucial role in genomic and molecular studies, which in today's era of personalized medicine, are likely to become important components of PDAC management. With the use of better needle designs and technical advancements, EUS has now become an indispensable tool in the management of PDAC. Lastly, artificial intelligence for the detection of pancreatic lesions and newer automated needles for tissue acquisition will obviate observer dependency in the near future, resulting in the wider dissemination and adoption of this technology for improved outcomes in patients with PDAC.

In-Silico Analysis of Optimal Configurations for Rotational Bioinspired Bone Marrow Biopsy Needle Designs: An ANN Approach.

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.

Positive Pressure and Negative Pressure Irrigation Dynamics with Different Needle Designs Using Computational Fluid Dynamics

This study aimed to investigate the irrigation dynamics of the positive pressure side-vented (SV) needle, EndoVac (micropores) needle and modified apical negative pressure (mANP) open-ended needle using computational fluid dynamics (CFD). A simulation of a prepared root canal (conical frustum) of 15 mm length with an apical diameter of 0.40 mm following Protaper F4 apical preparation was created using three-dimensional (3D) CAD software. The 3D simulated needle of SV 30G needle, EndoVac with micropores needle and mANP, 30G flat open-ended needle were also created. The irrigation dynamics were evaluated through transient CFD simulations. In addition, the irrigation dynamics of mANP at 0.2 mm, 0.5 mm, and 1.0 mm short from the working length were also assessed. The EndoVac and mANP showed negative apical static pressure and streamline patterns able to reach the apical region, thus indicating negligible extrusion. Meanwhile, SV showed positive apical static pressure and almost nonexistent streamlines beyond the needle tip. The SV showed the highest wall shear stress (WSS) magnitude of 1030Pa whereas Endovac (161 Pa) and mANP1 (258 Pa). However, SV revealed lower average WSS (10 Pa) compared to mANP1 (13 Pa) and mANP2 (11 Pa). This is due to SV developed a localised maximum WSS opposite the open vent area only therefore, uneven distribution of WSS. The EndoVac system developed a localised maximum WSS in the pair of micropores furthest away from the apical. CFD analysis of the EndoVac, mANP and SV showed different technique approach, needle design and needle depths insertion affect the irrigation dynamics pattern and magnitude.

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA): revolutionizing the landscape of lung disease diagnostics.

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has emerged as a revolutionary diagnostic tool for lung diseases, including lung cancer, sarcoidosis, and lymphoproliferative diseases. This minimally invasive procedure offers a superior diagnostic yield while ensuring maximum patient safety when compared to traditional invasive techniques such as mediastinoscopy and thoracoscopy. By enabling real-time imaging and sampling of mediastinal and hilar lymph nodes and masses directly from the bronchoscope, EBUS-TBNA has redefined the precision of diagnostic bronchoscopy. This comprehensive review explores the origins, development, and current status of EBUS-TBNA, highlighting its successes and identifying potential areas for improvement. Technological advancements have continuously enhanced the reliability and efficacy of EBUS-TBNA over time. The mechanisms underlying the superior diagnostic yield of EBUS-TBNA are thoroughly discussed, further solidifying its position as the gold standard for lung cancer staging and diagnosis. Furthermore, this review delves into the crucial role of EBUS-TBNA in lung cancer diagnosis, supported by studies comparing its accuracy, safety, and cost-effectiveness to other diagnostic tools. Looking ahead, ongoing research aims to expand the applications of EBUS-TBNA and improve its diagnostic performance. Notable advancements in needle design and sampling techniques hold promise for further enhancing its efficacy. Maximizing its potential through comprehensive training and continuous technological developments will enable broader clinical applications, ultimately leading to improved patient outcomes. As EBUS-TBNA continues to evolve, its diagnostic impact is expected to increase, solidifying its position as an indispensable tool in the diagnosis and management of lung diseases.

"Optimization of MRI Polymer-Based Biopsy Needle Design Using Finite Element Analysis"

"Optimization of MRI Polymer-Based Biopsy Needle Design Using Finite Element Analysis"