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Magnified schematical drawing of the front half of four examined trocar needle designs: back bevel (A), spear bevel (B), lancet bevel (C), and spatula bevel (D). An inner stiletto of trocar cannula systems was composed of a sharp tip with a beveled face on the main needle shaft. The left needle showed a bevel-faced needle. The next tip of the spear bevel was sharply angled in a triangular shape. The lancet bevel had the biggest diameter and an edge behind the primary bevel. The right tip of a spatula bevel had a round frontier by a backcut method.
Source publication
Background:
To investigate the geometry, penetration force, and cutting profile of 23-gauge trocar systems for pars plana vitrectomy based on their grinding methods in a standardized laboratory setting.
Methods:
In this experimental study, Eleven different commercially available 23-gauge sclerotomy trocar systems were divided into 4 groups accor...
Context in source publication
Citations
... Further, it is observed that the qualitative trend of VMS along the needle penetration length (for no rotation case) matches well with the experimental studies reported in Refs. (Meyer et al. 2014;Matthews et al. 2014;Ramezanpour et al. 2015;Okamura et al. 2004;Kataoka et al. 2002;Kobayashi et al. 2009) for a mesh size of 0.92 mm . Therefore, a mesh element size of 0.92 mm corresponding to 8431 global mesh elements is considered optimum and is finalized. ...
... However, since manual insertion is reported in the experimental study, the data extracted from the region of interest in the figure underwent x-axis scaling using MAT-LAB. A similar qualitative pattern of the reaction force along the needle penetration length for a 23 − G bevel (Fig. 4) is also validated with the one reported for polyurethane foil (Fig. 3 in Ref. (Meyer et al. 2014)). Further, alike related patterns on needle insertion has also been observed in several experimental studies performed on artificial and biological tissues (Ramezanpour et al. 2015;Okamura et al. 2004;Bao et al. 2016;Abolhassani et al. 2004Abolhassani et al. , 2007aKobayashi et al. 2009;Wang et al. 2013), bovine livers (Gokgol et al. 2012), and canine prostate (Kataoka et al. 2002). ...
... A baseline study is carried out subject to the baseline parameters mentioned in Table 3 to investigate the effect of needle interaction with the ocular tissue when the needle is not rotating. The baseline parameters have been taken from several literature studies (Gokgol et al. 2012;Matthews et al. 2014;Meyer et al. 2014;Okamura et al. 2004;van Gerwen et al. 2012) that have experimentally investigated the needle interaction with the ocular tissue without rotating the needle. Figure 4 shows the variation of reaction forces on sclera concerning needle penetration length. ...
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.
... Özetle SPEEP modu venturi pompasının etkinliğini peristaltik pompanın güvenliğiyle birleştiriyor. [1][2][3][4] İnfüzyon, yerçekimiyle veya aktif (BSS içine basınçlı hava verilerek) olabilir ve aspirasyon, 60 mL/dak'ya kadar akışa ve 650 mmHg vakuma izin verir. İnfüzyon ayak pedalından manuel olarak da vaka esnasında ayarlanabilir. ...
Vitrectomy operations, which started with the construction of the first prototypes of vitrectomy devices in the early 1970s, have become increasingly widespread in parallel with technological developments until today. With the developments in pump systems, lighting systems and laser systems, patient safety and surgeon comfort are increasing. There are many companies producing vitrectomy devices in the market. Each device has some features that are superior to the other. The current vitrectomy device of Oertli, which has been working in this field since the prototype of the first vitrectomy device, is OS4. In this review, we will give information about the OS4 vitrectomy device of Oertli.
... Kanülün distal ucu, skleradan düzgün penetrasyonu kolaylaştırmak ve doku travmasını azaltmak için eğimli veya koniktir. 8, 9 Obturatör, skleranın ilk penetrasyonuna yardımcı olan trokarın çıkarılabilir bir bileşenidir. Yerleştirme sırasında kanülün içine yerleştirilen katı, sivri bir çubuktur. ...
... İstenen derinliğe ulaşıldığında, obturatör geri çekilir ve kanül yerinde bırakılır. 9 Göz içi basıncını korumak ve ameliyat sırasında sıvı sızıntısını önlemek için trokarlar sızdırmazlık mekanizmaları kullanır. [9][10][11] Valf contaları veya yaylı contalar, kanül içinde aletlerin geçmesine izin verir ancak aletler geri çekildiğinde kendiliğinden sızdırmazlık etkisi yaratır. ...
... 9 Göz içi basıncını korumak ve ameliyat sırasında sıvı sızıntısını önlemek için trokarlar sızdırmazlık mekanizmaları kullanır. [9][10][11] Valf contaları veya yaylı contalar, kanül içinde aletlerin geçmesine izin verir ancak aletler geri çekildiğinde kendiliğinden sızdırmazlık etkisi yaratır. Bu mekanizma minimum sıvı çıkışını sağlayarak stabil bir göz içi ortamı sağlar. ...
Vitrectomy, a surgical procedure for treating various retinal disorders, has evolved significantly with advancements in instrumentation and techniques. Trocars, probes, and duty cycles are integral components of vitrectomy devices, playing crucial roles in ensuring optimal surgical outcomes. This review aims to provide a comprehensive analysis of trocars, probes, and duty cycles, exploring their functionality, advancements, and their impact on vitrectomy surgery. By understanding the intricate details of these components, ophthalmic surgeons can enhance their surgical precision, efficiency, and patient outcomes.
... Five phases were identified in the insertion test diagram. [19,29,30] Phase I: The needle comes into contact with the pork loin sample, which results in In Figure 3, one can observe that regardless of the liquid precursor employed, all of the coatings reduced insertion and extraction forces compared to spinal needles (noncoated). Significant statistical differences (p < 0.001) were found in friction, insertion, and extraction forces obtained by the three liquid precursors and the four configurations analyzed (Supporting Information: Tables S2-S4). ...
The global needle market is growing due to an increase in the geriatric population, chronic diseases, and the high demand for vaccines. High insertion forces cause unpleasant effects on patients, needle deformation, and tissue displacement, affecting the accuracy of the methods. To reduce insertion forces, atmospheric‐pressure plasma‐polymerized coatings were deposited on spinal needles. The influence of liquid precursor, plasma power, precursor gas flow, and treatment time has been analyzed. To avoid plasma‐polymerized coatings detached after the injection test, it is necessary to apply a precursor that not only has antifriction molecules (siloxane) but also has particles that promote the durability of the coatings (amines). N1‐(3‐trimethoxysilylpropyl)diethylenetriamine (TRIAP) was the most effective, reducing insertion–extraction forces regarding noncoated spinal needles, by 75% and 50%, respectively. The global needle market is growing due to an increase in the geriatric population, chronic diseases, and the high demand for vaccines. High insertion forces cause unpleasant effects on patients, needle deformation, and tissue displacement, affecting the accuracy of the methods. To reduce insertion forces, atmospheric‐pressure plasma‐polymerized coatings were deposited on spinal needles. The influence of liquid precursor, plasma power, precursor gas flow, and treatment time has been analyzed.
... The authors, therefore, chose 0.1 mm thickness vinyl membrane to form the aneurysm. A trocar-tipped needle was used to penetrate the aneurysm because it needs the least force for penetration [9]. The needle was 21 G because the available coils can easily pass through it Nester push-able coils were used because they were MRI compatible. ...
Aim of the study
Endovascular coiling has gained worldwide acceptance in the management of intracranial aneurysms. However, not all aneurysms can be coiled. Direct aneurysm puncture with aneurysm thrombosis has been performed, using coils for extracranial aneurysms and iron filings for intracranial aneurysms. Therefore, the feasibility of stereotactic aneurysm coiling with direct aneurysm puncture using Nester-coils was studied in an in vitro model.
Methods and findings
Twenty-eight aneurysms measuring 9–21 mm in diameters (median 14 mm) were made using 0.1 mm vinyl film that was connected to a monometer with 73 cm of water column. Twenty-three aneurysms were coiled through direct puncture of the aneurysms using a stereotactic frame. Five were coiled using a hand-held probe carrier.
Statistical analysis of the data was conducted by data analysis feature of Microsoft Excel.
Findings
The study showed that needle puncture of the aneurysm and coiling of the aneurysm through the needle can be done with ease and without any significant fluid leak from the puncture site. It also shows that the coil will stay within the aneurysm without entering the neck. The study also shows that this method can be done using free-hand technique. Furthermore, it shows that the probe holder for the needle can also be used as an aneurysm stabilizer and as a tamponade.
... The lancet used in this study (Accu-Check, Safe-T-Pro-Plus, Roche Diagnostics, USA) had an outer diameter of 0.64 mm, and three bevelled faces: a primary bevel and two bevels on each side of the primary bevel (Fig. 1). The three bevelled faces form a sharp point that facilitates cleaving the tissue [20]. A high-speed video of the lancet being propelled by its spring into air, showed that at a depth setting of 2.3 mm, the lancet travelled forward by 1.92 mm at a maximum speed of 4.8 m/s, before retracting with a maximum speed of 2.4 m/s. ...
Objective:
Needle free jet injection is a drug delivery technique that uses the momentum of the fluid drug to break through the skin. This technique has recently also been applied to blood release, aiming to collect samples from capillaries in the skin without needing a lancet prick. This work provides new information about the wound geometry and tissue disruption caused by shallow jet injection with circular shaped and slot shaped jets.
Methods:
We use histological analysis to compare the disruption of tissue, including blood vessels, caused by lancet-pricking and jet injection with a circular shaped jet and a lancet-inspired slot shaped jet.
Results:
Intradermal injection into porcine skin using a slot shaped jet disrupted more vascular endothelium in the tissue than a circular shaped jet and did so at a smaller penetration depth with smaller wound volume. Our results suggest that shallow jet injections may have the potential to release more capillary blood than a lancet prick.
Conclusion:
These findings demonstrate that a reversible jet injector might be used in diabetes management as a device to release and collect blood samples, in addition to being used to deliver insulin.
Significance:
Tissue disruption is crucial to consider when using jet injection to deliver drug and release capillary blood.
... Therefore, it is important to minimize the needle insertion force of the hair implant needle. Several studies on the relationship between hair implant needle design and insertion force used simulation to improve procedure accuracy by evaluating the insertion force of the biopsy needle or trocar system [10][11][12]. Okamura et al. [10] analyzed the needle insertion process using computerized tomography data and investigated the needle insertion force based on differences in needle diameter and tip geometry. ...
... The blade and conical trocars showed a large insertion force [11]. Meyer et al. [12] compared the insertion force of commercial trocar systems for pars plana vitrectomy. They established a standardized experiment in compliance with the International Organization for Standardization (ISO) standards and compared the needle insertion force based on needle geometry under the same experimental conditions. ...
... They established a standardized experiment in compliance with the International Organization for Standardization (ISO) standards and compared the needle insertion force based on needle geometry under the same experimental conditions. The lancet and back bevel-type needles showed a low insertion force [12]. Results showed that the sharper the needle tip, the lower was the insertion force. ...
Surgeons insert approximately 3000 hair implants in a single hair restoration surgery, and the needle shape critically affects surgical performance including surgical time, survival rate, and the surgeon's fatigue. There are several experimental studies on the relationship between needle shape and performance; however, there are no studies on hair implant needles, which are different from other medical needles as they have a comparatively short bevel. This study compared several hair implant needles to determine the relationship between needle shape and insertion force. Eight hair implant needles with the same diameter were collected, and their geometrical data were visually measured. The insertion force and total work of each needle were measured using custom-made force measurement equipment; the results were statistically compared, and their correlation was analyzed. Moreover, a qualitative comparison was made. The needle insertion force ranged from 1.30 to 2.97 N, and the total work ranged from 8.15 to 10.97 mJ. The primary bevel and acute angles showed a moderate positive correlation with the total work. A longer point length, smaller primary bevel, and acute angle decrease the total work of hair implant needles. As per the results of the qualitative comparison, we found that the surgeons can identify the differences in needle insertion force among various hair implant needles, and their grading was consistent with the grading according to the total work of needle insertion.
... The needlepoint, also known as "lancet point," is the sharpest point of any medical needle. 10 The typical design of a needlepoint frequently presents three-bevel cuts: the primary bevel, which is the surfaced as a result of grinding the tube at a specific angle α, and the two-side bevels, which are secondary grind angle β on each side of the primary bevel to form the cutting edge and a sharp needlepoint. The bevel length is by definition the longest distance of a bevel, measured from the tip of the needle to the most proximate area of grinding behind the heel. ...
Purpose:
Pen needles used for insulin injections can have different characteristics that affect a patient's injection experience. The aim of the study was to investigate in a standardized laboratory setting the penetration force and sliding force of different 31/32/33/34 gauge pen needles available in 3.5/4/5/8 mm length and 3/5 bevel tips for subcutaneous injection through pen needles and injection pens.
Methods:
Eight different commercially available pen needles were tested in this experimental study. The needle was inserted into a polyurethane substrate at a specific constant speed and the force for insertion was recorded as a function of penetration depth. A load cell was utilized to measure force during the different stages of insertion.
Results:
Maximum load was lower with the PiC G32×4 when compared with the G32×4 5-bevel needle (p<0.0001), while it was not significantly lower with the PiC G32×4 when compared to the G32×4 3-bevel needle (p=0.064). The comparison of G33×4 PiC and G34×3.5 PiC needles with G32 needles demonstrated significantly lower maximum loads with G33 and G34 (p<0.0001). No difference between needles emerged for sliding results.
Conclusion:
Newer pen needles represent a significant improvement in insulin delivery, reducing the amount of force required to penetrate tissues. Needle tip sharpness and other factors that can reduce the force of insertion such as lubrication are important parameters that can be optimized to increase patient acceptance.
... The ease of penetration and the pressure exerted on the abdomen depend on the spring rate, the forces required to retract the stylet, the bevel design, and the sharpness of the VN used. Although cannulas with lancet bevel designs required less penetration force than back-bevel design cannulas in a previous study, 43 the opposite trend was found in our evaluation. In addition, the 2 VN selected for this study differed in spring rates and forces. ...
Objective
To evaluate the penetration depth (VNPD) of 2 disposable Veress needles (VN) at 4 insertion sites in the abdomen.
Study design
Descriptive study.
Sample population
Canine cadavers (n = 22, 6 for confirmation of the test methods and 16 for the comparative study).
Methods
Two disposable VN (VN A and VN B) were inserted at 4 sites (9th intercostal space [ICS] and preumbilical, paraumbilical, and subumbilical sites) in dorsally recumbent dogs by using a hand‐cranked jig. The VNPD was measured as the distance traveled by the VN between the subcutaneous tissue and the perforation of the peritoneum on the basis of audible clicks and visible feedback from the VN. The effects of the VN type and insertion site on the VNPD were analyzed by using a linear mixed‐effects model.
Results
VNPD varied between insertion sites (P = .01) and VN (P < .01). The VNPD was less at the 9th ICS than at the preumbilical, paraumbilical, and subumbilical sites. The maximal magnitude of change was 7.4 mm. Veress needle B (with a low spring rate, lower forces, and a back‐cut bevel design) penetrated farther than VN A (with a high spring rate, high forces, and a lancet‐type bevel) at 3 of 4 insertion sites. The maximal magnitude of change was 6.8 mm.
Conclusion
Veress needle penetration depth varied between VN designs but was the least at the 9th ICS in canine cadavers.
Clinical significance
Insertion of a VN at the 9th ICS is recommended to minimize its penetration into the abdomen. Associations between VNPD and mechanical factors, such as the sharpness and spring rate of VN, warrant additional research.
... Also, some of the one-step systems include lancet-pointed needle that would have remarkable low piercing and cutting forces. These devlopments may lead to smooth trocar insertion and more efficient wound closure [16]. We see that most of these innovations try to improve wound architecture by changing the blade structures and shapes and achieve a shape similar to MVR blades used in twostep sclerotomy technique. ...
PurposeTo find out the rate of suture requirement and post-operative hypotony in a series of 23-gauge pars plana vitrectomy cases and analyze the factors affecting post-operative hypotony and leakage of sclerotomy leading to suture placement. Methods
This is a single-center retrospective interventional case series. Eighty-four eyes underwent 23-gauge vitrectomy. Primary endpoint measures were rate of leakage of 23-gauge sclerotomies requiring suture placement at the end of surgery and rate of early post-operative hypotony. Secondary endpoint measures were risk factors for early hypotony and leakage requiring suture placement at the end of surgery. ResultsSuture placement in at least one sclerotomy because of sclerotomy leakage was required in 28.6 % (24 of 84) of eyes at the end of surgery. Early post-operative hypotony was seen in 14.3 % (12 of 84). Silicone oil endotamponade and single-step surgery were found as factors increasing the risk of sclerotomy leakage leading to suture placement. Suture placement was the only significant factor increasing the risk of early post-operative hypotony. Conclusion
Sclerotomy sutures may be required in 23-gauge surgery, more frequently in cases of single-step sclerotomy and/or silicone oil endotamponade. Meticulous suturation of leaking sclerotomies may decrease the rate of post-operative hypotony.
