Depth Of Needle Penetration Research Articles

An Experimental Study of the Needled Nonwoven Process

This part of the series deals with the measurement of fiber damage caused by needle punching. A critical step in the experimental determination of fiber damage is to unravel fibers from needled nonwoven fabrics. This is achieved by using a feed web containing water-soluble fibers and a small percentage of wool. After needling, the fabric is put in hot water to dissolve the water-soluble fibers, leaving unconnected loose wool fibers. Damage due to needling may be in two forms, complete fiber breakage and fiber weakening. Fiber breakage is measured in terms of fiber length reduction, while fiber weakening is measured in terms of the reduction of fiber bundle strength. Needle-loom and feed web conditions, such as needling density, depth of needle penetration, needle design, web thickness, and methods of feeding the web to the needle loom, are investigated for their influence on fiber damage.

Evaluation of Apical Debris Removal Using Various Sizes and Tapers of ProFile GT Files

The purpose of this study was to evaluate the effect of preparation taper using size #20 or size #40 ProFile GT files on the ability to introduce irrigant and remove debris from root canals. Forty-eight bilaterally matched pairs of extracted teeth were instrumented using.04-,.06-,.08-, and.10-tapered files with one tooth of each pair enlarged to size #20 and the other to size #40. The teeth were sectioned at 1 mm and 3 mm from the apex, and the amount of remaining debris was calculated as a percentage of the total lumen area. The following variables were evaluated: apical preparation size, preparation taper, total volume of irrigation, depth of irrigation needle penetration, and number of instrument changes needed to reach working length. Compared with the size #40 preparations, a significantly greater percentage of remaining debris was observed in the size #20 preparations at the 1-mm level for all tapers except the.10 taper group in which there was no significant difference (p = 0.982). There were no significant differences between any groups at 3 mm. Results suggest that debris is more effectively removed using.04,.06, and.08 ProFile GT instruments when the apical preparation size is larger (size #40) compared with size #20 apical preparations. When a taper of.10 can be produced at the apical extent of the canal, there is no difference in debris removal between the two preparations sizes.

Use of biopsy sheath to improve standardization of renal mass biopsy in tissue-ablative procedures.

We used a biopsy sheath to standardize and improve biopsy specimens obtained during laparoscopic cryoablation. Tru-Cut biopsy was performed using a resized sheath in three patients undergoing laparoscopic cryoablation of renal masses. All three biopsy specimens were sufficient for pathologic evaluation and representative of the tissue mass. The application of a biopsy sheath to standardize the depth of needle penetration during Tru-Cut biopsy provides better results and minimizes false-negative studies.

Evaluating the Effectiveness of Bifid Medical Needles for Protection from Needle-Stick Injuries

Most blood-borne pathogen transmissions in the healthcare industry are caused by needle-stick injuries, and protection from sharp invasive instruments is of great concern. Recently, a modified design of medical needles (bifid needles) has been proposed to prevent needle-stick injuries. The bifid needle is designed to provide protection for users by entangling itself with an article of personal protective clothing. The purpose of this research is to study the effectiveness of bifid medical needles for protection against needle-stick injuries. A comparison of bifid and standard needles is conducted by evalu ating the forces experienced by the needle during penetration through Spectra 1000® woven fabric using a force measurement device. A predictive model is derived, expressing resistance to needle penetration in terms of needle and fabric parameters. Our study shows that bifid and standard needles behave differently when penetrating through a fabric. The predictive model indicates that the independent parameters of fabric orientation, needle penetration depth, and needle gap and their interactions significantly affect fabric resis tance to needle penetration.

Consumer‐specified Instrumental Quality of Short‐dough Cookie Texture Using Penetrometry and Break Force

ABSTRACT: Consumers' ratings of overall textural quality during the initial biting and crushing of the cookie were influenced by stimulation to the senses generated from the total number of cracks for a given depth of needle penetration and the proportions of cracks low (0.03 to 0.05 N) and high (> 1 N) in force, at least as strongly as by effects of 3‐point break force. Spontaneous descriptions of the sensed effects of denting, breaking, and crushing the cookie, were less often discriminatively sensitive to the fracture dynamics than was overall texture. Thus, penetrometry provides effective measures for consumer‐discriminated texture quality of cookies.

Evaluation of the percutaneous intramyocardial injection for local myocardial treatment

Therapeutic angiogenesis requires the induction of new blood vessel formation for the treatment of peripheral vascular and coronary artery disease. Efficacious application of this new therapy requires optimizing multiple factors, including the therapeutic agent, dosing, frequency of administration, and delivery modality. In this study, a helical needle drug infusion catheter was applied for optimal application of percutaneous intramyocardial delivery (PIMD). (125)Iodine-labeled albumin was injected by PIMD into the left ventricle myocardium in eight swine. After 1 hr, PIMD resulted in a high concentration of radiolabel at the treatment site; 16.4% +/- 2.1% of delivered and 81.4% +/- 2.6% of the total cardiac activity was concentrated at the site of delivery. The depth of needle penetration correlated with the myocardial retention of delivered protein. The myocardial retention of radiolabel in animals with shallow injections was 10.1% +/- 0.8%, compared to 18.9% +/- 3.3% retention after deep injections. The specific activity at the treatment site (radioactive counts per gram of tissue) was 115 +/- 36, 226 +/- 55, and 47 +/- 10 times higher compared to liver, lung, and kidney, respectively. Continuous coronary sinus and aortic blood sampling indicates that within 15 min following intramyocardial injection, a significant amount of nonretained protein is found within the coronary sinus. This study defines some of the parameters that can affect optimal application of PIMD and demonstrates that PIMD is a safe and efficient method for local drug delivery.

Laparoscopic implant instrument for the placement of intramuscular electrodes in the diaphragm.

We have developed an endoscopic instrument that will allow a surgeon to safely, dependably and accurately place intramuscular (IM) electrodes in the diaphragm. This instrument has been used to implant 28 IM electrodes in the diaphragms of eleven acute and four chronic dogs. All electrodes achieved full activation of the diaphragm muscle, producing tidal volumes up to 130% V(TCRIT), the critical volume necessary for basal ventilatory support, with unilateral stimulation. The surgeon is able to control the angle of the IM electrode insertion needle, which enables the needle to approach the diaphragm at an angle that is parallel to the surface of the muscle. This insures good control over the depth of needle penetration into the muscle, which greatly reduces the risk of accidentally passing the needle through the diaphragm and entering the thorax. Endoscopic placement of IM electrodes into the diaphragm opens opportunities to provide cost effective negative pressure ventilation to patients who are unable to effect sufficient ventilation by central nervous system (CNS) control of respiration.

Quantity of Blood Inoculated in a Needlestick Injury From Suture Needles

We wanted to quantify the amount of blood inoculum present on several commonly used surgical and phlebotomy needles and to determine the effect of single or double gloving, the depth of needle penetration and needle size on inoculum volume. Nineteen, 22 gauge and 25 gauge phlebotomy needles, as well as the tapered suture needles from zero, 3-0 and 5-0 sutures and a cutting needle from a 4-0 suture were assessed. The needles were dipped into blood labeled with 125I-epidermal growth factor and then embedded 2 or 5 millimeters into an agarose gel. The volume of blood inoculum ranged from 133 to 683 nanoliters for the phlebotomy needles and from 35 to 366 nanoliters for the suture needles. Needles were then passed through none, one or two layers of surgical glove material before embedding the needles 5 millimeters into agarose gel. The use of one layer of surgical glove resulted in a significant (p < 0.001) decrease in inoculum from tapered suture needles, but not from the cutting needles. Two gloves were even more efficient (p < 0.001) than one glove at removing blood from all suture needles, including the cutting needle. However, surgical glove material did not significantly reduce the volume of blood inoculum transferred by the phlebotomy needles. The size of the needle and depth of penetration were found to have a significant influence on inoculum.

Efficacy of Gloves in Reducing Blood Volumes Transferred during Simulated Needlestick Injury

This study was designed to evaluate factors that affect blood volumes transferred to skin during simulated needlestick injuries in an in vitro paper prefilter model and an ex vivo porcine tissue model. The effect of needle type and size, penetration depth, and glove use on the volume of radiolabeled blood transferred was determined in each model. Blood volumes ranged from 0.47 +/- 0.26 microL (30-gauge needle, 0.5-cm depth, in vitro model) to 5.88 +/- 1.45 microL (18-gauge needle, 2.0-cm depth, in vitro model). Needle size and penetration depth were significantly associated with transfer volume. Glove material reduced the transferred blood volume by 46%-86% in both models. Transfer volumes were within the same order of magnitude for all conditions. Hence, virus titer in the source blood may be a better predictor of needlestick infectivity than is exposure volume. Regardless, gloves may exert some protective effect and should be worn whenever needles are handled.

Further observations on mandibular anaesthesia

Recent studies have emphasized that none of the accepted intraoral landmarks used in the conventional mandibular block technique is completely reliable, nor can they presage those instances in which the lingula presents an obstruction to the needle pathway. An answer to this problem is suggested by the use of extraoral landmarks to assist in estimating the height and expected depth of needle penetration. The importance of palpating for the anterior border of the medial pterygoid muscle deep in the pterygotemporal depression is reaffirmed.