Anesthesiology
Department of Biomedical Engineering and Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA.
Published: June 2009
Background: Differences in needle design may impact nerve localization. This study evaluates the electrical properties of two insulated Tuohy needles using computational finite element modeling.
Methods: Three-dimensional geometric computer-based models were created representing two 18-gauge, insulated Tuohy needles: (1) with an exposed metal tip and (2) with an insulated tip. The models were projected in simulated human tissue. Using finite element methodology, distributions of current-density were calculated. Voltages in the modeled medium were calculated, and activation patterns of a model nerve fiber around the tip of each needle were estimated using the activating function.
Results: Maximum current density on the exposed-tip needle occurred along the edge of the distal tip; the distal edge was 1.7 times larger than the side edges and 3.5 times larger than the proximal edge. Conversely, maximum current density occurred along the proximal edge of the insulated-tip Tuohy opening; the proximal edge was 1.9 times larger than the side edges of the opening and 3.5 times larger than the distal edge of the opening. Voltages generated by the exposed-tip needle were larger and had a wider spatial distribution than that of the insulated-tip needle, which restricted to the area immediately adjacent to the opening. Different changes in threshold were predicted to excite a nerve fiber as the needles were rotated or advanced toward the modeled nerve.
Conclusions: The needles displayed different asymmetric distributions of current density and positional effects on threshold. If this analysis is validated clinically, it may prove useful in testing stimulating needles before clinical application.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1097/ALN.0b013e3181a16275 | DOI Listing |
Curr Oncol Rep
January 2025
Radiation Oncology Department, General Regional Hospital "F.Miulli", Acquaviva Delle Fonti, Bari, Italy.
Purpose Of Review: Male breast cancer (MBC) is a rare entity which often arises in elderly people. Aim of this review is to evaluate the principal issues related to MBC in elderly, because the therapeutic management of disease is not only related to the biological behavior of the tumor, but also to the comorbidities and frailty of older population. A scoping literature review was performed on Pubmed and Cochrane Database using the following keywords: therapeutic management/ male/ breast cancer/ elderly patients.
View Article and Find Full Text PDFEcotoxicology
January 2025
Department of Biological Sciences, California State University, Sacramento, CA, 95819, USA.
Wildfires have become larger and more severe in recent decades. Fire retardant is one of the most common wildfire response tools to protect against loss of life and property. Previous studies have documented various effects of fire retardant, which commonly contains chemicals used in fertilizers, on plant and invertebrate community composition.
View Article and Find Full Text PDFPsychol Res
January 2025
Department of Psychology, Izmir University of Economics, Izmir, Turkey.
The Spatial-Numerical Association of Response Codes (SNARC) effect refers to the phenomenon of faster left-hand responses to smaller numbers and faster right-hand responses to larger ones. The current study examined the possible long-lasting effects of magnitude-relevant stimulus-response compatibility (SRC) practices on the SNARC effect in a transfer paradigm. Participants performed a magnitude classification task including either SNARC-compatible or SNARC-incompatible trials as practice.
View Article and Find Full Text PDFIntroduction: Health Professions Scholarship Program (HPSP) medical students typically enter the military with minimal military experience, commissioning specifically for the scholarship. During medical school, the only required training is a 5- to 6-week officer training course, which is neither specific to medicine nor guaranteed to be at the beginning of school, since it can be taken at any time. This lack of prior experience can lead to decreased confidence and understanding of the HPSP, specifically the medical school timeline leading up to the military match process and overall military.
View Article and Find Full Text PDFHeadache
January 2025
Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
Objective: Our primary objective was to evaluate the safety and feasibility of transcranial direct current stimulation combined with exercise therapy for the treatment of cervicogenic headache. Our exploratory objectives compared symptoms of headache, mood, pain, and quality of life between active and sham transcranial direct stimulation combined with exercise therapy.
Background: Cervicogenic headache arises from injury to the cervical spine or degenerative diseases impacting cervical spine structure resulting in pain, reduced quality of life, and impaired function.
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!
© LitMetric 2025. All rights reserved.