Inductive Sensing to Detect Tissue Thickness Between Magnets for Potential Application in Magnetic Compression Based Anastomosis

2016 ◽  
Vol 10 (1) ◽  
Author(s):  
Anupama Arun ◽  
Brandon Gaston ◽  
Dillon Kwiat ◽  
Jill Imamura-Ching ◽  
Richard Fechter ◽  
...  
Keyword(s):  
Magnetic Force ◽  
Compressive Force ◽  
Critical Distance ◽  
Tissue Thickness ◽  
Compression Pressure ◽  
Magnetic Compression ◽  
Inductor Coil ◽  
Yorkshire Pigs ◽  
Inductance Sensor ◽  
Operating Surgeon

Magnetic compression based anastomoses use magnetic force to necrose tissue between two magnets to create an anastomosis. Nickel-plated neodymium–iron–boron magnets are used in our study. The compression pressure between the magnets depends on the distance between the magnets, which is determined by the thickness of the compressed tissue and depends on bowel wall thickness and elasticity. It is critical to know the distance between the magnets once the tissue is compressed because the magnets must be within a critical distance of each other in order to create enough compressive force to necrose the tissue. We have developed an inductance sensor to detect the distance (tissue thickness) between the two magnets after the surgeon has deployed them. Inductance sensing is a contact-less sensing method that enables precise short-range detection of conducting surfaces. The inductor coil mounted on one magnet detects the second magnet by measuring the change in inductance due to eddy current induced on the nickel-plated surface of the second magnet. The change in the inductance is proportional to the change in distance between the magnets. The sensor was first calibrated by using polycarbonate sheets to simulate the intestine tissue. We are able to detect up to 6 mm of spacing between the magnets. Pig intestine from Yorkshire pigs was used to characterize the sensor. We are able to distinguish up to five distinct layers of the intestine from the large intestine. This sensing mechanism can indicate the operating surgeon the exact thickness of the tissue compressed between the two magnets. The surgeon can thus be sure of formation of a clean anastomosis and avoid the likelihood of the magnets sliding away or uncoupling.

scholarly journals Finite Element Analysis and Experiment on Large Intestine End-to-End Anastomosis

2018 ◽  
Author(s):  
Ai Liao-yuan ◽  
Ge Shu-chen ◽  
Xu Jing-jing ◽  
Li Ming-yang ◽  
Mao Lin ◽  
...  
Keyword(s):  
Patient Outcomes ◽  
Postoperative Bleeding ◽  
Standard Of Care ◽  
Tissue Type ◽  
Tissue Thickness ◽  
Compression Pressure ◽  
Element Analysis ◽  
Inflammatory Bowel ◽  
The Impact ◽  
The Relationship

Colorectal surgery is widely performed to re-establish the bowel, the part of which is removed because of diverticulitis, intestinal polyps, inflammatory bowel and cancer. Stapled anastomosis is a highly standardized technique and considered the standard of care. However, complications like leakage, stenosis and postoperative bleeding cannot be completely avoided [1,2]. There is limited understanding of the impact of staplers on tissue and basic mechanics of tissue stapling. According to the previous research, compression, staple height, tissue thickness, tissue compressibility, and tissue type have an effect on the patient outcomes [3]. Hence, we conducted this prospective study to analyze the effect of staple height on tissue damage and compression pressure. An attempt was made to determine the relationship between the tissue height and the optimal closed staple height.

Portfindr: A Novel, More Accurate, and Precise Device for Locating Tissue Expander Ports

2020 ◽  
pp. 229255032096311
Author(s):  
Ian L. McCulloch ◽  
Jennifer Rokosz ◽  
Justin Chambers ◽  
W. Thomas McClellan
Keyword(s):  
Breast Reconstruction ◽  
Magnetic Force ◽  
Electronic Device ◽  
Tissue Expander ◽  
Common Method ◽  
Fluid Accumulation ◽  
Tissue Thickness ◽  
Two Stage ◽  
Support Structure ◽  
Tissue Expanders

Two-stage breast reconstruction is the most common method of reconstructive modality following mastectomy and requires serial saline infusions into temporary tissue expanders through subcutaneous ports. Historically, these ports were located using a small magnet attached to a string or support structure. Magnetic force decreases exponentially as tissue thickness or fluid accumulation creates more distance between the TE port and skin. We developed a prototype handheld electronic device, the PortFindr, which more accurately and precisely locates the centre of subcutaneous ports. This device may lead to more confident localization of ports, less inadvertent puncture of tissue expanders, and thus less complications during infusions.

Field-assisted ionization theory for microscopists

1994 ◽  
Vol 52 ◽  
pp. 820-821
Author(s):  
Patrick P. Camus
Keyword(s):  
Electric Field ◽  
Electron Tunneling ◽  
Ionization Probability ◽  
Critical Distance ◽  
Tunneling Probability ◽  
Field Ionization ◽  
Radius Of Curvature ◽  
Field Evaporation ◽  
A Value ◽  
Ion Emission

The theory of field ion emission is the study of electron tunneling probability enhanced by the application of a high electric field. At subnanometer distances and kilovolt potentials, the probability of tunneling of electrons increases markedly. Field ionization of gas atoms produce atomic resolution images of the surface of the specimen, while field evaporation of surface atoms sections the specimen. Details of emission theory may be found in monographs.Field ionization (FI) is the phenomena whereby an electric field assists in the ionization of gas atoms via tunneling. The tunneling probability is a maximum at a critical distance above the surface,xc, Fig. 1. Energy is required to ionize the gas atom at xc, I, but at a value reduced by the appliedelectric field, xcFe, while energy is recovered by placing the electron in the specimen, φ. The highest ionization probability occurs for those regions on the specimen that have the highest local electric field. Those atoms which protrude from the average surfacehave the smallest radius of curvature, the highest field and therefore produce the highest ionizationprobability and brightest spots on the imaging screen, Fig. 2. This technique is called field ion microscopy (FIM).

Influence of unbalanced magnetic force on shaft deflection in permanent magnet synchronous motor with fractional slot concentrated windings

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1461-1468
Author(s):  
Ting Dong ◽  
Juyan Huang ◽  
Bing Peng ◽  
Ling Jian
Keyword(s):  
Permanent Magnet ◽  
Magnetic Force ◽  
Permanent Magnet Synchronous Motor ◽  
Operational Reliability ◽  
Topology Structure ◽  
Permanent Magnet Synchronous Motors ◽  
Synchronous Motors ◽  
Shaft Deflection ◽  
Large Length ◽  
Fractional Slot

The calculation accuracy of unbalanced magnetic forces (UMF) is very important to the design of rotor length, because it will effect the shaft deflection. But in some permanent magnet synchronous motors (PMSMs) with fractional slot concentrated windings (FSCW), the UMF caused by asymmetrical stator topology structure is not considered in the existing deflection calculation, which is very fatal for the operational reliability, especially for the PMSMs with the large length-diameter ratio, such as submersible PMSMs. Therefore, the part of UMF in the asymmetrical stator topology structure PMSMs caused by the choice of pole-slot combinations is analysized in this paper, and a more accurate rotor deflection calculation method is also proposed.

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