News Column

Patent Issued for Method of Providing Hemostasis Using Flexible Bioresorbable Foam

July 15, 2014



By a News Reporter-Staff News Editor at Life Science Weekly -- Medtronic, Inc. (Minneapolis, MN) has been issued patent number 8765715, according to news reporting originating out of Alexandria, Virginia, by NewsRx editors (see also Medtronic, Inc.).

The patent's inventors are Oliver, Dana A. (Jacksonville, FL); Halversen, Matthew J. (Hopkinton, NH); Hodge, Aimee (Candia, NH).

This patent was filed on November 20, 2012 and was published online on July 1, 2014.

From the background information supplied by the inventors, news correspondents obtained the following quote: "Various types of sterile packing and stents are used in the medical and surgical fields for keeping tissues apart or preventing adhesion. Such uses include, but are not limited to, nasal packing and sinus stents, packing for inner ear surgery, tympanoplasty, exostosis, orbital decompression, as well as various orifice restenosis prevention uses. Personal uses such as tampons, bandaging and the like also involved sterile packing materials.

"Such packing and stents have been made from gauzes, microfibers, nonfibrous expandable packing, such as tampons, and the like. Resorbable packing and stent devices have also been developed. Such packing materials have typically included hyaluronic acid (HA), or salts of hyaluronic acids, which are naturally occurring mucopolysaccharides found in various body fluids and connective tissues. Thus, HA is biocompatible. It has been adapted for use as a surgical aid to prevent tissue contact and adhesion formation.

"Crosslinking has created somewhat insoluble HA materials. Further, other biocompatible materials such as polysaccharides, especially methylcellulosic materials have been combined with the hyaluronic acid to produce packing materials which are resorbable but are also insoluble and have a longer in-vivo residence time before they dissolve into gels and are absorbed by the body tissues. These materials also have increased fluid absorption capabilities.

"Collagen is also known for use in the medical field; it is a major protein constituent of connective tissue and is widely used in medical and surgical applications such as sutures, grafts and surgical prostheses. Typical sources include calfskin, bovine Achilles tendons, cattle bones, porcine tissue, human cadaver tissue, and rat tails. Collagen, as an animal protein, is bioresorbable, even when crosslinked to reasonable levels. Collagen is available in a variety of forms including powders and fibrils, and in aqueous solution. Collagen may be provided in insoluble or soluble forms.

"It has now been discovered that a flexible bioresorbable foam for packing, post-operative use, and other medical uses may be created having both hemostatic properties and a resorption time of about 14 days (also known as an in-vivo residence time). The foam is formed from carboxymethylcellulose (CMC)."

Supplementing the background information on this patent, NewsRx reporters also obtained the inventors' summary information for this patent: "An embodiment of the invention is directed to a method of providing hemostasis of bleeding tissue. A flexible bioresorbable foam is formed that consists essentially of carboxymethylcellulose. The flexible bioresorbable foam is crosslinked.

"Chain scission is performed on the crosslinked flexible bioresorbable foam to provide the flexible bioresorbable foam with a selected in-vivo residence time of between about 3 days and about 14 days. Hemostasis is caused by applying the flexible bioresorbable foam to bleeding tissue.

"The flexible bioresorbable foam is resorbed in-vivo. The selected in-vivo residence time is a time between the flexible bioresorbable foam being applied to the tissue and the flexible bioresorbable foam having been substantially completely absorbed into the tissue.

"Another embodiment of the invention is directed to a method for preventing adhesion of bleeding tissue. A flexible bioresorbable foam is formed that consists essentially of carboxymethylcellulose. The flexible bioresorbable foam is crosslinked.

"Chain scission is performed on the crosslinked flexible bioresorbable foam to provide the flexible bioresorbable foam with a selected in-vivo residence time of between about 3 days and about 14 days. The bleeding tissue is hydrated and separated with the flexible bioresorbable foam to prevent adhesion.

"The flexible bioresorbable foam is resorbed in-vivo. The selected in-vivo residence time is a time between the flexible bioresorbable foam being applied to the tissue and the flexible bioresorbable foam having been substantially completely absorbed into the tissue.

"Another embodiment of the invention is directed to a method of providing hemostasis of bleeding tissue. A flexible bioresorbable foam is formed that consists essentially of carboxymethylcellulose and a drug. The flexible bioresorbable foam is crosslinked.

"Chain scission is performed on the crosslinked flexible bioresorbable foam to provide the flexible bioresorbable foam with a selected in-vivo residence time of between about 3 days and about 14 days. Hemostasis is caused by applying the flexible bioresorbable foam to bleeding tissue.

"The flexible bioresorbable foam is resorbed in-vivo. The selected in-vivo residence time is a time between the flexible bioresorbable foam being applied to the tissue and the flexible bioresorbable foam having been substantially completely absorbed into the tissue. The drug is released as the flexible bioresorbable foam is resorbed in-vivo.

"These terms when used herein have the following meanings.

"The term 'bioresorbable' as used herein, means capable of being absorbed by the body.

"The term 'hemostat' means a device or material which stops blood flow.

"The term 'stent' means a material or device used for separating tissue and holding it in such separated position.

"The term 'lyophilizing' means freeze-drying.

"The term 'resorption time' and 'in-vivo residence time' are used interchangeably, and refer to the time between insertion into the body and the time at which the material has been substantially completely absorbed into the tissues.

"The term 'adhesion' as used herein, refers to the sticking together of tissues which are in intimate contact for extended periods.

"The term 'dehydrothermal crosslinking' means crosslinking accomplished by application of high temperatures and/or low pressures to a material."

For the URL and additional information on this patent, see: Oliver, Dana A.; Halversen, Matthew J.; Hodge, Aimee. Method of Providing Hemostasis Using Flexible Bioresorbable Foam. U.S. Patent Number 8765715, filed November 20, 2012, and published online on July 1, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8765715.PN.&OS=PN/8765715RS=PN/8765715

Keywords for this news article include: Medtronic Inc, Extracellular Matrix Proteins.

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC


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Source: Life Science Weekly


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