Abstract A self-retaining surgical cannula comprises a catheter formed as a tube of elastic material, semirigid in character, such as polyethylene, polyvinyl chloride or silicone rubber, etc., with a perforate membranous front end tough, firm and sharp enough to be inserted into body tissue without being itself cut or torn by an internal rigid injection stylet or needle. A thin membranous ballooning portion of the tube contracts or deflates on insertion into the tissue and expands on application of fluid pressure within the catheter tube to lock the cannula in place. A rigid stylet or hollow needle, somewhat dull at its front end, is provided over which the catheter is placed for insertion into the tissue. A limit stop fixed on the catheter prevents overinsertion. The application stylet, which is formed to allow fluid to flow along it into the catheter front end, is withdrawn after the catheter tube is in place, leaving the latter flexible enough to permit movement of the patient and allowing needed surgical procedure while it remains in place in the tissue.
A cannula for penetration into and retention within soft body tissue, for injecting treating fluid into said tissue, comprising: a. A flexible catheter tube of resilient plastic material having adjacent its forward end a thin membranous part expandable into a balloon structure and having a front end closed and formed in a point to fit over and be inserted into said tissue by a stylet, said catheter including openings therein positioned adjacent said closed end to permit transmission of treating fluids from said catheter to surrounding tissue; b. A rigid stylet slideably mounted within said catheter and having its forward end formed into a point for supporting the pointed closed end of said flexible catheter during insertion in said tissue; c. And means connected to said catheter for supplying treating fluid therethrough to said body tissue.
Claim 2
Dependent Claim
136 words
A cannula for penetration into and retention within soft body tissue, for injecting treating fluid into said tissue, comprising: a. A flexible catheter tube of resilient plastic material having adjacent its forward end a thin membranous part expandable into a balloon structure and having a front end closed and formed in a point to fit over and be inserted into said tissue by a stylet, said catheter including openings therein positioned adjacent said closed end to permit transmission of treating fluids from said catheter to surrounding tissue; b. A rigid stylet slideably mounted within said catheter and having its forward end formed into a point for supporting the pointed closed end of said flexible catheter during insertion in said tissue; c. And means connected to said catheter for supplying treating fluid therethrough to said body tissue.
Claim 3
Dependent Claim
32 words
The combination set forth in claim 1 wherein said catheter includes a stop member formed integrally therewith and comprises an annular ring positioned to limit the depth of penetration of said catheter.