Soft tip cannula

Abstract

The present disclosure describes numerous example medical instruments that include an elongated portion having a proximal end and a distal end, and a passage defined therethrough and a soft tip coupled to the distal end of the elongated portion. The tip may be formed from a soft material. In some instances, the soft material may have a hardness less than the material forming the elongated portion. The tip may also include a passage that may be of a substantially equivalent size as the passage of the elongated portion. The tip may be coupled to the distal end of the elongated portion at an engagement site having a surface area greater than a cross-sectional area of the elongated portion.

What is claimed is: 
     
         1 . A method of forming a medical instrument comprising:
 preparing a distal end of an elongated portion for attachment of a soft tip comprising laser cutting, water jet cutting, milling, drilling, chemical etching, electrolytic etching, electron discharge machining, or a combination thereof;   attaching a tip to the distal end of the elongated portion comprising molding;   injection molding, insert molding, extrusion, adhering, or a combination thereof   
     
     
         2 . The method of  claim 1 , wherein the elongated portion comprises:
 a distal end; and   a first passage extending through the elongated portion,   wherein the tip comprises a second passage substantially equivalent in size to the first passage,   wherein the tip is coupled to the distal end of the elongated portion at an engagement site, and   wherein the engagement site has a surface area greater than a cross-sectional area of the instrument body.   
     
     
         3 . The method of  claim 2 , wherein the engagement site comprises a tongue and groove connection. 
     
     
         4 . The method of  claim 3 , wherein the tongue and groove connection comprises:
 at least one tongue formed on one of the elongated portion or the tip;   at least one groove formed on the other of the elongated portion or the tip,   wherein the at least one tongue and the at least one groove are interlocked with each other.   
     
     
         5 . The method of  claim 2 , wherein the engagement site comprises an enhanced surface to which the tip is molded. 
     
     
         6 . The method of  claim 2 , wherein the second passage is tapered. 
     
     
         7 . The method of  claim 1 , wherein the elongated portion comprises a needle or cannula. 
     
     
         8 . The method of  claim 7 , wherein the elongated portion has a gauge size of 25 or less. 
     
     
         9 . The method of  claim 1 , wherein at least a portion of the tip comprises silicone, polyurethane, polyethylene, polypropylene, polystyrene, polytetrafluoroethylene, fluorinated ethylene propylene (FEP), perfluoroalkoxy (PFA), polyether ether ketone (PEEK), polyetherimide (PEI), polyamide imide (PAI), thermoplastic polyimides (TPI), polybenzimidazol (PBI), rubber, latex, combinations thereof, or other polymer or plastic compounds.