Abstract:
An apparatus for delivering aerosolized fibrin endoscopically to a wound is disclosed. The apparatus has a pair of syringes for holding fibrin precursors, a mixing chamber for mixing the fibrin precursors separately with pressurized gas to form individual aerosol solutions, and a delivery tube for delivery of the aerosol solutions to a remote surgical site for formation of an aerosolized fibrin seal.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Applicant&#39;s invention relates to an apparatus for delivering a biocompatible adhesive, more particularly aerosolized fibrin, endoscopically to a wound. 
     2. Background Information 
     Endoscopy is a surgical technique that involves the use of an endoscope, a special viewing instrument that allows a surgeon to see images of the body&#39;s internal structure through very small incisions. The endoscope itself consists of two basic parts. The first is a tubular probe fitted with a tiny camera and a bright light which is inserted through the small incision and the second is a viewing screen which magnifies the transmitted images of the body&#39;s internal structures from the camera. During surgery, the surgeon watches the screen while moving the tube of the endoscope through the surgical area. The endoscope functions as a viewing device only. To perform the surgery, a separate surgical instrument, such as a scalpel, scissors, or forceps, must be inserted through a different point of entry and manipulated within the tissue. 
     In a typical endoscopic procedure only a few small incisions, each preferably less than one inch long, are needed to insert the endoscope tube and other instruments. Since the incisions are shorter with endoscopy, the risk of sensory loss from nerve damage is decreased. Also, bleeding, bruising and swelling may be significantly reduced. 
     However, with these advantages it is still necessary, as with traditional long incision surgery, that a fibrin glue be used at the surgical site to hold the tissue together for healing promoting hemostasis and sealing of air leaks. Fibrin in the human body is the product of an activated coagulation system. It is an insoluble protein formed in the extravascular space from fibrinogen by the proteolytic action of thrombin during the normal clotting of blood. 
     Fibrin glue delivery systems that mimic this natural body process exist for traditional long incision surgery. Typically in these systems, the thrombin and fibrinogen are kept in separate containers. When the fibrin glue seal is needed to seal a surgical site, preferably equally amounts of the fibrinogen and thrombin are combined and the enzymatic action of the thrombin on the fibrinogen forms the fibrin. The reaction is nearly instantaneous. Due to the reaction kinetics, both the delivery and mixing of the precursor fibrin components to the wound or surgical site must occur rapidly and accurately before the reaction occurs to form the fibrin. 
     This rapid rate of reactivity to form the fibrin does not typically present difficulties when applied to traditional long incision surgery, but does present a problem in endoscopic surgeries. Sealing a surgical site with a fibrin glue after endoscopic surgery requires delivering the fibrin endoscopically through a small surgical incision, over an enclosed distance underneath the skin, for ultimate delivery to a remote surgical site. Unfortunately, none of the existing fibrin delivery systems appear to be able to accommodate delivery of aerosolized fibrin endoscopically to a remote surgical site. Aerosolized fibrin mixes the two components (thrombin and fibrinogen) more effectively than existing endoscopic delivery systems. The more effective the mixing, the more effective the glue (sealing action). The present invention was designed to satisfy this long felt need of a more effective (fibrin) biologic sealant in endoscopic surgery. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a novel apparatus for delivering aerosolized fibrin endoscopically to a wound. 
     It is another object of the present invention to provide a novel apparatus for delivering aerosolized fibrin endoscopically to a wound having a novel mixing chamber. 
     Yet another object of the present invention is to provide a novel apparatus for delivering fibrin endoscopically to a wound that incorporates a carrier gas (CO 2  or nitrogen, etc.) to convert the fibrin precursor solutions into aerosolized solutions which are mixed more efficiently and create a more effective sealant. 
     Another object of the present invention is to provide a novel apparatus for delivering fibrin endoscopically to a wound that incorporates a specialized mixing chamber for the carrier gas with the separate fibrin precursors. 
     It is another object of the present invention to provide a novel apparatus for delivering fibrin endoscopically to a wound that permits a surgeon to introduce an aerosolized fibrin seal into a remote endoscopic surgical site. 
     Still another object of the present invention is to provide a novel apparatus for delivering fibrin endoscopically to a wound that alleviates the risk of the aerosolized fibrin precursors reacting prematurely to form fibrin while still within the delivery tube which would clog the tube. 
     An additional object of the present invention is to provide a novel apparatus for delivering aerosolized fibrin endoscopically to a wound that carries the fibrin precursor solutions through the delivery tube before they react to form fibrin. 
     In satisfaction of these and related objectives, Applicant&#39;s present invention provides for an apparatus for delivering aerosolized fibrin endoscopically to a wound. Applicant&#39;s invention permits its practitioner to introduce an aerosolized fibrin seal into a remote endoscopic surgical site without the risk of the fibrin precursors combining prematurely within the the delivery tube. Aerosolization provides for better mixing of the fibrin precursors (thrombin and fibrinogen) which creates more effective fibrin for sealing air leaks and hemostatis. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, a perspective view of the preferred embodiment of the present invention is shown. The delivery apparatus  100  has two syringes  101  and  102  for accommodating the fibrin precursors thrombin and fibrinogen, respectively. The syringes  101  and  102  are placed at a variable distance apart. Each syringe  101  and  102  has a cylindrical body  117  with a nozzle  112  at one end and an open base at the other end accommodating a radial extension  121 . Along the length of cylindrical body  117  are graduations  120  to indicate the amount of the respective fibrin precursors introduced into the syringes  101  and  102 . Through the open base of the cylindrical body  117  is inserted a plunger  118  having a compressor  119  at one end and a finger engager  103  at the opposite end. The plunger  118  is slidingly engaged within the cylindrical body  117  in such a way that the outer surface of compressor  119  remains in contact with the inner surface of the cylindrical body  117 . The syringes  101  and  102  can be made of any suitable medical grade material and can be of any size consistent with the necessary application. The plunger  118  is preferably made of a medical grade elastic material such as rubber. 
     The open end of nozzle  112  of both syringes  101  and  102  is situated within and forms a fluid tight connection with one end of first collars  110 . The opposite end of first collars  110  joins with a fluid tight connection to one end of necks  111  which feed with a fluid tight connection into one end of mixing chambers  116 . First collars  110 , necks  111 , and mixing chambers  116  can be made of any suitable medical grade material and can be of any size consistent with the application. 
     Tubes  113  join with a fluid tight connection from the opposite end of mixing chambers  116  into a first Y-junction  114 . First Y-junction  114  terminates in a dual lumen delivery tube  104  having a release nozzle  105  at its opposite end. The dimensions of delivery tube  104  can vary based the application. Tubes  113 , first Y-junction  114 , and delivery tube  104  are constructed of a suitable medical grade material. 
     Up from the top of mixing chambers  116  are one end of arms  122 . Arms  122  terminate in a second Y-junction  115  which connects with a fluid and gas tight connection into third collar  107  at one end. Third collar  107  has dimensions that vary based on the application. A tube  106  is placed within third collar  107  at its opposite end with a fluid and gas tight connection. A source of high pressure gas (nitrogen or carbon dioxide) (not shown) can be connected to the mixing chambers  116  by way of tube  106 . 
     In operating the fibrin delivery apparatus of the present invention, an amount of fibrinogen solution is filled in one syringe  101  and an equal amount of the thrombin solution is filled in the second syringe  102 . The finger engagers  103  of the syringes  101  and  102  are depressed which allows the compressors  119  to exert pressure on the respective fibrin precursor solutions within the syringes  101  and  102  forcing the solutions out through the respective nozzles  112  through first collars  110  and into mixing chamber  116 . At least one unidirectional valve may be placed between the nozzles  112  and the mixing chambers  116  to prevent retrograde flow of the solutions back in to the syringes  101  and  102 . Coincident with this process, nitrogen or carbon dioxide gas from a remote source (not shown) is introduced through tube  106 , past third collar  107 , through arms  122  into mixing chambers  116  containing the respective solutions. At least one unidirectional valve may be placed between the remote source of gas and the mixing chambers  116  to prevent retrograde flow of the solutions back into the remote source. Placement of the arms  122  at between a 45 degree and 90 degree angle from second Y junction  115  may tend to minimize any retrograde flow into the remote source of gas. The high pressure of the gas mixes the gas into the respective solutions aerosolizing them and converting them into separate high pressure aerosols. The high pressure aerosols pass rapidly out of mixing chambers  116  into tubes  113  and past the first Y junction  114  into the dual lumen delivery tube  104  where both aerosol solutions are carried separately then mixed as they exit the tip. 
     Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limited sense. Various modifications of the disclosed embodiments, as well as alternative embodiments of the inventions will become apparent to persons skilled in the art upon the reference to the description of the invention. It is, therefore, contemplated that the appended claims will cover such modifications that fall within the scope of the invention.