Abstract:
An apparatus for making and administering two non-homogenous liquids to target tissue includes a spray comprising two syringes for containing the first and second non-homogenous liquid where the syringes are adapted to be removably coupled to an applicator. The applicator includes a pair of elongated tubes each having a tubular sheath at a proximal end, a distal end and a lumen in which the pair of elongated tubes are disposed. The apparatus includes a regulator module having an inlet port adapted for connection to a source of gas under pressure and a gas outlet port adopted for connection to the gas inlet port of the sheet. A vent gas inlet port is adapted for connection to a vent port of an endoscopic cannula where the regulator vents a quantity of gas from the endoscopic cannula approximately equal to a quantity of gas introduced at the gas inlet port of the sheet.

Description:
BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     This invention relates generally to endoscopic application of bio-materials to target tissue in the course of a laparoscopic surgical procedure, and more particularly to an endoscopic spray applicator system design to mix two non-homogeneous liquids and to allow the resulting mixture to be applied thinly and evenly by spraying, on a difficult to reach treatment site, such as subcutaneously or within the body through an endoscopic cannula. 
     II. Discussion of the Prior Art 
     Tissue adhesives have long been recognized for their potential to hasten wound healing, reduce post-operative complications and decrease the need for drains following surgery. Typically, such adhesives have been prepared on the day of surgery from the patient&#39;s own blood. A quantity of blood would be drawn from the patient just prior to surgery and in a centrifugation process, natural clotting factors are isolated and concentrated for application on to the surgical wound while the remaining red blood cells were then reinjected or autotransfused back into the patient&#39;s bloodstream. 
     Fibrin sealant is a tissue adhesive that mimics the body&#39;s own natural clotting mechanism. Two basic components make up fibrin sealant, namely, fibrinogen and thrombin. Because fibrin sealant is derived from blood products, it is associated with viral disease transmission. To reduce the risk of viral-disease transmission from pooled plasma sources of fibrinogen, various viral inactivation methods are employed in commercial fibrin sealants. Blood banks often produce fibrinogen from screened, single-donor sources or use autologous fibrinogen. Currently, bovine thrombin is most often used, although methods for producing human thrombin or recombinant thrombin are being developed. Fibrin sealants can be used in a variety of surgical applications to enhance hemostasis, to seal tissues, to close fistulas and to deliver biologics or drugs. 
     When fibrin and thrombin are made to mix, a coagulum is formed where the platelets interdigitate with the forming fibrin web, developing a gel with adhesiveness and strength materially greater than the plasma alone. Because of the rapid clotting propensity, it is necessary to keep the two liquid constituents separated and only mixed at the distal end of the applicator. Numerous tissue adhesive applicators have been developed, such as those described in U.S. Pat. No. 4,040,420 to Speer, U.S. Pat. No. 4,359,049 to Redl, U.S. Pat. No. 4,733,666 to Eibl, U.S. Pat. No. 4,826,048 to Skorka, U.S. Pat. No. 4,874,368 to Miller, U.S. Pat. No. 4,902,281 to Avoy, U.S. Pat. No. 4,978,336 to Capozzi, U.S. Pat. No. 5,368,563 to Lonnemann and U.S. Pat. No. 5,474,540 to Miller. A variety of these types of applicators exist including internal swirl or mixing chamber applicators and external combining applicators, such as external swirl applicators and external spray or stream overlapping applicators. 
     The Skorka &#39;048 patent, the Capozzi &#39;336 and &#39;315 patents concerns swirl or other pre-ejection mixing applicators where mixing is performed by squirting or otherwise forcing the two non-homogeneous fluids into a swirl or other mixing chamber where the fluids mix to some degree based upon turbulence in the swirl chamber and the material properties and are thereafter ejected from the applicator. The mixing occurs inside the applicator and, thus, time is critical, as it must be ejected prior to coagulation. In certain applications, such as where one or more of the solutions or fluids is thick or high viscous, internal swirling results in only marginal or partial mixing, while in other applications, such as where all of the solutions or fluids are thin or not highly viscous, substantial and effective mixing occurs. 
     In contrast, the applicators described in the Speer &#39;420, the Miller &#39;368 and the Avoy &#39;281, the Lonnemann &#39;563 and the Miller &#39;540 patents are external combining applicators. Here, the two solutions are brought into contact with one another at the point of use or functional tissue adhesive creation. External combining eliminates premature mixing problems. However, with many external combining applicators, thorough mixing of the solutions does not occur and, instead, only adjacent portions of the solutions mix or combine well large percentages remain unmixed or uncombined. This results in inefficient and somewhat uncontrolled coagulation. The Lonnemann &#39;563 patent owned by applicant&#39;s assignee is considered to be a significant advance in external combining applicators. It provides an external swirling pattern where the two fluids overlap one another resulting in improved fluid mixing. 
     In copending application Ser. No. 10/863,631, filed Jun. 8, 2004, and entitled “Spray Applicator”, there is described a medical fluid delivery system which expels two liquid components, at least one of which is reactive, from separate syringes while simultaneously releasing a pressurized fluid, such as a compressed gas, around, adjacent to or proximate the reactive components resulting in thorough mixing of the reactive components as well as propulsion thereof in a commingled stream onto a surgical site. The teachings of such application are hereby incorporated by reference. The teachings of that application, however, do not address a further problem where such a gas propelled stream of reactive liquids, such as fibrin and thrombin are to be used in a laparoscopic procedure. 
     In laparoscopic procedures, a series of holes are surgically created in the abdominal wall with one to accommodate a camera and others to accommodate a cannula through which a working instrument, such as a laparoscopic scissors, forceps are inserted for grasping and cutting target tissue. It is common practice to insufflate the abdominal cavity by introducing a gas through one of the trocars, thereby expand the abdominal cavity to aid in viewing and manipulating internal organ structures. The trocars include a self-closing seal for preventing loss of insufflation gas while allowing penetration by the surgical instruments employed. The pressure employed in insufflating is generally about 15 mmHg and the introduction of additional gas by way of a laparoscopic spray applicator could result in over-inflation and distension of the abdominal wall. Means must, therefore, be provided to insure that this does not occur. 
     SUMMARY OF THE INVENTION 
     The present invention provides an apparatus for mixing and administering two non-homogeneous liquids to target tissue in an endoscopic procedure where the apparatus includes a spray set comprising a pair of syringes for containing the first and second liquids where the syringes are adapted to be removably coupled to an applicator. The applicator includes a pair of elongated tubes, each having a proximal end for attachment to the two syringes and a distal end. The pair of elongated tubes is, in turn, contained within the lumen of a tubular sheath that also has a proximal end and distal end. Affixed to the distal end of the elongated tubes and the sheath is a replaceable spray tip. The sheath also has a gas inlet port at its proximal end that is in fluid communication with the sheath lumen. 
     The spray set is used in combination with a regulator module. The regulator module has a regulator input port adapted for connection to a source of gas under relatively high pressure, a gas outlet port adapted for connection to the gas inlet port of the sheath and a vent gas inlet port adapted for connection to a vent port of an endoscopic cannula. The regulator module is operative to vent a quantity of gas from the endoscopic cannula approximately equal to the quantity of gas introduced through the gas inlet port of the sheath to thereby preclude the buildup of pressure within the abdominal cavity during spray application of the two non-homogeneous liquids to target tissue within the abdominal cavity. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The foregoing features, objects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, especially when considered in conjunction with the accompanying drawings in which like numerals in the several views refer to corresponding parts. 
         FIG. 1  is a perspective view of the gas-assisted endoscopic tissue adhesion applicator system of the present invention; 
         FIG. 2  is a cross-sectional view of the spray set used in the system of  FIG. 1 ; 
         FIG. 3  is an enlarged view of the replaceable spray tip used with the spray set of  FIG. 2 ; 
         FIG. 4  is a partial isometric view of the spray set with liquid dispensing syringes attached used in combination with a trocar during an endoscopic procedure; and 
         FIG. 5  is a schematic pneumatic diagram of the regulator module illustrated in  FIG. 1 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIG. 1 , there is indicated generally by numeral  10  a gas-assisted endoscopic tissue adhesive applicator system. It is seen to include a regulator module  12  having an input port  14  that is adapted to be connected by a length of tubing  16  to a source of gas under pressure. In most operating room settings, sterile pressurized gas is available at a wall outlet to which the connector  18  may be joined. Typically, the gas pressure available at the wall outlet may be in excess of 100 psi. Also connected to the regulator module  12  is a pneumatic control valve, here shown as a foot actuated valve  20 . It is connected through a pneumatic line  22  to port  24 . 
     As will be explained in greater detail herein below, a manually rotatable knob  26  is mounted on a front face of the regulator module  12  and may be used to adjust the rate of flow in liters-per-minute of gas exiting the gas outlet port  28  of the regulator module  12 . While flow may be adjustable from 0-10 liters/minute, a typical range for the spray applicator may be from 1-2 liters/minute. Disposed alongside the adjustment knob  26  is a flow indicator  30  of a conventional design incorporating a pith ball within a transparent tube having scale markings associated therewith where the height of the ball within the tube is an indication of the flow rate setting. 
     Also visible on the front face of the regulator module  12  is a pressure gauge  32 , allowing the user to monitor to assure that the air pressure maintained by the regulator is within desired limits. 
     The system  10  further includes a spray set indicated generally by numeral  34 . Referring to  FIG. 2 , it is seen to include a pair of elongated tubes disposed in close, side-by-side relationship and of which only tube  36  is seen in the cross-sectional view of  FIG. 2 . The proximal end of the pair of tubes are joined to Luer fittings  38  and  40  allowing attachment of the spray set  34  to a pair of hypodermic syringes  42  and  44  ( FIG. 4 ). The two syringes may be of differing volumes to accommodate a desired ratio of the liquids to be combined. 
     The pair of elongated tubes, as at  36 , is preferably hypodermic stock and may be of the same internal diameter or, alternatively, may also be of a differing diameter. The elongated tubes, as at  36 , are preferably welded to one another and are surrounded by a tubular sheath  46  with a clearance space  48  therebetween. The sheath may be of stainless steel or other suitable material. The distal ends of the pair of tubes  36  are designed to extend beyond the distal end of the surrounding sheath  46 . The Luer fittings  38  and  40  are mounted on a molded plastic hub  50  along with check valves  51  and  53 . The check valves serve to prevent back flow into the syringes. The bifurcated legs  52  and  54  ( FIG. 4 ) each include a central bore in fluid communication with the outlets of the syringes  42  and  44  and they individually lead to the pair of elongated tubes of hypodermic stock. As such, liquid ejected from the syringe  42  remains separated from the liquid ejected from syringe  44  and do not mix with one another until reaching the distal tip  56  of the spray set. Because the distal ends of the pair of hypo-tubes  36  extend beyond the distal end of the sheath, cleaning of the spray set is facilitated. 
     Affixed to the outer sheath  46  of the spray set is a Y-connector  58  ( FIGS. 2 and 4 ) which also includes a Luer fitting  60  for accommodating attachment of a length of plastic tubing  62  that is adapted to be connected to the gas outlet port  28  of the regulator module  12 . Thus, air under pressure can be made to flow from the outlet port  28  through a filter device  64  and the tubing  62  and thence through the Y-connector  58  and the lumen  48  of the sheath  46  to reach the distal end of the spray set. 
     Referring next to  FIG. 3 , there is illustrated a replaceable spray tip  66  that is adapted to be removably attached to the distal end  68  of the sheath  46  by means of a threaded coupling. The interior of the spray tip  66  is designed to blend the two liquid made to flow through the elongated hypodermic stock tubes  36  with air or other suitable gas coming through the regulator to create a vortex generating an aerosol-like spray or mist exiting the tip opening  70  of the replaceable spray tip  66 . The replaceable tips are preferably made from a radiopaque polymer. 
     Turning momentarily again to  FIG. 4 , the line  72  represents the abdominal wall of a patient undergoing endoscopic surgery. The spray set  34  is shown as having the sheath  46  inserted through an insufflation seal  74  affixed to the end of a trocar  76  that is shown as penetrating through the abdominal wall  72 . The seal  74  is adapted to prevent escape of insufflation gas that is delivered through a trocar to expand the abdomen and provide better access to internal organs being operated upon. 
     In accordance with the present invention, the trocar  76 , and especially the seal fitting  74 , has a gas exit port  78  with a Luer fitting  80  allowing a length of plastic tubing  82  to be affixed thereto. As shown in  FIG. 1 , the tubing  82  is adapted to be connected to the regulator module  12  at a vent gas inlet port  84 . 
     Referring next to the schematic drawing of the regulator module illustrated in  FIG. 5 , a pressurized gas is applied to the input port  14  of the regulator assembly as already described and it is applied to a self-relieving pressure regulator  86  which is set at the factory to drop the pressure from the level applied to the gas inlet port  14 , e.g. 200 psi, to a predetermined lower value, e.g., 20 psi. A gauge  32  is coupled to the regulator to provide a visual indication to a user that the pressure output from the regulator  86  is within prescribed limits. 
     The output from the regulator on line  88  is presented to a pressure limit safety valve  90  which functions to prevent gas pressure in the line  88  from exceeding a second predetermined level, e.g., 25 psi, in the event that the self-relieving pressure regulator  86  should fail. 
     Line  88  also leads to a two-way valve  92  contained within the foot switch assembly  20 . Manual actuation of the foot switch opens the valve  92  permitting gas flow through the return line  94  to which a pilot-actuated, two-position, five-way pneumatic valve  96  is connected. When the pilot valve  98  senses pressure in the line  94  occasioned by the opening of the valve  92 , the gas first flows through a flow meter  30  and then through the valve  96  to the gas outlet port  28 . 
     As earlier mentioned, the flow of gas through the gas outlet port  28  is typically about 1-2 liters/minute and is filtered by a 0.2 micron filter unit  64  and then flows through the tubing  62  to the lumen  59  in the hub  58 . At the same time that the footswitch  20  is depressed to produce this gas flow, the medical professional involved will slowly depress the plungers on the syringes  42  and  44  simultaneously to thereby flow the two non-homogeneous liquids (fibrin and thrombin) contained within the syringes down through the lumens of the elongated tubes  36  causing the two liquids to blend with the pressurized air flowing down the sheath  46  in the replaceable spray tip  66  and exit as an aerosol that can be directed against target tissue within the patient&#39;s abdominal cavity. 
     As those skilled in the art appreciate, during laparoscopic surgery it is common practice to insufflate the abdominal cavity to thereby move the abdominal wall away from internal organs on which the surgical procedure is being directed. The insufflation pressure is typically about 15 mmHg. In order to avoid a pressure increase due to the introduction of the gas through the spray set, the trocar  74  ( FIG. 4 ) used in combination with the spray set of the present invention includes a vent port  78  that is in fluid communication with the interior of the abdominal cavity via a lumen in the trocar  74 . A length of plastic tubing  82  connects to the vent port  78  of the trocar to the vent gas inlet port  84  of the regulator module  12  by way of a 0.5 micron filter in the vent line. So long as the footswitch  20  is depressed to open the control valve  92 . The valve  96  also opens to apply the gas to the spray set. The pilot-controlled, pneumatic valve  96  simultaneously opens a path, including lines  100  and  102 , to thereby flow the vented gas at a rate of 1-2 liters/minute to the atmosphere. With this arrangement, the same amount of gas introduced into the abdominal cavity due to the application of the spray of tissue adhesive is simultaneously exhausted, preventing a buildup of pressure within the abdominal cavity. The two sides of the valve  96  are mechanically interlocked to prevent one line from opening without the other. The vent line is normally closed to minimize insufflator gas usage when the footswitch is not depressed. 
     This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices, and that various modifications, both as to the equipment and operating procedures, can be accomplished without departing from the scope of the invention itself.