in the following detailed description , reference is made to the accompanying drawing figures which form a part hereof , and which show by way of illustration specific embodiments of the invention . it is to be understood by those of ordinary skill in this technological field that other embodiments may be utilized , and structural , as well as procedural , changes may be made without departing from the scope of the present invention . one embodiment of easy drainage catheter assembly 20 according to the present invention is illustrated in fig1 a - 1c . the easy drainage catheter assembly includes trocar 22 , cannula 24 , catheter stiffener 26 , and catheter 28 . although described herein as a preferred device and method for removing fluid collections out of the human body , the embodiment may be utilized to perform other functions such as providing drainage to obstructed drainage systems in body organs such as , for example , the biliary system in the liver or urinary system in the kidney . various components of easy drainage catheter assembly 20 are described below in more detail , and further illustrated in fig2 , 4 a , 4 b , and 5 a - 5 c . as shown in fig2 , trocar 22 includes proximal end 30 , intermediate portion 32 , and distal end 34 . the proximal end is shown attached to conventional male luer connector 36 for rotatably connecting with the proximal end of cannula 24 . distal end 34 forms a sharply pointed tip 38 for inserting through body tissue . the trocar may be formed from a sufficiently hard material such as steel , nitinol , metallic alloy , and the like . by way of non - limiting example , trocar 22 has a diameter of approximately 1 mm , and a length of approximately 19 to 32 cm . however , the diameter and length may vary according to the site of the body cavity or organ inside the human body on which the easy drainage catheter assembly is to be applied . as shown in fig3 , cannula 24 includes proximal end 40 , intermediate portion 42 , and distal end 44 . the proximal end is attached to conventional luer connector 46 , with male end 48 rotatably connecting with the proximal end of the catheter stiffener 26 and female end 50 receiving the male luer connector 36 of trocar 22 . the length of the cannula extending from proximal end 40 to distal end 44 is sized to receive intermediate portion 32 of the trocar 22 such that tip 38 of the trocar extends as shown in fig1 a , for instance , 1 - 3 mm beyond distal end 44 of the cannula 24 . the central lumen ( not shown ) of the cannula is appropriately sized to slideably receive the trocar and is preferably about 1 mm in diameter , but may vary depending on the size of the trocar . as described further below , cannula 24 provides a mechanism for catheter stiffener 26 and catheter 28 to slideably insert over when entering into the human body , and also permits obtaining a fluid specimen from the fluid collection by aspiration . the cannula may be made of a hard material such as steel , nitinol , or metallic alloy , among others . by way of non - limiting example , cannula 24 has a length of approximately 19 - 32 cm . however , the length of the cannula may vary according to the site of the body cavity or organ inside the human body on which the easy drainage catheter assembly is to be applied . as shown in fig4 a and 4b , catheter stiffener 26 includes proximal end 52 , intermediate portion 54 , and distal end 56 . the proximal end is attached to a conventional luer connector 58 with male end 60 rotatably connecting with the proximal end of catheter 28 , and female end 62 receiving male end 48 of luer connector 46 of cannula 24 . catheter stiffener 26 extends from proximal end 52 to distal end 56 , and the outer diameter is sized to fill up the lumen of catheter 28 , which will be further illustrated below . by way of non - limiting example , the outer diameter of the catheter stiffener is about 1 . 5 - 2 . 5 mm , but may vary depending on the size of the catheter . the length of catheter stiffener 26 covers a proximal portion of cannula 24 , and typically remains outside the human body when trocar 22 is inserted into the body cavity . the length of the distal portion of the cannula not covered by catheter stiffener 26 varies , for instance , from 7 - 13 cm , depending on the site of the fluid collection . distal end 56 of the catheter stiffener may be tapered to match with the tapered distal end of the catheter . the central lumen ( not shown ) of catheter stiffener 26 is appropriately sized to slideably receive cannula 24 and includes a diameter of about 1 . 5 mm or less , but may vary with the size of the cannula . the catheter stiffener may be formed from a stiff material such as , for example , nylon , polyester , or silicon . by way of non - limiting example , the catheter stiffener may have a length of approximately 13 - 19 cm . however , the length may vary according to the site of the body cavity or organ inside the human body on which the easy drainage catheter assembly is applied . as shown in fig5 a and 5b , catheter 28 includes proximal end 64 , intermediate portion 66 , and distal end 68 . the proximal end is attached to a conventional female luer connector 70 and receives male end 60 of luer connector 58 of the catheter stiffener . catheter 28 extends from proximal end 64 to distal end 68 . the diameter of the central lumen ( not shown ) of the catheter is appropriately sized to slideably receive the catheter stiffener . distal end 68 forms tapered tip 72 , which reduces resistance encountered when entering body tissue , thereby making it easier to insert over the cannula into the body tissue . a plurality of longitudinally spaced ports or openings 74 are formed in intermediate portion 66 , proximal to tapered distal tip 72 , and at axially spaced locations . each opening directly communicates with the central lumen of the catheter for the drainage of fluid . radiopaque markings may be formed along intermediate portion 66 at predetermined locations . these marking assist in fluoroscopically determining the positioning of the catheter . catheter 28 may be formed from soft pliable material such as polyurethane . to enhance and maintain the stiffness of intermediate portion 66 during insertion over cannula 24 into the human body , and to prevent the soft material of catheter 28 from bunching up , intermediate portion 54 of catheter stiffener 26 extends lengthwise to fill up the space between catheter 28 and cannula 24 . note that intermediate portion 54 of the catheter stiffener includes an outer diameter that is approximately sized to slideably insert into the central lumen of catheter 28 . stiffening catheter 28 eliminates the tendency of the soft material to bunch up , which would make it difficult for the catheter to be inserted into body tissue and cause trauma to the patient . by way of non - limiting example , catheter 28 has a diameter of 2 - 4 mm , and a length of approximately 13 - 19 cm . however , the diameter may vary with the body cavity or organ to which the easy drainage catheter assembly is applied , and the length may vary according to the site of the body cavity or organ inside the human body . fig1 a shows the pre - assembled easy drainage catheter assembly 20 ready for insertion as a unit . trocar 22 , cannula 24 , catheter stiffener 26 , and catheter 28 are coupled together by the luer connectors located at the proximal end of the assembly . fig6 , 7 a - 7 c , and 8 - 10 illustrate a procedure using the easy drainage catheter assembly 20 to drain body fluid from a body cavity . as shown in fig6 , a first step is to insert the distal portion of trocar 22 and cannula 24 into the body cavity or the drainage system of the organ to be drained . catheter stiffener 26 and catheter 28 remain outside the human body . as shown in fig7 a , trocar 22 is then detached from cannula 24 by disengaging male luer connector 36 of the trocar and female end 50 of luer connector 46 of the cannula , and slideably retrieving trocar 22 out of the lumen of cannula 24 . a specimen may then be obtained from the fluid collection in the body cavity by aspiration through the lumen of cannula 24 . this step is to ensure that the cannula has been inserted into the desired location . otherwise , the previous steps may be repeated . in that case , catheter stiffener 26 and catheter 28 have not yet been inserted into the body tissue , which saves the body tissue from being further torn apart by the catheter stiffener and the catheter of larger diameter . if fluid collection is within the organ , conventional guide wire 78 may be slideably inserted through the lumen of cannula 24 and into the drainage system within the organ , such as that shown in fig7 b . the guide wire often contains curved tip 80 , which is useful for moving through curved regions of an organ duct . as shown in fig7 b , conventional torque device 82 is secured on guide wire 78 , outside the human body . the torque device is useful for rotating the guide wire and turning curved tip 80 , which enables the guide wire to enter the desired duct at cross sections of multiple ducts . torque device 82 may be secured along guide wire 78 at a convenient position for the operator to control the guide wire . according to an embodiment , the torque device may include male luer connector 84 for securing with female end 50 of luer connector 46 of the cannula . as shown in fig7 c , the operator can therefore hold cannula 24 and guide wire 78 together in a stable position by holding one device . the operator is not required to handle these two devices separately during the insertion of catheter 28 . guide wire 78 acts as a guiding agent to facilitate the insertion of catheter 28 , which will be described below . as shown in fig8 , female end 62 of the luer connector of catheter stiffener 26 is then disengaged from male end 48 of the cannula . catheter 28 and catheter stiffener 26 are then inserted as a unit into the body cavity over cannula 24 . distal end 56 of the catheter stiffener may extend distally beyond distal end 44 of the cannula to support catheter 28 if the catheter is to be further inserted to reach the fluid collection in the body cavity . as catheter stiffener 26 is made of a relatively stiff material , it typically does not extend more than 0 . 5 mm from cannula distal end 44 . the catheter stiffener may be covered with an extended length of catheter 28 , when it is advanced within the body , to prevent the catheter stiffener from accidentally damaging the soft tissue of the body cavity . as shown in fig7 c and 9 , female luer connector 70 of the catheter is disengaged from male end 60 of the stiffener . intermediate portion 66 of the catheter is inserted beyond distal end 56 of catheter stiffener 26 to reach into the fluid collection , thus permitting openings 74 to contact the fluid collection . if fluid collection is present within the organ , intermediate portion 66 may be further inserted over guide wire 78 , and into the drainage system within the organ . as described above and shown in fig7 c , the locking of guide wire 78 and cannula 24 by torque device 82 frees the operator from holding the guide wire during the insertion of the catheter . the operator holds the cannula in a stable position and controls the insertion of the catheter , without separately holding the guide wire in place . as shown in fig1 , cannula 24 , guide wire 78 if used , and catheter stiffener 26 are slideably retrieved from catheter 28 . intermediate portion 66 of the catheter is fixed externally onto the skin surface with a fixation device or stitches . finally , female luer connector 70 is connected to a suction device or a connection tube of a drainage bag for the drainage of the abnormal fluid . as shown in fig1 a , each luer connector may include gripper wings 99 to make it easier for the operator to connect or disconnect the luer connectors from each other . each luer connector may have a different number , shape , or color of gripper wings so that the operator can distinguish the various components of the easy drainage catheter assembly . by way of non - limiting example , the female luer connector of catheter 70 contains two gripper wings , the luer connector of catheter stiffener 58 contains three gripper wings , the luer connector of cannula 46 contains four gripper wings ; the male luer connector of trocar 36 contains five gripper wings , and torque device 82 contains six gripper wings . the present invention provides a unique , simplified approach for placement of a drainage catheter . time - consuming and redundant steps utilized in conventional procedures , such as the repeated insertion of dilator sheaths , are eliminated . the insertion step of the trocar and cannula may be separated from the insertion step of the catheter so that the device will encounter less resistance when entering into the human body . the present invention also reduces the likelihood of mis - positioning the drainage catheter since the specimen of the fluid collection can be obtained before the actual drainage . such step is taken without the catheter being inserted into the body tissue , which would further tear off the body tissue . this two - step approach therefore eliminates unnecessary insertion of the catheter when the trocar is found mis - positioned upon testing of the fluid specimen . the patient need not suffer trauma encountered when the catheter is unnecessarily inserted into the body tissue . while the invention has been described in detail with reference to disclosed embodiments , various modifications within the scope of the invention will be apparent to those of ordinary skill in this technological field . it is to be appreciated that features described with respect to one embodiment typically may be applied to other embodiments . therefore , the invention properly is to be construed only with reference to the claims .
a drainage catheter assembly for the insertion of a drainage catheter percutaneously includes a trocar , a cannula , a catheter stiffener , and a catheter . the trocar includes a distal pointed end , a proximal end , a uniform cross - sectional shape between the distal pointed end and the proximal end , and a means located at the proximal end for releasably connecting with a cannula . the cannula may include a distal end , a proximal end , a cannula lumen extending therethrough , and a means located at the proximal end for releasably connecting with the trocar and catheter stiffener . the catheter stiffener includes a distal end , a proximal end , a body portion comprising stiff material , a catheter stiffener lumen extending therethrough , and a means located at the proximal end for releasably connecting with the cannula and catheter . the elongated catheter includes a distal end containing a tapered tip , a proximal end , a catheter lumen extending therethrough , and a means for releasably connecting with the catheter stiffener .