Abstract:
A medical device comprises a needle configured for insertion into a body and defining a needle lumen extending therethrough from a proximal end opening to a distal end opening and a handle connected to a proximal end of the needle and including a stylet receiving lumen therein, the stylet receiving lumen being open to a proximal end of the needle lumen. The medical device also comprises a stylet movable between a retracted configuration in which a distal end of the stylet is received within the stylet receiving chamber and an extended configuration in which the distal end of the stylet is received within the distal opening of the needle lumen sealing the distal opening, wherein, when withdrawn proximally into the stylet receiving lumen, the stylet is coiled within the chamber.

Description:
PRIORITY CLAIM 
       [0001]    The present application claims the priority to the U.S. Provisional Application Ser. No. 61/245,364, entitled “EUS-FNA Stylet Withdrawal into Handle” filed on Sep. 24, 2009. The specification of the above-identified application is incorporated herewith by reference 
     
    
     BACKGROUND 
       [0002]    Biopsies may be performed via Endoscopic Ultrasound Fine Needle Aspiration (“EUS-FNA”) to obtain cells or small samples of tissue from, for example, the breast or liver for cytology studies, endoscopy or oncology. With current EUS-FNA devices, a stylet is inserted through the lumen of a needle to the distal end thereof to prevent tissue from entering the needle as the needle passes through tissue along an insertion path before a target site is reached. When the needle has reached the target site, the stylet is withdrawn proximally from the device to open the lumen. The needle is then inserted into the target tissue and negative pressure may be applied therethrough to aspirate sample tissue from the distal end of the needle further into the lumen. After the sample has been obtained and the needle has been removed from the body, the stylet is passed distally through the lumen to push the sample tissue out of the distal end of the needle (e.g., onto a slide or into another collection area). In many instances, EUS-FNA devices yield samples that are too small, which are contaminated during the biopsy procedure or which are otherwise flawed to the extent that thorough analysis and diagnosis is not possible. In these cases, the tissue must be resampled increasing the time and expense associated with the EUS-FNA procedure. Furthermore, present EUS-FNA devices require removal of the stylet in order to receive a biopsy sample. This withdrawal can cause kinking of the stylet and may result in the stylet becoming unsterile, preventing reinsertion thereof into the EUS-FNA device. In such cases, a new EUS-FNA device must be employed to acquire further biopsy samples. 
       SUMMARY OF THE INVENTION 
       [0003]    The present invention is directed to a medical device comprises a needle configured for insertion into a body and defining a needle lumen extending therethrough from a proximal end opening to a distal end opening and a handle connected to a proximal end of the needle and including a stylet receiving lumen therein, the stylet receiving lumen being open to a proximal end of the needle lumen. The medical device also comprises a stylet movable between a retracted configuration in which a distal end of the stylet is received within the stylet receiving chamber and an extended configuration in which the distal end of the stylet is received within the distal opening of the needle lumen sealing the distal opening, wherein, when withdrawn proximally into the stylet receiving lumen, the stylet is coiled within the chamber. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  is a partial cross-sectional view of a device according to the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0005]    The present invention, which may be further understood with reference to the following description and the appended drawings, relates to an apparatus and method for obtaining tissue samples and, more particularly relates to EUS-FNA devices. The needle design of the present invention which may be used in substantially all procedures employing EUS-FNA devices further increases the efficacy of EUS-FNA procedures by permitting the procurement of tissue samples from a living body without removing the stylet from the device. 
         [0006]    Devices and methods according to the present invention employ an FNA device comprising a stylet which, when retracted proximally thereinto, assumes a storage configuration such as a coiled configuration within a handle of the FNA device eliminating the need to remove the stylet completely from the FNA device when a sample is to be obtained. In this manner, the stylet may be easily retracted to a proximal portion of a needle without having to remove the stylet from the FNA device altogether. It is noted that the use of the term distal herein refers to a direction approaching a target site in a patient in an operative configuration and the term proximal refers to a direction approaching a user of the device (e.g., a physician) with a proximal portion of the device remaining external to the patient. 
         [0007]    As shown in  FIG. 1 , a device  100  according to an exemplary embodiment of the present invention for use with an EUS-FNA actuation mechanism (not shown) comprises an elongated hollow body  102  with a puncturing point  104  at a distal end thereof. It is noted however, that the device  100  may take any other shape and may also comprises a blunt distal end without deviating from the scope of the present invention. The elongated body  102  may be composed of any of a variety of suitable materials known in the art such as, for example, stainless steel and nitinol. The elongated body  102  includes a first lumen  106  extending therethrough to a distal opening  108  at the puncturing point  104 . A handle  110  formed at a proximal end of the body  102  and having an outer diameter greater than an outer diameter of the elongated body  102  remains outside the body during use. The handle  110  may comprise a second lumen  112  extending therethrough and open to the first lumen  106 , a diameter of the second lumen  112  being substantially equivalent to or greater than a diameter of the first lumen  106 . In one embodiment, the second lumen  112  follows a substantially coiled path through the handle  110  and may be formed with any number of turns suitable to accommodate a required length of the stylet  120  therethrough. The handle  110  may be integrally formed with the elongated body  102  or, alternatively, may be bonded thereto using any known bonding technique including gluing, insert molding and other permanent or temporary fixation techniques. In the embodiment shown, the handle  110  is connected to the elongated body  102  via a tapered portion  118 . It is noted however, that the part of the elongated body  102  which remains outside the body during use may take any shape as would be understood by those skilled in the art. The device  100  also comprises a stylet  120  configured to seal the first lumen  106  extending through during an initial penetration into target body tissue, the stylet  120  minimizing the entry of blood, tissue, etc. into the first lumen  106  before a target sampling site has been reached, as those skilled in the art will understand. An exemplary stylet  120  according to the present invention can be formed of a material known in the art including, but not limited to Nitinol, stainless steel, elgiloy, titanium, tantalum and polymers. The stylet  120  may have shape-memory properties as would be understood by those skilled in the art, the stylet  120  being formed to assume a substantially coiled memorized shape. In such an embodiment, the second lumen  112  may be formed with a substantially cylindrical shape instead of the substantially coiled shape of  FIG. 1 , an outer diameter of the coiled shape of the stylet  120  being dimensioned to frictionally engage an inner wall of the second lumen  112 . It is further noted that the handle  110  may also be formed without a second lumen  112 . Rather, the handle  110  may be formed as a hollow substantially cylindrical element having a substantially cylindrical hollow core. In this embodiment, the stylet  120  may be retracted into the handle  110  within which it will assume its shape-memorized coiled configuration, as those skilled in the art will understand. In yet another embodiment of the present invention, the handle  110  may be formed with a grooved patterns molded on an inner wall thereof, the pattern configured to guide the stylet  120  into a retracted (i.e., coiled) configuration. An inner wall of the first lumen  106  and the handle  110  be provided with a hydrophilic coating or other biocompatible lubricious coating to ease insertion of the stylet  120  therethrough. 
         [0008]    An outer diameter of a distal portion of the first lumen  106  is only slightly larger than an outer diameter of the stylet  120  so that the stylet  120  substantially seals the first lumen  106  when it is advanced to the distal end of the first lumen  106 . In an alternate embodiment, a distal tip of the stylet is of a higher durometer than a proximal portion thereof in order to maintain an overall flexibility of the stylet  120  while still occluding the distal end of the first lumen  106 . In one embodiment, the increased durometer portion of the stylet is greater than approximately 2.54 cm. in length, although this value may be changed to affect the flexibility of the stylet accordingly. In an exemplary embodiment of the invention, the inner diameter of the first lumen  106  is substantially constant. In another embodiment, however, the inner diameter of the first lumen  106  may increase at a point proximal of the distal end of the first lumen  106  to house sampled body tissue and facilitate aspiration. Such a device is disclosed in U.S. Provisional Application No. 61/235,465 entitled “Flared Needle for EUS Fine Needle Aspiration Device” filed Aug. 20, 2009, the entire contents of which are incorporated herein by reference. The second lumen  112  is substantially cylindrical and forms a central opening through which the stylet  120  may be retracted. A proximal portion of the first lumen  106  housed within the handle  110  comprises a Y-adaptor leading to a third lumen  114 . The third lumen extends out of the handle  110  and comprises an opening  116  at a proximal end thereof for the connection with a syringe (not shown) or other source of aspiration. The opening  116  may be formed with a seal (not shown) to prevent the entry of foreign matter thereinto when not connected to a source of aspiration. The first lumen  106  may terminate within the handle  110  at a location proximal of an opening  118  of the third lumen  114 , a proximal end of the first lumen  106  further comprising a valve  117  such as a touhy-borst valve. The touhy-borst valve  117  may be configured to maintain a position of the stylet  120  within the first lumen  106  while permitting advancement and retraction thereof. Alternatively, any other suitable valve may be used in place of the touhy-borst valve  117  including, but not limited to duckbill valves, gel-filled valves, foam-filled valves, ball valves and stopcocks. Accordingly, although portions of the stylet  120  received within the first lumen  106  are constrained to a substantially linear arrangement, portions of the stylet  120  which are drawn proximally into the second lumen  112  assume the coiled shape defined by the coils of the second lumen  112 . In one embodiment, a pitch of the coils of the second lumen  112  may preferably be selected to be substantially equal to a diameter of the stylet  120  so that adjacent turns of the coil contact one another and a length of the stylet  120  which may be received within the second lumen  112  is maximized. Furthermore, a length of the second lumen  112  is preferably chosen so that, when the stylet  120  is fully retracted proximally, the distal end of the stylet  120  is withdrawn into the second lumen  112  proximal of the third lumen  114 . This moves the distal end of the stylet  120  out of the first lumen  106  permitting the passage of fluids and/or tissue through the third lumen. A proximal end of the third lumen  114  may be connected to a source of negative pressure such as a vacuum pump, syringe, etc. to aspirate sampled tissue through the first lumen into the third lumen  114 . A seal (not shown) may also be provided at this proximal end to ensure proper transfer of a vacuum pressure therethrough. 
         [0009]    The stylet  120  may be advanced and retracted within the device  100  by actuating an actuating mechanism (not shown) located on a proximal end of the handle  110 . The actuating mechanism (not shown) may be formed of a design including, but not limited to, a rotatable portion (not shown) on the handle  110 , rotation of the rotatable portion causing distal advancement or proximal retraction of the stylet  120  or a motorized component configured to control movement of the stylet  120 . In one embodiment, the actuating mechanism may be a ratchet mechanism or pulley to permit linear actuation of the stylet  120 , as those skilled in the art will understand. In an operative configuration, the actuating mechanism is configured to advance the stylet  120  out of the second lumen  112  into the first lumen  106  and through the first lumen  106  until a distal end of the stylet  120  is received in the distal opening of the first lumen  106 . When a target tissue site has been reached, the stylet  120  is retracted so that a distal end thereof is located proximal to the opening  118  of the third lumen  114  so that a source of negative pressure applied to the third lumen  114  permits sampling of tissue or other biological matter thereinto. It is noted that although the present invention has been described with respect to a coiled path of the second lumen  112  through the handle  110 , the second lumen  112  may follow any path through the handle without deviating from the scope of the present invention. 
         [0010]    It is noted that, although the present invention has been described with reference to specific exemplary embodiments, those skilled in the art will understand that various modifications and changes may be made to the embodiments. For example, the exemplary embodiments of the present invention call for a path of the stylet through the handle that is longer than a longitudinal length of the handle itself to permit retraction of the stylet thereinto without removing the stylet from the body. Thus, the stylet may follow any path through the handle without deviating from the scope of the present invention. The specifications are, therefore, to be regarded in an illustrative rather than a restrictive sense.