Abstract:
A needle assembly comprises an outer cannula and an inner cannula. The outer cannula and the inner cannula have complementary tissue receiving apertures. A tissue piercing tip is secured relative to one or both of the inner cannula or the outer cannula. A cutter is slidably disposed in the inner cannula. The cutter is configured to sever tissue protruding through the transverse apertures. A hub releasably secures at least part of the needle assembly relative to the body of a biopsy device.

Description:
PRIORITY 
     This application is a continuation of U.S. Non-Provisional patent application Ser. No. 12/437,961, entitled “Method of Manufacturing a Needle Assembly for Use with a Biopsy Device,” filed May 8, 2009, the disclosure of which is incorporated by reference herein, and which is a divisional of U.S. Non-Provisional patent application Ser. No. 11/027,120, entitled “Method of Manufacturing a Needle Assembly for Use with a Biopsy Device,” filed Dec. 30, 2004, the disclosure of which is incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention is related generally to biopsy devices and, more particularly, to an improved process of manufacturing a needle assembly for use with a biopsy device for acquiring a tissue sample. 
     BACKGROUND OF THE INVENTION 
     The diagnosis and treatment of patients with cancerous tumors, pre-malignant conditions, and other disorders has long been an area of intense investigation. Non-invasive methods for examining tissue include palpation, thermography, PET, SPECT, Nuclear imaging, X-ray, MRI, CT, and ultrasound imaging. When the physician suspects that tissue may contain cancerous cells, a biopsy may be done either in an open procedure or in a percutaneous procedure. For an open procedure, a scalpel is used by the surgeon to create a large incision in the tissue in order to provide direct viewing and access to the tissue mass of interest. Removal of the entire mass (excisional biopsy) or a part of the mass (incisional biopsy) is performed. For a percutaneous biopsy, a needle-like instrument is inserted through a very small incision to access the tissue mass of interest and to obtain a tissue sample for later examination and analysis. 
     The advantages of the percutaneous method as compared to the open method are significant: less recovery time for the patient, less pain, less surgical time, lower cost, less risk of injury to adjacent bodily tissues such as nerves, and less disfigurement of the patient&#39;s anatomy. 
     Generally there are two ways to percutaneously obtain a portion of tissue from within the body: aspiration and core sampling. Aspiration of the tissue through a fine needle requires the tissue to be fragmented into pieces small enough to be withdrawn in a fluid medium. This method is less intrusive than other known sampling techniques, but one may only examine cells in the liquid (cytology) and not the cells and the structure (pathology). In core sampling, a core or fragment of tissue is obtained for histologic examination and/or genetic tests, which may be done via a frozen or paraffin section. The type of biopsy used depends mainly on various factors present in the patient, and no single procedure is ideal for all cases. However, core biopsies seem to be more widely used by physicians. 
     The following patent documents are incorporated herein by reference for the purpose of illustrating biopsy devices and methods: U.S. Pat. No. 5,526,822 issued Jun. 18, 1996; U.S. Pat. No. 5,895,401 issued Apr. 20, 1999; U.S. Pat. No. 6,086,544 issued Jul. 11, 2000; U.S. Pat. No. 6,620,111 issued Sep. 16, 2003; U.S. Pat. No. 6,626,849 issued Sep. 30, 2003; U.S. Pat. No. 6,638,235 issued Oct. 28, 2003; US Patent Application 2003/0109803 published Jun. 12, 2003; US Patent Application 2003/0199753 published Oct. 23, 2003; US Patent Application 2003/0199754 published Oct. 23, 2003; US Patent Application 2003/0199785 published Oct. 23, 2003; and U.S. Ser. No. 08/825,899 filed on Apr. 2, 1997. 
     It is known in the art to use a double lumen biopsy needle incorporating vacuum suction to obtain a tissue sample. With devices of this type, the needle is inserted into a small incision in a patient and is advanced through tissue until the needle is adjacent the tissue of interest. At that point, a vacuum source may be activated, providing suction inside one of the two lumens. The suction is communicated to the second lumen via a passage between the two lumens. The second lumen may contain an aperture through which suspicious tissue may be drawn when the vacuum source is activated. Once tissue is drawn into the aperture, the surgeon may advance a cutter through the second lumen in order to excise a sample from the tissue of interest. 
     While biopsy needles of the type described above are useful in obtaining tissue samples, the processes known in the art for manufacturing these needles are often expensive and labor-intensive due to the number of components and steps involved. For instance, certain biopsy needles provide a double lumen structure formed of two separate rigid structures, thus requiring a reliable method of attaching the two structures, such as a weld or adhesive, along the entire length of the lumens. Similarly, many biopsy needles include a sharpened feature on the leading end of the needle that cuts through tissue as the needle is advanced into the body. These sharpened tips often have small components and/or features that require significant time and expense to make and attach to the needle. Further, biopsy needles often include a mounting component that allows the needle to be attached to a handle or other platform. Often, these mounting components are manufactured separately from the body of the needle, and must be joined together after formation, such as by gluing, a process that is heavily reliant on the skill and concentration of a human worker. Even if a more reliable method of attaching the mounting component to the needle is used, such as induction heating or heat staking, such methods still involve the added expense necessitated by the extra assembly equipment as well as the steps of manufacturing the mounting component and attaching it to the needle. 
     Accordingly, while double lumen biopsy needles are known in the art, there exists a significant need for a process of manufacturing a biopsy needle that reduces the number of components that must be separately manufactured, as well as the time and labor that must be expended in manufacturing and assembling the components of the biopsy needle, while still maintaining the necessary strength and rigidity for safe and satisfactory performance during surgery. 
     SUMMARY OF THE INVENTION 
     The process of the current invention overcomes the above-noted and other deficiencies of the prior art by providing a process for manufacturing a biopsy needle device that reduces the number of components that must be separately manufactured and assembled, thereby reducing the cost of manufacturing the biopsy needle device while maintaining the necessary biomechanical properties. 
     In one aspect consistent with the present invention, a process of manufacturing a biopsy needle may comprise the steps of forming an aperture for receiving tissue to be sampled in an exterior surface of an elongated tube that has a proximal and distal portion, wherein the elongated tube may be configured to receive a cutter; forming a hole in the exterior surface of the elongated tube; and applying a coating of material over the elongated tube to form a lumen for receiving vacuum on the exterior surface of the elongated tube, wherein the hole in the exterior surface of the elongated tube may be adapted to provide communication between an interior of the elongated tube and an interior of the lumen. This process advantageously allows the vacuum lumen to be formed over the elongated tube without requiring separate manufacturing and assembly steps, thus reducing assembly costs. 
     In another version, the process of manufacturing the biopsy needle device may comprise the steps of forming an aperture for receiving tissue to be sampled in an exterior surface of an elongated tube, wherein the elongated tube may be adapted to receive a cutter and may further comprise a proximal portion and a distal portion; forming a hole in the exterior surface of the elongated tube; and placing the elongated tube in a mold and injecting the mold with a material, wherein the mold may be configured such that the material forms a lumen for receiving vacuum on the exterior surface of the elongated tube, and wherein further the hole in the exterior surface of the elongated tube may be adapted to provide communication between an interior of the elongated tube and the interior of the lumen. This version advantageously provides for the formation of a vacuum lumen on an elongated tube by overmolding a coating of material onto the elongated tube, avoiding the need to separately manufacture the vacuum lumen and then attach it to the elongated tube. Further, this process may provide for a stronger attachment between the vacuum lumen and the elongated tube than some previously known methods of attachment of the two components. 
     In another aspect, the process of manufacturing a biopsy needle device may comprise the steps of placing a cutter tube, which may comprise a port adapted to receive a tissue sample and may further comprise a cutter lumen adapted to receive a cutter, in a mold; injecting a material in a liquid state into the mold; cooling the material in order to convert it to a solid state; wherein the mold may be configured to cause the material to form a lumen for receiving vacuum on an exterior surface of the cutter tube, and wherein further the vacuum lumen is in communication with the cutter lumen. 
     The present invention also extends to a biopsy instrument manufactured according to a process that may comprise the steps of forming an aperture for receiving tissue to be sampled in an exterior surface of an elongated tube for receiving a cutter, wherein the elongated tube may have a proximal portion and a distal portion; forming a hole in the exterior surface of the elongated tube; and applying a coating of material over the elongated tube to form a lumen for receiving vacuum on the exterior surface of the elongated tube, and wherein the hole in the exterior surface of the elongated tube may be adapted to provide communication between an interior of the elongated tube and an interior of the lumen. 
     These and other objects and advantages of the process of the present invention shall be made apparent from the accompanying drawings and the description thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features and steps of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to organization and methods of operation, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is an isometric view of a hand-held vacuum-assisted biopsy device including a needle assembly manufactured according to one version of the process. 
         FIG. 2  is a side view of a needle assembly manufactured according to one version of the process. 
         FIG. 3  is a top view of a needle assembly manufactured according to one version of the process. 
         FIG. 4  is a side view of a distal tissue-piercing tip manufactured according to one version of the process. 
         FIG. 5  is an isometric view of a distal tissue-piercing tip manufactured according to one version of the process. 
         FIG. 6  is a section view of a cutter lumen and cutter stop manufactured according to one version of the process. 
         FIG. 7  is a section view of a cutter stop manufactured according to one version of the process. 
         FIG. 8  is a partial view of a cutter lumen and axial slide according to one version of the process. 
         FIG. 9  is an isometric view of a right half of a needle assembly mold with slides in place for use in injection molding according to one version of the process. 
         FIG. 10  is a partial frontal cross-sectional view of a needle assembly manufactured according to one version of the process. 
         FIG. 11  is a partial sagittal cross-sectional view of a needle assembly manufactured according to one version of the process. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a hand-held vacuum-assisted biopsy device  10  comprising a handle  20  detachably connected to a needle assembly  30  having a proximal portion  32  and a distal portion  34  manufactured according to a version of the process of the current invention. Together, they constitute a lightweight, ergonomically-shaped, hand-manipulated biopsy device  10 . In one aspect, needle assembly  30  may be part of a disposable probe that may mount on handle  20 . In one aspect, hand-held biopsy device  10  may be used in conjunction with an ultrasound to guide needle assembly  30 . Since handle  20  may be manipulated by the operator&#39;s hand, the operator may steer needle assembly  30  with great freedom towards the tissue mass of interest. The surgeon has tactile feedback while doing so and may therefore ascertain to a significant degree the density and hardness of the tissue being encountered. In addition, handle  20  may be held approximately parallel to the chest wall of a patient for obtaining tissue portions closer to the chest wall than may be obtained when needle assembly  30  is attached to another type of device. Alternatively, needle assembly  30  may be attached to an electromechanical arm, a platform, a table or other suitable support. Such alternative mountings may be used in conjunction with applications in which the needle assembly is guided by stereotactic (x-ray) or MRI modalities. 
     As controls for obtaining a tissue sample, handle  20  may include a forward button  36  which may be used to move a cutter  38  distally through a cutter lumen  40  to sever a sample of suspicious tissue collected in a tissue-receiving port  42 . Handle  20  may further include a reverse button  44  which may be used to move cutter  38  proximally through cutter lumen  40 , thereby moving the tissue sample in port  42  to a tissue collection surface  46 . A vacuum button  48  on handle  20  may be used to open or close a first vacuum line  50  for communicating suction to a vacuum lumen  52  so as to cause tissue to become disposed within port  42  and a second vacuum line  54  for communicating axial suction to cutter  38  to aid in withdrawal of a severed tissue sample. 
     Referring now to  FIGS. 2 and 3 , a needle assembly  30  made by one version of the process of the current invention for use with a biopsy device  10  is illustrated. Cutter lumen  40  may comprise a proximal portion  56  and a distal portion  58 . Cutter lumen  40  forms a smooth, uninterrupted passage for receiving cutter  38  (not shown in  FIGS. 2-3 ) such that it may be advanced through the proximal portion  56  of cutter lumen  40  to the distal portion  58 . Tissue-receiving port  42  may be formed in an exterior surface  60  of cutter lumen  40 . Port  42  may be located on the distal portion  58  of cutter lumen  40 . Cutter lumen  40  may also comprise an open proximal end  62  and an open distal end  64 . 
     Vacuum lumen  52  may comprise a proximal portion  66  and a distal portion  68 . In one version, cutter lumen  40  may be oriented above vacuum lumen  52 . A vacuum source (not pictured) may be attached to vacuum lumen  52 , possibly at proximal portion  66  thereof, via first vacuum line  50 . 
     The needle assembly  30  may also include one or more passages, also called interlumen vacuum holes  70 , between cutter lumen  40  and vacuum lumen  52 . When the vacuum source is activated, thereby providing suction in vacuum lumen  52 , interlumen vacuum holes  70  allow that suction to be communicated into cutter lumen  40 . As best illustrated in  FIGS. 3 and 11 , the interlumen vacuum holes  70  may be located between cutter lumen  40  and vacuum lumen  52  opposite the tissue-receiving port  42 . As illustrated in  FIG. 6 , a cutter stop  72  may also be located in cutter lumen  40  distally of tissue-receiving port  42 . A face  74  of cutter stop  72  may provide a cutting surface for severing a tissue sample. Face  74  of cutter stop  72  may be designed to match the leading profile of cutter  38  ( FIGS. 6 and 7 ). Depending on the means used to advance cutter  38 , cutter stop  72  may also provide tactile feedback to a surgeon once cutter  38  comes into contact with cutter stop  72  after a sample has been severed. However, if, as known in the art, a computer software program is used to control advancement of cutter  38 , the surgeon will not be provided with tactile feedback by contact between cutter  38  and cutter stop  72 . 
     As illustrated in  FIG. 2 , a hub  76  having a proximal portion  78  and a distal portion  80  may be located on proximal portion  32  of needle assembly  30 . Hub  76  assists in mounting needle assembly  30  to handle  20  or other any other suitable support. Hub  76  may detachably mount on handle  20  in order to allow disposable needle assembly  30  to be removed from the multiple-use handle  20  after surgery. Hub  76  may also include a flange  82  on its distal portion  80 . Flange  82  may snap into a rib or similar retaining element (not shown) of handle  20  or another suitable support. Hub  76  may also include a vacuum manifold  84  that provides a connection between the vacuum source and vacuum lumen  52 . Hub  76  may also allow second vacuum line  54  to connect with cutter  38  so that axial suction may be communicated to cutter  38 . 
     In one aspect consistent with the process of the current invention, a distal tissue-piercing tip  86  having a proximal portion  88  and a distal portion  90  may be disposed on distal portion  34  of needle assembly  30 . As best pictured in  FIGS. 4 and 5 , distal portion  90  of distal tissue-piercing tip  86  may include a cutting edge  92  of sufficient sharpness to cut through human tissue and thereby aid in moving needle assembly  30  adjacent to the tissue of interest. The junction of piercing tip  86  and cutter lumen  40  may include a tapered profile  94  therebetween that further assists needle assembly  30  in moving smoothly through a patient&#39;s tissue. 
     Piercing tip  86 , particularly the distal portion  90 , may comprise a substantially flat blade formed of any suitable material. Piercing tip  86  may also include tabs  96 ,  98  ( FIGS. 4 ,  5 ,  11 ) on proximal portion  88  thereof to aid in the attachment of piercing tip  86  to cutter lumen  40 . Tab  96  may be located above tab  98 . In one version, tab  98  extends further toward proximal end  62  of cutter lumen  40  than does tab  96  for reasons addressed below. Piercing tip  86  may also include an opening  100 , to aid in formation of tapered profile  94 , which is also discussed in more detail below. 
     In operation, needle assembly  30  may be inserted into a small incision in the body. When utilized, tissue-piercing tip  86  helps needle assembly  30  penetrate through tissue until distal portion  34  of needle assembly  30  is located adjacent the tissue of interest. Piercing tip  86 , along with tapered profile  94 , may help to minimize tissue drag experienced during insertion and extraction of needle assembly  30 . Once needle assembly  30  is properly positioned relative to the tissue of interest, vacuum suction may be applied to vacuum lumen  52  via first vacuum line  50 . 
     Suction may be communicated from vacuum lumen  52  to cutter lumen  40  via the interlumen vacuum holes  70 . The suction inside cutter lumen  40  actively pulls suspicious tissue into tissue-receiving port  42 . Once the suspicious tissue has been drawn into cutter lumen  40  through port  42 , the surgeon may advance cutter  38  in the distal direction until a sample is severed from the suspicious tissue. Cutter stop  72  may be located in cutter lumen  40  distally of tissue-receiving port  42  to provide a cutting surface to aid cutter  38  in severing a sample of suspicious tissue. Once the sample has been severed, cutter  38  may contact cutter stop  72 . As mentioned above, depending on the means used to advance cutter  38  through cutter lumen  40 , contact between cutter  38  and cutter stop  72  may provide tactile feedback to the surgeon, indicating that a sample has been obtained and that cutter  38  may be withdrawn toward proximal end  62  of cutter lumen  40 . Once cutter  38  contacts cutter stop  72 , needle assembly  30  may be repositioned in the patient&#39;s body (e.g., rotated, longitudinally translated) in order to obtain another sample. 
     As mentioned above, cutter  38  may be attached to second vacuum line  54 , thereby providing cutter  38  with axial suction. After a sample has been obtained, and before a second sample is drawn into port  42 , axial suction, if utilized, may assist cutter  38  in pulling the sample through cutter lumen  40  as cutter  38  is withdrawn. Once cutter  38  has been withdrawn from cutter lumen  40 , the sample may be cleared from cutter  38  onto the tissue collection surface  46  located on handle  20  or platform. At that point, another sample may be obtained by applying vacuum to draw a sample into port  42  and advancing cutter  38  to sever the sample. This procedure may be repeated until the desired number of samples has been acquired. 
     In one aspect consistent with the process of the current invention, cutter lumen  40  may comprise a preformed tube open at each end and cut to the desired length of needle assembly  30 . The preformed tube may be advantageously straight and round for receiving cutter  38 . The material of the preformed tube may be rigid to allow insertion of needle assembly  30  through tissue with minimal deflection. In one version, cutter lumen  40  may be made of metal. More particularly, cutter lumen  40  may be made of stainless steel. Cutter lumen  40  may also be made from other suitable materials, including but not limited to titanium, titanium alloy, aluminum, or aluminum alloy. Alternatively, cutter lumen  40  may be made from nonmetallic materials having structural characteristics sufficient to allow a coating of material to be applied over cutter lumen  40  and having the strength and rigidity characteristics sufficient to withstand the force experienced by cutter lumen  40  when it is pressed through human tissue. 
     Tissue-receiving port  42  and interlumen vacuum holes  70  may be cut into the preformed tube comprising cutter lumen  40 . As shown in  FIG. 3 , the distal and proximal edges of port  42  may be cut on an angle relative to the longitudinal edges of port  42 . The angling of these edges can produce a scissoring effect as needle assembly  30  is pushed through tissue, aiding in positioning the device  10 . In addition, a pair of notches  101 ,  102  ( FIG. 8 ) may be cut into distal end  64  of the preformed tube comprising cutter lumen  40  to provide points of attachment for piercing tip  86 . 
     Piercing tip  86  may be formed of a material providing sufficient strength and rigidity to allow it to move through tissue with minimal deflection. In one version, tip  86 , including the above-described features included thereon, may be stamped from metal sheet stock. More particularly, the metal may be 440A stainless steel. However, other suitable materials may be used, including but not limited to titanium, titanium alloy, aluminum, or aluminum alloy. Non-metallic materials, such as MRI compatible resins, including but not limited to Ultem and Vectra, may be used to form tip  86 . Likewise, tip  86  may also be formed from ceramics or glass. By stamping piercing tip  86  out of metal sheet stock, cutting edge  92  may be sharpened prior to attachment of tip  86  to cutter lumen  40 . Cutting edge  92  may be sharpened after formation of tip  86  by grinding perpendicular to cutting edge  92 , which is sometimes thought to be advantageous in producing a sharp cutting surface. Alternatively, cutting edge  92  may be sharpened by any other suitable method known in the art. 
     Piercing tip  86  may be attached to cutter lumen  40 . In one version, piercing tip  86  may be welded to cutter lumen  40 . More particularly, piercing tip  86  may be laser welded to cutter lumen  40 . In one version, piercing tip  86  may be welded to cutter lumen  40  at two preformed locations. Tabs  96 ,  98  of piercing tip  86  may each be welded inside the notches  101 ,  102  of cutter lumen  40 . Alternatively, piercing tip  86  may be attached to cutter lumen  40  through any suitable method known in the art that provides satisfactory strength of attachment between tip  86  and cutter lumen  40 , including but not limited to adhesive, press-fit, or screws. 
     Other features of needle assembly  30  may be formed by applying a coating of material over cutter lumen  40 . The coating of material may be applied to cutter lumen  40  as a liquid, and then hardened to the necessary rigidity for use in the human body after formation of the desired features thereon. In one version depicted in  FIG. 9 , the coating of material may be applied to cutter lumen  40  by injection molding. In this version, a mold  103  is designed such that the injected material may flow into predetermined cavities and form the desired features over cutter lumen  40 , including but not limited to vacuum lumen  52  and hub  76 . The gates (not pictured) through which the material is injected into the mold may be located along the mold part line, shown as P L  in  FIG. 9 . Further, the gates may be located in the mold  103  underneath cutter lumen  40 . 
     In this version, when the material is injected into the mold  103 , it may form an outer sheath  106  over cutter lumen  40 , as well as tapered profile  94  between piercing tip  86  and cutter lumen  40  ( FIGS. 6 ,  7 ,  10 ,  11 ). To assist in formation of tapered profile  94 , piercing tip  86  may include opening  100  ( FIG. 4 ) through which the injected material may flow. Flow of injected material through opening  100  from each side of tip  86  may strengthen attachment of the injected material to piercing tip  86 . 
     The mold  103  may also be shaped so that the applied material forms hub  76 , flange  82 , and vacuum manifold  84  over proximal portion  56  of cutter lumen  40 . The mold  103  may also be designed so that hub  76  extends past proximal end  62  of cutter lumen  40  in order to facilitate the mounting of needle assembly  30  to handle  20  or another suitable support. Alternatively, hub  76 , including flange  82  and vacuum manifold  84  may be formed separately from the remainder of needle assembly  30  and be attached by gluing, press-fitting or any other suitable method known in the art. 
     Referring to  FIG. 9 , prior to application of the coating of material, a slide  108  may be placed along exterior surface  60  of cutter lumen  40 , substantially parallel to the longitudinal axis thereof. More particularly, slide  108  may be placed on the underside of exterior surface  60 . The material then coats cutter lumen  40  and slide  108 , forming vacuum lumen  52  substantially parallel to the longitudinal axis of cutter lumen  40 . Slide  108  also serves to prevent the applied material from blocking interlumen vacuum holes  70 . The mold  103  may also be designed so that slide  108  may be placed in alternate locations in order to orient vacuum lumen  52  above or to either side of cutter lumen  40 , so long as at least one interlumen vacuum hole  70  is present between vacuum lumen  52  and cutter lumen  40  to allow suction to be communicated therebetween. 
     While use of slide  108  is one process for forming vacuum lumen  52  in the coating of material applied over cutter lumen  40 , it is recognized that other methods of forming vacuum lumen  52  in the coating of material are also possible. For example, vacuum lumen  52  could be drilled out of the coating of material after the material reaches sufficient hardness. 
     As shown in  FIG. 10 , in one version consistent with the invention, the coating of material provides the combined cutter lumen  40  and vacuum lumen  52  with an egg-shaped frontal cross-section  110 . During surgery, cross-section  110  promotes efficient motion of the needle assembly  30  through tissue. However, it is recognized that the application of a coating of material to cutter lumen  40  may provide needle assembly  30  with cross-sections of various shapes that are consistent with the process of the current invention. Further, as illustrated in  FIGS. 9 and 10 , slide  108  may comprise a scoop-shaped cross-section  111  that provides vacuum lumen  52  with a generally scoop-shaped frontal cross-section  112 . While this is helpful in providing the combined cutter lumen  40  and vacuum lumen  52  with the egg-shaped frontal cross-section  110  described above, vacuum lumen  52  and slide  108  could comprise various frontal cross-sections that are consistent with the process of the current invention. For instance, slide  108  could have a circular frontal cross-section, thus providing vacuum lumen  52  with a circular frontal cross-section. 
     As shown in  FIGS. 4 and 5 , tab  98  on piercing tip  86  may be elongated and slope downward in the proximal direction. In addition to serving as a point of attachment for welding piercing tip  86  to cutter lumen  40 , tab  98  may also align and help hold slide  108  in place during molding. 
     Prior to application of the material to cutter lumen  40 , a slide  112  ( FIG. 9 ) may be inserted into tissue-receiving port  42 . Slide  112  prevents any of the applied material from entering port  42 . 
     Referring now to  FIGS. 8 and 9 , an axial slide  114  having a proximal end  116  and a distal end  118  may be inserted into open proximal end  62  of cutter lumen  40  prior to application of the coating of material. Axial slide  114  prevents the applied material from entering proximal end  62  of cutter lumen  40 . Further, axial slide  114  may be of a predetermined length such that distal end  118  extends into cutter lumen  40  distally of tissue-receiving port  42  but does not reach open distal end  64  of cutter lumen  40 . Distal end  118  of slide  114  may further comprise an indentation  120 . Piercing tip  86  may be attached to distal end  64  of cutter lumen  40  in a manner that does not prevent material from flowing into open distal end  64  during application of the material over cutter lumen  40 . Accordingly, during the application process, material flows into open distal end  64  of cutter lumen  40  and into indentation  120  in axial slide  114 , thereby forming cutter stop  72  in cutter lumen  40  distally of tissue-receiving port  42 . 
     Additionally, in one version of the present invention, one or more slides may be placed against exterior surface  60  of cutter lumen  40  in order to hold cutter lumen  40  in position while the material is applied over cutter lumen  40  and prevent deformation due to the pressure of the applied material against exterior surface  60 . As a result, outer sheath  106  may include windows  122  ( FIG. 3 ) through which cutter lumen  40  is exposed. 
     The injected material may be selected from materials including, but not limited to, plastics, thermoplastics, thermoresins, and polymers. For instance, the molded features may be formed of a liquid crystal polymer or a glass reinforced polymer. One suitable material is a glass reinforced liquid crystal polymer such as VECTRA A130 available from Ticona Corp. In one version, the injected material may have a melt flow index of at least about 10 grams/minute, more particularly at least about 15 grams/minute. Without being limited by theory, such a mold flow index is thought to be beneficial for molding relatively long, thin-walled cross-sections. 
     While various versions of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such alternatives are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the present invention. Additionally, each component or element may be described in terms of a means for performing the component&#39;s function. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.