Abstract:
The present invention discloses needles configured to prevent or reduce contact of tissue or other material with the heel of the needle to prevent coring of the tissue or other material by the heel of the needle. Also provided are needles having no heels or blunted heels. The present invention also provides methods of manufacturing needles having obstructed or blunted heels.

Description:
FIELD OF THE INVENTION 
   The present invention relates to needles that minimize or prevent damage to the site in which the needles are inserted. 
   BACKGROUND OF THE INVENTION 
   Needles have a wide variety of applications in the medical field. For instance, needles are used to delivery therapeutic agents, collect bodily fluids, and fill drug delivery ports. In many such applications, there is a desire to avoid or reduce damage to the site in which the needle is inserted. For example, drug delivery ports such as intravascular drug access devices often include a chamber for holding a therapeutic agent and a pierceable rubber septum for receipt of a needle to either fill or empty the chamber. Repeated piercing of the septum with the needle can damage the septum leading to infusion of the septum fragments into the patient&#39;s vascular system or into any catheter or other device having access to the port, thereby occluding the port. 
   With respect to delivering a therapeutic agent to a target site in the body, particularly directly delivering a therapeutic agent to a target site, current injection needles have beveled open ends with Lancet point tips. Such open-ended needles have the potential to core tissue as the needles penetrate the tissue. In the case of directly delivering a therapeutic agent to a myocardial wall of the heart, since most myocardial direct injection procedures involve injecting a therapeutic agent into the left ventricle walls, the risk of tissue embolism into the left ventricular cavity exists. 
   Needle tips, such as the “pencil-point” needle and the “Huber” needle have been developed that attempt to reduce coring by the needle. A Huber needle has a distal portion with a lateral bend and a laterally facing opening. The needle terminates in a sharpened closed tip. A pencil-point needle has a lateral opening and a closed tip at the distal end. Because there are no distal openings in these types of needles, any therapeutic agent that passes through the lumens of these needles exits these laterally facing openings, which will direct the therapeutic agent in a radial direction. Such radial delivery may result in the therapeutic agent being ejected or squeezed back through its point of entry in the target site. This problem is exacerbated in situations where the therapeutic agent is injected into an actively contracting tissue such as the myocardium of the heart. In such a case, the therapeutic agent may be ejected or squeezed out through its point of entry by the repeated expansion and contraction of the heart muscle. This unintended and unwanted leakage can result in an unascertainable dosage of the therapeutic being ultimately received by the target site and arbitrary and unwanted interaction between leaked therapeutic agent and neighboring tissue and muscle. 
   Accordingly, there is a need for a needle that will prevent or minimize damage to the site in which the needle is inserted and that will direct the delivery of a therapeutic agent, or any infusion material, in a distal direction out of the needle. 
   SUMMARY OF THE INVENTION 
   In certain embodiments, the present invention provides a needle comprising a shaft having a heel and an infusion lumen extending therethrough and a buffer disposed within the infusion lumen of the shaft. The buffer has a blunt distal end obstructing the heel of the shaft. 
   In certain embodiments, the present invention provides a needle for delivering an infusion material to a target site that comprises a shaft having a longitudinal axis, an infusion lumen extending therethrough, and a distal end terminating in a closed tip. The distal end of the shaft defines at least one lateral port that is offset from the longitudinal axis of the shaft. The at least one lateral port is angled in a direction to direct flow of the infusion material in a distal direction. 
   In certain embodiments, the present invention provides a needle comprising a shaft having a distal surface, an inlet port and an outlet port, and an infusion lumen extending between the inlet port and the outlet port. The needle further comprises an elongated penetration member slidably disposed within the infusion lumen of the shaft. The penetration member comprises a stem and a head portion, which has a closed distal tip and a proximal surface. The penetration member is capable of having a retracted configuration and an extended configuration. In a retracted configuration, the proximal surface of the head portion abuts against the distal surface of the shaft to close the outlet port and in an extended configuration, the head portion distally extends away from the distal surface of the shaft to open the outlet port. 
   In certain embodiments, the present invention provides a needle comprising a cannulated shaft having a longitudinal axis and a distal end. The distal end has a trailing portion and a leading portion terminating in a pointed tip. The leading portion, according to these embodiments of the present invention, is angled towards the trailing portion. 
   In certain embodiments, the present invention provides a needle comprising a shaft having a distal end and opposing first and second inner walls that mutually define an infusion lumen. The distal end, according to these embodiments of the present invention, has a blunted heel. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only and wherein: 
       FIG. 1  is a perspective view of an embodiment of a needle according to an aspect of the present invention. 
       FIG. 2  is a cross-sectional view of an embodiment of a needle according to an aspect of the present invention. 
       FIG. 3  is a cross-sectional view of an alternative embodiment of a needle according to an aspect of the present invention. 
       FIG. 4  is a cross-sectional view of an alternative embodiment of a needle according to an aspect of the present invention. 
       FIG. 5  is a perspective view of an alternative embodiment of a needle according to an aspect of the present invention. 
       FIG. 6  is an end view of the needle depicted in  FIG. 5 . 
       FIG. 7  is a cross-sectional view of an alternative embodiment of a needle with a buffer in a retracted configuration according to an aspect of the present invention. 
       FIG. 8  is similar to  FIG. 7  but depicting the buffer in an extended configuration. 
       FIG. 9  is a perspective view of an embodiment of a needle according to another aspect of the present invention. 
       FIG. 10A  depicts a stage of an embodiment of manufacturing the needle of  FIG. 9 . 
       FIG. 10B  depicts a stage of manufacturing the needle of  FIG. 9 . 
       FIG. 10C  depicts a stage of manufacturing the needle of  FIG. 9 . 
       FIG. 10D  depicts a stage of an embodiment of an alternative embodiment of manufacturing the needle of  FIG. 9 . 
       FIG. 11  is a cross-sectional view of a needle according to an embodiment of another aspect of the present invention. 
       FIG. 12  is a cross-sectional view of a needle according to an alternative embodiment of another aspect of the present invention. 
       FIG. 13  is a perspective view of a needle comprising a penetration member in an extended configuration according to an aspect of the present invention. 
       FIG. 14  is similar to  FIG. 13  but depicting the penetration member in a retracted configuration. 
       FIG. 15  is a cross-sectional view of a needle comprising an alternative embodiment of a penetration member in a retracted configuration according to an aspect of the present invention. 
       FIG. 16  is similar to  FIG. 15  but depicting the penetration member in an extended configuration. 
       FIG. 17  is a side view of an embodiment of a needle according to another aspect of the present invention. 
       FIG. 18  is an end view of the needle depicted in  FIG. 17 . 
       FIGS. 19A-19D  depict respective stages of manufacture of the needle depicted in  FIG. 17 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIG. 1 , one embodiment of the present invention provides a needle  10  for delivering an infusion material to a target site that comprises a shaft  20  having a proximal end  30  defining an inlet port  40  and a distal end  50  (referred to herein as the bevel of shaft  20 ) defining an outlet port  60 . Bevel  50  has a leading portion  50   a  and a trailing portion  50   b  that includes a trailing surface  50   b ′. Referring to  FIG. 2 , which is a cross-sectional view of needle  10  of  FIG. 1 , shaft  20  also has an annular inner wall  96  that defines an infusion lumen  70  extending between inlet port  40  and outlet port  60 . Bevel  50  of shaft  20  has a heel  80 , which is the edge of bevel  50  where trailing surface  50   b ′ and inner wall  96  meet. According to the present invention, a buffer  90  with a blunt distal end  95  obstructing heel  80  is disposed within infusion lumen  70  of shaft  20 . Because blunt distal end  95  obstructs heel  80 , it reduces or prevents contact of a target site with heel  80  since as needle  10  penetrates into the target site, the target site is exposed to blunt distal end  95  of buffer  90  instead of heel  80 . Although blunt distal end  95  obstructs heel  80 , it does not completely occlude outlet port  60  thereby allowing any infusion material that passes through needle  10  to be directed out of outlet port  60  in the distal direction. 
   Blunt distal end  95  of buffer  90  may have any configuration to effectively prevent or reduce coring of the target site by heel  80 . For example, blunt distal end  95  may be completely rounded as illustrated in  FIG. 3  or only partially rounded as illustrated in  FIGS. 4 ,  7  and  8 . Although preferably blunt distal end  95  extends slightly beyond infusion lumen  70  as illustrated in  FIGS. 2 and 3 , blunt distal end  95  may be located completely within infusion lumen  70  aligned with surface  50   b ′ of trailing portion  50   b  as illustrated in  FIG. 4 . Furthermore, buffer  90 , in its entirety, may have any configuration so long as distal end  95  remains blunt to effectively prevent or reduce coring of the target site by heel  80 . For example, referring to  FIG. 3 , in one embodiment, buffer  90  has an elongated configuration such that buffer  90  spans the entire length of infusion lumen  70  between inlet port  40  and outlet port  60 . Referring to  FIG. 2 , in another embodiment, buffer  90  has a spherical, pellet-like configuration such that buffer  90  only covers heel  80 . Of course, buffer  90  may also have any intermediate size therebetween. For example, referring to  FIG. 4 , in another embodiment, buffer  90  does not span the entire length of infusion lumen  70  but contacts more than just heel  80  of bevel  50 . Referring to  FIG. 5 , in another embodiment, buffer  90  is a webbing or plug that can be inserted into infusion lumen  70  and that has a crescent-shaped cross-sectional configuration (depicted in  FIG. 6 ) such that buffer  90  covers heel  80  and the adjacent area of bevel  50 . 
   Buffer  90  can be fixedly attached to or in slidable engagement with inner wall  96  of shaft  20 . With respect to the latter embodiment, referring to  FIGS. 7 and 8 , buffer  90  may be slidably disposed in infusion lumen  70  to provide axial movement of buffer  90  within infusion lumen  70 . For example, referring to  FIG. 7 , to initially penetrate the surface of the target site, buffer  90  can be retracted within infusion lumen  70  so that heel  80  is unobstructed during the initial entry process. Referring to  FIG. 8 , once the surface of the target site has been broken, buffer  90  can be axially extended to abut heel  80  so that heel  80  is covered during the remainder of the penetration process. 
   Buffer  90  may be fabricated of any biocompatible material such as a polymeric, woven, or metallic material (including stainless steel, nitinol, or other shape-memory materials). In order to further protect tissue, buffer  90  may be fabricated of an elastomeric material that provides a cushioning effect to the target site that contacts buffer  90 . Buffer  90  may be separately molded into infusion lumen  70  against heel  80  or may be extruded into shaft  20  or co-extruded with shaft  20  during the fabrication of needle  10 . 
   Referring to  FIG. 9 , another embodiment of the present invention provides a needle  500  comprising a shaft  510  having a proximal end  520  defining an inlet port  530  and a bevel  540  defining an outlet port  550 . Bevel  540  has a leading portion  540   a  and a trailing portion  540   b  that includes a trailing surface  540   b ′. Referring to  FIG. 10C , which is a cross-sectional view of needle  500  of  FIG. 9 , shaft  510  also has an annular inner wall  515  defining an infusion lumen  517  extending between inlet port  530  and outlet port  550 . According to this embodiment of the present invention, bevel  540  of shaft  510  has a blunted heel  560  to reduce or eliminate any coring of a target site. 
   Referring to  FIGS. 10A-10D , in one embodiment, blunted heel  560  is formed by providing a pre-form needle  600  having a heel  610  at distal end  620  (illustrated in  FIG. 10A ) and machining distal end  620  to remove a portion  615  of heel  610  (illustrated in  FIG. 10B ) to form needle  500  of the present invention having a blunted heel  560  (illustrated in  FIG. 10C ). Distal end  620  of pre-form needle  600  may be machined by any means known in the art to remove portion  615  of distal end  620 , such as by turning, drilling, milling, grinding, electrical discharge machining, electrochemical machining, abrasive flow machining, ultrasonic machining or other electrical, chemical or physical machining processes known to one of skill in the art. Referring to  FIG. 10A , in one exemplary machining process, mill  630  is placed against distal end  620  in a position substantially perpendicular to longitudinal axis X of pre-form needle  600 . Mill  630  is then rotated while moderate force is applied to heel  610  to mill away portion  615  of heel  560  to form needle  500  having blunted heel  560 . Mill  630  may be rotated manually or such rotation may be automated through the use of a vise or other clamping device that receives mill  630 . 
   Referring to  FIG. 10D , in another embodiment, blunted heel  560  is formed by providing a pre-form needle  600  having a heel  610  at distal end  620  and having an annular inner wall defining an infusion lumen. Specifically, annular inner wall has a first side  650  and an opposing second side  660  that mutually define an infusion lumen  670 . According to this method, a pick  640  is placed against distal end  620  at an angle to longitudinal axis X of pre-form needle  600 . Pick  640  is rolled against distal end  620  while moderate pressure is applied to heel  610  to fold portion  615  of distal end  620  inwards into infusion lumen  670  towards first side  650  to form needle  500  of the present invention having blunted heel  560 . As will be appreciated by one skilled in the art, other instruments may be used to fold portion  615  inwards into infusion lumen  670  of pre-form needle  600  to form needle  500  having blunted heel  560 . 
   Referring to  FIG. 11 , another embodiment of the present invention provides a needle  200  for delivering an infusion material to a target site that comprises a shaft  210  having a longitudinal axis X, an infusion lumen  215  extending therethrough, and a distal end  230  terminating in a closed tip  240 . According to this embodiment of the present invention, distal end  230  defines at least one lateral port  220  that is offset from longitudinal axis X of shaft  210  and that is angled in a direction to direct flow of infusion material in a distal direction. Because distal end  230  terminates in a closed tip  240 , there is no opening through which tissue or any other material can enter, thereby eliminating any potential coring of the target site. However, needle  200  still provides for distal delivery of the infusion material, since lateral port  220  is angled to direct flow of the infusion material in a distal direction. Lateral port  220  is angled with respect to longitudinal axis X of shaft  210 , and preferably the angle is selected such that the direction of flow A through lateral port  220  is angled at an angle θ less than 90 degrees with respect to longitudinal axis X. Also preferably, the at least one lateral port  220  comprises a plurality of lateral ports  220  to provide more flow and create less infusion pressure through needle  200 . More preferably, each of the plurality of lateral ports  220  are staggered such that each port  220  is located on a different plane of shaft  210  to provide distal end  230  with more column strength. Referring to  FIG. 12 , in a preferred embodiment, distal end  230  is swaged such that distal end defines a pair of ridges  250 , which block any backward leakage of infusion material from the target site once the infusion material has been delivered to the target site. 
   Referring to  FIGS. 13 and 14 , another embodiment of the present invention provides a needle  300  comprising a shaft  310  having a proximal end  320  defining an inlet port  330 , a distal end  340  defining an outlet port  350 , and an infusion lumen  411  extending between inlet port  330  and outlet port  350 . Specifically, distal end  340  has an annular distal surface  325  that defines outlet port  350 . According to this embodiment of the present invention, needle  300  further comprises a penetration member  360  having an elongated stem  412  and a terminal head  390 . Head  390  has a proximal surface  380  and a pointed closed distal tip  370 . Penetration member  360  is capable of having an extended configuration, as illustrated in  FIG. 13  and a retracted configuration, as illustrated in  FIG. 14 . Referring to  FIG. 14 , in a retracted configuration, proximal surface  380  of head  390  abuts against distal surface  325  of shaft  310  to close outlet port  350 . Referring to  FIG. 13 , in an extended configuration, head  390  distally extends away from distal surface  325  to open outlet port  350 . Referring to  FIGS. 15 and 16 , proximal surface  380  of head  390  may define a swaged end  422  that is received by outlet port  350  in a retracted configuration of penetration member  360 . In use, needle  300  penetrates into the target site while penetration member  360  is in a retracted configuration. Because outlet port  350  is closed in a retracted configuration of penetration member  360  (and distal tip  370  is closed), needle  300  does not core or damage the target site into which needle  300  is inserted. After penetration by needle  300  is complete, needle  300  remains stationary and penetration member  360  assumes an extended configuration to open outlet port  350 . Once outlet port  350  is open, infusion material can pass through infusion lumen  411  to the target site. 
   Referring to  FIGS. 17 and 18 , in another embodiment, the present invention provides a needle  400  comprising a cannulated shaft  410  having a distal end  420 . Distal end  420  has a trailing portion  440  and a leading portion  430  that terminates in a pointed tip  450 . According to this embodiment of the present invention, leading portion  430  is angled towards trailing portion  440 . Such a configuration of needle  400  eliminates contact between the target site and heel  460  since leading portion  430  essentially masks or blocks heel  460  as needle  400  is inserted into the target site, thereby preventing any coring of the target site by heel  460 . Referring to  FIGS. 19A-D , needle  400  may be manufactured by providing a workpiece  480  that is fabricated of a malleable or deformable material, and machining the distal end  420  of workpiece  480  to create a trailing portion  440  and a leading portion  430 , as illustrated in  FIG. 19B . Any machining process known to one of skill in the art can be used to remove a portion of distal end  420  such as turning, drilling, milling, grinding, electrical discharge machining, electrochemical machining, abrasive flow machining, ultrasonic machining or other electrical, chemical or physical machining processes known to one of skill in the art. Preferably distal end  420  is ground or milled to create trailing portion  440  and leading portion  430 . Referring to  FIG. 19C , after trailing portion  440  and leading portion  430  are created in workpiece  480 , leading portion  430  is pushed towards trailing portion  440 . Referring to  FIG. 19D , end  470  of leading portion  430  is then sharpened to a pointed tip  450  to form needle  400 . End  470  can be sharpened by any means known in the art, such as by grinding or milling. 
   The present invention also contemplates delivery devices, such as syringes, or catheters, which have attached to the distal portions thereof, a needle according to any embodiment of the present invention to deliver infusion material to a target site. Such needles can then be used to deliver any type of infusion material, such as therapeutic agents, fluids such as saline and water, or diagnostic agents such as contrasting or radio-imaging agents to a target site. The target site can be, for example, an area of the body or any type of receptacle that is configured to receive the infusion material, such as a drug delivery port. 
   The areas of the body into which needles of the present invention can be inserted include any body lumina or organ such as the coronary vasculature, esophagus, trachea, colon, biliary tract, urinary tract, prostate, brain, lung, liver, heart, skeletal muscle, kidney, bladder, intestines, stomach, pancreas, ovary, cartilage, eye, bone, spinal column and the like. Although needles according to the present invention are not in any way limited to a specific application, they are particularly useful for reducing or preventing coring or other damage to tissue. For example, needles of the present invention are useful for inserting into the myocardial wall of the heart, which is accessed from a blood vessel or from the blood stream and that when accessed by needles known in the art, could result is a tissue core entering the blood stream. The needles of the present invention can also be used to deliver anesthesia, such as an epidural or spinal anesthesia, to the spinal column or to deliver any other drug intrathecally. Once again, because of the configuration of the needles of the present invention, excessive damage to the affected area of the spinal column may be minimized or eliminated. 
   Needles according to the present invention can also be used to collect a fluid sample from a fluid containment site of a body. In such an application, the needle is attached to the distal portion of a delivery device such as a syringe, and the needle is inserted into the fluid containment site of the body. A vacuum is created in the delivery device to collect the fluid sample from the fluid containment site. The fluid containment site can be any cavity, sac, or region in general of a body that stores or contains a fluid. Such fluids include, for example, blood, amniotic fluid, serous fluid, and cerebrospinal fluid. Accordingly, non-limiting examples of fluid containment sites include arteries and veins; the amniotic sac; serous cavities such as the peritoneal cavity, the pleural cavity, and the pericardial cavity; and the subarachnoid space. 
   A needle according to any embodiment of the present invention can also be used to access a drug delivery port, such as an intravascular drug access device (IVAD). Such drug delivery ports are used for the delivery of therapeutic agents and are typically implanted in a subcutaneous pocket, such as the anterior upper chest wall below the clavicle. As mentioned previously, the drug delivery ports usually include a chamber for the therapeutic agent and a pierceable septum for receipt of a needle to either fill or empty the chamber. The needles of the present invention can be used to introduce therapeutic agents into these drug delivery ports and because of the particular configuration of the needles of the present invention, damage to the septum is minimized even after repeated piercing of the septum. Of course, it will be understood to one of skill in the art that the needle can also be used to remove a therapeutic agent from the drug delivery port or to flush the drug delivery port with a saline solution, for example. 
   It should be emphasized that the above mentioned methods of using needles of the present invention are merely illustrative and such needles can be used for any other appropriate purpose or application. 
   The foregoing description has been set forth merely to illustrate the invention and is not intended as being limiting. Each of the disclosed aspects and embodiments of the present invention may be considered individually or in combination with other aspects, embodiments, and variations of the invention. In addition, unless otherwise specified, none of the steps of the methods of the present invention are confined to any particular order of performance. Modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art and such modifications are within the scope of the present invention. Furthermore, all references cited herein are incorporated by reference in their entirety.