Abstract:
An apparatus and method for guiding a needle in conjunction with a biopsy using a medical imaging device, where an open-ended needle guide with an adjustable slidable multi-gauge needle stop is used to guide a needle during insertion and during a tilting of the needle with respect to the medical imaging device.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   The present application is a continuation of application Ser. No. 09/682,367 entitled “Method and apparatus for guiding needles”, filed by the same inventor on Aug. 24, 2001, and now U.S. Pat. No. 6,612,990, and which application itself was a continuation-in-part application of an application entitled “Needle guide for attachment to ultrasound transducer probe” by the same inventor, the application having Ser. No. 09/526,048 which was filed on Mar. 15, 2000, and issued as U.S. Pat. No. 6,296,614 on Oct. 2, 2001, which itself was a continuation-in-part of application 29/103,098, also entitled “Needle guide for attachment to ultrasound transducer probe” filed on Apr. 8, 1999, which issued as U.S. Pat. No. Des. 424,693 on May 9, 2000. The above-referenced application, Patent and U.S. Design Patent are incorporated herein in their entirety by these references. 

   BACKGROUND OF INVENTION 
   In recent years, handheld medical imaging transceivers, such as ultrasound and gamma ray transceivers, have been used extensively for various medical imaging situations. In certain procedures, such as biopsies, it may be desired to tilt a needle with respect to a needle guide or vice versa. 
   In the past, the physician or medical professional may be required to detach a biopsy needle from a needle guide prior to changing the angle of the needle with respect to the needle guide and transceiver. Other prior art needle guides have included a pair of spaced-apart fixed parallel plates. The medical professional could place the needle between the parallel plates, and it would be free in a plane parallel with the plates, but restricted from large movements outside that plane. 
   Other prior art needle guides have been used which include a resilient tube coupled to a transducer where the tube has a longitudinal slit through which the needle can be pulled when relative tilting is required. 
   While these needle guides have been used extensively in the past, they do have some drawbacks. First of all, any model of fixed parallel plate needle guide is limited in the size of needle that can be guided therein. If the needle is too big, it will not fit between the fixed parallel plates. If the plates are too far apart, there is less support being provided in the desired direction. Also, these parallel plate needle guides only provide support in one direction. They provide no support or resistance from motion within the plane of the parallel gap between the fixed plates. This increases the attention required by the medical professional. 
   Secondly, the resilient slit tube type of needle guide does provide some resistance to motion in the desired plane of motion, but it is limited to only the first portion of that movement or motion. Once the needle is tilted out of the tube, there is no support or resistance to motion in any direction. Additionally, these types of needle guides will work only with specific gauges of needles. They will not work well when a narrow gauge needle is used in a needle guide primarily designed for a larger needle. The narrower needle may fall through the slit. Conversely, a larger needle may not fit in the tube, or it may be difficult to pull through the slit. Consequently, numerous sized slit tube needle guides would be needed to fulfill the needs of a medical professional who uses needles of varying sizes. Additionally, these slit tube type of needle guides may be viewed as unstable in the direction of relative motion. For example, the force required to be applied to the needle to move the needle in the tilted direction decreases as the amount of tilting occurs. To assure that excess tilting does not occur, the medical professional needs to give more attention to the force being applied when the required force decreases with angular displacement. 
   Consequently, there exists a need for improved methods and apparatus for guiding needles in an efficient manner. 
   SUMMARY OF INVENTION 
   It is an object of the present invention to provide an apparatus and method for guiding a tiltable needle in an efficient manner. 
   It is a feature of the present invention to utilize a multi-gauge adjustable needle guide. 
   It is another feature of the present invention to include a slidable needle stop. 
   It is another feature of the present invention to include a slide-ably adjustable needle guide stop with a bias force for closing the needle guide. 
   It is another feature of the present invention to include needle stops having contours for engaging needles. 
   It is an advantage of the present invention to achieve improved efficiency in guiding needles. 
   The present invention is an apparatus and method for guiding needles designed to satisfy the aforementioned needs, provide the previously stated objects, include the above-listed features, and achieve the already articulated advantages. The present invention is carried out in a “physician burden-less” manner in a sense that the burden on a physician or other medical professional in guiding needles during the process of tilting has been greatly reduced. 
   Accordingly, the present invention is an apparatus and method including a slidable needle stop in a multi-gauge adjustable needle guide. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     The invention may be more fully understood by reading the following description of the preferred embodiments of the invention, in conjunction with the appended drawings wherein: 
       FIG. 1  is a partially exploded perspective view of the apparatus of the present invention. 
       FIG. 2  is an enlarged partially cut-away side view of the needle guide of  FIG. 1 , where the cut-away portion exposes a plurality of detent mechanisms. 
       FIG. 3  is a bottom view of the needle guide of  FIGS. 1 and 2 . 
   

   DETAILED DESCRIPTION 
   Now referring to the drawings wherein like numerals refer to like matter throughout, and more specifically referring to  FIG. 1 , there is shown a needle guide assembly  100 , of the present invention which includes a needle guide  102  with a needle  101  disposed therein. Needle guide  102  is coupled to medical imaging device  103 , which could be an ultrasound transducer, gamma ray transceiver or other imaging device, via a medical imaging device retaining strap  104 , which could be an elastic strap, such as rubber or a less elastic strap, such as fabric or leather. Cables, wires, rope, brackets, clamps or any other suitable substitute could be used for a medical imaging device retaining strap  104 . Needle guide  102  is preferably a plastic material, such as ABS or equivalent; however, other materials, such as aluminum, surgical steel, and any other suitable material could be substituted. 
   The medical imaging device  103  has a transmitting end  105 , which may be a planar face with a vertical axis  107  extending orthogonally therefrom. 
   The term “vertical axis  107 ” is used herein to convey that the axis is orthogonal to the transmitting surface end  105 . Depending on the orientation of the medical imaging device  103 , the vertical axis  107  may be pointed in any direction with respect to the patient or an earth reference. In normal operation, the medical imaging device  103  is often held, at least at first, with the transmitting end  105  in a substantially horizontal (earth reference) arrangement. This arrangement results in the vertical axis  107  being orientated in a vertical (earth reference) direction. 
   Needle guide  102  has a slidable needle stop  120  which may be contoured on its top side to facilitate engagement with a human finger or thumb. Slidable needle stop  120  is preferably slidable along needle guide main body  106  which contains a first needle stop  110 . However, other arrangements between the slidable needle stop  120  and first needle stop  110  could be substituted. First needle stop  110  may be vertical and have a planar needle engagement surface  112  as shown, but other arrangements could be employed as well. 
   Also shown in  FIG. 1  are members  160  and  162 , which can form a pliable clip for attaching needle guide  102  to a bracket (not shown) coupled to a medical imaging transceiver when strap  104  is not used. 
   Now referring to  FIG. 2 , there is shown a partially cut-away side view of the needle guide  102  of  FIG. 1 . Needle guide  102  is shown having a spring  202 , which could be a simple metal or plastic spring, or it could be any resilient member or other apparatus capable of biasing sliding spring stop  122  so as to tend to minimize the width of needle gap  130 . Spring  202  is shown disposed between fixed spring stop  204  and sliding spring stop  122 . Needle guide  102  is also shown in the cut-away portion as having a needle guide main body  106 , first detent protrusion  206  and second detent protrusion  216  which are received by first detent protrusion receiving void  208  and second detent protrusion receiving void  218  both found in slidable needle stop  120 . Slidable needle stop  120  is shown having a top leading edge  220  and a bottom angled leading edge  222 . Preferably, the pressure exerted by spring  202  is sufficient to hold needle  101  stationary unless a force other than gravity acts upon it. 
   Now referring to  FIG. 3 , there is shown a bottom view of the needle guide  102  of  FIGS. 1 and 2 . 
   In operation, the apparatus and method of the present invention as described and shown in  FIGS. 1–3 , could function as follows: 
   Needle guide  102  is attached to medical imaging device  103  via medical imaging device retaining strap  104 . The needle guide  102  is readied for receipt of the needle  101  by sliding slidable needle stop  120  to create a gap sufficiently large to accommodate the particular biopsy needle used. The biopsy needle, such as needle  101 , is inserted into needle gap  130  and slidable needle stop  120  is released, thereby holding needle  101 . The needle  101  is then inserted into the patient. Medical imaging device  103  is used to create a first image of a portion of a human body. The medical imaging device  103  and needle guide  102  are then tilted with respect to the needle  101 . This provides a different angle of view of the end  1011  of the needle  101 . A second image is then created by the medical imaging device  103 . The needle may be held stationary and the medical imaging device  103  and needle guide  102  tilted, or vice versa. 
   The tilting of the needle  101  or needle guide  102  is done by applying a force between the two. As the angle of separation between the vertical axis  107  and the longitudinal axis of the needle  101  increases, the amount of contact between the needle  101  and planar needle engagement surface  112  and top leading edge  220  increases. This increases the friction on the needle  101 , thereby increasing the force needed to move the needle  101  to larger angular separations with respect to the needle guide  102 . 
   Throughout this description, reference is made to a medical imaging system, because it is believed that the beneficial aspects of the present invention would be most readily apparent when used in connection with medical imaging; however, it should be understood that the present invention is not intended to be limited to imaging, and should be hereby construed to include other medical tools, equipment and methodologies as well, where it is desirable to guide a needle. 
   Throughout this document, references are made to “vertical” and “horizontal”. These terms are intended to mean “substantially vertical” and “substantially horizontal”. Minor deviations from vertical and minor deviations from horizontal are intended to be included therein. Also see the above definition on vertical axis  107 . 
   It is thought that the method and apparatus of the present invention will be understood from the foregoing description and that it will be apparent that various changes may be made in the form, construct steps, and arrangement of the parts and steps thereof, without departing from the spirit and scope of the invention or sacrificing all of their material advantages. The form herein described is merely a preferred exemplary embodiment thereof.