Abstract:
A biopsy probe for the collection of at least one soft tissue sample from a surgical patient. The biopsy probe has a frame and an elongated piercing element having a proximal end attached to the distal end of the frame and a sharpened distal end for piercing tissue. The piercing element has a lumen extending at least partially therethrough. The probe also includes an elongated cutter disposed coaxially and slidably within the lumen of the piercing element. The cutter has a distal end for cutting a tissue sample, a proximal end and a body connecting the distal and proximal ends, wherein at least a portion of the body comprises a flexible member.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates, in general, to devices for tissue sampling and, more particularly, to improved biopsy probes for acquiring subcutaneous biopsies and for removing lesions.  
       BACKGROUND OF THE INVENTION  
       [0002]     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 are palpation, X-ray, MRI, CT, and ultrasound imaging. When the physician suspects that a 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 done. For a percutaneous biopsy, a needle-like instrument is used 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. Use of the percutaneous method in combination with artificial imaging devices such as X-ray and ultrasound has resulted in highly reliable diagnoses and treatments.  
         [0003]     Generally there are two ways to obtain percutaneously a portion of tissue from within the body, by aspiration or by core sampling. Aspiration of the tissue through a fine needle requires the tissue to be fragmented into small enough pieces to be withdrawn in a fluid medium. The method is less intrusive than other known sampling techniques, but one can only examine cells in the liquid (cytology) and not the cells and the structure (pathology). In core biopsy, a core or fragment of tissue is obtained for histologic examination 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. Core biopsy, however, is very useful in a number of conditions and is widely used by physicians.  
         [0004]     A number of biopsy devices for use in combination with artificial imaging devices are known in the field. An example of a core biopsy device using an artificial imaging system is described in U.S. Pat. Nos. 4,699,154, 4,944,308, and U.S. Pat. No. Re. 34,056. However, these types of spring-powered devices must re-puncture the breast or organ each time a sample is taken. An example of an aspiration device using an artificial imaging system is described in the following U.S. Pat. No.: 5,492,130 issued to Chiou on Feb. 20, 1996; U.S. Pat. No. 5,526,821 issued to Jamshidi on Jun. 18, 1996; U.S. Pat. No. 5,429,138 issue to Jamshidi on Jul. 4, 1995; and U.S. Pat. No. 5,027,827 issued to Cody, et al, on Jul. 2, 1991.  
         [0005]     Operator error can often be an issue with the above described devices. In addition there was a need for a device which could enable multiple sampling of the tissue without having to re-puncture the tissue for each sample. An example of such a product is described in U.S. Pat. No. 5,526,822 issued to Burbank, et al, on Jun. 18, 1996, which is hereby incorporated herein by reference. The Burbank et al. instrument is a type of image-guided, percutaneous, coring, breast biopsy instrument. It is vacuum-assisted, and some of the steps for retrieving the tissue samples have been automated. The physician uses this device to capture “actively” (using the vacuum) the tissue prior to severing it from the body. This allows for sampling tissues of varying hardness. The device can also be used to collect multiple samples in numerous positions about its longitudinal axis, and without needing to remove the device from the body. These features allow for substantial sampling of large lesions and complete removal of small ones. In the medical arts the instrument is commonly known as MAMMOTOME™.  
         [0006]     Numerous improvements to the Burbank et al. device have been described in co-pending and commonly assigned U.S. application Ser. No. 08/825,899, filed on Apr. 2, 1997, the disclosure of which is hereby incorporated herein by reference. This reference describes numerous improvements to the original invention including a molded tissue cassette housing which permits the handling and viewing of multiple tissue samples without physical contact by the instrument operator. Another improvement to the original device includes the interconnection of the housing to the piercing needle by a thumbwheel which permits the needle to rotate relative to the housing, thereby preventing the vacuum tube from wrapping about the housing.  
         [0007]     Other improvements to the above described device are disclosed in U.S. Pat. No. 6,007,497 issued to Huitema on Dec. 28, 1999, which is hereby incorporated herein by reference. This reference describes improvements to the fluid management capabilities of the system, resulting in part from the addition of sealing elements located in critical areas of the biopsy probe.  
         [0008]     In actual clinical use for breast biopsy, the MAMMOTOME instrument (probe and driver assembly) is mounted to the three axis positioning head of an x-ray imaging machine. The three axis positioning head is located in the area between the x-ray source and the image plate. The x-ray machines are outfitted with a computerized system which requires two x-ray images of the breast be taken with the x-ray source at two different positions in order for the computer to calculate the x, y and z axis location of the suspect abnormality. In order to take the stereo x-ray images the x-ray source must be conveniently movable. The x-ray source therefore is typically mounted to an arm which, at the end opposite the x-ray source, is pivotally mounted to the frame of the machine in the region of the image plate.  
         [0009]     To image the breast, the breast is placed between the x-ray source and the image plate, the breast being placed on the image plate. In order to take the necessary stereo images the clinician will manually position the x-ray source to one side and then the other of the center axis of the machine (typically 15-20 degrees to each side of the center axis), obtaining an x-ray image on each side of the breast. The computer will then, with great accuracy, calculate the precise x, y and z location of the suspect abnormality in the breast and automatically communicate to the clinician or directly to the positioning head the targeting coordinates for the biopsy device. The clinician can then manually, or automatically, position the biopsy probe into the breast at the precise location of the abnormality.  
         [0010]     There are generally two styles of x-ray machines in wide spread use for breast imaging. One style is known as “prone”, because the patient lies face down during the x-ray and biopsy procedures on a table that is configured horizontal to the floor. The other style, in more wide spread use, is the “upright”. The center axis of the upright imaging machine is configured vertical to the floor and the patient sits in front of the machine during the x-ray and biopsy procedures.  
         [0011]     The above described biopsy instruments mount to a three axis positioning head located between the x-ray source and image plate on the breast x-ray imaging machine. The distance between the x-ray source and imaging plate is known in the industry as the SID (Source to Image Distance). There is no standard SID in the industry and in fact the SID varies greatly from one x-ray machine manufacturer to another.  
         [0012]     This creates a problem for the manufacturers of devices, like the MAMMOTOME, which is intended to be mounted between the x-ray source and image plate of the x-ray imaging machine. In the case of the MAMMOTOME instrument with its length from the distal tip of the biopsy probe to the most proximal portion of the driver measuring approximately 41 centimeters, adequate mounting space has been found to exist on the prone style x-ray machines. However, on some of the more popular upright style x-ray imaging machines the SID has been found to be as little as 29 centimeters, obviously too small in which to mount the MAMMOTOME. What is needed, therefore, is a biopsy instrument configured to permit mounting on the shorter SID x-ray imaging machines.  
       SUMMARY OF THE INVENTION  
       [0013]     In accordance with the present invention, there is provided a biopsy probe for the collection of at least one soft tissue sample from a surgical patient. The biopsy probe has a frame and an elongated piercing element having a proximal end attached to the distal end of the frame and a sharpened distal end for piercing tissue. The piercing element has a lumen extending at least partially therethrough. The probe also includes an elongated cutter disposed coaxially and slidably within the lumen of the piercing element. The cutter has a distal end for cutting a tissue sample, a proximal end and a body connecting the distal and proximal ends, wherein at least a portion of the body comprises a flexible member. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     The novel features 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:  
         [0015]      FIG. 1  is an isometric view of a biopsy apparatus, showing the biopsy probe of  FIG. 2 , its insertion into a driver, and schematic representations of a control unit, vacuum sources, and three axis positioning head;  
         [0016]      FIG. 2  is an isometric view of a biopsy probe of the present invention;  
         [0017]      FIG. 3  is an exploded isometric view of the biopsy probe of  FIG. 2 ;  
         [0018]      FIG. 4  is an isometric view of a probe frame of the biopsy probe of  FIG. 2 ;  
         [0019]      FIG. 5  is a longitudinal sectional view of the probe frame of  FIG. 4  illustrating the internal structures assembled into its distal and proximal ends.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]     As best shown in  FIG. 1 , the present invention is a surgical biopsy apparatus  12  for a minimally invasively acquiring repeated subcutaneous biopsies. In the present invention, surgical biopsy apparatus  12  generally comprises a probe  10  for insertion within a surgical patient for extraction of a tissue sample therefrom. Apparatus  12  further includes a powered probe driver  100 , a three axis positioning head  98 , a control unit  96 , and a first and second tube in fluid communication with a first, and second reservoir, respectively. In the preferred embodiment, reservoirs  90  and  94  are connected to at least one vacuum source. Probe  10  of surgical biopsy apparatus  12  is removably mounted to powered probe driver  100 . The elements shown schematically as boxes in  FIG. 1  are well known in the art and are described in the herein incorporated references.  
         [0021]     Driver  100  is well known in the art and includes a housing  109  having a moveable cover  108  hingedly attached thereto. Within housing  109  there is a housing mount fork  102  for receiving probe  10 . Housing  109  also included a cutter advance fork  112  for positioning cutter gear  59 , and an elongated driver gear  106  to mate with and rotate cutter  50 . Driver  100  is attached to a three axis positioning head  98  which is connected to an x-ray imaging machine having a stereotactic guidance system (not shown). This positioning/guidance system is for moving probe  10  and driver  100  so that the apparatus pierces the tissue at the correct location in order to sample the target lesion. Housing  109  also has a cutter advance knob  113  which is manually actuated to obtain the tissue sample. This feature will be discussed in greater detail below.  
         [0022]     Control unit  96  is used to control the sequence of actions performed by surgical biopsy apparatus  12  in order to obtain the biopsy sample from a surgical patient. As will be appreciated by those skilled in the art, and as discussed in the hereinbefore incorporated references, control unit  96  preferably controls the application of a vacuum to probe  10 , and controls the activation of the cutter motor (not shown) within driver  100 .  
         [0023]     Attention is now drawn to  FIG. 2  which is an isometric view of the preferred embodiment of probe  10 . Probe  10  is a coaxial assembly of three elongated elements: a piercer  20 , a cutter  50 , and a tissue remover  60 . Tissue remover  60  moves slideably within cutter  50  which, in turn, moves slideably within frame  40  and piercer  20 . Cutter  50  and tissue remover  60  contain flexible elements, as will be described later. Probe  10  generally is used as follows: The skin of a surgical patient is disinfected. A local anesthetic such as lidocaine hydrochloride is injected by hypodermic needle into the tissue. A small incision is made in the skin of the surgical patient. Then piercer  20  is placed into that incision and pierced into the tissue of the surgical patient. Piercer  20  is advanced to the tissue area of interest by the movement of three axis positioning head  98 . During this step cutter  50  is completely advanced in its distal direction. Once the tissue of interest is accessed by piercer  20 , cutter  50  is partially retracted in the proximal direction and the tissue to be extracted is drawn by vacuum into port  26  on distal end  22  of probe  10 . Cutter  50  is then actuated by the cutter motor of driver  100  and manually advanced distally using cutter advance knob  113 . This severs the tissue sample captured in distal end  22  of probe  10 . Afterwards, cutter  50  is manually retracted in the proximal direction, transporting the tissue sample to outside the patient&#39;s body. Tissue remover  60  then releases or “knocks-out” the tissue sample from cutter  50 , so that the tissue sample may be retrieved for analysis.  
         [0024]     Referring to  FIGS. 2 through 4 , piercer  20  includes a frame  40  which may be made from a rigid, medical grade plastic. Frame  40  is generally arcuate in shape, forming an arc of approximately ninety degrees in the preferred embodiment, and may be more or less as may be dictated by the mounting needs for the x-ray imaging machine. Frame  40  has a distal end  48  and a proximal end  49 . Frame hole  45  (See  FIG. 5 ) extends longitudinally through frame bushing  46  communicating between the distal end  48  and proximal end  49  of frame  40 . A pair of mounting fins  44  are located on proximal end  49  of frame  40 . Mounting fins  44  are removably inserted into a mounting fork  102  of driver  100  as depicted in  FIG. 1 , thus anchoring probe  10  to driver  100 .  
         [0025]     Teeth  38 , which comprise a plurality of raised ribs, and marker  39 , a single raised rib, are located at the distal end  48  of frame  40  and interface with positioning wheel  30 , which will be described in more detail later. Tissue sampling surface  47  at the distal end  48  of frame  40  is where a tissue sample extracted from within the surgical patient is removed from probe  10 .  
         [0026]     Tubular piercing element  25  is well known in the art and has a proximal end  24  and a distal end  22  and is rotatably attached to the proximal end  48  of frame  40  by a hub  2  (See  FIG. 5 ) and a positioning wheel  30 . Piercing element  25  is preferably made from plastic or stainless steel and includes an upper lumen  21  and a lower lumen  23 . Rectangular port  26  on distal end  22  of piercing element  25  is located on upper lumen  21  and is provided for receiving the tissue that is to be extracted from the surgical patient. Rotation of positioning wheel  30  by the surgeon allows positioning of rectangular port  26  in distal end  22  of piercer  20 . A positional indicator  31  on wheel  30  may be referenced to a marker  39  on frame  40  of probe  10 . By changing the position of port  26 , the surgeon may access tissue from anywhere around distal end  22  of piercer  20 . Piercing tip  28  is attached to distal end  22  of piercing element  25  and pierces into the tissue of the surgical patient. Piercer  20  further comprises a lower lumen  23  which has a plurality of small holes (not shown) in distal end  22  for the communication of port  26  to first reservoir  90 . In the present embodiment, this first reservoir is a vacuum source so that the prolapse of tissue into port  26  is greatly enhanced.  
         [0027]     A plurality of teeth  38  are located around the periphery of distal end  48  of frame  40 . Teeth  38  are for interaction with flutes  32  (not shown) of positioning wheel  30  (see  FIG. 1 ) so that a tactile feedback is provided to the user while adjusting the location of port  26  on distal end  22  of piercer  20 . In addition to the tactile feedback, teeth  38  are a holding means for the orientation of port  26 , and also a referencing means. That is, the surgeon may count the number of “detents” felt when rotating positioning wheel  30 , while looking at the relationship between positional indicator  31  on wheel  30  and marker  39  on frame  40 , in order to understand the radial orientation of port  26  on distal end  22  of piercer  20 .  
         [0028]     Now referring again to  FIGS. 1 and 3 , cutter  50  comprises a distal end  52 , a proximal end  58 , and a flexible member extending therebetween. Cutter  50  further comprises a cutter shank  56  having a distal end  57  fixedly attached to a proximal end  54  of a hollow flexible cutter tube  53 . Flexible cutter tube  53  can be made of PVC or any other flexible thermoplastic polymer or a superelastic alloy such as nitinol. In an alternate embodiment flexible cutter tube  53  is made of a tubular shape constructed of wound stainless steel wire, similar to a compression spring. A longitudinal passage through cutter shank  56  (not visible) communicates with a longitudinal passage through flexible cutter tube  53 . On the distal end of cutter  50  is a cutter blade  51 . Cutter blade  51  has a distal end  65  and proximal end  66 . Cutter blade  51  is preferably made by the sharpening of the circumference of distal end  65  of cutter blade  51 , which is preferably made of a stainless steel. Proximal end  66  of cutter blade  51  is fixedly attached to distal end  67  of flexible cutter tube  53 . A longitudinal passage through cutter blade  51  communicates with a longitudinal passage through flexible cutter tube  53 . On proximal end  58  of cutter  50  is a cutter gear  59 , which is preferably integrally molded with cutter shank  56 . A proximal cutter seal  114  is attached to the most proximal end of cutter  50 .  
         [0029]     Cutter gear  59  is for operational engagement with an elongated gear  106  of driver  100 . When probe  10  is inserted into driver  100 , cutter gear  59  is positioned into cutter advance fork  112  of the driver. Cutter advance fork  112  is attached to cutter advance knob  113  so that movement of knob  113  causes the like movement of cutter  50 . Cutter  50  reciprocates axially within upper lumen  21  of piercer  20  as the surgeon manually operates advancing knob  113 . As cutter  50  is moved distal and proximal by operation of cutter advance knob  113 , cutter gear  59  moves along elongated gear  106  of driver  100 , while maintaining operational engagement. The electric motor (not shown) of the driver rotates cutter  50  at a high rate of speed.  
         [0030]     As best illustrated in  FIG. 3 , tissue remover  60  comprises a remover tube  63 , which has a proximal end  64 , a distal end  62 , and a longitudinal axis extending therebetween. Tissue remover  60  slides freely through proximal cutter seal  114 . On proximal end  64  of remover tube  63  is attached a valve  70  having a distal end  72 , a proximal end  74  which contains a Luer connector, and a passageway therethrough. Valve  70  provides for the flow of air and fluids from tissue remover  60  to second reservoir  94  via second tube  95  and a connector  97  (see  FIG. 1 ). Remover tube  63  is hollow and in the present embodiment made of flexible PVC or other flexible thermoplastic resin. In an alternate embodiment, since remover tube  63  is held fixed with reference to probe frame  40 , remover tube  63  is made of a rigid material such as stainless steel and pre-formed in an arcuate shape to match the arc of probe frame  40 . A distal tip  61  (also referred to simply as a structure) on distal end  62  of remover tube  63  is configured so as to allow the passage of air and fluids and to block the passage of tissue particles larger than what may pass through tissue remover  60  and valve  70 . Distal tip  61  prevents the loss of tissue into the reservoir, which may otherwise be collected for pathological analysis. The length of remover tube  63  is such that when cutter  50  is retracted to the first position, distal tip  61  of remover tube  63  is approximately adjacent to cutter blade distal end  65  of cutter blade  51 . This arrangement allows the tissue sample retrieved in distal end  52  of cutter  50  to be forced out of the same by distal tip  61  of tissue remover  60  when cutter  50  is retracted to the first position. The tissue sample may then drop onto tissue sample surface  47  of probe  10 .  
         [0031]     Referring now to  FIG. 5 , flexible cutter tube  53  fits closely yet slides freely in frame hole  45  which extends longitudinally through frame bushing  46  of piercer  20 . When cutter  50  is retracted to its most proximal position, cutter blade  51  of cutter  50  is approximately adjacent to frame surface  82  of piercer  20  so as to allow free access to sampling surface  47  (See  FIG. 4 ) for retrieval of the tissue sample.  
         [0032]     Distal frame seal  1  is shown assembled into distal end  48  of frame  40  and rotatably supports proximal end  24  of piercing element  25 . Distal frame seal  1  comprises hub  2  and a first O-ring  120  and a second O-ring  121 . Hub  2  further comprises a hub step  19 , wherein hub step  19  is a supporting means for positioning wheel  30  (see  FIG. 3 ). A first radial space  122 , which is occupied by part of distal frame seal  1 , is defined by the radial clearance between piercer  20  (partially shown) and proximal end  48  of frame  40 . A lower lumen vacuum boss  41  is in alignment between two O-rings  120  and  121  so as to allow vacuum to be delivered through passages  35  and into opening  6  of distal frame seal  1 . First tube  91  (see  FIG. 1 ) from first reservoir  90  is a flexible, medical grade tube which may fit tightly over vacuum boss  41 . Proximal end  24  of lower lumen  23  of piercing element  25  is inserted into opening  6  of distal frame seal  1  so that the vacuum may be delivered through lower lumen  23  and to port  26  on distal end  22  of piercer  20 .  
         [0033]     Proximal frame seal  11  is shown assembled into proximal end  49  of frame  40  and is held in position by a protrusion projecting into hole  36  in frame  40 . The proximal frame seal occupies a second radial space  124  defined by the clearance between flexible cutter tube  53  and proximal end  49  of frame  40 . Proximal frame seal  11  substantially prevents the flow of fluids through the second radial space.  
         [0034]     It should be noted that second reservoir  94  is a vacuum source which facilitates the removal of the fluids from within probe  10 , and which facilitates the transport of the tissue sample from port  26  to tissue sampling surface  47  (see  FIG. 1 ). Because tissue remover  60  is inserted within cutter  50  which is inserted in upper lumen  21  of piercer  20 , the vacuum source is connected to upper lumen  21  as well and assists in drawing tissue into port  26  prior to cutting of the tissue by cutter blade  51 . In addition to the removal of fluids from probe  10 , the vacuum provides a means of releasably attaching the tissue sample to the end of tissue remover  60  so that once severed, the sample may be held in distal end  52  of flexible cutter tube  53  and transported from port  26  of piercer  20  to outside the patient&#39;s body to tissue sampling surface  47  of probe  10 .  
         [0035]     While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments 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 invention. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.