Abstract:
A biopsy device and method are provided for obtaining a tissue sample, such as a breast tissue biopsy sample. The biopsy device includes a disposable probe assembly with an outer cannula having a distal piercing tip, a cutter lumen, and a cutter tube that rotates and translates past a side aperture in the outer cannula to sever a tissue sample. The biopsy device also includes a reusable hand piece with an integral motor and power source to make a convenient, untethered control for use with ultrasonic imaging. The reusable hand piece incorporates a probe oscillation mode to assist when inserting the distal piercing tip into tissue. A straw stacking assembly is automatically positioned by the reusable hand piece to retract multiple samples with a single probe insertion as well as giving a visual indication to the surgeon of the number of samples that have been taken.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates in general to biopsy devices, and more particularly biopsy devices having a cutter for severing tissue, and even more particularly to biopsy ices for multiple sampling with a probe remaining inserted.  
       BACKGROUND OF THE INVENTION  
       [0002]     When a suspicious tissue mass is discovered in a patient&#39;s breast through examination, ultrasound, MRI, X-ray imaging or the like, it is often necessary to perform a biopsy procedure to remove one or more samples of that tissue in order to determine whether the mass contains cancerous cells. A biopsy may be performed using an open or percutaneous method.  
         [0003]     An open biopsy is performed by making a large incision in the breast and removing either the entire mass, called an excisional biopsy, or a substantial portion of it, own as an incisional biopsy. An open biopsy is a surgical procedure that is usually done as an outpatient procedure in a hospital or a surgical center, involving both high cost and a high level of trauma to the patient. Open biopsy carries a relatively higher risk of infection and bleeding than does percutaneous biopsy, and the disfigurement that sometimes results from an open biopsy may make it difficult to read future mammograms. Further, the aesthetic considerations of the patient make open biopsy even less appealing due to the risk of disfigurement. Given that a high percentage of biopsies show that the suspicious tissue mass is not cancerous, the downsides of the open biopsy procedure render this method inappropriate in many cases.  
         [0004]     Percutaneous biopsy, to the contrary, is much less invasive than open biopsy. percutaneous biopsy may be performed using fine needle aspiration (FNA) or core needle biopsy. In FNA, a Very thin needle is used to withdraw fluid and cells from the suspicious tissue mass. This method has an advantage in that it is very low-pain, so low-pain that local anesthetic is not always used because the application of it may be more painful than the FNA itself. However, a shortcoming of FNA is that only a small number of cells are obtained through the procedure, rendering it relatively less useful in analyzing the suspicious tissue and making an assessment of the progression of the cancer less simple if the sample is found to be malignant.  
         [0005]     During a core needle biopsy, a small tissue sample is removed allowing for a pathological assessment of the tissue, including an assessment of the progression of any cancerous cells that are found. The following patent documents disclose various core biopsy devices and are incorporated herein by reference in their entirety: U.S. Pat. No. 6,273,862 issued Aug. 14, 2001; U.S. Pat. No. 6,231,522 issued May 15, 2001; U.S. Pat. No. 6,228,055 issued May 8, 2001; U.S. Pat. No. 6,120,462 issued Sep. 19, 2000; U.S. Pat. No. 6,086,544 issued Jul. 11, 2000; U.S. Pat. No. 6,077,230 issued Jun. 20, 2000; U.S. Pat. No. 6,017,316 issued Jan. 25, 2000; U.S. Pat. No. 6,007,497 issued Dec. 28, 1999; U.S. Pat. No. 5,980,469 issued Nov. 9, 1999; U.S. Pat. No. 5,964,716 issued Oct. 12, 1999; U.S. Pat. No. 5,928,164 issued Jul. 27, 1999; U.S. Pat. No. 5,775,333 issued Jul. 7, 1998; U.S. Pat. No. 5,769,086 issued Jun. 23, 1998; U.S. Pat. No. 5,649,547 issued Jul. 22, 1997; U.S. Pat. No. 5,526,822 issued Jun. 18, 1996; and U.S. Patent Application 2003/0199753 published Oct. 23, 2003 to Hibner et al.  
         [0006]     At present, a biopsy instrument marketed under the tradename MAMMOTOME is commercially available from ETHICON ENDO-SURGERY, INC. for use in obtaining breast biopsy samples. These devices generally retrieve multiple core biopsy samples from one insertion into breast tissue with vacuum assistance. In particular, a cutter tube is extended into a probe to cut tissue prolapsed into a side aperture under vacuum assistance and then the cutter tube is fully retracted between cuts to extract the sample.  
         [0007]     With a long probe, the rate of sample taking is limited not only by the time required to rotate or reposition the probe but also by the time needed to translate the cutter. As an alternative to this “long stroke” biopsy device, a “short stroke” biopsy device is described in the following commonly assigned patent applications: U.S. patent application Ser. No. 10/676,944, “Biopsy Instrument with Internal Specimen Collection Mechanism” filed Sep. 30, 2003 in the name of Hibner et al.; and U.S. patent application Ser. No. 10/732,843, “Biopsy Device with Sample Tube” filed Dec. 10, 2003 in the name of Cicenas et al. The cutter is cycled across the side aperture, reducing the sample time. Several alternative specimen collection mechanisms are described that draw samples through the cutter tube, all of which allow for taking multiple samples without removing the probe from the breast.  
         [0008]     Even given the many advantages of such multiple sample taking core biopsy devices, in certain applications some surgeons continue to use less expensive biopsy devices guided in real time by an ultrasonic system. These simple biopsy systems omit a full function control console that operates the cutter and vacuum assistance. Instead, a manually controlled hand piece advances a cutter by either stored spring force, a constant pneumatic pressure source, or motor power. Then the surgeon activates a cutter motor to effect the tissue sample. Thus, the surgeon is challenged to maintain the biopsy probe at a desired surgical site while manipulating the patient&#39;s breast.  
         [0009]     Consequently, it would be desirable to provide for a core biopsy device with a motorized cutter that provides increased functionality such as one-handed operation with assisted multiple sample retrieval with only one insertion of the probe, yet be able to retain the economical aspects of simple core biopsy devices that lack elaborate remote control systems.  
         [0010]     Spring-fired core needle biopsy devices rely upon a firing mechanism that thrusts forward a needle and a cutter to penetrate the tissue and to obtain a tissue sample rather than palpitating tissue to prolapse into a side aperture of a probe. Frequently, a surgeon may encounter an area of dense tissue that is more difficult to penetrate than the surrounding tissue during core needle biopsy. In particular, the lesion or tissue mass being targeted in the biopsy procedure may be difficult to penetrate, requiring the physician to push the biopsy needle with considerable force and/or speed in an attempt to penetrate the lesion and collect a sample.  
         [0011]     When encountering such an area of dense tissue, it is common for surgeons using the type of firing core needle biopsy device described above to fire the device in order to penetrate the lesion and obtain a sample. However, due to the length of the firing stroke of such devices, which may be as long as 0.75 inches, it is nearly impossible for the surgeon to control the travel of the needle after firing. Consequently, the long needle stroke may cause uncertainty as to the needle tip location post fire. This may cause the surgeon to obtain a sample from the wrong area. In addition to missing the targeted tissue, long firing strokes may cause the needle to puncture the chest wall or pierce the skin, particularly when the targeted area is near the patient&#39;s chest wall. Even if the skin is not pierced, the long travel of the needle, along with the likelihood that the needle will be pushed off course by the force of the firing stroke, may lead to needlessly increased trauma for the patient. These spring-fired biopsy devices also yield a single sample per insertion, thus limiting the amount of diagnostic and therapeutic treatment that may be achieved without the increased discomfort and tissue trauma from repeated insertions. Based on surgeons&#39; use of the long firing stroke feature of current devices to aid in penetrating tissue lesions, it is clear that the medical community sees the benefit of firing assistance when inserting a probe to the desired location.  
         [0012]     In commonly-owned and co-pending U.S. patent application Ser. No. 11/035,873, BIOPSY INSTRUMENT WITH IMPROVED NEEDLE PENETRATION to Beckman, et al., filed on Jan. 10, 2005, manual mechanisms are disclosed that impart small reciprocating motions to the probe of a core biopsy device to render assistance in penetrating tissue, yet cutting is performed after the probe is properly positioned, thus avoiding taking samples from the wrong location. While there are advantages to having such cutting assistance imparted by manual actuation, it is generally desirable to alleviate the need for the surgeon to perform this additional action while having to manually position the biopsy device.  
         [0013]     Additionally, it would be desirable to provide for a hand-held core biopsy device that automatically imparts a motion to the probe that assists in penetrating dense tissue yet does not take a sample.  
       SUMMARY OF THE INVENTION  
       [0014]     The present invention addresses these and other problems of the prior art by providing a core biopsy device having a probe assembly with a probe support structure that holds a probe having a side aperture. A cutter tube is slidingly received by the probe and sized to translate across the side aperture to sever prolapsed tissue. A hand piece includes a hand piece support structure having a lateral engaging portion that receives the probe assembly. A lead screw is attached for rotation to the hand piece support structure. A cutter carriage is longitudinally translated by rotation of the lead screw thereby translating the cutter tube. Thereby, an economical incorporation of a replaceable probe and cutter tube into a laterally mounted assembly allows reuse of a powered hand piece.  
         [0015]     In one aspect consistent with other aspects of the invention, a biopsy device includes a frame supported core biopsy probe, the frame spring biased to a housing. A motor driven cam wheel coupled to the housing urges the frame against the spring bias, imparting a reciprocating longitudinal movement to the core biopsy probe to assist in penetrating dense tissue.  
         [0016]     In another aspect of the invention, a biopsy device includes the replaceable probe assembly that engages a motor-driven carriage assembly that sequences distal translation of a rotated cutter tube with vacuum assistance sequenced from a constant vacuum source by the position of the cutter tube. Thereby, advantages of consistent prolapse of tissue into the probe is achieved with a commonly available vacuum source.  
         [0017]     In yet another aspect of the invention, a biopsy device obtains tissue samples that prolapse into a sample aperture in a probe needle that are then severed by a translating cutter tube received in the probe needle. A sample straw is proximally received in the cutter tube to capture these severed tissue samples. As these severed tissue samples are sequentially stacked in the sample straw, an indicator tube is forced proximally out of the sample straw to give a visual indication as to the number of tissue samples obtained. The stored tissue samples advantageously are maintained in the order taken, which aids in further diagnostic assessment.  
         [0018]     In yet a further aspect of the invention, a biopsy device obtains tissue samples that prolapse into a sample aperture in a probe needle that are then severed by a translating cutter tube received in the probe needle. A storage tube communicates with a proximal end of the cutter tube so that a vacuum control may apply a vacuum through the storage tube and the cutter tube to retract severed tissue samples there through. The stored tissue samples are also advantageously maintained in the order taken to aid in further diagnostic assessment.  
         [0019]     In yet an additional aspect of the invention, a hand piece has a hand piece support structure having a lateral engaging portion operatively configured to engage a probe support structure of a selected one of a first and second probe assemblies. A lead screw translates a cutter carriage that advances a cutter tube within a probe needle of the selected probe assembly. One probe assembly includes a sample straw that is proximally advanced by a cutter carriage of the hand piece that is longitudinally translated by rotation of the lead screw to retract tissue samples. The other probe assembly has a storage tube that communicates with the cutter tube for pneumatically retracting tissue samples. Thereby, economical incorporation of a common hand piece may be realized while providing the clinical flexibility of choosing a disposable probe assembly with a desired approach to tissue sample retraction.  
         [0020]     In yet another aspect of the invention, a method of obtaining core biopsy samples adantageously maintains samples taken in a sequential stack to enhance diagnostic assessment thereof. This orientation is achieved by inserting a core biopsy needle into tissue, prolapsing tissue into an opening of the core biopsy needle and then translating a cutter tube through the core biopsy needle to sever the prolapsed tissue to form a first tissue sample. These steps are repeated with each tissue sample being sequentially urged into a sample lumen that proximally communicates with the cutter tube. Thereby, the sequential stacking is maintained for lateral retrieval and analysis.  
         [0021]     These and other objects and advantages of the present invention shall be made apparent from the accompanying drawings and the description thereof. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]     While the specification concludes with claims particularly pointing out and distinctly claiming the present invention, it is believed the same will be better understood by reference to the following description, taken in conjunction with the accompanying drawings in which:  
         [0023]      FIG. 1  is a top perspective view of a biopsy device with a disposable probe assembly detached from a reusable hand piece, the latter with a housing shown in phantom;  
         [0024]      FIG. 2  is a bottom perspective view of the biopsy device of  FIG. 1 ;  
         [0025]      FIG. 3  is a disassembled perspective view of the disposable probe assembly  FIG. 1 ;  
         [0026]      FIG. 4  is a disassembled perspective view of the reusable hand piece of FIG. of  FIG. 1 ;  
         [0027]      FIG. 5  is a top view of an assembled biopsy device of  FIG. 1 ;  
         [0028]      FIG. 6  is a front view of the biopsy device of  FIG. 5 ;  
         [0029]      FIG. 7  is a left side view in elevation of the biopsy device of  FIG. 5 ;  
         [0030]      FIG. 8  is a bottom view of the biopsy device of  FIG. 5 ;  
         [0031]      FIG. 9  is a front view of the biopsy device of  FIG. 7  taken in cross section along lines  9 - 9  through a distal cutter carriage engagement to a cutter gear;  
         [0032]      FIG. 10  is a front view of the biopsy device of  FIG. 7  taken in cross section along lines  10 - 10  through a proximal straw carriage and stacking straw assembly;  
         [0033]      FIG. 11  is a front view of the biopsy device of  FIG. 7  taken in cross section along lines  11 - 11  through a bayonet locking member disengaged from the stacking straw assembly by attaching the disposable probe assembly to the reusable hand piece;  
         [0034]      FIG. 12  is a bottom view of the biopsy device of  FIG. 7  taken in horizontal cross section along lines  12 - 12  through the probe and stacking straw assembly;  
         [0035]      FIG. 13  is a detail perspective view of a slide button, sliding spur gear, and tissue penetration gear of the biopsy device of  FIG. 5 ;  
         [0036]      FIG. 14  is a left side view of the probe inserted into tissue of the biopsy device of  FIG. 12  in longitudinal cross section exposing the distally translated cutter tube, elongate straw, and indicator tube;  
         [0037]      FIG. 15  is a left perspective view of the biopsy device of  FIG. 12  with the housing removed;  
         [0038]      FIG. 16  is a bottom view of the biopsy device of  FIG. 6  taken in cross section along staggered lines  16 - 16  through a lead (translation) screw and a slide pin engaged to the cutter and straw carriages;  
         [0039]      FIG. 17  is a bottom view of the biopsy device of  FIG. 6  taken in horizontal cross section along lines  17 - 17  through a pneumatic valve that sequences vacuum assistance corresponding to cutter position;  
         [0040]      FIG. 18  is a bottom of the biopsy device of  FIG. 16  in cross section after proximal retraction of the straw carriage;  
         [0041]      FIG. 19  is a left perspective detail view of the carriages, lead screw, and sliding pin of the biopsy device of  FIG. 18  with the housing removed;  
         [0042]      FIG. 20  is a left view in elevation of the probe in longitudinal cross section of the biopsy device of  FIG. 18  with the elongate straw and indicator tube retracted;  
         [0043]      FIG. 21  is a bottom of the biopsy device of  FIG. 18  in cross section with both the cutter carriage and straw carriage retracted;  
         [0044]      FIG. 22  is a left perspective detail view of the carriages, lead screw, and sliding pin of the biopsy device of  FIG. 21 ;  
         [0045]      FIG. 23  is a left view in elevation of the probe in longitudinal cross section of the biopsy device of  FIG. 21  with vacuum assistance prolapsing tissue into the side aperture;  
         [0046]      FIG. 24  is a bottom view of the pneumatic valve in horizontal cross section of the biopsy device of  FIG. 21 ;  
         [0047]      FIG. 25  is a left perspective detail view of the carriages, lead screw and sliding pin of the biopsy device of  FIG. 21  after distal translation of the cutter carriage;  
         [0048]      FIG. 26  is a left side view of the probe in longitudinal cross section of the biopsy device of  FIG. 25  after severing tissue;  
         [0049]      FIG. 27  is a left side view of the probe in longitudinal cross section of the biopsy device of  FIG. 26  with distally translated cutter and straw carriages after taking two samples held in the elongate straw by bent up tabs with corresponding proximal extrusion of the indicator tube;  
         [0050]      FIG. 28  is a left side detail view in elevation of a proximal portion of the stacking straw assembly including a mechanical diode preventing distal movement of the indicator tube into the elongate straw;  
         [0051]      FIG. 29  is a perspective view of the straw carriage and an engaged stacking straw assembly;  
         [0052]      FIG. 30  is a perspective view of the straw carriage and a disengaged stacking straw assembly;  
         [0053]      FIG. 31  is an aft view in elevation of the biopsy device of  FIG. 30  with the disengaged stacking straw assembly;  
         [0054]      FIG. 32  is an aft view in elevation of the biopsy device of  FIG. 29  with the stacking straw assembly rotated a quarter turn into engagement;  
         [0055]      FIG. 33  is a perspective view of the stacking straw assembly of the biopsy device of  FIG. 1  after removal and peeling apart to access samples;  
         [0056]      FIG. 34  is a top perspective view of an alternative probe assembly with omitted vacuum assistance instead relying on external hand palpitation of tissue to prolapse the tissue into the side aperture of the probe for the biopsy device of FIG. I to acquire tissue samples;  
         [0057]      FIG. 35  is a bottom perspective view of the alternative probe assembly of  FIG. 34 ;  
         [0058]      FIG. 36  is a disassembled perspective view of the alternative probe assembly  FIG. 34 ;  
         [0059]      FIG. 37  is a disassembled perspective view of an alternative disposable assembly with a straw assembly having a luer fitting for the reusable hand piece of  FIG. 1 ;  
         [0060]      FIG. 38  is a left side view of an alternative probe inserted into tissue for the reusable hand piece of  FIG. 1  in longitudinal cross section exposing the distally translated cutter tube, elongate straw, and indicator tube and with through holes in a probe tube;  
         [0061]      FIG. 39  is a left side view of another alternative probe inserted into tissue for the hand piece of  FIG. 1  that employs pneumatic pressure to retrieve tissue samples through the cutter tube rather than a straw assembly;  
         [0062]      FIG. 40  is a top left perspective view of an alternative proximal stacking disposable assembly incorporating the probe of  FIG. 39  and being in an initial state before use;  
         [0063]      FIG. 41  is a bottom right perspective view of the alternative proximal stacking disposable assembly of  FIG. 40 ;  
         [0064]      FIG. 42  is a disassembled perspective view of the alternative proximal stacking disposable assembly of  FIG. 40 ;  
         [0065]      FIG. 43  is a top left perspective view of the alternative proximal stacking disposable assembly of  FIG. 40  with a retrieved tissue sample and a retracted cutter;  
         [0066]      FIG. 44  is a bottom right perspective view of the alternative proximal stacking disposable assembly of  FIG. 43 ;  
         [0067]      FIG. 45  is a top left perspective view of a flexible, peel-apart external tissue lumen after actuating a lumen peel-apart tab to separate an inwardly open channel holding retrieved tissue samples from an elongate seal;  
         [0068]      FIG. 46  is a left aft perspective view of the sample holding portion of the alternative proximal stacking disposable assembly of  FIG. 40  with a distal portion transversely cut away to expose vacuum and tissue lumens;  
         [0069]      FIG. 47  is a disassembled perspective of the sample holding portion of the alternative proximal stacking disposable assembly of  FIG. 40 ;  
         [0070]      FIG. 48  is a left perspective view of the sample holding portion of the alternative proximal stacking disposable assembly of  FIG. 40  formed of a transparent material exposing retrieved tissue samples;  
         [0071]      FIG. 49  is a top right perspective view of a reciprocating member of the sample holding portion of the alternative proximal stacking disposable assembly of  FIG. 40 ;  
         [0072]      FIG. 50  is a perspective view of a translating flexible rod of the sample holding portion of the alternative proximal stacking disposable assembly of  FIG. 40 ;  
         [0073]      FIG. 51  is a left side view in longitudinal cross section taken through the translating flexible rod of the sample holding portion of the alternative proximal stacking disposable assembly of  FIG. 40 ;  
         [0074]      FIG. 52  is a left perspective view of the sample holding portion of the alternative proximal stacking disposable assembly of  FIG. 40  with a retracted reciprocating portion;  
         [0075]      FIG. 53  is a left perspective view of the sample holding portion of the alternative proximal stacking disposable assembly of  FIG. 40  with the reciprocating portion subsequently distally advanced; and  
         [0076]      FIG. 54  is a left perspective view of the sample holding portion of the alternative proximal stacking disposable assembly of  FIG. 40  with the reciprocating portion subsequently proximally retracted. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0077]     In  FIGS. 1-4 , a biopsy device  10  has a reusable hand piece  12  and a disposable probe  14  that enables economical taking of multiple percutaneous core biopsy samples by accessing a standard medical vacuum pump or wall-mounted vacuum access port (not shown) through an interfacing vacuum conduit  16 . In the illustrative version, the hand piece  12  is self-powered and suitable for use in conjunction with ultrasonic diagnostic imaging. The disposable probe  14  reduces the portion of biopsy device  10  that requires protective packaging to avoid contact with sharp surfaces and to keep it sterile prior to use. Further economy is accomplished by reducing the portion of the biopsy device  10  that is disposed as medical waste between uses. Movable components of the disposable probe  14  are advantageously locked until mounted in an access trough  18  formed in a housing  20  of the reusable hand piece  12 . It should be appreciated that one or more standard mechanical, pneumatic, or electrical latches (not shown) may be integrated into the biopsy device  10  to secure the disposable probe  14  to the reusable hand piece  12 .  
         [0078]     With particular reference to  FIG. 3 , the disposable probe assembly  14  includes a substantially rectangular cover  22  sized to close the access trough recess  18  ( FIGS. 2, 4 ). An end slot  24  formed in the cover  20  ( FIGS. 1-2 ,  4 ) is closed by a probe union sleeve  26  attached to an inner surface  27  of the substantially rectangular cover  22 . A core biopsy needle (“probe”) assembly  28  passes longitudinally through the probe union sleeve  26  and is formed by a probe tube  30  with underlying vacuum lumen  32  that communicates with a side aperture  34  through holes  35  ( FIG. 23 ) near a distal opening  36  of the probe tube  30  that is closed by a piercing tip  38 . A cutter tube  40  is sized to closely fit and translate within an inner diameter (i.e., cutter lumen) of the probe tube  30  with a length sufficient to close the side aperture  34  with a proximal end  42  extending from the probe union sleeve  26  to attach to a cutter gear  44 , as depicted in  FIG. 1 .  
         [0079]     Proximal to the probe union sleeve  26  is an elongate slot  50  that is part of a vacuum assist valve assembly  52 . The cutter gear  44  includes distal and proximal annular recesses  54 ,  56  flanking spur gear teeth  58  that engage the reusable hand piece  12  as described below. A more distal annular recess  60  is gripped by a post  62  that is engaged to longitudinally translate in an elongate post slot  64  of a distal portion  66  of a vacuum valve actuator  68 . A cylindrical proximal portion  70  of the vacuum valve actuator  68  has distal and proximal O-ring grooves  72 ,  73  that respectively retain distal and proximal dynamic O-ring seals  74 ,  75  that move within a distally open cylindrical valve bore  76  of a valve body  78  molded onto an outer surface  79  of the substantially rectangular cover  22  ( FIG. 2 ).  
         [0080]     As described below, the vacuum valve actuator  68  selectively allows communication between a proximal port  80 , a center port  82 , and a distal port  84  ( FIG. 2 ). In particular, with the cutter gear  44  retracted, the proximal and center ports  80 ,  82  are in communication. With the cutter gear translated distally, the center and distal ports  82 ,  84  communicate. The center port  82  is attached to a distal vacuum conduit  86  whose other end is connected through the rectangular cover  22  to the probe union sleeve  26 . It should be appreciated that the probe union sleeve  26  includes pneumatic passages that communicate between a proximal end of the vacuum lumen  32  and the distal vacuum conduit  86 . The distal port  84  is attached to a hose nib  88  that is exposed to atmospheric pressure. Hose nib  88  may include an air and/or saline filter. Alternatively, hose nib  88  may be connected to a positive pressure source (e.g., fluid pump) or a negative pressure source (e.g., vacuum pump, syringe) to aspirate fluids. Likewise, hose nib  88  may be used to lavage the tissue cavity with saline, pain medication, or bleeding control fluids.. The proximal port  80  communicates through a proximal vacuum conduit  90  to the interfacing vacuum conduit  16 .  
         [0081]     With further reference to  FIG. 3 , a sample extraction feature is incorporated so that multiple samples may be made without the need to remove the probe assembly  28  from tissue nor even to full retract the cutter tube  40  to retract a tissue specimen to the reusable hand piece  12 . In the illustrative version, this feature is accomplished with a stacking straw assembly  100 . An elongate straw  102  is scored down its length on opposite sides by grooves  104  defining first and second straw halves  106 ,  108 , whose respective proximal, outer surfaces  110 ,  112  are attached to triangular grips  114 ,  116 , respectively. A locking strip  118  extends distally from one triangular grip  114  and is attached along a proximal portion of the first straw half  106 .  
         [0082]     Distal and proximal tabs  120 ,  122  extend from the inner surface  27  of the substantially rectangular cover  22 , each having a respective through hole  124 ,  126  through which the stacking straw assembly  100  is inserted. The through holes  124 ,  126  are shaped to allow the locking strip  118  to rotate ninety (90) degrees. A bayonet locking member  130  also extends from the inner surface  27  of the substantially rectangular cover  22  just distal and laterally offset from the through hole  124  of the distal tab  120  to lock into an alignment locking slot  132  in the locking strip  118  when laterally rotated. The bayonet locking member  130  prevents axial movement of the stacking straw assembly  100 . The cutter gear  44  and cutter tube  40  cannot move proximally due to contact with the stacking straw assembly  100  and cannot move distally due to contact with the probe union sleeve  26 . By securing both the cutter gear  44  and the stacking straw assembly  100  in a full distal axial position, the disposable probe  14  is aligned to engage the components of the reusable hand piece  12  as described below. Distal to the alignment locking slot  132 , a rectangular recess  134 , formed in the locking strip  118 , defines a distal-most locking finger  136  for engaging components of the reusuable hand piece  12  that positions the stacking straw assembly  100  as described below. An indicator tube  150  has a stacked cone-shaped outer surface  152  ( FIG. 14 ) that slides within the elongate straw  104  that in turn slides within the cutter tube  40 .  
         [0083]     With particular reference to  FIG. 4 , the reusable hand piece  12  includes four user controls aligned on a top surface  160  of the housing  20 , specifically from most distal to most proximal: a forward motor rotation key  162 , a reverse motor rotation key  164 , a saline flush key  166  and a slide button  168  for selecting insertion mode or sample taking mode. The keys  162 - 166  control a control circuit  170 , which may include integral power storage (e.g., batteries, fuel cell, etc.) for untethered use. The forward motor rotation key  162  causes a DC motor  172  to rotate its motor output shaft  174  in a forward rotation. A slide spur gear  176  includes an internal keyed engagement with a longitudinal key groove  178  on the motor output shaft  174  that allows longitudinal positioning by the slide button  168 . In particular, fore and aft brackets  180 ,  182  of the slide button  168  engage distal and aft annular grooves  184 ,  186  that flank spur gear teeth  188  of the slide spur gear  176 .  
         [0084]     When the slide button  168  is moved distally, the slide spur gear  176  engages a tissue penetration gear  190  that spins on a common shaft centerline  192  forward of a gearbox input gear  196 . Gearbox input gear  196  consists of a distal small gear  198  and a proximal large gear  200 . The tissue penetration gear  190  has spur gear teeth  206  that engage the slide spur gear  176 . A frame hub  212  projects proximally from the frame  204  with a strike pin  214  projecting upwardly from the frame hub  212 . In  FIG. 4  and  13 , a circular cam wheel  216  is attached to a distal side of the tissue penetration gear  190 . Rotating the tissue penetration gear  190  urges the strike pin  214 , and thus the frame  204 , proximally. In  FIG. 12 , left and right spring cavities  218 ,  220  (when viewed from above), formed longitudinally in distal comers of the frame  204 , respectively receive inwardly projecting left and right tabs  222 ,  224  from the cover  20  and receive left and right compression springs  226 ,  228 . Movement of the frame  204  proximally compresses these compression springs  226 ,  228  that thereafter assert a restoring force.  
         [0085]     When the slide button  168  is moved proximally into engagement with the gearbox input gear  196 , specifically the distal small gear  198 , also engages and turns a translation large input gear  230  whose shaft  232  passes through an aft wall  234  of the frame  204 . The proximal large gear  200  of the gearbox input gear  196  engages and turns a rotation small input gear  236  whose shaft  238  passes through the aft wall  234 . The frame  204  includes a carriage recess  240 , defined between a partition  242  and the aft wall  234 , that contains longitudinally aligned left side lead (translation) screw  244  and right-side rotation spur gear  246  that are attached for rotation respectively with the shafts  232 ,  238 . The partition  242  is positioned aft of the left and right tabs  222 ,  224  of the cover  20  and also defines in part the left and right spring cavities  218 ,  220 . An unlocking cam  247  projects proximally from and is longitudinally centered on the aft wall  234  above the position of the lead (translation) screw  244  and rotation spur gear  246 .  
         [0086]     The rotation spur gear  246  engages the cutter gear  44  when the disposable probe  14  is inserted, imparting a rotation as the cutter tube  40  and cutter gear  44  translate longitudinally in response to the rotation of the lead (translation) screw  244 . This translation is caused by lead screw threads  248 . In particular, a distal cutter carriage  250  is longitudinally moved on the lead screw threads  248 . Distal and proximal J-hook extensions  252 ,  254  project downwardly from the distal cutter carriage  250  to engage the distal and proximal annular recesses  54 ,  56  of the cutter gear  44  ( FIG. 3 ). Distal of the cutter carriage  250 , a biasing spring  256  urges against the cutter carriage  250 , which assists in engagement of the lead screw threads  248  with the distal cutter carriage  250 . With reference to  FIGS. 4 and 19 , a sliding pin  260  has a proximal carriage sliding pin retainer  266  attached to a proximal straw carriage  258 . Shaft  264  also passes through a distal carriage sliding pin retainer  270  attached to the distal cutter carriage  250 . Sliding pin  260  has a proximal end  262  and a distal end  268  to prevent the sliding pin  260  from disengaging from the carriage sliding pin retainers  266 ,  270 . A sliding pin spring  272  resides on the sliding pin  260  and is constrained at each end by carriage sliding pin retainers  266 ,  270 .  
         [0087]     With the components  FIGS. 1-4  now introduced, a sequence of use of the biopsy device  10  will be described. The interfacing vacuum lumen  16  is attached to the disposable probe assembly  14  ( FIGS. 1-2 ). The disposable probe assembly  14  is installed into the reusable hand piece  12  ( FIGS. 5-8 ). In so doing, the distal cutter carriage  250  engages the cutter gear  44  ( FIG. 9 ), the proximal straw carriage  258  engages the locking strip  118  of the stacking straw assembly  100  ( FIG. 10 ), and the bayonet locking member  130  is deflected by the unlocking cam  247 , longitudinally unlocking from the alignment locking slot  132  of the locking strip  118  ( FIG. 11 ) allowing longitudinal movement of the cutter tube  40  and the straw stacking assembly  100 .  
         [0088]     In  FIGS. 12, 14 , the cutter and straw carriages  250 ,  258  may initially be distally advanced to close the side aperture  34  of its probe tube  30  with the cutter tube  40  and the stacking straw assembly  100  also fully distally advanced to minimize proximal extension of its elongate straw  102 .  
         [0089]     In  FIG. 13 , the piercing tip  38  of the core biopsy needle (probe) assembly  28  is assisted in penetrating tissue by moving the slide button  168  distally to a “tissue insertion mode” wherein the slide spur gear  176  engages the tissue penetration gear  190 . depression of the forward motor rotation key  162  turns these gears  176 ,  190  causing the circular cam wheel  216  to turn against strike pin  214  that creates proximal longitudinal motion of frame  204  and core biopsy needle (probe) assembly  28  of approximately 0.1 inch at a rotation rate of 7 cycles per second. Left and right compression springs  226 ,  228  provide the restoring distal longitudinal motion to frame  204  and disposable probe  14  as left and right compression springs  226 ,  228  are repeatedly compressed between the forward surface of the left and right spring cavities  218 ,  220  as the frame  204  and the left and right tabs  222 ,  224  of the housing  20 . The restoring distal longitudinal motion to frame  204  and core biopsy needle (probe) assembly  28  result in a corresponding distal motion of piecing tip  38  that assists in penetrating tissue.  
         [0090]     In  FIG. 15 , with the side aperture  40  positioned within the tissue to take samples, the slide button  168  is moved proximally to engage the slide spur gear  176  with the distal small gear  198  of the gearbox input gear  196 . When the forward motor rotation key  162  is depressed, the DC motor  172  rotates in a forward direction, turning the slide spur gear  176 , which turns the distal small gear  198  that directly turns the translation large input gear  230  that is connected by the shaft  232  through the aft wall  234  of the frame  204  to the lead (translation ) screw  244 . Meanwhile, the proximal large gear  200  of the gearbox input gear  196  rotates the small input gear  236  that turns shaft  238  through aft wall  234  to turn the rotation spur gear  246 .  
         [0091]     With the carriages  250 ,  258  distally advanced as depicted in  FIGS. 15-16 , the cylindrical proximal portion  70  of the vacuum valve actuator  68  is also distally positioned as depicted in  FIG. 17 . The hose nib  88  is thus in fluid communication through the distal port  84 , through the distally open cylindrical valve bore  76  between distal and proximal dynamic O-ring seals  74 ,  75  to the center port  82  through the distal vacuum conduit  86  to the vacuum lumen  32 .  
         [0092]     In  FIGS. 18-19 , depression of the reverse motor rotation key  164  causes the lead (translation) screw  244  to rotate in a reverse direction. Sliding pin spring  272  between the distal cutter carriage  250  and the proximal straw carriage  258  urges the proximal straw carriage  258  into engagement with the lead screw thread  248 , causing the straw carriage  258  to move proximally as the cutter carriage  250  free wheels on an unthreaded distal portion of the lead screw  244 . The straw carriage  258  draws back the elongate straw  102  and the indicator tube  150  ( FIG. 20 ). As the straw carriage  258  approaches the proximal portion of the lead screw  244 , the distal end  268  of sliding pin  260  contacts the distal carriage sliding pin retainer  270  on distal cutter carriage  250 , pulling the distal cutter carriage  250  onto the lead screw thread  248 . Thereafter, the cutter carriage  250  and the cutter tube  40  are retracted as the straw carriage  258  free wheels ( FIGS. 21-22 ).  
         [0093]     Alternately, sliding pin spring  272  may be replaced with a ball detent mechanism (not shown) located on frame  204  that would engage with a small depression in proximal straw carriage  258 . This alternate mechanism in conjunction with biasing spring  256  would cause both the distal cutter carriage  250  and proximal straw carriage  258  to retract simultaneously from their fully distal position and to advance sequentially from their fully proximal position (i.e., cutter carriage  250  would fully advance and then the straw carriage  258  would advance).  
         [0094]     At the end of the proximal movement of the cutter tube  40 , vacuum valve actuator  68  is moved proximally such that the distal and proximal dynamic O-ring seals  74 ,  75  bracket the proximal port  80  and center port  82  of the distally open cylindrical valve bore  76 . Thereby, the interfacing vacuum conduit  16  draws air through the proximal vacuum conduit  90 , through the valve body  78 , through the distal vacuum conduit  86 , and ultimately from the vacuum lumen  32  ( FIG. 24 ). In  FIG. 23 , this suction draws tissue  280  into the side aperture  34  of the probe assembly  28 .  
         [0095]     It should be appreciated that in the illustrative version, the distal cutter carriage  250  does not freewheel ( FIG. 21 ) in its proximal-most position. Instead, rotation of the motor is stopped as the distal cutter carriage  250  is about to contact the proximal straw carriage  258  with closed-loop control based on an encoder (not shown) coupled to the DC motor  172  enabling accurate positioning of the motor output shaft  174 . Alternatively, freewheeling may be incorporated at the proximal-most position of the distal cutter carriage  250  by adding a section of no helical threads to the proximal end of the lead (translation) screw  244  equal to the longitudinal thickness of the distal cutter carriage  250 .  
         [0096]     It should further be appreciated that free wheeling may be provided for cutter translation even without stacking straw sample retraction to avoid reliance upon other structures to block further translation or more elaborate closed loop position control.  
         [0097]     The forward motor rotation key  162  is depressed to advance the cutter tube  40 , rotating lead (translation) screw  244  and rotation spur gear  246 , as depicted in  FIG. 25 . Due to sliding pin spring  272  between carriages  250 ,  258 , only the distal cutter carriage  250  engages with the lead screw threads  248  of the lead (translation) screw  244  and translates distally initially cutting tissue  280 , as depicted in  FIG. 26 . Once the distal cutter carriage  250  approaches its distal-most position, the sliding pin  260  pulls the proximal straw carriage  258  into engagement with the lead screw threads  248  of the lead (translation) screw  244 . As the cutter carriage  250  freewheels, the elongate straw  102  is distally translated to encompass a first severed tissue sample  280   a , displacing proximally the indicator tube  150  a corresponding amount.  
         [0098]     At this point, depression of the reverse motor rotation key  164  causes retraction of the proximal straw carriage  258  ( FIG. 18 ) with the side aperture  134  communicating with atmospheric pressure ( FIG. 17 ) as previously discussed so that the first severed tissue sample  280   a  remains within the elongate straw  280   a . It should be appreciated that repeating the retraction and advancement of the cutter carriage  250  thereafter results in a second severed tissue sample  280   b  being encompassed by the elongate straw  102  and the indicator tube  150  being further proximally displaced thereby as depicted in  FIG. 27 . An additional retention feature is depicted in  FIG. 27  wherein small bent-up, proximally directed tabs  284  formed in the elongate straw  102  resist distal movement of the severed tissue samples  280   a ,  280   b . This automated sequencing of the cutter and straw carriages  250 ,  258  during retraction and advancement may be repeated a number of times to take a plurality of samples without withdrawing the probe assembly  28  from tissue  280 . The surfaces of the elongate straw  102  may be coated with lubricous materials to aid in proximal movement of tissue through the elongate straw  102  and to reduce friction between the elongate straw  102  and the cutter tube  40 . Likewise, to aid in proximal movement of tissue through the elongate straw  102 , the diameter of the elongate straw  102  and the cutter tube  40  may be increased slightly some distance proximal from their distal end to reduce the friction of the tissue through the elongate straw  102 .  
         [0099]     In  FIG. 28 , a proximal end of the stacking straw assembly  100  includes a one-way latch (mechanical diode)  290  that engages the stacked cone shaped outer surface  152  of the indicator tube  150  as it proximally extends out of the elongate straw  102  preventing its being pneumatically drawn back into the elongate straw  102  when subsequently exposed to vacuum pressure.  
         [0100]     In  FIGS. 29, 30 , the proximal straw carriage  258  is shown to include distal and proximal J-hooks  300 ,  302  that encompass on three sides the stacking straw assembly  100 . In particular, the rectangular recess  134  formed in the locking strip  118  is sized to longitudinally bracket the J-hooks  300 ,  302  with the distal locking finger  136  preventing retraction as depicted in  FIG. 29  when the triangular grips  114 ,  116  are positioned horizontally ( FIG. 31 ), as would be typical before and during use of the biopsy device  10 . The surgeon may wish to segregate samples as they are taken or to take more samples than possible within one stacking straw assembly  100 . Extraction and replacement of the stacking straw assembly  100  is allowed by rotating the triangular grips one quarter turn counterclockwise (as viewed proximally) as depicted in  FIG. 32 , which rotates the locking finger  136  out of alignment with the J-hooks  300 ,  302  of the straw carriage  258  ( FIG. 30 ). A new stacking straw assembly  100  is then reinserted in reverse fashion.  
         [0101]     In  FIG. 33 , samples contained in the removed stacking straw assembly  100  may be accessed by pulling apart the triangular grips  114 ,  116  causing the grooves  104  to peel apart the first and second straw halves  106 ,  108 , which need not be symmetric. The samples may be removed individually or the samples and the straw half  106  portion of the straw  102  in which they are located may be put directly into a formalin solution for pathological preparation. Alternately, the samples contained in the stacking straw assembly  100  can be removed from the elongate straw  102  with a simple plunger-like rod (not shown) eliminating the need to peel apart the straw to access the tissue samples.  
         [0102]     Although the integral vacuum assistance supported by a medical vacuum pump may often be advantageous, some surgeons may desire to palpitate tissue into a side aperture of a probe assembly without the assistance of vacuum. To that end, in  FIGS. 34-36 , an alternative disposable probe  414  is depicted that omits a vacuum valve capability that responds to the cutter position but is otherwise identical to the afore-described disposable probe  14 . The modified components of the disposable probe assembly  414  include a substantially rectangular cover  422  sized to close the access trough recess  18  of the reusable hand piece  12  (not shown in  FIGS. 34-36 ). The probe union sleeve  26 , attached to the inner surface  27  of the substantially rectangular cover  422 , communicates through a short pneumatic conduit  425  that terminates on the outer surface  79  at a hose nib  427 . Hose nib  427  may include an air and/or saline filter. Alternatively, hose nib  427  may be connected to a positive pressure source (e.g. fluid pump) or a negative pressure source (e.g., vacuum pump, syringe) to aspirate fluids. Hose nib  427  could also be used to lavage the tissue cavity with saline, pain medication, or bleeding control fluids. A core biopsy needle (“probe”) assembly  428  that passes longitudinally through the probe union sleeve  26  differs in that a cutter gear  444  needs only engage and respond to the distal cutter carriage  250  (not shown in  FIGS. 34-36 ) and not also position a pneumatic valve. Cutter guide tab  445  extends out from the inner surface  27  to provide a distal stop for cutter gear  444 . Prior to insertion of the disposable probe  414  into the reusable hand piece  12  (not shown in  FIGS. 34-36 ), the bayonet locking member  430  prevents axial movement of the stacking straw assembly  100 . The cutter gear  444  and cutter tube  40  cannot move proximally due to contact with the stacking straw assembly  100  and cannot move distally due to contact with the cutter guide tab  445 . By securing both the cutter and straw in a fully distal axial position, it insures that when the disposable probe  414  is inserted into the reusable hand piece  12  that the cutter gear  444  and stacking straw assembly  100  align and engage with the correct components within the reusable hand piece  12 .  
         [0103]     In  FIG. 37 , an alternative disposable assembly  514  is, as described in  FIG. 3  but with the stacking straw assembly  100 , replaced with a straw assembly  516  having distal tube  518  attached to a proximally attached luer fitting  520 . The straw assembly  516  may be used to flush the cavity (via side aperture  34 ) with saline, epinephrine (or similar substances that reduce bleeding), or lidocane (or similar substances that reduce pain) by attaching a syringe or similar device (not shown) to the luer fitting  520 . To remove the saline, epinephrine, or lidocane from the tissue, the cutter tube  40  may be fully or partially retracted to insure that the valve assist valve assembly  52  is positioned to connect the lateral lumen (distal vacuum conduit  86 ) with the vacuum source ( and not simply atmospheric pressure) as depicted in  FIG. 24 . The fluid would then be drawn from the tissue cavity (via side aperture  34 ), through the lateral lumen (distal vacuum conduit  86 ) and into a canister located in line with the vacuum source (not shown).  
         [0104]     In  FIG. 38 , an alternative biopsy needle (probe) assembly  628  is identical to that depicted in  FIG. 14  with the exception of a probe tube  630  with through holes  631  placed proximate to the side aperture  34 . The vacuum lumen  32  thus communicates with the holes  631  in the probe tube  630  as an alternate means to apply saline, epinephrine, or lidocane to the tissue cavity. These through holes  631  allow the fluid to reach the cavity while the elongate straw  102  and indicator tube  150  remain distally positioned in the cutter tube  40  (i.e., during the middle of a biopsy sampling procedure). In this case, the syringe would be attached to the hose nib  88  via a stopcock fitting (not shown). With the stopcock valve positioned to connect the syringe directly to the needle&#39;s lateral lumen (distal vacuum conduit  86 ), when the syringe is depressed the fluid will enter the lateral lumen (distal vacuum conduit  86 ) and then flow into the tissue through the through holes  631  in the wall of the probe tube  630 . The cutter tube  40  would be positioned distally (side aperture  34  closed) while the fluid is being inserted into the cavity to prevent the tissue indicator tube  150  from being moved proximally due to the fluid pressure. During subsequent sampling cycles, the fluid would then be aspirated from the tissue cavity.  
         [0105]     In  FIGS. 39-45 , an alternative proximal stacking disposable assembly  702  is depicted that may also be used with the reusable hand piece  12 . Pneumatic force is employed to retrieve tissue samples rather than a mechanical movement from the reusable hand piece  12  that actuates a straw assembly. To that end, in  FIG. 39 , a core biopsy needle (“probe”) assembly  704  is formed by a probe tube  706  with a distally positioned side aperture  708 . A cutter tube  710  is sized to closely fit and translate within an inner diameter (i.e., cutter lumen)  712  of the probe tube  706  with a length sufficient to close the side aperture  708 . The probe assembly  704  includes an underlying vacuum lumen  714  that communicates with the cutter lumen  712  via through holes  716  underlying the side aperture  708 . Both the probe tube  706  and vacuum lumen  714  distally terminate in open ends that communicate with each other via a curved manifold  718  defined inside of a piercing tip  720  that is attached as a distal-most portion of the probe assembly  704 . A distal tissue stop  722  projects from the piercing tip  720  into the distal open end of the probe tube  706  to maintain prolapsed tissue inside a sampling bowl  724  under the side aperture  708  within the cutter lumen  712 . Prolapsing occurs under the urging of axial vacuum force through the cutter lumen  712  and lateral vacuum force through the vacuum lumen  714  converging at the side aperture  708 . After distal translation of the rotated cutter tube  712 , a tissue sample  726  resides within a distal portion of the cutter tube  712 , wherein an inner diameter of the cutter tube  712  defines a tissue sample lumen  728  for guiding retrieval of samples  726 . Rather than subsequently distally advancing a straw to encompass and retract the tissue sample  726 , axial vacuum pressure as depicted by arrow  730  is asserted against a proximal face of the tissue sample  726  through the tissue sample lumen  728  with the cooperation of lateral pneumatic pressure as depicted by arrow  732  through vacuum lumen  14  and curved manifold  718  to a distal face of the tissue sample  726 .  
         [0106]     In  FIGS. 40-45 , the portions of the alternative proximal stacking disposable assembly  702  capture these tissue samples  726 . A proximal end of the cutter tube  710  extends through a probe union sleeve  734  to attach to a cutter gear  736 . A proximal end of the vacuum lumen  714  terminates within the probe union sleeve  734 . The alternative proximal stacking disposable assembly  702  includes a substantially rectangular cover  738  sized to close the access trough recess  18  ( FIGS. 2, 4 ), and omits pneumatic valve features. Instead, the distally positioned probe union sleeve  734  attached to an inner surface  740  of the substantially rectangular cover  738  communicates to a distal hose nib  742  formed on an outer surface  744  of the rectangular cover  738  and to the vacuum lumen  714 . A hose  746  is attached to the distal hose nib  742  to selectively provide pneumatic vacuum, pneumatic pressure, or fluid transfer (not shown). The alternate proximal stacking assembly  702  could likewise have a vacuum assist valve assembly  052  as depicted in  FIG. 2  to selectively provide pneumatic vacuum, pneumatic pressure, or fluid transfer to the vacuum lumen  714 .  
         [0107]     With particular reference to  FIGS. 40, 42 , a rear tube  748  is aligned proximally to the cutter tube  710  and coupled for longitudinal movement thereto, although the rear tube  748  is disengaged from the rotational movement of the cutter tube  710 . This coupled movement may be achieved by an actuator that engages the distal cutter carriage  250  ( FIG. 4 ) or by a circular lip and groove engagement between the cutter tube  710  and rear tube  748 . The inner surface  740  of the rectangular cover  738  includes four support surfaces. First, a cutter guide  750  supports the cutter tube  710  proximal to the probe union sleeve  734  and distal to a most distal position of the cutter gear  736 . A distal rear tube guide  752 , is proximal to the most proximal position of the cutter gear  736 , and a proximal rear tube guide  754 , and distal to a most distal position of a proximal locking flange  756  of the rear tube  748 , to maintain alignment of the rear tube  748 . A bottom half-cylinder locking flange  758  at a proximal end of the rectangular cover  738  cooperates with the proximal locking flange  756  of the rear tube  748  to lock to a sample holding portion  760  of the alternative proximal stacking disposable assembly  702 . The sample holding portion  760  extends proximal to the rectangular cover  738  and the reusable hand piece  712  and thus may be readily replaced during a biopsy procedure.  
         [0108]     A distal locking half cylindrical portion  762  engages the bottom half-cylinder locking flange  758 . The distal locking half cylindrical portion  762  is attached to a proximal half cylindrical portion  764  to form an outer sleeve  766 . A reciprocating member  768 , which engages the proximal locking flange  756  of the rear tube  748  and is partially encompassed by the outer sleeve  766 , engages and distally advances a more proximal rod  770  out of an external vacuum lumen  772  defined as an inner diameter of an external vacuum tube  773 . The rod has a down turned distal end  774  that exits an opening  776  in the proximal half cylindrical portion  764 . A flexible, peel-apart external tissue tube  777  defining an external tissue lumen  778  is formed from an inwardly open channel  780  closed by an elongate seal  782 .  
         [0109]     Rod  770  may be formed of a fluoropolymer resin material such as TEFLON™ or other suitable flexible material having a low coefficient of friction. Rod  770  may be sized and shaped to conform closely to the inner diameter (i.e., vacuum lumen  772 ) of vacuum tube  773 . The close fit between rod  770  and vacuum lumen  773 , as well as the low friction properties of the rod  770 , enable the rod  770  to translate easily within the vacuum lumen  772  without any loss of vacuum force through the distal end of the vacuum lumen  772 . The inwardly open channel  780  may advantageously be formed of polyvinyl chloride or another similar type of flexible, water insoluble material so that stacked tissue samples may be visible. A proximal end of the open channel  780  is attached to and closed by a lumen peel tab  784 . A proximal end of the external vacuum lumen  772  is attached to a vacuum line  786  via a tubing connector  788 .  
         [0110]     In  FIGS. 40, 41 , the alternative proximal stacking disposable assembly  702  is in an initial condition with the rod  770  at its proximal most position in the external vacuum lumen  772 . The cutter gear  736  and thus the rear tube  748 , reciprocating member  768  and flexible, peel-apart external tissue lumen  778  are in their distal most position. In  FIGS. 43, 44 , the rod  770  has extruded distally out of the opening  776  in the proximal half cylindrical portion  764  of the outer sleeve  766 , denoting reciprocating cycles to retract at least one tissue sample (not shown) that is held within a proximal portion of the external tissue lumen  778 . The cutter gear  736  and thus the rear tube  748 , reciprocating member  768  and flexible, peel-apart external tissue lumen  778  are in their proximal most positions relative to the outer sleeve  766  and rectangular cover  738 . The relative change causes the flexible, peel-apart external tissue lumen  778  to bow away from the outer sleeve  766 . In  FIG. 45 , the lumen peel tab  784  has been pulled to separate the inwardly open channel  780  from the elongate seal  782  to reveal and possibly access stored tissue samples (not shown).  
         [0111]     In  FIGS. 46-48 , the sample holding portion  760  is depicted in greater detail. The distal locking half cylindrical portion  762  of the outer sleeve  766  includes upper lateral locking arms  790  that lock into the bottom half-cylinder locking flange  758  at the proximal end of the rectangular cover  738 . In  FIGS. 46, 47 , aligned below these, lower lateral locking arms  792  of a distal interface portion  794  of the reciprocating member  768  lock into the proximal locking flange  756  of the rear tube  748 . The distal interface portion  794  of the reciprocating member  768  includes an axially-extending bore  796  for connecting the external tissue lumen  778  of the sample holding portion  760  to the rear tube  748 , maintaining generally coaxial alignment of the probe assembly  702 , tissue sample lumen  728 , rear tube  748 , bore  796 , and external tissue lumen  778  to provide an unobstructed passageway for the aspiration of tissue samples from the cutter tube  710 .  
         [0112]     In FIGS.  48 ,  50 - 51 , the flexible rod  770  may be advanced distally within the external vacuum lumen  772  by the interaction between side ratchet teeth  798  and a pawl-type latching mechanism  800  on the reciprocating member  768 , which is shown in greater detail in  FIG. 49 . Reciprocating member  768  may be supported on lower lateral latch arms  792  and reciprocate as cutter tube  710  is advanced and retracted. Reciprocating member  768  may have a bifurcated proximal end with proximally extending portions  802  separated by an axially extending slot  804 . A ramped surface  806  is formed between portions  802  at a distal end of slot  804 . Ramped surface  806  may serve to deflect the distal end  774  of rod  770  through the opening  776  in the outer sleeve  766  as the rod  770  is ratcheted out of external vacuum lumen  772 . Unidirectional engagement pawls  808  formed to inwardly extend from the proximally extending portions  802  into the axially extending slot  804  engage side ratchet teeth  798  on rod  770  as the rod  770  extends through the axially extending slot  804 . The engagement between pawls  808  and side ratchet teeth  798  advances rod  770  distally through vacuum lumen  772 .  
         [0113]     In  FIG. 51 , a plurality of small holes  810  may be formed in a center wall divider  812  of the external vacuum tube  773  between external vacuum lumen  772  and tissue lumen  778 . Small holes  810  enable vacuum from a source (not shown) connected to vacuum line  786  to communicate from external vacuum lumen  772  into external tissue lumen  778 , to provide vacuum in tissue sample lumen  728  in cutter tube  710 . Small holes  810  may be spaced along the longitudinal axis of tube vacuum tube  773  and separated by a distance in the range of 0.1 to 4 centimeters. Holes  810  may be oriented at an angle relative to the longitudinal axis of vacuum tube  773 . The angle in holes  810  may function as a mechanical diode, in that the edge of the holes  810  opening into the tissue lumen  778  may aid in preventing motion of tissue samples  726  in a distal direction, while permitting tissue samples  726  to move proximally in tissue lumen  778  under vacuum force provided by the vacuum line  786 . A tissue sample  726  may continue to slide proximally through the tissue lumen  778  until the sample  726  contacts either a proximal tissue stop  812  attached to the lumen peel tab  784  or a preceding tissue sample  726 .  
         [0114]     With further reference to  FIG. 51 , small holes  810  may be formed between lumens  772 ,  778  by boring top holes  813  into an upper surface  814  of external vacuum tube  773  with the sharpened tip of a drill or other appropriate instrument. The tip of the drill bit or other boring instrument may be directed to pass through vacuum lumen  772  to penetrate the center wall divider  812  that separates the two lumens  772 ,  778 .The proximal half cylindrical portion  764  of the outer sleeve  766  may be securely attached to the upper surface  814  of the external vacuum tube  773  following the drilling of vacuum communication small holes  810  to seal top holes  813 . For instance, outer sleeve  766  may be attached to the external vacuum tube  773  by an adhesive or other appropriate type of attachment mechanism.  
         [0115]     As tissue samples  726  are stored in tissue lumen  778 , the stack of samples  726  will grow in length distally in tissue lumen  778 . The samples  726  will tend to block or otherwise restrict flow communication through small holes  810  as the stack of samples  726  extends distally in tissue lumen  778 . The translating flexible rod  770  is shown disposed at least partially in vacuum lumen  772 . Rod  770  extends axially through vacuum lumen  772  to selectively cover or otherwise block at least some of the small holes  810 . Rod  770  may be manipulated, such as by axial movement of rod  770 , to selectively expose small holes  810  in the vacuum tube  773  in compensation for those holes  810  blocked by stacked tissue samples  726 . For instance, during each cutting cycle, rod  770  may be advanced distally within vacuum lumen  772  to expose or otherwise unblock/open additional small holes  810  as additional samples  726  are stored in tissue lumen  778 . The movement of rod  770  maintains a predetermined number of small holes  810  open to provide flow communication between vacuum and tissue lumens  772  and  778  as additional tissue samples  726  are added to the stack of tissue samples  726  in tissue lumen  778 , thereby facilitating a generally consistent vacuum force, depicted as arrow  816 , in tissue sample lumen  728  in the probe assembly  704  ( FIG. 39 ) throughout multiple cutting cycles.  
         [0116]     Initially as depicted in  FIG. 52 , flexible rod  770  may be inserted within vacuum lumen  772  such that rod  770  is axially offset within vacuum lumen  772  so as to cover or otherwise block most, but not all, of the small holes  810 . For instance, prior to storing any samples  726  in tissue lumen  778 , rod  770  may be offset distally within vacuum lumen  772  a distance that is slightly longer than the length of side aperture  708  ( FIG. 40 ). Offsetting rod  770  distally within the vacuum lumen  772  ensures an initial set of small holes  810  are exposed to communicate axial vacuum force  730  to side aperture  708  when cutter tube  710  is in the fully proximal position prior to tissue sampling. The axial vacuum force  730  communicated through the exposed small holes  810  aids in prolapsing tissue into side aperture  708  prior to cutting, as well as pulling the tissue sample  726  proximally into tissue lumen  778  after cutting. As a tissue sample  726  is drawn into and stacked within tissue lumen  778 , the tissue sample  726  blocks the previously exposed small holes  810 , preventing vacuum from passing into the tissue lumen  778 . Rod  770  may be selectively moved a predetermined distance distally that is slightly longer than the length of side aperture  708  to expose additional small holes  810  immediately distal of the most recently acquired tissue sample  726 . Rod  770  may be adapted to be automatically advanced distally by the translation of the cutter carriage  250 . The newly exposed small holes  810  continue the communication of vacuum force  816  into tissue lumen  778  for the next cutting cycle. As reciprocating member  768  retracts proximally, unidirectional bottom ratchet teeth  818  located on the bottom side of flexible rod  770  engage the small holes  810  within vacuum lumen  772 . The engagement between the bottom ratchet teeth  818  and small holes  810  prevents rod  770  from moving proximally within vacuum lumen  772 . As pawls  808  move proximally relative to rod  770 , the pawls  808  engage the next proximal set of side ratchet teeth  798  on rod  770 . This engagement with the next set of side ratchet teeth  798  causes rod  770  to again advance distally when the reciprocating member  768  advances distally during the next cutting cycle to expose additional small holes  810 . In the event that the cutter tube  710 , and thus the reciprocating member  768 , is advanced and retracted without the probe assembly  704  in tissue, the result is that the flexible rod  770  advances too far distally relative to the tissue samples  726 ; the flexible rod  770  may be rotated a fraction of a turn about its longitudinal axis to disengage side ratchet teeth  798  and pawls  808  allowing the flexible rod  770  to be repositioned proximally within the vacuum lumen  772 .  
         [0117]     A similar sample holding portion is described in five commonly-owned and co-pending U.S. patent application Ser. No. 10/953834, “Biopsy Apparatus and Method” END-5469; Ser. No. 10/953,904 “Improved Biopsy Apparatus and Method” END 5470; Ser. No. 10/953,397 “Fluid Control for Biopsy Device” END 5471; Ser. No. 10/953,395 “Biopsy Device with Sample Storage” END 5472; and Ser. No. 10/953,389 “Cutter for Biopsy Device” END 5473, all to Hibner et al. and filed on 29 Sep. 2004, the disclosures of which are hereby incorporated by reference in their entirety.  
         [0118]     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 spirit and scope of the appended claims. Additionally, each element described in relation to the invention may be alternatively described as a means for performing that element&#39;s function.  
         [0119]     For example, one or more sensors may be incorporated into the hand piece  12  to sense the actual position of each carriage or to sense the particular disposable probe assembly assembled into the hand piece  12 .