Biopsy apparatus

Abstract

A disposable tissue removal device comprises a “tube within a tube” cutting element mounted to a handpiece. The inner cannula of the cutting element defines an inner lumen and terminates in an inwardly beveled, razor-sharp cutting edge. The inner cannula is driven by both a pneumatic rotary motor and a pneumatic reciprocating motor. At the end of its stroke, the inner cannula makes contact with the cutting board to completely sever the tissue. An aspiration vacuum is applied to the inner lumen to aspirate excised tissue through the inner cannula and into a collection trap removably mounted to the handpiece. The rotary and reciprocating motors are hydraulically or pneumatically powered through a foot pedal operated pneumatically circuit. In one embodiment, the cutting element includes a cannula hub that can be connected to a fluid source, such as a valve-controlled saline bag.

1 . A tissue cutting device comprising: 
 an outer cannula defining an outer lumen and a tissue-receiving opening adjacent a distal end of said outer cannula communicating with said outer lumen;    an inner cannula slidably disposed within said outer lumen and defining a inner lumen from an open distal end to an open opposite proximal end, said inner cannula defining a cutting edge at said open distal end operable to sever tissue projecting through said tissue receiving opening;    a first hydraulic rotary motor operably coupled to said inner cannula to rotate said inner cannula within said outer cannula;    a second hydraulic reciprocating motor operably coupled to said inner cannula to translate said inner cannula within said outer cannula while said inner cannula rotates; and    a hydraulic system connecting said first and second hydraulic motors to a source of pressurized fluid.    
   
   
       2 . The tissue cutting device of  claim 1  further comprising a cutting board disposed at said distal end of said outer cannula.  
   
   
       3 . The tissue cutting device of  claim 2  wherein said cutting board is formed of a resilient plastic material having a hardness less than a hardness of said inner cannula at said cutting edge, but sufficient to substantially prevent permanent deformation of said cutting board under pressure from said cutting edge as said inner cannula rotates and reciprocates against said cutting board.  
   
   
       4 . The tissue cutting device of  claim 1  wherein said cutting edge is an inwardly beveled surface.  
   
   
       5 . The tissue cutting device of  claim 4  further comprising a dimple in an inner surface of said outer cannula immediately proximal to said tissue-receiving opening, said dimple sized to fit between said inner cannula and said outer cannula.  
   
   
       6 . The tissue cutting device of  claim 1  further comprising a handpiece removably engageable to said outer cannula and supporting said inner cannula, said first hydraulic rotary motor, and said second hydraulic reciprocating motor.  
   
   
       7 . The tissue cutting device of  claim 6  further comprising a collection trap removably mountable to said handpiece and in communication with said proximal end of said inner lumen.  
   
   
       8 . The tissue cutting device of  claim 7  wherein said collection trap includes a filter element disposed within said collection trap.  
   
   
       9 . The tissue cutting device of  claim 7  further comprising a vacuum source in fluid communication with said collection trap to aspirate tissue through said inner lumen into said collection trap.  
   
   
       10 . The tissue cutting device of  claim 6  further comprising a cover removably engageable to and enclosing said handpiece.  
   
   
       11 . The tissue cutting device of  claim 10  wherein said cover includes: 
 at least one tang projecting inwardly from an inner surface thereof; and    said handpiece defines at least one engagement notch configured for receiving a corresponding one of said at least one tang for engaging said cover to said handpiece.    
   
   
       12 . The tissue cutting device of  claim 1  wherein said outer cannula further includes a stiffening element along a length thereof for increasing a bending resistance of said outer cannula.  
   
   
       13 . The tissue cutting device of  claim 12  wherein said stiffening element includes a longitudinally extending rib defined in an outer surface of said outer cannula.  
   
   
       14 . The tissue cutting device of  claim 13  wherein said rib includes a bead adhered to a surface of said outer cannula.  
   
   
       15 . The tissue cutting device of  claim 13  wherein said rib includes a crimp in said outer cannula.  
   
   
       16 . The tissue cutting device of  claim 12  wherein said stiffening element is substantially diametrically opposite the tissue-receiving opening.  
   
   
       17 . The tissue cutting device of  claim 12  wherein said stiffening element includes a layer of rigid material bonded to a surface of said outer cannula.  
   
   
       18 . The tissue cutting device of  claim 17  wherein said material is stainless steel.  
   
   
       19 . The tissue cutting device of  claim 1  further comprising a vacuum source in fluid communication with said inner lumen at said proximal end of said inner cannula to aspirate tissue through said inner lumen.  
   
   
       20 . The tissue cutting device of  claim 1  further comprising: 
 an irrigation lumen in fluid communication with said outer lumen; and    a source of irrigation fluid in communication with said irrigation lumen.    
   
   
       21 . The tissue cutting device of  claim 20  wherein said source of fluid includes an anesthetic fluid.  
   
   
       22 . The tissue cutting device of  claim 1  further comprising a dimple in an inner surface of said outer cannula immediately proximal to said tissue-receiving opening, said dimple sized to fit between said inner cannula and said outer cannula.  
   
   
       23 . The tissue cutting device of  claim 1  wherein said tissue-receiving opening includes a pair of opposite sides extending longitudinally along said outer cannula, at least one of said opposite sides defining at least one tooth arranged to engage tissue drawn into said opening when said cannula is inserted into a body.  
   
   
       24 . The tissue cutting device of  claim 23  wherein at least one of said opposite sides defines a plurality of teeth, said teeth angled proximally away from said distal end of said outer cannula.  
   
   
       25 . The tissue cutting device of  claim 23  wherein each of said opposite sides defines a plurality of teeth, said teeth angle proximally away from said distal end of said outer cannula.  
   
   
       26 . The tissue cutting device of  claim 1  further comprising a trocar tip having an engagement hub configured to fit tightly within said distal end of said outer cannula.  
   
   
       27 . The tissue cutting device of  claim 26  further comprising a cutting board disposed within said outer lumen affixed to said engagement hub.  
   
   
       28 . The tissue cutting device of  claim 1  further comprising: 
 a tubular axle having a distal end and a proximal end; and    a coupler connecting said distal end of said tubular axle to said proximal end of said inner cannula,    wherein said first hydraulic rotary motor is coupled to said tubular axle to rotate said axle and said inner cannula therewith.    
   
   
       29 . The tissue cutting device of  claim 28  wherein said first hydraulic rotary motor includes: 
 a motor housing having opposite ends and defining a pilot port in fluid communication with said hydraulic system to receive said pressurized fluid;    a rotor rotatably disposed within said housing and connected to said axle extending through said housing; and    bearing surfaces at said opposite ends of said housing for rotatably supporting said axle.    
   
   
       30 . The tissue cutting device of  claim 29  wherein said second hydraulic reciprocating motor includes: 
 a hydraulic cylinder having a second pilot port in fluid communication with said hydraulic system to receive said pressurized fluid;    a piston slidably disposed within said cylinder; and    a hollow tube in fluid communication with said proximal end of said tubular axle,    said tube engaged to said piston and operably coupled to said first hydraulic rotary motor to move said first hydraulic rotary motor as said piston slides within said cylinder.    
   
   
       31 . The tissue cutting device of  claim 30  wherein said second hydraulic reciprocating motor further includes: 
 a return spring disposed within said cylinder and biased against said piston to move said piston, said housing and said inner cannula in a direction away from distal end of said outer cannula.    
   
   
       32 . The tissue cutting device of  claim 31  further comprising: 
 a collection trap in fluid communication with said hollow tube; and    a vacuum source in fluid communication with said collection trap to aspirate tissue through said inner lumen, said hollow axle and said tube into said collection trap.    
   
   
       33 . The tissue cutting device of  claim 1  wherein said second hydraulic reciprocating motor includes: 
 a hydraulic cylinder having a pilot port in fluid connection with said hydraulic system to receive said pressurized fluid;    a piston disposed within said cylinder and operably coupled to said inner cannula to move said inner cannula within said outer cannula toward said distal end of said outer cannula;    a return spring disposed within said cylinder and biased against said piston to move said piston and said inner cannula within said outer cannula in a direction away from distal end of said outer cannula.    
   
   
       34 . The tissue cutting device of  claim 1 , wherein said hydraulic system includes: 
 a manual switch disposed between an output line and said source of pressurized fluid, said manual switch operable in a first position to connect said output line to said source, and in a second position to disconnect said output line from said source;    a first pressure actuated switch disposed between said source of pressurized fluid and said first motor, said first switch operable in response to fluid pressure in said output line to connect or disconnect said first motor to/from said source; and    a second pressure actuated switch disposed between said source of pressurized fluid and said second motor, said second switch operable in response to fluid pressure in said output line to connect or disconnect said second motor to/from said source.    
   
   
       35 . The tissue cutting device of  claim 34 , wherein said hydraulic system includes a vacuum source.  
   
   
       36 . The tissue cutting device of  claim 35 , wherein: 
 said vacuum source includes a venturi device; and    said hydraulic system includes a third pressure actuated switch disposed between said source of pressurized fluid and said venturi device, and third switch operable in response to fluid pressure in said output line to connect or disconnect said venturi device to/from said source.    
   
   
       37 . The tissue cutting device of  claim 34 , wherein: 
 said second hydraulic motor includes a hydraulic cylinder having a piston operably coupled to said inner cannula, a hydraulic input connected to said second pressure actuated switch and a return spring disposed within said cylinder and operating on said piston against fluid pressure at said hydraulic input; and    said hydraulic system further includes an oscillating switch disposed between said output line and said second pressure actuated switch, said oscillating switch operable in response to fluid pressure in said hydraulic cylinder to connect or disconnect said hydraulic input to/from said second pressure actuated switch.    
   
   
       38 . A tissue cutting device comprising: 
 an elongated handpiece defining an elongated channel on an outer surface of said handpiece;    a cannula hub mounted to said handpiece and having a fluid port;    a tube connected at one end to said fluid port and having an opposite end connectable to a fluid source, said tube disposed within said elongated channel and sized to be recessed within said channel relative to said outer surface an outer cannula supported at a proximal end by said cannula hub and defining a tissue-receiving opening adjacent a distal end thereof, and    a lumen between said proximal and distal ends in fluid communication with said fluid port of said cannula hub; and an inner cutting member slidably disposed within said lumen of said outer cannula and defining a cutting edge at said distal end operable to sever tissue projecting through said tissue-receiving opening.    
   
   
       39 . The tissue cutting device of  claim 38 , further comprising a fluid source connected to said opposite end of said tube, said fluid source including: a container holding a supply of a fluid; and a valve between said container and said fluid port and operable to control the flow of fluid from said container through said tube.  
   
   
       40 . The tissue cutting device of  claim 39 , wherein said valve is a pinch valve engaged about said tube.  
   
   
       41 . A method for performing a tissue biopsy at a sample site within a patient comprising the steps of: 
 introducing an outer cannula into the patient with a tissue receiving opening adjacent the sample site;    providing a medical treatment through the outer cannula at the sample site;    connecting the outer cannula to a tissue biopsy handpiece having a pneumatic motor-driven tissue cutting cannula with the tissue cutting cannula extending into the outer cannula;    operating the tissue biopsy handpiece to excise tissue through the tissue receiving opening; and    storing the excised tissue for subsequent examination.    
   
   
       42 . A tissue cutting device for removing tissue from a patient comprising: 
 an outer cannula configured for introduction into the patient and defining a tissue-receiving opening adjacent a distal end thereof;    an inner cannula slidably disposed within said outer cannula and defining a lumen from an open distal end to an open opposite end,    said inner cannula further defining a cutting edge at said open distal end operable to sever tissue projecting through said tissue-receiving opening;    a pneumatic motor assembly operably coupled to said inner cannula to rotate and reciprocate said inner cannula within said outer cannula;    a vacuum source fluidly coupled to said inner cannula for generating a vacuum in said lumen of said inner cannula to draw severed tissue therethrough; and    a tissue collection chamber interposed between said vacuum source and said open opposite end of said inner cannula to receive severed tissue drawn into said chamber by the vacuum.    
   
   
       43 . The tissue cutting device of  claim 42 , wherein said tissue collection chamber includes a filter permitting passage of fluid therethrough while retaining the severed tissue within said chamber.  
   
   
       44 . The tissue cutting device of  claim 42  further comprising a pneumatic control circuit having a vacuum switch, the vacuum switch being configured to sense changes in vacuum in order to indicate whether the severed tissue has been drawn completely into said chamber.  
   
   
       45 . The tissue cutting device of  claim 44  wherein the pneumatic circuit further comprises a pressure switch, the pressure switch being configured to sense an end of stroke condition as indicated by an increased backpressure.  
   
   
       46 . The tissue cutting device of  claim 45  wherein the inner cannula advances through the tissue to be severed at a speed that is proportional to the tissue's density.  
   
   
       47 . A tissue cutting device comprising: 
 an outer cannula defining a tissue-receiving opening adjacent a distal end thereof;    an inner cannula slidably disposed within said outer cannula and defining a lumen from an open distal end to an open opposite proximal end, said inner cannula defining a cutting edge at said open distal end operable to sever tissue projecting through said tissue-receiving opening;    a pneumatic rotary motor operably coupled to said inner cannula to rotate said inner cannula within said outer cannula;    a pneumatic reciprocating motor operably coupled to said pneumatic rotary motor to translate said rotary motor and thereby translate said inner cannula within said outer cannula while said inner cannula rotates; and    a handpiece supporting said pneumatic rotary motor and said pneumatic reciprocating motor, said handpiece including a pair of opposite rails, wherein said pneumatic rotary motor includes a pair of opposite outwardly projecting wings configured to be slidably supported on said opposite rails to resist rotation of said pneumatic rotary motor while permitting said pneumatic rotary motor to translate relative to said rails.    
   
   
       48 . The tissue cutting device of  claim 47  further comprising a pneumatic control circuit having a vacuum switch, the vacuum switch being configured to sense changes in vacuum in order to indicate whether the severed tissue has been drawn completely into said chamber.  
   
   
       49 . The tissue cutting device of  claim 48  wherein the pneumatic circuit further comprises a pressure switch, the pressure switch being configured to sense an end of stroke condition as indicated by an increased backpressure.  
   
   
       50 . The tissue cutting device of  claim 49  wherein the inner cannula advances through the tissue to be severed at a speed that is proportional to the tissue's density.