Retrograde Renal Biopsy Device

Abstract

A medical instrument for use in renal biopsy is in the form of an injector tube having a puncturing and scraping tool secured to the end of an inner slide wire and a balloon surrounding the injector tube at the distal end thereof. A second flexible tube is mounted along the outside of the injector tube and connects to the balloon for inflation thereof in the renal pelvis to hold the distal end of the injector tube in fixed relation to the kidney to permit penetration of the scraping tool into the kidney tissue through the epithelium of the renal pelvis.

Description

The present invention relates in general to biopsy devices, and it relates more particularly to such devices which are insertable into a kidney through the urethra, the bladder and the associated ureter.

BACKGROUND OF THE INVENTION

Heretofore, the only reliable method for obtaining a biopsy of renal tissue has been percutaneous. Because of the dangers inherently associated with the percutaneous method, attempts have been made to obtain kidney tissue by insertion of a tissue removing tool through the urinary tract to the bladder and through one of the ureters to the kidney. Such attempts have thus far been unsuccessful.

We believe that the principal reasons for such failures is the inability of the prior art biopsy instruments to penetrate the tough epithelium which lines the renal pelvis. In order to pass through the urethra it is necessary that the tool carrier be relatively flexible, but this flexibility has prevented the application of a sufficient force on the scraping tool to puncture the membrane lining. When the physician pushes on the tool carrier in an effort to push the tool through the membrane-like epithelium, the end portion of the carrier simply bends and curls up inside the renal pelvis.

OBJECTS OF THE INVENTION

Therefore, an object of the present invention is to provide a new and improved instrument for use in retrograde renal biopsies.

Another object of this invention is to provide a new and improved instrument for use in obtaining renal tissue, which instrument includes means enabling penetration of the epithelium which lines the renal pelvis.

A further object of this invention is to provide an instrument for obtaining sample renal tissue, which instrument is relatively easy to use and reliable and safe in operation.

SUMMARY OF THE INVENTION

Briefly, the above and further objects may be realized in accordance with the present invention by providing a thin, flexible injector tube having a puncturing and scraping tool mounted to the distal end portion of a slide wire disposed therein and further having an inflatable balloon mounted at the end of the injector tube for inflation in the renal pelvis to hold the end of the tube in a fixed position in the renal pelvis whereby a sufficient axial force may be applied to the puncturing and scraping tool to push it through the membrane lining of the renal pelvis into the medulla and cortical tissue for obtaining a specimen therefrom.

BRIEF DESCRIPTION OF THE DRAWING

Further objects and advantages and a better understanding of the invention may be had from the following detailed description taken in connection with the accompanying drawing, wherein:

FIG. 1 is a somewhat schematic illustration of a renal and urinary system showing the instrument of the present invention disposed therein;

FIG. 2 is a partially sectioned view of the forward end of an instrument of the present invention particularly showing the deflated balloon and the puncturing and scraping tool;

FIG. 3a is an elevational view of another puncturing and scraping tool embodying the present invention showing the tool in the closed position;

FIG. 3b is a view of the device of FIG. 3a showing the tool in an open, tissue removal position;

FIG. 4 is an elevational view of still another puncturing and scraping tool embodying the present invention;

FIG. 5 is an elevational view of yet another puncturing and scraping tool of the present invention;

FIG. 6a is an elevational view of another embodiment of a puncturing and scraping tool of the present invention; and

FIG. 6b is a partial, elevational view of the tool of FIG. 6a taken from the line 6b--6b thereof.

DETAILED DESCRIPTION OF THE DRAWING

Referring now to the drawing and particularly to FIG. 1 thereof, a retrograde renal biopsy instrument 10 embodying the present invention is shown in a renal tissue specimen collecting position within a urinary tract including the urethra, the bladder, the ureter canal and the associated kidney. As shown in FIGS. 1 and 2, the instrument 10 includes a flexible injector tube 11 in which a flexible wire 12 is slidably mounted. A second tube 13, which is also flexible and of substantially smaller diameter is secured to the injector tube 11 and opens at its forward end into a balloon 14 which surrounds the injector tube 11 near its forward distal end and which is hermetically sealed thereto. The balloon 14 is, when in its deflated condition, a resilient, tubular member having an internal diameter but slightly greater than the external diameter of the injector tube 11. The other end of the tube 13 is connected to an enlarged cylindrical member 15 of conventional construction in catheters enabling the insertion therein of a hypodermic needle to inflate the balloon 14 when it is disposed in the renal pelvis of the kidney.

Fixedly mounted near the forward distal end of the slide wire 12, as best shown in FIG. 2, is a scraping tool 16 having a collar portion fixedly mounted to the wire 12 and a plurality of rearwardly extending finger-like projections 17. The fingers 17 are preferably resilient and inherently biased into the closed position as illustrated in FIG. 2. The ends 18 of the fingers 17 have a sharp outer edge which functions to scrape renal tissue from the medulla or cortex portions of the kidney as the tool is moved rearwardly through the kidney.

As shown, the distal end 19 of the slide wire 12 extends forwardly beyond the end of the scraping tool 16 and, being relatively small in diameter, is used for penetration of the epithelium of the renal pelvis.

In use, the instrument 10 is inserted, with the aid of a cystoscope through the urethra into the bladder and from the bladder into the ureter canal leading to the kidney from which the biopsy specimen is to be obtained. With the aid of a fluoroscope the instrument is guided through the ureter canal into the renal pelvis of the kidney until the end 19 of the slide wire engages the epithelial membrane. The length of the scraping tool 16 and the balloon 14 is such that the balloon 14 is located within the renal pelvis at this time. Air is then injected through the tube 13 to inflate the balloon 14 which expands into the renal pelvis to fixedly lock the forward end of the instrument in place therein at substantially right angles to the adjacent portion of the epithelium. In FIG. 1 the balloon 14 is shown in this inflated condition. The physician then pushes inwardly on the slide wire 12 causing the end 19 thereof to puncture and penetrate the epithelium layer and to be followed by the scraping tool 16 into the medullary tissue of the kidney. It will be apparent to those skilled in the art that if a specimen of the cortical tissue is desired, the wire 12 is pushed farther inwardly so that the cutting tool is disposed within the cortex portion of the kidney. The physician then retracts the slide wire 12 which causes the rear edges 18 of the fingers 17 to scrape along the adjacent portions of the kidney to remove small sliver-like segments thereof which are collected and retained along the inside surfaces of the fingers 18. When the fingers 17 abut the distal end of the injector tube 11, a condition which is readily apparent to the physician, the balloon 14 is deflated through the tube 13 and the entire instrument can then be readily withdrawn from the patient. After retraction from the patient the specimens may be removed from the tool 16 with a small tweezer and placed in specimen bottles in the normal manner.

Referring now to FIG. 3a, there is shown another puncturing and scraping tool 21 which is secured to the injector tube 11 over the end thereof. The tool 21 comprises a cylindrical tube having an integral flap 22 of rectangular shape partially cut therefrom. The outer edge 23 of the flap 22 is sharp and provides the scraping edge of the tool. A puncturing head 24 is secured to the forward end of the slide wire 12 and has a pointed conical end 25 for puncturing and penetrating the epithelium membrane. A stop collar 26 is positioned around and secured to the rearward end of the head 24 for cooperation with a collar 27 fixed in the distal end of the tool 21 so that when the forward shoulder on the collar 26 engages the rearward shoulder on the collar 27, further projection of the cutting head 24 is prevented. A transverse rod 28 is fixed in the tool 21 to limit rearward movement of the puncturing head 24 within the housing cylinder.

In use, the insertion tube 11 is used to feed the tool 21 and the balloon 14 into the renal pelvis. In this embodiment of the invention there is no sharp forward edge on the tool during such insertion. Once the balloon 14 is within the renal pelvis with the forward end of the tool abutting the renal pelvis the balloon 14 is inflated and the slide wire 12 is then pushed forward to cause the head 24 to puncture and penetrate the epithelium. Further pushing of the wire 12 after engagement of the opposing shoulders on the collars 26 and 27 moves the entire scraping tool 21 into the medulla tissue of the kidney. Upon retraction of the tool 21, the finger 22 scrapes the tissue and feeds a sliver of the removed tissue along the inner surface of the finger 22. The tool cylinder is made of a resilient material so that upon completion of the scraping operation the finger 22 is self biased back into substantial engagement with the adjacent edges of the cylinder so as to provide a substantially flush outer surface to facilitate withdrawal of the instrument from the patient.

Referring now to FIG. 4 there is shown another puncturing and tissue removal tool 30 embodying the present invention. The tool 30 comprises a tube 31 fitted over and secured to the injector tube 11 just forward of the balloon 14. The slide wire 12 is provided with a pointed forward end 32 and a centering collar 33 is fixed to the wire 12 for engagement with a pair of transverse rods 34 and 35 to limit the forward and rearward movement of the slide wire 12 in the tube 31. A plurality of rods 36 are mounted in the forward end portion of the tube 31 and extend in a rearward direction at an angle of about 45.degree. into the tube 31. The ends of the rods define an axial opening through which the slide wire 12 may be moved.

In use, the instrument is inserted into the patient until the forward end of the tube engages the epithelium of the renal pelvis. The balloon 14 is then inflated and the slide wire 12 is then pushed forward to puncture the epithelium. The wire 12 is then retracted and the tube 11 is pushed forward into the kidney tissue a sufficient distance to collect a cylinder of tissue in the end of the tube 31. The inherent resiliency of the balloon 14 is sufficient to permit this forward movement of the tube 31. The tube 11 is then retracted and the rods 36 hold the cylindrical specimen in the end of the tube 31. The balloon 14 is then deflated and the entire instrument is removed from the patient.

Referring to FIG. 5, there is shown another puncturing and tissue removal tool 40 embodying the present invention. The tool 40 comprises a tube 41 fixedly connected to the insertion tube 11 just forwardly of the balloon 14. A pair of longitudinal slots 42 and 43 are provided in the tube 41 for receiving a pair of flexible, spring steel, scraping fingers 44 and 45 fixed by an integral collar 46 to the slide wire 12. A collar 49 is fixed to the slide wire 12 for cooperation with a stop collar 50 fixedly mounted in the tube 41 between the collar 49 and a retainer rod 48. As shown, the forward end 51 of the slide wire 12 is pointed to facilitate puncturing of the epithelium of the renal pelvis.

In use, the instrument is inserted into the patient until the forward end of the tool 40 abuts the wall of the renal pelvis. The balloon 14 is then inflated and the slide wire is pushed forward to puncture the epithelium and to push the entire tool into the renal tissue. The slide wire 12 is then retracted and moves rearwardly in the tube 41 until the collar 49 engages the rod 48. A short distance before the collar 49 engages the retainer rod 48 the ends of the fingers 44 and 45 emerge through the slots 42 and 43 spreading outward, due to spring tension, causing beyond the envelope of the tube 41 to scrape a sliver of tissue from the kidney. The slide wire 12 is then pushed forward to cam the fingers 44 and 45 inwardly so as not to interfere with the withdrawal of the instrument from the patient and to hold the specimens during withdrawal. The entire instrument is then withdrawn from the patient.

Referring now to FIGS. 6a and 6b, a puncturing and scraping tool 55 includes a stainless steel tube 56 tightly fitted into the end of a tube 63 slidable in the insertion tube and extending from both ends thereof. The tube 56 is bonded to the tube 63 with a suitable cement. The tube 56 has an end surface 57 cut on a bias relative to the axis of the tube to provide a sharp cutting edge. A stainless steel wire 58 is slidably mounted in the tube 63 and extends beyond the rear end thereof for manipulation thereof by the physician. The forward end portion of the wire 58 is flattened beginning at 59 and the tube 56 is crimped at 60 to provide a stop for limiting forward relative movement of the slide wire 58.

The wire 58 is provided with a reverse bend at the forward end portion to provide a flat finger 62 lying parallel to the face 57 of the tube 56 and a camming surface 61 adapted to engage the adjacent edge of the tube 56 when the slide wire 58 is pulled downwardly as shown in FIGS. 6a and 6b.

In use the slide wire is retracted to withdraw the portion 61 into the tube 56 a sufficient amount to move the finger 62 against the surface 57 whereby the external diameter of the tool 55 is less than the external diameter of the insertion tube and the tube 63 is withdrawn into the insertion tube. The entire instrument is then inserted into the patient until the tool enters the renal pelvis. The balloon is then inflated and the tube 63 is pushed forward to expose the tool which punctures the epithelium of the renal pelvis and extends the desired distance into the renal tissue. The slide wire is then pushed forward and retracted to cause the end to clip off a piece of renal tissue and capture it in the end of the tube 56. The tube 63 is then withdrawn into the insertion tube, the balloon is deflated and the entire instrument is then withdrawn from the patient.

While the sizes and dimensions of the tools of the present invention are not critical the following dimensions have been found to provide satisfactory devices:

balloon 14 (deflated diameter) 0.156 inch slide wire 12 (diameter) 0.020 inch fingers 17 (maximum diameter) 0.1875 inch tube 21 (outside diameter) 0.069 inch tube 41 (outside diameter) 0.069 inch tube 56 (outside diameter) 0.025 inch wire 58 (unflattened) 0.020 inch wire portions 60 and 61 0.013 .times. 0.023 inch

While the present invention has been described in connection with particular embodiments thereof, it will be understood that those skilled in the art may make many changes and modifications without departing from the true spirit and scope thereof. Accordingly, the appended claims are intended to cover all such changes and modifications as fall within the true spirit and scope of the present invention.

Claims

What is claimed is:

1. A biopsy instrument for obtaining a sample of kidney tissue, comprising

an elongated flexible insertion tube for insertion through the urethra, the bladder and the ureter into the renal pelvis of the kidney,

a flexible slide wire slidably disposed in said insertion tube and extending from both ends thereof,

a tissue removal tool fixedly secured to the foreward end portion of said slide wire,

said tool having a scraping edge for insertion into the tissue of said kidney and for removing therefrom a tissue sample,

an inflatable resilient balloon affixed to and surrounding the foreward end of said insertion tube in proximity to said tool so as to be positionable within the renal pelvis of said kidney and, when inflated to hold the foreward end of said insertion tube in a substantially fixed position in the renal pelvis, and

a passageway extending from the interior of said balloon to the rearward portion of said instrument for use in inflating said balloon after it is positioned within said renal pelvis,

whereby the inflated balloon holds the foreward end of said insertion tube in a substantially fixed position within said renal pelvis to permit the physician to cause said tool to penetrate the epithelium by pushing the rearward end of said slide wire into said insertion tube.

2. A biopsy instrument according to claim 1 wherein said balloon is a tubular, resilient member surrounding said insertion tube.

3. A biopsy instrument according to claim 2 wherein said tool comprises

a rearwardly extending finger for scraping tissue from an organ to be examined.

4. A biopsy instrument according to claim 3 wherein said finger is resilient.

5. A biopsy instrument according to claim 3 wherein said tool comprises

a collar from which said finger and at least one additional finger extend.

6. A biopsy instrument according to claim 1 wherein said tool further comprises

a tubular member through which said slide wire slidably extends, and

stop means mounted on said tubular member and on said slide wire for limiting forward and rearward movement of said slide wire relative to said tubular member.

7. A biopsy instrument according to claim 6 wherein said finger is integral with said tubular member.

8. A biopsy instrument according to claim 7 wherein said tubular member is provided with a slot through which said finger extends.

9. A biopsy instrument according to claim 1 wherein said tool comprises

a rearwardly extending tissue removal and collection finger on the end of which said scraping edge is provided.