Abstract:
An apparatus and method for performing a medical procedure comprising an elongated shaft having an aperture extending longitudinally therethrough. An actuator tube is positioned within the shaft and a guide wire extends through the tube. A head is attached at one end of the shaft by the guide wire. A specimen is cut by a blade disposed on either the shaft or the head. The device is used to enlarge a lumen that has been occluded with diseased or stenotic tissue.

Description:
This application claims the benefit of provisional application No. 60/190,234 filed on Mar. 17, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a method and device for removal of diseased tissue for disposal or analysis. 
     2. The Prior Art 
     A Lateral Biopsy Device is shown in U.S. Pat. No. 5,653,240 and a device and method for Serial Collection, Storage and Processing is Described in U.S. Pat. No. 5,980,468, both which are hereby incorporated reference. These references disclose techniques for removing tissue by cutting, coring and scraping. The tissue is cut, captured, stored and removed for analysis or disposal from sites deep within body cavities. The tissue is taken from approached long paths to organ lumens as in the gastrointestinal, pulmonary, urological, gynecological, neurological or vascular systems. These methods are useful in many medical applications with modifications appropriate to the specific disease and diagnostic or therapeutic purpose. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide for removal or ablation of diseased tissue for restoring a stenotic or occluded lumen to patency. In the process of the present invention, the diseased tissue is captured within a cone tip or a tube shaft of a lateral biopsy device and retrieved for disposal or analysis. This allows for analysis of serial specimens of tissue to determine the completeness of removal as in ablation of a malignancy or removal of plaque in blood vessels. When removing occluding plaque within a blood vessel, storage and retrieval prevents distal embolization of fragments that would occlude smaller distal blood vessels. 
     Removal of obstructing tissue within a blood vessel lumen requires traversing the vascular lumen leading to the obstruction, passing through the obstruction and coring or scraping the obstructing material into the head or shaft of the lateral biopsy. Traversing a vascular lumen over a guide wire is a standard medical technique. The wire guided lateral biopsy is modified according to the invention by replacing the filiform leader and wire actuator with a central plastic tube attached to the perforated cone blade tip that passes over the previously inserted guide wire. The cone blade tip must pass the obstruction as a dilator or be compressed to traverse the stenosis and expand to serve as a cutting device or an anvil for a shaft blade. Many obstructing lesions are elastic. They compress to allow dilator passage only to reexpand and obstruct. For these lesions the cone tip serves as both a dilator and a cutting device or an anvil. In more rigid lesions, as in peripheral vascular obstructions, the cone dilator must be compressible with a flower petal configuration. The compressive force of the rigid lesion and the catheter shaft traversing the guide wire closes the petals of the cone traversing and dilating the stenosis. The catheter tube shaft blade is then advanced to meet the cone and cores off the obstructing tissue into the shaft. 
     Alternatively, the backward facing cone blade may be pulled back with the central tube and the obstructing tissue captured within the cone tip. For long lesions, as in peripheral arteries, a shaft blade with shaft capture provides a large storage space for cored tissue. A preferred embodiment would have a diameter range of 3 to 10 mm. For short lesions, capture in the tip is sufficient and allows a smaller more flexible lateral biopsy device suitable for smaller arteries 2-3 mm in diameter, such as in the heart. This would be particularly useful for eccentric soft lesions in the coronary arteries. A preferred diameter for these lesions is 2 to 4 mm. 
     For eccentric lesions, the cone blade is modified to have the cutting blade in a specific quadrant allowing removal of the visible lesion with protection of the opposite side of the lumen. This is accomplished by using a radiolucent plastic tip with a radiopaque blade inserted into a segment of the cone. More rigid calcified tissue can be removed by adapting the coring surfaces through a rotating saw blade or abrasive hardened surface. Either rotational or vibrational forces are applied to the blade through a central tube wire lumen of the cone blade tip or by rotating the tube shaft of the shaft blade. 
     In another preferred embodiment, the cutting surface is in the shaft and the cone tip serves to prevent downstream loss of cored material until the tip and shaft close. To close the apparatus, the apposition of the shaft and tip capture the free material in the shaft lumen preventing loss while the instrument is withdrawn. This is an important feature to prevent distal embolization of the cored material in the vascular system. 
     Removal or ablation of neoplastic tissue by cutting, coring or scraping serves to restore a stenosed lumen and remove debris. Completeness of the removal, i.e. excisional biopsy, as determined by microscopical study of the tissue specimens, obviates the need for other therapy such as traditional surgical excision, radiation or chemotherapy. Early neoplastic lesions may have a long latent period before becoming invasive, symptomatic or metastatic. Therefore, as detection of early neoplastic lesions increases, the need for low risk minimally invasive, cost effective removal increases. The bile duct, pancreatic duct, bronchi and ureter are prone to neoplastic transformation. These lumens are difficult to access and treat by traditional surgical methods but easily accessed by endoscopy. Neoplasms in these areas are ideal for biopsy, excision, or debulking by the methods described here. Additionally, ablation of tissue and sealing of bleeding points would be accomplished by electrical heating or coagulation of the tissue surface performed by passing the appropriate electrical current to the metal cone tip or shaft blade. 
     After the lumen is enlarged to the diameter of the first instrument and that instrument is removed, leaving the wire guide in place, serial instruments of larger diameter are passed over the wire guide to further enlarge the lumen. Serial instrument passes allow progressive enlargement of the lumen. For example, a blood vessel or bile duct 10 mm in diameter with a 90% obstruction has a 1 mm lumen that allows passage of a 1 mm wire. Passage of a 2 mm diameter coring instrument would be followed serially by a 4 mm, then 6 mm, 8 mm and 10 mm instruments until the original lumen of 10 mm was restored. Each successive enlargement of the lumen would allow passage of a stiffer more efficient coring device followed by exchange for a stiffer wire guide to provide the necessary increase in coring force required by the larger surface area cored. Each pass traverses a path prepared by its predecessor. This is an advantage of the present invention as compared to balloon dilation or passage of concentric dilators that dilate without tissue removal. In these techniques, although the lumen is restored, in part, a large mass of unwanted tissue is displaced laterally rather than removed. Tissue recoil may close the lumen after dilation or the blood vessel rupture. The unwanted tissue may contribute to the frequent blood vessel restenosis. In cancer, the bulk of a compressed residual tumor may cause restenosis and limits the effectiveness of chemotherapy or radiation. 
     Monitoring is facilitated by radiography with injection of radiopaque contrast or other imaging techniques using the lumen leading to the space between the tip and shaft or the wire guide lumen. In the larger instruments a secondary lumen for contrast injection could be added to the shaft. The injection lumen also allows fluid sampling and pressure measurement. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention. 
     In the drawings, wherein similar reference characters denote similar elements throughout the several views: 
     FIG. 1 shows a wire guided lateral apparatus having the cutting blade on the shaft according to the invention; 
     FIG. 2 shows a wire guide lateral apparatus having the cutting blade on a part of the cone head; 
     FIG. 2A shows the apparatus with a cutting blade entirely surrounding the cone head; 
     FIG. 3 shows the apparatus when cut and sealed for analysis; 
     FIG. 3A shows the apparatus with two caps; 
     FIG. 4 shows the cone head having a perforated flap; 
     FIG. 5 shows the wire guided lateral apparatus having a compressible petal-shaped head and inserted into a lumen; 
     FIG. 6 shows another embodiment of the apparatus having a packing head; 
     FIG. 7 a partial view of the shaft having a central lumen and two side lumens. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now in detail to the drawings and, in particular, with reference to FIGS. 1 through 5, there is illustrated several embodiments of the device according to the invention, which permits serial specimen collection, storage and processing. As shown in FIG. 1, a biopsy device  4  contains a blade  12  disposed on an elongated shaft  10 . An aperture extends through shaft  10  allowing an actuator tube  8  to extend therethrough. A wire guide  15  extends through actuator tube  8  and attaches to a cone-shaped head  20 . Blade  12  is disposed on shaft  10 , as shown in FIG. 1 or on head  20 , seen in FIG.  2 . Biopsy width is constrained by wire guide  15  to approximately 50% of the diameter of cutting blade  12 . Within areas of narrowing, specimen  11  is forced into the cutting chamber and cannot escape except into either the receptacle head or shaft. These external constraints, combined with a conical packing shaft  18  within the head  20  shown in FIG. 6, provide the force to align, pack, and maintain specimen position as well as prevent loss of the specimen  11  when shaft  10  and head  20  are drawn apart for additional procedures. 
     When the device according to the invention is used within an unconstrained space, the force to align, pack, and store the tissue specimens must be provided by the instrument itself. In this circumstance, specimen size is important and a minimum specimen length of twice the blade diameter is assumed to align specimens within the storage space and prevent mixing. This is provided by calibrating shaft movement to that minimum distance. Packing of specimen  11  into shaft  10  and prevention of loss is accomplished by conical packing shaft  18  attached to cutting head  20  that extends into shaft  10  so that packed specimens are constrained. 
     The procedure described above allows the operator to collect and store the specimens in the sequence of acquisition, and allows hands-off processing of the specimens without loss of sequence. The device according to the invention provides for either a cutting head or a cutting shaft. Either of these parts may be used as the receptacle for serial specimens that may then be processed in situ. Each option has distinct advantages and disadvantages that will be made clear by the following: 
     FIG. 3 shows storage of specimens  11  in the shaft  10 , which is a catheter. Shaft storage has the advantage of great storage space in relation to the length of the cutting head without altering operating characteristics of the biopsy device. This option permits retrieval of many samples and a large specimen volume using device diameters of  5 F or smaller where head length is limited to 3 times shaft diameter by the need to traverse narrow tortuous pathways. FIG. 1 shows the cutting blade  12  disposed on the shaft  10 . As shown in FIG. 2, the cutting blade is on the head, and collection of specimens  11  proceeds by moving blade  22  by tension on wire  15 . Blade  22  cuts specimen  11 , which is then drawn down into shaft  10 . Packing head  18  shown in FIG. 6 serves to compress specimens  11  further into shaft  10 . Wire  15  also compresses specimens  11  within shaft  10 . 
     A stopper  40 , shown in FIG. 3, is placed within shaft  10  and connected to wire  15 . Stopper  40  is preferably perforated and serves as an end point to the storage chamber formed by shaft  10 . 
     After the desired number of specimens  11  has been collected and the instrument removed from the patient&#39;s body, head  20  is removed from shaft  10 . Wire  15  is cut and led through a perforated cap  30 , which is placed over the open end of shaft  10 , as shown in FIG.  3 . Wire  15  is then pulled from cap  30  to raise stopper  40  and compress specimens  11  within shaft  10 . 
     If the initial distance between stopper  40  and the end of shaft  10  where cap  30  is placed is known, the length of the shaft containing the specimens to be processed can be determined by measuring the length of wire outside the cap after the wire is pulled through the cap. Shaft  10  can then be cut to this length to create a compact processing cassette for specimens  11 . Cap  30  and stopper  40  allow for exposure of specimens  11  during storage and processing. Alternatively, two caps  30  and  40  can be used as shown in FIG.  3 A. 
     In FIG. 2, cutting blade  22  cuts specimens  11  when head  20  is guided by wire  15 . If stored in head  20 , head  20  is hollow in shape and serves as the storage chamber for specimens  11 . Blade  22  can extend around the entire circumference of head  20 , or can extend around a portion of the head&#39;s circumference. If blade  22  is only on a portion of the circumference, the remaining edge is recessed allowing for easier sliding over lesions. 
     Cutting head  20  is a cylindrical space made of metal or plastic with a proximal facing blade. The headspace has a direct relationship to its diameter, length and the size of the sample. The head diameter must conform to the shaft diameter. Head length is limited by the rigidity produced by head length that impedes maneuverability of the device. Head length must be limited, generally, to between 2 and 10 times shaft diameter to allow easy passage of the device around curves in the endoscope or passage that is to be traversed. The possibility of special cases remains. 
     Head  20  is preferably perforated to allow for packing of the specimens  11  within head  20  by injecting fluid through shaft  10  into head  20 . The fluid pressure causes specimens  11  to be compressed into head  20  and the fluid can then escape through perforated head  20 . 
     When the desired number of specimens  11  have been collected in head  20 , wire  15  is cut and cap  30  is placed over the opening in head  20  to enclose specimens  11 . Cap  30  is preferably perforated to allow the addition of fixative to specimens  11 . Alternatively, a tube of plastic screen can be placed within the hollow head  20 , which is then closed on either end with a packing disc and removal plate. The screen can then be removed from head  20  for further processing and storage of specimens  11 . 
     As shown in FIG. 4, head  20  preferably has a perforated flap  45  formed therein, which can be peeled open to release specimens  11  from head  20  for further processing. 
     FIG. 5 shows head  20 ′ having a collapsible petal shape. This structure is advantageous for situations where there exists more rigid lesions. The petal shaped head  20 ′ is adapted to be compressed as it slides through the lesion or blockage substance. A cone shaped head would not easily slide through such area. When head  20 ′ is pulled back, it collects a specimen. This head structure can also be adapted to compress and thin the blockage in the lumen. 
     FIG. 6 shows an embodiment where blade  22  is disposed on the shaft. Packing head  18  serves to compress the collected specimens into shaft  10 . 
     FIG. 7 shows an embodiment where the shaft comprises a central lumen  64  and two side lumens  63 , connected by slits  68  to allow for fluid injection and sampling. This causes a suction to draw the tissue specimens into the chamber in order of acquisition. 
     A method of compressing the blockage, is to place different diameter heads into the lumen. The different diameter heads are placed over the wire guide allowing progressive enlargement of the lumen. After the lumen is enlarged to the diameter of the first instrument passed and that instrument removed leaving the wire guide in place, serial instruments of larger diameter are passed over the wire guide to further enlarge the lumen. Serial instrument passes allow progressive enlargement of the lumen. For example, a blood vessel or bile duct 10 mm in diameter with a 90% obstruction has a 1 mm lumen that allows passage of a 1 mm wire. Passage of a 2 mm diameter coring instrument would be followed serially by a 4 mm, then 6 mm, 8 mm and 10 mm instruments until the original lumen of 10 mm was restored. Each successive enlargement of the lumen would allow passage of a stiffer more efficient coring device followed by exchange for a stiffer wire guide to provide the necessary increase in coring force required by the larger surface area cored. Each pass traverses a path prepared by its predecessor. 
     In another embodiment, an electrical communication  80 , as shown in FIG. 2A, is supplied to the blade on the head to heat the tissue during the procedure. 
     Accordingly, while only a few embodiments of the present invention have been shown and described, it is obvious that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.