Abstract:
A sleeve is provided for placing over a flexible endoscope. The sleeve has a port between its distal and proximal openings and the port is connected to a vacuum source. Once the endoscope is retracted proximal to the suction port, the sleeve&#39;s proximal opening is sealed off and the entire sleeve is turned into a suction lumen. Devices and methods in accordance with the invention provide improvement in removing materials from body cavities, especially in removing stones from the upper urinary tract.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation of U.S. patent application Ser. No. 09/579,995, filed May 26, 2000, now U.S. Pat. No. 6,547,724, which in turn, claims priority to and the benefit of U.S. provisional patent application Ser. No. 60/136,007 filed on May 26, 1999, both of which are incorporated herein by reference. 

   TECHNICAL FIELD 
   The present invention relates to methods and devices useful for removing unwanted materials such as calculi, deposits and tissues from a body cavity. 
   BACKGROUND INFORMATION 
   Currently, urologists performing a procedure known as percutaneous nephrolithotomy (PCNL) often use a rigid nephroscope, a flexible cystoscope, or a flexible ureteroscope in conjunction with flexible baskets or graspers to remove stones and stone fragments from the renal cavity of a patient. A rigid or semi-rigid scope is often used to treat the lower urinary tract, while accessing upper urinary tract needs a flexible scope for negotiating the tortuosity when the ureter crosses the iliac vessels. Because of the high degree of deflexibility required for a scope to travel to the upper urinary tract, in terms of both active and passive deflection, adding accessories to the working channels of a flexible ureteroscope, which compromises the scope&#39;s overall deflexibility, is often undesirable. See,  Smith&#39;s Textbook of Endourology , Vol. 1, Ch. 32 (1996, Quality Med. Pub. Inc.). 
   To remove stones and/or stone fragments, urologists generally use an endoscope coupled with accessories such as baskets or graspers. The use of accessories in the working channels of the endoscope becomes problematic when it comes to treating upper urinary tract because of added constraints on the scope&#39;s deflexibility and hence access to the target. Also, using a basket or grasper through a flexible scope can be technically challenging due to the high level of manual dexterity required of an operator to manipulate effectively the basket or grasper to capture and retrieve the stone(s) and/or stone fragment(s). Procedures that use baskets or graspers also are time-consuming since the entire scope must be retracted to remove stone(s) or fragment(s) from the renal cavity. If there are multiple stone(s) or fragment(s) to be removed from a specific area, then every time a flexible scope is retracted, the urologist must maneuver his/her way back to the desired location to get the next stone or fragment. This obviously increases the level of tissue trauma to the patient and the risk of damage to the urinary tract. 
   Urologists also use lithotripters to crush stones into fragments that are passable through the urinary tract. Lithotripsy devices have been developed which utilize electrohydraulic probes, ultrasonic probes, electromechanical impactors, laser fibers and so on. An example of a lithotripter is a system known as “Lithoclast” that is commercially available from Boston Scientific Corporation of Natick, Mass. Again, the addition of a lithotripter will compromise the scope&#39;s deflexibility and thus will limit its use in treating the upper urinary tract. Such limitation also affects the breaking power of a lithotripter and renders treatment of upper urinary tracts longer and less successful. 
   Suction channels, sometimes with a lithotripter in a parallel working channel, have been integrated into scopes to help remove stones and fragments. For instance, a suction system known as “Lithovac,” also available from Boston Scientific Corporation of Natick, Mass., can be matched with the “Lithoclast” lithotripter system to remove stones and/or stone fragments from the renal cavity of a patient during a PCNL procedure. Because an integrated suction channel will further decrease the deflexibility of a flexible scope, the use of lithotripters with integrated suction is limited to renal areas that can be accessed by a rigid device. And even in such cases, the suction channel is often highly limited in its diameter and hence the suction capacity. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is thus to provide an effective and efficient means for the removal of stones and other unwanted materials from cavities only accessible by a flexible endoscope, such as the upper urinary tract. A more general objective is to provide a suction means that can remove large targets and be suitable for treatment of all cavities in the body including those accessible by rigid instruments. 
   The present invention provides devices and related methods for the removal of unwanted materials such as calculi, deposits, tissues (e.g., polyps and tumor cells) and fluid from a patient&#39;s (human or animal) body cavity. The invention achieves these objectives by providing a sleeve that is to be placed over an elongated instrument such as a flexible endoscope. The sleeve wall contains a port disposed between the distal opening and proximal opening; the port divides the lumen into a distal lumen and a proximal lumen. When the distal end of the inserted instrument is retracted beyond the port, a seal prevents direct passage of gas or liquid between the sleeve&#39;s proximal opening and the port. Hence, a passageway is created between the sleeve&#39;s distal opening and the port, and through a portion of the sleeve lumen. When the port is connected to a vacuum source, materials from a treatment site can be removed through the suction passageway. When the port is connected to a source of positive pressure (liquid or gas), it results in irrigation or ventilation of the treatment site through the sleeve&#39;s passageway. 
   Because the passageway so created may have a cross-section as large as the entire cross-section of the sleeve, effective removal of large targets becomes possible. This maximization in the cross-section of the passageway offers a significant advantage over the removal capacity of known suction lumens that are integrated in a rigid, semi-rigid or flexible endoscope. Particularly for treatment of upper urinary tracts where scope deflexibility is crucial, the invention provides the possibility for a flexible scope containing a lithotripter in its working channels to also possess a suction function. The device of the invention also eliminates the need for using flexible forceps and flexible baskets through the working channels of flexible scopes, an operatively difficult and inefficient procedure for treating upper urinary tracts. 
   The time required to remove stones and their fragments is also substantially reduced with the excellent suction capability of the device of the invention. Because the sleeve remains positioned inside the body cavity, an operator can reinsert the instrument to the earlier position through the guidance of the sleeve. This saves the operator from re-performing the often time-consuming and technically-demanding procedure of maneuvering the medical instrument inside a body cavity such as the tortuous renal cavity. This also saves the patient from further discomfort and tissue trauma. 
   The sleeve is designed to receive an elongated medical instrument such as a scope and more particularly, a flexible scope such as a flexible cystoscope or a flexible ureteroscope. Therefore, the sleeve can take any shape to accommodate the shape of the instrument, and different segments of the sleeve may assume different shapes. The preferred shape of the sleeve is substantially cylindrical where a cross-section of the sleeve is substantially circular or oval. In a preferred embodiment, the port is connected to a vacuum pump. When the instrument is slid back until its distal end is proximal to the suction port, the space inside the sleeve previously occupied by the instrument becomes a suction passageway. Suction in the distal lumen is made possible by the presence of a seal in the sleeve&#39;s proximal lumen. The seal may be in the form of an interference fit between the sleeve member and the instrument (e.g. around its radial surface). 
   The sleeve can have multiple lumens. Such lumens may be defined by a permanent partition integral with the sleeve, or by temporary structures that may be separated from the sleeve, or it may be created by the insertion of an instrument whose outer diameter is less then the inner diameter of the sleeve. At least one of these lumens may be connected to an aperture and serve as a channel for suction, irrigation or ventilation even when the distal end of the instrument is in the distal lumen. This aperture can be the same port that divides the sleeve lumen into the distal lumen and the proximal lumen. Alternatively, this aperture can be a separate opening. 
   The sleeve may be used to provide concurrent irrigation to the treatment site. This will prevent collapse of the renal cavity during suction by providing enough fluid flow to the renal cavity to counteract the suction force pulling material and fluid out of the renal cavity. A separate irrigation channel can also be integrated into the sleeve. 
   In some embodiments of the invention, the sleeve and the instrument are integrated into one unit. In other embodiments of the invention, the sleeve and the instrument are separable and the sleeve becomes disposable after use. This allows it to be manufactured inexpensively and does not require the operator to purchase any additional instrumentation in order to use the sleeve. 
   The wall forming the sleeve lumen may be made of a rigid, semi-rigid or flexible material. In a preferred embodiment where the sleeve is to enclose a flexible scope used for treating the upper urinary tract, the sleeve is made of flexible materials. As a result, the sleeve will not significantly impact the deflection capabilities of the flexible scope. In addition, the inner and/or outer surface of the sleeve may be coated partially or completely with a lubricious material to further reduce any impact on the deflexibility of the scope, allowing easy positioning and maneuvering around the renal cavity. In another embodiment, on the other hand, there may be structures such as reinforcement materials in the sleeve that prevents the sleeve from ovaling, kinking, or collapsing as a result of bending, manipulation, or suctioning of stone(s) or fragment(s). 
   The sleeve has a seal that prevents the direct passage of fluid between the port and the proximal opening of the sleeve. An example of the seal is an airtight connection with a portion of the enclosed instrument when the instrument is pulled back beyond the port. When the port is connected to a vacuum source, this seal in that segment of the sleeve allows the formation of a suction passageway from the sleeve&#39;s distal opening to the suction port. An example of such a seal is a compressive clamp or an O-ring that tightens around the radial surface of the enclosed instrument. The instrument can also be force-fitted into the sleeve and the force-fitting remains proof when the distal end of the instrument is retracted into the proximal lumen. In that case, the seal comprises a portion of the sleeve&#39;s inner surface that is in contact with the instrument. This seal may continue to prevent the direct passage of gas or liquid between the proximal opening and the port even when the distal end of the instrument is distal to the suction port. The seal may comprise a locked position and an unlocked position. 
   The port is connected to a source of pressurized fluid (gas or liquid), such as a pump. The source may generate negative pressure that causes suction, or it may generate positive pressure to inject fluid (such as saline solution or air). A switch, such as a trumpet valve assembly, may be used to switch the port between the suction mode and the injection mode. The port may be further connected to an on/off switch, and/or a pressure-regulator. 
   The foregoing and other objects, aspects, features, and advantages of the invention will become more apparent from the following description, figures, and from the claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. 
       FIG. 1  is a side view of an embodiment of the invention. 
       FIG. 2  is a further illustration of the embodiment depicted in FIG.  1 . 
       FIGS. 3A-3B  are cross-section views, taken along line b—b in  FIG. 2 , showing the lumens of various embodiments of the sleeve. 
       FIG. 3C  is a cross-section view, taken along line a—a in  FIG. 1 , showing the lumen of an embodiment of the sleeve with an instrument inside. 
       FIG. 4A  is a prospective view of an embodiment of the seal in accordance with the invention. 
       FIG. 4B  is a schematic view of another embodiment of the seal in accordance with the invention. 
   

   DETAILED DESCRIPTION 
   Reference is now made to the drawings which are presented merely for the purpose of illustrating the general principles of the invention. 
   Referring to  FIG. 1 , an embodiment of the sleeve in accordance with the present invention comprises a tubular member  10  that is designed to be placed over an elongated instrument  50 , such as a scope as illustrated here. The tubular member  10  has a distal opening  15  and a proximal opening  25  and a third radial opening  20 . Opening  20  is a port connected to a source of pressurized fluid (not shown). The port  20  divides the lumen of the sleeve into two segments: the proximal lumen  30  between the proximal opening  25  and the port  20 , and the distal lumen  5  between the distal opening  15  and the port  20 . The sleeve further comprises a seal  40  that prevents direct passage of gas or liquid between the proximal opening  25  and the port  20 . In one mode as illustrated in  FIG. 1 , the elongated instrument  50  is inserted all the way inside the sleeve and performs its intended functions. In the case of an endoscope, once its distal end  52  is inserted into the distal region of the sleeve, it can be used to carry out diagnostic and therapeutic functions. In this mode, the sleeve  10  is a protective cover or sheath and provides sterility and insulation. 
   In  FIG. 2 , the same embodiment of the invention is shown in a different mode. Here, the inserted instrument  50  is pulled back in the sleeve  10 . When the distal end  52  of the instrument  50  is disposed proximal to the port  20 , the seal  40  prevents the direct passage of gas or liquid between the proximal opening  25  and the port  20 . In this particular illustration, the seal  40  comprises a ring clamp  42  made of elastic steel that locks and exerts a compressive force on a portion of the instrument  50 &#39;s radial surface. Once the clamp  42  is locked, it provides an interference fit between the proximal end of the sleeve  10  and a portion of the outer, radial surface of the inserted instrument  50 . Clamp  42  can also be in the locked position and seal off the proximal end of the sleeve  10  even when instrument  50  is fully inserted in the sleeve such that its distal end  52  is distal to port  20 . If this is the case, and if the port  20  is connected to a vacuum source, any space in the sleeve  10  not occupied by instrument  50  will become a suction lumen when the distal end  52  is in the distal lumen  5 . In any event, when the instrument is partially retracted such that its distal end  52  is in the proximal lumen  30 , the entire distal lumen  5  becomes a passageway for materials to flow between the distal opening  15  and port  20 . 
   A major advantage of the present invention is the maximization in the cross section of the passageway which can be used for suction. The outer diameter of the sleeve  10  can be, in one embodiment, approximately 18 Fr which will allow the device to travel through most infundibula. In one embodiment, the inner diameter of the sleeve is sized to allow suction and removal of stones and fragments up to 5 mm in diameter when the distal end  52  of the scope is in the proximal lumen  30 , and up to 2 mm in diameter when the distal end  52  is in the distal lumen  5 . 
   While in the preferred embodiment, the sleeve  10  is detachable from the instrument  50  and hence disposable, it shall be recognized that the invention further contemplates integrating the two into one unit. The sleeve and the instrument may contain structures such as corresponding grooves and protrusions to customarily fit each other and provide effective sealing at least when the distal end  52  of the instrument is in the proximal lumen  30 . 
   The wall forming the sleeve lumen may be made of a rigid, semi-rigid or flexible material. The sleeve can be manufactured through thermoplastic extrusion or injection molding. In a preferred embodiment where the sleeve is to enclose a flexible scope in treating the upper urinary tract, the sleeve is made of a flexible material, preferably of extrudable plastic materials, such as polyurethane, polyethylene, polyethylene teraphthalate, and/or polyvinyl chloride. As a result, the sleeve will not significantly impact the deflection capabilities of the flexible scope, and the scope  50  is able to achieve a deflection of about 120 to 150 degrees with the sleeve  10  over the scope. 
   In some embodiments of the invention, the sleeve is constructed in such a manner, as recognized by those skilled in the art, to prevent ovaling, kinking, or collapse as a result of bending, manipulation, or suctioning of stones or their fragments. One example is to add reinforcing materials in the form of wires or an intermediate layer in the lumen wall of the sleeve  10 . Another example is to insert support rings, inflatable tubes, helical members and other structures such as described in U.S. Pat. No. 6,017,339 to Sadamasa, U.S. Pat. No. 5,569,219 to Hakki et al. and U.S. Pat. No. 5,947,940 to Beisel, all of which are incorporated herein by reference. In a preferred embodiment, the sleeve is passively deflected since it relies on the use of a flexible scope for positioning within the renal cavity, that is, the sleeve is flexible and bends or deflects as an operator controllably bends and deflects the scope. 
   In one aspect of the invention, the inner and/or outer surface of the sleeve  10  may be coated partially or completely with lubricious materials to allow easy positioning and maneuvering around the renal cavity. Such coating(s) may also help offset any impact on the deflexibility of the flexible scope due to the durometer of the sleeve. 
   In another aspect of the invention, the sleeve may contain multiple lumens defined by partition structures. Apertures connected to these lumens may be part of the sleeve&#39;s distal opening, proximal opening, or its radial surface. As shown in  FIG. 3A , the sleeve  10  may contain, for example, three lumens defined by partition structure  6 . Lumen  1  is sized for insertion of the medical instrument (not shown). One of the lumens can be used as an irrigation or ventilation channel  3  connected to a source of pressurized fluid. Lumen  2  illustrates another working channel. 
   The lumens can be substantially co-axial, as shown in FIG.  3 B. All or one of the outer lumens may be used as the irrigation/ventilation channel  3  connected through an aperture (not shown) to a source of irrigation or ventilation. That aperture may be the port  20 . The channel  3  can run along the length of the sleeve  10 , which prevents the collapse of the cavity under treatment during suction by providing enough fluid flow to the cavity to counteract the vacuum caused by suction. 
   Referring to  FIG. 3C , when the outer diameter of the instrument  50  is less than the inner diameter of the sleeve  10 , a lumen  8  is created by virtue of space in the sleeve unoccupied by the instrument. Lumen  8  can be connected, through an aperture in the sleeve&#39;s proximal end or in the sleeve&#39;s radial surface, to a source of pressurized fluid and be used as an irrigation or ventilation channel. Lumen  8  may also be connected to the port  20 , and serve as a suction passageway when the distal end of the instrument  50  is in the distal lumen and the port  20  is connected to a vacuum source. A continuous low-pressure flow may be supplied through lumen  8  to remove stones or fragments while the instrument  50  operates. Furthermore, since the port  20  may be further connected to a source of positive pressure and be used to inject fluids or gases to the treatment site (described below), lumen  8  may be used as an irrigation or ventilation channel in that manner. 
   In one aspect, the seal  40  can assume many different structures and configurations. As depicted in  FIGS. 1 and 2 , and in more detail in  FIG. 4A , the seal  40  can be a compressive clamp  42  or an O-ring made of steel. Referring to  FIG. 4A , an embodiment of the clamp  42  in accordance with the invention is in the shape of a bracelet that is to be placed over the proximal portion of the sleeve (not shown). The clamp  42  may include two arms  41 , connected by a hinge  48 . The two arms  41  lock through two tooth-like structures  43 , which are complementary in shape and will lock when an operator squeezes them together and past each other. There are small knob-like protrusions  46  fixed on structures  43 . The operator can unlock structures  43  by pushing the two knobs  46  outward simultaneously. There can be additional structures attached inside the arms  41  where contact with the sleeve is made. An example of such additional structures is a pad made of materials such as plastics, rubber, leather or sponge. When the operator locks the clamp  42  around the proximal portion of the sleeve, the clamp  42  tightens the sleeve and provides an interference fit between the sleeve and the medical instrument inside. The option of having other structures between the sleeve and the instrument is not contemplated as negating the existence of an interference fit. Other devices known to one skilled in the mechanical art that can be used to seal off the sleeve&#39;s proximal opening against the enclosed instrument, such as rubber bands and devices described in U.S. Pat. No. 5,775,325 to Russo, incorporated herein by reference, are also contemplated by the present invention. 
   Referring to  FIG. 4B , in another embodiment, the seal  40  can comprise a portion of the inner surface of the sleeve itself that protrudes inward as a constrictor  70 . This ring of protrusion  72  between the proximal opening  25  and the port  20  can be made of the same material and be integral to the sleeve or of a different material that has a higher or lower durometer. The size of constrictor  70  is designed to provide an interference fit between the sleeve&#39;s inner surface and the inserted instrument. Alternatively, the constricting ring may be disposed on the outer surface of the sleeve and exert inward radial forces on the sleeve that compress the inner surface tightly against the surface of the instrument. The constricting ring may reside in a groove carved on the outer surface of the sleeve. 
   If the inner diameter of the sleeve and the outer diameter of the instrument are substantially the same and therefore the instrument is force-fitted into the sleeve, then the seal  40  comprises portions of the sleeve&#39;s inner surface and the instrument&#39;s outer radial surface that are in contact with each other. 
   Referring back to  FIGS. 3A and 3B , in certain embodiments, such as those depicted here, where there are lumens other than lumen  1 , which is for insertion of the instrument  50 , the seal  40  (not shown) may or may not seal off those lumens. Therefore, the irrigation or ventilation channel  3 , for example, may continue to transport fluids to the treatment site, when the seal  40  seals off the proximal end of lumen  1 . The route where fluids travel from the sleeve&#39;s proximal opening, through an irrigation or ventilation channel, to the sleeve&#39;s distal opening and then to the port  20  is not contemplated as a “direct” passage of fluids between the proximal opening and the port. 
   The port  20  is connected to a source of pressurized fluid, such as a pump. In one aspect of the invention, the source may generate either negative pressure to cause suction or positive pressure to inject fluid or air to the site of treatment. Alternatively, the source of positive pressure (e.g., for irrigation or ventilation) may be separate from the source of negative pressure (e.g., a vacuum pump) and the port may be linked to both. In that case, the port may be further connected to a device allowing the operator to switch from one connection to the other. An example of such a device is a trumpet valve assembly, described in U.S. Pat. No. 5,449,145 to Wortrich, incorporated herein by reference. A source of pressurized gas or liquid such as a gravity-based drip-irrigation system is contemplated by the present invention as a source of positive pressure. In any event, the seal  40  prevents direct passage of gas or liquid between the port and the sleeve&#39;s proximal opening. 
   Whether the suction port is linked to a source of positive pressure, negative pressure or both, the suction port may be further connected to a switch or valve that turns the pressure on and off (e.g. a trumpet valve), and/or a pressure-regulator. Examples of such control devices are described in publications such as U.S. Pat. No. 5,882,348 to Winterton et al., U.S. Pat. No. 5,938,589 to Wako et al., and U.S. Pat. No. 5,730,727 to Russo, all incorporated herein by reference. 
   A further aspect of the invention addresses the risk of scope damage from stones and their fragments hitting the lens at the distal end of the scope inserted in the sleeve. A separate soft bumper, mesh, or other like barrier structure can be attached to the distal end of the scope for lens protection. A stream of irrigating fluid will also cushion the scope against the impact of stones and their fragments. The irrigation will also help clean the lens for better viewing. 
   Different embodiments and various features of the invention can be combined in the same device in accordance with the invention. Variations, modifications, and other implementations of what is described herein will occur to those of ordinary skill in the art without departing from the spirit and the scope of the invention as claimed. Accordingly, the invention is to be defined not by the preceding illustrative description but instead by the spirit and scope of the following claims.