Abstract:
Apparatus and method for retrieving a remotely located device equipped with a magnetic coupler is provided. The apparatus includes a magnetic coupling carried at an end of an elongate member for attracting the magnetic coupler of the remotely located device, and aligning the magnetic coupler with the magnetic coupling. A frictional engagement device, substantially housing the magnetic coupling therein, is adapted for trapping the magnetic coupler therein such that a retrieval force applied to the apparatus is transferred to the remotely located device via the frictional engagement device to thereby facilitate sure retrieval of the device as by magnetic mechanical entrapment.

Description:
This is a continuation of application Ser. No. 09/724,239 filed on Nov. 28, 2000 now U.S. Pat. No. 6,551,304, which is a regular application filed under 35 U.S.C. §111(a) claiming priority under 35 U.S.C. §119(e) (1), of provisional application Ser. No. 60/168,306, having a filing date of Dec. 1, 1999, filed under 35 U.S.C. §111(b). 
    
    
     BACKGROUND OF THE INVENTION 
     The following disclosure relates to an apparatus and method for retrieving a device which is positioned within a remote location. This location is preferably located within the human body, and more preferably within the human urethra. 
     The subject invention provides for apparatus and methods for retrieving devices remotely when access otherwise would require more expensive and/or complex procedures such as optical viewing, ultrasonic detection, x-ray, fluoroscopy and grasping with a forceps. Remote (i.e. indwelling) devices may be of many configurations, with medical or other industrial applications. With human medical applications, the remote device could consist of, though not be limited to, intraurethral devices such as stents, shunts or valved devices. Urethral (or uteral) devices may be sized from a total profile in diameter from 2 to as large as 40 French, with device length likely to vary according to the application. 
     Features and methods of the embodiments of this application may be compatible with the following applications, incorporated herein by reference: URETHRAL DEVICE WITH ANCHORING SYSTEM, Ser. No. 09/411,491, filed Oct. 4, 1999, now U.S. Pat. No. 6,221,060 issued on Apr. 24, 2001; URETHRAL APPARATUS WITH POSITION INDICATOR AND METHODS OF USE THEREOF, Ser. No. 09/340,491, filed Jun. 30, 1999, now U.S. Pat. No. 6,258,060 issued on Jul. 10, 2001; MAGNETICALLY LATCHED DEFORMABLE DOME URINARY FLOW CONTROL APPARATUS AND METHOD OF USE THEREOF, Ser. No. 60/179,038 filed Feb. 1, 2000, filed as a regular application on Jan. 26, 2001 and assigned Ser. No. 09/772,088, now U.S. Pat. No. 6,527,702 issued on Mar. 4, 2003. 
     SUMMARY OF THE INVENTION 
     Apparatus and method for retrieving a remotely located device equipped with a magnetic coupler is provided. The apparatus includes a magnetic coupling carried at an end of an elongate member for attracting the magnetic coupler of the remotely located device, and aligning the magnetic coupler with the magnetic coupling. A frictional engagement device, substantially housing the magnetic coupling therein, is adapted for trapping the magnetic coupler therein such that a retrieval force applied to the apparatus is transferred to the remotely located device via the basket to thereby facilitate sure retrieval of the device as by magnetic mechanical entrapment. 
     More specific features and advantages obtained in view of those features will become apparent with reference to the drawing figures and DETAILED DESCRIPTION OF THE INVENTION. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  schematically shows the apparatus of the subject invention being advanced toward a remotely deployed device for which retrieval is sought; 
         FIG. 2  schematically shows a portion of the remotely deployed device coupled to the apparatus of  FIG. 1 ; 
         FIG. 2A  schematically shows the magnetic coupler captured within the basket of the apparatus of  FIG. 1 , and axially aligned with respect to the magnetic coupling; 
         FIGS. 3 and 3A  schematically show an alternate embodiment of the subject invention illustrating the relationship between the basket and the magnetic coupling, the basket being selectively axially retractable relative to the magnetic coupling; 
         FIGS. 4 and 4A  schematically show a further embodiment of the subject invention illustrating the relationship between the basket and the magnetic coupling, namely that the basket is capable of radial collapse upon being selectively axially retracted relative to the magnetic coupling; and, 
         FIGS. 5 ,  5 A and  5 B schematically show yet another embodiment of the subject invention illustrating a non-basket mechanical capture structure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The apparatus and method of this invention requires only simple equipment. The securing is accomplished by a simple magnetic coupling apparatus incorporated functionally with the remote device.  FIG. 1  illustrates the remote device. The remote device  10  is equipped with a tether  16  at distal extremity  14  from the remote device  10  within passageway  24  as illustrated in  FIG. 1 . A magnetic coupler  22  is attached distally to tether  16 . This magnetic coupler  22  is constructed of a material that is magnetic in properties, or further is magnetized. 
     The tether  16  is sized and secured in a manner such that it has sufficient mechanical strength to withstand the force required to pull the remote device from the location and its specific environment through the necessary passageway  24 . The size of the device and the environment of the passageway  24  will determine the mechanical requirements of the tether  16  and the method of attachment. The magnetic coupler  22  is linked magnetically with the retrieval tools as illustrated by the disclosed embodiments of retrieval devices.  FIG. 1  illustrates the retrieval tool  30  of the first embodiment located within passageway  24  near the distal extremity  14  of remote device  10 . 
       FIG. 1  illustrates an example of a indwelling device  10  which is retrievable from a urinary tract environment. The indwelling device  10  consists of a proximal extremity  12 , and a distal extremity  14 . The tether  16  has a proximal extremity  18 , and a distal extremity  20 . Tether proximal extremity  18  is secure at distal extremity  14  of indwelling device  10 . A magnetic coupler  22  is secured to distal extremity  20  of tether  16 . This magnetic coupler  22  is constructed of a material that is magnetic in properties, or magnetized. Tether  16  may be secured to the magnetic coupler  22  at any radial orientation. Securing of the tether  16  radially away from the magnetic coupler  22  centerline provides a torque upon separation which is useful in entrapment. The preferred magnetic material for magnetic coupler  22  is magnetized Samarium Cobalt 20, whereas the preferred magnetic material for magnetic coupling  34  magnetization is Neodynium 27. All the magnetic materials are preferably coated with a suitable coating for biocompatable inertness such as Class VI epoxy or vapor deposited paraxylene. 
     Tether  16  is sized and secured in a manner such that it has sufficient mechanical strength to withstand the force required to pull the indwelling device from the location and its specific environment through the necessary passageway  24 . The size of the device and the environment of the passageway  24  will determine the mechanical requirements of the tether  16  and the method of attachment. The preferred material for the retrieval tether is USP class VI silicone coated braided silk suture in a size 1/0. This suture size provides a break load maximum of 8.6 pounds which is more than sufficient for most applications. 
       FIG. 2  illustrates an expanded partial sectional view of retrieval device  30  of the first embodiment in a coupled state with indwelling device  10 . Amplification device  64  is further shown uncoupled. The amplification device  64  assists the blind coupling procedure by providing an audible feedback when coupling occurs between magnetic coupling  34  and magnetic coupler  22  of indwelling device  10 . During the retrieval procedure, a retrieval device  30  is advanced towards the magnetic coupler  22  of the indwelling device  10 . As the retrieval device  30  is provided with a magnetic coupling  34 , when the retrieval device  30  of the preferred embodiment is advanced to the proximity of the magnetic coupler  22 , the magnetic coupler  22  is drawn towards the magnetic coupling  34  of the retrieval device  30 . The retrieval device of this embodiment is configured for retrieval by the use of a basket  40  which allows for retrieval without manipulation of any moving parts within the retrieval device  30 . 
     Referring to  FIGS. 1 ,  2  and  2   a , the construction of the retrieval device  30  is herein described from the proximal extremity  44  toward the distal extremity  48 . Basket  40  extends from magnet housing  46  which is attached to elongate member  36  to proximal extremity  44 . Magnet coupling  34  is shown located within basket  40 . Hub  70  is secured near distal extremity  48  of elongate member  36 . 
     The retrieval of the indwelling device  10  is accomplished when the retrieval device  30  is advanced within the passageway  24  ( FIG. 1 ). Retrieval device  30  is advanced towards indwelling device  10  until magnetic coupling  34  and the magnetic coupler  22  are attracted and move towards each other vis-a-vis cooperation of their magnetic fields. The tether  16  is flexible and thus provides for freedom of movement of the magnetic coupler  22 . The magnetic coupler  22  and the magnetic coupling  34  will then mate. The magnetic fields between the magnetic coupler  22  and the magnetic coupling  34  cause the axis of the magnetic coupler  22  and the magnetic coupling  34  to align. Mating of the magnetic coupling  34  of the retrieval device  30  and the indwelling device  10  via coupler  22  may provide sufficient force when each are magnetically linked to allow for the removal of the indwelling device without separating. In many applications it may be desirable to minimize the size of the tether  16  and the magnetic coupler  22  on the indwelling device  10 . For this reason the separation force is relatively low, and perhaps inadequate to allow for removal of the indwelling device  10 . When minimization of the size of the tether  16  and magnetic coupler  22  is desirable, as it is in the urethral application, there is a need to grasp the magnetic coupler  22  to assure adequate gripping to allow removal to be facilitated. To provide much greater security in the retrieval process, basket  40  provides for the entrapment of magnetic coupler  22 . When the retrieval device  30  is withdrawn, if the magnetic coupler  22  and the magnetic coupling  34  separate, the magnetic field will keep magnetic coupler  34  aligned with the magnetic coupling  34  axis, even though it is separated. The tension caused by the tether  16  on the indwelling device, and the magnetic field in the distal direction causes the magnetic coupler  22  to move toward proximal extremity  44  of basket  40 . The proximal extremity  44  of basket  40  is preferably parabolic at the proximal extremity. The magnetic coupler  22  is then entrapped in basket  40 . Withdrawal of retrieval device  30  causes indwelling device  10  to be pulled from the remote location. 
       FIG. 2A  illustrates a sectional view of basket  40  with magnetic coupler  22  entrapment within basket  40  at proximal extremity  44 . Basket members  42  converge at proximal extremity  44  and distally in magnet housing  46 . The plurality of basket members  42  may be comprised of either three, or four, or more members depending upon the application. The preferred quantity is four in the male intraurethral application. Each of the basket members  42  are preferably formed of 0.008 inch diameter round wire made of 304V stainless steel. The individual basket members  42  are located evenly spaced around the perimeter according to their number. In the preferred embodiment a quantity of four basket members  42  are spaced orbitally, 90 degrees apart. Each of the basket members is covered by PTFE (teflon) tubing 0.010 inches in inner diameter and 0.022 inches outer diameter. 
     Another feature of the device of  FIG. 2  is that rotation of retrieval device  30  further causes the tether  16  to pull the magnetic coupler  22  into the proximal extremity  44  of basket  40 . This gives further securing prior to removal of the retrieval device  30  and indwelling device  10 . 
     Yet another useful feature selectively incorporatable within all the embodiments is audible coupling feedback. When coupling of retrieval device  30  occurs, magnetic coupling  34  and magnetic coupler  22  produce a instantaneous acoustical vibration. This vibration is audible when indwelling device  10  is in an environment which does not excessively dampen sound. If the indwelling device  10  and retrieval device  30  are in a severe sound or vibration dampening environment, sound amplification may be necessary to detect the coupling event. The device of the first embodiment is provided with a passageway  50  within elongate member  36 . Hub  70  is provided in the form of a female luer fitting. When audible feedback confirming connection is desired hub  70  is than connected to female luer fitting  60  which provides the acoustical conduit to tube  62 . Amplification device  64  is further interfaced at the distal end  63  of tube  62 . Upon coupling, magnetic coupling  34  with magnetic coupler  22 , sound is generated. The sound waves are transmitted distally through elongate member  36  toward distal extremity  48 . Sound waves continue to travel, entering female luer fitting  60  through tube  62 , to amplification device  64 . A stethoscope is the preferred amplification device. It is obvious to those skilled in the art that amplification device  64  may be accomplished by functionally equivalent devices to that of a stethoscope. Once sound waves impinge upon device  64 , the signal may be filtered, amplified, either in analog or digital format, and manipulated in ways to provide audible, optical, or other sensory outputs. The sound may be transmitted either through a hollow, or solid, or liquid transmission medium. Alternatively, amplification device  64  may be located at any location distal of the distal face of magnetic coupler  22 . 
     When greater amplification is needed than a level that is audibly discernible by a standard stethoscope to detect the coupling, an amplified stethoscope provides for those requirements. Amplified stethoscopes further provide band pass sound filtration capabilities which allow for the removal of frequencies which are outside the sound frequency band of the coupling event. Interface to standard single or dual tube stethoscopes is easily achieved by inserting either a single or “Y” barbed luer into the stethoscope tubing and inserting the opposite barbed fitting into tube  62 . This apparatus and method of sound detection of the coupling event is effective in each of the embodiments described in  FIGS. 2-5 . 
     Referring to  FIGS. 3 and 3A , the second embodiment of the retrieval device of the subject invention functions in similar manner as the device of  FIG. 2 . Although the retrieval device  130  is provided with a basket  132  which is used in retrieval, the device of this second embodiment provides for axial and radial movement of basket  132 . The sequence of mating magnetic coupling  134  with magnetic coupler  22  is identical to that of the first embodiment.  FIG. 3A  illustrates that upon the mating being accomplished, basket  132  is moved relatively toward distal extremity  150  along the longitudinal axis of first elongate member  144  by securing first elongate member  144  and retracting second elongate member  146 . This results in the securing of magnetic coupler  22  within basket  132 . The relative movement is evidenced by the difference in spacing magnitude of gap  188  on  FIG. 3 , and gap  188 ′ on  FIG. 3A . 
     Though the mating of magnetic coupling  134  of the retrieval device  130  and the magnetic coupler  22  of remote device  10  may provide sufficient force when they are magnetically linked to allow for the removal of the remote device without separating, basket  132  is the primary retrieval structure. Like the first and second embodiments, when the retrieval tool  130  is withdrawn, if the magnetic coupler  22  and the magnetic coupling  134  separate, the magnetic field will keep magnetic coupler  22  aligned with the magnetic coupling  134  axis, even though it is separated. The tension caused by the tether  16  on the remote device  10 , and the magnetic field in the distal direction causes the magnetic coupler  22  to move toward proximal extremity  184  of basket  132 . The proximal extremity  184  of basket  132  is radiused at the proximal extremity  184 . The magnetic coupler  22  is then entrapped in the basket  132 . Withdrawal of retrieval device  130  causes remote device  10  to be pulled from the remote location. 
     Another common feature of the device of  FIG. 3  with that of  FIG. 2 , is that rotation of retrieval tool  130  further causes the tether to pull the magnetic coupler  22  into the proximal extremity  184  of basket  132 . This offers further security prior to removal of the retrieval tool  130  and remote device  10 . 
     Referring to  FIGS. 4 and 4A , retrieval device  230  of this embodiment functions in similar manner as the devices of the previous embodiments. The retrieval device  230  is provided with a basket  232  which allows and enables the retrieval or remote device  10 . The device of this third embodiment provides for axial and radial movement of basket  232 . The retrieval device  230  of this embodiment utilizes radial closure of the basket  232 . 
     The distal termination  252  of basket  232  is on first elongate member  244 . When second elongate member  246  is displaced towards proximal extremity  284 , while first elongate member  244  is held stationary, collet ring  248  forces radially-inward basket  232 .  FIG. 4A  illustrates the basket members  256  in the uncompressed position and  FIG. 4A  illustrates the basket members  256  in the compressed position. Gap  288  of  FIG. 4  and gap  288 ′  FIG. 4A  illustrate the relative movement at inner hub  270  and outer hub  272 . As illustrated, the basket  232  deforms radially as the distal termination  252  of basket  232  is forced beneath collet ring  248 . The magnetic coupler  22  is retained within basket  232 . In like manner with the previous two embodiments, though the magnetic coupling  234  of the retrieval device  230  and the remote device mating may provide sufficient force when they are magnetically linked to allow for the removal of the remote device without separating, basket  232  is the primary retrieval mechanism. Like the first and second embodiments, when the retrieval tool  230  is withdrawn, if the magnetic coupler  22  and the magnetic coupling  234  separate, the magnetic field will keep magnetic coupler  234  aligned with the magnetic coupling  234  axis, even though it is separated. The tension caused by the tether  16  on the remote device  10 , and the magnetic field in the distal direction causes the magnetic coupler  22  to move toward proximal extremity  244  of basket  232 . The proximal extremity  244  of basket  232  is radiused at the proximal extremity. The magnetic coupler  22  is then entrapped in the basket. Withdrawal of retrieval device  230  causes remote device  10  to be pulled from the remote location. 
     Another common feature of the device of  FIG. 4  with that of  FIGS. 2 &amp; 3 , is that rotation of retrieval tool  230  further causes the tether to pull the magnetic coupler  22  into the proximal extremity  244  of basket  232 . This offers further security prior to removal of the retrieval tool  230  and remote device  10 . 
       FIGS. 5 ,  5 A and  5 B illustrate a fourth embodiment of the subject invention. The sequence of mating of magnetic coupling  334  with magnetic coupler  22  is identical to that of the previous embodiment. Upon the mating being accomplished, distal inner hub  370  is moved in the distal extremity  350  relative to distal outer hub  372 . First elongate member  344  is secured near the distal extremity  350  to distal inner hub  370  and near the proximal extremity to magnetic coupling  334 . Strap(s)  336  are comprised of silk 1/0 suture which are flexible and strong and extend from distal termination  368  to proximal termination  366 . When distal inner hub  370  is moved in the direction of distal extremity  350  relative to distal outer hub  372 , magnetic coupling  334  enables passage of magnet  18  of retrieval device  10  into passageway  374  of second elongate member  346 . When this movement occurs the strap(s)  336  are placed in tension by the relative movement of the distal termination  368  while proximal termination point  366  remains fixed. 
       FIG. 5   a  illustrates the containment of magnetic coupler  22  within passageway  374  of second elongate member  346  of retrieval device  330 . The proximal end  364  of second elongate member  346  is deflected toward the direction of distal extremity  350 . Retraction of proximal extremity  364  of second elongate member  346  results in its deflection and closure.  FIG. 5   b  illustrates a partial view along line A-A. A recess  380  projects around at least a portion of the perimeter. Tether  16  is secured to magnetic coupler  22  which is encapsulated within second elongate member  346  and extends out of proximal extremity  364  through recess  380 . When retrieval device  330  is withdrawn in a manner consistent with the all embodiments, proximal extremity  364  retains magnetic coupler  22  in place when distal inner hub  370  is manually or mechanically maintained in the direction towards distal extremity  350  relative to distal outer hub  372 . 
     This invention disclosure provides device configurations which achieve this function and method. There are other variations of this invention which will become obvious to those skilled in the art. It will be understood that this disclosure, in many respects, is only illustrative. Changes may be made in details, particularly in matters of shape, size, material, and arrangement of parts without exceeding the scope of the invention. Accordingly, the scope of the invention is as defined in the language of the appended claim.