Patent Description:
The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.

During ureteroscopy or percutaneous nephrolithotomy (PCNL) procedures, baskets are often employed to capture and retrieve stone fragments from a patient's anatomy. After the stone fragments have been removed from the patient and released from the basket, the basket is re-inserted one or more times into the patient's anatomy to remove all or most of the remaining stone fragments. In some instances, however, stone fragments that are too large are captured in the basket, which may result in the basket getting stuck in the ureter or access sheath. If the basket can be pushed back, some fragments can be released and the basket can then be pulled out of the patient. If the basket is completely stuck, the basket can be cut apart from the basket handle and sheath, or a small laser fiber may be inserted into the patient so that laser energy can be utilized to break up the stone fragments. In any case, if the basket is damaged, a new basket has to be employed to complete the medical procedure, which may increase the surgical time and costs.

Among the literature that can pertain to this technology include the following patent documents and published patent applications: <CIT>, <CIT>, <CIT>, <CIT>, <CIT> and <CIT>.

Accordingly, to reduce surgical cost and time, there is a need for a stone retrieval device that prevents the basket from getting stuck in the ureter to minimize trauma to the ureter during retrieval of stone fragments.

It is an object of the present invention to provide an improved medical device for capturing one or more stone fragments. This object is solved by the subject-matter of independent claim <NUM>. Further advantages and preferred embodiments of the invention become apparent from the dependent claims, the description and the accompanying drawings.

In one exemplary aspect, a stone retrieval device includes a sheath and a stone retrieval basket that includes a distal region with a plurality of basket wires and a proximal region with one or more core wires. The stone retrieval basket is contained within the sheath having a distal opening and is movable out the distal opening of the sheath to cause the plurality of basket wires to open into a basket shape. The stone retrieval device further includes a locking mechanism that is engageable to lock the position of the stone retrieval basket with respect to the position of the sheath and a basket force controller that includes a first control stage and a second control stage. The first control stage includes a sensor for measuring force on the stone retrieval basket when the lock mechanism is in an unlocked position, and the second control stage includes a sensor for measuring force on the stone retrieval basket when the lock mechanism is in a locked position.

The stone retrieval device may be further characterized by one or any combination of the features described herein, such as, for example: the lock mechanism is a ratchet mechanism; the ratchet mechanism includes a first protrusion associated with a first member and a set of notches associated with a second member, the first member being contained in the second member and movable relative to the second member, the first protrusion being engaged with one notch of the set of notches when the lock mechanism is in the locked position; the one or more core wires is attached to a third member contained in the first member, the third member being movable relative to the first member and including a second protrusion, the second protrusion being engaged with the first protrusion when the lock mechanism is in the locked position; movement of the third member relative to the first member pulls the plurality of basket wires into the distal opening of the sheath; the first control stage sensor is a visual indicator with a first color; the second control stage sensor is a visual indicator with a second color that is different than the first color; at least one of the sensors of the first control stage and the second control stage is a pop-up flag; at least one of the sensors of the first control stage and the second control stage is a tactile sensor; at least one of the sensors of the first control stage and the second control stage is a sonic sensor; the stone retrieval device further includes an automatic release mechanism that releases the stone retrieval basket when the force on the stone retrieval basket exceeds a predetermined maximum force; and the automatic release mechanism is resettable after releasing the stone retrieval basket.

As an example not covered by the scope of the invention, the present disclosure also provides a method of determining a force on a stone retrieval basket including one or more of the following steps: capturing a stone with the stone retrieval basket; and utilizing a sensor to determine if the force on the stone retrieval basket exceeds a predetermined maximum force. The method may be further characterized by one or any combination of the features described herein, such as, for example: the sensor is visual sensor; and the method further includes releasing the stone retrieval basket when the force on the stone retrieval basket exceeds the predetermined maximum force.

Further features, advantages, and areas of applicability will become apparent from the description provided herein.

Moreover, in the figures, like reference numerals designate corresponding parts throughout the views. In the drawings:.

Referring now to the drawings, a stone retrieval device embodying the principles of the present invention is illustrated in <FIG> and designated at <NUM>. The stone retrieval device <NUM> includes a housing <NUM>, a first member <NUM> contained within a space <NUM> of the housing <NUM>, a second member <NUM> contained within a space <NUM> the first member <NUM>, and a third member <NUM> contained within a space <NUM> the second member <NUM>. The third member <NUM> includes an enlarged portion <NUM> and a smaller portion <NUM>.

The third member <NUM> is able to slide back and forth within the second member <NUM>, and a protrusion <NUM> embedded in the enlarged portion <NUM> selectively engages with a protrusion <NUM> embedded in the second member <NUM>. A biasing member <NUM>, such as, for example, a coiled spring, is positioned about the smaller portion <NUM>. The biasing member <NUM> is arranged to urge the third member <NUM> away from an opening <NUM> of the second member <NUM>.

The second member <NUM> is arranged to slide back and forth within the space <NUM> of the first member <NUM>. The protrusion <NUM> extends outwardly from the second member <NUM> such that the protrusion <NUM> selectively engages with a notch of a set of notches <NUM> located on an inner surface of the first member <NUM>. Hence, engagement of the protrusion <NUM> with the protrusion <NUM> and engagement of the protrusion <NUM> with one of the notches of the set of notches <NUM> operates as a ratchet or locking mechanism to lock the position of the third member <NUM> and the second member <NUM> relative to the first member <NUM> in a locked position. When the protrusion <NUM> is unengaged with any of the notches of the set of notches <NUM>. The second member <NUM>, and consequently, the third member <NUM>, are in an unlocked position relative to the first member <NUM>.

A positioner <NUM> includes an extension <NUM> that extends through an opening <NUM> of the housing <NUM> and an opening <NUM> of the first member <NUM>. The extension <NUM> is attached to the second member <NUM>. An operator of the stone retrieval device <NUM>, such as a physician, can therefore place, for example, a thumb on an indentation <NUM> of the positioner <NUM> and push or pull on the positioner <NUM> to move the second member <NUM> relative to the first member <NUM> and the housing <NUM>.

In certain arrangements, the stone retrieval device <NUM> includes a sensor such as, for example, a pull-force sensor with an opening <NUM> associated with the housing <NUM> and a set of color indicators <NUM> embedded in an enlarged portion <NUM> of the first member <NUM> that the operator can view through the opening <NUM>. Accordingly, as the first member <NUM> slides within the space <NUM> of the housing <NUM>. Different colored indicators of the set of indicators <NUM> are observed through the opening <NUM>. Another biasing member such as, for example, a coiled spring <NUM> is positioned about an extension <NUM> that extends from the enlarged portion <NUM> of the first member <NUM>. The biasing member <NUM> is arranged to urge the first member <NUM> away from an opening <NUM> of the housing <NUM>.

In various arrangements, the stone retrieval device is attached or connected to a capturing device <NUM>, which is shown in greater detail in <FIG>. The capturing device <NUM>, further a capturing basket <NUM>, is positioned within the sheath <NUM> and an optional expandable cone <NUM>. The capturing basket <NUM> includes a rod or wire <NUM> with a distal end <NUM> and a proximal end <NUM> attached to the smaller portion <NUM> of the first member <NUM>. A pair of wires <NUM> and <NUM> are attached to the distal end <NUM> of the rod or wire <NUM>. Specifically, the ends of each of the wires <NUM> and <NUM> are attached to the distal end <NUM> such that the mid region of the wires <NUM> and <NUM> intersect at the distal most end of the capturing basket <NUM>. As shown in <FIG>, the wires <NUM> and <NUM> are generally orthogonal to each other at the distal point of intersection for this particular arrangement. It is contemplated that various alternative basket wire configurations would work with the retraction force sensing handle portion of the present invention.

In addition to surrounding the rod or wire <NUM>, the proximal region of the sheath <NUM> extends through the opening <NUM> of the housing <NUM>, surrounds the extension <NUM> and is positioned within the coiled spring <NUM>. The sheath <NUM> is attached or connected to the enlarged portion <NUM> of the first member <NUM>. Thus, movement of the third member <NUM> relative to the first member <NUM> results in movement of the rod or wire <NUM> relative to the sheath <NUM>. Different color indicators of the set of color indicators <NUM> viewed through the opening <NUM> indicates the pull force on the capturing basket <NUM>. Rather than color indicators, the pull-force sensor can be a sonic sensor, a tactile sensor, a pop-up flag or any other suitable sensor that indicates the pull force on the capturing basket <NUM>.

When the capturing device <NUM> includes the optional cone <NUM>, the capturing basket <NUM> is initially collapsed within the cone <NUM> as the capturing device <NUM> is inserted into an anatomical region of a patient. After the capturing basket <NUM> and the cone <NUM> have been positioned in the anatomical region containing stone fragments, the operator of the stone retrieval device <NUM> pushes on the positioner <NUM> distally such that the wires <NUM> and <NUM> exit a distal end <NUM> of the expandable cone <NUM>. It is contemplated that capturing basket <NUM> may alternatively extend from a sheath without a cone extending therefrom at a distal end. It is contemplated that a distal end of sheath may have a diameter equal to the diameter of the sheath along its length. After the stone fragments <NUM> have been captured by the wires <NUM> and <NUM>, the operator pulls on the positioner <NUM> proximally to draw the stone fragments <NUM> into the cone <NUM>, which causes the cone <NUM> to expand. The distal end <NUM> of the cone <NUM> is configured to expand to a maximum predetermined size.

As the operator of the stone retrieval device <NUM> pulls the positioner <NUM> distally, the second member <NUM> moves proximally relative to the first member <NUM> such that the protrusion <NUM> eventually engages with one of the notches of the set of notches <NUM> associated the first member <NUM>. Further, the proximal movement of the second member <NUM> also results in movement of the second member <NUM> relative to the third member <NUM>. Such movement results in engagement of the protrusion <NUM> with the protrusion <NUM> embedded in the third member <NUM> and compression of the coiled spring <NUM>. As described earlier, engagement of the protrusion <NUM> with the protrusion <NUM> and with one of the notches of the set of notches <NUM> locks the third member <NUM> and the second member <NUM> with the first member <NUM> in a locked position (<FIG>). To unlock the members, the operator pushes on the positioner <NUM> such that the protrusion <NUM> becomes unlocked from the set of notches <NUM> and the coiled spring <NUM> pushes the third member <NUM> proximally relative to the second member <NUM> to unengage the protrusion <NUM> from the protrusion <NUM>.

During the stone removal procedure, the operator can view the color indicators <NUM> through the opening <NUM>. A first color indicator, such as a light color, can indicate to the operator that the pull force on the stone fragments <NUM> will not cause trauma or damage to the patient's ureter. As the operator pulls on the housing <NUM> when the stone retrieval device is in the locked positions, the operator continues to view the color indicators <NUM> through the opening <NUM>. Additional pull force moves the first member <NUM> distally relative to the housing <NUM>, resulting in compression of the coiled spring <NUM> and movement of the set of color indicators <NUM> relative to the opening <NUM>. A second color indicator, such as a darker color, may serve as a warning to the operator that the pull force on the stone fragments is approaching a maximum limit. A third color indicator, such as a darkest color of the set of color indicators, may indicate to the operator that the pulls force is at the maximum limit and any additional pull force may damage the patient's ureter. Reducing the pull force results in the coiled spring <NUM> pushing the first member <NUM> proximally relative to the housing <NUM> such that the lighter colored indicators of the set of indicators <NUM> are viewed through the opening <NUM> to indicate to the operator that the pull force on the capturing basket <NUM> has been reduced to a desired level.

A stone retrieval device may comprise: a sheath; a stone retrieval basket including a distal region with a plurality of basket wires and a proximal region with one or more core wires, the stone retrieval basket being contained within the sheath and movable out of a distal opening of the sheath to cause the plurality of basket wires to open into a basket shape; a lock mechanism for locking the position of the stone retrieval basket with respect to the position of the sheath; and a basket force controller including a first control stage and a second control stage, wherein the first control stage includes a sensor for measuring force on the stone retrieval basket when the lock mechanism is in an unlocked position and the second control stage includes a sensor for measuring force on the stone retrieval basket when the lock mechanism is in a locked position.

The lock mechanism may be a ratchet mechanism. In particular wherein the ratchet mechanism may include a first protrusion associated with a first member and a set of notches associated with a second member, the first member being contained in the second member and movable relative to the second member, the first protrusion being engaged with one notch of the set of notches when the lock mechanism is in the locked position. Especially wherein the one or more core wires may be attached to a third member contained in the first member, the third member being movable relative to the first member and including a second protrusion, the second protrusion being engaged with the first protrusion when the lock mechanism is in the locked position. Preferably wherein movement of the third member relative to the first member pulls the plurality of basket wires into the distal opening of the sheath.

The first control stage sensor may be a visual indicator with a first color. In particular wherein the second control stage sensor may be a visual indicator with a second color that is different than the first color.

At least one of the sensors of the first control stage and the second control stage may be a pop-up flag.

At least one of the sensors of the first control stage and the second control stage may be a tactile sensor.

At least one of the sensors of the first control stage and the second control stage may be a sonic sensor.

The stone retrieval device may further comprise an automatic release mechanism that releases the stone retrieval basket when the force on the stone retrieval basket exceeds a predetermined maximum force. In particular wherein the automatic release mechanism may be resettable after releasing the stone retrieval basket.

A method of determining a force on a stone retrieval basket may comprise: capturing a stone with the stone retrieval basket; and utilizing a sensor to determine if the force on the stone retrieval basket exceeds a predetermined maximum force.

Claim 1:
A stone retrieval device (<NUM>) comprising:
a sheath (<NUM>) having a distal opening;
a stone retrieval basket (<NUM>) movable with respect to the sheath (<NUM>) and configured to capture a stone (<NUM>);
a force sensor configured to measure a force on the stone retrieval basket (<NUM>), the force sensor including an indicator (<NUM>) which indicates whether the force on the stone retrieval basket (<NUM>) traverses a threshold force; and
a locking mechanism that is engageable to lock a position of the stone retrieval basket (<NUM>) relative to the sheath (<NUM>), wherein the locking mechanism includes:
a set of notches (<NUM>) associated with a first member (<NUM>);
a first protrusion (<NUM>) associated with a second member (<NUM>), wherein the second member (<NUM>) is movable relative to the first member (<NUM>); and
a third member (<NUM>) coupled to the stone retrieval basket, the third member being movable relative to the first member (<NUM>) and including a second protrusion (<NUM>),
wherein in the locked position the first protrusion (<NUM>) is engaged with a notch of the set of notches (<NUM>) and the second protrusion (<NUM>) is engaged with the first protrusion (<NUM>).