Patent Description:
In order to provide desirable pushability and trackability for these small-bore sample-collection needles, and to prevent inadvertent (e.g., early and/or late) collection of tissue in one or more distal needle openings, a stylet is typically provided through the length of the needle lumen. After the distal end opening(s) of the needle is/are directed to a target location via a medical endoscope such as a bronchoscope, an EUS endoscope, a duodenoscope, or other minimally-invasive endoscope device, the stylet is withdrawn and a syringe or other modality is attached to the proximal needle end for generating vacuum through the needle lumen to facilitate sample collection by drawing sample material into the distal end opening(s) of the needle. Stylet-management may pose challenges during such procedures.

Specifically, traditional stylets are often nearly <NUM> meters in length and must be handled by an operator, such as a nurse, after removal. These stylets are not sterile after having been in a patient. Further, multiple passes may be taken may be taken by an endoscopist before removing the needle, and some endoscopists use a fanning technique to take a sample from several different areas of a target area. With current designs, the endoscopist may not be able to tell if the needle is blocked by core tissue, therefore rendering additional maneuvering pointless. Continued maneuvering also tends to wear out the tip of the needle, reducing its effectiveness and decreasing the quality of the collected sample. Because an endoscopist has no visual confirmation that a sample has collected, the device may be removed without having collected a tissue sample at all. Further, the use of a traditional stylet can create a number of time consuming tasks including feeding the stylet into a cannula during sample retrieval in procedures that may require multiple introductions and retractions of a stylet from a cannula lumen (e.g., placing the stylet in the lumen for navigation then removing it to allow pulling a vacuum through the lumen with a syringe or other vacuum source).

Thus, it may be desirable to provide a stylet apparatus that will provide feedback to an endoscopist that a sample is being collected, indicate when the stylet apparatus is blocked, reduce the amount of manipulation and time needed during sample collection, and improve the quality of the collected samples. <CIT> describes a disposable endometrial biopsy device comprising an elongated blunt-end catheter with distally placed tissue acquisition side-hole and proximally attached aspiration syringe with spring-loaded plunger having latching mechanism to release plunger for induction of aspiration.

A liquid stylet apparatus is provided. In certain embodiments, the liquid stylet apparatus comprises a tube with a transparent portion and at least partially filled with a liquid, a powering device in fluid communication with the tube, a catheter located distally of the tube and in fluid communication with the tube, wherein the catheter is at least partially filled with the liquid, a collection device located distally of the catheter and in fluid communication with the catheter, wherein the collection device is configured to engage a target area of a patient, and an indicator contacting the liquid and located at least partially within the tube, wherein the position of the indicator within the tube is visible through the transparent portion. The liquid stylet apparatus may further comprise a valve for controlling the flow of the liquid between the tube and the catheter.

In another embodiment, the liquid stylet apparatus comprises a valve member with a channel. A first state may be provided wherein fluid communication between the tube and the catheter is provided through the channel. Further, a second state may be provided wherein the valve member seals the tube from the catheter, thereby preventing fluid communication through the channel. The channel may be in fluid communication with a vacuum chamber or outside in the second state. The liquid stylet apparatus may further comprise a third state wherein the tube is in fluid communication with the catheter through the channel, and wherein the indicator comprises an air bubble.

Some embodiments of the liquid stylet apparatus may include graduations (i.e., visual indicia on and/or in the device structure) configured to provide a visual indication of the location of the indicator in a manner directly corresponding to a distal location/ position of the liquid so that a user can readily ascertain the longitudinal movement of the liquid functioning as a stylet. Further, the liquid stylet apparatus may have a powering device configured to form a vacuum for drawing the liquid into the tube. A valve for controlling the flow of the liquid between the tube and the catheter may also be provided.

Various embodiments are described below with reference to the drawings, in which like elements generally are referred to by like numerals. The relationships and function(s) of the various elements of the embodiments may better be understood by reference to the following detailed description. However, embodiments are not limited to those illustrated in the drawings. It should be understood that the drawings are not necessarily to scale, and in certain instances details may have been omitted that are not necessary for an understanding of embodiments disclosed herein, such as-for example-conventional fabrication and assembly.

The invention is defined by the claims, may be embodied in many different forms, and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey enabling disclosure to those skilled in the art. Any methods disclosed hereinafter do not form part of the scope of the invention, and are mentioned for illustrative purposes only. As used in this specification and the claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. The terms "proximal" and "distal" are used herein in the common usage sense where they refer respectively to a handle/doctor-end of a device or related object and a tool/patient-end of a device or related object. The term "about" when used with reference to any volume, dimension, proportion, or other quantitative value is intended to communicate a definite and identifiable value within the standard parameters that would be understood by one of skill in the art (equivalent to a medical device engineer with experience in the field of tissue devices and/or pressure/vacuum-exertion and monitoring devices), and should be interpreted to include at least any legal equivalents, minor but functionally-insignificant variants, and including at least mathematically significant figures.

A liquid stylet apparatus is herein described which may be used for the performance of sample collection (e.g., FNA, FNB) technique. The liquid stylet apparatus may vary from a needle stylet using an FNA or FNB needle, for example as described by <CIT> and <CIT>.

As described herein, a liquid stylet apparatus may be a device primed with liquid before use. The liquid may be any suitable liquid, and for example may comprise a saline solution, such as a saline solution with a concentration of <NUM>% w/v of NaCl in water. The liquid stylet apparatus may operate when the liquid is withdrawn from a catheter. Those of skill in the art familiar with basic principles of hydraulics will appreciate that the liquid works to transfer a power or force to the distal end of the catheter, which distal end may be attached to a needle or another collection device for collecting a sample of tissue. The power or force is then provided at the collection device (such as a needle), which may operate to draw or aspirate a tissue sample into the distal end of a lumen. The sample may later be ejected from the lumen and retrieved by applying a force to the liquid in the distal direction after the collection device is removed from the patient.

The liquid stylet apparatus described herein provides several advantages. For example, the liquid stylet apparatus as described provides direct feedback to a user (e.g., an endoscopist) of the operation of the device, thereby providing an indication of whether or not a tissue sample has been collected or if the device is blocked or restricted. This feedback allows the user to improve his or her collection technique (e.g., reduce the amount of fanning), which can improve the effectiveness of the collection procedure and reduce patient complications. The assurance provided by the feedback can also reduce the amount of time and the number of steps taken by the user, which reduces the wear of components (e.g., blunting of the tip of a needle) and may reduce patient complications. These reductions may result in a lower overall cost to the patient.

A high degree of control over the collection procedure may also be provided by the present embodiments. For example, precise adjustments to the valves and/or the powering devices described herein may give precise control over the power or force provided at the point of contact between the collection device and the target area. Using the present embodiments also simplifies retrieval and flushing processes, as the liquid already within the apparatus may be forced distally to flush the components of the apparatus and/or eject a collected tissue sample.

<FIG> illustrates one embodiment of a liquid stylet apparatus <NUM>. Liquid stylet apparatus <NUM> comprises a powering device <NUM> located proximally of a tube <NUM>. In this embodiment, powering device <NUM> is illustrated as a syringe, but other embodiments may use another device known in the art for generating/pulling a vacuum in a controllable manner (e.g., pump bulb, powered vacuum source, etc.). Tube <NUM> may be at least partially transparent to provide a visual indication of the position of objects therewithin. A housing <NUM> surrounds the tube <NUM>. Housing <NUM> may have a viewport <NUM> configured to provide a line-of-sight to tube <NUM> for visualization of the indicator <NUM> therewithin, including movement of the indicator <NUM> relative to the tube <NUM> and the housing <NUM>. Housing <NUM> may further include graduations <NUM> for precisely determining the position of objects within tube <NUM> and for measuring motion of those objects relative to the tube and/or housing (e.g., as visual indicia of movement of fluid within tube <NUM> at a more distal location). Alternatively or additionally, graduations <NUM> may be located directly on tube <NUM> or in another suitable location. A first valve <NUM> is located between the powering device <NUM> and the tube <NUM>. The first valve <NUM> may be adapted to control fluid communication between powering device <NUM> and tube <NUM>. A catheter <NUM> is located distally of tube <NUM>. The liquid stylet apparatus <NUM> additionally includes a second valve <NUM> located distally of tube <NUM> and proximally of the catheter <NUM>. Second valve <NUM> may be a bubble valve, described in further detail below, and is preferably configured to control the passage of fluid between catheter <NUM> and tube <NUM>.

During normal operation, a collection device <NUM>, which may be a needle (see <FIG>) coupled to the distal end of catheter <NUM>, is inserted into a patient body and directed to a target tissue <NUM>, where it preferably engages a target tissue sample <NUM>'. Powering device <NUM> may work to withdraw liquid <NUM> from catheter <NUM> and into tube <NUM>. The incompressible nature of liquid <NUM> causes the power to instantaneously transfer through a fluid flow path defined by catheter <NUM> to collection device <NUM>. During operation, an indicator <NUM> may be viewable within tube <NUM>. The position of indicator <NUM> within tube <NUM> provides a user with a visual indication of the operation of the liquid stylet apparatus <NUM>. For example, if liquid stylet apparatus <NUM> is obstructed, liquid <NUM> will not draw from catheter <NUM>, and therefore indicator <NUM> will not move within tube <NUM>. When liquid stylet apparatus <NUM> operates properly, liquid <NUM> (and indicator <NUM>) will draw in the proximal direction in a predictable manner readily determined in keeping with the knowledge of those skilled in the art (given specific dimensions of the device's construction).

To better illustrate the operation of liquid stylet apparatus <NUM>, <FIG> are provided, illustrating a method of use. <FIG> depicts the liquid stylet apparatus <NUM> in a first state, where collection device <NUM> engages a target area (e.g., tissue sample <NUM>), but a substantial amount of the sample has not yet been collected. Indicator <NUM>, which may be a bubble of fluid or other object distinct from liquid <NUM> as described below, is located near the proximal end of the viewable portion of tube <NUM>. Powering device <NUM> is shown in <FIG> as not yet providing a vacuum (or first valve <NUM> is closed). Liquid <NUM> substantially fills collection device <NUM> and may also substantially fill catheter <NUM> and at least a proximal portion of tube <NUM>. First valve <NUM> and second valve <NUM> may be opened or closed.

<FIG> depicts liquid stylet apparatus <NUM> in a second state. Here, the powering device <NUM> operates or has operated to create a vacuum, thereby drawing liquid <NUM> in the proximal direction. First valve <NUM> is open for at least a period of time during the transition from the first state to the second state to allow the power provided by powering device <NUM> to act on liquid <NUM>. However, first valve <NUM> may be closed at any time to stop movement of liquid <NUM>. When transitioning to the second state, indicator <NUM> moved in the proximal direction within tube <NUM>, and its proximal displacement is clearly indicated through viewport <NUM>. The incompressible nature of liquid <NUM> caused mechanical power to be transferred through catheter <NUM> to collection device <NUM>. As liquid receded from collection device <NUM> and into catheter <NUM>, a vacuum was formed at the distal end of collection device <NUM>, thereby pulling the tissue sample <NUM>' from target area <NUM> into a lumen of the collection device <NUM>. Second valve <NUM> was open for at least a period of time during the transition from the first state to the second state to allow fluid communication between catheter <NUM> and tube <NUM>.

A third state is depicted by <FIG>. Here, powering device <NUM> is depicted as having a plunger extended further in the proximal direction, which represents that a stronger vacuum was formed and used during the transition from the second state to the third state. However, it is noted that first valve <NUM> may simply have opened for an additional period of time, thereby allowing powering device <NUM> to apply power or force to liquid <NUM> for an additional period of time. In any case, during the transition from the second state to the third state, indicator <NUM> moved farther in the proximal direction, indicating that an additional amount of tissue sample <NUM>" has been collected in the fashion described above. Second valve <NUM> was open for at least a period of time during the transition from the second state to the third state to allow fluid communication between catheter <NUM> and tube <NUM>.

Referring to <FIG>, one embodiment of a liquid stylet apparatus <NUM> comprises a handle <NUM>, which may have a distal end coupled to catheter. The catheter is located distally of handle <NUM>. Handle <NUM> may be utilized by an operator during a sample collection procedure, and may provide the operator additional control in locating and engaging a desired area of tissue in a patient's body with a collection device located at the distal end of catheter. Further, handle <NUM> may be configured to communication with technology designed to assist in the guidance of the collection device to a target area in a patient body.

<FIG> shows an embodiment of liquid stylet apparatus <NUM> where a control module <NUM> is separated from handle <NUM> by a hose <NUM>. Control module <NUM> may comprise catheter <NUM>, first valve <NUM>, second valve <NUM>, and a powering device (not shown). Second valve <NUM> may alternatively be positioned anywhere between catheter <NUM> and handle <NUM>, on handle <NUM>, or distally of handle <NUM>. Hose <NUM> may provide fluid communication between control module <NUM> and handle <NUM>. Handle <NUM> is coupled to catheter <NUM>, which is in fluid communication with a collection device at the distal end of the liquid stylet apparatus <NUM>. This embodiment may be advantageous when it is desired that a first operator (e.g., a nurse) operates the control module <NUM> while a second operator (e.g., a physician) operates handle <NUM> to properly locate a target site in a patient. In the illustration of <FIG>, handle <NUM> is a handle of an EUS or other endoscopic biopsy needle (for example, without limitation, of the type described in <CIT>).

<FIG> shows a non-limiting embodiment of a powering device for providing power to a liquid stylet apparatus, here depicted as powering device <NUM>. Powering device <NUM> comprises a plunger <NUM> with a sealing tip <NUM>. Plunger <NUM> is configured to slide within a tube <NUM>. Sealing tip <NUM> may be configured to fit snugly against the inner walls of tube <NUM> such that it forms a fluid seal between the internal portions of tube <NUM> located on opposite sides of sealing tip <NUM>. Powering device <NUM> may further comprise a housing <NUM> with a viewport <NUM> to provide an operator with a visual indication of the location of sealing tip <NUM> within tube <NUM>. Housing <NUM>, plunger <NUM>, and/or tube <NUM> may be graduated to provide precise indications of the operation of the liquid stylet apparatus <NUM>. In this embodiment, plunger <NUM> preferably operates over a range during normal operation such that sealing tip <NUM> is continuously visible through the viewport <NUM>. To operate powering device <NUM>, an operator may provide a force to handle <NUM> in the proximal direction, thereby sliding plunger <NUM> proximally to draw liquid <NUM> into the distal portion of tube <NUM>. This force is transferred through liquid <NUM> to a collection device located at the distal end of liquid stylet apparatus <NUM>. In this embodiment, the movement of plunger <NUM> (and the changing location of sealing tip <NUM>) indicates to an operator that material is being collected by the collection device. When plunger <NUM> will not move or becomes difficult to move, the collection device is likely at least partially blocked.

Referring to <FIG>, the powering device alternatively may be another vacuum forming device, such as loose-piston syringe <NUM>. Syringe <NUM> comprises a syringe body <NUM>, which may be substantially in the form of a hollow tube with an end <NUM> including opening <NUM>. Opening <NUM> is preferably configured to communicate with equipment located distally of a powering device, as described herein. Syringe <NUM> further comprises a plunger <NUM> that is at least partially contained within syringe body <NUM>. Plunger <NUM> is slidable within syringe body <NUM> and comprises a piston <NUM> configured to fit snugly against the inner walls of syringe body <NUM>. Piston <NUM> preferably forms a fluid seal between the internal portions of syringe body <NUM> located on opposite sides of piston <NUM>. Plunger <NUM> may further include a mechanical stop <NUM>, which is sized to interact with syringe body <NUM> such that it prevents plunger <NUM> from being completely removed from syringe body <NUM> during normal operation. Mechanical stop <NUM> may further be adapted to apply a friction force sufficient to hold plunger <NUM> in place during normal operation even when a vacuum <NUM> is contained within syringe body <NUM>. In the depicted embodiment, plunger <NUM> comprises a handle <NUM> located at the proximal end of plunger <NUM>. An operator may adjust the position of piston <NUM> within the syringe body <NUM> by applying a force to handle <NUM> in either the distal or proximal direction.

While not necessary in all embodiments, syringe <NUM> may comprise a separating piston <NUM> positioned within syringe body <NUM> located distally of plunger <NUM>. Separating piston <NUM> may be formed to fit snugly against the inner walls of syringe body <NUM> to create a fluid seal between internal portions of syringe body <NUM> located on opposite sides of separating piston <NUM>. For example, liquid <NUM> may be substantially sealed from internal portions of syringe body <NUM> located proximally of separating piston <NUM>.

In embodiments that include a separating piston <NUM>, a cavity <NUM> may be formed within syringe body <NUM> between separating piston <NUM> and piston <NUM> during operation. Cavity <NUM> may be formed, for example, when plunger <NUM> moves in the proximal direction. The position of separating piston <NUM>, which corresponds with the amount of liquid <NUM> within the distal end of syringe body <NUM>, may lag behind the position of piston <NUM>. A vacuum <NUM> within cavity <NUM> then applies a proximal force on separating piston <NUM>, which will, in turn, apply a proximal force to liquid <NUM>, thereby creating a tendency to draw additional liquid <NUM> into the distal end of syringe body <NUM>. As described herein, this force is mechanically transferred to a needle located at the distal end of liquid stylet apparatus <NUM>.

Second valve <NUM> (see <FIG>) may be a bubble valve <NUM>, illustrated in detail by <FIG>. Bubble valve <NUM> is preferably configured to control flow (e.g., fluid flow) between a tube <NUM> and a catheter <NUM> and may be positioned distally of tube <NUM> and proximally of catheter <NUM>. The depicted bubble valve <NUM> comprises a housing <NUM> and a valve member <NUM>. Valve member <NUM> may be, but is not limited to, a rotating valve member (as depicted). The valve member <NUM> may be at least partially encompassed by the housing <NUM> and may be configured to rotate with respect to the housing <NUM>. This rotation may be achieved manually by an operator (e.g., through the movement of a handle) or automatically. Bubble valve <NUM>, as depicted, comprises at least an open configuration (i.e., tube <NUM> and catheter <NUM> are in fluid communication) and a closed configuration (i.e., a fluid seal exists between tube <NUM> and catheter <NUM>). Valve member <NUM> preferably comprises a passage or channel <NUM> for the facilitation of the passage of a liquid through bubble valve <NUM> when in the open configuration.

Liquid stylet apparatus <NUM> may comprises a first state, depicted by <FIG>, where bubble valve <NUM> is open (i.e., in the open configuration). The first state may be an initial state, where the distal end of catheter <NUM> and the proximal end of tube <NUM> are primed with liquid <NUM>. Channel <NUM> may also be primed with liquid <NUM> in this first state. During a sample collection procedure, the liquid stylet apparatus <NUM> may be in the first state while an operator moves the collection device (not shown) into engagement with a target sample.

In a second state, depicted by <FIG>, bubble valve <NUM> is in a closed configuration. In the closed configuration, channel <NUM> may be in fluid communication with a chamber <NUM>. Chamber <NUM> may be a vacuum chamber and may be pre-loaded with a vacuum or in communication with an external vacuum source. In the second state, channel <NUM> may substantially align with a first opening <NUM> such that channel <NUM> is in fluid communication with chamber <NUM>. Additionally or alternatively, channel <NUM> may be aligned with a second opening <NUM>, which allows entry of outside air (or another fluid distinct from liquid <NUM>) into channel <NUM>. In the depicted embodiment, channel <NUM> is aligned with both first opening <NUM> and second opening <NUM> simultaneously such that the conditions externally of housing <NUM> adjacent to the two openings are in fluid communication through channel <NUM>. Here, when liquid stylet apparatus <NUM> is adjusted from the first state to the second state, a vacuum in chamber <NUM> operates to draw liquid <NUM> from channel <NUM> into chamber <NUM>, and channel <NUM> fills with outside air.

Liquid stylet apparatus <NUM> may additionally comprise a third state as shown in <FIG>. The third state is achieved when channel <NUM> is filled with air in the second state and then bubble valve <NUM> is moved to the closed configuration. In the third state, the air filling channel <NUM> in the second state defines bubble <NUM> in the third state, which acts as an indicator. Bubble <NUM> is not limited to air in all embodiments, and could alternatively be a defined region of another type of fluid that is distinct from liquid <NUM>. In an exemplary liquid stylet apparatus <NUM> with a bubble valve <NUM>, a liquid <NUM> is chosen with viscosity properties and other physical properties such that bubble <NUM> remains in substantially the same position with respect to the immediately adjacent molecules of liquid <NUM>. In the third state, valve member <NUM> seals the openings <NUM> and <NUM> to prevent bubble <NUM> or liquid <NUM> from exiting through either opening. Channel <NUM> is at least partially aligned with catheter <NUM> and tube <NUM> to provide fluid communication among those components for operation of liquid stylet apparatus <NUM>.

Tube <NUM> may be transparent or may comprise a transparent section such that the position of bubble <NUM> is viewable. Power may be provided by a powering device (not shown) while liquid stylet apparatus <NUM> is in the third state (or another state in the open configuration), thereby drawing liquid <NUM> from catheter <NUM>, through channel <NUM>, and into tube <NUM>. As liquid <NUM> is drawn out of catheter <NUM>, bubble <NUM> will move a distance precisely corresponding to the amount of liquid <NUM> drawn. As herein described, the motion of bubble <NUM> provides a visual indication of the operation of the device, such as the amount of a tissue sample drawn into a collection device located at the distal end of liquid stylet apparatus <NUM>.

Referring to <FIG>, in some embodiments, the collection device <NUM> of the liquid stylet apparatus may generally be a needle with a lumen in fluid communication with a catheter. Collection device <NUM> comprises a needle <NUM> with a lumen <NUM> therethrough and is in fluid communication with a catheter <NUM> (as depicted by <FIG>). Needle <NUM> may comprise a tip <NUM> at its distal end configured to engage a target tissue area in a patient body by cutting or otherwise collecting a tissue sample <NUM>'. Tip <NUM> may be configured with a sharp tissue-piercing beveled geometry or may otherwise be configured to penetrate and/or cut through tissue.

Collection device <NUM> may comprise a piston <NUM> located at least partially within lumen <NUM>. Piston <NUM> may be moveable proximally and distally within lumen <NUM> and may act as a seal to prevent contact between liquid <NUM> and tissue sample <NUM>'. This may be advantageous in instances when it is preferable to prevent the mixing of liquid <NUM> and tissue sample <NUM>'. Piston <NUM> preferably is located near the distal end of lumen <NUM> when collection device <NUM> is initially inserted into a patient and initially engages a target area. The portion of lumen <NUM> located proximally of piston <NUM> may be substantially filled with liquid <NUM>. When, as described herein, liquid <NUM> is drawn in the proximal direction by a powering device, the force provided from the powering device is mechanically transferred though liquid <NUM> to move piston <NUM> in the proximal direction. A vacuum <NUM> is thereby provided in the section of lumen <NUM> located distally of piston <NUM> to draw in tissue sample <NUM>'. Tissue sample <NUM>' may remain in lumen <NUM> when collection device <NUM> is removed from a patient body. It may then be discarded from the liquid stylet apparatus when a distal force is provided to liquid <NUM>, thereby forcing piston <NUM> to move in the distal direction to eject tissue sample <NUM>'. While it may be advantageous for collection device <NUM> to include a piston <NUM>, collection device <NUM> may be similarly operable without a piston, particularly in situations where there is no concern over contact between liquid <NUM> and tissue sample <NUM>'.

In some embodiments, the liquid stylet apparatus may comprise a pressure transducer or other sensing device to provide feedback to a user. For example, referring to <FIG>, control module <NUM> comprises a pressure transducer <NUM> for measuring the pressure of liquid <NUM> within catheter <NUM>. The pressure transducer <NUM> may be any type of transducer configured to sense the pressure of liquid <NUM> or the strain of catheter <NUM>, for example, a piezoresistive strain gage, a capacitive pressure sensor, or other pressure-sensing device known to those of skill in the art. In some embodiments, a mechanical pressure gauge can be used. Pressure transducer <NUM>, or an alternative sensor, may be placed at any point along a liquid stylet apparatus, but it may be most practical to position pressure transducer <NUM> adjacent to catheter <NUM>, which is generally in fluid communication with a collection device at its distal end and may be in fluid communication with a powering device through lumen <NUM> during operation. Generally, it is most desirable for pressure transducer <NUM> to be positioned to interact with liquid <NUM>, but in some embodiments a sensor may instead be placed interact with a vacuum created in a powering device.

In an exemplary liquid stylet apparatus, pressure transducer <NUM> is connected to a controller <NUM> through wires <NUM>. Controller <NUM> monitors variations in pressure signals from pressure transducer <NUM> and uses pre-programed parameters to verify proper operation of the liquid stylet apparatus. For example, referring to <FIG>, a controller may be configured to provide a signal to an indication light <NUM> that provides an operator with an indication of the device's operation. In one setting, indication light <NUM> provides a "positive" indication (e.g., a green light) when the device is operating properly. When a sufficiently low pressure within liquid <NUM> is sensed, a negative indication (e.g., a red light) may notify a medical professional that catheter <NUM> (see <FIG>) is blocked. A reset button <NUM>, or other user control device, may be included. In other settings, different types of user interfaces may communicate the status of the device to a user. For example, control module <NUM> may include a vibration device or audio device connected to controller <NUM> and configured to respectively vibrate or sound when a certain characteristic is sensed. In other embodiments, feedback from controller <NUM> may be collected and analyzed by advanced data acquisition and analysis equipment to provide sophisticated monitoring and analysis.

Preferably, a user will be able to identify, whether by direct observation (e.g., via touch sense of the user-control surfaces and/or viewing an indicator such as a bubble, bead, or other object that moves with the liquid in the continuous lumen in a manner showing movement of the distal liquid end corresponding to pressure/vacuum in the distal collection device end) and/or by a sensor device (e.g., a pressure transducer or the like with some type of tactile, audible, and/or visual indicia of status) the relative position and/or pressure of the distal sample-collection region within a needle or other collection device. The embodiments described herein, whether used individually, in combination, or with combination of particular features of one or more embodiments, preferably provide a user with the ability to carefully control the vacuum being exerted within a collection device that is distant from the user control surfaces. For example, an endoscopic needle such as a ProCore® needle from Cook Endoscopy may include a tissue-collection distal end that may be about <NUM> up to about <NUM> distal from the control surface(s) and/or indicator (e.g., bubble visible through a viewing window) of embodiments herein described. In certain embodiments this distance may be between about <NUM> and about <NUM>, and in particular embodiments the distance may be about <NUM> to about <NUM>.

Claim 1:
A liquid stylet apparatus (<NUM>) comprising:
a tube (<NUM>) with a transparent portion;
a powering device (<NUM>) in fluid communication with the tube;
a catheter (<NUM>) located distally of the tube and attached in fluid communication with the tube, wherein the catheter is at least partially filled with a liquid (<NUM>) to mechanically transfer force from the powering device;
a collection device (<NUM>) located distally of the catheter and attached in fluid communication with the catheter, wherein the collection device is configured to engage a target area (<NUM>) of a patient; and
characterised by said tube being at least partially filled with said liquid (<NUM>), and an indicator (<NUM>) contacting the liquid and located at least partially within the tube, wherein a position of the indicator within the tube is visible through the transparent portion, wherein the position of the indicator within the tube provides a user with a visual indication of the operation of the liquid stylet apparatus.