Patent Description:
Document US <NUM>/<NUM> A1 relates to a device for the injection of a bone cement. A container is provided with one end including an outlet and a second end that receives a piston. The piston is moved by means of an injection screw that projects from the container body and engages with gripping means comprising injection screw rotation means that can self-lock depending on the pressure exerted inside the container body, said rotation means comprising a handle which is provided with a passage that receives the injection screw and which is hinged thereto by means of a pair of male/female disks. One disk is known as the drive disk and moves integrally with the rotation movements of the handle, while the other disk is known as the driven disk, said drive disk coming into contact with the driven disk in response to a compressive force exerted on the distal part of the injection screw.

Associated methods for operating a curable material dispensing system are also described herein to aid understanding the invention.

According to the present invention, a system for dispensing curable material includes a housing, and a chamber coupled to the housing. The chamber defines a dispensing volume that is adapted to dispense the curable material. A first control surface coupled to the housing and adapted to receive a primary input force from a user. The system includes a locking nut disposed within the housing and includes internal threads. A lead screw is rotatably fixed relative to the first control surface with the lead screw includes a proximal end, a distal end, external threads at least partially disposed between the proximal and distal ends, and a translation axis defined between the proximal and distal ends. Engagement between the external threads of lead screw and the internal threads of the locking nut adapted to provide for movement of the lead screw along the translation axis to compress the curable material within the dispensing volume in response to the first control surface receiving the primary input force in a first direction. A defeatable unidirectional mechanism is operably coupling the first control surface and the housing. The defeatable unidirectional mechanism is adapted to permit for distal advancement of the lead screw in response to the first control surface receiving the primary input force includes a first input torque below a torque threshold, and permit proximal movement of the lead screw with rotation of the first control surface about the translation axis in a second direction opposite the first direction in response to the first control surface receiving a second torque input opposite the first input torque and at least equal to the torque threshold.

In certain exemplary implementations (not claimed), a system for dispensing curable material includes a chamber defining a dispensing volume that is adapted to dispense the curable material through a distal outlet in communication with the dispensing volume. A first control surface is adapted to receive a primary input force from a user, and a lead screw is rotatably fixed relative to the first control surface. The lead screw includes a proximal end, a distal end, external threads at least partially disposed between the proximal and distal ends, and a translation axis defined between the proximal and distal ends. A plunger is coupled to the lead screw with the plunger disposed within the dispensing volume. The plunger is adapted to be advanced distally along the translation axis to compress the curable material within the dispensing volume in response to the first control surface receiving the primary input force. A locking nut includes internal threads threadably engaging the external threads of the lead screw, and an engagement feature. The system also includes an actuator having a second control surface that is adapted to receive a secondary input force from the user to engage the actuator and the engagement feature of the locking nut in an engaged position and disengage the actuator and the engagement feature of the locking nut in a disengaged position. The internal threads of the locking nut and the external threads of the lead screw are configured to provide for rotation of the locking nut about the translation axis when the actuator is in the disengaged position to permit the plunger to move proximally along the translation axis and permit the compressed curable material to at least partially decompress within the dispensing volume.

In certain exemplary implementations (not claimed), a system for dispensing curable material includes a housing, and a chamber coupled to the housing. The chamber defines a dispensing volume that is adapted to dispense the curable material. A first control surface is coupled to the housing and adapted to receive a primary input force from a user. A lead screw is rotatably fixed relative to the first control surface with the lead screw including a proximal end, a distal end, external threads at least partially disposed between the proximal and distal ends, and a translation axis defined between the proximal and distal ends. A plunger is coupled to the distal end of the lead screw. The system includes a locking nut having internal threads threadably engaging the external threads of the lead screw, and an engagement feature. An actuator is coupled to the housing and includes a second control surface. The second control surface is adapted to receive a secondary input force from the user to engage the actuator and the engagement feature of the locking nut in an engaged position and disengage the actuator and the engagement feature of the locking nut in a disengaged position. The locking nut is adapted to be rotatably fixed relative to the housing and prevent rotation of the locking nut about the translation axis when the actuator is in the engaged position such that the internal threads of the locking nut and the external threads of the lead screw provide for distal advancement the lead screw and the plunger along the translation axis to compress the curable material within the dispensing volume in response to the first control surface receiving the primary input force.

In certain exemplary implementations (not claimed), a system for dispensing curable material includes a chamber defining a dispensing volume for dispensing the curable material. A lead screw is rotatably fixed relative to a first control surface with the lead screw includes a proximal end, a distal end, external threads at least partially disposed between the proximal and distal ends, and a translation axis defined between the proximal and distal ends. A locking nut includes internal threads threadably engaging the external threads of the lead screw. The internal threads of the locking nut and the external threads of the lead screw are defined by a screw efficiency of greater than <NUM>% such that the locking nut is adapted to rotate about the translation axis to permit the lead screw to translate proximally along the translation axis in response to proximal forces provided by the compressed curable material within the dispensing volume.

In certain exemplary implementations (not claimed), a system for dispensing curable material includes a chamber defining a dispensing volume adapted to dispense the curable material. A first control surface is adapted to receive a primary input force from a user. A lead screw is rotatably fixed relative to the first control surface. The lead screw includes a proximal end, a distal end, external threads at least partially disposed between the proximal and distal ends, and a translation axis defined between the proximal and distal ends. The lead screw is adapted to be advanced distally along the translation axis to compress the curable material within the dispensing volume in response to the first control surface receiving the primary input force. A locking nut includes internal threads threadably engaging the external threads of the lead screw. The internal threads of the locking nut and the external threads of the lead screw are configured to provide for rotation of the locking nut about the translation axis in response to the lead screw translating proximally without rotation along the translation axis to permit the compressed curable material to at least partially decompress within the dispensing volume.

In certain exemplary implementations (not claimed), a method for operating a curable material dispensing system includes applying a secondary input force to a second control surface to move the second control surface from a disengaged position to an engaged position. The second control surface is maintained in the engaged position against a force provided by a biasing member. With the second control surface maintained in the engaged position, a primary input force is provided to a first control surface to move a lead screw distally along a translation axis to compress curable material within a dispensing volume. The secondary input force provided to the second control surface is removed to permit the biasing member to move the second control surface from the engaged position to the disengaged position. The second control surface in the disengaged position provides for movement of the lead screw proximally along the translation axis to permit the compressed curable material to at least partially decompress within the dispensing volume.

In certain exemplary implementations (not claimed), a method for operating a curable material dispensing system includes applying a primary input force to a first control surface while an actuator is biased into engagement with a locking nut to rotatably fix the locking nut about a translation axis. The threadable engagement provides for translation of the lead screw distally along the translation axis to compress curable material within a dispensing volume. A secondary input force is applied to a second control surface sufficient to overcome the force provided by a biasing member and move the actuator out of engagement from the locking nut and provide for rotation of the locking nut about the translation axis. The threadable engagement and the rotation of the locking nut permits translation of the lead screw proximally along the translation axis to permit the compressed curable material to at least partially decompress within the dispensing volume.

In certain exemplary implementations (not claimed), a method for operating a curable material dispensing system includes providing packaging with dimensions sufficient to accommodate a curable material dispensing system. The curable material dispensing system is provided including a housing, a dispensing volume coupled to the housing. An extension tube is provided that includes a flexible tube rotatably coupled to a rotating coupler, and an elbow coupler coupled to the rotating coupler. The elbow coupler of the extension tube is coupled to a distal end of the dispensing volume, thereby establishing fluid communication between the flexible tube and the dispensing volume. The flexile tube is articulated relative to the dispensing volume about the elbow coupler to a packaging configuration in which the flexible tube and the dispensing volume are substantially parallel and the flexible tube is positioned towards the dispensing volume relative to the elbow coupler. Thereafter, the curable material dispensing system and the extension tube are positioned within the packaging in the packaging configuration.

<FIG> show a system <NUM> for dispensing curable material. The system <NUM> includes a chamber <NUM> defining a dispensing volume <NUM> for receiving and dispensing the curable material. The curable material may be, for example, bone cement formed from mixing a powdered copolymer and a liquid monomer. In certain implementations, the chamber <NUM> may receive the pre-mixed curable material from a mixing and compression system <NUM> to which the system <NUM> is removably coupled. An exemplary mixing and compression system <NUM> suitable for the present application is disclosed in commonly owned International Publication No. <CIT>. Alternatively, it is contemplated that the chamber <NUM> may receive the powdered copolymer and/or the liquid monomer, and thereafter mix the contents within the dispensing volume <NUM> prior to dispensing the curable material in a manner to be described. Exemplary components suitable for the mixing the curable material within the dispensing volume <NUM> are disclosed in commonly owned <CIT>; <CIT>; <CIT>; <CIT>; <CIT>.

Before the start of the surgical procedure, the inventors of the subject application have recognized that known systems may require an undue amount of valuable space within the surgical suite. The systems may also require assembly of a flexible tube that is ultimately coupled to the access cannula, further consuming time and resources that could be diverted to other tasks associated with the surgical procedure. Still further, during the surgical procedure fluoroscopy may be utilized visualize the curable material within the bony anatomy. Known dispensing systems may not provide adequate maneuverability of the physician about the surgical site while holding the dispensing system to avoid the radiation associated with fluoroscopic imaging. Perhaps most importantly, for any number of reasons during the surgical procedure, it may be desirable for the physician to immediately cease delivery of the curable material, for example, recognition of a surgical complication such as an excessive amount of highly pressurized curable material being introduced into the body. Many known dispensing systems are inadequate for this purpose, as the compressed curable material at least partially decompresses along a path of least resistance, namely, out the system and into the patient. This concept, known as "drool" results in additional curable material being delivered into the patient, contrary to the intentions of the physician, until pressure gradient between the dispensing volume and the surgical site is sufficiently reduced. With concurrent reference to <FIG>, the exemplary chamber <NUM> includes a proximal end <NUM> and a distal outlet <NUM> positioned at least substantially opposite the proximal end <NUM>. The distal outlet <NUM> is in communication with the dispensing volume <NUM>. The chamber <NUM> may be elongate and substantially tubular in shape, as shown in <FIG>, or assume any suitable size and shape based on the design of the system <NUM> or demands of the surgical application.

The chamber <NUM> may include an inlet port <NUM> at least initially in fluid communication with the dispensing volume <NUM>. The inlet port <NUM> is adapted to be removably coupled with the mixing and compression system <NUM>. The curable material passing through the inlet port <NUM> and into the dispensing volume <NUM> defines a transfer phase. During the transfer phase, the inlet port <NUM> is in fluid communication with the dispensing volume <NUM> and the distal outlet <NUM>. With reference to <FIG>, the inlet port <NUM> may include a neck portion <NUM> extending from the chamber <NUM>. The neck portion <NUM> may define an aperture <NUM> in communication with the dispensing volume <NUM>. The neck portion <NUM> may be tubular in shape and include at least one rib <NUM> extending radially outward. <FIG> shows two ribs <NUM> in a generally helical arrangement. The ribs <NUM> are configured to cooperate with complementary features of a release assembly <NUM> of the mixing and compression system <NUM> to draw the inlet port <NUM> into sealing engagement with an outlet port (not identified) of the mixing and compression system <NUM>. A seal <NUM> may be at least partially disposed within the neck portion <NUM>. The seal <NUM> may include coupling features <NUM> configured to engage complementary coupling features <NUM> of the neck portion <NUM> to axially retain the seal <NUM>. <FIG> shows the coupling features <NUM> as deflectable fingers configured to resiliently deflect to engage openings at least partially forming the complementary coupling features <NUM>. With the seal <NUM> coupled to the neck portion <NUM>, a lumen <NUM> extending through the seal <NUM> is in selective communication with the dispensing volume <NUM>.

Returning to <FIG>, during dispensing of the curable material from the distal outlet <NUM> in the manner to be described, a sealing interface <NUM> between the plunger <NUM> and the chamber <NUM> may move distal to the inlet port <NUM> with distal movement of the plunger <NUM>, after which the inlet port <NUM> may no longer be considered in fluid communication with the dispensing volume <NUM> and the distal outlet <NUM>. The sealing interface <NUM> may be defined between an outer surface of the plunger <NUM> and an inner surface of the chamber <NUM>. The sealing interface <NUM> may be defined by a seal (not shown) coupled to the plunger <NUM>. The seal may be an O-ring (uncoated or coated with a friction-reducing material) or other compression seal, or a dynamic seal. The dynamic seal, for example a feather tip seal, provides for a sealing force proportional to the force on the seal itself. As the plunger <NUM> moves relative to the chamber <NUM>, friction at the sealing interface <NUM> may drop to near zero while sealing the curable material distal to the plunger <NUM>. The sealing interface <NUM>, whether or not defined by a discrete seal, is configured with minimal friction while maintaining the sealing properties between the plunger <NUM> and the chamber <NUM>. Among additional advantages to be described, providing minimal friction at the sealing interface <NUM> facilitates a backdrivable system and improved feedback to the physician during operation of the curable material delivery system <NUM>.

A chamber mount <NUM> may be coupled to or integrally formed with the chamber <NUM> at or near the proximal end <NUM> to, among other things, secure the chamber <NUM> a housing <NUM>. The chamber mount <NUM> may include opposing struts <NUM> extending laterally outward from the chamber <NUM> and adapted to be seated within correspondingly shaped slots <NUM> (one shown in <FIG>) defined within the housing <NUM>. The opposing struts <NUM> may also extend in a proximal-to-distal direction to a position proximal to the proximal end <NUM> of the chamber <NUM>, and at least partially define a void <NUM> sized to accommodate several components of the system <NUM> to be described. The void <NUM> may be bound laterally by the opposing struts <NUM>, and proximally by a proximal ring <NUM>. Further, the void <NUM> may be bound distally by the proximal end <NUM> of the chamber <NUM>. The void <NUM> may be open on sides not including the opposing struts <NUM>. At least one of the opposing struts <NUM> may include an opening <NUM> sized to receive an engagement feature <NUM> of an actuator <NUM> such that a locking nut <NUM> disposed within the void <NUM> may be engaged by the actuator <NUM> in a manner to be described.

A distal coupler <NUM> of the chamber <NUM> is adapted to be removably coupled to an extension tube <NUM> (see <FIG>) to be described. The extension tube <NUM> may be adapted to be coupled to a surgical instrument placed within the patient, such as an access cannula penetrating the bony anatomy. The distal coupler <NUM> may be a Luer fitting, a bayonet mount, or other suitable connection adapted to be removably receive an elbow coupler <NUM> of the extension tube <NUM> of the present disclosure, or a proximal end of a known tubular device.

The chamber <NUM> may be at least partially formed from translucent or transparent material such that the curable material (and the plunger <NUM>) within the dispensing volume <NUM> is visible to the physician. Indicia (not shown) may be provided on the outer surface <NUM> of the chamber <NUM> to provide the physician with an amount of the curable material within the dispensing volume <NUM>, and/or the amount of the curable material dispensed from the dispensing volume <NUM>; i.e., based on a determined distance traveled by the plunger <NUM> within the dispensing volume <NUM>. The indicia may be numerical graduations corresponding to a volume of the dispensing volume <NUM> (e.g., in cubic centimeters).

Referring to <FIG>, the plunger <NUM> is slidably disposed within the dispensing volume <NUM>. The plunger <NUM> is movable within the dispensing volume <NUM> in a distal direction (D) and a proximal direction (P). In particular, the plunger <NUM> is adapted to be advanced in the distal direction, to urge and/or compress the curable material (CM) within the dispensing volume <NUM>, thereby urging at least a portion of the compressed curable material from the distal outlet <NUM>. To facilitate the distal advancement of the plunger <NUM>, the curable material dispensing system <NUM> includes a first control surface <NUM> adapted to receive a primary input from a user, and a lead screw <NUM> operably coupled to the first control surface <NUM>. The plunger <NUM> is coupled to the lead screw <NUM>, for example, at or near a distal end <NUM> of the lead screw <NUM>, as shown in <FIG> and <FIG>. The lead screw <NUM> is rotatably fixed relative to the first control surface <NUM>. In a manner to be further described, the application of the primary input force, for example, a first input torque to the first control surface <NUM> in a first direction provides for rotation of the lead screw <NUM> with corresponding distal advancement of the plunger <NUM> within the dispensing volume <NUM>. Conversely, the application of a second input torque to the first control surface <NUM> in a second direction opposite the first direction may provide for rotation of the lead screw <NUM> with corresponding movement of the plunger <NUM> in the proximal direction within the dispensing volume <NUM>. It is contemplated that the plunger <NUM> may be rotatable relative to the lead screw <NUM> in a manner to reduce friction between the plunger <NUM> and the lead screw <NUM>. The reduced friction between the plunger <NUM> and the lead screw <NUM> may facilitate backdriving of the system <NUM>, such as during the movement of the plunger <NUM> in the proximal direction.

Referring now to <FIG> and <FIG>, the lead screw <NUM> includes the distal end <NUM> and a proximal end <NUM> opposite the distal end <NUM>. A translation axis (TA) may be defined between the proximal and distal ends <NUM>, <NUM> of the lead screw <NUM>. The first control surface <NUM> may be associated with a handle <NUM>. The handle <NUM> may include a proximal end <NUM>, a distal end <NUM>, and a lumen <NUM> at least partially extending between the proximal and distal ends <NUM>, <NUM> of the handle <NUM>. The lumen <NUM> may be coaxially disposed on the translation axis with at least a portion of the handle <NUM> extending from the interior <NUM> of the housing <NUM>. The proximal end <NUM> of the lead screw <NUM> may be positioned within the lumen <NUM>, as best shown in <FIG>. The handle <NUM> may further include drive features <NUM> defining at least a portion of the lumen <NUM>. The drive features <NUM> of the handle <NUM> are adapted to engage with driven features <NUM> of the lead screw <NUM> complimentary to the drive features <NUM> such that the lead screw <NUM> is rotatably fixed relative to the first control surface <NUM> of the handle <NUM>. With reference to <FIG>, for example, the drive features <NUM> may define a rectangular-shaped lumen at least partially extending between the proximal and distal ends <NUM>, <NUM> of the handle <NUM>. The drive features <NUM> may further include slots <NUM> at least partially defining the lumen <NUM>. The driven features <NUM> may be defined by the proximal end <NUM> of the lead screw <NUM> being at least substantially rectangular and sized to the lumen <NUM> of the handle <NUM>. The driven features <NUM> may further include at least one ridge <NUM> (e.g., defined by a chord of the lead screw <NUM>) extending longitudinally along the lead screw <NUM>. The drive and driven features <NUM>, <NUM> are engaged to prevent relative rotation between the lead screw <NUM> and the handle <NUM>, but permit axial movement of the lead screw <NUM> relative to the first control surface <NUM> of the handle <NUM> along the translation axis.

The handle <NUM> may include a shaft <NUM> and a grip portion <NUM> coupled to the shaft <NUM>. The grip portion <NUM> at least partially defines the first control surface <NUM>. <FIG> shows the grip portion <NUM> positioned proximal to and extending radially outwardly from the shaft <NUM>. The grip portion <NUM> is sized to be griped by one hand of the physician during operation. The first control surface <NUM> may be annularly disposed about the grip portion <NUM>. At least the first control surface <NUM> of the grip portion <NUM> may be formed from material(s) with increased tack (e.g., rubber) to prevent inadvertent slipping of the hand during application of the first and second input torques to the first control surface <NUM>. Further, at least the first control surface <NUM> of the grip portion <NUM> may include indentations and/or ridges to facilitate improved grip during use. Directional indicia (not shown) may be disposed on the handle <NUM> to provide guidance to the physician as to the first direction of rotation.

When the lead screw <NUM> is rotatably fixed relative to the first control surface <NUM>, providing the first and second input torques to the first control surface <NUM> imparts rotation of the handle <NUM> and therefore, rotation of the lead screw <NUM>. Yet the distal and proximal movement of the plunger <NUM> along the translation axis requires corresponding distal and proximal movement of the lead screw <NUM> coupled to the plunger <NUM>. To facilitate, for example, distal movement of the plunger <NUM> and the lead screw <NUM> along the translation axis, the curable material dispensing system <NUM> includes a locking nut <NUM> including internal threads <NUM>. With particular reference to <FIG>, the internal threads <NUM> of the locking nut <NUM> threadably engage external threads <NUM> of the lead screw <NUM> at least partially extending between its proximal and distal ends <NUM>, <NUM>. The locking nut <NUM> may be disposed within the interior <NUM> of the housing <NUM> and disposed coaxially on the translation axis. The locking nut <NUM> includes an aperture <NUM> for receiving the lead screw <NUM>. <FIG> shows the lead screw <NUM> coaxially extending through the aperture <NUM> of the locking nut <NUM> with the internal threads <NUM> of the locking nut <NUM> in threadable engagement with the external threads <NUM> of the lead screw <NUM>. The threadable engagement of the internal threads <NUM> of the locking nut <NUM> and the external threads <NUM> of the lead screw <NUM> provides for the distal advancement of the lead screw <NUM> (and the plunger <NUM>) relative to the locking nut <NUM> in response to the first control surface <NUM> receiving the first input torque from the user. It is noted that the internal threads <NUM> of the locking nut <NUM> extend about an entirety of the aperture <NUM> (i.e., <NUM> degrees), whereas the external threads <NUM> encircle less than an entirety of the lead screw <NUM> to define partial threading (e.g., <NUM>, <NUM>, <NUM> degrees, etc.). The ridge(s) <NUM> extend between portions of the lead screw <NUM> not having the external threads <NUM>. Alternatively, the internal threads <NUM> and/or the external threads <NUM> may extend about and encircle, respectively, all or less than <NUM> degrees.

<FIG>, <FIG> and <FIG> best show the locking nut <NUM> including a hub <NUM> and a ring gear <NUM> coupled to the hub <NUM>. The hub <NUM> defines the aperture <NUM> and includes the internal threads <NUM> disposed about the aperture <NUM>. The hub <NUM> may be disposed within a recess defined by the ring gear <NUM>. The aperture <NUM> may be defined by the hub <NUM> and sized to receive the lead screw <NUM>. The locking nut <NUM> may be formed from suitable materials including polymers, metals, combinations thereof, and the like.

The curable material dispensing system <NUM> provides for selectively preventing rotation of the locking nut <NUM> about the translation axis, resulting in the locking nut <NUM> providing for the distal advancement of the lead screw <NUM> with rotation of the same. Otherwise, when the locking nut <NUM> is permitted to rotate about the translation axis, rotation of the lead screw <NUM> results in concurrent rotation of the lead screw <NUM> and the locking nut <NUM> (due to characteristics of the internal threads <NUM> and the external threads <NUM>) with minimal distance advancement of the lead screw <NUM> relative to the locking nut <NUM>. Yet when the locking nut <NUM> is prevented from rotation about the translation axis, rotation of the lead screw <NUM> results in the distal advancement of the lead screw <NUM> relative to the locking nut <NUM> due to the threadable engagement between the internal threads <NUM> of the locking nut <NUM> and the external threads <NUM> of the lead screw <NUM>. Likewise, when the locking nut <NUM> is prevented from rotation relative to the housing <NUM>, rotation of the lead screw <NUM> results in the distal advancement of the lead screw <NUM> relative to the housing <NUM> due to the threadable engagement between the internal threads <NUM> of the locking nut <NUM> and the external threads <NUM> of the lead screw <NUM>.

In order to selectively prevent rotation of the locking nut <NUM> about the translation axis, the locking nut <NUM> may include an engagement feature <NUM>. In a manner to be described, the engagement feature <NUM> is adapted to be engaged (with application of a secondary input force) to prevent rotation of the locking nut <NUM> about the translation axis.

The engagement feature <NUM> may include a plurality of teeth <NUM>. The teeth <NUM> may extend radially from the ring gear <NUM>, and more particularly, be disposed annularly about the ring gear <NUM> of the locking nut <NUM>. The teeth <NUM> may be disposed about the distal and/or proximal rings <NUM>, <NUM> forming the ring gear <NUM> of the locking nut <NUM>. Alternatively, the engagement feature may be a notch, protrusion, etc..

Returning again to <FIG> and <FIG>, the system <NUM> may include an actuator <NUM> adapted to selectively engage the engagement feature <NUM> of the locking nut <NUM>. The actuator <NUM> includes a second control surface <NUM> adapted to receive the secondary input force from the user. The actuator <NUM> further includes an engagement feature <NUM> complimentary to the engagement feature <NUM> of the locking nut <NUM>, for example, complimentary teeth <NUM>. With concurrent reference to <FIG> the actuator <NUM> may be a lever <NUM> pivotably coupled to the housing <NUM>. The illustrated lever <NUM> is generally rectangular in shape and defines the second control surface <NUM> oriented away from the housing <NUM> so as to receive the secondary input force from the user. Alternatively, the actuator <NUM> may be a button, toggle switch, slider, and the like.

The teeth <NUM> are coupled to the actuator <NUM> and positioned generally opposite to the second control surface <NUM> so as to be oriented towards the locking nut <NUM>. The teeth <NUM> may be arranged in a manner complimentary to an arcuate portion of the teeth <NUM> extending annularly about the locking nut <NUM>. It is further contemplated that the actuator may be movable coupled to the housing <NUM> in other ways beyond pivotable coupling, such as slidable engagement, etc. The actuator <NUM> is operable between an engaged position and a disengaged position. In the engaged position, the complimentary engagement feature <NUM> engages the engagement feature <NUM> of the locking nut <NUM> to prevent rotation of the locking nut <NUM> about the translation axis. For example, the teeth <NUM> of the actuator <NUM> engage the teeth <NUM> of the locking nut <NUM>. With the actuator <NUM> coupled to the housing <NUM>, the locking nut <NUM> is rotatably fixed relative to the housing <NUM> when the actuator <NUM> is in the engaged position. In the disengaged position, the teeth <NUM> of the actuator <NUM> are spaced away from or otherwise disengaged from the teeth <NUM> of the locking nut <NUM>. The locking nut <NUM> may rotate about the translation axis and relative to the housing <NUM> when the actuator <NUM> is in the disengaged position. The secondary input force provided to the second control surface <NUM> moves the actuator <NUM> between the engaged and disengaged positions. For example, the lever <NUM> may be initially in the disengaged position represented in <FIG>. The user applies the secondary input force, such as a downward force to the lever <NUM> while supporting the housing <NUM>. The lever <NUM> pivots relative to the housing <NUM> with the teeth <NUM> of the actuator <NUM> moving towards the teeth <NUM> of the locking nut <NUM>. The teeth <NUM>, <NUM> mesh to further define the engaged position of the actuator <NUM>.

The system <NUM> may include a biasing member <NUM> operably coupled to the actuator <NUM>. The biasing member <NUM> may bias the actuator <NUM> towards the disengaged position. For example, <FIG> shows the biasing member <NUM> being a coil spring adapted to engage a recess <NUM> on an underside of the actuator <NUM> (see <FIG>). When the actuator <NUM> is in the engaged position, as shown in <FIG>, the coil spring is compressed between the actuator <NUM> and the housing <NUM>. Thus, the biasing member <NUM> may be adapted to bias the lever <NUM> away from the housing <NUM>. As a result, application of the secondary input force to the second control surface <NUM> overcomes a biasing force provided by the biasing member <NUM> to move the actuator <NUM> from the disengaged position to the engaged position. Conversely, removal of secondary input force from the second control surface <NUM> provides for the biasing member <NUM> moving the actuator <NUM> from the engaged position to the disengaged position. The biasing member <NUM> may alternatively be a torsion spring, spring clip, constant force spring, or other suitable mechanism for biasing the actuator <NUM> to the disengaged position.

Alternatively, it is contemplated that the biasing member may be coupled to the in a manner that biases the actuator <NUM> to the engaged position, and the secondary input force applied to the second control surface <NUM> moves the actuator <NUM> from the engaged position to the disengaged position (i.e., the converse arrangement than as previously described). In such an implementation, the engagement feature <NUM> of the locking nut <NUM> may be engaged with, for example, teeth (not shown) positioned opposite the locking nut <NUM> from the actuator <NUM>. The teeth are biased into engagement with the engagement feature <NUM> in the absence of the input of the secondary input force to the second control surface <NUM>. The actuator <NUM> is biased into a position away from the locking nut <NUM> (e.g., the position shown in <FIG>). Further, the actuator <NUM> is operably coupled to the teeth positioned opposite the locking nut <NUM>. The application of the secondary input force to the second control surface <NUM> moves the actuator <NUM> towards the housing <NUM>, which disengages the teeth from the engagement feature <NUM> against the biasing force provided by the biasing member. The locking nut <NUM>, no longer constrained by the teeth rotatably fixed relative to the housing <NUM>, may then rotate about the translational axis for reasons described throughout the present disclosure.

With the actuator <NUM> in the engaged position, application of the primary input force to the first control surface <NUM> results in rotation of the lead screw <NUM> about the translation axis and distal advancement along the translation axis due to the threadable engagement between the lead screw <NUM> and the locking nut <NUM>. The distal advancement of the lead screw <NUM> results in the distal advancement of the plunger <NUM> within the dispensing volume <NUM>. The curable material within the dispensing volume <NUM> is compressed and/or dispensed from the distal outlet <NUM>. In the context of an exemplary surgical procedure for use with the curable material dispensing system <NUM>, namely a vertebroplasty, the curable material may be dispensed to the extension tube <NUM> and through the access cannula directed through the cortical bone and into the cancellous region of the vertebral body.

Yet for any number of reasons, it may be desirable for the physician to immediately cease delivery of the curable material into, for example, the cancellous region of the vertebral body. As mentioned, one example is recognition an excessive amount of the curable material being introduced into the body. Despite removal of the physician's input, many known systems result in "drool" and additional curable material being delivered into the patient, contrary to the intentions of the physician. One of the many advantageous features of the system <NUM> of the present disclosure includes providing for proximal movement of the lead screw <NUM> (and the plunger <NUM>) in a manner that minimizes or eliminates drool from the distal outlet <NUM> of the dispensing volume <NUM>. In a manner to be explained in greater detail, the internal threads <NUM> of the locking nut <NUM> and the external threads <NUM> of the lead screw <NUM> are configured to provide for rotation of the locking nut <NUM> about the translation axis when the actuator <NUM> is in the disengaged position. The rotation of the locking nut <NUM> permits the plunger <NUM> to move proximally along the translation axis, and further permit the compressed curable material to at least partially decompress within the dispensing volume <NUM>, as opposed to decompressing through the distal outlet <NUM>.

Returning to <FIG>, the system <NUM> is shown with the actuator <NUM> in the engaged position. In particular, the lever <NUM> may be positioned adjacent the housing <NUM> with the second control surface <NUM> substantially flush with the housing <NUM>. The teeth <NUM> of the actuator <NUM> engage the teeth <NUM> of the locking nut <NUM> such that the locking nut <NUM> is rotatably fixed relative to the housing <NUM>. As previously described, application of the first input torque to the first control surface <NUM> results in rotation of the lead screw <NUM> relative to the locking nut <NUM>, which further provides for advancement of the lead screw <NUM> in the distal direction (D) along the translation axis (TA). The distal advancement of the lead screw <NUM> results in advancement of the plunger <NUM> in the distal direction and corresponding compression of the curable material (CM) within the dispensing volume <NUM> (see <FIG>). In certain operating conditions, the curable material may be compressed to <NUM>,<NUM>, <NUM>,<NUM>, <NUM>,<NUM>, <NUM>,<NUM> or <NUM>,<NUM> or more bar (<NUM>, <NUM>, <NUM>, <NUM>, or <NUM> or more pounds per square inch (psi)). compression of the curable material results in forces on the plunger <NUM> along the translation axis in the proximal direction (P).

Should the physician desire to immediately cease delivery of the curable material from the dispensing volume <NUM>, the secondary input force provided to the second control surface <NUM> is simply removed. In manners previously described, the biasing member <NUM> biases the actuator <NUM> away from the housing <NUM> and from the engaged position to the disengaged position. Upon release of the secondary input force, the teeth <NUM> of the actuator <NUM> automatically disengage from the teeth <NUM> of the engagement feature <NUM> of the locking nut <NUM>. The locking nut <NUM>, no longer constrained by the actuator <NUM> rotatably fixed relative to the housing <NUM>, may rotate about the translation axis.

The rotation of the locking nut <NUM> about the translation axis permits the lead screw <NUM> to move in the proximal direction along the translation axis. The lead screw <NUM> is urged in the proximal direction along the translation axis by the forces on the plunger <NUM> from the curable material compressed within the dispensing volume <NUM>. The lead screw <NUM> translates in the proximal direction without rotation as the locking nut <NUM> rotates about the translation axis without translation. It is contemplated that some translation of the locking nut <NUM> may be provided or occur. The translation of the lead screw <NUM> in the proximal direction results in an increase in the dispensing volume <NUM> accessible to the compressed curable material. In other words, a portion of the dispensing volume <NUM> defined within the chamber <NUM> distal to the plunger <NUM> is increased. The curable material at least partially decompresses within the increased portion of the dispensing volume <NUM> now accessible to the compressed curable material. Further, with a diameter of the chamber <NUM> often being greater than a diameter of the distal outlet <NUM>, even minimal movement of the plunger <NUM> in the proximal direction provides increased volume within the dispensing volume <NUM> for the curable material to decompress. In other words, the compressed curable material encounters less resistance within the increased portion of the dispensing volume <NUM> as opposed to exiting the distal outlet <NUM>. The curable material is decompressed sufficiently to reduce the pressure gradient between the dispensing volume <NUM> and the surgical site in view of the viscosity of the partially compressed curable material. Therefore, the likelihood of drool is minimized or eliminated with the curable material dispensing system <NUM>.

The movement of the lead screw <NUM> in the proximal direction is based on the interaction between the internal threads <NUM> of the locking nut <NUM> and the external threads <NUM> of lead screw <NUM>. In other words, the internal threads <NUM> of the locking nut <NUM> and the external threads <NUM> of lead screw <NUM> are configured to provide for a backdrivable system. The backdrivable system may include the internal threads <NUM> of the locking nut <NUM> and the external threads <NUM> of lead screw <NUM> being defined by a screw efficiency of greater than <NUM>%. In other words, if the screw efficiency is less than <NUM>%, based on, for example, pitch of the threads <NUM>, <NUM>, friction between the threads <NUM>, <NUM>, and the like, the system <NUM> will not be backdrivable and the locking nut <NUM> will not rotate in response to the torque being transferred from the lead screw <NUM> being urged proximally by the compressed curable material. Stated differently, the forces from the compressed curable material on the plunger <NUM> and the lead screw <NUM> in the proximal direction results in a torque on the locking nut <NUM> greater than a backdriving torque (Tb) of the system <NUM> according to Equation <NUM>: <MAT> where F is the axial load, P is the screw lead, and η<NUM> is the efficiency of the screw. Consequently, if the backdriving torque (Tb) of the system <NUM> is greater than the total friction torque, backdriving will occur. It is contemplated that any suitable material and dimensional design characteristics may be provided to the lead screw <NUM> and/or the locking nut <NUM> in order to achieve screw efficiency of greater than <NUM>% and provide for translation of the lead screw <NUM> along the translation axis with corresponding rotation of the locking nut <NUM> about the translation axis. For example, having the external threads <NUM> not fully encircle the lead screw <NUM> may facilitate achieving lesser friction and greater screw efficiency.

In addition to minimizing or eliminating drool, the design of the lead screw <NUM> of the system <NUM>, including the screw efficiency, provides for several additional benefits to be described. First, the forces from the compressed curable material on the plunger <NUM> (e.g., backpressure) is more efficiently transmitted to the hand(s) of the physician holding the system <NUM>, and in particular the first control surface <NUM>. This improves tactile feel for the physician, which may further provide for improved awareness of the volume of the curable material being dispensed from the dispensing volume <NUM> during use of the system <NUM>. In other words, frictional losses within the system <NUM> are minimized, and thus more precise control is realized with each first input torque to the first control surface <NUM> resulting in predictable and precise volumes being dispensed from the dispensing volume <NUM>. Second, efficiency is not sacrificed with the improved tactile feel provided to the physician. The mechanical advantage of the system <NUM> is substantially preserved, which among other things, limits physician fatigue and avoids loss of procedure operating time often hampering less robust systems. Third, the preserved mechanical advantage of the system <NUM> also results in the compressed curable material being rapidly delivered to the patient per input torque of the physician (i.e., a "fast start"). In other words, the lead screw <NUM> requires less turns to dispense the same amount of curable material to the patient relative to known systems with appreciable frictional losses. In one example, approximately <NUM> to <NUM> cubic cementers of curable material may be delivered per <NUM>° revolution of the first control surface <NUM> without significant loss in mechanical advantage. Known systems with lead screws are limited to less than <NUM> cubic cementers per <NUM>° revolution; otherwise, the frictional losses associated with a higher pitched lead screws require undesirably high inputs from the physician with associated increase in fatigue and working time. It is further contemplated that the internal threads <NUM> of the locking nut <NUM> and the external threads <NUM> of lead screw <NUM> may be modified as desired to alter the characteristics of the fast start. Likewise, lubricants and/or coatings may be applied to the lead screw <NUM> and/or the locking nut <NUM> to alter the characteristics of the fast start.

When the plunger <NUM> and the lead screw <NUM> are moving in the proximal direction, in particular during the backdriving of the system <NUM>, it is desirable to limit or eliminate translation of the locking nut <NUM> along the translation axis. In particular, limiting or eliminating translation of the locking nut <NUM> along the translation axis more efficiently provides for rotation of the locking nut <NUM> about the translation axis for reasons previously described. Therefore, it is contemplated to include one or more bushings <NUM> and/or one or more bearings <NUM> positioned adjacent to or in abutment with the locking nut <NUM> within the interior <NUM> of the housing <NUM>. <FIG> and <FIG> shows the system <NUM> including two bushings <NUM> with the bearing <NUM> being a thrust bearing positioned intermediate the two bushings <NUM>. Suitable means for reducing friction other than the thrust bearing are contemplated, such as ball bearings, needle bearings, lubricants, coatings, and the like. The tolerances between the bushings <NUM>, the bearing <NUM>, and the proximal ring <NUM> are designed to minimize or eliminate translation of the locking nut <NUM> in the proximal direction along the translation axis, and the bearing <NUM> is configured to facilitate rotation of the locking nut <NUM> about the translation axis.

As the plunger <NUM> is urged in the proximal direction along the translation axis by the forces on the plunger <NUM> from the curable material compressed within the dispensing volume <NUM>, the axial forces are transmitted to the lead screw <NUM> and the locking nut <NUM> in threadable engagement with the lead screw <NUM>. At least portion of the chamber mount <NUM>, in particular the proximal ring <NUM>, may define a loadbearing surface <NUM>, is adapted to accommodate stress, strain, fatigue, wear, and the like, associated with appreciable forces transmitted from the compressed curable material to the lead screw <NUM> and the locking nut <NUM>. In particular, the chamber mount <NUM> may define the void <NUM> sized to receive the locking nut <NUM>, the bushing(s) <NUM>, and/or the bearing <NUM>. The axial forces may be transmitted from the locking nut <NUM>, the bushings <NUM>, and the bearing <NUM>, to the loadbearing surface <NUM> and the opposing struts <NUM> fixed to the chamber <NUM>. In such an implementation, the housing <NUM> may be considered non-load bearing, and thus may be formed from less robust materials and/or less complex manufacturing processes. In particular, the void <NUM> accommodating the locking nut <NUM> is effectively integral into the chamber <NUM> (via the opposing struts <NUM>) such that, when the chamber <NUM> is coupled to the housing <NUM>, forces transmitted from the compressed curable material to the lead screw <NUM> and the locking nut <NUM> are internalized or dissipated within the chamber <NUM> itself.

Other suitable designs of the chamber <NUM>, the chamber mount <NUM>, and/or the housing <NUM> are contemplated consistent with the objects of the above disclosure. In one example, the second control surface <NUM> is operably coupled to the chamber <NUM> (as opposed to the housing <NUM>) with the engagement features <NUM> coupled to the second control surface <NUM> configured to engage the teeth <NUM> of the locking nut <NUM> manners previously described. In such an example, any loading on the second control surface <NUM> (e.g., at the pivot of the lever <NUM>) is internalized or dissipated within the chamber <NUM> itself, further rendering the housing <NUM> non-loadbearing.

As previously described in detail, the curable material dispensing system <NUM> provides for distal advancement of the plunger <NUM> in response to the first control surface <NUM> receiving the primary input force (e.g., the first input torque to the handle <NUM>) with the actuator <NUM> in the engaged position. This may be effectuated by the physician applying the secondary input force to the second control surface <NUM> to maintain the actuator <NUM> in the engaged position with one hand, while simultaneously applying the first input torque to the first control surface <NUM> with another hand. For any number of reasons, the physician may remove the first hand from the first control surface <NUM>. Most often, the physician does so in order to reset his or her hand for a subsequent application of the first input torque. Another example may include the physician needing to perform another aspect of the surgical procedure with the first hand while supporting the system <NUM> with the second hand. Yet based on the backdrivable aspects of the lead screw <NUM> and the locking nut <NUM>, removing the primary input force from the first control surface <NUM> (with the actuator <NUM> in the engaged position) would otherwise result in the compressed curable material within the dispensing volume <NUM> forcing the plunger <NUM> and the lead screw <NUM> to rotate (and move in the proximal direction) with corresponding rotation of the first control surface <NUM>. In other words, with the actuator <NUM> in the engaged position, the threads <NUM>, <NUM> would cause the lead screw <NUM> to rotate within the locking nut <NUM> rotatably fixed relative to the housing <NUM>. The rotation of the lead screw <NUM> in the second direction would sacrifice the distal advancement of the plunger <NUM>, and undesirably require the physician to reestablish the position of the plunger <NUM> before continuing with the procedure. To overcome this potential shortcoming, the curable material dispensing system <NUM> includes the unidirectional torque mechanism <NUM>.

Referring now to <FIG>, <FIG>, <FIG> and <FIG>, the unidirectional torque mechanism <NUM> may be operably coupled to the first control surface <NUM>. The unidirectional torque mechanism <NUM> may be adapted to permit for rotation of the first control surface <NUM> about the translation axis in the first direction (e.g., R<NUM> of <FIG>), and generally prevent rotation of the first control surface <NUM> about the translation axis in the second direction (e.g., R<NUM> of <FIG>). More specifically, the unidirectional torque mechanism <NUM> permits the distal advancement of the lead screw <NUM> during application of the first input torque to the handle <NUM> in the first direction, and prevent proximal movement of the lead screw <NUM> upon removal of the first input torque. As a result, the physician is free to rotate the handle <NUM> in the first direction to distally advance the plunger <NUM> by a desired extent, then reset his or her hand on the handle <NUM> and/or perform another aspect of the surgical procedure without sacrificing the distal advancement of the plunger <NUM>.

The unidirectional torque mechanism <NUM> may be a ratcheting mechanism including a ratchet member such as a ratchet ring <NUM> and at least one pawl <NUM>. The pawl <NUM> is seated within a recess <NUM> defined by a flange <NUM> coupled to the handle <NUM>. <FIG> shows a lug <NUM> extending radially outwardly from the shaft <NUM> of the handle <NUM> such that the lug <NUM> is coaxially disposed on the translation axis. The lug <NUM> may be provided at any suitable position on the shaft <NUM> between the proximal and distal ends <NUM>, <NUM> of the handle <NUM>. More than one recess <NUM> may be provided, such as the two recesses positioned on opposing sides of the lug <NUM>. The pawl <NUM> is dimensioned to be at least partially seated within the recess <NUM>. A biasing element <NUM> may be provided and operably coupled to the handle <NUM> and the pawl <NUM>. The biasing element <NUM>, for example, a coil spring or a torsion spring, biases the pawl <NUM> radially outwardly, thereby exposing the pawl <NUM> beyond the outer circumference of the lug <NUM> to engage the ratchet ring <NUM> in a manner to be described.

The ratchet ring <NUM> may be coaxially disposed on the translation axis and coaxially aligned with the lug <NUM> of the handle <NUM>. The ratchet ring <NUM> is further positioned to encircle the lug <NUM> such that an inner surface <NUM> of the ratchet ring <NUM> is oriented towards the lug <NUM>, and more particularly towards the pawl <NUM> seated within the lug <NUM> (see <FIG> and <FIG>). In other words, the ratchet ring <NUM> is operably coupled to the first control surface <NUM> at an interface between the inner surface <NUM> and the pawl <NUM> coupled to the lug <NUM>. With reference to <FIG> and <FIG>, the ratchet ring <NUM> includes the inner surface <NUM> opposite an outer surface <NUM> and defining a proximal portion <NUM> of the ratchet ring <NUM>. The ratcheting mechanism includes ratchet teeth <NUM> circumferentially disposed about the inner surface <NUM> of the ratchet ring <NUM>. Each of ratchet teeth <NUM> may be asymmetrical and defined by a trailing edge facing the first direction (R<NUM>) and a leading edge facing the second direction (R<NUM>). With the first input torque provided to the primary control surface <NUM> in the first direction, the handle <NUM> and the pawl <NUM> coupled to the handle <NUM> rotate in the first direction about the translation axis. The pawl <NUM>, biased towards the inner surface <NUM> with the biasing element <NUM>, contacts the leading edge of the one of the ratchet teeth <NUM>. Based on the shape of the leading edge (e.g., a ramp-like surface), the pawl <NUM> is urged away from the inner surface <NUM> with the biasing element <NUM> being resiliently deformed as the pawl <NUM> moves past each of the ratchet teeth <NUM>. Assuming the locking nut <NUM> is rotatably fixed about the translation axis, the first control surface <NUM> is rotated with relatively little resistance with corresponding distal advancement of the lead screw <NUM>.

With the second input torque provided to the primary control surface <NUM> in the second direction, the handle <NUM> and the pawl <NUM> coupled to the handle <NUM> rotate in the second direction about the translation axis until the pawl <NUM> engages the trailing edge of one of the ratchet teeth <NUM>. The trailing edge of the ratchet <NUM> and a tip of the pawl <NUM> are shaped to firmly engage such that the primary control surface <NUM> cannot be further rotated in the second direction (in the absence of a defeatable mechanism to be described). Thus, the unidirectional torque mechanism <NUM> is adapted to permit for rotation of the first control surface <NUM> about the translation axis in the first direction, and generally prevent rotation of the first control surface <NUM> about the translation axis in the second direction. It is to be understood that the second input torque may originate from the lead screw <NUM> being urged proximally under the influence of the compressed curable material within the dispensing volume <NUM>. Thus, the unidirectional torque mechanism <NUM> prevents proximal movement of the lead screw <NUM> rotatably fixed to the primary control surface <NUM> (and when the locking nut <NUM> is rotatably fixed about the translation axis).

Operation of the curable material dispensing system <NUM> may provide an audible indication and/or a tactile feedback to the physician. The unidirectional torque mechanism <NUM> may be configured to provide for an impact that may be heard and/or be felt by the hand of the physician holding the handle <NUM>. In one non-limiting example, the biasing element <NUM> biases the pawl <NUM> towards the inner surface <NUM> of the ratchet ring <NUM>. As the pawl <NUM> passes the trailing edge of each of the ratchet teeth <NUM> in the first direction, a brief moment occurs where a small gap exists between the pawl <NUM> and the inner surface <NUM> with the biasing element <NUM> being resiliently deformed. In other words, trailing edge of the ratchet teeth <NUM> may be shaped as a "plateau" relative to the inner surface <NUM> of the ratchet ring <NUM>. Immediately upon passing the trailing edge at which the biasing element <NUM> is resiliently deformed, the biasing element <NUM> urges the pawl <NUM> towards the inner surface <NUM>, quickly closing the gap. The impact between the pawl <NUM> and the inner surface <NUM> may provide the audible indication and/or the tactile feedback to the physician. In other words, the pawl <NUM> and the ratchet ring <NUM> may be formed from materials, such as metal or plastic, to provide a "click" as the pawl <NUM> strikes the inner surface <NUM> of the ratchet ring <NUM>. Likewise, the pawl <NUM> strikes the inner surface <NUM> of the ratchet ring <NUM> may be with suitable force to be felt by the hand of the physician holding the handle <NUM>.

With continued reference to <FIG>, the ratchet teeth <NUM> may be circumferentially spaced equally about the inner surface <NUM> of the ratchet ring <NUM>. As a result, an angular displacement of rotation of the first control surface <NUM> about the translation axis may be fixed between each successive audible indication and/or tactile feedback. Provided the locking nut <NUM> is rotatably fixed about the translation axis during the input of the first input torque to the first control surface <NUM>, the angular displacement between each one of the equally spaced ratchet teeth <NUM> is associated with a fixed distance of the distal advancement of the lead screw <NUM> and the plunger <NUM> along the translation axis. By extension, the fixed distance of the distal advancement of the lead screw <NUM> and the plunger <NUM> along the translation axis may be associated with a fixed volume of compressed curable material dispensed from the dispensing volume <NUM>. For example, each successive audible indication and/or tactile feedback may be associated with <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. 0cc being dispensed from the dispensing volume <NUM>. The fixed volume associated with each successive audible indication and/or tactile feedback may be based, at least in part, on circumferential spacing between the ratchet teeth <NUM>, the pitch of the internal threads <NUM> of the locking nut <NUM> and the external threads <NUM> of the lead screw <NUM>, and the like. While the movement of the plunger <NUM> may also be visible through the chamber <NUM> when formed from transparent materials, the audible indications and/or tactile feedback being associated with a fixed volume of curable material provides supplemental means for the physician to assess the amount of the curable material being dispensed from the system <NUM>.

Alternatively, the unidirectional torque mechanism <NUM> may not include the biasing element <NUM> biasing the pawl <NUM> towards the inner surface <NUM> of the ratchet ring <NUM>. The pawl <NUM> may be formed from resilient, semi-rigid, and/or shape memory material(s) (e.g., Nitinol) adapted to deflect under the forces from the ratchet teeth <NUM> as the pawl <NUM> moves past each of the ratchet teeth <NUM>, then return to an original shape (in contact with the inner surface <NUM>) after passing the trailing edge of the ratchet teeth <NUM> in the first direction. It should be also be appreciated that the ratchet ring may have alternative shapes and configurations other than what is shown, such as a polygonal shape. In certain implementations, the unidirectional torque mechanism <NUM> may be an overrunning clutch with a driver wheel adapted to be in engagement with a driven wheel. Other constructions of imparting unidirectional rotation between two structures may be implemented into the system of the present disclosure.

As previously described in detail, the curable material dispensing system <NUM> includes the safety feature of providing for proximal movement of the lead screw <NUM> along the translation axis in response to the actuator <NUM> being in the disengaged position. In implementations where the biasing member <NUM> biases the second control surface <NUM> away from the locking nut <NUM> (i.e., biases the second control surface such that the actuator is in the disengaged position), the safety feature can be activated by merely releasing the lever <NUM> with the lever <NUM> or other control surface acting as a so-called "dead man's switch. " Yet for any number of reasons, the physician may wish to provide for proximal movement of the lead screw <NUM> along the translation axis, for example, in addition to the proximal movement associated with the release of the "dead man's switch. " It is readily appreciated that the threads <NUM>, <NUM> typically would provide for proximal movement of the lead screw <NUM> along the translation axis but for the unidirectional torque mechanism <NUM>.

The curable material dispensing system <NUM> includes a defeatable unidirectional mechanism <NUM>. The defeatable unidirectional mechanism <NUM> operably couples the first control surface <NUM> and the housing <NUM>. The defeatable unidirectional mechanism <NUM> permits proximal movement of the lead screw <NUM> in response to the first control surface <NUM> receiving the second torque input exceeding a torque threshold. By extension, the defeatable unidirectional mechanism <NUM> prevents for the proximal movement of the lead screw <NUM> when the second input torque does not exceed the torque threshold. In a practical sense, the defeatable unidirectional mechanism <NUM> is configured to prevent the rotation of the handle <NUM> in the second direction when the lead screw <NUM> is urged proximally under the influence of the compressed curable material within the dispensing volume <NUM> (e.g., when the physician resets his or her hand), but permit the rotation of the handle <NUM> in the second direction from the physician deliberating applying sufficient torque to the primary input surface <NUM>, which would result in the proximal movement of the lead screw <NUM>. It is to be understood that the torque threshold may be based primarily on a frictional relationship defining a clutch mechanism (generally referred to as <NUM>) to be described, but also may further be based on friction between the internal and external threads <NUM>, <NUM>, the forces provided by the compressed curable material, and the like. Consequently, the torque threshold may be specifically designed (based on the characteristics of the clutch mechanism <NUM>) such that the typical torque on the handle <NUM> from only the lead screw <NUM> being backdriven and urged proximally is less than the torque threshold.

The defeatable unidirectional mechanism <NUM> is configured to permit for the distal advancement of the lead screw <NUM> in response to the first control surface <NUM> receiving the first input torque less than the torque threshold. In other words, in the first direction, the handle <NUM> is easily rotatable at a torque relatively less than that required to rotate the handle <NUM> in the second direction (e.g., as the pawl <NUM> moves passed the teeth <NUM> in the first direction). It is understood that as the curable material becomes increasingly compressed within the dispensing volume <NUM>, the first input torque required to distally advance the lead screw <NUM> (against the forces from the compressed curable material) increases beyond the torque threshold.

Referring now to <FIG>, <FIG> and <FIG>, the defeatable unidirectional mechanism <NUM> includes the unidirectional torque mechanism <NUM> previously described. In other words, the unidirectional torque mechanism <NUM> is a functional component of the defeatable unidirectional mechanism <NUM>. With concurrent reference to <FIG>, the unidirectional torque mechanism <NUM> is positioned in the frictional relationship with the chamber mount <NUM> that is fixed relative to the housing <NUM>, and the clutch mechanism <NUM> may be defined at the frictional interface (e.g., the unidirectional torque mechanism <NUM> "slips" relative to the chamber mount <NUM>). The clutch mechanism <NUM> is configured to permit rotation of the ratchet ring <NUM> (operably coupled to the first control surface <NUM>) in the first and second directions when the ratchet ring <NUM> receives a torque input exceeding the torque threshold sufficient to overcome the frictional relationship.

The ratchet ring <NUM> includes the inner surface <NUM> opposite the outer surface <NUM> to define the proximal portion <NUM> of the ratchet ring <NUM>. The ratchet ring <NUM> may also includes a distal portion <NUM> coupled to the proximal portion <NUM>. The distal portion <NUM> is positioned distally the proximal portion <NUM> and along the translation axis. Similar to the proximal portion <NUM>, the distal portion <NUM> may be generally ringshaped and defined between an inner annular surface <NUM> and an outer annular surface <NUM>, as shown in <FIG>, <FIG> and <FIG>. The outer annular surface <NUM> of the distal portion <NUM> may be in the frictional relationship with the chamber mount <NUM> to define the clutch mechanism <NUM>. One or more frictional elements <NUM> may be provided at the interface between the outer annular surface <NUM> and an inner surface of the proximal ring <NUM> of the chamber mount <NUM> (see <FIG> and <FIG>) to increase the frictional relationship to achieve a desired torque threshold. In other words, if a relatively greater frictional relationship is associated with the clutch mechanism <NUM>, the physician is required to provide a larger second input torque to the first control surface <NUM> to overcome the frictional relationship and move the lead screw <NUM> in the proximal direction along the translation axis. <FIG> and <FIG> show the frictional elements being an O-ring disposed within a recess within the outer annular surface <NUM> of the distal portion <NUM>. More than one O-ring may be provided. The O-ring(s) have a thickness slightly greater than a depth of the recesses in order to contact the inner surface of the chamber mount <NUM>.

The clutch mechanism <NUM> is configured to permit rotation of the first control surface <NUM> in the first and second directions in response to receiving the first and second torque inputs, respectively, exceeding the torque threshold, and the unidirectional torque mechanism <NUM> is adapted to permit for rotation of the first control surface <NUM> in the first direction, and prevent rotation of the first control surface <NUM> about the translation axis in the second direction. Thus, with the unidirectional torque mechanism <NUM> and the clutch mechanism <NUM> functionally integrated, the first control surface <NUM> may be rotatable in the first direction when the first input torque is below the torque threshold.

A first magnitude of the first input torque is required to be provided to the primary control surface <NUM> to overcome the force of the biasing members <NUM> biasing the pawl <NUM> as the pawl <NUM> passes the ratchet teeth <NUM> in the first direction, along with the forces associated with the curable material compressed within the dispensing volume <NUM>. A second magnitude of the first input torque defines the torque threshold associated with the clutch mechanism <NUM>. The first magnitude is less than the second magnitude. In other words, the frictional engagement defining the clutch mechanism <NUM> should never be overcome as the handle <NUM> is rotated in the first direction, since the pawl <NUM> is configured to much more easily move past the ratchet teeth <NUM>. In the second direction, however, the tip of the pawl <NUM> firmly engages the ratchet teeth <NUM>, and increasing application of the second input torque is insufficient to overcome the engagement. The second input torque is effectively transferred from the handle <NUM>, to the pawl <NUM>, then to the ratchet teeth <NUM> of the ratchet ring <NUM>. With continued increasing application of the second input torque, eventually the second input torque exceeds the torque threshold such that the frictional engagement of the clutch mechanism <NUM> is overcome and the ratchet ring <NUM> rotates relative to the chamber mount <NUM>, and thus relative to the housing <NUM>. The torque threshold may be two, three, five or time times greater than the first torque input required to rotate the handle <NUM> in the first direction. With the locking nut <NUM> in the engaged position, the second input torque above the torque threshold causes the lead screw <NUM> to move in the proximal direction relative to the locking nut <NUM>. The above disclosure delineates that the defeatable unidirectional mechanism <NUM> is advantageously configured to provide for the distal advancement of the lead screw <NUM> with the first input torque less than the torque threshold; prevent for the proximal movement of the lead screw <NUM> with the second torque input less than the torque threshold; and permit for the proximal movement of the lead screw <NUM> with the second torque input exceeding the torque threshold. Consequently, with the actuator <NUM> engaging the locking nut <NUM>, the physician may distally advance the plunger <NUM> within the dispensing volume <NUM> by rotating the handle <NUM> in the first direction with relative ease. The physician may release his or her hand to reset it (or for any other reason), and the handle <NUM> is prevented from rotating in the second direction by the defeatable unidirectional mechanism <NUM>. The physician may cause the proximal movement of the plunger <NUM> in two ways: releasing the secondary input force to the second control surface <NUM>, and/or rotating the handle <NUM> in the second direction with relative effort to overcome the frictional relationship.

In an alternative implementation, at least a portion of the defeatable unidirectional mechanism <NUM> may be rotatably fixed relative to the housing <NUM>. For example, the defeatable unidirectional mechanism <NUM> may include a friction ring is rotatably fixed relative to the housing <NUM> with the first control surface <NUM> is movable (e.g., rotatable) relative to the friction ring. In another alternative implementation, the trailing edge of the ratchet teeth <NUM> and the tip of the pawl <NUM> are complimentarily shaped so as to cause defeatable engagement such that the primary control surface <NUM> can be rotated in the second direction when the second torque input exceeds the torque threshold.

In view of the foregoing description of the curable material dispensing system <NUM>, methods of operating the system <NUM> are provided with reference to <FIG>. The system <NUM> may be operated by the physician including first hand (FH) and second hand (SH) each includes a palm (P) and an index finger (I), a middle finger (M), and a thumb (T) extending from the palm (see Figure <NUM>). The housing <NUM> may be supported in the palm of the second hand of the physician. The secondary input force is applied to the second control surface <NUM> to move the second control surface <NUM> from the disengaged position to the engaged position. The secondary input force may be provided while the second hand supports the housing <NUM>, such as with the index finger, middle finger, and/or the thumb of the second hand. The actuator <NUM> is moved into engagement with the locking nut <NUM> to prevent rotation of the locking nut <NUM> about the translation axis. The second control surface <NUM> is maintained in the engaged position against a force provided by the biasing member <NUM>. The second control surface <NUM> with the index finger, middle finger, and/or the thumb of the second hand while supporting the primary control surface <NUM> with the first hand.

With the second control surface maintained in the engaged position, the primary input force is provided to the first control surface <NUM>. The primary input force may be rotation provided by the index finger, middle finger, and/or the thumb of the first hand. The unidirectional torque mechanism permits the distal movement of the lead screw <NUM> with rotation of the first control surface <NUM> about the translation axis in the first direction with relative ease. The lead screw <NUM> moves distally along the translation axis to compress the curable material within the dispensing volume <NUM>. The physician may remove the secondary input force provided to the second control surface <NUM>. In particular, the index finger, middle finger and/or the thumb of the second hand may be removed from the second control surface <NUM> while supporting the housing <NUM> with the palm of the second hand, and while supporting the first control surface <NUM> with the first hand. The biasing member <NUM> resiliently moves the second control surface <NUM> from the engaged position to the disengaged position. The actuator <NUM> is moved out of engagement with the locking nut <NUM>. The locking nut <NUM> is now rotatable about the translation axis and provides for movement of the lead screw <NUM> in the proximal direction along the translation axis to permit the compressed curable material to at least partially decompress within the dispensing volume <NUM>.

According to another exemplary method of the curable material dispensing system <NUM>, the actuator <NUM> is initially biased into engagement with the locking nut <NUM> with a force provided by the biasing member <NUM>. In other words, without the secondary input force provided to the second control surface <NUM>, the locking nut <NUM> is rotatably fixed about the translation axis. The primary input force is provided to the first control surface <NUM> while the locking nut <NUM> is rotatably fixed with the actuator <NUM> in the engaged position. The secondary input force is applied to the second control surface <NUM> with the secondary input force being sufficient to overcome the force provided by the biasing member <NUM> and move the actuator <NUM> to the disengaged position. The locking nut <NUM> is now rotatable about the translation axis and provides for movement of the lead screw <NUM> in the proximal direction along the translation axis to permit the compressed curable material to at least partially decompress within the dispensing volume <NUM>. The secondary input force may be released from the second control surface <NUM>, after which the biasing member <NUM> returns the actuator <NUM> to the engaged position with the locking nut <NUM>. The threadable engagement between the internal threads <NUM> of the locking nut <NUM> and the external threads <NUM> of the lead screw provide for translation of the lead screw <NUM> distally along the translation axis to compress the curable material within the dispensing volume <NUM>. The compressed curable material is dispensed from the distal outlet <NUM> of the chamber <NUM> in communication with the dispensing volume <NUM>.

With continued reference to <FIG> and further reference to <FIG>, as previously mentioned, the extension tube <NUM> may be coupled to the distal coupler <NUM> of the chamber <NUM>. The extension tube <NUM> is adapted to be coupled to the surgical instrument secured within the patient, such as the access cannula penetrating bony anatomy. The extension tube <NUM> includes the elbow coupler <NUM>, and a flexible tube <NUM> rotationally and/or pivotally coupled to the elbow coupler <NUM>. The flexible tube <NUM> may be formed from flexible tubing, but it is contemplated that the flexible tube <NUM> may be of suitably rigid construction. It should be further appreciated that the components of the extension tube <NUM> are constructed so as to withstand pressures associated with dispensing the compressed curable material. For example, the extension tube <NUM> is constructed to withstand pressures of <NUM>,<NUM>, <NUM>,<NUM>, <NUM>,<NUM>, <NUM>,<NUM> or <NUM>,<NUM> or more bar (<NUM>, <NUM>, <NUM>, <NUM>, or <NUM> or more pounds per square inch (psi)).

The elbow coupler <NUM> may be adapted to removably couple with the distal coupler <NUM> of the curable material dispensing system <NUM>. With the elbow coupler <NUM> coupled to the distal coupler <NUM>, the elbow coupler <NUM> is in fluid communication with the distal outlet <NUM> and the dispensing chamber <NUM> of the system <NUM>. The elbow coupler <NUM> may be a relatively short, tubular or hollow structure that is rigid in construction. The flexible tube <NUM> is coupled to elbow coupler <NUM> to establish fluid communication between the flexible tube <NUM> and the dispensing chamber <NUM> of the system <NUM>.

The elbow coupler <NUM> is configured to articulate the flexible tube <NUM> relative to the elbow coupler <NUM> about a first axis A<NUM>, and the rotating coupler <NUM> is configured to articulate the flexible tube <NUM> relative to the elbow coupler <NUM> about a second axis A<NUM>, as shown in <FIG>. The second axis A<NUM> may be orthogonal to the first axis A<NUM>. Thus, with the flexible tube <NUM> in the manner described, the flexible tube <NUM> is articulable relative to the system <NUM> in at least two degrees of freedom (e.g., pivotable about the first axis A<NUM> and rotatable about the second axis A<NUM>). The extension tube <NUM> further includes a cannula coupler <NUM> coupled to the flexible tube <NUM>. The cannula coupler <NUM> is adapted to be removably coupled to the surgical instrument secured within the patient, for example, the access cannula, an interior of the bony anatomy is in fluid communication with the dispensing chamber <NUM> of the system <NUM>. For example, during a vertebroplasty procedure, the curable material may be dispensed the extension tube <NUM>, through the access cannula, and into the cancellous region of the vertebral body. The cannula coupler <NUM> is configured to rotate about a third axis A<NUM>, as illustrated in <FIG>. Thus, the extension tube <NUM> of the present disclosure provides for articulation of the curable material dispensing system <NUM> relative to the surgical instrument rigidly secured within the patient in at least three degrees of freedom (e.g., pivotable about the first axis A<NUM>, rotatable about the second axis A<NUM>, and rotatable about the third axis A<NUM>). Moreover, additional "quasi" degrees of freedom may be realized by the flexibility of the flexible tube <NUM> (i.e., the physician may reorient the system <NUM> relative to the surgical instrument by causing bending of the flexible tube <NUM> despite not having another "true" degree of freedom (e.g., prismatic joint). The extension tube <NUM> of the present disclosure advantageously provides the physician with improved maneuverability about the patient and the surgical site without placing undue stress on the surgical instrument rigidly secured within the patient. Further, in procedures where fluoroscopy is utilized, the physician is better able to maintain fluid communication between the system <NUM> and the interior the bony anatomy while avoiding unnecessary exposure to radiation. For example, the several degrees of freedom afforded by the extension tube <NUM> permits the physician to be separated from the surgical field by a screen while maintain control of the system <NUM> coupled to the patient.

A further advantage of the extension tube <NUM> of the present disclosure is realized during packaging, shipping, and/or storing of the system <NUM>. Known systems may require a flexible tube be installed on a dispensing system immediately prior to use, which consumes time and resources that could be diverted to other tasks associated with the surgical procedure. Alternatively, for flexible tubes preinstalled on the dispensing system, the packaging must be sufficiently large to accommodate the structures. Likewise, storage of the packaged dispensing system consumes an inordinate amount of space in, for example, a storage room. In either instance, the dispensing system with the flexible tubing consumes a substantial amount of tabletop space within the surgical suite and, more particularly, a large amount of space within the sterile field. The extension tube <NUM> of the present disclosure provides for a system and/or method of packaging the curable material dispensing system <NUM>. <FIG> shows a schematic representation of the curable material dispensing system <NUM>, the mixing and compression system <NUM>, and the extension tube <NUM> within packaging <NUM>. With concurrent reference to <FIG>, it is observed that the distal coupler <NUM> is at an angle, and in particular a right angle, relative to the chamber <NUM> oriented on the translation axis. Likewise, the elbow coupler <NUM>, as implied by its name, orients the flexible tube <NUM> at an angle relative to the coupling interface between the elbow coupler <NUM> and the distal coupler <NUM>. The resulting arrangement, shown in <FIG> and <FIG>, allows the flexible tube <NUM> to be articulated to a packaging configuration in which the chamber <NUM> of the curable material dispensing system <NUM> and the flexible tube <NUM> are substantially parallel. The extension tube <NUM> and the curable material dispensing system <NUM> are may be coupled to one another prior to packaging to be nestled closely to one another within the packaging <NUM> while providing the flexible tube <NUM> of sufficient length without requiring undesirably large packaging.

The curable material dispensing system <NUM> is provided, and the elbow coupler <NUM> is coupled to the distal coupler <NUM> of the chamber <NUM>, thereby establishing fluid communication between the cannula coupler <NUM> and the dispensing volume <NUM>. The extension tube <NUM> may be considered in a deployed configuration in which the chamber <NUM> and the elbow coupler <NUM> are substantially parallel and the flexible tube <NUM> is positioned away the dispensing volume <NUM> relative to the elbow coupler <NUM>. The deployed configuration is shown in <FIG>. In the deployed configuration the elbow coupler <NUM> and the flexible tube <NUM> may be offset. The flexible tube <NUM> is articulated about the elbow coupler <NUM> from the deployed configuration to the aforementioned packaging configuration in which the elbow coupler <NUM> and the flexible tube <NUM> are substantially parallel and the flexible tube <NUM> is positioned towards the dispensing volume <NUM> relative to the elbow coupler <NUM>. The packaging configuration is shown in <FIG>. In the packaging configuration, the flexible tube <NUM> may be positioned adjacent the housing <NUM>. Thereafter, the curable material dispensing system <NUM> and the extension tube <NUM> in the packaging configuration are positioned within the packaging <NUM> having dimensions sufficient to accommodate the curable material dispensing system <NUM> and the extension tube <NUM>. The packaging <NUM> may be a plastic housing that allows sterilant to enter and contact the various surfaces of the curable material dispensing system <NUM> and the extension tube <NUM>. The packaging <NUM> may be configured to maintain sterility of the curable material dispensing system <NUM> and the extension tube <NUM> disposed therein (e.g., hermetically sealed).

The extension tube <NUM> may remain in the packaging configuration after removal from the packaging <NUM>. Several benefits are realized with situating the curable material dispensing system <NUM> within the surgical suite with the extension tube <NUM> in the packaging configuration. Whether situated on a "back table" or a Mayo stand of the surgical suite, the curable material dispensing system <NUM> consumes significantly less space within the sterile field, space that may be reallocated to other surgical instruments and items required to be in the sterile field. Further, in practice known systems were often situated on the back table and Mayo stand with the flexible tubes extending over a perimeter of the table or stand. The portion of the flexible tube extending outside the sterile zone increases the risk of contact with unsterile objects, and increases the risk of being inadvertently knocked off the table or stand by personnel moving about the surgical suite. The curable material dispensing system <NUM> with the extension tube <NUM> of the present disclosure overcomes the aforementioned disadvantages. And once the dispensing chamber <NUM> receives the curable material and the system <NUM> is ready for use during the surgical procedure, the extension tube <NUM> may be quickly moved from the packaging configuration to the deployed configuration.

Claim 1:
A system (<NUM>) for dispensing curable material, the system (<NUM>) comprising:
a housing (<NUM>);
a chamber (<NUM>) coupled to the housing (<NUM>) and defining a dispensing volume (<NUM>) adapted to dispense the curable material;
a first control surface (<NUM>) coupled to the housing (<NUM>) and adapted to receive an input from a user;
a locking nut disposed within the housing (<NUM>) and comprising internal threads (<NUM>); and
a lead screw (<NUM>) rotatably fixed relative to the first control surface (<NUM>) with the lead screw (<NUM>) comprising a proximal end (<NUM>), a distal end (<NUM>), external threads (<NUM>) at least partially disposed between the proximal and distal ends (<NUM>, <NUM>), and a translation axis (TA) defined between the proximal and distal ends (<NUM>, <NUM>) with engagement between the external threads (<NUM>) of lead screw (<NUM>) and the internal threads of the locking nut (<NUM>) adapted to provide for movement of the lead screw (<NUM>) along the translation axis to compress the curable material within the dispensing volume (<NUM>); and
a defeatable unidirectional mechanism (<NUM>) operably coupling the first control surface (<NUM>) and the housing (<NUM>),
characterised in that the defeatable unidirectional mechanism (<NUM>) is adapted to (i) permit for distal advancement of the lead screw (<NUM>) in response to the first control surface (<NUM>) receiving a first input torque in a first direction (R1) about the translation axis that is below a torque threshold, (ii) prevent proximal movement of the lead screw (<NUM>) in response to the first control surface (<NUM>) receiving a second input torque in a second direction (R2) opposite the first direction that is less than the torque threshold, and (iii) permit proximal movement of the lead screw (<NUM>) with rotation of the first control surface (<NUM>) in the second direction in response to the first control surface (<NUM>) receiving the second input torque that is at least equal to the torque threshold.