Patent ID: 12239351

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference to the accompanying drawings.

The present disclosure provides for a cement mixing and delivery system that utilizes power mixing and reduces or eliminates air in the bone cement without the use of vacuum. The present disclosure further provides for a cement mixing and delivery system that can, for example and without limitation, utilize distributive mixing to uniformly disperse bone cement components and to simultaneously reduce or eliminate the presence of air within the bone cement.

In examples illustrated inFIGS.1A-3B, a bone cement mixing and delivery device100can comprise a cylindrical container102, a plug104, a mixing screw106, a mixing rod108, and an injection rod110. The cylindrical container102can include a proximal end112, a distal end114, a chamber116extending along a longitudinal axis118from the proximal end to the distal end thereof, and an injection passage120disposed at the distal end of the cylindrical container102. The mixing screw106can be rotatably disposable in the chamber102. The injection passage120can include an inner diameter that can be less than a diameter of the chamber116. The plug104can be removably disposable in the injection passage120. The device100can also include a lid136engageable with the proximal end112of the cylindrical container102, the lid136including an aperture138disposed therein through which at least one of the mixing screw106, the mixing rod108, and the injection rod110extend. As discussed in detail below, the mixing rod108engages the top of the mixing screw106, but leaves the central bore of the mixing106open to allow part of the mixing action to occur. In contrast, the injection rod110extends the length of the mixing screw106to enable ejection of the mixture via the injection passage120.

FIGS.2A and2Bare exploded views showing the cylindrical container102, the mixing screw106, the mixing rod108, the injection rod110, and the lid136. The mixing screw106can include a proximal end122, a distal end124, a screw thread126extending along an outer surface of the mixing screw106from proximate the proximal end122to proximate the distal end124of the mixing screw106, and a return passage128(seeFIG.1A) extending through the mixing screw106from the proximal end to the distal end thereof, Returning toFIGS.1A and1B, the mixing screw106can include a first void130disposed in and extending through a portion of a sidewall of the mixing screw106proximate one of the proximal end122and the distal end124of the mixing screw106and a second void132disposed in and extending through a portion of a sidewall of the mixing screw106proximate an opposite end of the screw from the first void130. The first void130and the second void132are connected by the return passage128. The mixing screw106can rotate in the same direction in both a mixing mode and an injection mode of the device100. The bone cement mixing and delivery device100is assembled in a mixing configuration by ensuring the plug104is engaged in the injection passage120, engaging the mixing screw106in the chamber102, adding the bone cement components to the chamber102, securing the lid136, and engaging the mixing rod108with the proximal end122of the mixing screw106. The bone cement mixing and delivery device100is converted from the mixing configuration to the injection configuration by removing the mixing rod108from the proximal end122of the mixing screw106, inserting the injection rod110into the return passage128of the mixing screw so that the first void130and the second void132are occluded, and removing the plug104from the injection passage120.

As illustrated inFIGS.1A, the mixing rod108can be selectively engageable with the proximal end122of the mixing screw106. Prior to initiating a mixing mode of the device100, the components of the bone cement can be loaded into the cylindrical chamber102as further indicated inFIG.3A. In the mixing mode of the device100further illustrated inFIG.3B, the mixing rod108can engage and rotate the mixing screw106about the longitudinal axis118of the cylindrical container102causing material disposed in the chamber116to be moved distally through the chamber by the screw thread126and return to the proximal end112of the chamber116(or cylindrical container102) through the return passage123of the mixing screw106as further described below.

As illustrated inFIG.1B, the injection rod110can be selectively inserted through the proximal end122of the mixing screw106and extendable through to engage the return passage128to a point proximate the distal end124of the mixing screw106. In an injection mode of the device100, the plug104can be removed from the injection passage120and a solid portion of the injection rod110can occlude the return passage128of the mixing screw106. The injection rod110can engage and rotate the mixing screw106about the longitudinal axis118causing material disposed in the chamber116to be moved distally through the chamber and through the injection passage120as further described below.

In one example, the distance from a thread root to a thread crest of the screw thread126can decrease over at least a portion of a length of the mixing screw106as the screw thread126extends from the proximal end122to the distal end124of the mixing screw106. Additionally or alternatively, a distance between adjacent turns of the mixing thread106can decrease from the proximal end122to the distal end124of the mixing screw106. The chamber116of the cylindrical container102can include a diameter that decreases distally from a first value to a second value over at least a portion of a length thereof. In one example, at least a distal portion of the cylindrical container can curve inward so as have the shape of a curved funnel. In operation, adjacent turns of the screw thread126can progressively compress material disposed in the chamber116as the screw thread126moves material from the proximal end112towards the distal end114of the cylindrical container102, thereby eliminating any air in and dispersing the components of the mixture.

In another example, the chamber116of the cylindrical container102can comprise a chamber thread140extending along at least a portion of the length of the chamber116. The chamber thread140can cooperate with the screw thread126to facilitate dispersion of mixture components and distal movement of material disposed in the chamber116. In an additional or alternative example, the coefficient of friction of the surface of the mixing screw106can be lower than a coefficient of friction of the surface of the chamber116. The lower coefficient of friction of the mixing screw106relative to the surface of the chamber1166can create turbulence during compression of the cement mixture by allowing the mixture to move faster at the inner diameter of the screw thread126and decelerating towards the outer diameter of the screw thread126(near the surface of the chamber116). Such turbulence can increase the efficiency of the distributive mixing process.

In an additional or alternative example, either or both of the screw thread126and the chamber thread140can comprise a substantially triangular thread form. The substantially triangular thread form can be a triangle including at least one of a flat thread crest and a rounded transitional surface between either or both of the proximal and distal thread roots. For example and without limitation, such a thread form can reduce or eliminate any dead zones that would otherwise be present in the mixing system.

Either or both of the Mixing rod and the injection rod can be actuated by, for example and without limitation, a user, a manual crank, an electric motor, a surgical drill, a robotic arm, and the like.

The various examples of bone cement mixing and delivery devices of the present disclosure can be used to mix a liquid component and a powder component. For example and without limitation, the bone cement can comprise polymethyl methacrylate (PMMA), and the like.

In an example, as illustrated inFIG.4, the present disclosure provides for a method400including steps for mixing and dispensing a bone cement mixture. The method400can comprise steps such as: loading bone cement components into a mixing chamber at410, engaging a lid at420, engaging a mixing rod with a mixing screw at430, mixing the bone cement at440, removing the mixing rod at450, engaging an injection rod at460, removing a plug at470, and dispensing the mixture at480.

In this example, the method400can begin at410with a user loading bone cement components (such as a monomer and a powder) into the cylindrical container102of a bone cement mixing and delivery device100through the proximal end112of the cylindrical container102. In some examples, the bone cement components can include powder components comprising, for example and without limitation, one or more of pre-polymerized PMMA, PMMA or methyl methacrylate (MMA) co-polymer beads and/or amorphous powder, radio-opacifer and initiator. In some examples, the bone cement components can include liquid components comprising, for example and without limitation, one or more of an MMA monomer, stabilizer, and inhibitor. At420, the method400can continue with the user engaging a lid136with the proximal end112of the cylindrical container102to remain the mixture components and prepare for mixing. At430, the method400can continue with the user inserting a mixing rod108through an aperture138disposed in the lid136to engage the proximal end122of the mixing screw126. At440, the method400continues with the user initiating the mixing process by rotating the mixing screw106via the mixing rod108to mix the bone cement components to form a bone cement mixture. As discussed above, the interaction between the mixing screw106and the cylindrical container102through rotation of the mixing rod108results in a mixing process that operates to eliminate air captured in the mixture (see discussion ofFIG.5Abelow). At450, the method400continues with the user completing the mixing process by removing the mixing rod106.

Once the mixing process is competed, the method400can continue at460with the user preparing for dispensing the mixture by inserting an injection rod110through the aperture138and the proximal end122of the mixing screw106to engage a return passage128extending through the mixing screw106proximate the distal end124of the mixing screw. At470, the method400continues with the user removing a plug104disposed in an injection passage120disposed at the distal end114of the cylindrical container102. Removing the plug104will allow the mixture to be dispensed upon rotation of the injection rod110. At480, the method400can complete with the mixture being dispensed by rotation of the mixing screw106via the injection rod110, which selectively dispenses bone cement mixture (see discussion ofFIG.5Bbelow).

As further illustrated inFIG.5A, rotating the mixing screw106via the mixing rod108to mix the bone cement components to form a bone cement mixture can further comprise cyclically urging the bone cement mixture in the chamber116along mixing pathway A from the proximal end112towards the distal end114of the cylindrical container102via at least one of the screw thread106disposed on the mixing screw106and the chamber thread140disposed on an inner surface of the chamber116; urging the bone cement mixture through a second void132disposed at the distal end124of the mixing screw106, through the return passage128, through the first void130into the chamber116proximate the proximal end112of the cylindrical container.

As further illustrated inFIG.5B, rotating the mixing screw106via the injection rod110to selectively dispense the bone cement mixture can further comprise urging the bone cement mixture in the chamber116along injection pathway B from the proximal end112towards the distal end114of the cylindrical container102and through the injection passage120via at least one of the screw thread106disposed on the mixing screw106and the chamber thread140disposed on an inner surface of the chamber116.

VARIOUS NOTES & EXAMPLES

Example 1 is a device comprising a cylindrical container, a plug, a mixing screw, a mixing rod, and an injection rod. The cylindrical container can include a proximal end, a distal end, a chamber extending along a longitudinal axis from the proximal end to the distal end, and an injection passage disposed at the distal end of the cylindrical chamber. The injection passage can include an inner diameter that can be less than a diameter of the chamber. The plug can be removably disposable in the injection passage. The mixing screw can be rotatably disposable in the chamber and can include a proximal end, a distal end, a screw thread extending along an outer surface of the mixing screw from proximate the proximal end to proximate the distal end of the mixing screw, and a return passage extending through the mixing screw From the proximal end to the distal end thereof. The mixing rod can be selectively engageable with the proximal end of the mixing screw. In a mixing mode of the device, the mixing rod can engage and rotate the mixing screw about the longitudinal axis of the cylindrical container causing material disposed in the chamber to be moved distally through the chamber by the screw thread and return to the proximal end of the chamber through the return passage of the mixing screw. The injection rod can be selectively engageable with the mixing screw and extendable through the return passage to a point proximate the distal end of the mixing screw. In an injection mode of the device, the plug can be removed from the injection passage and the injection rod can occlude the return passage of the mixing screw. The injection rod can engage and rotate the mixing screw about the longitudinal axis causing material disposed in the chamber to be moved distally through the chamber and through the injection passage.

In Example 2, the subject matter of Example 1 optionally includes wherein the mixing screw can include a first void disposed in and extending through a portion of a sidewall of the mixing screw proximate one of the distal end and the proximal end of the screw.

In Example 3, the subject matter of Example 2 can optionally include wherein the mixing screw can include a second void disposed in and extending through a portion of a sidewall of the mixing screw proximate an opposite end of the screw from the first void.

In Example 4, the subject matter of any one or more of Examples 1-3 can optionally include a lid engageable with the proximal end of the cylindrical container, the lid including an aperture disposed therein through which at least one of the mixing screw, the mixing rod, and the injection rod extend.

In Example 5, the subject matter of any one or more of Examples 1-4 can optionally include wherein the chamber of the cylindrical container has an inner diameter that decreases distally from a first value proximate a first location towards the proximate end to a second value proximate a second location towards the distal end, the decrease in diameter occurring over at least a portion of a length of the chamber.

In Example 6, the subject matter of Example 5 optionally includes wherein the chamber can be curved inward over at least a portion of the length thereof.

In Example 7, the subject matter of any one or more of Examples 1-6 can optionally include wherein the mixing screw can rotate in a single direction in both the mixing mode and the injection mode.

In Example 8, the subject matter of any one or more of Examples 1-7 can optionally include wherein the distance from a thread root to a thread crest of the screw thread can decrease over at least a portion of a length of the mixing screw as the screw thread extends from the proximal end to the distal end of the mixing screw.

In Example 9, the subject matter of any one or more of Examples 1-8 can optionally include wherein the screw thread comprises a substantially triangular thread form.

In Example 10, the subject matter of any one or more of Examples 1-9 can optionally include wherein a distance between adjacent turns of the screw thread can decrease from the proximal end to the distal end of the mixing rod.

In Example 14, the subject matter of Example 10 can optionally include wherein adjacent turns of the screw thread progressively compress material disposed in the chamber as the screw thread moves the material from the proximal end towards the distal end of the cylindrical container.

In Example 12, the subject matter of any one or more of Examples 1-11, can optionally include wherein the cylindrical container comprises a chamber thread extending from an inner sidewall along at least a portion of the length of the chamber.

In Example 13, the subject matter of Example 12 can optionally include wherein the chamber thread can cooperate with the screw thread to facilitate distal movement of material disposed in the chamber.

In Example 14, the subject matter of any one or more of Examples 12-13 can optionally include wherein the chamber thread comprises a substantially triangular thread form.

In Example 15, the subject matter of any one or more of Examples 1-14 can optionally include a surgical motor for selectively actuating the mixing rod and the injection rod.

In Example 16, the subject matter of any one or more of Examples 1-14 can optionally include a manual crank for selectively actuating the mixing rod and the injection rod.

In Example 17, the subject matter of any one or more of Examples 1-14 can optionally include a robotic arm for selectively actuating the mixing rod and the injection rod.

In Example 18, the subject matter of any one or more of Examples 1-17 can optionally include wherein a coefficient of friction of the surface of the mixing screw can be lower than a coefficient of friction of the surface of the chamber.

Each of these non-limiting examples can stand on its own, or can be combined in various permutations or combinations with one or more of the other examples. In the examples, the terms “a” and “the” are used interchangeably, such that reference to “the plate” in a given example can refer to a plate described in a previous example that is optionally combined with the given example, or can refer to a separate tether entirely. Similarly “a plate” can refer to a newly introduced plate, or to a plate described in a previous example.

The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention can be practiced. These embodiments are also referred to herein as “examples,” Such examples can include elements in addition to those shown or described. However, the present inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the present inventors also contemplate examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be comprised within the scope of the disclosure.