Patent Description:
The present invention relates to a surgical device and assembly and, more particularly, to a cannula seal assembly with a compatible flexible cannula.

Cannulas are used to support arthroscopic or endoscopic procedures by providing access to portals to the surgical site. Due to issues of fluid management, cannulas are often equipped with a seal at the proximal end. The seal limits fluid flow through the cannula, but may also contribute to the development of fluid pressure. Disturbing the seal by passing instruments or devices through the cannula may lead to spontaneous and uncontrolled projectile fluid leaks.

Further, traditional cannulas often have a rigid body with rigid threads. The rigid body maintains a tube-like structure for passing instruments and devices, while the rigid threads grab the tissue at the surgical site and provide fixation of the cannula. However, the rigid threads on cannula bodies can cause additional trauma and risk of injury at the surgical site when the cannula is inserted.

Therefore, there is a need for a cannula with flexible features for reducing injury and a seal assembly for controlling the outflow of fluid from a surgical site when passing instruments to the surgical site.

Description of the Related Art Section Disclaimer: To the extent that specific patents/publications/products are discussed above in this Description of the Related Art Section or elsewhere in this disclosure, these discussions should not be taken as an admission that the discussed patents/publications/products are prior art for patent law purposes. For example, some or all of the discussed patents/publications/products may not be sufficiently early in time, may not reflect subject matter developed early enough in time and/or may not be sufficiently enabling so as to amount to prior art for patent law purposes.

<CIT> discloses a cannula seal assembly with the features in the preamble of present claim <NUM>. Other conventional cannula seal assemblies are described in <CIT> and <CIT>.

The present disclosure is also directed to a cannula seal assembly with a compatible flexible cannula. The cannula includes a rigid cannula body having a proximal body end and distal body end. The cannula body is composed of material having a first thickness. A flexible thread extends along at least a portion of the cannula body from the distal body end toward the proximal body end. The thread is composed of material having a second thickness, which is less than a first thickness.

According to another aspect, the cannula includes a rigid cannula body having a proximal body end and a distal body end. A flexible sleeve extends along at least a portion of the cannula body from the distal body end toward the proximal body end. The cannula also includes a flexible thread extending along at least a portion of the sleeve.

The present invention will be more fully understood and appreciated by reading the following Detailed Description in conjunction with the accompanying drawings. The accompanying drawings illustrate only typical embodiments of the disclosed subject matter and are therefore not to be considered limiting of its scope, for the disclosed subject matter may admit to other equally effective embodiments. Reference is now made briefly to the accompanying drawings, in which:.

Aspects of the present invention and certain features, advantages, and details thereof, are explained more fully below with reference to the non-limiting examples illustrated in the accompanying drawings. Descriptions of well-known structures are omitted so as not to unnecessarily obscure the invention in detail. It should be understood, however, that the detailed description and the specific non-limiting examples, while indicating aspects of the invention, are given by way of illustration only, and are not by way of limitation. Various substitutions, modifications, additions, and/or arrangements, within the scope of the claims will be apparent to those skilled in the art from this disclosure.

Referring now to the figures, wherein like reference numerals refer to like parts throughout, <FIG> shows a partial sectional view schematic representation of a cannula <NUM>, according to an example which is not covered by the claimed scope but nevertheless useful to understand the present invention. The cannula <NUM> has a proximal end <NUM> and a distal end <NUM>. The distal end <NUM> is configured for insertion into a portal at a surgical site. A cannula body <NUM> extends from the proximal end <NUM> to the distal end <NUM> along a central longitudinal y - y axis. The cannula <NUM> additionally includes a port <NUM> extending from its proximal end <NUM>. The port <NUM> provides an exit for the flow of fluid from the cannula <NUM>. The port <NUM> includes a control valve (not shown) for allowing or prohibiting the flow of fluid through the port <NUM>. (The control valve would extend through a control valve aperture <NUM>, as understood by a person of ordinary skill in the art).

The cannula body <NUM> is elongated and tubular, having an open proximal body end <NUM> and an open distal body end <NUM> with an inner volume <NUM> extending therebetween. The inner volume <NUM> is sized and configured to accommodate surgical instruments and devices. In the depicted example, the distal body end <NUM> of the cannula body <NUM> is threaded such that a thread <NUM> extends proximally along at least a portion of an exterior surface <NUM> of the cannula body <NUM> from its distal body end <NUM>, as shown. The thread <NUM> functions as a fixation feature for anchoring the cannula <NUM> at the surgical site.

Turning now to <FIG>, there is shown a close-up sectional side view schematic representation of the thread <NUM>, according to an example. As shown, the thread <NUM> extends at an angle relative to the central longitudinal y - y axis. In particular, the thread <NUM> extends proximally (i.e., toward the proximal end <NUM> of the cannula <NUM>). The profile of the thread <NUM> is angled in the proximal direction, away from the direction of insertion. In an alternative example, the profile of the thread <NUM> can be angled in the distal direction, toward the direction of insertion.

Referring now to <FIG>, there is shown a close-up sectional side view schematic representation of the thread <NUM> in a compressed position, according to an example. As shown, the thread <NUM> is composed of flexible material such that the thread <NUM> yields under a predetermined compression force. In other words, a tip <NUM> of the thread <NUM> bends toward the exterior surface <NUM> of the cannula body <NUM> in the proximal direction (toward the central longitudinal y - y axis) to a compressed position. This bending in the proximal direction reduces the overall profile of the cannula <NUM> when it is compressed during insertion (i.e., when force is applied in the proximal direction by tissue). Thus, the smaller profile of the thread <NUM> during insertion minimizes interference.

Turning now to <FIG>, there is shown a close-up sectional side view schematic representation of the thread <NUM> in an expanded position, according to an example. Although the thread <NUM> is flexible, the thread <NUM> must be able to provide fixation at the surgical site. As shown in <FIG>, the thread <NUM> expands under tensile load (i.e., force in the distal direction) to maximize the overall profile of the cannula <NUM> during usage. Thus, the larger profile of the thread <NUM> during usage increases the fixation strength of the cannula <NUM> in the tissue at the surgical site. From the compressed position in <FIG>, the tip <NUM> of the thread <NUM> bends back slightly in the distal direction to an expanded position.

Referring now to <FIG> and <FIG>, there are shown close-up sectional side view schematic representations of the thread <NUM>, according to alternative example. In the examples shown in <FIG> and <FIG>, the geometry of the thread <NUM> allows for compression in the proximal direction and resistance to compression in the distal direction. In <FIG>, the thread <NUM> has different radii at a base <NUM> of the thread <NUM>. Specifically, the thread <NUM> has a first radius R<NUM> on distal side <NUM> of the base <NUM> and a second radius R<NUM> on a proximal side <NUM> of the base <NUM>. In the depicted example, the second radius R<NUM> is smaller than the first radius R<NUM>. With a smaller second radius R<NUM> on the proximal side <NUM>, the thread <NUM> is more susceptible to being compressed in the proximal direction D<NUM>. Similarly, with a larger first radius R<NUM> on the distal side <NUM>, the base <NUM> is more resistant to compression in the distal direction D<NUM>.

In <FIG>, the thread <NUM> has a reinforced base <NUM> that resists compression in the distal direction D<NUM>. In the depicted example, the thread <NUM> has a supporting feature <NUM>, such as a secondary thread, adjacent to the distal side <NUM> of the base <NUM> (or thread <NUM>). In <FIG>, the supporting feature <NUM> has a triangular cross-section. In particular, the supporting feature <NUM> is angled such that it is larger (or wider) closer to the thread <NUM>. The angle of the supporting feature <NUM> allows the tip <NUM> of the thread <NUM> to be compressed in the proximal direction D<NUM> (i.e., it does not interfere with force applied in the distal direction D<NUM>) and supports the base <NUM> of the thread <NUM> when force is applied to the thread <NUM> in the proximal direction D<NUM>. Furthermore, the supporting feature <NUM> is small enough that it does not extend past the thread <NUM> when the thread <NUM> is in the compressed position.

The combination of rigid and flexible features in the cannula <NUM> may be achieved using a single material or a combination of materials. The cannula <NUM> in <FIG> is composed of a single material. The combination of rigid and flexible features of the cannula <NUM> can be achieved by optimizing the material property of the substrate and the geometry of the cannula <NUM>. In the example of the cannula <NUM> shown in <FIG>, the cannula body <NUM> has a tube thickness t. The thickness t is large enough that the use of a flexible material can still create a rigid cannula body <NUM>. Similarly, the same material can be used for the flexible thread <NUM> by varying the thickness of the material. As shown in <FIG>, the thread <NUM> has a thickness t' that is small enough that the thread <NUM> is pliable. In the depicted example, the thickness t' of the thread <NUM> is less than the thickness t of the cannula body <NUM>.

Referring now to <FIG> and <FIG>, there are shown partial exploded and perspective views schematic representations of a cannula <NUM>, according to an alternative example. The cannula <NUM> shown in <FIG> and <FIG> is composed of a combination of materials. In other words, some features of the cannula <NUM> are composed of flexible material, while other features of the cannula <NUM> are composed of rigid material. As shown in <FIG>, the cannula body <NUM> is fabricated from or otherwise composed of a rigid material, which provides the structural strength of the cannula <NUM>.

On the other hand, the thread <NUM> is fabricated from or otherwise composed of a flexible material, which provides the pliability required for decreasing interference during insertion. In the example shown in <FIG> and <FIG>, the thread <NUM> is fabricated on a sleeve <NUM> composed of flexible material. The sleeve <NUM> is cannulated such that the sleeve <NUM> may be pulled over the cannula body <NUM> (i.e., the cannula body <NUM> extends through the sleeve <NUM>, as shown in <FIG>). This allows for a combination of materials to be used to achieve the same functionality of the cannula <NUM> in <FIG>.

Turning briefly to <FIG>, there is shown a partial interior view of the distal end <NUM> of the cannula <NUM> of <FIG> and <FIG>. When the rigid cannula body <NUM> is extended through the flexible sleeve <NUM>, the sleeve <NUM> extends distally past the distal body end <NUM> of the cannula body <NUM>. This additional length of the sleeve <NUM> is a compliant tip <NUM>, as shown in <FIG>. The compliant tip <NUM> protects the surgical site from unintentional injury.

Referring now to <FIG>, there is shown a partial interior side view schematic representation of a cannula seal assembly <NUM>, according to an embodiment. The assembly <NUM> is sized and configured for attachment to the proximal end <NUM> of a cannula <NUM> (such as that shown in <FIG> and <FIG>). The assembly <NUM> comprises a housing <NUM> having two seals positioned therein. The two seals include: one or more distal primary seals <NUM> and a proximal secondary seal <NUM>. As also shown in <FIG>, a reservoir <NUM> separates the primary seal <NUM> from the secondary seal <NUM>.

The primary seal <NUM> is the main seal within the assembly <NUM>. Fluid flows through the cannula <NUM> from the distal body end <NUM> of the cannula body <NUM> toward the primary seal <NUM>. When the primary seal <NUM> is undisturbed, it provides a barrier that limits fluid flow through the cannula <NUM>. When the primary seal <NUM> is disturbed (e.g., by a surgical instrument), fluid passes through the primary seal <NUM> and into the reservoir <NUM>. As shown in <FIG>, the reservoir <NUM> is a space between the primary and secondary seals <NUM>, <NUM>. Any projectile leakage bypassing the primary seal <NUM> is captured by the secondary seal <NUM>. The secondary seal <NUM> drastically reduces the amount of "splashing" experienced by the user. In particular, the secondary seal <NUM> serves as a splash guard because it does not withstand fluid pressure, but it captures projectile leakage.

Turning now to <FIG>, there is shown a partial interior perspective view schematic representation of the primary and secondary seals <NUM>, <NUM>, according to an embodiment. As shown, the separation of the primary seal <NUM> from the secondary seal <NUM> is maintained by a spacer <NUM>. The spacer <NUM> is composed of circular disks 112A, 112B with a central aperture <NUM> to avoid interference with the reservoir <NUM>. In the embodiment shown in <FIG>, the spacer <NUM> comprises a first circular disk 112A and a second circular disk 112B with one or more connectors <NUM> extending therebetween. The connectors <NUM> can be any piece or portion of rigid material that holds the first circular disk 112A at a distance from the second circular disk 112B, creating at least one transverse spacer slot <NUM> therebetween. The purpose of the spacer slot(s) <NUM> is to allow fluid to flow out from the reservoir <NUM>.

Over the course of use, the reservoir <NUM> between the primary seal <NUM> and the secondary seal <NUM> fills with fluid. The presence of low-pressure fluid in the reservoir <NUM> offers additional protection against projectile leakage. Any excess fluid will leak out from the reservoir <NUM> and through one or more transverse exterior slots <NUM> in an exterior wall <NUM> of the housing <NUM> (<FIG>), preventing fluid buildup between the primary and secondary seals <NUM>, <NUM>. The spacer slots <NUM> and the exterior slots <NUM> are transverse to a central longitudinal y - y axis extending through the cannula <NUM>. Specifically, the slots <NUM>, <NUM> extend in a direction along (or substantially parallel to) an x - x axis that is substantially perpendicular to the central longitudinal y - y axis and substantially parallel to the direction of the extension of the port <NUM> (<FIG>).

Referring now to <FIG>, there are shown various views schematic presentations of the cannula seal assembly <NUM>, according to an embodiment. To ensure that the reservoir <NUM> is consistently filled with fluid to aid in leakage protection, the assembly <NUM> comprises one or more chambers <NUM> extending around the reservoir <NUM>. As shown in <FIG>, the chambers <NUM> are concentric, extending at least partially around the reservoir <NUM>. In the depicted embodiment, the chamber <NUM> is created between the secondary seal <NUM> and the housing <NUM>. (Note, the housing <NUM> has been removed in <FIG> for clarity). Fluid levels between the primary and secondary seals <NUM>, <NUM> rise as fluid enters through the primary seal <NUM>. Eventually, fluid exceeds the volume of the reservoir <NUM> and flows out through the chamber <NUM>.

As shown in <FIG> and <FIG>, the assembly <NUM> also comprises one or more channels <NUM> extending around the reservoir <NUM>. In the depicted embodiment, the seals <NUM>, <NUM> are concentrically surrounded by an interior wall <NUM>. The interior wall <NUM> has one or more edges <NUM> extending therealong such that the edges <NUM> are between the interior wall <NUM> and the housing <NUM>. The edges <NUM> create the channels <NUM> extending around the reservoir <NUM>. In the depicted embodiment, the edge <NUM> and resulting channel <NUM> extend only partially around the reservoir <NUM>. In addition, the channel <NUM> shown in <FIG> and <FIG> is offset from the chamber <NUM> to ensure that the water level of the outflow always exceeds the height of the spacer <NUM>.

Specifically, <FIG> shows the fluid path p out of the chamber <NUM>. <FIG> shows the fluid path p out of the chamber <NUM> and into the channel <NUM>. Fluid levels must exceed the peak before flowing out of the assembly <NUM>. The offset configuration of the chamber <NUM> and the channel <NUM> in <FIG> ensures that a robust layer of fluid remains over the primary seal <NUM> in the reservoir <NUM>. Ultimately, the configuration of the spacer <NUM> and seals <NUM>, <NUM> allows the reservoir <NUM> to prime with fluid over the course of usage.

Claim 1:
A cannula seal assembly (<NUM>), comprising:
a housing (<NUM>) having a primary seal (<NUM>) and a secondary seal (<NUM>) therein;
a spacer (<NUM>) to maintain separation of the primary seal (<NUM>) from the secondary seal (<NUM>); and
a reservoir (<NUM>) which is a space between the primary seal (<NUM>) and the secondary seal (<NUM>) to collect fluid bypassing the primary seal (<NUM>) when the primary seal (<NUM>) is disturbed by a surgical instrument,
characterized by one or more transverse spacer slots (<NUM>) extending through the spacer (<NUM>) and into the reservoir (<NUM>).