Patent Description:
This document pertains generally, but not by way of limitation, to a system for and related methods of piercing an articular capsule.

Synovial joints have an articular capsule that surrounds the cartilage separating the bone ends and defines a synovial cavity that contains synovial fluid. The cartilage and other tissue within the synovial cavity can become damaged through overuse or injury requiring resection and removal of the damaged tissue. The damaged tissue can be removed by inserting a blade into the synovial cavity to resect the damaged tissue within the synovial cavity.

An arthroscopic procedure is frequently used to puncture the capsule tissue and provide an opening through which the blade can be inserted into the synovial cavity. The blade is typically set at an appropriate depth with an arthroscopic camera positioned within the synovial cavity. A switching stick or a Kirschner wire ("K-wire") is inserted through the exterior tissue and to the desired depth within the synovial cavity as visually confirmed by the arthroscopic camera. The switching stick can be used to guide a cannula inserted over the switching stick through the tissue wall into the synovial cavity. The switching stick can then be removed through the cannula and a blade can be inserted through the cannula, where the cannula protects the tissue wall of the synovial cavity from the blade as the blade is inserted within the synovial cavity. The cannula can be partially or entirely removed from the synovial cavity to unsheathe the cavity, which can be then maneuvered to resect the damaged tissue. The cannula can then be reinserted into the synovial cavity and the blade withdrawn through the cannula. After the blade is withdrawn, the switching stick can be reinserted into the cannula to guide removal of the cannula from the body.

A drawback of this approach is that the exposed blade can inadvertently damage healthy tissue by the fully exposed blade as the blade is maneuvered within the synovial cavity to cut the damaged tissue. Similarly, maneuvering of the cannula to unsheathe and sheathe the blade can cause unnecessary damage to the tissue wall. A related drawback is that the blade is often very thin to be passed through the cannula and can often break off during the resecting of damaged tissue. If the broken off portion of the blade cannot be retrieved through an arthroscopic procedure, a conventional invasive procedure that forms a larger opening the articular capsule could be required to retrieve the broken blade portion. Both the additional arthroscopic procedure and the conventional invasive procedure creates considerable risk for the patient and cause unnecessary damage to the healthy tissue.

<CIT> discloses an obturator that provides access to a joint through a capsule surrounding the joint. A distal end of the obturator has a first distal location with a first width dimension and a second distal location with a second width dimension, wherein the second distal location is proximal to the first distal location and the second width dimension greater than the first width dimension. A retractable blade can extend from the obturator to be exposed between the first distal location and the second distal location.

<CIT> discloses instruments for use in minimally invasive carpal tunnel release including a cannula and a cutting member movable longitudinally within the cannula to advance a cutting blade of the cutting member along a longitudinal slot in the cannula to sever a transverse carpal ligament disposed over the slot. A dilating member is provided for creating a subligamentous space to accommodate the cannula and/or for removing adhered synovium from a lower surface of the ligament.

<CIT> discloses a surgical instrument for endoscopic treatment that has viewing optics and a tubular member in which a cutting tool can be moved and tilted out beyond a diameter of the tubular member.

The present inventors have recognized, among other things, that a problem to be solved can include safely delivering a blade to within a synovial cavity and minimizing risk of a broken or damaged blade. In an example, the present subject matter can provide a solution to this problem, such as by positioning the blade within an inner lumen of a cannula having a cutting port. The blade can be moved within the cannula between a deployed position in which the blade is positioned within the cutting port to permit cutting of tissue through the cutting port and a retracted position in which the blade is pulled away from the cutting port to prevent inadvertent cutting of tissue through the cutting port. The cutting port is positioned in a radial wall of the cannula such that the cannula end is partially closed thereby reducing the risk of a broken portion of the blade becoming lost within the synovial cavity. In at least one example, the partially closed end of the cannula can shield the surrounding tissue from the blade preventing cutting of tissue by the blade except through the cutting port.

In accordance with the present invention, there is provided a system as set out in claim <NUM>.

As depicted in <FIG>, a capsule cutter <NUM>, according to the present invention includes a cannula assembly <NUM> and a blade assembly <NUM> having at least one blade <NUM> (referred to as "the blade <NUM>" or "each blade <NUM>" herein). The blade assembly <NUM> can be partially inserted into the cannula assembly <NUM> such that each blade <NUM> can be positioned within a cannula <NUM> of the cannula assembly. The blade assembly <NUM> can be actuated to move each blade <NUM> between a deployed position and a retracted position. In the deployed position, each blade <NUM> can be positioned within a cutting port <NUM> of the cannula <NUM> such that tissue can pass through the cutting port <NUM> for cutting with the corresponding blade <NUM>. In the retracted position, each blade <NUM> can be positioned away from the cutting port <NUM> to avoid cutting any tissue that enters the cutting port <NUM>. In at least one example, the blade assembly <NUM> can be configured such that each blade <NUM> can be initially positioned at the retracted position when the blade assembly <NUM> can be inserted into the cannula assembly <NUM>.

As depicted in <FIG>, <FIG>, and <FIG>, the cannula assembly <NUM> includes a cannula <NUM> having a distal end <NUM> and a proximal end <NUM> and defining at least one internal lumen <NUM> extending from the distal end <NUM> to the proximal end <NUM>. The cannula <NUM> defines at least one cutting port <NUM> for accessing the internal lumen <NUM>. In an example, the cutting port <NUM> can be positioned on a side wall of the cannula <NUM> between the distal end <NUM> and the proximal end <NUM>. According to the present invention, the cutting port <NUM> is positioned on a side wall of the cannula <NUM> proximal the distal end <NUM>. The cannula <NUM> includes a guide port <NUM> positioned at the distal end <NUM> and defining a proximal opening of the internal lumen <NUM>. In an example, the guide port <NUM> can be aligned with a longitudinal axis A-A defined by the internal lumen <NUM> of the cannula <NUM>. The cannula <NUM> includes an access port <NUM> proximal the proximal end <NUM>. In an example, the access port <NUM> can be aligned with the longitudinal axis A-A.

As depicted in <FIG>, <FIG>, and <FIG>, the cannula assembly <NUM> can include a handle portion <NUM> positioned proximal the proximal end <NUM> of the cannula assembly <NUM>. In an example, the handle portion <NUM> can define the access port <NUM> of the internal lumen <NUM>. The handle portion <NUM> can be gripped by an operator for positioning and reorienting the cannula <NUM>. In an example, the handle portion <NUM> can define an engagement feature <NUM> for attachment of the blade assembly <NUM> to the proximal end <NUM> of the cannula assembly <NUM>.

As depicted in <FIG>, the blade assembly <NUM> includes the blade <NUM>, a base <NUM>, and a shaft <NUM> extending between the blade <NUM> and the base <NUM>. The blade <NUM> is insertable into the internal lumen <NUM> through the access port <NUM>. In an example, the shaft <NUM> can be sized such that the blade <NUM> can be proximate the cutting port <NUM> when the blade <NUM> can be inserted through the access port <NUM> and the base <NUM> engages the cannula assembly <NUM>. In an example, the base <NUM> can include a releasable engagement feature <NUM> corresponding to the engagement feature <NUM> of the handle port <NUM> to releasably attach the blade assembly <NUM> to the cannula assembly <NUM> when the blade <NUM> can be inserted into the internal lumen <NUM>.

As depicted in <FIG> and <FIG>, in an example, the shaft <NUM> can be slidably received within a channel <NUM> defined by the base <NUM> such that the shaft <NUM> can be slidable relative to the base <NUM> to move the blade <NUM> between a retracted position and a deployed position. As depicted in <FIG>, in the retracted position, the blade <NUM> can be moved away from the cutting port <NUM> such that the blade <NUM> can be primarily received within the internal lumen <NUM>. In this configuration, the cannula <NUM> protects the surrounding tissue from the blade <NUM>. As depicted in <FIG>, in the deployed position, the blade <NUM> can be moved into the cutting port <NUM> such that a portion of the blade <NUM> can be exposed through the cutting port <NUM>.

In an example, the shaft <NUM> can include a button <NUM> that can be manipulated to move the blade <NUM> between the retracted and deployed positions. In at least one example, the base <NUM> can include a spring <NUM> positioned within the channel <NUM> to bias the shaft <NUM> toward the retracted position. In this configuration, the blade assembly <NUM> can be attached to the cannula assembly <NUM> and the blade <NUM> inserted into the internal lumen <NUM> such that the blade <NUM> can be initially positioned in the retracted position. Upon manipulation by the operator, the blade <NUM> can be moved to the deployed position in order to position the blade <NUM> for cutting.

As depicted in <FIG> and <NUM>, a method <NUM> for cutting tissue, not forming part of the claimed invention, within a synovial cavity can comprise guide insertion and positioning <NUM>; cannula insertion over guide <NUM>; blade insertion into cannula <NUM>; blade deployment into cutting portion of the cannula <NUM>; and tissue cutting procedure <NUM>.

As depicted in <FIG>, the guide insertion and positioning <NUM> can include insertion of a K-wire <NUM>, switching stick or other guide element into the synovial cavity. The K-wire <NUM> can be inserted such that a distal end <NUM> of the K-wire <NUM> can be positioned to a pre-determined depth within the synovial cavity. As illustrated in <FIG>, in an example, the pre-determined depth can be sufficient to such that the cutting port <NUM> is fully within the synovial cavity when the cannula <NUM> can be inserted into the synovial cavity along the K-wire <NUM> and such that the distal end <NUM> of the cannula <NUM> approximate the distal end <NUM> of the K-wire <NUM>.

As depicted in <FIG>, cannula insertion over guide <NUM> can include feeding a proximal end <NUM> of the K-wire <NUM> into the guide port <NUM> of the cannula <NUM> and inserting the cannula <NUM> through the tissue along the K-wire <NUM>. In this configuration, the longitudinal axis A-A of the cannula <NUM> is generally parallel to the K-wire <NUM> as the cannula <NUM> is inserted through the tissue. In an example, the cannula <NUM> can be inserted such that the distal end <NUM> of the cannula <NUM> approximate the distal end <NUM> of the K-wire <NUM>.

As depicted in <FIG>, the blade insertion into cannula <NUM> can include insertion of the blade <NUM> and at least a portion of the blade shaft <NUM> of blade assembly <NUM> through the access port <NUM> in the handle assembly <NUM>. In an example, the releasable attachment feature <NUM> of the blade assembly <NUM> can be engaged to the attachment feature <NUM> to attach the blade assembly <NUM> to the handle assembly <NUM>. In an example, the blade shaft <NUM> can be sized such that the blade <NUM> can be initially positioned in the retracted position when the blade assembly <NUM> can be attached to the handle assembly <NUM> as depicted in <FIG>. In at least one example, the K-wire <NUM> can be removed from the tissue by drawing the K-wire <NUM> from the cannula <NUM> through the access port <NUM> prior to the insertion of the blade assembly <NUM>.

As depicted in <FIG>, the blade deployment <NUM> can include manipulating the button <NUM> of the blade shaft <NUM> to move the blade <NUM> axially such that the blade <NUM> can be moved into the deployed position and positioned within the cutting port <NUM>. In an example, the spring <NUM> can be compressed as the blade <NUM> is moved into the deployed position such that the spring <NUM> biases the blade <NUM> toward the retracted position when the blade <NUM> is released.

In the tissue cutting procedure <NUM>, the handle <NUM> can be manipulated to move the distal end <NUM> of the cannula <NUM> and the blade <NUM> contained therein to position tissue within the cutting port <NUM> for cutting with the blade <NUM>. In an example, the button <NUM> can remain depressed while the tissue is being cut and released to retract the blade <NUM> when tissue cutting is completed.

The drawings show, by way of illustration, specific embodiments in which the present subject matter can be practiced.

In the event of inconsistent usages between this document and any documents so referenced, the usage in this document controls.

Further, in an example, the code can be tangibly stored on one or more volatile, non-transitory, or nonvolatile tangible computer-readable media, such as during execution or at other times.

The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim.

Claim 1:
A system (<NUM>) for cutting tissue within a synovial cavity, comprising:
a cannula (<NUM>) defining an internal lumen (<NUM>) extending from a proximal end (<NUM>) to a partially closed distal end (<NUM>) and defining a cutting port (<NUM>) positioned in a radial side wall of the cannula (<NUM>) proximal to the distal end (<NUM>), an access port (<NUM>) in the proximal end (<NUM>) of the cannula and a guide port (<NUM>) in the distal end (<NUM>) of the cannula (<NUM>), all for accessing the internal lumen (<NUM>); and
a blade assembly (<NUM>) including a blade (<NUM>) and a blade shaft (<NUM>) extending from the blade, wherein the blade (<NUM>) is insertable into the internal lumen (<NUM>) of the cannula (<NUM>) through the access port (<NUM>) in the proximal end of the cannula (<NUM>) such that the blade is positioned adjacent the cutting port (<NUM>), wherein the blade shaft (<NUM>) is operable to move the blade (<NUM>) within the internal lumen (<NUM>) relative to the cutting port (<NUM>) between a retracted position and a deployed position,
wherein the blade (<NUM>) is received within the internal lumen (<NUM>) in the retracted position and the blade is positioned within the cutting port in the deployed position such that tissue can pass through the cutting port (<NUM>) for cutting with the blade and
wherein the system further comprises a guide element (<NUM>), the guide element (<NUM>) configured to be received in the guide port (<NUM>) in the distal end (<NUM>) of the cannula to align the cannula with the guide element (<NUM>).