Sheath for maintaining position in a body cavity

A sheath for implanting a medical device or medical equipment into a body cavity of a patient, said sheath comprising:

• a sheath wall comprising at least one anchoring element disposed at a distal tip of the sheath, said anchoring element including a distal tip and a proximal tip,
• wherein:
• said anchoring element is in a form of a hinge or hook,
• said sheath wall is comprised of a memory-shape material or superelastic material that is pre-formed to cause the proximal tip of the hinge or hook to extend from a generally cylindrical surface of the sheath wall when not forced to remain substantially in a same shape as a remaining portion of the sheath wall by pressure exerted on the distal tip of the hinge or hook by a structure disposed within a lumen of the sheath,
• extension of the hinge or hook away from the generally cylindrical surface of the sheath wall creates an anchor having an anchoring function that retains the distal tip of the sheath within the body cavity by contact of the anchor with a surface of the body cavity while simultaneously extending the distal tip of the hinge or hook inwardly to extend over an opening of the lumen at the distal tip of the sheath, and
• contact of a mechanical element of sufficient diameter into the lumen of the sheath causes retraction of the hinge or hook, thus disabling the anchoring function of the anchor and allowing removal of the sheath from the body cavity without tearing of the surface of the body cavity.

A method of anchoring a sheath in a body cavity, comprising:

• inserting the sheath through a wall of the body cavity so that a distal portion of the sheath is located in the body cavity,
• wherein:
• the sheath includes a sheath wall extending from a proximal portion to the distal portion of the sheath, the sheath wall comprising one or more channels disposed within the sheath wall that traverse the sheath wall in a direction from the proximal portion to the distal portion of the sheath, wherein the one or more channels terminate adjacent the distal portion of the sheath with a first opening located below the distal portion of the sheath through which a distal tip of a wire anchor can be extended and retracted, and wherein the one or more channels terminate at or adjacent to the proximal portion of the sheath with a second opening through which a proximal portion of the wire anchor can be manipulated by an operator to extend and retract the wire anchor from and into the first opening, wherein the sheath is configured to be inserted through a wall of the body cavity so that the distal portion of the sheath and the first opening are located inside the body cavity above an inner surface of the wall of the body cavity, and
• the wire anchor is comprised of a memory-shape material or superelastic material that is pre-formed to comprise a curve or bend that is caused to straighten when disposed within the one or more channels, but allowed to reform its pre-formed curved or bent shape when not disposed within the one or more channels,
• pushing the proximal portion of the wire anchor at the second opening so that the wire anchor extends from the first opening initially in a first direction upward towards the distal portion of the sheath, but then curls downwards in an opposite second direction to engage the inner surface of the wall enclosing the body cavity as the operator pushes the proximal portion of the wire anchor at the second opening to push the distal tip of the wire anchor out of the first opening thus forming a wire anchor providing an anchoring function for the sheath on the inner surface of the wall that retains the distal portion of the sheath spaced above the inner surface of the wall within the body cavity by contact of the wire anchor with the inner surface of wall of the body cavity, and
• retracting the wire anchor, by the operator pulling on the proximal portion of the wire anchor at the second opening, into the one or more channels of the sheath wall to disable the anchoring function and remove the sheath from the body cavity without tearing tissue of the inner surface of the wall of the body cavity that the wire anchor was anchored to.