Method of using expandable cannula
First Claim
1. A method comprising the steps of moving a leading end of a thin elongated member which extends through a cannula into a patient'"'"'s body tissue while a resilient sheath of the cannula is in a contracted condition and encloses a portion of the thin elongated member, moving at least a portion of the cannula and at least a portion of the thin elongated member into the patient'"'"'s body tissue through an opening which was at least partially formed by the leading end of the thin elongated member while the sheath of the cannula is in the contracted condition and encloses the thin elongated member, and withdrawing the thin elongated member from the sheath of the cannula while the sheath of the cannula is at least partially disposed in the patient'"'"'s body tissue, resiliently expanding the sheath of the cannula to an expanded condition by insetting a second member into the sheath of the cannula, said step of resiliently expanding the sheath of the cannula includes moving filaments enclosed by the sheath of the cannula relative to each other and increasing a cross sectional area of the cannula from a first size to a second size which is larger than the first size as viewed in a plane extending perpendicular to a longitudinal central axis of the cannula, wherein the opening increases in size with the resilient expansion of the sheath.
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Accused Products
Abstract
Cannulas for surgical and medical use expand along their entire lengths. The cannulas are inserted through tissue when in an unexpanded condition and with a small diameter. The cannulas are then expanded radially outwardly to give a full-size instrument passage. Expansion of the cannulas occurs against the viscoelastic resistance of the surrounding tissue. The expandable cannulas do not require a full depth incision, or at most require only a needle-size entrance opening. In one embodiment of the invention, the cannula has a pointed end portion. In this embodiment of the invention, the cannula includes wires having cores which are enclosed by jackets. The jackets are integrally formed as one piece with a sheath of the cannula. The cannula may be expanded by inserting members or by fluid pressure. The cannula is advantageously utilized to expand a vessel, such as a blood vessel. An expandable chamber may be provided at the distal end of the cannula.
237 Citations
25 Claims
- 1. A method comprising the steps of moving a leading end of a thin elongated member which extends through a cannula into a patient'"'"'s body tissue while a resilient sheath of the cannula is in a contracted condition and encloses a portion of the thin elongated member, moving at least a portion of the cannula and at least a portion of the thin elongated member into the patient'"'"'s body tissue through an opening which was at least partially formed by the leading end of the thin elongated member while the sheath of the cannula is in the contracted condition and encloses the thin elongated member, and withdrawing the thin elongated member from the sheath of the cannula while the sheath of the cannula is at least partially disposed in the patient'"'"'s body tissue, resiliently expanding the sheath of the cannula to an expanded condition by insetting a second member into the sheath of the cannula, said step of resiliently expanding the sheath of the cannula includes moving filaments enclosed by the sheath of the cannula relative to each other and increasing a cross sectional area of the cannula from a first size to a second size which is larger than the first size as viewed in a plane extending perpendicular to a longitudinal central axis of the cannula, wherein the opening increases in size with the resilient expansion of the sheath.
- 10. A method comprising the steps of moving a cannula having an open distal end and a resilient sheath into a patient'"'"'s body through a tissue opening while the sheath is in a contacted condition, and resiliently expanding the sheath of the cannula to an expanded condition by inserting a member into the sheath of the cannula, wherein said step of resiliently expanding the sheath of the cannula includes moving filaments enclosed by the sheath of the cannula relative to each other and wherein said step of inserting a member into the sheath includes stretching the tissue opening.
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19. A method comprising the steps of moving a cannula having a resilient sheath into a patient'"'"'s body through a tissue opening while the sheath is in a contracted condition, moving a pointed leading end of a thin elongated member into the sheath of the cannula while the sheath of the cannula is in the contacted condition, and resiliently expanding the sheath of the cannula to an expanded condition by inserting a member into the sheath of the cannula, said step of inserting a member into the sheath of the cannula includes expanding the tissue opening and said step of resiliently expanding the sheath of the cannula includes moving filaments enclosed by the sheath of the cannula relative to each other.
- 20. A method comprising the steps moving a cannula having a resilient sleeve with a central passage into a patient'"'"'s body tissue through a tissue opening with a thin elongated member disposed in the central passage in the resilient sleeve and with a leading end portion of the thin elongated member extending ahead of the resilient sleeve, withdrawing the thin elongated member from the central passage in the resilient sleeve while the resilient sleeve is disposed in the patient'"'"'s body tissue, and moving a dilator member into the central passage in resilient sleeve to expand the resilient sleeve while the resilient sleeve is disposed in the patient'"'"'s body tissue, said step of moving a dilator member into the central passage in the resilient sleeve to expand the resilient sleeve includes expanding the tissue opening and expanding an array of filaments enclosed by the resilient sleeve.
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22. A method as set forth in claim 26 wherein said step of withdrawing the thin elongated member from the central passage in the resilient sleeve is performed after moving the dilator member into the central passage in the resilient sleeve.
Specification