Medical device

A medical device comprising:

• an elongated outer sheath possessing a distal end;
• an inner member inside the outer sheath, the inner member possessing a distal end positioned distally of the distal end of the outer sheath, and the inner member being axially movable in an axial direction relative to the outer sheath;
• an expansion portion between the distal end of the outer sheath and the distal end of the inner member, the expansion portion comprising a plurality of linear material portions, the expansion portion being movable between a non-expanded position in which the linear material portions extend in the axial direction and an expanded position in which the linear material portions expand radially outwardly by virtue of the inner member moving proximally in a proximal direction relative to the outer sheath;
• a rotatable member rotatably positioned inside the outer sheath;
• a body connected to the outer sheath;
• a biasing member inside the outer sheath, the biasing member applying a biasing force to the rotatable member in the proximal direction so that the rotatable member is a spring-biased rotatable member;
• the rotatable member being rotatable inside the outer sheath between a first position in which the body prevents the biasing force from axially moving the inner member in the proximal direction, whereby the expansion portion remains in the non-expanded position, and a second position in which the spring-biased rotatable member applies the biasing force to the inner member to automatically axially move the inner member relative to the outer sheath in the proximal direction, whereby the expansion portion expands to the expanded position;
• and
• the inner member and the outer sheath being relatively axially movable so that the inner member moves in a distal direction to cause a part movable with the inner member to contact the rotatable member so that the rotatable member shifts from the first position to the second position, whereupon the biasing force of the biasing member is applied to the inner member to axially move the inner member in the proximal direction.

A method of treating a vein, the method comprising:

• inserting a medical device into the vein in a living body, the medical device comprising an elongated outer sheath possessing a distal end, an inner member inside the outer sheath and being axially movable in an axial direction relative to the outer sheath, the inner member possessing a distal end located distally of the distal end of the outer sheath, and an expansion portion between the distal end of the outer sheath and the distal end of the inner member, the expansion portion being expandable from a non-expanded position to an expanded position, and the inner member being prevented from proximal movement relative to the outer sheath when the medical device is inserted into the body with the expansion portion in the non-expanded position;
• moving the medical device to position the medical device at a desired location in the vein while maintaining the expansion portion in the non-expanded position;
• applying a force on the inner member to move the inner member distally in an axial direction relative to the outer sheath;
• removing the force on the inner member, and automatically axially moving the inner member in a proximal direction relative to the outer sheath upon removing the force;
• and
• outwardly expanding the expansion portion as a result of the inner member moving in the proximal direction relative to the outer sheath.