Trocar cannula assembly with low profile insertion configuration and method of manufacture
View Patent ↗A cannula assembly having a retention member and a method of manufacture of the cannula assembly is provided. The cannula assembly includes a cannula and a sleeve disposed around the cannula from a proximal end to a distal end. The sleeve can include a balloon formed by a stretch blow molding process following local heating once advanced over the cannula. Once formed, the balloon can be conditioned to constrict against the cannula. A conditioning aid can be advanced over the balloon when it is still formable to constrict the balloon against the cannula.
1. A cannula assembly comprising:
a cannula having a proximal end, a distal end opposite the proximal end, and a lumen extending from the proximal end to the distal end along a longitudinal axis, the lumen configured to receive a surgical instrument therein, the cannula comprising:
a generally tubular cannula body having an exterior surface; and
a recess formed in the exterior surface of the cannula body adjacent the distal end of the cannula; and
a sleeve having a proximal end and a distal end, the sleeve disposed around the cannula from adjacent the proximal end of the cannula to the recess, the sleeve comprising:
an elongate tubular body;
a balloon positioned distal the elongate tubular body; and
a bonding segment distal the balloon, the bonding segment extending into the recess and coupled to the cannula, the bonding segment having a chamfered leading edge.
2. The cannula assembly of claim 1 , wherein the bonding segment defines a longitudinal axis, and wherein the chamfered leading edge defines an angle of between approximately 50 degrees and approximately 65 degrees relative to the longitudinal axis of the bonding segment.
3. The cannula assembly of claim 1 , further comprising an adhesive substantially within the recess to couple the distal end of the sleeve to the recess.
4. The cannula assembly of claim 1 , further comprising a hollow tubular member removably positioned on the distal end of the cannula around the balloon.
5. The cannula assembly of claim 4 , wherein the hollow tubular member comprises a smooth inner surface.
6. The cannula assembly of claim 5 , wherein the hollow tubular member has an inner diameter sized to compress the balloon against the cannula body.
7. The cannula assembly of claim 4 , wherein in an initial configuration with the hollow tubular member surrounding the balloon, the balloon is in a folded configuration.
8. The cannula assembly of claim 7 , wherein the folded configuration comprises an initial distal fold and a proximal fold.
9. The cannula assembly of claim 1 , wherein the sleeve is monolithically unitarily formed.
10. The cannula assembly of claim 9 , wherein the sleeve comprises a polyolefin material.