Patent ID: 8287503

Claim:
A cannula assembly, comprising: a cannula including a substantially longitudinal tube having a proximal end, a distal end, a lumen extending between the proximal end and the distal end, a proximal portion having a first, larger periphery, a distal portion having a second, smaller periphery, an annular groove on the outer surface of the distal portion of the cannula toward the distal end of the cannula, and a plurality of channels on the outer surface of the distal portion of the cannula, the plurality of channels extending along the length of the cannula from substantially a proximal end of the distal portion of the cannula distally to a point proximal to the annular groove near the distal end of the cannula; a sleeve including a substantially longitudinal tube having a proximal end, a distal end, a lumen extending between the proximal end and the distal end, a proximal portion having a first, larger periphery, a distal portion having a second, smaller periphery, and an annular groove on the outer surface of the distal portion of the sleeve toward the distal end of the sleeve, the lumen of the sleeve being configured to accept the cannula; a balloon including a tubular sleeve, the balloon being coupled to the annular groove on the outer surface of the distal portion of the sleeve, extending distally from the distal end of the sleeve to the annular groove on the outer surface of the distal portion of the cannula, and being coupled to the annular groove of the cannula; grease, the grease coating an inner surface of the balloon; and a seal positioned between the cannula and the sleeve and compressed sufficiently to form a seal between the cannula and the sleeve, wherein the sleeve being coupled to the cannula and positioned over the cannula with the proximal portion of the sleeve fitting over at least a distal region of the proximal portion of the cannula and the distal portion of the sleeve fitting over at least a portion of the distal portion of the cannula, the distal end of the sleeve being positioned proximal to the distal ends of the plurality of channels on the outer surface of the cannula, and the space between the outer surface of the cannula with the plurality of channels, the inner surface of the sleeve, the seal, and the balloon forming a substantially closed chamber.