A dual lumen coaxial cannula assembly including a first infusion tube having a proximal end, a distal end, and a sidewall extending circumferentially therebetween, as well as a second drainage tube co-axially aligned with the first infusion tube, the second drainage tube having a proximal end, a distal end, and a sidewall extending circumferentially therebetween. The assembly also includes a connector assembly, which has an inlet portion through which a portion of the first infusion tube is configured to extend and an outlet portion through which a portion of the second drainage tube is configured to extend. The connector assembly is configured to enable selective axial displacement of the first infusion tube through the second drainage tube.