Floating spinal cannula and method of use

A method for delivering a therapeutic agent to a spinal cord target, said method comprising the steps of:

• providing a spinal cannula comprising a deployable cannula member having a distal end portion, a proximal end portion, a middle portion extending between the distal and proximal end portions, and a first lumen extending between the end portions, a fluid delivery line operably connected to the proximal end portion of the deployable cannula member and including a second lumen in fluid communication with the first lumen of the deployable cannula member, a support cannula proximally located from the deployable cannula member and securely connected to a portion of the fluid delivery line, and a delivery cannula having a distal end portion, a proximal end portion, and a third lumen extending between the end portions for receiving the support cannula, the proximal end portion including a locking mechanism for engaging the proximal end portion of the support cannula;
• engaging the locking mechanism of the delivery cannula with the proximal end portion of the support cannula so that the spinal cannula obtains a rigid configuration;
• implanting the distal end portion of the deployable cannula member at the spinal cord target;
• disengaging the locking mechanism of the delivery cannula to release the delivery cannula from the deployable cannula member;
• sliding the delivery cannula in a proximal direction over the support cannula so that the deployable cannula member is fluidly suspended at the spinal cord target;
• and
• infusing a therapeutic agent into the fluid delivery line so that the therapeutic agent is delivered to the spinal cord target.