Embolic coil detachment mechanism with flexible distal member, resistive electrical heating element and shape memory polymer element

A detachment system for delivering embolic coils to a treatment site in a vasculature of a patient, comprising:

• an elongated, flexible shape memory polymer elongated, flexible shape memory polymer tube having a distal portion and a proximal portion, said elongated, flexible shape memory polymer tube having a tubular wall with an inner wall surface defining an interior lumen extending through the elongated, flexible shape memory polymer tube between the distal portion and the proximal portion of the elongated, flexible shape memory polymer tube, the distal portion of the elongated, flexible shape memory polymer tube having a temporary shape having a first configuration with a first inner diameter and a permanent shape having a second configuration with a second inner diameter that is larger than said first inner diameter of said first configuration of said temporary shape;
• a headpiece having a distal portion and a proximal portion, said proximal portion of said headpiece being releasably mounted within said distal portion of said elongated, flexible shape memory polymer tube, said second inner diameter of said second configuration of said permanent shape of said elongated, flexible shape memory polymer tube being larger than an outer diameter of said headpiece;
• a therapeutic embolic coil having a distal end and a proximal end, said proximal end of said therapeutic embolic coil being fixedly attached to the distal portion of said headpiece, said proximal portion of the headpiece extending proximally of said proximal portion of the embolic coil;
• and
• a resistive heating element contained within the interior lumen of the distal portion of the flexible shape memory polymer tube, and disposed longitudinally along and in immediate contact with the inner wall surface of the tubular wall of the distal portion of the flexible shape memory polymer tube between the inner wall surface of said tubular wall of said elongated, flexible shape memory polymer tube and said proximal portion of said headpiece, said resistive heating element being configured to provide direct, even heating of at least a substantial majority of the length of the distal portion of the flexible shape memory polymer tube when the resistive heating element is energized, whereby said headpiece and said therapeutic embolic coil attached thereto are configured to be releasable from said distal portion of said elongated, flexible shape memory polymer tube by heating of said distal portion of the elongated, flexible shape memory polymer tube by said resistive heating element to cause said distal portion of the elongated, flexible shape memory polymer tube to change from said temporary shape having a reduced diameter configuration to said enlarged diameter configuration.