Superelastic medical instrument

A biopsy needle assembly, comprising:

• a needle formed from a superelastic alloy, the needle including:
• a body portion extending from a distal end of the needle to a proximal end of the needle, and
• an inner surface of the needle forming a lumen extending through at least a portion of the body portion to an opening in the distal end, wherein the lumen and the opening are configured to acquire a tissue biopsy;
• an elongate member attached at the proximal end of the needle;
• and
• a tubular jacket including an interior channel, wherein:
• in a first configuration, the distal end of the needle is positioned within the interior channel, and
• in a second configuration, in response to distal movement of the elongate member through the interior channel, the distal end of the needle is extended beyond a distal end of the tubular jacket;
• wherein the elongate member comprises a polymer tube reflowed around an overlap region located at the proximal end of the needle;
• and
• wherein the needle further comprises a plurality of surface features formed on the needle at the overlap region, wherein the polymer tube is reflowed around the surface features.