The invention relates to medical devices and, particularly, catheter medical devices. In an aspect is a nerve block catheter system comprising a dual-sheath catheter comprising an inner sheath and an outer sheath, wherein distal ends of the sheaths are connected, the inner sheath defines a fluid delivery lumen, and the outer sheath comprises a tissue lock movable between a collapsed position and an extended position, wherein the tissue lock forms a reversible tissue anchor when in the extended position, and an actuator connected to the proximate end of the catheter and configured to activate the tissue lock by sliding the outer sheath length-wise relative to the inner sheath.
