A ureteral stent includes an elongated member, which has a tubular shape, and a distal retention structure. The elongated member includes a sidewall that defines a lumen and has a spiral-shaped opening with at least two rotations. The sidewall has an inner surface and an outer surface. The sidewall between the inner surface and the outer surface is devoid of another lumen. The elongated member is configured to move between a retracted configuration and an expanded configuration along a longitudinal axis of the lumen. The distal retention structure is disposed at a distal end of the elongated member for retention in a kidney. The distal retention structure defines a lumen in fluid communication with the lumen defined by the sidewall of the elongated member.