A sterile non-bioabsorbable expandable device designed for long-term placement in the vagina to provide support and/or to prevent shrinking. It is especially used in the treatment of vaginal agenesis involving surgical intervention (e.g., to hold a skin graft postoperatively) or without surgical intervention, for the prevention of vaginal contracture or stenosis after radiotherapy, or for vaginal dilation following transgender vaginoplasty. It is available in many different configurations, sizes, and materials (e.g., an inflatable tubular silicone-elastomer envelope with valves and internal drains) and may be inserted and expanded with a balloon catheter or dilator.