Water Vapor Therapy
Combining the Efficiency of Convective Thermal Energy and Anatomy
A hand-held delivery device, similar in shape and size to a cystoscope, is connected to a generator. A few drops of sterile water are heated to approximately 103oC and as the sterile water is transformed from liquid into steam, or vapor, the volume expands by almost 1,700 times and stores 540 calories of thermal energy for every milliliter (mL).
A precise dose of water vapor thermal energy is delivered into the targeted tissue using a small needle with multiple emitter holes to enable controlled and uniform vapor dispersion. The vapor is delivered into the targeted tissue at slightly above interstitial pressure, convectively driving the water vapor through tissue interstices, where it condenses and transfers the stored thermal energy directly to the targeted tissue. This convective heat transfer is what differentiates Rezūm from other ablative thermal therapies that rely on the slower, less precise and less efficient process of conduction to heat tissue.
Convective transfer of water vapor thermal energy to tissue is fast but also self-limiting. Water vapor condenses back into its liquid state as it is dispersed through tissue, so the energy travels no further than its intended area of treatment. The prostate is comprised of three separate zones or regions and the enlarged tissue that causes BPH is located in two of them – the transition zone and the central zone. The tissue separating these zones provides a natural anatomical barrier that contains the vapor within the intended treatment areas.