The principle of a gastric sleeve is to restrict how much you are eating by creating a long narrow sleeve of stomach. Stretching it with a balloon would not help weight loss. Bands can be placed to surround the stomach pouch of a gastric bypass to enhance the mechanical restriction, however the same effect has not be theorized to help weight loss with a sleeve gastrectomy. Sleeve gastrectomies can be converted to a mini-bypass or full bypass if weight loss has plateaued. It is best to discuss all these options with the team providing treatment.