The most common complication associated with adjustable gastric banding is the enlargement of the stomach pouch, which can occur if the stomach slips up through the band. However, modifications to the technique have been made to prevent this from occurring. There have also been cases where the band erodes into the stomach.
In the case of a sleeve gastrectomy, as this is a significant surgical procedure, there are all the normal risks associated with abdominal surgery such as bleeding, pain, and blood clots. In a very few cases there may be some leakage from the stomach through the staple line where the stomach has been divided, however in most cases this can be detected quickly and repaired laparoscopically.