The sleeve operation in Tunisia is usually done under general anesthesia. The procedure lasts between 1h30 and 2h and requires 5 days of hospitalization.
The specifics of your surgery depend on your personal situation and the practices of your surgeon. Some sleeves are performed with large (open) incisions in the abdomen. But the most common practice is laparoscopy, which is performed by inserting small instruments through several small incisions in the upper abdomen.
The surgeon then creates a narrow sleeve (or tube) by stapling the stomach vertically and removing most of it (the part containing the cells that secrete ghrelin).