Weight loss in sleeve surgery: It is expected that with sleeve surgery, a person will lose between 70 and 90 percent of their excess weight in 18 months or an average of 45 kg in 18 months.  
Disadvantages : Some of the complications of sleeve surgery are similar to many other surgeries, such as wound infection, suture sensitivity, and… that these complications may occur in any other operation that is not necessarily related to the gastrointestinal tract or obesity. However, these cases are less likely to occur due to the laparoscopic method and the small size of the incisions, and in case of occurrence, the severity of the complication will be milder. Other complications, such as embolism, bleeding, and leakage or leakage from the surgical site, are somewhat preventable and not specific to the sleeve, and largely depend on preoperative counseling and the patient's condition and mobility.  
Among other factors that affect the incidence of bleeding and leakage after sleeve : 
 1- The material of the staples and their brand  
2- Standard surgical technique by an experienced and academically educated surgeon (laparoscopic fellowship and obesity surgery) Although these subspecialty surgeries may be performed by non-specialists, but the attention to detail and the ability to control the operation in the event of unintended events is beyond the power of these physicians and increases the error rate and risks and complications and even death.  
3- Tissue repair of the patient's body: which tries to reach the ideal level before the operation with comprehensive preoperative examinations.       
Sleeve surgery and cancer prevention On Contrary to some people's beliefs about the connection between sleeve surgery and cancer, it must be acknowledged that this theory is completely wrong and that sleeve surgery does not itself cause or develop gastric cancer unless the person has gastric cancer or a predisposing factor before sleeve surgery or had another agent which remained undiagnosed after surgery and continued to progress. In addition, Sleeve helps prevent many cancers, including ovarian cancer, due to significant weight loss.  
Gastric enlargement after surgery After sleeve surgery, over time, if you do not follow the nutritional tips, there is a possibility of 10 to 15% increase in stomach volume, which is very small due to the 80% reduction in volume during the operation.