The goal of this clinical trial is to learn if low pressure pneumoperitoneum and small incisions (low impact laparoscopy, LIL) works to reduce pain and improve pulmonary function in patients underwent to bariatric surgery. It will also learn about the safety and patients' satisfaction of the procedure. The main questions it aims to answer are: Does LIL lower post surgical pain and improve pulmonary function? Is LIL safe for obese patients? Researchers will compare LIL to standard laparoscopy performing sleeve gastrectomy in patients with obesity. Participants will: be randomised to LIL group or standard laparoscopy. After the operation the researchers will evaluate the pain and the efficiency of lung ventilation at pre-established intervals. after 3 months the patients will complete a questionnaire on aesthetic satisfaction and overall satisfaction.