**4.2 Leak**

Leak rates range from 0.5–7.0%, though most recent reported leak rate is about 1%, reflecting improvements with time and experience in the LSG technique [73, 75]. Gastric leak can result from mechanical forces that stress the staple line or ischemia. About 75–85% of LSG leaks occur at the proximal third of the greater curvature staple line, as opposed to the distal or antral staple line, and usually occur at postoperative day 5 or later [75]. Clinically, post-LSG leak presents with left upper quadrant pain, tachycardia, fever, or leukocytosis. Upper gastrointestinal contrast studies have low sensitivity (0–25%) but high specificity (90–95%) [72]. Due to its greater sensitivity, computerized tomography (CT) scan with oral and intravenous contrast is now used for diagnosis of a leak in clinically stable patients with suggestive signs or symptoms [72]. For acute postoperative leak, patients who are not stable enough for CT should be returned to the operating room for diagnostic laparoscopy. In acute leak, the objective is adequate drainage to prevent or mitigate abdominal sepsis. Treatment includes adequate drainage, nutritional support, and antibiotics. In most cases, resolution of the leak is a matter of time, sometimes taking several months [76]. Endoscopic treatments are increasingly utilized with variable success rates in an effort to avoid surgical interventions [77].
