Aim: The impact of extended antral resection (AR) after laparoscopic sleeve gastrectomy (LSG) on weight loss changes and metabolic response is still not clearly elucidated with conflicting results. The investigator's retrospective cohort study aimed to determine whether AR is superior to antral preservation (AP) regarding weight loss and resolution of co-morbidities.

Methods: Patients were divided into two groups according to the distance of gastric division as AR group (2cm from pylorus) and AP group (6cm from pylorus). Postoperative excess weight loss percentile (%EWL) and total body weight loss percentiles (%TBWL) at the end of first, 6th and 12 months were compared. Secondly, metabolic parameters and complications were compared.

Following approval of the ethical committee patients who underwent LSG between January 2016 and June 2018 are retrospectively analyzed. Patients with BMI > 40 were included. Patients with a history of previous bariatric surgery and patients who did not attend regular follow-up visits (first, 6th and 12 months) are excluded.

The patients were grouped according to the distance of gastric division as AP group (6cm from pylorus) and AR group (2cm prom pylorus). The first 68 patients underwent AP, and the following 43 patients underwent AR.

Patient characteristics and demographic data, including age, gender, BMI, co-morbid diseases (hypertension (HT), Type II diabetes, dyslipidemia), biochemical parameters (glucose, HbA1c, C-peptide, insulin, , cholesterol, triglyceride, HDL, LDL, and VLDL was extracted from a prospectively prepared patient's chart. The 30-day outcomes including postoperative morbidity and mortality are taken from patient's folder.

Weight loss alteration at the end of first, 6th and 12 months are calculated as %EWL and %TBWL. The %EWL is calculated as [(preoperative weight - follow up weight) / (preoperative weight-ideal weight)] x100, with ideal weight based on a BMI of 25kg/m2. The total body weight loss percentile (%TBWL) is calculated as [(preoperative weight - follow up weight) / (preoperative body weight)] x100.

Resolution of co-morbidities was defined as reduction of co-morbidity related symptom and signs with change of specific biochemical blood tests to normal ranges.

The Clavien-Dindo classification scale was used to define the severity of complications: Grade I; no requirement of specific intervention, Grade II; antibiotic treatment, total parenteral nutrition, and/or blood transfusion is mandatory, Grade III; invasive interventions such as endoscopy, percutaneous drainage, or surgery is needed, Grade IV; intensive care management for organ dysfunction, and Grade V; as death, respectively [10].

2.1. Surgical Technique The LSGs were performed by two surgeons. Patients were placed in supine position. Antibiotic prophylaxis was started before anesthesia induction by using 2g first-generation cephalosporin for patients <120kg, and 3g for patients ≥120 kg. The liver is retracted by using Nathanson Hook. The greater omentum is carefully dissected from the stomach at a distance of 2cm for the patients with AR, and 6cm for patients with AP. The omental dissection was performed using 5mm-abdominal ligature (Ligasure®, Metronic-Covidien, Minneapolis, USA), from the antrum towards the angle of His. Transection from the omentum is continued until the left crus has been identified. All sleeves are transected using 36 French orogastric tubes. Green cartridges (4.8 mm staple height) are used for the first firing and blue cartridges (3.5 mm) for the rest. Neither oversewing sutures to the staple line nor staple line reinforcement products are used. Homeostatic metallic clips are used for bleeding at the staple line. If bleeding persists and cannot be controlled, an interrupted suture is performed at the point of bleeding. A leak test with methylene blue is performed to the gastric remnant to assess the integrity of the suture line. The gastric specimen is removed through the 12mm trocar. The procedure is completed by placing an abdominal drain just next to the staple line.

Inclusion Criteria:

• Patients with Body Mass Index > 40 were included

Exclusion Criteria:

• Patients with a history of previous bariatric surgery and patients who did not attend regular follow-up visits (first, 6th and 12 months) are excluded

Patients who underwent Laparoscopic Sleeve Gastrectomy between January 2016 and June 2018 are retrospectively analyzed.