The Effect of Postoperative Referred Pain in the Left Shoulder on Short-term Outcomes for Laparoscopic Gastrectomy

Inclusion Criteria: * Age from 18 to 75 years * Primary gastric adenocarcinoma (papillary, tubular, mucinous, signet ring cell, or poorly differentiated) confirmed pathologically by endoscopic biopsy * cT1-4a, N0-3, M0 at preoperative evaluation according to the American Joint Committee on Cancer (AJCC) Cancer Staging Manual Seventh Edition * No distant metastasis is observed. And the spleen, pancreas or other adjacent organs are not involved by the tumor. * Performance status of 0 or 1 on Eastern Cooperative Oncology Group scale (ECOG) * American Society of Anesthesiology score (ASA) class I, II, or III * Written informed consent Exclusion Criteria: * patients whose previous history of chronic shoulder pain * Women during pregnancy or breast-feeding * Severe mental disorder * History of previous upper abdominal surgery (except laparoscopic cholecystectomy) * History of previous gastrectomy, endoscopic mucosal resection or endoscopic submucosal dissection * Enlarged or bulky regional lymph node envelop important vessels * History of other malignant disease within past five years * History of previous neoadjuvant chemotherapy or radiotherapy * History of unstable angina or myocardial infarction within past six months * History of cerebrovascular accident within past six months * History of continuous systematic administration of corticosteroids within one month * Requirement of simultaneous surgery for other disease * Emergency surgery due to complication (bleeding, obstruction or perforation) caused by gastric cancer * FEV1\<50% of predicted values * Difficulty of understanding V A S(Visual Analogues Score).