Analgesia, Postoperative

• Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology. 1095 Jiefang Avenue, Wuhan City, Hubei Province — Wuhan, Hubei, China
• Tongji Hospital — Wuhan, Hubei, China

• Department of Anesthesiology; Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg Eppendorf — Hamburg, Germany

• University hospital of Split — Split, Croatia

• faculty of human medicine, Zagazig university hospitals — El Sharkia, Egypt

• faculty of human medicine, Zagazig university hospitals — El Sharkia, Egypt
• Faculty of Human Medicine, Zagazig University — El Sharkia, Egypt

• Faculty of Medicine — Cairo, Egypt

• Shenzhen Children's Hospital — Shenzhen, Guangdong, China

Not specified

• Bangladesh Medical University — Dhaka, Bangladesh

• Faculity of medicine, Zagazig university, Zagazig — Zagazig, Egypt