In the world, the method of analgesia by continuous infusion of anesthetic agent into the incision through a small size multi line catheter is applied on many types of surgery such as spine surgery [33], joint surgery, inguinal bump drainage surgery, mastectomy and abdominal and thoracic surgery [33] [53] [73] In Vietnam, there have not been any researches using multi - hole catheters to relieve pain after abdominal surgery.