The Effect and Safety of the Four Points Transversus Abdominis Plane Block

The anterior abdominal wall from below the xiphoid to infraumbilical area is dominated by the sensory nerves which originate from the anterior rami of the thoracolumbar spinal nerves from T6-L1. The branches nerves from T7-T12 are between aponeurosis internal oblique and transversus abdominal muscle. They can be approached with the ultrasound guidance at subcostal and lateral abdominal wall position. The bilateral transversus abdominis plane (TAP) block has been demonstrated effectiveness and safety in postoperative analgesia to the under abdominal surgery. However, the effect of one to the upper abdominal surgery is unclear. The four points TAP block has been described the first in 2010. The effect of the four points TAP block in postoperative analgesia to the upper abdominal surgery has been reported in recent years. Besides, the effect of thoracic paravertebral block (PVB) in postoperative analgesia to liver resection was also reported. The both techniques have been performing in some studies. The effect and safety of the both techniques have been reported. However, the evidence level is still weak. The investigators need to find a technique, which has effectiveness as well as safety to replace the epidural analgesia, which was confirmed that had many complications, in postoperative analgesia to the hepatectomy. The investigators hypothesized that the four points TAP block under the ultrasound guidance has more effectiveness than the thoracic paravertebral block in postoperative analgesia to the hepatectomy.