Description

A major proportion of pain experienced by patients undergoing abdominal surgeries is due to somatic pain signals derived from the abdominal wall. The central portion of anterior abdominal wall components (skin, muscles and parietal peritoneum) is innervated by sensory neurons branching from the anterior rami of spinal nerves T7 to T1. These neurons lie between the rectus abdominis muscle and posterior rectus sheath, and pierce the rectus muscle close to the midline. The tendinous intersections of the rectus muscle do not fuse with the posterior rectus sheath, thereby allowing the injectate to spread cephalo-caudally within this potential space. Rectus sheath (RS) block has been described for any midline abdominal incisions (epigastric and umbilical hernia repairs). As visceral pain becomes attenuated by the 2nd postoperative day, rectus sheath block can also be administered for midline laparotomy.

However, the effects of rectus sheath block analgesia on the respiratory function after abdominal surgery with midline incisions are still under investigation.