Rectus sheath catheters for continuous analgesia after upper abdominal surgery.

The segmental nerves T6-T11 pass through and innervate the rectus abdominis muscle and overlying skin. The arcuate lines compartmentalize the rectus, but they are deficient posteriorly and hence a catheter tunnelled into the posterior sheath can be used to achieve an effective continuous analgesic block. Volume is important to fill the compartment. It is a simple surgical procedure that has several advantages and appears a viable alternative to epidural analgesia.