Rectus Sheath or Umbilical Block
The rectus sheath or para-umbilical block[272]
[273]
can provide intraoperative and postoperative
analgesia in patients undergoing umbilical, epigastric, or linea alba hernia repairs.
The peri-umbilical area receives its sensory supply from the 10th right and left
intercostal nerves after they have pierced and penetrated the posterior fascia of
the aponeuroses of the rectus abdominis muscles. The child is placed supine. The
landmarks are the umbilicus and the lateral border of the right and left rectus abdominis
muscles. In chubby infants, this lateral border is not easily found, and a line
drawn 2 to 3 cm lateral to the linea alba on each side can be used instead.
One site of puncture per side is marked on this lateral line at
the level of the umbilicus ( Fig. 45-22
).
The technique consists of inserting obliquely a short and short-beveled needle through
the skin in the direction of the upper border of the umbilicus at a 60-degree angle
to the skin until it pierces (with some difficulty) the rectus sheath with a characteristic
and often audible crack. A volume of 0.2 mL/kg per side of long-lasting local anesthetic
(0.5% bupivacaine or 0.5% to 0.75% ropivacaine) is then injected in a fan-shape manner
at the upper, lateral, and lower border of the umbilicus. An additional subcutaneous
injection on withdrawal of the needle is recommended to improve the quality of analgesia.
[273]
The same technique is repeated on the other
side. Addition of 1 µg/kg of clonidine improves the quality of blockade and
provides some sedation for 1 to 2 hours, which allows
Figure 45-22
Umbilical or rectus sheath block, identifying the sites
of the umbilicus (1) and lateral border of the left rectus muscle (2).
quiet emergence from anesthesia at the end of the surgery. The failure rate is virtually
zero, as is the complication rate, provided no sharp needle is used and introduced
perpendicular to the abdominal wall (which can result in intraperitoneal penetration
of needle). When the technique is first introduced in clinical practice, the surgeons
may complain of "edema" at the skin incision, but after they are used to the procedure,
they usually consider this effect to be advantageous because identification and dissection
of the fascial planes is made easier.
