Ultrasound-Guided Rectus Sheath Block in a Pediatric Patient

CHAPTER 1

The anterior cutaneous branch of the anterior ramus of the spinal nerve from T6 to L1 transverses the plane between the internal oblique and transverse abdominis muscles before continuing between the rectus abdominis muscle, and the posterior layer of the rectus sheath. It then pierces the rectus abdominis muscle to provide sensory innervation to the anterior abdominal wall. The rectus sheath block, RSB, involves depositing local anesthetic between the dorsal aspect of the rectus abdominis muscle and the posterior rectus sheath to block the anterior cutaneous branch of the spinal nerve as it crosses through this region. This technique is effective for midline abdominal incisions, providing analgesia from the upper to the lower abdomen, depending on the level of injection. The trajectory of the anterior cutaneous branch varies among individuals. If local anesthetic is injected too medially, the nerve may already have penetrated the rectus abdominis muscle and assumed an anterior course resulting in suboptimal analgesia. Accordingly, administering the local anesthetic as laterally as possible relative to the rectus abdominis muscle is preferable.

CHAPTER 2

Now, we will present the real-time video of the procedure. The patient is a male neonate weighing 3.9 kilogram who is scheduled to undergo pyloromyotomy for hypertrophic pyloric stenosis.

CHAPTER 3

Place the probe perpendicular to the body axis around the umbilicus to visualize the rectus abdominis muscle and posterior layer of the rectus sheath. Center the lateral edge of the rectus abdominis on the ultrasound screen. Using a 25-gauge regular bevel needle, perform an in-plane approach from the lateral side to puncture and enter the rectus abdominis muscle. Injection, please. Once inside the rectus abdominis muscle, carefully advance the needle until it overlaps the posterior layer of the rectus sheath, ensuring accurate visualization of the needle tip. If the echo-free space expand with administration of a small amount of local anesthetic, advance the needle further into this space while administering additional local anesthetics. Perform the same procedure on the opposite side.

CHAPTER 4

In pediatric population, RSB is particularly useful for umbilical hernia repair and laparoscopic procedures involving umbilical port placement. It is also effective for circumumbilical incision in neonates undergoing surgery for duodenal atresia, hypertrophic pyloric stenosis, intestinal malrotation, or ovarian cysts. RSB is included among the plan A blocks and is widely used in pediatric anesthesia, offering exceptional efficacy relative to its technical simplicity. In neonates, the pronounced tenting of the abdominal wall makes it advisable to use a regular bevel needle with a sharper tip rather than a short bevel needle. The recommended dosage is 0.2 milliliter per kilogram per site, ensuring that the maximum allowable dose is not exceeded.