BLOCK AT A GLANCE
Fascial plane injection of local anesthetic (LA) between the rectus abdominis muscle and its posterior sheath.
Indications: Postoperative analgesia for midline abdominal incisions (e.g., umbilical hernia repair, periumbilical surgeries)
Goal: Spread of the LA along the fascial plane to block the anterior cutaneous branches of the intercostal nerves
Local anesthetic volume: 10 to 15 mL
The rectus sheath block provides somatic analgesia at the abdominal midline, therefore it is indicated in abdominal surgery involving a midline laparotomy. The block is commonly used in the pediatric population for umbilical hernia repair. In adults, it is also used for single-incision cholecystectomy and some gynecologic procedures. Ultrasound (US) guidance allows for greater reliability in administering LA in the correct plane, making this block more reproducible, and decreasing the risk for potential for complications. Continuous rectus sheath blocks have also been also described in patients after laparotomy. Among the reported advantages are reduced opioid requirements, earlier mobilization, and avoidance of complications related to neuraxial techniques.
The duration, extent, and quality of analgesia with a rectus sheath block can vary. As with other fascial plane techniques, efficacy depends on the spread of the LA, and therefore, the volume of LA that reaches the targeted nerves. Although ultrasound may reduce the risk of complications, peritoneal and bowel puncture can occur if the needle depth and path are not controlled. Puncture of the epigastric vessels that may be in the path of the needle can lead to hematoma formation in the rectus sheath.
The rectus abdominis muscles are vertically paired, oval-shaped muscles on the anterior abdominal wall. They are connected together in the midline by the linea alba. They originate from the pubic symphysis and pubic crest and insert in the xiphoid process and costal cartilages of ribs 7 to 10. The rectus abdominis muscle is enclosed by the rectus sheath, which is formed by the aponeurosis of the three laterally located muscles: the external oblique, internal oblique, and transversus abdominis. The anterior layer of the rectus sheath is complete in its entirety, while the posterior layer is absent at the lower quarter of the rectus abdominis muscle (Figure 39-1). This is known as the arcuate line, which defines the point where the posterior aponeurosis of the internal oblique and the transversus abdominis muscles become part of the anterior rectus sheath, leaving only the transversalis fascia to cover the rectus abdominis muscle posteriorly. This arcuate line is found one-third of the distance from the umbilicus to the pubic crest.
Anatomy and innervation of the abdominal wall.
The abdominal wall is innervated by the thoracoabdominal nerves (T6-T12) and the ilioinguinal/iliohypogastric nerves (L1). After giving off the perforating lateral cutaneous branches, the intercostal nerves ...