Rectus sheath block
Introduction: The rectus sheath block or (para) umbilical block has enjoyed a resurgence in popularity over the past decade. 1-3 Rectus sheath block can be effectively used for postoperative analgesia for all midline abdominal procedures, but is most commonly used for umbilical hernia repair and laparoscopy. It is commonly performed with ultrasound guidance as the rectus muscles are easily recognized. Two recent prospective case series using US needle guidance for rectus sheath block for pediatric umbilical surgery had a high success rate without opioid supplementation. 4,5 The rectus sheath block technique has not featured as commonly in the adult literature, however, it can be just as easily performed in this patient group.
Skill level: Simple.
Procedure time: 2-4 mins (1 mins for experienced practitioners)
Common: postoperative analgesia for:
1. Umbilical hernia repair
2. Laparoscopy (umbilical port)
Less common: Midline incision laparotomy.
Sedation: e.g. midazolam 2 mg +alfentanil 250-500 mcg or more commonly after GA.
Anatomy: The umbilicus is supplied bilaterally by the terminal cutaneous branch of the T10 spinal (intercostal) nerves, which provide sensory innervation to the skin after passing through the rectus abdominis muscles. The rectus sheath (fascia of the external/internal oblique aponeurosis) envelops the two muscles. In so doing they provide a compartment for the injection of local anesthetic. Injection of local anesthetic between the rectus muscle and the posterior rectus sheath facilitates anesthetic spread in a caudad and cephalad direction. It also minimises the theoretical concern of local anesthetic myotoxicity if local anesthetic is injected directly into the rectus muscle.
Surface landmarks: mark out the rectus abdominis muscle.
Needle: 22G blunt needle.
1. High resolution liner probe e.g. SonoSite L38.
2. 22G blunt needle.
3. 20 mL LA filled syringe
Procedure (Video 1)
1. Place probe 2-5 cm lateral to the midline and identify the rectus muscle, which is generally 1-4 cm deep (Figs. 1 and 2).
Fig. 1. Rectus sheath block (pediatric). With out-of-plane probe-needle orientation, a blunt needle facilitates correct LA placement as needle contact with the fascial layers is readily appreciated.
Fig. 2. Rectus sheath block ultrasound image. RM=rectus muscle.
2. Advance the short bevel needle using out-of-plane needle-probe alignment with multiple short/sharp movements while simultaneously observing for tissue displacement within the rectus muscle. One or more test injections of LA are performed until separation of the muscle and posterior rectus sheath is observed (Fig. 3). 6
Fig. 3. Rectus sheath block ultrasound image. Appropriate separation of rectus muscle (RM) and posterior rectus sheath (PS) on correct LA placement.
3. Inject the full LA dose.
4. Repeat block on the opposite side
Local anesthetic regimen: 10 mL ropivacaine 0.5-75% each side (paediatric dose: 0.1 mL/kg each side)
1. Bowel perforation. Exceedingly inlikely when the needle tip is maintained superficial.
Video 1. Rectus sheath block (sonography) - paediatric
1. Courreges P, Poddevin F. Rectus sheath block in infants: what suitability? Paediatr Anaesth 1998;8:181-2.
2. Courreges P, Poddevin F, Lecoutre D. Para-umbilical block: a new concept for regional anaesthesia in children. Paediatr Anaesth 1997;7:211-4.
3. Ferguson S, Thomas V, Lewis I. The rectus sheath block in paediatric anaesthesia: new indications for an old technique? Paediatr Anaesth 1996;6:463-6.
4. de Jose Maria B, Gotzens V, Mabrok M. Ultrasound-guided umbilical nerve block in children: a brief description of a new approach. Paediatr Anaesth 2007;17:44-50.
5. Willschke H, Bosenberg A, Marhofer P, et al. Ultrasonography-guided rectus sheath block in paediatric anaesthesia--a new approach to an old technique. Br J Anaesth 2006;97:244-9.
6. Chowdary. Ultrasound Study to Determine the Accuracy of Needle Placement for Rectus Sheath Block by Conventional Method in children. www.asra.com/abstracts 2005;A51.