I read with interest the article “Lumbar Plexus in Children” by Lukas Kirchmair et al.  1published in the August 2004 issue of Anesthesiology. The authors have nicely shown that sonography of the lumbar plexus in children is feasible, they have clarified the anatomical understanding, and they have given additional information on the depth of the lumbar plexus in pediatric patients.

In addition, they applied their technique to five children scheduled to undergo inguinal hernia repair and concluded that all lumbar plexus blocks provided effective anesthesia and analgesia of the inguinal region during surgery and for postoperative pain relief. Although I am unable to check the clinical effects in these five individual patients, I have considerable doubt that lumbar plexus block is a suitable anesthetic technique for inguinal hernia repair and would not recommend it for the following reasons:

First, the iliohypogastric nerve arises from the roots T12 and L1, and the ilioinguinal nerve arises from L1. These two nerves are usually not densely blocked by injections made at an L4–L5 level. Even the genitofemoral nerve, arising from L1 and L2, is often missed.

Second, a successful lumbar plexus block is followed by a profound motor blockade of all knee extensor and most hip adductor muscles. This is clearly an undesirable side effect after inguinal hernia repair. Avoiding this by using a small volume and a low concentration of the local anesthetic does not seem to be a valuable strategy, especially when nerves far away from the injection site must be blocked.

Third, clinically, in awake adolescents, using the posterior lumbar plexus block with an injection at the L4–L5 level in combination with a sciatic nerve block, incisions coming high up, close to the inguinal ligament, are often troublesome. The ilioinguinal and genitofemoral nerves are often not sufficiently blocked.

In summary, lumbar plexus block can be used in children. However, its use should be restricted to indications where this technique is clearly effective, e.g. , for lower limb procedures involving parts of the hip or extensive knee surgery, and where no other less invasive alternative exists.

Kantonsspital, Luzern, Switzerland. joehrmartin@bluewin.ch

Kirchmair L, Enna B, Mitterschiffthaler G, Moriggl B, Greher M, Marhofer P, Kapral S, Gassner I: Lumbar plexus in children: A sonographic study and its relevance to pediatric regional anesthesia. Anesthesiology 2004; 101:445–50