Oblique plane anterior quadratus lumborum block in a pediatric patient

Dear Editor, Quadratus lumborum (QL) block is a posterior abdominal wall block that has been commonly used to provide perioperative analgesia in abdomino-pelvic surgeries.[1] In anterior QL block, the patient is placed in the lateral decubitus position, and the ultrasound probe is kept transversely in an anteroposterior direction in the midaxillary line between the iliac crest and the costal margin. The needle is inserted in a posterior-to-anterior direction after identification of transverse process and vertebral body to deposit the local anesthetic (LA) between the QL and psoas major (PM) muscles.[2] However, this approach to needle insertion has certain limitations, like transverse process in the needle path resulting in needle manipulation, steeper needle probe angle resulting in poor needle visibility, and inability to see vertical drug spread at the time of LA injection.[3] Some studies have described the novel approach to anterior QL block, which is the oblique sagittal anterior QL block.[4,5] In this block, LA can spread posteriorly as far as possible to block nerves supplying the hip joint area. They have proposed two possible mechanisms: one is due to direct blockade of nerves (iliohypogastric nerve, ilioinguinal nerve, lateral femoral cutaneous nerve, subcostal nerve, and genital femoral nerve) running between the quadratus lumbar muscle and the PM muscle; and the other is due to diffusion of LA into the paravertebral space and the blockade of spinal nerves (T7-L2).[2] Here, we are going to describe the use of this approach of QL block in a pediatric patient. One-year child (11 kg) was scheduled for right-sided open orchidopexy. After general anesthesia and supraglottic device placement, the patient was positioned laterally with the operating side upward. In this oblique plane QL block, the ultrasound probe was rotated longitudinally around 45 degree clockwise, from its initial anteroposterior transverse position [Figure 1, Panel A]. After identification of latissimus dorsi, QL, erector spinae, and PM muscle [Figure 1, Panel B], an echogenic needle (22G, 8 cm, B. Braun, Germany) was inserted in-plane to probe in caudocranial direction to keep the needle tip between QL and PM muscle. After negative aspiration for blood, injection of ropivacaine 0.2% of volume 6 mL was injected between QL and PM muscle for anterior QL block [Figure 1, Panel C]. The spread of LA between QL and PM muscle was also seen after placing the probe transversely in anteroposterior orientation in the midaxillary line [Figure 1, Panel D]. Written and informed consent for publication was taken from the parents. The surgery was completed uneventfully. There was no requirement for any top-up fentanyl during the intraoperative period. In the postoperative period, the patient received 15 mg/kg IV paracetamol every sixth hour. The patient was assessed at 1, 6, and 24 h postoperatively, with the Children’s Hospital of Eastern Ontario Pain Scale being 5/13, 4/13, and 4/13 at rest.Figure 1: Oblique plane approach to quadratus lumborum (QL) block; Panel A: needle probe position, Panel B: sonoanatomy, Panel C: injected drug spread between psoas major and QL muscle, Panel D: confirmation of injected drug spread in the transverse probe position. The white arrows show the needle trajectory. EO = external oblique, IO = internal oblique, TA = transversus abdominisAs per our experience, this approach was easier to perform with better needle visualization than the conventional transverse approach in the pediatric age group. Comparative studies are required to validate our findings. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.