Ultrasound-guided lumbar plexus block in children and adolescents using a transverse lumbar paravertebral sonogram: Initial experience

Abstract

Background: The clinical reliability and reproducibility of ultrasound-guided lumbar plexus blocks is not established in pediatric populations. We present the results of a combined nerve stimulation ultrasound-guided lumbar plexus block using the vertebral body, transverse process, and psoas muscle as landmarks on a transverse lumbar paravertebral sonogram with mid-axillary transducer placement, "shamrock method," in children and adolescents.

Aims: Our primary objective was to determine the rate of achieving sensory changes in the lumbar plexus distribution. Secondary outcomes were performance time, reliability of echo-landmarks, measures of patient comfort, and complications.

Methods: We reviewed prospectively collected quality assurance data and electronic medical records of 21 patients having major orthopedic surgery with lumbar plexus block catheter for postoperative analgesia.

Results: Twenty-one patients were studied with mean age and weight (SD, range) of 13.6 years (3.8, 6-18) and 49.3 kg (18.6, 19.2-87.6). Surgical procedures included periacetabular osteotomy, pelvic osteotomy, and proximal femoral osteotomy. Mean volume of 0.5 mL/kg (0.05) 0.2% ropivacaine produced thermal sensory changes to femoral and lateral femoral cutaneous nerves in 20/21 (95% CI 0.76 to >0.99) and 19/21 (95% CI 0.70-0.99) patients. Identification of transverse process (TP), vertebral body (VB), and psoas muscle (PM): 21/21 (95% CI 0.86-1.0). Average block performance time was 9:08 minutes (2:09, 2-13). Average opioid consumption (SD) in operating room, postanesthesia care unit, 0-12 and 12-24-hour periods were 0.17 mg/kg (0.08), 0.08 mg/kg (0.06), 0.06 mg/kg (0.06), and 0.06 mg/kg (0.05). Median pain score by severity category in postanesthesia care unit: (0-3) 66.7%, (4-6) 28.5%, (>7) 4.8%; 0-12 hours: (0-3) 76.2%, (4-6) 19.0%, (>7) 4.8%; 12-24 hours: (0-3) 57.2%, (4-6) 42.8%, (>7) 0%. No complications were recorded.

Conclusion: Ultrasound guidance using lateral imaging of transverse process, vertebral body, and psoas muscle allows practitioners to reach the nerves of the lumbar plexus and achieve sensory block in pediatric patients with a high success rate.

Keywords: acute pain; child; local anesthetics; orthopedics; regional ultrasound.