New ultrasound-guided L5 selective nerve root block puncture approach for the treatment of pain due to high-iliac-crest lumbar disc herniation: A case report.

Rationale: Lumbar 5 (L5) selective nerve root block is a common treatment for lumbar 4/5 disc herniation. It is difficult to perform real-time ultrasound-guided targeted L5 nerve root block because of the deep structure of the L5/S1 intervertebral foramen and the occlusion of the sacrum and ilium. Therefore, the safe and efficient implementation of L5 nerve root block is very important for improving the clinical promotion and use of this procedure.

Patient Concerns: A 43-year-old male, who presented with a 1-month history of lumbosacral and left lower limb pain.

Diagnoses: The characteristic manifestation of pain symptoms was continuous and distending-like pain, accompanied by numbness on the posterior side of the left lower limb. The pain could be exacerbated by prolonged standing, sedentary behavior, and turning over while being relieved by lying down to rest. The visual analog score was 7 triggered by innocuous stimuli, configuring a clinical picture of typical protrusion of the lumbar intervertebral disc. Physical examination: muscle tenderness, straight leg-raising test of the left lower limb was 60° (+), test of supinating and throwing out one's belly (+), and Achilles tendon reflex (-).

Interventions: The patient underwent an ultrasound-guided L5 nerve root block with a modified puncture approach technique called the "transverse process-zygapophysis separation method."

Outcomes: The patient had a successful nerve blockade characterized by significant reduction in pain after the operation.

Lesson: The innovative puncture approach method may be considered a therapeutic option in patients with chronic pain.