Analgesic effects of erector spinae plane block can differ according to needle size: A case report

RATIONALE: Unlike brachial plexus block, erector spinae plane block (ESPB) does not target specific nerves, so the analgesic effect may differ depending on the extent of diffusion of local anesthetic. Therefore, needle size, which can affect the diffusion of local anesthetic, may be an important factor in the analgesic effect. PATIENT CONCERNS: Four patients with end-stage renal disease on hemodialysis received vascular surgery due to arteriovenous fistula occlusion. Vascular bypass surgery was performed on the axillary vein. DIAGNOSES: Four patients with end-stage renal disease on hemodialysis were diagnosed with arteriovenous fistula occlusion. One in 4 patients was diagnosed with diaphragm paralysis after ESPB, and the other 3 did not develop diaphragm paralysis. INTERVENTIONS: ESPB was conducted by ultrasound using a 25- or 22-gauge needle at the C7 level. The extent of nerve blockade was determined based on cold sensation, and diaphragm excursion and thickness were measured via ultrasound. OUTCOMES: The analgesic effect was excellent in 2 patients treated using a 22-gauge needle, but was poor in 2 other patients treated with a 25-gauge needle. LESSONS: ESPB at the C7 level can cause diaphragm paralysis, and needle size may affect the extent of diffusion of local anesthetic.