title: Ultrasound- or nerve stimulation-guided wrist blocks for carpal tunnel release: a randomized prospective comparative study.
abstract: OBJECTIVE
  We hypothesized that ultrasound-guided wrist blocks may be faster to perform, and may increase success rate, compared with nerve stimulation-guided wrist blocks.
  
  
  METHODS
  Sixty patients undergoing ambulatory endoscopic carpal tunnel release were randomly allocated to receive median and ulnar nerve blocks using either sensory-motor nerve stimulation (n = 30) or ultrasound guidance (n = 30). Four mL of mepivacaine 1.5% was injected around each nerve. Performance time and onset time of complete sensory block were assessed.
  
  
  RESULTS
  Median time to perform both median (ultrasound, 55 [48-60] vs. nerve stimulation, 100 [65-150] seconds, P = .002) and ulnar (ultrasound, 57 [50-70] vs. nerve stimulation, 80 [60-105] seconds, P = .02) nerve blocks were significantly shorter in the ultrasound group. Onset time of complete sensory block in the median (ultrasound, 370 [278-459] vs. nerve stimulation, 254 [230-300] seconds, P = .02) and ulnar (ultrasound, 367 [296-420] vs. nerve stimulation, 241 [210-300] seconds, P = .01) nerve areas were shorter in the nerve stimulation group. The success rate was 93% in both groups.
  
  
  CONCLUSIONS
  This randomized prospective study demonstrates that ultrasound-guided wrist nerve blocks are as efficient as those performed with nerve stimulation.
authors.affiliation: Department of Anesthesiology, Dubai Medical Suites, Dubai Healthcare City, UAE. phmacaire@hotmail.com
authors.forename: Philippe
authors.initials: P
authors.lastname: Macaire
authors.forename: François
authors.initials: F
authors.lastname: Singelyn
authors.forename: Patrick
authors.initials: P
authors.lastname: Narchi
authors.forename: Xavier
authors.initials: X
authors.lastname: Paqueron
mesh_terms: D000328:Adult; D000368:Aged; D002349:Carpal Tunnel Syndrome / Q000601:surgery*; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000000981:diagnostic imaging*; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D011446:Prospective Studies; D016037:Single-Blind Method; D013997:Time Factors; D014459:Ulnar Nerve / Q000000981:diagnostic imaging*; D014463:Ultrasonography; D014953:Wrist / Q000294:innervation*