title: Enhanced visual acuity with echogenic needles in ultrasound-guided axillary brachial plexus block: a randomized, comparative, observer-blinded study.
abstract: BACKGROUND
  We prospectively evaluated the effect of insertion angle on the visibility of echogenic and nonechogenic needles in phantoms and in axillary nerve blocks in patients.
  
  
  METHODS
  Conventional and echogenic needles were studied in phantoms at insertion angles of 0-30°, 30-45°, and ≥ 45°. Operators rated comfort and image quality during the procedure and experts blinded to the needle groups randomly analyzed videos for tip and shaft visibility, surrounding tissue visibility, sharpness of the needle surface, and percentage of time with the needle completely visible. Patients scheduled for axillary nerve block were prospectively enrolled in the clinical study. Needle insertion angles were 0-30° for the median nerve approach, 30-45° for the radial nerve, and ≥ 45° for the musculocutaneous nerve. The same needle parameters were analyzed during the procedure and on videos.
  
  
  RESULTS
  Physician comfort and image quality were significantly better for echogenic needles for phantoms and patients at 30-45° and ≥ 45° insertion angles. Needle tip and shaft visibility at 30-45° and ≥ 45° insertion angles in phantoms and for the musculocutaneous nerve in patients were significantly improved, as well as the percentage with complete needle visualization during the procedure. Tissue visibility and needle sharpness were significantly superior for conventional needles. There were no differences concerning block parameters and adverse events.
  
  
  CONCLUSIONS
  Needles with enhanced echogenicity improved physician comfort, image quality, needle visibility, and visualization time of the needle during ultrasound-guided procedures in phantoms and axillary nerve blocks using insertion angles of 30-45° and ≥ 45°.
authors: Department of Anesthesiology and Critical Care Medicine, Montpellier University Hospital and University Montpellier 1, Montpellier, France - x-capdevila@chu-montpellier.fr.
authors: B
authors: B
authors: Abbal
authors: O
authors: O
authors: Choquet
authors: A
authors: A
authors: Gourari
authors: N
authors: N
authors: Bouic
authors: A
authors: A
authors: Massone
authors: P
authors: P
authors: Biboulet
authors: S
authors: S
authors: Bringuier
authors: X
authors: X
authors: Capdevila
mesh_terms: D000328:Adult; D001917:Brachial Plexus / Q000000981:diagnostic imaging*; D065527:Brachial Plexus Block / Q000379:methods*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009339:Needles; D009407:Nerve Block / Q000379:methods*; D019047:Phantoms, Imaging; D011446:Prospective Studies; D018084:Ultrasonography, Interventional