title: Comparative evaluation of the visibility and block characteristics of a stimulating needle and catheter vs an echogenic needle and catheter for sciatic nerve block with a low-frequency ultrasound probe.
abstract: BACKGROUND
  Clear visibility of the needle and catheter tip is desirable to perform safe and successful ultrasound-guided peripheral nerve blocks. This can be challenging with deeper blocks in obese patients. This study compared the visibility of echogenic and non-echogenic block needles and catheters in proximal sciatic blocks when performed with a low-frequency curved probe.
  
  
  METHODS
  Seventy-eight patients undergoing total knee joint arthroplasty were randomized to receive an ultrasound-guided continuous sciatic nerve block using either a non-echogenic needle and stimulating catheter or an echogenic needle and echogenic non-stimulating catheter. Block needles in both groups were placed using both neurostimulation and ultrasound guidance, after which the catheter was positioned using either neurostimulation alone (Stimulating group) or imaging alone (Echogenic group). Three anaesthetists blinded to group allocation graded video clips recorded during the blocks for nerve, needle and catheter visibility. Performance characteristics and block parameters were also compared.
  
  
  RESULTS
  No significant differences between the two groups were observed with regard to needle or catheter visibility (P=0.516). The Stimulating group required more needle redirections (P=0.009), had a longer procedure time [Echogenic median 274 s vs Stimulating 344 s (P=0.016)], and resulted in greater patient discomfort (P=0.012). There were no significant differences between the two groups in terms of block onset or completion time.
  
  
  CONCLUSIONS
  Use of echogenic needles and catheters reduced procedure time and patient discomfort compared with a stimulating catheter system. There were no differences in the visibility scores of the two systems.
  
  
  BACKGROUND
  CTR Protocol ID: R-11-495, Clinical Trials.Gov ID: NCT 01492660.
authors.affiliation: Department of Anesthesiology and Perioperative Medicine, London Health Sciences Centre, University Hospital, Western University, London, Ontario, Canada jonathan.brookes@lhsc.on.ca.
authors.forename: J
authors.initials: J
authors.lastname: Brookes
authors.affiliation: Department of Anesthesiology and Perioperative Medicine, London Health Sciences Centre, University Hospital, Western University, London, Ontario, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Sondekoppam
authors.affiliation: Department of Anesthesiology and Perioperative Medicine, London Health Sciences Centre, University Hospital, Western University, London, Ontario, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Armstrong
authors.affiliation: Department of Anesthesia, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: V
authors.initials: V
authors.lastname: Uppal
authors.affiliation: Department of Anesthesiology and Perioperative Medicine, London Health Sciences Centre, University Hospital, Western University, London, Ontario, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Dhir
authors.affiliation: Department of Anesthesiology and Perioperative Medicine, London Health Sciences Centre, University Hospital, Western University, London, Ontario, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Terlecki
authors.affiliation: Department of Anesthesiology and Perioperative Medicine, London Health Sciences Centre, University Hospital, Western University, London, Ontario, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Ganapathy
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000779:Anesthetics, Local / Q000008:administration & dosage; D019645:Arthroplasty, Replacement, Knee; D002406:Catheterization, Peripheral / Q000379:methods; D004311:Double-Blind Method; D004558:Electric Stimulation / Q000295:instrumentation / Q000379:methods; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009339:Needles; D009407:Nerve Block / Q000295:instrumentation / Q000379:methods*; D010147:Pain Measurement / Q000379:methods; D010149:Postoperative Pain / Q000517:prevention & control; D012584:Sciatic Nerve / Q000000981:diagnostic imaging*; D018084:Ultrasonography, Interventional / Q000295:instrumentation / Q000379:methods*
chemical_list: D000779:Anesthetics, Local
keywords: acute pain; equipment, needles; equipment, ultrasound machines; regional anaesthesia; regional techniques