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A Prospective Randomized Comparison of Ultrasound Guidance Versus Neurostimulation for Interscalene Catheter Placement
  1. Michael J. Fredrickson, MD*,,
  2. Craig M. Ball, MD and
  3. Adam J. Dalgleish, MD§
  1. From the *Department of Anesthesia, Auckland City Hospital;
  2. Department of Anesthesiology, Faculty of Medical and Health Sciences, University of Auckland;
  3. Department of Orthopedic Surgery, Auckland City Hospital; and
  4. §Department of Orthopedic Surgery, Middlemore Hospital, Auckland, New Zealand.
  1. Address correspondence to: Michael J. Fredrickson, MD, Anesthesia Institute, PO Box 109 199, Newmarket, Auckland, New Zealand (e-mail: fredrickson{at}


Background and Objectives: Ultrasound (US) imaging facilitates catheter placement adjacent to the most appropriate elements of the brachial plexus, which for shoulder surgery are the C5-C6 roots or superior trunk. Therefore, it was investigated whether such placement would improve catheter effectiveness compared to placement with traditional techniques.

Methods: Needles introduced for catheter insertion were prospectively randomized to either US guidance immediately lateral to the C5-C6 roots/superior middle trunks (n = 43) or neurostimulation (NS) guidance to an appropriate motor response at less than 0.5 mA (n = 40). Ropivacaine 0.5% 30 mL was administered via the catheter before surgery under general anesthesia. After surgery, ropivacaine 0.2% infusion at 2 mL/hr with on-demand 5-mL boluses via an elastomeric pump was continued at home for 2 to 5 days. Patients were questioned regarding the need for ropivacaine boluses, tramadol, and numerical rating pain score (NRPS) on postoperative days 1 and 2.

Results: Catheter interventions for an NRPS of greater than 2 (0-10) in recovery were lower in the US group (US = 2/43, NS = 10/39; P = 0.007). Day 1 median ropivacaine bolus consumption (US = 1, NS = 2; P = 0.03) and the proportion of subjects requiring 2 or more tramadol tablets (US = 2/43, NS = 7/39; P = 0.04) were lower in the US group. These differences were not present on day 2. Postoperative pain was similar in both groups. Median (quartiles) needle time under the skin was lower in the US group (49 secs [41-55 secs]) than the NS group (97 secs [80-137 secs]) (P < 0.001) and was associated with a 1-point reduction in procedural NRPS (median [quartiles]: US = 2 [1-4], NS = 3 [2-6]; P = 0.002).

Conclusions: After shoulder surgery, interscalene catheters placed with US demonstrated improved effectiveness during the first 24 hrs compared with those placed with NS. These catheters were also placed with less needling and a very small reduction in procedure-related pain.

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  • This work was supported by a grant from the I-Flow Corporation, Lake Forrest, Calif.

  • This study was presented at the New Zealand Society of Anaesthetists Annual Meeting "Ritchie Prize Session", October 11-14, 2008, Wellington, New Zealand; and the American Society of Regional Anesthesia Annual Spring Meeting "Best of Abstracts Session", May 1, 2009, Phoenix, Arizona.