An initial evaluation of the effect of a novel regional block needle with tip‐tracking technology on the novice performance of cadaveric ultrasound‐guided sciatic nerve block

Abstract

Summary Visibility of the needle tip is difficult to maintain during ultrasound‐guided nerve block. A new needle has been developed that incorporates a piezo element 2–2.3 mm from the tip, activated by ultrasound. The electrical signal manifests as a coloured circle surrounding the needle tip, and allows real‐time tracking. We hypothesised that novice regional anaesthetists would perform nerve block better with the tracker turned on rather than off. Our primary objective was to evaluate the new needle by measuring the performance of novice anaesthetists conducting simulated sciatic block on the soft embalmed Thiel cadaver. Training consisted of a lecture, scanning in volunteers and practice on cadavers. Testing entailed scanning the sciatic nerve of a cadaver and conducting 20 in‐plane sciatic blocks in the mid‐to‐upper thigh region. Subjects were randomised equally, in groups of five, according to the sequence: tracker on/off/on/off; or tracker off/on/off/on. Video recordings were assessed by six raters for steps performed correctly and errors committed. Eight subjects were recruited and 160 videos were analysed. Using the tracking needle, five correct steps improved and one error reduced. The benefits included: better identification of the needle tip before advancing the needle, OR (95%CI) 3.4 (1.6–7.7; p < 0.001); better alignment of the needle to the transducer, 3.1 (1.3–8.7; p = 0.009); and better visibility of the needle tip 3.0 (1.4–7.3; p = 0.005). In conclusion, use of the tracker needle improved the sciatic block performance of novices on the soft embalmed cadaver.

Ultrasonographic needle tip tracking for in-plane infraclavicular brachialis plexus blocks: a randomized controlled volunteer study

“…McLeod et al showed that the Onvision tracking technology can improve the performance of unexperienced anesthesiologists when conducting in-plane sciatic blocks in a cadaver study. 13 Accordingly, McVicar et al showed a significant improvement of technical needling skills of novice trainees in an ex vivo model when using an electromagnetic needle tracking system. 14 Since our present study was performed in healthy volunteers, it was considered as ethically questionable and inappropriate to involve less experienced colleagues.…”

“…19 While tofu, gelatin or muscle tissue phantoms provide acceptable feel for tissue and ultrasound attenuation, cadavers are considered as anatomically most relevant. 13 However, block success, failure rates, or adverse events must be estimated indirectly in these models. 3 As a first in human testing of the Onvision needle tip tracking technology, we considered a volunteer trial appropriate.…”

The effect of an ultrasound‐activated needle tip tracker needle on the performance of sciatic nerve block on a soft embalmed Thiel cadaver

“…Forty subjects then conducted sciatic block on one out of three soft embalmed cadavers ( We used a within-subjects experimental model: each subject was exposed equally to the activated or nonactivated tracker needle and randomised by computer software to one out of two sequences (Fig. 1 We used data from our previous study [7] to power the current study. In that, there was a median difference of 2.…”

“…Our group has sought to improve training by using a soft embalmed Thiel cadaver simulator [5], application of mastery learning techniques [4], quantitative measurement of performance using validated checklists of steps and errors [6] and eye-tracking analysis [3,6,7]. The most difficult tasks encountered by trainees were viewing the needle tip at all times, recognition of needle-nerve contact and detection of intraneural injection [6].…”

“…Acoustic mechanical waves emitted from the ultrasound transducer compress the piezo element which generates an electrical signal. The signal is processed and represented on the ultrasound screen as a green circle surrounding the needle tip with the piezo element at its centre [7,9,10]. The radius of the green circle is greater than the distance between the tip and the centre of the piezo element, thus offering a margin of safety during needle advancement.…”