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

In this study, we measured the performance of medical students and anaesthetists using a new tracker needle during simulated sciatic nerve block on soft embalmed cadavers. The tracker needle incorporates a piezo element near its tip that generates an electrical signal in response to insonation. A circle, superimposed on the ultrasound image surrounding the needle tip, changes size and colour according to the position of the piezo element within the ultrasound beam. Our primary objective was to compare sciatic block performance with the tracker switched on and off. Our secondary objectives were to record psychometrics, procedure efficiency, participant self-regulation and focused attention using eye-tracking technology. Our primary outcome measures were the number of steps successfully performed and the number of errors committed during each block. Videos were scored by trained experts using validated checklists. Sequential tracker activation and deactivation was randomised equally within subjects. With needle activation, steps improved in 10 (25%) subjects and errors reduced in six (15%) subjects. The most important steps were: needle tip identification before injection, OR (95%CI) 2.12 (1.61-2.80; p < 0.001); and needle tip identification before advance of the needle, 1.80 (1.36-2.39; p < 0.001). The most important errors were: failure to identify the needle tip before injection, 2.40 (1.78-3.24; p < 0.001); and failure to quickly regain needle tip position when tip visibility was lost, 2.03 (1.5-2.75; p < 0.001). In conclusion, needle-tracking technology improved performance in a quarter of subjects.

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.

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.

Compensable back pain and migrants.

Ten years of cases of compensable back pain from a rehabilitation centre were reviewed for evidence that is relevant to the strongly negative stereotypes that are held commonly about migrant workers. The prevalence of migrant workers with back injuries was found to be similar to that in the occupations with higher accident liabilities in the surrounding municipalities. The relative proportion of musculoligamentous injuries and the more objectively confirmable back injuries was not related to the country of birth. Better predictors of treatment outcome were: the time that had elapsed between the injury and admission to the Centre; whether the referral was direct or indirect after the previous treatment; and the degree of fluency in English. It is concluded that the stereotypes that describe migrant workers as accident-prone or malingerers cannot be supported and that the vulnerability of migrant workers to the "accident-victim syndrome" can be accounted for without reference to ethnic characteristics.