Physical properties and functional alignment of soft-embalmed Thiel human cadaver when used as a simulator for ultrasound-guided regional anaesthesia.
BACKGROUND
We evaluated the physical properties and functional alignment of the soft-embalmed Thiel cadaver as follows: by assessing tissue visibility; by measuring its acoustic, mechanical and elastic properties; by evaluating its durability in response to repeated injection; and by aligning images with humans.


METHODS
In four soft-embalmed Thiel cadavers, we conducted three independent studies. We assessed the following factors: (i) soft tissue visibility in a single cadaver for 28 weeks after embalming; (ii) the displacement of tissues in response to 1 and 5 ml interscalene and femoral nerve blocks in a single cadaver; and (iii) the stiffness of nerves and perineural tissue in two cadavers. We aligned our findings with ultrasound images from three patients and one volunteer. Durability was qualified by assessing B-mode images from repetitive injections during supervised training.


RESULTS
There was no difference in visibility of nerves between 2 and 28 weeks after embalming {geometric mean ratio 1.13 [95% confidence interval (CI): 0.75-1.68], P=1.0}. Mean tissue displacement was similar for cadaver femoral and interscalene blocks [geometric mean ratio 1.02 (95% CI: 0.59-1.78), P=0.86], and for 1 and 5 ml injection volumes [geometric mean ratio 0.84 (95% CI: 0.70-1.01), P=0.19]. Cadavers had higher intraneural than extraneural stiffness [Young's modulus; geometric mean ratio 3.05 (95% CI: 2.98-3.12), P<0.001] and minimal distortion of anatomy when conducting 934 left-sided interscalene blocks on the same cadaver throughout a 10 day period.


CONCLUSIONS
The soft-embalmed Thiel cadaver is a highly durable simulator that has excellent physical and functional properties that allow repeated injection for intensive ultrasound-guided regional anaesthesia training.
Manchester Royal Infirmary, Manchester, UK.
S
S
Munirama
Centre for Anatomy and Human Identification, University of Dundee, Dundee, UK.
R
R
Eisma
Intensive care Unit, Wythenshawe Hospital, South Manchester University Hospitals, Manchester, UK.
M
M
Columb
Department of Medical Physics.
G A
GA
Corner
Institute of Academic Anaesthesia, Ninewells Hospital & Medical School, Dundee, UK g.a.mcleod@dundee.ac.uk.
G A
GA
McLeod
D000765:Anesthesia, Conduction / Q000379:methods*; D000776:Anesthesiology / Q000193:education*; D002102:Cadaver; D004503:Education, Medical, Graduate / Q000379:methods*; D054459:Elasticity Imaging Techniques / Q000379:methods; D004615:Embalming / Q000379:methods*; D006801:Humans; D008422:Materials Testing / Q000379:methods; D013664:Teaching Materials; D018084:Ultrasonography, Interventional / Q000379:methods*
cadaver; elastography; regional anaesthesia; ultrasonography