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Validation of the soft-embalmed Thiel cadaver as a high-fidelity simulator of pressure during targeted nerve injection
  1. Graeme McLeod1,2,
  2. Shengli Zihang2,
  3. Amy Sadler3,
  4. Anu Chandra2,
  5. Panpan Qiao4,
  6. Zhihong Huang2 and
  7. Christine Demore5
  1. 1Department of Anaesthesia, Ninewells Hospital, Dundee, UK
  2. 2Institute of Academic Anaesthesia, University of Dundee, Dundee, UK
  3. 3Department of Anaesthesia, Ninewells Hospital and Medical School, Dundee, UK
  4. 4Department of Bioengineering, University of Dundee, Dundee, UK
  5. 5Department of BioPhysics, Sunnybrook Research Institute, Toronto, Ontario, Canada
  1. Correspondence to Professor Graeme McLeod, Department of Anaesthesia, Ninewells Hospital, Dundee DD1 9SY, UK; g.a.mcleod{at}


Introduction Although administration of regional anesthesia nerve blocks has increased during the COVID-19 pandemic, training opportunities in regional anesthesia have reduced. Simulation training may enhance skills, but simulators must be accurate enough for trainees to engage in a realistic way—for example, detection of excessive injection pressure. The soft-embalmed Thiel cadaver is a life-like, durable simulator that is used for dedicated practice and mastery learning training in regional anesthesia. We hypothesized that injection opening pressure in perineural tissue, at epineurium and in subepineurium were similar to opening pressures measured in experimental animals, fresh frozen cadavers, glycol soft-fix cadavers and patients.

Methods We systematically reviewed historical data, then conducted three validation studies delivering a 0.5 mL hydrolocation bolus of embalming fluid and recording injection pressure. First, we delivered the bolus at 12 mL/min at epimysium, perineural tissue, epineurium and in subepineurium at 48 peripheral nerve sites on three cadavers. Second, we delivered the bolus at using three infusion rates: 1 mL/min, 6 mL/min and 12 mL/min on epineurium at 70 peripheral nerve sites on five cadavers. Third, we repeated three injections (12 mL/min) at 24 epineural sites over the median and sciatic nerves of three cadavers.

Results Mean (95%) injection pressure was greater at epineurium compared with subepineurium (geometric ratio 1.2 (95% CI: 0.9 to 1.6)), p=0.04, and perineural tissue (geometric ratio 5.1 (95% CI: 3.7 to 7.0)), p<0.0001. Mean (95%) injection pressure was greater at 12 mL/min compared with 1 mL/min (geometric ratio 1.6 (95% CI: 1.2 to 2.1), p=0.005). Pressure measurements were similar in study 3 (p>0.05 for all comparisons).

Discussion We conclude that the soft-embalmed Thiel cadaver is a realistic simulator of injection opening pressure.

  • technology
  • education
  • patient simulation

Data availability statement

All data relevant to the study are included in the article or uploaded as supplementary information. Data are available from GML on request at

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Data availability statement

All data relevant to the study are included in the article or uploaded as supplementary information. Data are available from GML on request at

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  • Correction notice This article has been corrected since it published Online First. Figure 5 has been replaced.

  • Contributors GML and CD designed the study and wrote the paper ZH was grant holder and supervised SZ’s and PQ’s PhD studies SZ, AS, AC and PQ conducted the study GM and CD supervised AC’s PhD studies GM supervised AS, regional fellow.

  • Funding The study was funded by Tenovus, Tayside.

  • Competing interests GML is a member of the Braun/Philips Regional Anaesthesia Scientific Advisory Panel. He has received grants for research and presentation at conferences.

  • Provenance and peer review Not commissioned; externally peer reviewed.