Why is surgical training difficult

Technical simulation models in emergency surgical training - an alternative to live tissue training and human preparations?


In contrast to the increasing surgical specialization in Western health systems, the confrontation of surgeons with war-specific injury patterns in military and humanitarian missions abroad requires a broad spectrum of emergency surgical skills. Low case numbers in Germany limit training opportunities in routine clinical practice. Training on anesthetized large animal models (Live Tissue Training, LTT) and human body donors (Human Cadavers, HC) is associated with logistical, didactic and ethical challenges and concerns.

In emergency medical training, patient simulators (mannikins) have been in use both preclinically and clinically for decades and the learning success through simulation training has been adequately documented in both civil and military environments [1 - 3]. The further development of synthetic tissue simulants and anatomically appropriate organ systems with realistic bleeding properties could make these state-of-the-art technical simulation models (Human Patient Simulators, HPS) usable for the surgical training of emergency operations that rarely occur in everyday clinical practice. The aim of the present work was to define the requirements for HPS in emergency surgery training from a technical expert's point of view, to evaluate the world's leading simulation models and to compare them with the established training methods LTT and HC as part of the Bundeswehr's operational surgery course.


The evaluation took place in three stages. First, in a semi-structured, guideline-oriented focus group discussion (FGD) with instructors from the field surgery course and international experts, the requirements for the ideal HPS for surgical skills training were defined. The evaluation was carried out as a structured content analysis according to Mayring [4]. This panel of experts (n = 16) then evaluated the four world-leading HPS. Subsequently, two HPS, which were rated as most suitable in this evaluation, were evaluated by the course participants (n = 16) as part of the operational surgery course together with the LTT and HC simulation modalities established in the course. The evaluation was carried out using questionnaires (Likert scales 1 - 5) with regard to

  1. Feasibility and realism of defined emergency surgical maneuvers,
  2. anatomical and haptic realism,
  3. subjective expectation of competence (self-efficacy) and
  4. psychological stress on course participants due to the respective training modality.

The results were evaluated as a one-way analysis of variance (significance level α = 0.05) and the assessment was limited to purely formative levels 1 (reaction of the participants) and 2 (learning success) of the established evaluation model "4 level evaluation" according to Kirkpatrick [5 ].


Fig. 1: Training course participants on an HPS model (Image: T. Pulpanek, Berlin)
The requirements for technical simulation models defined in the focus group discussion are derived from the conditions of the care of a real trauma patient. The models must correctly represent the human anatomy and demonstrate realistic bleeding behavior in combination with physiological responses to the surgical procedure. The necessary high level of complexity when performing emergency surgical maneuvers therefore requires the use of "high-fidelity" models. In addition, cost efficiency and practicability must also be taken into account.

The evaluation of the four HPS showed a clear superiority of the simulation models of the companies Operative Experience Inc. (OE; North East, MD, USA) and Strategic Operations (SO; San Diego, CA, USA).

Prototypes of abdominal simulation models from both companies were included in the field surgery course and evaluated alongside LTT and HC. Compared to LTT and HC, both the feasibility and the realism of the previously defined maneuvers were consistently rated significantly worse for both HPS (p <0.001). These results are based on differences in the physical tissue properties of the simulation modalities, which influence the haptics as well as the cut and seam qualities of the tissues and organs. Here, too, there was a highly significantly better assessment of LTT and HC (p <0.001), with LTT doing slightly better than HC.

Tab. 1: Feasibility and realism of emergency surgical maneuvers on body donors (HC), animal model (LTT) and technical simulation model (OE or SO) (ANOVA = Analysis of Variance)

Body region











F (1.30) = 3.573

p = 0.068


F (1.28) = 24.442

p <0.001







F (3.60) = 18.474

p <0.001


F (3.56) = 43.352

p <0.001













F (2.45) = 32.439

p <0.001


F (2.42) = 53.548

p <0.001

The subjective expectation of competence with regard to the implementation of defined emergency surgical maneuvers showed a statistically highly significant increase (p <0.001) through participation in the field surgery course. In the self-assessment of the participants, the training at HPS resulted in a significantly lower subjective gain in knowledge than with the other two modalities (p <0.001). The subjective experience of stress during training did not differ significantly between the modalities (p = 0.251).

The moral concerns of the participants were significantly lower when working with technical simulation models than when working with LTT and HC (p <0.05).


In this pilot study, the previously defined requirements were met to varying degrees by the examined simulation modalities.

Fig. 2: Levels 1 and 2 of the evaluation according to Kirkpatrick and adaptation of the follow-up study EvaLiT3 based on the results of the pilot study
The examined HPS can be an element in the implementation of a practice-oriented team training in which damage-limiting trauma maneuvers are taught on the basis of various injury patterns. This is useful for inexperienced advanced training assistants both as preparation for more complex skills exercises (skill training) and for training difficult decision-making processes and setting surgical treatment priorities (scenario training). The degree of anatomical detail (anatomical boundary layers, ligamentous holding devices of organs) and the haptic realism of the tested HPS currently do not allow it to be used for training technically demanding maneuvers that require an exact human anatomy. These can currently only be achieved by HC and - to a defined extent and with a certain transfer service - by LTT. It should also be considered that the use of realistic HPS is associated with high additional costs (HPS >> HC> LTT), which can only be justified in the context of a structured curriculum.

Differences in the experience of stress during training using various simulation modalities and its effect on learning success must be examined in a follow-up study. Biomarkers (e.g. α-amylase in saliva) and other objectifiable parameters such as heart rate and heart rate variability should be included here. The same applies to the increase in self-efficacy as a positive predictive marker for learning success. In order to objectify the subjective learning success, independent external counselors should evaluate the skill level using validated scores.

The limitations of this study result in considerable optimization potential for follow-up examinations:

  • A lack of validated scores for testing in emergency surgery and the duality of this pilot study as a training and research event must be optimized in a follow-up study.
  • The relative homogeneity of the test group could be improved by restricting the group to further training in the first clinical section.
  • In the literature, simulation methods are currently mainly described and evaluated, which are based either on basic basic surgical (e.g. suture skills), laparoscopic or locally limited (e.g. otolaryngological skills) techniques or on non-surgical emergency measures (e.g. resuscitation , endotracheal intubation). There are no comparisons of HPS for emergency surgical training.

It is therefore essential to carry out further investigations.


  1. Capella J, Smith S, Philp A, et al. Teamwork Training Improves the Clinical Care of Trauma Patients. Journal of Surgical Education 2010; 67: 439-443.
  2. Steinemann S, Berg B, Skinner A, et al. In Situ, Multidisciplinary, Simulation-Based Teamwork Training Improves Early Trauma Care. Journal of Surgical Education 2011; 68: 472-477.
  3. Amin MR, Friedmann DR. Simulation-based training in advanced airway skills in an otolaryngology residency program. Laryngoscope 2013; 123: 629-634.
  4. Mayring P. Qualitative content analysis. Weinheim: Beltz Verlag; 2015.
  5. Kirkpatrick D.L. KJD. Evaluating Training Programs: The Four Levels. Oakland, CA, USA: Berrett-Koehler; 1994.

Leuntnant (SanOA) Katja Schneider
Email: [email protected]

Date: 25.01.2019