A New Model for Training on Human Specimens
in Surgical-Anatomical Skills Labs
HP Theeuwes1,2*, MPJM van Riel1, JF Lange1,3 and GJ Kleinrensink1
1Department of Neuroscience-Anatomy, Erasmus University Medical Centre, Netherlands
2Department of Surgery, Zuyderland Hospital, Netherlands
3Department of Surgery, Erasmus University Medical Centre, Netherland
Submission: July 07, 2017; Published: July 18, 2017
*Corresponding author: HP Theeuwes, Department of Neuroscience-Anatomy, Erasmus University Medical Centre Rotterdam, P.O. Box 2040, 3000, Rotterdam, Netherlands, Tel: +31-6-18112401; Fax: +31-10-7043257; Email: firstname.lastname@example.org
How to cite this article: HP Theeuwes, MPJM van R, JF Lange, GJ Kleinrensink. A New Model for Training on Human Specimens in Surgical-Anatomical
Skills Labs. Anatomy Physiol Biochem Int J. 2017; 3(1): 555604. DOI:10.19080/APBIJ.2017.03.555604.
Introduction: Surgical-anatomical training on human specimens is one of the aspects for medical education, more specific surgical education. Before these specimens can be used for educational purposes they need to be preserved. There are different methods preserving human remains for those donated their body to science. Formaldehyde embalming is most frequently used and is well suited for learning and teaching gross anatomy. Learning anatomy related to surgical procedures on embalmed bodies is rather difficult because of the rigidity after fixation. This new method makes it possible to fixate human bodies for years but without the usual disadvantages of rigidity. It is made possible to perform and teach all kind of surgical interventions. The rigidity of the wrist was used to compare the differences in flexibility between non-embalmed, normally embalmed and bodies embalmed with this new method.
Materials and Method: Conventional formalin embalmed arms and arms embalmed with our new method were compared with fresh frozen (non-embalmed) arms. Force measurements were performed on single, embalmed, undissected arms. The used size for rigidity of the wrist was the force needed to start flexion (movement) of the hand, Newton Metre, to reach a predefined angle.
Results: In total nineteen human arms were measured. The arms embalmed with the new method showed comparable results with the non-embalmed arms upon 30 degrees of wrist flexion. Fresh frozen arms remain more flexible above 15 degrees of wrist flexion compared with both groups. In 30 degrees and more, the formalin embalmed arms showed significantly higher rigidity when compared with the new method embalmed arms.
Conclusion: The results show a significant decrease in joint stiffness of the wrist in the NCA embalmed bodies when compared with conventional formalin embalmed bodies. Although the flexibility is not the same when compared with non-embalmed bodies, the benefits of this new method are useful in performing surgical interventions and the making of dynamic anatomical models on a larger scale without the disadvantages of fresh frozen or ‘light’ embalmed specimen. The method described to measure the flexibility of the wrist can be used as a calibrated instrument to give value to the flexibility after and before embalming.
Embalming human bodies is of all times, after the introduction of formaldehyde fixation for organic tissues in 1893 by the German physician Ferdinand Blum, the donated bodies could be used more efficiently for gross anatomy purposes than before Fox et al. . Nowadays the demand for (embalmed) human bodies used for surgical training, besides normal anatomy teaching, has increased. Mostly fresh frozen human bodies, donated for science, are used for surgical trainings. Its realistic tissue handling and flexibility represent the main advantages of fresh frozen human bodies. The disadvantages however are also well known: risk of infection (additional testing is essential), degeneration, time pressure and single use are only some examples. The introduction of “light” or “soft’ embalming methods like Thiel’s, Duke’s or other new method’shave contributed to prolonging the natural characteristics of the donated bodies Thiel et al. [2-8]. All of these methods have made it possible to re-use embalmed bodies for multiple purposes. It is now possible to use the bodies more efficiently because they can be used multiple times. These new methods slow down the degeneration process for weeks without losing their natural characteristics. Still these methods were not developed for long time fixation and conservation of human flexible characteristics.Methods developed for long-term embalming and the remaining
of flexibility like Complucador Anubi are less well known.
In our institution multiple methods have been tried, but none
of these methods had the capacity of remaining for H.P. Come
he bodies sufficiently flexible and stopped the degeneration of
the bodies completely. A tour around most of our anatomical
departments in the Netherlands confirmed our findings. Since
the demand of flexible bodies for surgical training increased we
started our search for developing a new embalming method that
would guaranty enough fixation to stop the degeneration process,
but would remain the near normal flexibility characteristics
of the body. At Erasmus MC, the University Medical Centre
Rotterdam, a large university hospital with an internationally
oriented surgical training centre, the demand for fresh frozen
bodies increased over the years. Since these bodies only last for
one or two days after thawing, the capacity for training surgical
residents decreased over time. For specialised courses, research
and educational purposes as a rule only fresh frozen body-parts
are used instead of complete bodies. Usually refreezing of the
unused parts is an inferior option since the tissues continue to
degenerate. Embalming with formaldehyde, phenol or alcoholglycerine
fixation can prevent this process. However, the
main disadvantages of these methods are the increased tissue
stiffness and the lack of colour preservation. We developed
a new embalming agent, in the article referred to as: New
Conditioning Agent (NCA), a combination of a novel pre-rinse
formula plus formalin embalming. With this new embalming
agent the embalmed human bodies are less stiff when compared
with the standard formalin method. In a previous publication by
our research group ‘proof of principle’ was shown with regard
to endoscopic procedures. However no data could be published
about the objectively measured flexibility of the joints, which in
our perspective is of great importance in surgical training and
functional research of the locomotor system.
The aim of this study was to objectively show this advantage
under standardized experimental conditions. We compared
two embalming methods, formaldehyde and NCA, with the
“gold standard”, i.e. fresh frozen human bodies, with regard to
mechanical tissue aspects (rigidity). Not many experiments have
been conducted to measure the flexibility of embalmed human
bodies. Since the flexibility of the joints and tissue quality is
of great importance for performing surgical interventions we
introduce a new method for measuring joint flexibility. Instead
of only using a standard protractor, also the force needed to do
so was also taken into account. The wrist-joint movement was
This is an easily accessible joint.
The measurements could be controlled and repeated easily.
This joint was amply available in our laboratory.
Furthermore, this joint has been reported in other papers
and hence comparison with previous data was easier.
Last but not least the wrist joint is of clinical/surgical
importance. Because of the complexity of the anatomy and the
trauma treatment of this delicate joint complex, training of
surgical techniques during hand-wrist courses in the dissection
room becomes more and more important.
Bodies from deceased persons who donated their body for
education and science at our institution were embalmed at room
temperature between 24-48 hours post-mortem. Embalming was
regularly performed via two annuals fixated in the right femoral
artery, one in cranial direction (‘up stream’) and one in caudal
direction (‘down stream’). A perfusion pressure of 150 mmHg
was used. After perfusion, the human bodies were immersed
in a 4,4% formaldehyde solution for at least four months
(described in more detail in experiment section), the latter to
ensure thorough fixation of the skin and intestinal organs. After
this period the fixated human bodies were transferred for at
least two months to a conservation container, and immersed
in a 1% phenoxy-ethanol solution. The human bodies remain
immersed in these containers until they are needed for research
or education purposes.
Two embalming methods were compared with nonembalmed
“fresh frozen” human arms. The first method: using
a 4,4% formaldehyde (11% formalin) embalming solution,
consists of 0,2M phosphate buffer (pH7,4-7,6), 1000 grams
Na2SO4•10 H2O, 500 grams NaCl, 10 litres of 86.5% glycerol, 6
litres 37% formaldehyde and replenished with Millia water to
a total of 50 liters. The second (experimental) method: NCA
embalming is a combination of a novel pre-rinse formula plus a
4,4% formaldehyde embalming solution, as described in the first
method. After admission of the pre-rinse solution, a 30 minutes
incubation interval was added followed by light manipulation of
the skin and flexion of the joints. Embalming was furthermore
performed as described above in the embalming section. In total,
six (3 left, 3 right) 4,4% formaldehyde embalmed and eight NCA
(5 left, 3 right) embalmed arms were compared with five fresh
frozen arms (1 left, 4 right). The formaldehyde group consisted
of three left and three right arms from four different bodies
(1 female, 5 males; mean age 83:SD7). The second NCA group
consisted of five left and three right arms from five different
bodies (6 females, 2 males; mean age 80:SD14). For the fresh
frozen group four right and one left arm were available from
three different bodies (5 females; mean age 82:SD15).
Serotonin precursor (5-Hydroxytryptophan) was obtained
from May and Baker United Kingdom, and used for the study.
From the estimation of the powdered 5-Hydroxytryptophan
(serotonin precursor) content of cooked and uncooked beans
according to the method of Feldman JM, Lee . As modified
by Mosienko et al. . The serotonin precursor diet was prepared
by mixing 40mg (0.04g) of the precursor in hundred gram
(100g) of the feed.0ne gram (1g) of the mixture was mixed with
99g of the feed. So that the amount of 5HTP added was equivalent
to that contained in the beans diet? An electric blender was
used to blend the mixture to form the serotonin precursor diet.
Single, embalmed, un-dissected (detached) arms were
fixated in a setup with Velcro straps (Figure 1). The proximal
parts of the arms were fixated in a semi-circular plastic pipe, with
the arms positioned in supination (volar side directed upwards).
The hand was strapped on a Plexiglas board. The Plexiglas board
had a length of 25 cm and weighted 675 grams. A stainless steel
(traction) wire was attached to the board and guided through
the centre of a small whole 5 cm above the board, ensuring an
upward directed force that was continuously perpendicular to
the Plexiglas board (Figure 1). The other end of the wire was
connected to a force transducer. For all measurements the
distance between the rotation axis and the point of application
of the force was 25 cm. A measure for the stiffness of the wrist
is the force needed to start flexion (movement) of the hand. We
measured the forces at predefined angles; 0, 15, 30, 45, 60 and
75 degrees. Before every measurement the hand was positioned
in the predefined angle on the Plexiglas board with a protractor.
The protractor was adjusted before each measurement to
indicate the right corresponding angles.
1. Fixation of the arm, 2. Fixation hand on the Plexiglas board, 3.
Protractor (attached for illustration purposes) 4. Traction wire, 5. CPU
digital force gauge transducer.
The rotational stiffness is defined as the applied moment for
one degree of rotation. Figure 2 give a schematic overview to
visualize the corresponding forces and the torque of these forces.
The force needed to start rotating the hand (Fpull) was the force
needed to lift the hand (Fhand) and Plexiglas board (Fboard) and
necessarily to exceed the rotational stiffness of the wrist. The
moment arm (c) of this force was constant in al measurements
(= 25 cm) because the pulling force was always perpendicular to
the Plexiglas board. In the situation that the wrist joint was an
ideal joint without any friction then Fpull could be calculated by:
Fpull · c = Fboard · b · cos(α) + Fhand · a · cos(α)
If there was a certain resistance against rotation in the joint
because of stiffness in the wrist then an extra moment (Mstiffness)
would have to be overcome. In that situation the pulling force
Fpull · c = Fboard · b · cos(α) + Fhand · a · cos(α)+ Mstiffness
Since the body weight of the different bodies was not known
in our experiment an average value of the weight of the hand, the
mass of the hand (0,4% of total body weight from an estimated
80 kilograms) and the position of the centre of gravity of the
hand in relation to the wrist joint were found in Chaffin .
DINED Anthropometric database. Standard values of the mass of
the hand and the distance to the rotation axis in the wrist joint
are given in Table 1.The force was measured with a commercially
available force transducer (AIKOH CPU digital force gauge,
9000 series 50kgf, Aikoh engineering Co. LTD, Osaka, Japan).
The peak-hold function of the force transducer was used in
order to measure the highest force needed to start the motion.
The maximal angle of 75 degrees was chosen in order to avoid
anatomical limitations to the motion.
The means were compared using Mann-Whitney’s U test.
Multi-variant regression analysis was used to test the influence
of gender and side on the moments needed for flexion of the
wrists. The embalming technique was put in the model as
In total nineteen human arms were measured from twelve
different bodies. The average forces (± SD) needed to flexion the
wrist at different angles are presented for NCA, formaldehyde
embalmed bodies and for fresh frozen bodies (Table 1). With the
newly developed embalming liquid NCA the pulling force was
in all positions significantly lower when compared to the forces
needed in the arms embalmed with formaldehyde, except at the
zero degrees position. As can be seen in (Figure 3), the pulling
force needed in the NCA group was statistically significant
higher when compared to fresh frozen bodies except in the
positions at zero and fifteen degrees. Figure 3 shows the average
force corrected for the weight of the hand and the weight of the
Plexiglass board. The fresh frozen bodies showed no significant
increase or decrease in force needed to flex the wrist during the
experiments. A significantly lower force was needed to flex the
arms at 30°, 45°, 60° and 75° in favour of the NCA (purple line)
when compared with conventional (formalin) embalming (red
line). No significant difference was observed at 0° and 15°.
Both groups needed significantly more force to move the
wrist at 30°, 45°, 60° and 75° when compared with the fresh
frozen, reference group (yellow line), see 1). The embalmed
bodies with the NCA were two/ three times more flexible
than the formaldehyde embalmed bodies. The traditionally
embalmed bodies were 50 till 60% stiffer when compared to
NCA embalming. Multi-variant regression analysis between
groups for gender (p=0,782) and side (p=0,782) did not differ
Training on fresh frozen bodies is the method of choice
in most surgical training situations. However, several major
disadvantages make this a model, which cannot be used
in a setting in which large quantities are needed, i.e. in an
international training centre or shortage of freezers. To test
whether a new method of embalming could be an alternative or
complementary for fresh frozen bodies, flexibility experiments
were performed on fresh frozen anatomical specimen and the
results were compared with the results of tests on formaldehyde
embalmed and NCA prepared bodies. For which a new, specific,
measurement tool was developed. When compared to formalinembalmed
bodies, NCA bodies showed a significantly higher
In Figure 3 is shown that NCA embalmed bodies were two
to three times more flexible than formalin-embalmed specimen.
Although the colour preservation and hence the problem of
discrimination between structures were not mentioned in
this paper, it is generally known that anatomical structures in
embalmed bodies can be differentiated less easy than in vivo or
in fresh frozen specimen. This of course is due to loss of colour,
which in turn is due to loss of erythrocytes and the embalming
process itself. NCA has the tendency to be more realistic than
formalin embalming regarding colour and tissue handling.
Presently we are conducting experiments in which we add
colorants to solve this problem.
In our department of anatomy there is an increasing demand
for postgraduate (surgical) education, mainly with regard to
teaching and training of new surgical techniques; application of
prosthesis, fracture management and laparoscopic operations.
One of the main advantages besides flexibility is the ample, quick
and easy availability of flexible, embalmed human bodies. In
case of serious specific pathology quick and easy replacement
of a body is an advantage, which cannot be underestimated.
The conventional formalin embalming method can still be used for standard dissection courses, which mainly focuses on static
study of gross anatomy. In our institution fresh frozen bodies
were usually used for courses regarding the human locomotor
system and abdominal interventions.
NCA embalmed human bodies however have successfully
replaced fresh frozen bodies at our institution. Furthermore the
systemic perfusion with NCA also increases the quality of brain
tissue, making brain surgery interventions possible, which could
not be performed before, e.g. certain skull base approaches. An
increasing demand for new and realistic (laparoscopic) surgicalanatomical
training facilities have encouraged us to continue
exploring new applications with this new promising method
Slieker et al. , Klitsie et al . Currently we are conducting
a study in which no formalin is being used, first results are
promising Brenner , Hayashi S .
The results show a significant decrease in joint stiffness of
the wrist in the NCA embalmed bodies when compared with
conventionally (formaldehyde) embalmed bodies. Even though
the NCA embalmed bodies did not fully meet the flexibility of
‘gold standard’, i.e. fresh frozen bodies, it remains a remarkable
improvement compared with the standard formalin embalming
method. Taken into account that these bodies can be conserved
for several years without losing their specific characteristics and
will not decay, the NCA preservation method can be considered
a useful alternative or complementary method to fresh frozen
bodies in the anatomy and surgical training labs. Especially for
those institutions or countries not using freezers. The method
described to measure the flexibility of the wrist can be used as
a calibrated instrument to give value to the flexibility after and
The authors would like to thank: the people and their next
of kin for donating their bodies for science at our Neuroscience-
Anatomy Department making this research possible. Ms Yvonne
Steinvoort, prosector, for extended help during the embalming
process. Tim de Jong, MD, PhD. for his assistance on the data
analysis and table presented in this article, Alex Poublon and
Ante Prkic for their assistance on the data acquisition and all
members of the EARP-student team (www.earprotterdam.nl) for
their effort and enthusiasm during this project.