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Characterisation of Closed Soft Tissue Trauma with
a Focus on Changes to the Microvasculature
Zohreh Barani Lonbani1, Michael A. Schuetz1, 2, Roland Steck1
1Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology (QUT), Brisbane, Queensland, Australia
2Trauma Service, Princess Alexandra Hospital, Woolloongabba, Brisbane, Australia
Closed soft tissue trauma (CSTT) accompanied with
bone fractures cost Australians around $500 million per
year for medical services [1]. CSTT usually includes
damage to muscle, blood vessels and nerves. This
causes excessive long term swelling, significant pain,
discomfort and movement deficiencies, which
ultimately leads to a significant socio-economic burden
(Fig. 1). There is evidence that microvasculature
damage can cause tissue loss and ultimately delays the
CSTT healing process [2]. However, a detailed
investigation of the CSTT effect on the
microvasculature (e.g. morphological parameters) has
not been conducted.
The impact device was characterised for a reproducible
CSTT. The impact speed calculated from a high speed
camera (5.3 ± 0.009 m/s) was slightly lower than that
obtained from analytical calculation (5.7 m/s). A protocol
was developed to find the best ratio for the contrast
agent solution (Figure 4) along with the set up for
perfusing the contrast agent through the
microvasculature (Figure 3). The microCT-based
analysis will be used to compare the injured vasculature
with non-injured control limb and analysed for any
changes of blood vessel density, volume, and average
diameter reduction values as a result of CSTT
(Figure 5).
An impact device has been developed and characterised
(Figure 2), which allows for creating a standardised and
reproducible CSTT to the right thigh (biceps femoris) of
anaesthetised rats [4]. After euthanizing the animals at 6
hours, 24 hours, 3 and 7 days after trauma, the
vasculature is perfused (Fig. 3) with a radio-opaque
contrast agent using an infusion pump (Fig. 3). Both
hind-limbs are dissected, and then the injured and
contra-lateral control limbs are imaged using a microCT
scanner to evaluate the morphological changes of the
microvasculature (e.g. vessel density, average vessel
diameter, spacing, anisotropy, etc) . Histological studies
are then utilised for validation of the results derived
from microCT imaging.
1. C. Mathers et al, Health system costs of injury, poisoning and
musculoskeletal disorders in Australia 1993-94, A.I.o.H.a.W. (AIHW), Editor
1999, Australia's national agency for health and welfare statistics and
information: Canberra.
2. F. Tull et al, Soft tissue injury associated with closed fractures: evaluation
and management. Am Acad Orthop Surg, 2003. 11(6): p. 431-438.
3. BodyQuirks Massage Therapy Studio. Available from:
http://www.bodyquirks.com/page/7/
4. L. Claes et al., Moderate Soft Tissue Trauma Delays New Bone Formation
Only in the Early Phase of Fracture Healing. Journal of Orthopaedic
Research, 2006: p. 1178-1185.
5. C. L. Duvall et al, Quantitative microcomputed tomography analysis of
collateral vessel development after ischemic injury Physiol Heart Circ
physiol. 2004. 287: p. 302-310.
An experimental model for studying CSTT in rats has
been developed and characterised. Using the micro CT
visualisation, we expect to determine the impact of
CSTT on the microvasculature and its recovery. A better
understanding of CSTT and its impact on the
microvasculature will establish a fundamental basis for
the quantitative assessment and monitoring of CSTT,
which will ultimately optimise the clinical treatment.
INTRODUCTION
5
Fig.
2
MATERIAL AND METHODS
RESULTS
CONCLUSION
BIBLIOGRAPHY
ACKNOWLEDGEMENT
This project is supported by an IHBI MCR grant awarded
to Dr. Steck.
Figure 2: The set up for characterising the impact velocity with a
high speed camera, a laptop, the impact device and an LED light.
The impactor is dropped from a height of 1.665 m along a guiding
rod. High speed movies were captured from the impact area,
where a frame-by-frame analysis of the impactor position allowed
for the calculation of the impact velocity using a regression
analysis performed in Microsoft Excel software.
Figure 5: A representative 3D reconstruction from a microCT
scan of the entire rat hindlimb microvasculature (from [5]), as we
expect them to be obtained in our experiments. In this ischemia
model the left main artery was ligated, leading to a change in the
microvasculature in the left limb, when compared to the right,
untreated control limb. In contrast, in our model the changes to
the microvasculature will be caused by the CSTT. In this image,
the vessel diameter was colour coded between 0 µm (blue) and
396 µm (red) and mapped to the 3D image surface.
Figure 3: A schematic diagram of the set up for the animal
perfusion using a contrast agent solution. Immediately after
sacrifice, the animal is first perfused with saline to clear the
vasculature, and then with a gelatine based contrast agent
solution.
Figure 4: A cross section from a micro CT scan for five different
concentrations (by volumes) of omnipaque contrast agent in a
gelatine solution. This image illustrates that as the concentration
of omnipaque increases from 0% to 40%, this results in a higher
contrast. This test was conducted in vitro to determine the best
ratio of contrast agent solution for an optimum microvasculature
visualisation. A concentration of 40% was identified to lead to the
best differentiation between microvasculature and bone structure.
Figure1: A majority of CSTTs are caused by sports injuries or road
trauma (A). An ankle injury accompanied by a severe CSTT,
causing swelling and a haematoma (B) [3]
A
B
Ligated artery Control artery
Adapted from Duvall et al, 2004
Contact: Zohreh Barani Lonbani, Institute of Health and Biomedical
Innovation, 60 Musk Ave, Kelvin Grove, Brisbane, QLD 4059, Australia.
Email: z.baranilonbani@qut.edu.au/ Tel: +617 313 86291
AIMS: This research aims to characterise the changes
to the microvasculature after CSTT and during the
healing thereof in a rat animal model using micro-CT
imaging. This will provide a framework for the future
development of clinical and non-invasive means for the
quantitative assessment and monitoring of CSTT.