Biomedical Engineering Reference
In-Depth Information
Chapter 6
Long Bones
A middle-aged adventurous man was some years ago on a 10-day motorbike trip
through Peru. On his way back from the jungle Madre de Dios to Cuzco, our expe-
rienced motorbiker did not see a hole in the jungle track by the dirt blown up by his
fellow companions. His vehicle landed upside down off the road while smashing his
driver ungently on Peruvian soil
end of the Peruvian trip. Half an hour later an aid
station, oh wonder, could send a doctor. The supracondylar humerus fracture was
immobilized
avec les moyens du bord
: cardboard and belts splinted the fracture in
extension. The safety pin on the radiograph is an undeniable witness of the emer-
gency treatment. Hours later the patient arrived in Cuzco on board of an improvised
ambulance with paracetamol as the only pain killer. An upper arm plaster immo-
bilized the elbow in extension (this time anesthetized!) allowing the transport of
the patient to the academic hospital of the university of Ghent (Belgium). The bits
and pieces were adequately hold together by locking plates and screws as shown on
the radiographs of Fig.
6.1
. The issue was successful and three days later a pleased
patient left the hospital. The case was told us by Prof. R.Verdonk (Department of
Physical Medicine and Orthopedic Surgery, Ghent University, Belgium).
The first aid in the case of the high impact fracture was offered by splinting using
simple materials as cardboard and belts. What is a more advanced materials toolbox
offering us for temporary or permanent exo- or endo-support in such cases?
:::
6.1
Plaster of Paris
The splinting of broken legs by a
composite
of bandage and the hemihydrate
of calcium sulfate has been invented by the Dutchman Mathijsen in 1851. The
hemihydrate is formed by heating the mineral gypsum to 150
ı
C:
CaSO
4
:
1
2
2
CaSO
4
:2
H
2
O
• 2
H
2
O
C3
H
2
O
%
(6.1)
In contact with water, the reaction is reversed and the impregnated bandage hardens
by hydration to gypsum. A large deposit of gypsum was exploited for the building
industry near Montmartre (Paris), explaining the name
platre de Paris
. But its use
