CHAPTER 16
VENOUS THROMBOSIS AND PULMONARY
EMBOLISM
Incidence and mechanism
These complications following surgical procedures and injuries have been the subject
of many publications in non-paraplegic patients, and their incidence is still relatively
high. Murley (1950) studying 1763 surgical cases found the overall incidence of fatal
pulmonary embolism to be i-n per cent and the incidence of non-fatal embolism to be
5 to 6 times greater.
In considering the mechanism, there is general agreement that the most important
single factor is the sluggishness of the venous circulation and weakening or absent calf
muscle pump resulting in venous stasis (Dott & Cockett, 1956). Amongst other factors
promoting deep venous thrombosis, age above 40 certainly plays an important part.
Deep venous thrombosis is not uncommon in paraplegics and tetraplegics. It is
obvious that the flaccidity of the skeletal muscles and the paralytic vasodilatation as a
result of the vasoconstrictor paralysis in the acute and early stages have their adverse
effect on the blood flow (Wakin
et at.,
1948). Although there is some tone in the smooth
muscles of the veins, this cannot compensate for the absence of the muscle pump in the
flaccid state of the skeletal muscles. Moreover, pressure on the calves against the bed
facilitates the development of stasis and venous thrombosis.
Phillips (1963) investigated clinically and radiologically 25 paraplegics, i.e. 50
limbs—to ascertain the incidence of deep venous thrombosis. The average age of the
patients was 39-5 years. With one exception, all cases were traumatic, 17 were flaccid, 3
flaccid with spasms, 5 with partial motor recovery. He found that in 33 of 50 limbs the
normal soleal sign was absent due to absence of tone in the soleus muscle. Normally the
contrast filling of the distal part of the posterior tibial veins may be poor or absent
because the normal soleus muscle at its fibrous origin from the soleal line compresses the
dye from the vein (positive soleus sign). Two of 50 limbs (14 per cent) showed evidence
of previous deep venous thrombosis. There was a higher incidence of thrombosis in
the left leg.
In 1963 the writer reported 30 deaths out of 396 patients (7-6 per cent) admitted
between 1951 and 1963 within the first 15 days of injury. Nine of the 30 deaths were due
to pulmonary embolism (4 cervicals) and 2 (cervicals) due to coronary thrombosis and
heart failure (Guttmann, 1963). Walsh & Tribe (1965) reported an overall incidence
of venous thrombosis and pulmonary embolism of 13-2 per cent out of 500 paraplegics
and tetraplegics admitted to Stoke Mandeville within 14 days of injury, of which 3 per
cent were fatal. There was a higher incidence in complete lesions (16-5 per cent) as
compared with incomplete lesions (9 per cent) and complete thoracic lesions showed a
particularly high incidence (19-1 per cent). Fatal embolism occurred at any time from 4 to
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