Smith MD, Bressler EL, Lonstein JE, Winter R, Pinto MR, Denis F.
Deep venous thrombosis and pulmonary embolism after major reconstructive
operations on the spine. A prospective analysis of three hundred and seventeen
patients.
J Bone Joint Surg Am 1994 Jul;76(7):980-5

Minnesota Spine Center, Minneapolis 55454.

We performed a prospective study of 317 patients in order to determine the
prevalence of deep venous thrombosis after reconstructive operations on the
spine; 126 of the patients were examined with duplex ultrasound assessments of
the lower extremities to ensure that no asymptomatic thrombi were being missed.
Thigh-high stockings and sequential pneumatic compression of the lower
extremities were used, in all patients, for prophylaxis against venous
thrombosis. No antiplatelet agents or anticoagulant medications were
administered. There was no evidence of thrombosis on any of the duplex ultrasound
studies. Subsequently, venous thrombosis developed and was treated successfully
in one of the 126 tested patients and in one of the 191 untested patients, and a
fatal pulmonary embolus developed in one of the untested patients. The over-all
clinical prevalence of thrombotic complications was 0.9 per cent (three
complications in 317 patients). All three of the patients who had clinical
evidence of thrombosis had had an anterior lumbar procedure because of a
degenerative disorder or trauma; however, we could not prove that this approach
or these diagnoses were significant risk factors for thrombosis (p < 0.05). While
it is possible that some thrombi may have escaped both clinical and ultrasonic
detection, such thrombi apparently were not enough of a danger to warrant the use
of intensive prophylactic procedures that are associated with more risk. On the
basis of this prospective study, therefore, we think that routine screening for
the detection of asymptomatic thrombosis in patients who have had a procedure on
the spine is unwarranted.