Blood clots in vessels surrounding symptomatic nerve roots in disc herniation patients: a pilot study

Mechanical compression and biochemical influences, e.g. by various inflammatory cells and mediators, have been suggested to be involved in the pathophysiology of sciatica. In addition, it has been suggested, but so far not clearly demonstrated, that blood pooling in the venous blood vessels surrounding nerve roots may contribute to impaired nerve root function and sciatica. There is also more direct evidence from studies on an animal model that nucleus pulposus (NP) tissue may induce blood vessel thrombosis. In the present study, a specific monoclonal antibody to platelet membrane glycoprotein complex GPIIb-IIIa was used for direct visualization of blood clots in tissue samples removed from the vicinity of symptomatic nerve roots in 20 disc herniation (DH) patients. For 12 patients, the DH was primary, for 7 patients recurrent and for 1 patient the index operation was for root canal stenosis following a DH operation 3 months earlier. Blood clots immunoreactive to GPIIb-IIIa were observed in small blood vessels in 11/20 tissue samples (55%), in 5/12 patients (42%) with primary DH and in 5/7 patients (71%) with recurrent DH. The presence or absence of GPIIb-IIIa complex immunoreactivity did not show a statistically significant relationship with pain duration, DH type (primary or recurrent), gender or straight leg raising (SLR). Thus, though immunohistochemically demonstrable, the observed periradicular blood clots could not be established to have a clinical role in sciatica in this pilot study.