Study design: Straight leg raising was recorded before myelography in 77 patients. At myelography, samples of cerebrospinal fluid were drawn and later analyzed for neuropeptides vasoactive intestinal polypeptide and somatostatin.
Objectives: The study sought to examine correlations, if any, between a positive straight leg raising test and cerebrospinal fluid neuropeptide levels.
Methods: The straight leg raising test was recorded for all patients before a myelography examination was performed because of intractable leg pain symptoms. Forty-seven of the patients were men and 30 were women. Cerebrospinal fluid samples were obtained from all patients upon myelography. Levels of the neuropeptides vasoactive intestinal polypeptide and somatostatin were analyzed in a blind manner by radioimmunoassay, using commercially available radioimmunoassay kits.
Results: The results are compatible with previous observations that suggest cerebrospinal neuropeptide levels are altered in conjunction with neural injury or pain syndromes. In the present mixed back pain patient population, which included radicular pain symptoms due to disc herniation and lumbar stenosis, alterations in vasoactive intestinal peptide levels in particular were observed with a positive straight leg raising test.
Conclusions: Nerve root injury, as suggested by a positive straight leg raising test, appears to be neurochemically linked to altered cerebrospinal fluid vasoactive intestinal peptide levels.