NEW YORK (Reuters Health) - Provocative clinical tests -- palpation for nerve thickening and local tenderness, Tinel's test and flexion compression tests - are of little value in diagnosing ulnar neuropathy at the elbow and should not be substituted for electrophysiological studies and neurosonography.
Yet provocative tests are often the basis not just for diagnosis of ulnar neuropathy but also for performing surgery, even though evidence supporting their use is limited.
So say researchers in the Netherlands, whose study appears in the December Journal of Neurology, Neurosurgery and Psychiatry.
Their cohort included 192 patients with numbness and/or paresthesias of the fourth and fifth digits of the hand, and/or weakness or clumsiness of muscles innervated by the ulnar nerve
Lead author Dr. R. Beekman and colleagues at the Atrium Medical Center in Heerlen report that after routine neurological exams and provocative tests, patients underwent electrophysiological and sonographic studies, with ancillary testing when necessary. Fifty-five patients who received diagnoses other than ulnar neuropathy at the elbow were analyzed as controls.
No provocative test or combination of tests was both sensitive and specific for ulnar neuropathy, the authors report. Diagnostic accuracy was 59% for Tinel's test, 55% for the flexion compression test, 46% for nerve tenderness and 45% for ulnar nerve thickening during palpation.
With combinations of two or more tests, any increase in sensitivity was accompanied by substantial loss of specificity. The authors add, "Although the positive predictive value of all four tests was considerable, the negative predictive value was very low."
Furthermore, logistic regression and receiver operating characteristic curves indicated that provocative tests added minimal value to routine clinical examination.
Ultrasonography did add value to electrophysiological tests, Dr. Beekman's group notes. "In this study," they write, "23% of the patients were finally diagnosed with ulnar neuropathy of the elbow by demonstrating focal ulnar nerve thickening at the elbow while more than one-third of these patients had non-localizing electrophysiological abnormalities."
"Provocative tests cannot be used...to make a diagnosis of ulnar neuropathy of the elbow more likely when electrophysiological tests are negative," the researchers maintain.
Otherwise, they say, the possible "result (is) surgery for patients with conditions other than ulnar neuropathy at the elbow."
