[Myelography, CT scan, electromyography and neurologic examination in the diagnosis of herniated lumbar disk].

The research was carried out at the Clinical Hospital Osijek during a three-year period. Sixty-nine patients (34 men and 35 women) with the diagnosis of lumbar slipped disc who underwent surgery were followed up. The main inclusion criterion was the surgical finding of hernia. The aim of the study was to obtain a clearer insight into the values of the myelography and CT scan by observing a sufficiently large number of patients with surgically verified hernia of lumbar disc. The characteristics of neurological and EMG findings were surveyed, as well. Thirty-one patients were at the age of 40-49 years and 21 were at 30-39 years of age. Only 5 hernias were at the level L3L4, 28 at the level L4L5, and 46 at the level L5S1. Sensitivity, specificity and overall accuracy of the observed parameters were estimated for 41 leftwards and 30 rightwards located hernias. Myelographic finding, regardless of the observed level of slipped disc, showed excellent sensitivity, specificity and accuracy of diagnosis. CT finding was slightly less sensitive at the level L4L5, it was 0.93, and specific at the level L5S1, amounting to 0.90. Its accuracy was not substantially lower than that of myelography. The pathological EMG was 0.88 sensitive, 0.83 specific and 0.84 accurate. The accuracy was excellent at the level L3L4, it was 0.96, but only very good at the level L5S1, amounting to 0.76. A t-test of linked pairs was used to compare surgical reports and diagnostic findings. There was a great similarity between a CT finding and surgical one in all three levels (t-values 1.00, 0.21 and 0.36). Myeolography was more congruent with the surgical finding in the middle level (t-values 1.65, 0.93 and 1.52). An EMG finding was significantly different from that found by surgery (t-values 1.71, 1.76 and 2.71). The existence of Lasègue's sign for the diagnosis of hernia was 0.93 sensitive, 0.07 specific (remarkably low) and 0.36 accurate. It was particularly inaccurate at the level L3L4, moderately accurate at the level L4L5, and rather accurate at the lowest level L5S1. The weakened Achilles tendon reflex was less sensitive than Lasègue's sign, amounting to 0.80. Its specificity was 0.19 and accuracy 0.40. The highest accuracy was in hernias of the lower two levels L4L5 and L5S1. The existence of weakened sense was 0.91 sensitive, specificity was remarkably low, amounting to 0.08, and accuracy was 0.36. It was most inaccurate at the level L3L4 and slightly better at the levels L4L5 and L5S1. Disturbance of leg movements showed sensitivity of only 0.60, but specificity was 0.39 and accuracy 0.46. It was most precise at the level L4L5. Neurological symptoms and signs were insufficiently sensitive and specific for the diagnosis of lumbar disc hernia. On the basis of these parameters, the level of hernia could not be exactly determined.