Diagnostic Accuracy of the Clinical Examination in Identifying the Level of Herniation in Patients with Sciatica

Study Design. Cross sectional Objective. To investigate the ability of the neurological examination to identify the specific level of a disc herniation in patients with sciatica and confirmed disc herniation. Summary of Background Data. Tests included in a neurological examination theoretically provide accurate diagnostic information about the level of the herniated disc. However, there is currently very little evidence about the diagnostic accuracy of individual tests or combinations of tests. Methods. The study included 283 patients with sciatica and confirmed disc herniation from a previous randomized controlled trial. The reference test for the current study was the MRI scan, reported for level of disc herniation. Index tests investigated were a neurologist's overall impression of the level of disc herniation, individual neurological tests (e. g., sensation testing) and multiple test findings (i.e., the number of positive tests). The index tests were performed blinded to the MRI results. The diagnostic accuracy of the index tests in predicting herniations at the lower three lumbar discs was investigated using area under the curve (AUC), sensitivity and specificity. Results. None of the individual neurological tests from the clinical examination were highly accurate for identifying the level of disc herniation (AUC > 0.75). The outcome of multiple test findings was slightly more accurate but did not produce high sensitivity and specificity. The dermatomal pain location was generally the most informative individual neurological test. The overall suspected level of disc herniation rated by the neurologist after a full examination of the patient was more accurate than individual tests. At L4/5 and L5/S1 herniations the AUC for neurologist ratings was 0.79 and 0.80 respectively. Conclusion. The current study did not find evidence to support the accuracy of individual tests from the neurological examination in identifying the level of disc herniation demonstrated on MRI. A neurologist's overall impression was moderately accurate in identifying the level of disc herniation.