The crossed straight leg raising test: a diagnostic sign of herniated disc.

Increased sciatica on raising the opposite or "well" leg, the crossed straight leg raising (XSLR) sign, is associated with a herniated lumbar disc in 97% of patients. Although XSLR predicts poor response to conservative management, the results of laminectomy are usually good, with 91% of patients returning to work. Myelography is unnecessary for the diagnosis of disc herniation in patients with XSLR. It is possible for patients with this sign to have a normal myelogram, but 90% of them will prove nevertheless to have a herniated disc.