Diagnostic lumbar nerve root block.

Lumbar nerve root anesthesia using a local anesthetic was performed in 100 cases of sciatica. The neurological state before and after nerve block was recorded and also the degree of pain alleviation caused by the block. Three indications for the block were used in the study: unilateral sciatic pain and normal findings on myelography and/or CT or MR (n = 51), minor myelographic findings that possibly but not necessarily explained the patient's symptom (n = 40), and multiple pathological findings on myelography (n = 9). In 87% of the patients, the nerve block inflicted temporary sensory and/or motor disturbance within the dermatome anesthesized. In total, 51% experienced total, 31 partial, and 18 no pain relief after injection. No side effects of the procedure were noted. Patients with pain alleviation after anesthesia were offered an operative nerve root decompression and short-term results of this decompression seem to be comparable to conventional disc surgery. Anesthetizing the lumbar nerve root outside the intervertebral foramen may be considered in the preoperative evaluation of patients with sciatic pain and minor or no radiographic findings.