The recurrence of pain following operation for herniated lumbar disc: fresh herniation or extradural scar tissue?

The clinical findings, the appearance of the myelogram and the findings at re-operation are described in 34 patients who had persistent or recurrent pain following operation for removal of a herniated lumbar disc. An attempt was made to distinguish before re-operation whether the residue symptoms were due to recurrence of, or a fresh disc herniation, or to extradural scarring. Persistence of pain after the initial operation or the time interval before pain re-appeared did not help to distinguish the causative pathology. A recurrent disc herniation was found if a different disc was involved, but was else best distinguished by myelographic demonstration of a short indentation in the contrast column at the level of a disc or a short root sleeve with a thickened associated nerve root. An absence of indentation in the column suggested extradural scarring. At re-operation disc herniation and extradural scarring without herniation were found in approximately equal numbers of patients.