Relevance of epidurography and epidural adhesiolysis in chronic failed back surgery patients

Pain treatment in the chronic failed back surgery patient remains problematic. Defining the pathogenesis of the pain could be helpful in treatment. The assumption that epidural fibrosis and adhesions might play an important role in the origin of the pain is verified.

We investigated 34 patients in whom peridural fibrosis was suspected. An epidural catheter was inserted via the sacral hiatus. Injections of contrast dye, local anesthetic, corticosteroid, and hypertonic NaCl 10% were carried out daily for 3 days. Spread of the contrast dye in the epidural space was evaluated after 10 and 20 ml injection volume.

Subjects were patients in a pain clinic of a university hospital in Belgium.

Chronic pain patients with failed back surgery syndrome were examined. Nerve pathology was demonstrated and epidural fibrosis suspected or proved with magnetic resonance imaging (MRI) examination.

Improvement in the contrast filling defects of the epidural space were noticed during treatment and correlated with pain improvement.

Filling defects were noted in 30 of the 34 patients investigated. After the third day an objective improvement of contrast spread was documented in 14 patients. In seven patients improvement in pain occurred for only a very limited period (1 month). Statistical analysis (chi square analysis) could not demonstrate that improvement of contrast spread was correlated with better pain behavior. In 16 patients no improvement in contrast spread could be visualized. Pain improvement occurred in only four patients and for a limited period of 1 month. Long-term results are even worse.

Epidurography might confirm epidural filling defects for contrast dye in the patients with epidural fibrosis. A better contrast dye spread, assuming scar lysis, does not guarantee a sustained pain relief. A more direct visualization of the resulting functional changes after adhesiolysis as with epiduroscopy might be useful.