Epidural fibrosis after permanent catheter insertion and infusion.

Forty-six permanent epidural catheters and life-port units were implanted in 43 patients with severe, recurrent low back pain who had been considered not to be candidates for surgical intervention and in whom other therapeutic modalities had failed. Eight cases developed epidural fibrosis (EF). For analgesia, patients received either infusions with preservative-free solutions of fentanyl and bupivacaine or daily boluses of morphine and bupivacaine. Catheters remained from 75 days to 433 days. Signs of EF appeared from 21 days to 320 days after implantation. Pain at injection or resistance to injection were initial manifestations of EF, followed by poor, and eventually, nil analgesic effect. The epidural catheters were made of either polyamide, silicone, or polyurethane. Epidurograms revealed encapsulation, narrowing, and loculation of epidural space with gradually reduced spread of the contrast material. The occurrence of EF limits the permanency of implanted epidural catheters. The infusate does not cause this complication, which appears to be a foreign body reaction due to the presence of the catheter in the epidural space.