Visualization of a looped and knotted epidural catheter with a guidewire

To describe the management of a looped and knotted epidural catheter after analgesia for labour and delivery. Obstetrical epidural pain relief was provided for a 37-yr old woman in early labour. A 20-gauge Portex catheter was inserted at the L2-L3 interspace. Six centimetres of catheter was left in the epidural space. After vaginal delivery the catheter could not be removed. The catheter was left in situ for 24 hr. Repeated attempts at removal were again unsuccessful. The epidural catheter was not visible with fluoroscopy and it was impossible to inject radiopaque dye into the catheter. However, we successfully advanced a 0.016 inch guidewire through the epidural catheter and radiologically demonstrated a knot and part of a loop. The catheter was removed by an orthopedic surgeon using blunt dissection under local anesthetic from the soft tissue just lateral to the interspinous ligament. A knot can be a rare cause of a trapped epidural catheter. A suggested approach to the trapped lumbar epidural catheter: 1) Gentle traction on the catheter with the patient in various positions and in various degrees of lumbar flexion. 2) Test for catheter patency by injecting sterile, preservative-free, normal saline through the catheter. 3) Radiological imaging to determine if a knot is present and to determine its location, using radiopaque contrast for patent catheters or a guidewire for occluded catheters. 4) The approach to definitive management is based on the position of the knot. This can range from excision under local anesthetic to consultation with a surgical specialty for more invasive retrieval.