Knot Formation at Removal of an Epidural Catheter Placed Against Insertion Resistance Encountered at the Entrance of the Epidural Space

Knotting of an epidural catheter occurs very rarely with an estimated incidence of 0.0015%. We present a case of an epidural catheter knot formed at removal of an epidural catheter following a forceful insertion of the catheter against resistance met at the entrance of the epidural space during threading of the catheter through Tuohy needle placed uneventfully in a 65 year-old male patient undergoing epidural anesthesia. During removal of the epidural catheter, significant resistance was encountered on traction and it was found that approximately 1.5 ㎝ portion of the catheter had been retained within the patient's subcutaneous tissue. Firm traction was employed to withdraw the catheter against the resistance. The catheter was pulled out uneventfully from the patient. A knot estimated to be formed during removal of the catheter was observed at 0.6 ㎝ proximal to the catheter tip. No complications and side effects were noted until the patient's discharge.