Knotted epidural catheter: the role of determining a catheter’s ultimate tensile strength before pulling on it. A case report and literature review

Abstract

Knotting is a well-known but rare complication of the use of epidural catheters. We report the case of a knotted catheter successfully removed by simple traction, after determining its ultimate tensile strength. We reviewed the case reports published since 1979. We assessed the prevalence of this complication, the impact of placement technique on a knot’s occurrence, the value of the different imaging modalities, and the one of various techniques used for catheter removal. A knotted catheter can often be removed intact with steady and gentle traction. Before pulling on an entrapped catheter and to avoid breakage, it may be useful to assess its ultimate tensile strength on its free extremity or another identical catheter. Limiting the length of a catheter threaded in the epidural space during its insertion seems to be the best way to avoid knots.