Two stuck epidural catheters

We would like to report two instances in which removal of a 16-G Tuohy needle or threading assist device was not possible over the proximal (non-patient) end of a Portex Epidural Minipack (Smiths Medical International Ltd, Ashford, Kent, UK) catheter, after successful placement of the catheter tip in the epidural space for labour analgesia. In the first instance, the threading assist device got stuck at the proximal end of the catheter (Fig. 2). Traction was applied, stretching the catheter, but without success. Sterile scissors were used to cut the catheter distal to the withdrawn Tuohy needle/threading assist device. The epidural catheter was left in situ, inserted into the catheter connector and used successfully to provide labour analgesia. In the second instance, the catheter was inserted without using a threading assist device, but removal of the 16-G Tuohy needle tip was not possible over the proximal end of the catheter. Again, traction was unsuccessful and sterile scissors had to be used to cut the catheter distal to the needle, but the catheter tip remained in situ and was used to successfully provide labour analgesia. Case reports involving epidural catheter-related problems are common, but normally involve the distal (patient) end of the catheter. Chao and Seevanayagam reported an aneurysmal defect 30 cm from the distal tip of a catheter, preventing Tuohy needle withdrawal 1. Williams and Howell reported a case in which the epidural catheter got stuck in the Tuohy needle on withdrawal, thought to be caused by a localised increase in the outer diameter of the catheter during extrusion in the manufacturing process 2, but were reassured by the manufacturers that new quality control measures during manufacture ensured catheter passage through orifices smaller than the internal diameter of a 16-G Tuohy needle. Despite such reassurances, we think that this is what occurred in both the cases presented, namely that a fault in the extrusion process during catheter manufacture led to an increase in the external diameter of the catheter. We reported both cases to the manufacturer six months ago, but are yet to receive any convincing explanation from them. The Medicines and Healthcare products Regulatory Agency have also been informed. Anaesthetists are familiar with flushing epidural catheters before insertion to check their patency, but we would reinforce the necessity of checking complete passage of the catheter through both the Tuohy needle and the threading assist device before any attempt at catheter insertion.