Knotting of a Perineural Catheter Inserted with Ultrasonography

Objectives: Increasingly, ultrasonography is being used to insert perineural catheters. We report the case of a knotted and retained interscalene catheter that required surgical extraction. Case report: An interscalene catheter was inserted to provide postoperative analgesia in a patient undergoing surgical repair of a proximal humeral fracture. Using ultrasound guidance, the needle tip was advanced in real time next the brachial plexus. Under direct vision, a bolus of local anaesthetic agents was injected and found to surround the plexic roots and trunks. Subsequently, a perineural catheter was inserted blindly past the needle tip. Postoperatively, removal of the catheter (at 24 hours) yielded unexpected resistance. An X-ray of the neck revealed the presence of a knot. The catheter was successfully removed with a surgical incision. The patient suffered no neurological sequelae. Conclusion: In order to maximise the benefits of ultrasound guidance for perineural catheter insertion, the operator should ensure that all steps (needle insertion, local anaesthetic injection and catheter advancement) be carried out under direct vision.