Minimally invasive retrieval of knotted nonstimulating peripheral nerve catheters

Objective: Continuous peripheral nerve blockade is rapidly becoming the technique of choice for the management of postoperative orthopedic pain. However, the insertion of perineural catheters may be associated with complications, including catheter kinking and knotting. A knotted catheter may be difficult or impossible to remove at the patient bedside, requiring Surgical excision under general anesthesia. We describe a previously unreported minimally invasive technique of retrieving knotted peripheral nerve catheters and avoiding the need for surgical intervention. Although the described technique has been used by interventional radiologists for the removal of knotted intravascular devices, it has not been previously described for the retrieval of knotted perineural catheters. Brief Report: The Mayo Clinic Acute Pain Service database was queried and patients identified with knotted peripheral nerve catheters during the 3-year period from January 2003 to January 2006. The medical records of all identified patients were retrospectively reviewed and details of catheter placement including catheter type and location, size (gauge), ease ofplacement, distance threaded, and duration of use recorded. During the study period, 5,964 nonstimulating peripheral nerve catheters were placed. Of these, 8 (0.13%) patients experienced catheter knotting resulting in difficult or impossible catheter removal at the bedside. Seven (88%) of the 8 catheters were successfully removed by using a minimally invasive technique of catheter retrieval using guided fluoroscopy. The remaining catheter was removed at the bedside with patient repositioning. Conclusions: The knotting of peripheral nerve catheters is a relatively uncommon phenomenon, occurring in only 0.13% of patients. However, because the use of perineural catheters has increased within anesthesia practice, clinicians may begin to encounter these complications with greater frequency. Practitioners should be aware of surgical alternatives, including guided-fluoroscopic techniques, when simple catheter traction or tension proves unsuccessful at the patient bedside.