Removal of a knotted stimulating femoral nerve catheter using a saline bolus injection

Abstract

Stimulating peripheral nerve catheters have become increasingly popular as part of postoperative multimodal analgesia for total knee arthroplasty. We describe a case of a successful nonsurgical removal of a knotted stimulating femoral nerve catheter after saline expansion of the catheter pocket at the bedside. A 65-year-old female underwent total knee arthroplasty under combined spinal epidural anesthesia. Postoperatively, a stimulating femoral nerve catheter was placed without complication. The catheter was threaded 12 cm past the needle tip with minimal resistance. Function of the catheter was verified by loss of pinprick sensation in the femoral nerve distribution and excellent analgesic efficacy was achieved. The first attempt at catheter removal was unsuccessful. Thigh flexion and rotation also failed to facilitate catheter removal. The catheter was then left to continuous tension for 6 hours, but further attempts at removal remained unsuccessful. Under ultrasound visualization, 10 mL of saline was injected through the catheter with moderate resistance and without patient discomfort, after which the catheter was removed using minimal tension. The catheter was intact but had a single knot at the distal end of the catheter. We present a rare case of a knotted stimulating catheter in which the use of a saline bolus to dilate the catheter pocket proved to be successful after other simple methods of catheter removal had failed. Given the simple nature of this technique, it can be attempted at the bedside before more invasive procedures are planned.