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A Novel Indication for a Femoral Nerve Catheter
Flap surgery is a technique in plastic and reconstructive surgery that involves the re-implantation of autologous tissue to a recipient site with its blood supply intact (1). One of the fundamental anesthetic goals for flap surgery is maximizing blood flow to the graft implantation site to assist in overall graft success. This case report illustrates the utilization of an emergent femoral nerve catheter placed in a patient under general anesthesia as a salvage technique to augment free flap blood flow and improve overall surgical success.
The patient is a 29 year old male who sustained poly-traumatic injuries following a motorcycle accident. He was transferred to the University of Colorado for left lower extremity salvage/restoration consultation by our orthopedic and plastic surgery services. His past medical history was pertinent for chronic pain syndrome, taking methadone 80mg daily at the time of the accident.
To treat his open fractures (distal tibia/fibula) and degloving injury, he underwent a right vastus lateralis free muscle flap to provide soft tissue coverage of his left lower extremity. The surgical team performed an uncomplicated harvest of a 10cm X 20cm right vastus lateralis free muscle flap with successful re-anastomosis of the attached descending branch of the lateral circumflex femoral vessels to the peroneal artery stump. As surgical closure was nearly completed, there was momentary loss of arterial and venous signals, thought to be secondary to vasospasm. After discussion with the attending surgeon and anesthesiologist, we decided to proceed with an emergent placement of femoral nerve catheter. After a perineural injection of local anesthetic (20ml of Ropivicaine 0.5%) the patient had near immediate recovery of Doppler signals in the free flap. A continuous infusion of Ropivicaine 0.2% at a rate of 6-12ml/h was maintained for 19 days postoperatively. At a three month follow-up appointment, the free flap remained healthy and intact.
Peripheral nerve catheters are overwhelmingly performed for post-surgical analgesia. Nonetheless, there have been a multitude of case reports illustrating alternative indications for continuous peripheral nerve catheters (Table 1) (2). This case reports suggests that free flap surgical procedures are yet another indication for nerve catheters.
The primary benefit of regional anesthesia for this type of surgery is the induced sympathectomy with resultant increased blood flow. Multiple studies have validated both venous and arterial dilation after nerve blocks. One such study was able to quantify a 1.9X increase in arterial blood flow after an axillary nerve block (3). Additional benefits include reduced incidence of deep vein thrombosis, maintenance of normothermia, and superior analgesia with decreased stress response (4, 5).
This case report illustrates a clear benefit of regional anesthesia for free flap surgery and suggests why it should be considered as part of a balanced anesthetic in appropriate cases.