Ultrasound-guided superficial fibular nerve block in the emergency department for refractory cancer-related lower extremity pain

Background

Ultrasound-guided nerve blocks have been increasingly used in the emergency department (ED) to provide effective regional analgesia without relying on the use of systemic medications, which given in high quantities may cause respiratory depression. Ultrasound-guided nerve blocks of the superficial fibular nerve have been relatively understudied in the context of ED utilization.

Case report

We report the case of a 65-year-old woman with a history of acute lymphoblastic leukemia (ALL) on lifelong non-cytotoxic chemotherapy and sarcoma who presented with a chief complaint of right lower extremity pain for one week after minor trauma. She reported severe pain and was unable to bear weight. Her workup was negative for fracture, thrombus, compartment syndrome, and limb ischemia. Pain relief was not achieved even after the utilization of several doses of parenteral analgesics. After 12 hours in the ED, the patient was treated with an ultrasound-guided superficial fibular nerve block. Within one hour of treatment, she was able to ambulate and was discharged. During an oncology follow-up visit, she was found to have a recurrence of malignancy in her area of pain based on an outpatient bone scan and MRI. This case report demonstrates the successful utilization of a superficial fibular nerve block for refractory cancer-related pain.

Why should an emergency physician be aware of this?

Cancer-related refractory pain is one of the most difficult conditions to treat in the emergency department. Patients requiring multiple high doses of opioids and sedatives are at risk for airway compromise. Refractory pain related to cancer can lead to extended ED stays or hospital admission. This case study highlights the use of a superficial fibular nerve block for refractory cancer-related pain in the ED and details the technique for performing the procedure.