Ultrasound-guided Percutaneous Peripheral Nerve Stimulation for the Treatment of Complex Regional Pain Syndrome Type 1 Following a Crush Injury to the Fifth Digit: A Rare Case Report.

This case report presents an application of percutaneous peripheral nerve stimulation to the left ulnar nerve to treat a patient with complex regional pain syndrome type 1 following a crush injury to the left fifth digit. Conventional treatment had failed to ameliorate the patient's condition. After a successful seven-day trial with an ulnar peripheral nerve catheter, which followed an unsuccessful capsulectomy of the metacarpophalangeal and proximal interphalangeal joints of the left fifth digit with tenolysis of the flexor tendons, the patient underwent an uneventful implantation of a percutaneous peripheral nerve stimulator parallel with the trajectory of the left ulnar nerve just distal to the ulnar tunnel. Two weeks after implantation of the percutaneous peripheral nerve stimulator, the patient reported a reduction in the pain, with the intensity score coming down from 7 out of 10 to 0-1 out of 10 on the numeric rating scale (NRS). The patient was able to initiate pain-free active motion of her left fifth digit. At the 3-month follow-up consultation, the patient reported maintenance of the reduction of pain in her left upper extremity with the implanted percutaneous peripheral nerve stimulator, as well as improved performance in her daily activities. Despite the success achieved in this particular case, further clinical series involving larger numbers of patients are warranted in order to assess the definitive role of percutaneous peripheral nerve stimulation for the treatment of neuropathic pain of the upper and lower extremities, which has been previously unresponsive to medical and/or surgical treatment.