Ultrasound-guided Pulsed Radiofrequency of the Third Occipital Nerve
The first patient is a 39-year-old male who complained of posterior neck pain and occipital headache on the right side after a rear-end collision, which occurred one month ago. At the time of the accident, he suffered from radiating pain in the right arm, but the radiating symptom subsided by the time of his first visit to the clinic. There were no specific findings on cervical MRI. Diagnostic block on the right TON was performed with 0.9 ml of 1% lidocaine. Two weeks later, the block was done with 0.9 ml of 0.25% bupivacaine. There were 50% pain reductions after each block. After confirmation of positive responses, the patient underwent pulsed radiofrequency of the right third occipital nerve under fluoroscopic control. A 22-gauge, 10-cm-long, 10-mm active tip RFK needle (Radionics Inc., Burlington, MA, USA) was used. Symptom subsided, but 8 months later, the same symptom on the right occipital area and posterior neck pain recurred. Another diagnostic block was performed under ultrasound control, and pain relief was achieved. With pain relief, we decided to perform ultrasound guided pulsed radiofrequency of TON.\nThe patient was in the left lateral decubitus position. We first located 5-12 MHz linear ultrasound transducer (SonoSite Inc., Washington, USA) on the mastoid process, longitudinally. Moving the transducer more caudally, we found C2-3 zygapophygeal joint. TON was founded as a hypoechoic oval shape encircled by a hyperechoic halo at C2-3 zygapophygeal joint line (). C3 deep medial branch nerve was also founded at the middle of the articular pillar of C3 (). The RFK needle used in previous pulsed radiofrequency was inserted to TON craniocaudally, using an in-plane approach (). Response to sensory stimulation was checked at 50 Hz, 0.5 V, and pulsed radiofrequency was conducted twice for 120 seconds on 42℃. In order to confirm the exact location, we cross checked the image with fluoroscopic view (). Same manner of approach was used for C3 deep medial branch, and we terminated the procedure. Patient's numerical rating scale (NRS) decreased from 7 to 2. Four months after the procedure, patient's pain is maintained at NRS 2, and he is on a regular departmental outpatient follow up.