Ultrasound-Assisted Mental Nerve Block and Pulsed Radiofrequency Treatment for Intractable Postherpetic Neuralgia: Three Case Studies
A 45-year-old man visited our pain clinic with the chief complaint of right mandibular area pain. The patient had been diagnosed with facial herpes zoster in the right V3 area 9 months previously. The right facial pain had continued for 9 months despite medical treatment. During this period, 300 mg pregabalin, 10 mg amitriptyline, and three 37.5 mg tramadol/375 mg acetaminophen combination tablets were administrated per os daily but had little effect. He had paroxysmal, sharp, and shooting pain in the right mandibular area. The pain was aggravated by touching the right mandibular area, and palpation over the right mental foramen reproduced the pain. Pain severity was 10/10 on a VAS.\nHence, we started pain intervention for PHN in the left V3 area. We initially blocked the right mental nerve under US with a 10-12 MHz linear transducer using a mixture of 2 ml 2% mepivacaine and 20 mg triamcinolone. This procedure decreased the pain immediately, and pain severity was 0-1/10 on a VAS. One month after this intervention, his pain relief was >90%. Because relief was maintained continuously throughout the 2, 4, 6, and 12 months follow-ups after US-assisted mental nerve block, no additional treatment including medication was provided.