Radiofrequency Ablation Within the First Intercoccygeal Disk for Coccygodynia: A Case Report

Interventional procedures for coccydynia (coccygodynia) are limited. This is a case report of long-term improvement following radiofrequency ablation (RFA) within the 1st intercoccygeal disk. Case Presentation: A 44-year-old female presented with a 1year history of coccydynia following a fall. Examination under fluoroscopy localized her pain at the disk between the 1st and 2nd coccygeal vertebrae. Provocation with needle entry reproduced the patient's pain, and the 1st intercoccygeal disk was injected with 40mg of methylprednisolone. This gave the patient excellent relief for about 3weeks. The procedure was repeated at 4weeks, providing with the same response. Decision was then made to proceed with RFA. Her symptoms were reproduced in response to stimulation at 50Hz with 0.9V, and stimulation at 2Hz at 2V did not result in any motor stimulation. RFA was then carried out at 70°C for 80seconds, followed by injection of 20mg of methylprednisolone. The patient's Numeric Rating Scale pain score decreased from 9/10 to 3/10 after the RFA. She had about 70% relief for about 6months. Discussion: There is evidence that intercoccygeal disks can be a source of coccydynia. Immunohistochemistry has shown mechanoreceptors in intercoccygeal disks, and coccygeal discography has been shown to reproduce coccygeal pain. Intercoccygeal disk injection is described as a therapeutic option in the literature. Because various RFA techniques have been successfully used for intervertebral diskogenic pain, the decision was made to attempt RFA at the 1st intercoccygeal disk with resultant significant long-term improvement.