Chronic coccydynia is a condition characterized by persistent pain in the coccyx region that significantly affects daily activities and quality of life. When conservative treatments fail, interventional pain procedures such as radiofrequency ablation may be considered.

This single-center, prospective, randomized study compared two radiofrequency ablation techniques used in the treatment of chronic coccydynia: fluoroscopy-guided ganglion impar radiofrequency ablation and ultrasound-guided coccygeal nerve radiofrequency ablation. Adult patients with chronic coccydynia who did not respond to medical treatment were randomly assigned to receive one of these two interventions. Pain intensity and functional disability were evaluated using standardized assessment tools before the procedure and during follow-up visits at 3 weeks and 3 months after treatment. The primary objective was to compare pain relief between the two techniques at 3 months. Secondary objectives included evaluation of functional improvement and procedure-related complications. The results of this study provide comparative information on the effectiveness and safety of these two commonly used radiofrequency techniques and may help guide clinicians in selecting appropriate interventional treatments for patients with chronic coccydynia.

This study was designed as a single-center, prospective, randomized clinical trial to compare two radiofrequency ablation techniques used for the treatment of chronic coccydynia: fluoroscopy-guided ganglion impar thermal radiofrequency ablation and ultrasound-guided coccygeal nerve thermal radiofrequency ablation.Adult patients with chronic coccydynia persisting for more than three months and refractory to conservative medical management were evaluated for eligibility. Following informed consent, eligible participants were randomly assigned in a 1:1 ratio to undergo either ganglion impar radiofrequency ablation or coccygeal nerve radiofrequency ablation. Randomization was performed prior to the intervention.All procedures were conducted under standard sterile conditions by experienced pain physicians. Ganglion impar radiofrequency ablation was performed under fluoroscopic guidance, while coccygeal nerve radiofrequency ablation was performed under ultrasound guidance. Both interventions followed established clinical protocols routinely used in interventional pain practice. Pain intensity was assessed using the Numeric Rating Scale (NRS), and functional status was evaluated using the modified Oswestry Disability Index (MODI). Assessments were conducted at baseline prior to the procedure and during follow-up visits at 3 weeks and 3 months after treatment. Adverse events and procedure-related complications were monitored and recorded throughout the follow-up period. The primary outcome measure was the proportion of patients achieving at least a 50% reduction in NRS score at 3 months compared with baseline. Secondary outcome measures included changes in MODI scores at 3 months and the incidence of procedure-related complications. The study protocol was approved by the local ethics committee, and the study was conducted in accordance with the principles of the Declaration of Helsinki.

Inclusion Criteria:

• Adults aged 18 to 75 years Diagnosis of chronic coccydynia lasting longer than 3 months Numeric Rating Scale (NRS) score ≥ 4 at baseline Inadequate response to conservative medical treatment Ability to understand the study procedures and provide written informed consent

Exclusion Criteria:

Acute coccygeal fracture or recent trauma Local or systemic infection Known malignancy involving the pelvic or sacrococcygeal region Coagulation disorders or ongoing anticoagulant therapy that cannot be safely discontinued Known allergy to local anesthetics or materials used in the procedure Severe psychiatric disorders or cognitive impairment interfering with study participation Pregnancy or breastfeeding

De-identified individual participant data underlying the results reported in the published article.

3 months after publication

Access to de-identified individual participant data and supporting documents, including the study protocol and statistical analysis plan, will be granted to qualified researchers upon reasonable request. Requests will be reviewed by the study investigators and must include a methodologically sound proposal. Data sharing will be conducted in accordance with institutional policies and applicable data protection regulations.