Comparison of Single- and Double-Level Radiofrequency Ablation for Chronic Coccydynia

This study aims to compare two commonly used radiofrequency ablation (RFA) techniques for the treatment of chronic tailbone (coccyx) pain, also known as coccydynia. Chronic coccydynia can significantly impair daily activities and reduce quality of life, particularly in patients who do not respond adequately to conservative treatments. Participants in this study will be randomly assigned to receive either a single-level or double-level radiofrequency ablation (RFA) procedure targeting the coccygeal nerve pathways. These procedures are minimally invasive and are routinely performed in pain management practice. The primary objective of the study is to determine which technique provides superior pain relief and functional improvement. Patients will be followed for up to two months after the procedure, and pain intensity and quality of life will be evaluated using validated outcome measures. The results of this study may help optimize interventional treatment strategies for patients suffering from chronic coccydynia.

Study Overview

• Status: Not yet recruiting
• Conditions: Chronic Coccydynia
• Intervention / Treatment: Procedure: Single-Level Ganglion Impar Radiofrequency Ablation; Procedure: Double-Level Ganglion Impar Radiofrequency Ablation

Detailed Description

Chronic coccydynia is a persistent pain condition localized to the coccygeal region, often exacerbated by sitting and significantly impairing quality of life. While conservative treatments such as pharmacotherapy, physical therapy, and local injections may provide relief, a subset of patients remains refractory to these approaches. Radiofrequency ablation (RFA) targeting the ganglion impar has emerged as an effective minimally invasive option for managing refractory coccydynia.

Different technical approaches to ganglion impar RFA have been described, including single-level and double-level lesioning techniques. However, there is limited evidence directly comparing the clinical efficacy of these approaches. It remains unclear whether creating lesions at two levels provides superior pain relief and functional outcomes compared to a single-level approach.

This prospective randomized controlled study aims to compare the effectiveness of single-level versus double-level radiofrequency ablation of the ganglion impar in patients with chronic coccydynia who previously responded to diagnostic or therapeutic ganglion impar block but experienced recurrence of pain. The primary objective is to evaluate pain reduction, while secondary objectives include assessment of functional status and quality of life over a two-month follow-up period.

All procedures will be performed under fluoroscopic guidance using standardized techniques. Patients will be evaluated at baseline and at predefined follow-up intervals using validated outcome measures. The findings of this study are expected to contribute to optimizing interventional treatment strategies for chronic coccydynia.

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients with coccygeal pain lasting longer than 2 months
• Patients who experienced significant pain relief (≥50% reduction) after a ganglion impar block performed within the last 6 months, but whose pain has subsequently recurred
• Patients who provide informed consent to participate in the study

Exclusion Criteria:

• Acute coccydynia (pain duration less than 2 months)
• Patients who did not achieve significant benefit (<50% pain reduction) from prior ganglion impar block
• Patients with severe neurological or psychiatric disorders that impair communication or ability to follow instructions

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Single-Level Radiofrequency Ablation; Participants in this arm will undergo fluoroscopy-guided single-level radiofrequency ablation of the ganglion impar using a standardized technique. The procedure will be performed under sterile conditions by experienced pain specialists.	Procedure: Single-Level Ganglion Impar Radiofrequency Ablation; Fluoroscopy-guided radiofrequency ablation of the ganglion impar will be performed using a transsacrococcygeal approach. After appropriate needle placement and confirmation, thermal radiofrequency lesioning will be applied at a single level using standardized parameters.
Active Comparator: Double-Level Radiofrequency Ablation; Participants in this arm will undergo fluoroscopy-guided double-level radiofrequency ablation of the ganglion impar, targeting two adjacent levels using a standardized technique. The procedure will be performed under sterile conditions by experienced pain specialists.	Procedure: Double-Level Ganglion Impar Radiofrequency Ablation; Fluoroscopy-guided radiofrequency ablation of the ganglion impar will be performed using a combined transsacrococcygeal and transcoccygeal approach. After appropriate needle placement and confirmation, thermal radiofrequency lesioning will be applied at two adjacent levels using standardized parameters.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in pain intensity (Numeric Rating Scale, NRS)	Pain intensity will be assessed using the Numeric Rating Scale (NRS), a self-reported scale ranging from 0 (no pain) to 10 (worst imaginable pain). Changes in pain scores from baseline will be evaluated at 1 hour, 3 weeks, and 2 months after the procedure. Higher scores indicate worse pain intensity.	Baseline, 1 hour, 3 weeks, and 2 months post-procedure

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Functional status (Paris Coccydynia Questionnaire)	Functional status and the impact on daily living will be assessed using the Paris Coccydynia Questionnaire before and after radiofrequency ablation. Changes from baseline will be evaluated.	Baseline, 3 weeks, and 2 months post-procedure
Quality of life (EuroQol-5D-3L, EQ-5D-3L)	Quality of life will be assessed using the EuroQol 5-Dimension 3-Level (EQ-5D-3L) questionnaire, which includes a descriptive system and a visual analog scale. The EQ-5D-3L index value typically ranges from less than 0 (health states worse than death) to 1 (perfect health). Changes from baseline will be evaluated at follow-up time points. Higher scores indicate better health-related quality of life.	Baseline, 3 weeks, and 2 months post-procedure

Collaborators and Investigators

• Sponsor: Marmara University

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): May 1, 2027
• Study Completion (Estimated): November 1, 2027

Study Registration Dates

• First Submitted: March 29, 2026
• First Submitted That Met QC Criteria: March 29, 2026
• First Posted (Actual): April 3, 2026

Study Record Updates

• Last Update Posted (Actual): April 22, 2026
• Last Update Submitted That Met QC Criteria: April 18, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Radiofrequency ablation; Interventional pain management; Chronic coccydynia; Ganglion impar
• Other Study ID Numbers: 09.2026.718

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No