Radiofrequency Ablation in Coccydynia: A Case Series and Comprehensive, Evidence-Based Review

A novel approach to refractory coccydynia: ultrasound- fluoroscopy-guided cryoablation of sacrococcygeal nerve

Coccydynia, also termed chronic pain in the tailbone, is a complex condition with limited treatment options for refractory cases. This case series introduces a novel approach for treating refractory coccydynia using cryoablation of the sacrococcygeal nerves under combined ultrasound and fluoroscopy guidance. Two female patients, suffering from chronic pain for over six months and unresponsive to conservative interventions, underwent cryoablation. Both patients reported significant pain relief, with more than 50% reduction in their numeric rating scale scores, and no major complications were observed during or after the procedure. Furthermore, we propose a clinical treatment algorithm to assist in selecting appropriate interventions for refractory coccydynia, based on the anatomical source of the pain. The findings suggest that cryoablation may be a valuable option for patients with persistent coccygeal pain; however, larger prospective studies are required to confirm its efficacy and long-term safety.

A description and outcome evaluation of sacrococcygeal joint radiofrequency neurotomy for treatment of chronic coccydynia - A dorsal approach

Background

Coccydynia is a condition characterized by pain and tenderness in the coccyx region of the spine. Chronic coccydynia (≥3-months) management remains a clinical challenge. Radiofrequency neurotomy (RFN) targeting the sacrococcygeal joint (SCJ) and/or 1st intercoccygeal joint (ICJ) margins has emerged as an alternative, minimally invasive intervention for refractory coccydynia.

Objective

The objective of this study was to evaluate the safety and effectiveness of an RFN technique targeting the dorsal aspect of SCJ and/or 1st ICJ for treatment of patients with chronic coccydynia.

Methods

Retrospective analysis of prospective outcomes for patients with chronic coccydynia (≥3-months) who underwent RFN to dorsal SCJ and/or 1st ICJ between 2009 - 2023. RFN technique was a dorsal approach targeting the distal sacrum and proximal coccyx, which form the SCJ or 1st ICJ margins. Numerical rating scale (NRS) and Pain Disability Quality-of-Life Questionnaire-Spine (PDQQ-S) scores were completed pre- and 3-months post-RFN. Successful RFN was defined as ≥50% reduction or minimal clinical important difference (MCID) in PDQQ-S and NRS pain scores. The primary outcome measures were the proportion of patients achieving ≥50% reduction in NRS pain and PDDQ-S scores following primary and repeat RFN to SCJ and/or 1st ICJ. Secondary outcomes included the proportion of patients achieving MCID on NRS pain and PDQQ-S scores following RFN, as well as mean NRS and PDQQ-S scores pre- and 3-months post-RFN, and magnitude of improvement for patients following successful RFN procedures.

Results

A total of 52 RFN procedures (n = 30 primary, and n = 22 repeat procedures) were performed on 30 patients (female = 25, male = 5, mean age 55.1 ± 13.0yrs). Ten patients (33.3%; 95% CI = 17.3-52.8) reported ≥50% pain reduction as measured by NRS pain and PDQQ-S scores following primary SCJ and/or 1st ICJ RFN at 3-months follow-up. Fifteen patients (50%; 95% CI = 31.3-68.7) reported MCID NRS pain reduction and 12 patients (40.0%; 95% CI = 22.7-59.4) reported MCID PDQQ-S scores at 3-months following primary RFN. The mean magnitude of improvement for patients with primary successful RFN, as defined as ≥50% reduction in either NRS pain or PDQQ-S scores, was 77.4% (±SD 21.4%) and 74.9% (±SD = 19.9%), respectively. Similarly, the mean magnitude of improvement for patients with successful RFN, as defined by MCID reduction in NRS pain or PDQQ-S scores, was 62.6% (±SD = 28.2%) and 69.3% (±SD = 22.3%), respectively. At 3-months follow-up, 14 patients (63.6%; 95% CI = 40.7-82.8) reported ≥50% pain reduction as measured by either NRS pain and PDQQ-S scores following repeat RFN. Nineteen patients (86.4%; 95% CI = 65.1-97.1) reported MCID NRS pain reduction and 16 patients (72.7%; 95% CI = 49.8-89.3) reported MCID PDQQ-S scores at 3-months following repeat RFN. Statistically significant differences were observed between pre- and post-RFN NRS pain and PDQQ-S scores (p < 0.005) in both primary and repeat procedures.

Discussion/conclusion

This study represents an introductory step in evaluating the efficacy of a dorsal approach RFN technique targeting the SCJ and/or 1st ICJ as a treatment option for chronic coccydynia. Primary RFN demonstrated pain reduction and improvement in function at 3-months in 33.3% of patients. Several limitations remain, including heterogeneity in patient population, small sample size, and no control groups. Future detailed investigations include cadaveric studies to clarify sensory innervation and enhance reliability of our targets during RFN. Larger prospective studies of long-term outcomes, including comparison with control groups, are required to further evaluate the efficacy of our dorsal RFN approach.

Comparative effects of radial and focused extracorporeal shock wave therapies in coccydynia

Objectives

This study was conducted to compare the effects of radial and focused extracorporeal shock wave therapy (ESWT) in patients with coccydynia.

Patients and methods

In this prospective randomized double-blind study conducted between March 2021 and October 2021, 60 patients with coccydynia (50 males, 10 females; mean age: 35.9±12.0 years, range 18 to 65 years) were randomized into three groups (n=20) according to different wave types of ESWT: focused, radial, and sham. The Visual Analog Scale (VAS) was used for pain assessment, and the Oswestry Disability Index (ODI) was used for functional assessment in all patients before the treatment (baseline), after the completion of four sessions of treatment (fourth week), one month after the end of the treatment (eighth week), and three months after the end of the treatment (16^th week).

Results

The mean body mass index of the participants was 26.2±3.0. Compared to baseline, the VAS scores at four weeks were reduced only in the radial ESWT group (p<0.05). Compared to baseline, the VAS and ODI scores at eight and 16 weeks were significantly reduced in both the focused and radial ESWT groups (p<0.05 for all). The radial ESWT group was significantly superior to the focused ESWT group in the comparisons between the groups at four weeks in the VAS values and at 16 weeks in the ODI scores (p<0.05 for all).

Conclusion

Radial and focused ESWT are both effective in treating coccydynia compared to sham ESWT. However, radial ESWT may be more effective in the treatment of coccydynia.