Comparison of Ganglion Impar Radiofrequency Ablation and Phenol Neurolysis Techniques for Chronic Coccydynia Treatment

NCT ID: NCT07021365

Last Updated: 2025-06-17

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

NOT_YET_RECRUITING

Clinical Phase

NA

Total Enrollment

30 participants

Study Classification

INTERVENTIONAL

Study Start Date

2025-07-31

Study Completion Date

2026-03-31

Brief Summary

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Radiofrequency ablation and phenol neurolysis of the ganglion impar are methods used in cases unresponsive to medication, particularly in patients who derive short-term or partial relief from the initial ganglion impar block. In clinical practice, clinicians frequently use these two injections in patients with treatment-resistant pain who only partially benefit from the initial blockade procedure.

To date, the medical literature lacks a comprehensive study comparing the efficacy of radiofrequency ablation and phenol neurolysis in patients who partially benefit from ganglion impar block. Therefore, this study is designed to compare the effectiveness of these two methods in patients with chronic coccydynia.

Detailed Description

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Ganglion impar radiofrequency ablation and phenol neurolysis are treatment options for patients who do not respond to medication, especially those experiencing only temporary or partial relief from an initial ganglion impar block. In clinical practice, these two injection techniques are commonly employed in managing persistent pain in such cases.

Radiofrequency Ablation (RFA):

This technique aims to eliminate pain by thermally damaging the nerves that carry pain sensations. Under real-time imaging guidance, a radiofrequency needle is advanced through the intervertebral disc from the tailbone region to the anatomical area called the ganglion impar. The needle tip location is confirmed with contrast dye. At this point, motor and sensory stimulation is applied to ensure the needle is not affecting motor function and to identify the site where the pain stimulus matches the patient's complaint. Once confirmed, heat application is initiated. Prior to heat delivery, a local anesthetic is administered to ensure the procedure is painless.

Phenol Neurolysis:

This method aims to chemically destroy the nerves carrying pain signals from the coccyx area using phenol. The procedure is performed similarly to RFA: a radiofrequency needle is inserted through the disc between spinal bones under real-time imaging guidance to reach the ganglion impar. After confirming the needle position with contrast dye, a local anesthetic is administered, and then phenol is applied to chemically ablate the sensory fibers without pain.

No major complications have been reported in the literature regarding these two procedures. However, minor complications may occur, such as vasovagal reactions (temporary fainting), minor bleeding, infection, and vascular injection.

Study Design:

The study will include patients under the care of the Marmara University Pain Medicine Department who have not responded to medication and have received short-term or partial benefit from an initial ganglion impar block. These patients will be randomly assigned via computer software into two groups. One group will undergo the radiofrequency ablation procedure described above, and the other group will receive phenol neurolysis. The patients will be followed for six months, and the effectiveness of these two widely used but yet-to-be-compared treatments will be evaluated.

Conditions

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Coccygodynia Coccydynia

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

TRIPLE

Caregivers Investigators Outcome Assessors

Study Groups

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Ganglion Impar Radiofrequency Ablation

Group Type ACTIVE_COMPARATOR

Radiofrequency ablation alone

Intervention Type DEVICE

In patients diagnosed with chronic coccydynia, a ganglion impar block is initially performed following conservative treatment. In cases where this intervention provides limited benefit, ganglion impar radiofrequency (RF) ablation-routinely used in clinical practice-will be performed by an experienced pain specialist (SŞ) with at least 10 years of expertise in this procedure.

Using fluoroscopic guidance and intermittent imaging, a 100 mm RF cannula with an injection tube will be advanced trans-coccygeally. After confirming the needle's position at the site of the ganglion impar in front of the coccyx with 1-2 mL of contrast agent (iohexol), sensory stimulation will be applied via the RF generator to confirm that the needle tip is at the patient's pain site. Motor stimulation will also be performed to ensure there is no muscle contraction. At this stage, 2 mL of lidocaine will be administered before initiating ablation at 80°C for 90 seconds.

Ganglion Impar Phenol Neurolysis

Group Type ACTIVE_COMPARATOR

Phenol Injection

Intervention Type DRUG

n patients diagnosed with chronic coccydynia, a ganglion impar block is initially performed following conservative treatment. In cases where this intervention provides limited benefit, ganglion impar phenol neurolysis is performed. A short-acting local anesthetic (3-4 mL of 1% prilocaine) will be administered into the skin and subcutaneous tissues. A 90 mm 22-gauge Quincke-tipped spinal needle will be advanced via the trans-coccygeal route under fluoroscopic guidance with intermittent imaging. The needle's position in the area anterior to the coccyx, where the ganglion impar is located, will be confirmed using 1-2 mL of contrast agent (iohexol). If the desired spread of contrast is observed, 5 mL of 7% phenol will be injected.

Interventions

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Phenol Injection

n patients diagnosed with chronic coccydynia, a ganglion impar block is initially performed following conservative treatment. In cases where this intervention provides limited benefit, ganglion impar phenol neurolysis is performed. A short-acting local anesthetic (3-4 mL of 1% prilocaine) will be administered into the skin and subcutaneous tissues. A 90 mm 22-gauge Quincke-tipped spinal needle will be advanced via the trans-coccygeal route under fluoroscopic guidance with intermittent imaging. The needle's position in the area anterior to the coccyx, where the ganglion impar is located, will be confirmed using 1-2 mL of contrast agent (iohexol). If the desired spread of contrast is observed, 5 mL of 7% phenol will be injected.

Intervention Type DRUG

Radiofrequency ablation alone

In patients diagnosed with chronic coccydynia, a ganglion impar block is initially performed following conservative treatment. In cases where this intervention provides limited benefit, ganglion impar radiofrequency (RF) ablation-routinely used in clinical practice-will be performed by an experienced pain specialist (SŞ) with at least 10 years of expertise in this procedure.

Using fluoroscopic guidance and intermittent imaging, a 100 mm RF cannula with an injection tube will be advanced trans-coccygeally. After confirming the needle's position at the site of the ganglion impar in front of the coccyx with 1-2 mL of contrast agent (iohexol), sensory stimulation will be applied via the RF generator to confirm that the needle tip is at the patient's pain site. Motor stimulation will also be performed to ensure there is no muscle contraction. At this stage, 2 mL of lidocaine will be administered before initiating ablation at 80°C for 90 seconds.

Intervention Type DEVICE

Eligibility Criteria

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Inclusion Criteria

* Age between 18 and 65 years
* Presence of chronic coccydynia lasting at least 3 months
* Pre-procedural pain score of 4 or higher on the Numeric Rating Scale (NRS)
* Patients who have undergone a ganglion impar block within the last 3 months and experienced limited benefit (i.e., less than 50% reduction in pain compared to pre-treatment) and/or short-term relief (less than 4 weeks)

Exclusion Criteria

* History of surgery involving the sacrococcygeal region
* Prior treatment with ganglion impar phenol neurolysis or radiofrequency ablation
* Coagulopathies (bleeding disorders)
* Infection
* Spondylolisthesis, scoliosis, or lumbar spinal stenosis
* Malignancy
* Pregnancy
* History of allergic reaction to the administered injectates
* History of major psychiatric illness
Minimum Eligible Age

18 Years

Maximum Eligible Age

65 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Marmara University

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Locations

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Marmara University

Istanbul, Istanbul, Turkey (Türkiye)

Site Status

Countries

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Turkey (Türkiye)

Central Contacts

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Savas Sencan, Associate Professor

Role: CONTACT

00905370665713

Merve Sekizkardes, Medical Doctor

Role: CONTACT

00905367445551

Facility Contacts

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Merve Sekizkardes, Medical Doctor

Role: primary

00905367445551

References

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Karadimas EJ, Trypsiannis G, Giannoudis PV. Surgical treatment of coccygodynia: an analytic review of the literature. Eur Spine J. 2011 May;20(5):698-705. doi: 10.1007/s00586-010-1617-1. Epub 2010 Nov 3.

Reference Type BACKGROUND
PMID: 21046173 (View on PubMed)

Sagir O, Demir HF, Ugun F, Atik B. Retrospective evaluation of pain in patients with coccydynia who underwent impar ganglion block. BMC Anesthesiol. 2020 May 11;20(1):110. doi: 10.1186/s12871-020-01034-6.

Reference Type BACKGROUND
PMID: 32393277 (View on PubMed)

Demircay E, Kabatas S, Cansever T, Yilmaz C, Tuncay C, Altinors N. Radiofrequency thermocoagulation of ganglion impar in the management of coccydynia: preliminary results. Turk Neurosurg. 2010 Jul;20(3):328-33. doi: 10.5137/1019-5149.JTN.2852-09.0.

Reference Type BACKGROUND
PMID: 20669105 (View on PubMed)

Howard PD, Dolan AN, Falco AN, Holland BM, Wilkinson CF, Zink AM. A comparison of conservative interventions and their effectiveness for coccydynia: a systematic review. J Man Manip Ther. 2013 Nov;21(4):213-9. doi: 10.1179/2042618613Y.0000000040.

Reference Type BACKGROUND
PMID: 24421634 (View on PubMed)

Kircelli A, Demircay E, Ozel O, Coven I, Isik S, Civelek E, Kabatas S. Radiofrequency Thermocoagulation of the Ganglion Impar for Coccydynia Management: Long-Term Effects. Pain Pract. 2019 Jan;19(1):9-15. doi: 10.1111/papr.12698. Epub 2018 May 16.

Reference Type BACKGROUND
PMID: 29617062 (View on PubMed)

Sencan S, Kenis-Coskun O, Demir FGU, Cuce I, Ercalik T, Gunduz OH. Ganglion Impar block improves neuropathic pain in coccygodynia: A preliminary report. Neurol Neurochir Pol. 2018 Sep-Oct;52(5):612-617. doi: 10.1016/j.pjnns.2018.08.006. Epub 2018 Aug 28.

Reference Type BACKGROUND
PMID: 30195465 (View on PubMed)

Other Identifiers

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09.2024.1470

Identifier Type: -

Identifier Source: org_study_id

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