Coccygodynia is a disabling pain in the coccyx exacerbated by sitting or rising from sitting. The pain is often pulling or lancinating in quality, may radiate to the sacrum or buttock, and may coexist with lower back pain. Contributing of many physiologic and psychological factors to its etiology, it may be traumatic or idiopathic in origin. Many risk factors are known such as trauma, female gender and obesity. Despite the identification of chronic coccygeal pain hundreds of years ago, its treatment can be difficult and sometimes controversial because of the multifactorial nature of coccygeal pain. Most cases of coccygodynia resolve within weeks to months with or without conservative treatment, but for a few patients, the pain can become chronic and debilitating. First-line treatment options include analgesic drugs, cushion, sit baths, and manuel therapy. Interventional procedures for pain management can be applied to patients who have no response to other conservative modalities. Ganglion impar block and caudal epidural steroid injection are two treatment options for chronic coccygodynia and both of them can be applied by guidance of fluoroscopy and ultrasonography. Radiofrequency ablation is the other option for treatment and eventually, surgical intervention can be done for patients who have refractory pain despite other treatments.

Although efficacy of two interventional procedure for chronic coccygodynia, ganglion impar block and caudal epidural steroid injection, has been well known, no study is exist comparing the efficacy of them. We aimed to compare the efficacy of ganglion impar block and caudal epidural steroid injection in chronic coccygodynia.

The main purpose of this prospective study is the compare the efficacy of fluoroscopy-guided ganglion impar block and caudal epidural steroid injection in patients with chronic coccygodynia. Patients with chronic coccygeal pain are randomly divided into two groups based on the type of the interventional procedure: Group A, fluoroscopy-guided ganglion impar block group and, group B, fluoroscopy-guided caudal epidural steroid injection group. The patients who have chronic coccygeal pain not responding to other conservative treatments will be recruited from physical medicine&rehabilitation and pain medicine outpatient clinics. Detailed information including all aspects of interventional procedures will be given to patients, and inform consent will be obtained. Pain severity will be assessed using Numerical Rating Scale (NRS) as primary outcome. Quality of life and neuropathic pain component will be evaluated with Short Form-12 (SF-12) Questionnaire and Leeds Assessment of Neuropathic Symptoms&Signs Pain Scale (LANSS) as secondary outcomes, respectively. All assessments will be done at pre-interventional period, three weeks and three months after the procedure, with the exception of NRS, it will be also assessed at first hour post-procedure. All assessments will be done by clinician blinding the treatment groups.

Inclusion Criteria:

• Patients diagnosed with chronic coccygodynia between the ages of 18 and 65
• Intractable pain over the coccyx despite conservative treatment

Exclusion Criteria:

• History of ganglion impar blockade and/or caudal epidural steroid injection carried out in the last 3 months
• History of lumbar surgery
• Systemic and/or local infections
• Malignancy
• Bleeding diathesis
• Acute fracture
• Known allergy to contrast material and/or local anesthetic substances
• Known history of any psychiatric disorder
• History of pregnancy