Coccydynia refers to a significant pain, that does not radiate, in and around the coccyx region. This symptom is typically worsen while sitting, especially on hard surfaces, standing up from sitting position and standing for long time. The steroid and anesthetic injection to the sacrococcygeal, intercoccygeal joints and impar ganglions are the most commonly cited second line management option in the literatures for refractor cases. The coccygeal nerve blockade or radiofrequency ablation is also used for coccydynia especially for traumatic cases. The aim of the study is; to evaluate the efficacy of ultrasound-guided sacrococcygeal and/or intercoccygeal joint injection in coccydynia and to investigate whether coccygeal nerve blockade has an additional contribution to this treatment.

Coccydynia refers to a significant pain, that does not radiate, in and around the coccyx region. This symptom is typically worsen while sitting, especially on hard surfaces, standing up from sitting position and standing for a long time. There are several uncertainties with respect to the origin of etiology and the commonest factor for coccydynia is external and internal trauma such as falling, giving birth. Also there are idiopathic cases. The risk of coccydynia progression is higher in the female gender and when obesity is present. The morphology and hypermobility of coccyx are associated with coccydynia and degenerative changes in the intercoccygeal discs have been incriminated to be a cause of pain in 41% of idiopathic and 44% of traumatic coccydynia. The other causes such as infections, tumors such as chordoma, osteoid osteoma or notochordal cell tumors. The antero-posterior (AP) and lateral radiographs are primary imagining modality to rule out these conditions and also to investigate predisposing factors for coccydynia such as bony spicule, retroverted coccyx, subluxation or scoliosis of coccyx. The radiographs are also useful to find out any fracture or dislocation in cause of trauma. Angular mobility evaluation is done by dynamic imaging modalities and still mostly used method is dynamic radiographs which are performed in standing and seated position at the point of maximum pain. Magnetic resonance imaging (MRI) is used for chronic cases to identify most accurate diagnosis and to find exact irritation point and also for ruling out the infections and tumors. A wide range of treatment options have been described till date and conservative therapy such as heat, ice, seat cushions, topical anesthetic and oral/topical non-steroidal anti-inflammatory drugs and intrarectal/intravaginal manual manipulation is successful in %90 of cases. The second line management option for refractor cases is steroid and anesthetic injections however, site of injection is controversial. The sacrococcygeal, intercoccygeal joints and impar ganglions are the most commonly sites for injections cited in the literatures. The success rate of the sacrococcygeal and intercoccygeal joints injections are reported as 60% in most of the studies and the symptoms of nearly one third of the patients relapse within one year. The coccygectomy is an effective modality for these refractory cases but, postoperative complications lead to continue to search conservative treatments options. The innervation of coccyx posteriorly is mostly done by paired of coccygeal nerves and the posterior rami of fourth and fifth sacral nerves which are joining with coccygeal nerves. The coccygeal nerves innervate the coccygeal periosteum, sacrococcygeal joint and the skin over the coccyx. Pain occur at posterior region, after trauma such as falling or long time sitting may be elicited by coccygeal nerves. The coccygeal nerve emerges from the conus medullaris and pierces the posterior sacrococcygeal ligament while it descends in sacral canal. At the level of coccygeal cornu (CC), it is in the the subcutaneous layer and medial to the CC. Therefore coccygeal nerve blockade or radiofrequency ablation is also used for coccydynia especially for traumatic cases. Image guidance such as ultrasound (USG), fluoroscopy, computerized tomography (CT) provide visualization of the needle into the target and improves the accuracy of injections. The use of USG improve the identification of musculoskeletal structures and it spares the patient radiation exposure. It has advantage over the other modalities in that it is cost effective, portable and adapted in multiple disciplines and it has therapeutic safety.

In this study, it is planned to assessed the change of pain severity of the patients who had sacrococcygeal and/or intercoccygeal joint injection with/without coccygeal nerve block in our clinic due to the complaint of coccydynia resistant to conservative treatment methods, by applying the Numeric Rating Scale (NRS). Patients are asked to indicate rates of their pain on the day of presentation during palpation of coccyx, at the first sitting, sitting on soft and hard surface, standing up from sitting position, standing for long time, during defecation, sexual intercourse and menstrual cycle, and also 1 week, 4 weeks, 3 moths and 6 months after the injection for each. Participants are asked to indicate rates of their pain according to NRS during sitting, standing up from sitting position and on palpation of coccyx at the first hour of injection. The pain elicited by injection is also asked after one hour, to determine the effect of coccygeal nerve block which is applied before the sacrococcygeal and/or intercoccygeal joint injection. The second outcome measurement method is assessing the change of pain-free sitting time as a minute before the injection, and one hour, 1 week, 4 weeks, 3 moths and 6 months after the injection.The Oswestry Disability Index for patients with low back pain, Short Form-12 (SF-12) are applied to the participants before the procedure and, at the 1st month, 3rd months and 6 months after the treatment. In these ways, it is planned to evaluate the efficacy of sacrococcygeal and/or intercoccygeal joint injection and also to understand does any additive effect of coccygeal nerve blockade to this treatment approach.

Inclusion Criteria:

1. Aged 18-65 years
2. Patients who have coccygeal pain and have not benefited from conservative treatment
3. Be able to understand enough Turkish to complete the outcome questionnaire
4. Patients whose informed consent was obtained for participation in the study

Exclusion Criteria:

1. Fibromyalgia
2. History of surgery for coccydynia
3. Pregnancy or breastfeeding
4. Inflammatory disease which effect the spine
5. Malignancy
6. Coagulation disorders
7. Infection