Coccyx Injection

The coccyx is a triangular bone consisting of three to five segments: the first and largest of these vertebral segments articulates with the sacrum. The last three segments diminish in size and usually form a single piece of bone. The disc spaces in this region are extremely variable. Intact discs, discs with extensive clefts, discs with cystic or fibrocystic changes and discs replaced by synovial joints have all been reported.

Women are five times more commonly affected than men. The main symptom is tenderness and pain, or an ache localised in the region of the lower sacrum, the coccyx, or in the adjacent muscles and soft tissues. The patient usually points to the coccyx as the site of pain. The severity of the pain is dependent on various predisposing factors, such as the duration of time spent sitting. Dyspareunia and piriformis syndrome have been infrequently associated with coccydynia. The character of the pain appears to be more related to spasm of the levator muscle, as patients complain of pain during defecation or sexual intercourse.

Coccydynia is a dynamic disorder and hence static scans are unlikely to be helpful.

Pericoccygeal injections with local anaesthetic and steroids can be helpful although there is no clear consensus in the literature regarding the site of injection.

Injection of local anaesthetic and steroid can be helpful in patients who do not respond to conservative management. The injection is performed under fluoroscopy or ultrasound guidance to target the sacrococcygeal junction as well as tip of the coccyx.

Injections are generally avoided in patients with systemic infection or skin infection over puncture site, bleeding disorders or coagulopathy, allergy to local anaesthetics or any of the medications to be administered.

The procedure is done on an outpatient basis. The procedure is performed under fluoroscopic guidance or ultrasound guidance to ensure accuracy of needle placement. Patients need to be aware that the outcome of the procedure is variable and they may not receive the desired benefits. Similarly, they must be aware of the transient nature of the therapeutic benefits and that there may need repeated injections.

Generally a mixture of local anaesthetic and steroid is injected. The anaesthetic is probably responsible for immediate pain relief, whereas steroids are believed to be responsible for pain relief 2–6 days after their administration.

Patient who get only temporary pain relief from coccyx injections could be considered for ganglion impar block as this may provide longer term pain relief.

Please click here for more information regarding ganglion impar block

Complications are rare, particularly if the injections are performed using a precise needle-positioning technique. Possible complications include bruising, infection, hematoma, nerve injury and reaction to the injectates. Infection can be avoided with appropriate aseptic precautions. Severe allergic reactions to local anaesthetics are uncommon. Steroid injections may produce local reactions, occurring most often immediately after injection. These local reactions last for 24 to 48 hours, and are relieved by application of ice packs. Post-procedural pain flare-up may occasionally occur, and may be treated with pain killers. Neurological complications including paraesthesias and numbness have been described but are extremely rare.