Pain in the region of the coccyx is referred to as coccygodynia. Despite being recognised for many centuries, coccydynia remains an unsolved mystery because of the perceived uncertainty in identifying the origin of the pain.
Coccygodynia is a painful disorder characterised by coccygeal pain typically exaggerated by pressure. It remains an enigma because of the perceived unpredictability of the origin of the pain, psychological traits that may be associated with the disorder, the presence of diverse treatment options, and varied outcomes. Most cases can be managed conservatively, though injection treatments may help some patients with refractory pain.
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.
Coccygeal pain may arise either from the coccyx itself or may be referred to the coccyx from surrounding structures, or it may be neurogenic in origin, arising from the nerve roots, plexus or peripheral nerves that travel to or through the coccyx.
The most common cause of coccydynia is single direct axial trauma such as a fall directly onto the coccyx or, as during the post-partum period, due to a subtle form of cumulative trauma that occurs due to sitting awkwardly. Raised body mass index is a risk factor for the development of both idiopathic and posttraumatic coccydynia. Owing to the presence of discs or disc-like structures in gross anatomical specimens, a degenerative cause of pain has been considered.
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.
Conservative treatment remains the mainstay of treatment. The spectrum of treatment ranges from simple measures such as the use of laxatives, non-steroidal anti-inflammatory drugs, hot baths, ring-shaped cushions, ergonomic adaptations to physical therapy, manipulation, sacrococcygeal injections, ganglion impar blocks, psychotherapy and coccygectomy (partial or complete). Conservative management is successful in approximately 90% of patients.
Pericoccygeal linjections 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 the tip of the coccyx.
Caudal epidural injections can be considered in patients who do not respond to injections around the coccyx or if they get only short term pain relief from coccyx injections.
Ganglion impar block can be performed in patients who fail to respond to coccyx injections and caudal epidural injections