The anatomy of the coccyx
The coccyx, also known as the tailbone, is the smallest bone situated at the bottom end of the spinal column. The coccyx performs the function of anchoring multiple muscles in the pelvic area, acting as a bone which bears the weight of the body when a person is sitting.
Causes of coccyx pain
The most common cause of persistent coccyx pain, or coccydynia, is direct trauma, as a result of an injury or otherwise contributing to discomfort and pain. In other cases, the pain has no identifiable source, and this is known as idiopathic coccydynia.
Coccydynia can be caused by hypermobility, which stresses the joint between the coccyx and the sacrum through too much movement; limited mobility of the coccyx, which causes it to be pushed outwards when sitting and can increase pressure on the sacrococcygeal joint and bones; or a dislocation of the sacrococcygeal joint at the front or rear of the tailbone, although these cases are rare.
Coccyx injection procedure
There are a number of coccyx injection procedures available to patients, and we will run through some common types below. The procedure will take place in theatre under full aseptic conditions with the patient on his or her stomach. The injection site is thoroughly cleansed and numbed with an anaesthetic before fluoroscopy (live X-ray) is used to guide the needle into the right area to avoid organ injury. A small needle in the back of your hand can be used to administer sedation or in case of an emergency.
Coccygeal injection consisting of direct administration of steroid and local anaesthetic.
Ganglion impar injection treats coccyx pain by blocking the pain signals to the brain, and these injections can be both diagnostic and therapeutic.
A caudal epidural injection for coccyx pain targets the nerves at the spine’s lower end and is administered in the epidural space. This space can be accessed through a hole which is found at the lower end of the sacrum.
A coccygeal nerve block is also used to address coccyx pain and is a minimally invasive treatment focused on the tailbone.
Pulsed radiofrequency of Coccygeal Nerves is a relatively new treatment for coccyx pain which uses neurostimulation therapy in order to modulate the function of the nerve. As a result the pain signals to the brain are modified by the electrical pulse, meaning the patient does not feel the same pain as he or she did previously. This may be indicated if there is a significant reduction in the pain levels after the coccygeal nerve block to prolong the benefit. This procedure can be described as a ‘retuning’ of the nerves so that they modulate pain transmission.
Patients are then monitored in a recovery area before transfer to the ward and discharge home. Patients may experience a numb feeling for a few hours. Pain at the injection site may increase for seven or more days. It is advisable to rest for 24 hours and resume stretches and exercises when the pain eases.
There is a variable response to injection treatment. It is important to discuss both the benefits and risks of the procedure with your doctor before any agreement to undergo the procedure is reached. Although the chance of any complications is generally low, as with all surgical procedures, there is an element of risk including failure to get benefit or pain aggravation. Allergic reactions to the steroid or any of the medications are uncommon, the injection may cause an infection or bleeding, perineal organ trauma or nerve damage is extremely rare.