Coccydynia, also called coccygodynia refers to pain in the coccyx region. The term was given by Simpson in 1859. However, the condition has been reported in the literature before that period too.
The coccyx is lowermost part of the spine and is also called tailbone. One can feel the lower end of the coccyx in the proximal part of the gluteal cleft [The groove between the buttocks]. It is right there where a tail would be in animals.
Other names for the condition are tailbone pain or coccyx pain, coccygeal pain, coccyx pain, coccyaglia or tailbone pain.
Coccydynia is much more common in women than in men.
Coccydynia is rare, accounts for less than 1% of back pain conditions.
Anatomy of Coccyx
The word coccyx is derived from the Greek word for the beak of a cuckoo bird
The coccyx is the terminal portion of the spine and consists of 3-5 fused vertebrae. The largest one that articulates with sacrum through a rudimentary articular process called the coccygeal cornua [the other part is called the sacral cornua.]. The coccyx attaches the sacrum. The attachment could be a symphysis as a true synovial joint, There is very limited movement between the coccyx and the sacrum.
The coccyx represents a vestigial tail (so the term tailbone). The ventral side of the coccyx is slightly concave whereas the dorsal aspect is slightly convex.
The coccygeal ligament is the name given to the lower part of the filum terminale and it inserts onto this first segment.
Anteriorly, the coccyx is bordered by the levator ani muscle and the sacrococcygeal ligament.
Anterior to posterior, the lateral edges serve as insertion sites for the coccygeal muscles, the sacrospinous ligament, the sacrotuberous ligament, and fibers of the gluteus maximus muscle.
The iliococcygeus muscle tendon inserts onto the tip of the coccyx.
The attached ligaments and muscles support the pelvic floor and also contribute to voluntary bowel control.
Types of Coccyx
Postacchini and Massobrio described four orientations of coccyx wherein anterior angulation of the coccyx may be a normal variant.
The coccyx is curved slightly forward, with its apex pointing caudally. It is the most common type and found in 15% of the people.
The coccyx is curved more markedly anteriorly, with its apex pointing straight forward. This type is found in approximately 15% of people.
The coccyx is sharply angulated forward between the first and second or the second and third segments. It occurs in 5% of the people.
The coccyx is subluxed anteriorly at the level of the sacrococcygeal joint or at the level of the first or second intercoccygeal joints. This type is found in about 10%.
Patients with a type II-IV coccyx are more prone to develop idiopathic coccygodynia than those with a type I configuration.
Causes of Coccydynia
Coccydynia occurs if there is an injury or excess pressure on the area causing the bones to move beyond their normal very limited range of motion. This results in inflammation and localized pain. Ligaments, the vestigial and bones of the coccyx can source of pain. Infection of coccyx can also lead to pain.
A fall on the coccyx causes injury to ligaments or bone. It is the most common cause of coccydynia.
During delivery, the baby’s head passes over the top of the coccyx, and the pressure created against the coccyx can sometimes result in injury to the coccyx structures.
Horse riding and sitting on a hard surface for long periods of time may cause the onset of coccyx pain.
Tumor or Infection
Rarely, coccydynia is due to a tumor or infection in the coccyx area that puts pressure on the coccyx.
It is not clearly understood which portions of the anatomy can cause coccyx pain. In many cases, the exact cause of the pain is not known (called idiopathic coccydynia), and in these cases, the symptoms are managed.
Clinical Presentation of Coccydynia
A localized pain over the coccyx which is worse with sitting is the classic presentation of coccydynia. The pain will usually worsen with prolonged sitting, leaning back in seated position, worse with prolonged sitting, leaning back while seated and moving from sitting to standing position.
The patient may complain of pain during sexual intercourse or defecation.
There could be a presence of significant recent trauma that resulted in acute pain or the pain may have begun insidiously with no clear inciting factor.
The patient should be enquired about sitting tolerance [Time of sitting can be tolerated before the pain forces to change position].
The patient should be enquired about cushions tried, medications taken or interventions done previous to the visit.
In females, any events around the childbirth become important to note.
On examination, the coccyx would be tender to touch. If the coccyx is not tender, consider the possibility of the pain referred from other sites as well.
The rectal examination would allow checking for coccyx mobility [sacrococcygeal joint, normal appx 13 degrees.]
The examination includes lumbar spine examination and other probable causes of pain like ischial bursae, sacroiliac joints, lumbosacral facet joints, and lumbosacral or gluteal muscles.
The skin over the spine should be examined for sinus [pilonidal sinus] and any other notable deformity.
- Lumbar pain
Not required for diagnosis except to rule out infection.
X-ray is an initial investigation especially in patients with a history of trauma. AP and lateral view are most commonly done. Coned-down view of coccyx gives better exposure.
X-rays may reveal
- Abnormal sacrococcygeal curvature
- Sacrococcygeal or intracoccygeal dislocation.
Dynamic stress films [sitting and standing positions] can detect the sagittal rotation of the pelvis.
CT of Coccyxis rarely indicated for objective evidence of fractures in medicolegal cases.
MRI coccyx is usually not required but can be included in the lumbosacral MRI if the pain is thought to originate from anatomic structures located more superiorly within the spine.
CT/MRI can be useful in intrapelvic pathologies.
In a typical case, all imaging studies will be negative.
Injections for Localization of Pain
The injections of local anesthetic with without steroid can be used for diagnosis of pain source whether it is coccyx or some other structure. If injection to the coccyx results in pain relief, most likely the coccyx is responsible for pain.
These injections can also help identify patients who might benefit from a coccygectomy when contemplated.
Treatment of Coccydynia
Most of the patients of coccydynia can be treated by conservative treatment.
Posture and Avoidance
The patient is educated about correct sitting posture and avoid leaning back while sitting. Activities that worsen pain such as prolonged sitting, bike riding, horse riding etc should be avoided.
Local heat/Cold Application
The patient can apply local heat or cold [both have been found to be equally effective]. The best way to do this is by Sitz bath where water is filled in the tub or Sitz kit [commercially available] and patient immerses perineum and hip.
Cushions help to relieve the pressure of the coccyx.
Modified wedge-shaped cushions or coccygeal cushions which can relieve the pressure on the coccyx when the patient sits are recommended. These are available over the counter.
Nonsteroidal anti-inflammatory drugs (NSAIDs) are used to relieve pain and inflammation.
Topical analgesic creams are also used and help to avoid side-effects of oral medications.
Pelvic Floor Physical therapy
Pelvic floor rehabilitation can be helpful for coccydynia that is associated with pelvic floor muscle spasms.
Tight, painful muscular structures such as the levator ani, coccygeus, or piriformis muscles are targeted. Myofascial release techniques may be used. Local modalities also may be helpful.
Pelvic floor physical therapy has been reported to be an effective treatment for chronic pain including those who have chronic coccydynia even after coccygectomy.
Manual manipulation and massage
This refers to intrarectal manipulation under anesthesia. Many authors have claimed it to be mildly effective through the clear evidence is lacking.
The ganglion impar is also called ganglion of Walther and is the unpaired terminal ganglion of the paravertebral sympathetic nervous system usually located anterior to the sacrococcygeal junction or near.
Hypersensitivity of the ganglion impar is thought to be responsible for persistent chronic pain which is sympathetically maintained.
Local injection of an anesthetic can effectively block the ganglion impar and thereby relieve coccyx pain.
Repeat ganglion impar blocks may be required and have been shown to provide additional benefit.
Steroid injections mixed with local anesthetics are given around the coccyx, usually at the sacrococcygeal junction or around the sacrococcygeal ligaments.
Repeat injections may be required.
Nerve ablation [uses heat or cold or current to destroy nerve fibers] is reserved for patients for chronic pains where none of the treatment has relieved pain [before coccygectomy].
The site of pathology would depend on the specific site of coccygeal pathology. A diagnostic injection of local anesthetic prior to ablation is performed to ascertain the site of pain.
If one sitting of ablation does not provide relief, it may be repeated.
Some patients may have a recurrence of pain after months or years due to collateral reinnervation. A repeat ablation may be performed in such cases.
Surgical treatment for coccydynia is partial or complete coccygectomy [removal of coccyx].
Surgical procedures for the treatment of coccydynia are used only as a last resort. The procedure has been associated with a high complication rate.
It is recommended that non-surgical options must be exhausted before considering surgery.
Transcutaneous electrical nerve stimulation or TENS could be of benefit in selected cases.
If a non-organic cause is suspected, psychotherapy is indicated.
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- Buttaci CJ, Foye PM, Stitik TP, et al. Coccydynia successfully treated with ganglion impar blocks: a case series. Am J Phys Med Rehabil. Mar 2005. 84(3):218.
- Gopal H, McCrory C. Coccygodynia treated by pulsed radiofrequency treatment to the Ganglion of Impar: a case series. J Back Musculoskelet Rehabil. 2014 Feb 20.
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