Coccydynia (coccygodynia)

INTRODUCTION — Coccydynia (also referred to as coccygodynia or tailbone pain) is pain at the coccyx. Although coccydynia resolves in the majority of patients with supportive care, symptoms can persist for months or years and, in some patients, may become a life-long condition. Intractable coccydynia is relatively uncommon, but when it occurs it can dramatically decrease a patient's quality of life. This topic will provide an overview of coccydynia, including diagnosis and management.

ANATOMY — The coccyx is the lowest region of the vertebral spine, located inferior to the sacrum (figure 1). Typically, the lower coccyx curves anteriorly, into the pelvis (figure 2 and figure 3). The coccyx, along with the two ischial tuberosities, bears weight when a person is sitting, with an increased weight load on the coccyx when a person leans back, partly reclining, in the sitting position (figure 4).

The coccyx typically has three to five vertebral segments, with fibrocartilaginous joints between the sacrum and coccyx and between coccygeal vertebral bodies. These joints are comparable with those seen in higher intervertebral spaces but may be fused in the coccyx. Muscles and ligaments that insert on the sacrum and coccyx (including the levator ani and its component parts) support the pelvic floor and participate in voluntary control of the bowel.

PREVALENCE AND RISK FACTORS — The prevalence of coccydynia is unknown [1]. It most commonly occurs in adolescents and adults [2,3], although children are sometimes affected. Coccydynia is generally considered to be far less common than lumbosacral low back pain.

Coccydynia is five times more prevalent in females than males [1,3]. The higher prevalence is thought to be due to injuries that occur during childbirth as well as the coccyx being located more posteriorly in females (figure 3) and thus more susceptible to external trauma [4].

Obesity is a risk factor [5,6]. It is hypothesized that obesity may lead to coccydynia by changing the way people sit and/or by increasing the total weightbearing load.

ETIOLOGY — There are many etiologies for coccydynia, with the most common causes being related to trauma [6,7]. Some cases may be idiopathic [5].

●External direct trauma – A common cause of coccydynia is direct external trauma from a fall backwards into a sitting position, in which the coccyx is bruised, broken, or dislocated [1]. This may lead to inflammation and spasm of the surrounding muscles. As an example, a small case series documented coccydynia due to coccyx trauma secondary to the use of recreational water slides [8].

●Repetitive minor trauma – Coccydynia may also occur in the setting of prolonged sitting from repetitive minor trauma [1]. This occurs especially with poor posture, on a hard or ill-fitting surface (eg, during air or car travel), or on a narrow surface (eg, bicycle riding). This is also exacerbated by inflammation and muscle spasm.

●Injury during childbirth – Injury is caused by pressure exerted on the coccyx during childbirth (figure 5), especially during difficult delivery and with use of forceps [9,10]. In addition to the internal pelvic pressure on the coccyx while the baby is passing through the birth canal, there may also be external pressure from the body's semi-reclined position during the birth process, with pressure on the coccyx throughout the labor and delivery.

●Posterior bone spicules/coccyx bone spurs – Coccydynia may be caused by a spicule or small bony spur on the dorsal aspect of the lowest tip of the coccyx [5]. The bone spicule/spur irritates the coccygeal region when the patient is sitting; the bone spur may pinch the skin between the spur and the seating surface [7].

●Coccygeal instability – Both hyper- or hypomobility of the sacrococcygeal joint have been associated with coccydynia [1,6]. Coccygeal dynamic instability (excessive mobility at the coccygeal joints) is underappreciated and underdiagnosed, largely because sitting-versus-standing radiographs are rarely performed. (See 'Imaging' below.)

●Osteoarthritis – Osteoarthritis may contribute to coccydynia [1]. However, although such changes are commonly seen on radiographs (similar to findings on lumbar spine radiographs), it is important for the clinician to determine whether such imaging findings clinically cause or contribute to a given patient's symptoms. (See "Evaluation of low back pain in adults", section on 'Limited utility of imaging'.)

●Other – Somatization, particularly in the setting of known depression, has been reported as an etiology of coccydynia [1,7]. However, psychological etiologies are not more common in coccydynia than in other pain syndromes. (See "Somatic symptom disorder: Epidemiology and clinical presentation" and "Somatic symptom disorder: Assessment and diagnosis".)

Patients may have coccydynia from complex regional pain syndrome. However, these patients may not have the associated sensory changes, motor impairments, and autonomic symptoms. (See "Complex regional pain syndrome in adults: Pathogenesis, clinical manifestations, and diagnosis", section on 'Clinical manifestations'.)

Rare causes include infection, metastatic cancer, calcium crystal deposits in the sacrococcygeal and intercoccygeal joints, chordomas, benign notochordal cell tumors, avascular necrosis, arachnoiditis of the sacral nerves, glomus tumor, and precoccygeal dermoid cyst [1,7,11-14]. (See "Spinal cord tumors", section on 'Chordomas'.)

CLINICAL FEATURES

History — In patients with coccydynia, pain and tenderness are typically well-localized to the coccyx [1]. Patients complain of pain in the tailbone on sitting, especially when leaning back. Some patients have an abrupt increase in pain during the transition from sitting to standing. Patients may also complain of pain with defecation, sexual intercourse, and radiation of the pain to the floor of the pelvis due to muscle spasms.

When evaluating a patient, we ask about the location of the pain, exacerbating positions/precipitants, duration, severity, and any history of trauma. Asking the patient to point to the specific site of pain can usually distinguish coccyx pain from typical lumbosacral sources of low back pain [15]. We also assess for specific etiologies of coccydynia as well as other causes of pain in the same region by asking about:

●Pain associated with surrounding areas – Back, buttock, abdominal, rectal, or pelvic pain

●Symptoms of infection – Fever, chills, dysuria

●Symptoms of malignancy – Night sweats, weight loss, unexplained rectal or vaginal bleeding

●Symptoms of pelvic disease – Penile or vaginal discharge, bowel or bladder symptoms

Examination — In patients with isolated coccydynia, focal external palpation of the coccyx that reproduces pain symptoms but palpation of the surrounding area does not [1]. A focused external examination of the coccyx should reproduce the patient's pain and tenderness with focal external palpation and no surrounding erythema or swelling. In patients where the diagnosis is uncertain with external palpation, internal palpation of the coccyx via rectal examination can be helpful. The coccyx, grasped between the thumb and the inserted forefinger, is tender and painful on movement, while adjacent structures are unremarkable. Other components of the physical examination (eg, examination of the lumbosacral spine or pelvic exam) may be performed based upon concerns elicited from the history.

DIAGNOSIS

Clinical diagnosis — The diagnosis of coccydynia can be made upon history and physical examination. In patients with coccydynia, pain and tenderness are typically well-localized to the coccyx [1]. Patients complain of pain in the tailbone upon sitting, especially when leaning back. The diagnosis of coccydynia is confirmed by focal external palpation of the coccyx that reproduces the patient's symptoms locally without pain in the surrounding area [1]. If the diagnosis is uncertain based on external palpation, internal palpation of the coccyx via rectal examination can be helpful. (See 'History' above and 'Examination' above.)

Additional evaluation — Many patients do not need imaging. Patients with mild or short-lived symptoms may be managed without imaging studies. We obtain imaging for the following patients:

●Severe pain and history of blunt trauma – We obtain plain anterior-posterior and lateral radiographs in patients with severe pain and a history of blunt trauma to assess for fracture or dislocation. (See 'Management' below.)

●Symptoms concerning for infection or malignancy – We obtain imaging in patients with symptoms or physical examination findings that suggest an underlying infection (eg, osteomyelitis, soft tissue abscess) or malignancy (eg, chordoma, metastatic tumors). These patients include those with systemic symptoms (eg, fevers, chills, night sweats, unexplained weight loss), concerning symptoms of nearby organ systems (eg, unexplained rectal bleeding), or a concerning physical examination (eg, swelling, fistula, or discharge around the coccyx or pain that is not localized to the coccyx). The possibility of cancer is especially important to consider in patients with a history of known or suspected regional malignancy (eg, cancer of the prostate, cervix, uterus, ovaries, or colon).

We generally obtain magnetic resonance imaging (MRI) in these patients; however, other evaluation may be appropriate if there is concern for a specific malignancy (eg, colonoscopy for rectal bleeding to assess for colon cancer). When obtained, MRI should specifically include midline sagittal slices/images in both T1 (to show bony details) and T2 or short tau inversion recovery (STIR) images (to show fluid changes such as inflammation). (See "Clinical presentation, diagnosis, and staging of colorectal cancer", section on 'Diagnosis' and "Principles of magnetic resonance imaging".)

●Persistent symptoms – Patients with persistent symptoms (>2 months) should have imaging. (See 'Imaging' below.)

DIFFERENTIAL DIAGNOSIS — The differential diagnosis for coccydynia includes disorders affecting structures in the same region.

Pain may be referred to the coccyx from diseases of the spine. Spinal pathology, such as lumbar disc disease, may coexist with coccydynia, so clinicians should pay close attention to the patient's specific site of pain elicited during the history and identified on physical examination [7]. Spinal disease at the cervical, thoracic, or lumbosacral levels does not cause coccygeal tenderness to palpation, the hallmark of coccydynia. (See "Lumbar spinal stenosis: Pathophysiology, clinical features, and diagnosis".)

If symptoms and tenderness on physical examination seem more localized to the pelvic floor muscles rather than focal to the coccyx, disorders of the pelvic floor and pelvic organs (eg, prostatitis, pelvic inflammatory disease, levator ani syndrome, or other pelvic pain syndromes) should be considered. Patients with diseases of the pelvic organs will generally have pain that is not localized to the coccyx and have other accompanying symptoms. (See "Acute bacterial prostatitis" and "Pelvic inflammatory disease: Clinical manifestations and diagnosis" and "Acute pelvic pain in nonpregnant adult females: Evaluation" and "Chronic pelvic pain in nonpregnant adult females: Causes".)

Other etiologies to consider include pilonidal sinus infection and proctalgia fugax. Pilonidal sinus infection involves subcutaneous pain, redness, warmth, and swelling over the coccyx, often with a visible sinus and purulent drainage. Proctalgia fugax refers to sudden attacks of fleeting rectal pain without gross pathology. (See "Pilonidal disease" and "Proctalgia fugax".)

Sacral perineural cysts (eg, Tarlov cysts) are usually considered "incidental" radiologic findings that are not a source of symptoms, but in rare cases they may cause coccyx pain [16].

MANAGEMENT

Initial management — Patients found to have infection or malignancy should be treated accordingly. For other patients with acute coccydynia, we start with conservative management with protection, analgesics, and heat or ice rather than more invasive therapy [1]. Patients should also avoid exacerbating factors if possible (eg, certain sitting surfaces).

Most cases of coccydynia (90 percent) will resolve either without medical care or with conservative management [1]. Coccydynia associated with acute trauma is more likely to resolve than symptoms that develop insidiously and without obvious cause. Most patients can expect symptom resolution over weeks to months and should be managed conservatively for at least two months before considering other therapies.

●Protection – While it is not possible to put the injured part to complete rest, patients can protect their coccyx while sitting by leaning forward so that weight is mainly borne on the ischial tuberosities and posterior upper thighs (figure 4). "Donut" cushions (pillows with a hole in the center) or "wedge" cushions (with a wedge-shaped section cut out of the back) distribute weight away from the coccyx. In our experience, wedge cushions tend to be much more beneficial than donut cushions. Many styles of cushions are sold in pharmacies or on the internet. Patients can also make a wedge cushion by cutting a wedge out of a two- to four-inch foam rubber cushion.

●Analgesics – We start patients on nonsteroidal antiinflammatory drugs (NSAIDs) for pain relief unless patients are diagnosed with an acute fracture. We avoid NSAIDs in patients with acute fracture as there is some evidence to suggest that fracture healing may be impaired by NSAIDs. (See "Nonselective NSAIDs: Overview of adverse effects", section on 'Possible effect on fracture healing'.)

In patients who have contraindications for NSAIDs, acetaminophen may be used. Opioid analgesics or tramadol are options in patients with severe pain related to acute trauma and/or fracture.

There are no studies that have evaluated the effectiveness of analgesics in coccydynia [1]. However, as NSAIDs are used to treat back pain and osteoarthritis, they may be effective for coccydynia as well. (See "Treatment of acute low back pain", section on 'Initial therapy' and "Overview of the management of osteoarthritis", section on 'Overview of management'.)

●Heat or ice – Patients should try heat or cold based on their preference.

Intranasal calcitonin has been examined as an option for therapy in patients with acute fracture in small observational studies [17], but no randomized trials have evaluated this treatment.

Persistent symptoms — A minority of patients develop chronic coccydynia, defined as symptoms persisting for >2 months. Patients with persistent symptoms should be referred to a specialist with experience in managing coccydynia for comprehensive care.

Imaging — We obtain imaging in patients with persistent symptoms (eg, >2 months). We generally start with plain radiographs. If the patient has already had normal radiographs or the patient has developed symptoms concerning for infection or malignancy, we obtain magnetic resonance imaging (MRI). (See 'Additional evaluation' above.)

Coccygeal radiographs can evaluate for fractures, dislocations, hypermobility, bone spurs, and degenerative changes [1]. When plain radiographs are performed, patients should have both anterior-posterior and especially lateral radiographs. Specific types of radiographs are used to evaluate for particular etiologies of coccydynia:

●Sitting-versus-standing films (coccygeal hypermobility) – To evaluate for coccygeal hypermobility (dynamic instability), lateral radiographs are taken while standing (or supine) and while sitting in the most painful position. Seated radiographs are also called coccygeal stress views, due to the weightbearing stress upon the coccyx while sitting (figure 4). The alignment and angles of the coccygeal vertebral bodies while standing and sitting are compared to evaluate for excessive mobility. Coccygeal hypermobility is diagnosed when sitting causes the position of the coccyx to flex by ≥20 degrees, as compared with the coccyx position while supine or standing. Similarly, coccygeal hypermobility is also diagnosed if sitting causes listhesis (subluxation) of more than 25 percent of the coccygeal vertebral body, as compared with the coccyx position while supine or standing [5,18]. These seated images may not be available at all institutions, as many radiology technicians and radiologists are not familiar with this technique.

●Coned down lateral views (bone spurs) – To evaluate for distal coccygeal bone spurs, lateral radiographs specifically using coned-down views are especially useful. For coned-down views, the radiology technician attaches a collimator to the radiograph source to optimize the clarity of the coccygeal images obtained.

Local injection — For patients with persistent symptoms, we suggest management with a series of coccygeal injections containing local anesthetic or local anesthetic plus glucocorticoid. Local injection may be most effective for patients with coccygeal instability or bone spurs. Ideally, prior to injection, an accurate anatomic diagnosis should be made via imaging.

Injections may be directed at the sacrococcygeal junction, individual coccygeal joints, a coccygeal bone spur, the caudal epidural space, or the ganglion impar. Injection of coccygeal structures, guided by fluoroscopy, with either local anesthetic or local anesthetic plus corticosteroids, relieves or alleviates symptoms in many patients [1,7,19].

Case series have found positive results from injection at the ganglion impar, a midline sympathetic ganglion located just anterior to the upper coccyx [20-24]. As an example, in a series of 22 patients with persistent coccydynia who failed to respond to initial conservative treatments, ganglion impar injection successfully provided >50 percent relief in 82 percent of patients, with a mean duration of relief of six months [22]. Among these patients, a repeat ganglion impar injection typically provided an even longer effect, with a median duration of relief of 17 months.

The addition of corticosteroids to local anesthetic may further enhance the efficacy of nerve blocks. As an example, in an observational study including over 70 patients with chronic coccydynia, ganglion impar block with local anesthetic plus corticosteroid decreased pain and improved depression at one and three months compared with local anesthetic alone [25].

A 2021 systematic review including seven observational studies and 189 patients with coccydynia assessed response to treatment with ganglion impar block (with local anesthetic plus glucocorticoid) or ganglion impar radiofrequency ablation [26]. Response rates were similar with both treatments, with just over 85 percent of patients reporting moderate improvement in symptoms at six months.

Other treatments — Many treatments have been advocated for persistent coccydynia, but the evidence of effectiveness is variable. Pelvic floor physical therapy and manipulation are adjunctive treatments that may be beneficial for specific patients.

●Pelvic floor physical therapy – Pelvic floor physical therapy is most helpful in patients with significant pain within the muscles, tendons, and ligaments of the pelvic floor [1]. These patients often report pain that is inferior and anterior to the coccyx, rather than pain that is strictly localized to the coccyx. They may also have other pelvic floor symptoms, such as pain during sex or difficulties with bowel or bladder function. A retrospective study of pelvic floor physical therapy in 79 patients with coccydynia found that 86 percent had a good outcome, defined as least a 40 percent improvement in average pain score, and 62 percent had an excellent outcome, defined as at least a 60 percent improvement in the average pain score [27]. (See "Myofascial pelvic pain syndrome in females: Pelvic floor physical therapy for management".)

●Manipulation – Manipulation may be most helpful in patients with pain from muscle spasms in proximity to the sacrococcygeal region [1]. However, in patients with coccygeal hypermobility, fractures, and bone spurs, manipulation may worsen symptoms. Manipulation via the rectum is done to massage muscles attached to the coccyx that might be in spasm and to mobilize fascia and the coccyx [28]. This may include levator ani massage/stretching.

In a randomized trial of 102 patients with chronic (>2 months) coccydynia, scores for pain and functional impact improved over the six months for both the manipulation and placebo groups. The group that received manipulation were more likely to improve compared with the placebo group (36 versus 20 percent), but neither group had a large improvement [29]. Also, manipulation was least likely to help those with coccygeal hypermobility, potentially due to mobilization treatment causing worsening of the hypermobility.

●Medications for chronic pain – Patients with persistent symptoms may respond to therapeutic regimens that are used for patients with chronic pain of any etiology. However, there are no studies on use of these medications in coccydynia. (See "Approach to the management of chronic non-cancer pain in adults".)

●Other – Interventions that have advocates but no evidence of effectiveness include ultrasound, short-wave diathermy, and transcutaneous nerve stimulation.

Intractable coccydynia — Surgical excision of the coccyx is generally a last resort reserved for patients with intractable coccydynia who have undergone a full trial of nonsurgical treatments without relief. Complete coccygectomy removes the coccyx at or just proximal to the sacrococcygeal junction, avoiding the rectum (which is immediately anterior), and ideally leaving the periosteum and ligamentous attachments intact. Partial coccygectomy leaves the upper coccygeal vertebral bone(s) in place.

Case series of patients undergoing coccygectomy report relief in most patients, although there is disagreement about the magnitude of effectiveness, perhaps due to patient selection [30-34]. A 2011 review of the surgical treatment of coccydynia excluding patients with malignancy found 24 articles, most retrospective case series, reporting on 671 patients [35]. Seventy-five percent were reported to have excellent/good outcomes. The complication rate was 11 percent, and complications were mostly infections but also included hematomas, delayed wound healing, and wound dehiscence. Subsequent studies have been consistent with the review. In a consecutive series of coccygectomies at an academic medical center in California, 26 of 61 patients were followed for a median follow-up of 37 months, with 85 percent reporting excellent/good outcomes [36]. In another prospective study, including 98 patients with chronic coccydynia who had failed conservative management, 70 percent had improvement in patient reported pain and disability at two years [37]. Thirty percent were classified as failures, including up to 6 percent with disability scores worse than presurgery. In the absence of a randomized trial, it is not possible to know the extent to which recovery was related to factors other than surgery.

SUMMARY AND RECOMMENDATIONS

●Coccydynia definition and risk factors – Coccydynia is pain in the coccyx. It is more common in females than males. Obesity is a risk factor. It is often related to trauma. (See 'Prevalence and risk factors' above and 'Etiology' above.)

●Diagnosis – Diagnosis can be made by history and physical examination. Pain and tenderness are typically well-localized to the coccyx, and symptoms are reproduced with direct pressure on the coccyx during a physical examination. Unless acute fracture, dislocation, infection, or malignancy is suspected, imaging is not immediately necessary for most patients with acute coccydynia. (See 'Diagnosis' above.)

●Conservative management for acute pain – For acute coccydynia (≤2 months) that is not caused by infection or malignancy, we start with conservative management rather than more invasive therapy. Conservative treatments include protection with wedge pillows, analgesics, and heat or cold applications. (See 'Management' above.)

Most patients can expect symptom resolution over weeks to months and should be managed conservatively for at least two months before more aggressive management is tried.

●Imaging and referral for persistent symptoms – Patients with persistent symptoms (>2 months) should be referred to a specialist with experience in managing coccydynia. We obtain imaging in these patients. (See 'Imaging' above.)

●Local injections for persistent symptoms – For patients with persistent coccydynia (>2 months), we suggest management with coccygeal injections containing local anesthetic or local anesthetic plus glucocorticoid (Grade 2C). (See 'Local injection' above.)

●Coccygectomy as treatment of last resort for intractable pain – We suggest that coccygectomy be performed only as a last resort for intractable cases (Grade 2C). Results of effectiveness from randomized trials are not available and there is a risk of serious complications, including infection and hematoma. (See 'Intractable coccydynia' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Robert H Fletcher, MD, MSc, who contributed to an earlier version of this topic review.