STUDY DESIGN: A prospective pilot study with independent assessment and a 2-year follow-up period was conducted. OBJECTIVES: To compare and assess the efficacy of three manual coccydynia treatments, and to identify factors predictive of a good outcome. SUMMARY OF BACKGROUND DATA: Various manual medicine treatments have been described in the literature. In an open study, the addition of manipulation to injection treatment produced a 25% increase in satisfactory results. Dynamic radiographs of the coccyx allow breakdown of coccydynia into four etiologic groups based on coccygeal mobility: luxation, hypermobility, immobility, and normal mobility. These groups may respond differently to manual treatments. METHODS: The patients were randomized into three groups, each of which received three to four sessions of a different treatment: levator anus massage, joint mobilization, or mild levator stretch. Assessment with a visual analog scale was performed by an independent observer at 7 days, 30 days, 6 months, and 2 years. RESULTS: The results of the manual treatments were satisfactory for 25.7% of the cases at 6 months, and for 24.3% of the cases at 2 years. The results varied with the cause of the coccydynia. The patients with an immobile coccyx had the poorest results, whereas those with a normally mobile coccyx fared the best. The patients with luxation or hypermobility had results somewhere between these two rates. Levator anus massage and stretch were more effective than joint mobilization, which worked only for patients with a normally mobile coccyx. Pain when patients stood up from sitting and excessive levator tone were associated with a good outcome. However, none of the results was significant because of the low success rate associated with manual treatment. CONCLUSIONS: There is a need for a placebo-controlled study to establish conclusively whether manual treatments are effective. This placebo must be an external treatment. A sample size of 190 patients would be required for 80% confidence in detecting a difference.

STUDY DESIGN: A total of 208 consecutive coccydynia patients were examined with the same clinical and radiologic protocol. OBJECTIVES: To study radiographic coccygeal lesions in the sitting position, to elucidate the influence of body mass index on the different lesions, and to establish the effect of coccygeal trauma. SUMMARY OF BACKGROUND DATA: A protocol comparing standing radiographs and radiographs subsequently taken in the painful sitting position in coccydynia patients and in controls has shown two culprit lesions: posterior luxation and hypermobility. Obesity and a history of trauma have been identified as risk factors for luxation. METHODS: Dynamic radiographs were obtained. The body mass index was compared with the coccygeal angle of incidence, sagittal rotation of the pelvis when sitting down, and the presence and time of previous trauma. The patients with the newly described lesions were examined after an anesthetic block under fluoroscopic guidance. RESULTS: Two new coccygeal lesions are described (anterior luxation and spicules). Obesity was found to be a risk factor. The body mass index determines the way a subject sits down, and lesion patterns were different in obese, normal-weight, and thin patients (posterior luxation: 51%, 15.2%, 3.7%; hypermobility: 26.5%, 30.3%, 14.8%; spicules: 2%, 15.9%, 29.6%; normal: 16.3%, 32.6%, 48.1%, respectively; P < 0.0001). Trauma affected the type of lesion only if it was recent (<1 month before the onset of coccydynia), in which case the instability rate increased from 55.6% to 77.1%. Backward-moving coccyges were at greatest risk of trauma. CONCLUSIONS: This protocol allows identification of the culprit lesion in 69.2% of cases. The body mass index determines the causative lesion, as does trauma sustained within the month preceding the onset of the pain.
 

Coccygectomy is a controversial operation. Some authors have reported good results, but others advise against the procedure. The criteria for selection are ill-defined. We describe a study to validate an objective criterion for patient selection, namely radiological instability of the coccyx as judged by intermittent subluxation or hypermobility seen on lateral dynamic radiographs when sitting. We enrolled prospectively 37 patients with chronic pain because of coccygeal instability unrelieved by conservative treatment who were not involved in litigation. The operation was performed by the same surgeon. Patients were followed up for a minimum of two years after coccygectomy, with independent assessment at two years. There were 23 excellent, 11 good and three poor results. The mean time to definitive improvement was four to eight months. Coccygectomy gave good results in this group of patients.

PURPOSE An abnormally high rate of coccydynia following lumbar fusion (CLF) has been reported, but not explained. We tried to define the risk and to establish why lumbar fusion should be followed by coccydynia. BACKGROUND DATA A protocol for the investigation of the coccyx has been described, involving lateral films with the patient standing and then sitting in the painful position. This investigation showed two major causes (48.8% of cases) of coccydynia seen in the sitting position only: posterior luxation of the coccyx (reduced when standing), and hypermobility in flexion. These two causes were seen in different patients, as shown by a recent series of 208 cases (Table). In the other cases, patients had normal coccygeal mobility when sitting, with the coccyx usually flexed. This series showed that the body mass index (BMI) was related to certain angles that reflected the way patients were sitting down and positioning their coccyx. A high BMI was associated with low degree of pelvic rotation when sitting down, and with a high coccygeal angle of incidence; and vice versa. The type of lesion was a function of the angle of incidence (Table). The risk of post-traumatic coccydynia was a function of the degree of pelvic rotation. With a high degree of rotation, the coccyx tucks itself in under the pelvis on sitting down, and is thus protected. With a low degree of pelvic rotation, the coccyx remains posterior and vertical, and is thus exposed to external trauma and to repetitive sitting stress microtrauma. METHODS Of 380 patients with chronic coccydynia examined since 1992, 11 (2.9%) had CLF. In nine cases, the condition had appeared within 3 months after surgery, without any associated low-back pain. In two cases, coccygodynia was made markedly worse by fusion. The results of the patients’ radiological examination were compared with those of a control group of 208 patients without CLF. Statistical Analysis Proportions were compared using the chi squared test. Comparisons of several means were performed using ANOVA or t-tests, as appropriate. A significance level of p<0.05 was used. RESULTS Frequency According to health authority estimates, the rate of lumbar fusions in France is 0.05% of the adult population. Thus, the relative risk of CLF is 58 (p<0.0001). None of the CLF patients had a history of local trauma (vs 33.6% of the controls, p=0.02). Fusion is not, therefore, associated with a higher rate of a fall on the coccyx. Lesions Nine patients (82%) had hypermobility; one patient (9%) had posterior luxation; and one (9%) had normal mobility; this pattern was different from the one found in the control group, where the respective rates were 27.6%, 21.2%, and 51.2% (p<0.0001). BMI and angles In the CLF group, the BMI (22.8±3.5) and the coccygeal angle of incidence (21°±25) did not differ greatly from the values seen in the controls with the same lesions (24.4±4.4, p=0.23; and 24.8°+20, p=0.17, respectively). However, the degree of pelvic rotation was very much lower in the CLF group (24.4°±7.6 vs 42.6°±13.2, p=0.01), showing that lumbopelvic rotation had been blocked by fusion. CONCLUSION CLF patients constitute a homogeneous group with the following features: no history of causative trauma; major limitation of sagittal pelvic rotation; and predominance of hypermobility as the cause of coccygeal pain. Lumbar fusion increases the risk of coccydynia, since it limits pelvic rotation on sitting down. This means that (1) the coccyx will not tuck itself completely under the pelvis in the sitting position, and will therefore be exposed to repetitive sitting stress microtrauma; and (2) the stiff lumbosacral junction will transfer the sitting-down stress onto the coccyx. The low angle of coccygeal incidence further exposes the coccyx to hyperflexion in case of microtrauma.

STUDY DESIGN: Ninety-one patients with common coccygodynia and 47 control subjects prospectively underwent dynamic radiographic imagery. OBJECTIVES: To standardize the radiologic protocol to better define normal and abnormal mobility of the coccyx, and to study clinical parameters useful in classifying and differentiating the lesions. SUMMARY OF BACKGROUND DATA: In a previous study, comparison of films taken in the sitting and standing positions allowed to individualize two distinct coccygeal lesions: luxation and hypermobility. Measurement technique was precise and reproducible, but the control group was not pain-free. No specific clinical features were described. METHODS: Standing films were made first. Control subjects were healthy volunteers. The following items were recorded: presence of an initial traumatic event, elapsed time before investigation, body mass index, presence of an acute pain when passing from sitting to standing, effect of intradiscal steroid injection, and angle of the coccyx with respect to the seat. RESULTS: Hypermobility was defined as a flexion of more than 25 degrees, luxation by displacement of more than 25% of the coccyx. The base angle is a good predictor of the direction in which the coccyx moves when sitting. In the "luxation" group, a history of initial trauma, a shorter clinical course, pain when standing up, increased body mass index, and satisfactory results with intradiscal injection were found more frequently than in the "normal" group. The "hypermobility" group had characteristics between these two groups. CONCLUSION: Common coccygodynia is associated in 48.4% of patients with a luxation or hypermobility of the coccyx. A distinct clinical presentation was found in individuals with luxation of the coccyx.

STUDY DESIGN. The authors hypothesized that the source of coccygodynia was a lesion of the coccygeal disc. OBJECTIVES. This study analyzed the motion of the painful coccyx in the sitting position as compared with the lateral decubitus in a patient and a control group and reported the first results of coccygeal discography (dynamic study). SUMMARY OF BACKGROUND DATA. Coccygodynia are usually attributed to soft tissue injuries or psychologic disturbances. No previous study has assessed the coccygeal discs as a source of pain. METHODS. Fifty-one patients with coccygodynia and 51 controls sustained a dynamic study. Coccygeal mobility was documented by superimposing graph paper with a double reading. The accuracy of the measurement was +/- 2.6 degrees intra- and interobserver variations 15.3 and 12.5%. This dynamic study was followed by coccygeal discography in the patient group. RESULTS. An abnormal motion (luxation or hypermobility) of the coccyx that occurred in the sitting position and spontaneously was reducible when placed in the lateral decubitus position was found in 25 patients. Such lesions could be responsible for the pain because no similar findings were seen in the controls and coccygeal discography was positive in these cases. Of the 26 patients with a normal dynamic study, coccygeal discography, using a combination of provocation and anesthetization, was positive in 15 of 21. CONCLUSIONS. Common coccygeal pain could come from the coccygeal disc in approximately 70% of cases.

In coccygodynia, pain is most severe in the sitting position. This prompted a study comparing lateral roentgenograms of the coccyx taken with the patient lying on the side with films taken in the (painful) sitting position. In this prospective study, eight of 30 patients had posterior subdislocation of the coccyx which caused pain and was visible only on the films taken in the sitting position.