Coccygectomy for patients with chronic coccydynia: a prospective, observational study of 98 patients

The purpose of this prospective study was to evaluate the outcomes of coccygectomy for patients with chronic coccydynia.

Between 2007 and 2011, 98 patients underwent coccygectomy for chronic coccydynia. The patients were aged > 18 years, had coccygeal pain, local tenderness and a radiological abnormality, and had failed conservative management. Outcome measures were the Short Form 36 (SF-36), the Oswestry Disability Index (ODI) and a visual analogue scale (VAS) for pain. Secondary analysis compared the pre-operative features and the outcomes of patients with successful and failed treatment, two years post-operatively. The threshold for success was based on a minimum clinically important difference (MCID) on the ODI of 20 points. All other patients, including those lost to follow-up, were classified as failures.

There was significant improvement in all ten components of the SF-36 (p < 0.05), the ODI (23 points) and VAS (39 points) (p < 0.0001). A total of 69 patients (70.4%) met the designated MCID threshold for a successful outcome. The failure group consisted of 25 patients (25.5%) who did not reach the MCID and four (4.1%) who were lost to follow-up. Six patients (6.1%) in the failure group had ODI scores that were no better or worse than that pre-operatively. The patients in whom treatment failed had significantly worse pre-operative scores for the ODI (p = 0.04), VAS (p = 0.02) and on five of ten SF-36 components (p < 0.04). They also had a higher incidence of psychiatric disorders, pre-operative opiate use and more than three comorbidities.

Coccygectomy for chronic coccydynia results in significant improvement in patient-reported outcomes at two years. Failure is associated with certain pre-operative characteristics such as psychiatric illness, poor quality of life features, higher levels of pain, and use of opiates.