Coccydynia - could age, trauma and body mass index be independent prognostic factors for outcomes of intervention?

Introduction The aetiology of coccydynia can be multifactorial, with several associated factors such as obesity, female gender and low mood. The long-term results of operative interventions, such as manipulation under anaesthesia and coccygectomy are variable, ranging from 63-90%. Materials and methods Our aim was to identify whether age, trauma and body mass index (BMI) were independent prognostic factors in coccydynia treatment. All patients who presented to the Royal Derby Hospital with a primary diagnosis of coccydynia between January 2011 and January 2015 who had injections, manipulation under anaesthesia or coccygectomy were included. We used patient-reported satisfaction score as the primary outcome measure. We hypothesised that patients with preceding history of trauma and with high BMI (> 25) would be less satisfied. We divided patient BMI into four groups, following World Health Organization guidelines: group A (18.5-24.9), group B (25-29.9), group C (30-39.9) and group D (> 40). Results A total of 748 patients were diagnosed with coccydynia. Of these, 201 patients had 381 injections, 40 had 98 manipulations under anaesthesia and 9 had coccygectomy. Mean age was 46.4 years; 26% of patients had trauma to the coccyx. The mean time to follow-up was 7.3 months. We found a statistically significant difference (P = 0.03) between satisfaction scores in groups B and D. Patients who had trauma improved significantly (P = 0.04). The odds ratio calculation of coccygectomy and BMI revealed a higher risk of coccygectomy in Group A. Discussion This is the first study to establish BMI and trauma as independent prognostic factors for coccydynia treatment. Our hypothesis that patients with higher BMI would have lower satisfaction levels has been proven true.