Effects of Extracorporeal Shock Wave Therapy on Pain in Patients With Chronic Refractory Coccydynia: A Quasi-Experimental Study

BACKGROUND: Several nonsurgical and surgical treatment modalities are available for patients with chronic coccydynia, with controversial results. Extracorporeal shock wave therapy (ECSWT) is effective in the treatment of many musculoskeletal disorders; however, it has not been tested for chronic coccydynia. OBJECTIVES: We performed the current study to determine the effects of ECSWT on pain in patients with chronic coccydynia. PATIENTS AND METHODS: This quasi-interventional clinical study included 10 patients with chronic coccydynia without acute fracture. All the patients received ECSWT with a radial probe delivering 3,000 shock waves of 2 bar per session at 21 Hz frequency directed to the coccyx. Each patient received four sessions of ECSWT at one-week intervals. The pain severity was recorded according to the visual analog scale (VAS) at one, two, three, and four weeks after initiation of therapy. The VAS score was also evaluated at one and six months after ending the therapy. RESULTS: Most of the participants were women (90.0%), and the participants’ mean age was 39.1 ± 9.1 (ranging from 28 to 52) years. The VAS score did not decrease significantly seven months after therapy when compared to baseline (3.3 ± 3.6 vs. 7.3 ± 2.1; P = 0.011). However, the VAS score at two months (2.6 ± 2.9 vs. 7.3 ± 2.1; P = 0.007) and at four weeks (3.2 ± 2.8 vs. 7.3 ± 2.1; P = 0.007) significantly decreased when compared to baseline. The decrease in VAS scores was not persistent after cessation of the therapy. CONCLUSIONS: ECSWT is an effective modality in relieving the pain intensity in patients with refractory chronic coccydynia for the early period after intervention.