Background: Coccydynia is defined as pain in and around the coccyx. It has numerous causes and multiple contributing factors, ranging from obesity to childbirth trauma. It may arise as a consequence to soft tissue, bony, or even visceral pathology (e.g., spinal cord convergence, pressure on the coccyx, or an atypical pain referral pattern). In patients who do not respond to conservative treatment for coccydynia, ganglion impar block can be used as a good alternative to pain relief. However, the factors associated with successful responses to ganglion impar block for coccydynia are not well understood.

Methods: From January 2013 to December 2017, we performed a retrospective review of 192 cases with coccydynia patients who underwent ganglion impar blocks. Patients were considered successful responders if they showed a decrease of more than 50% or 4 points on the numerical rating scale. Logistic regression analysis was performed to determine the factors associated with successful responses to this surgical procedure.

Results: After ganglion impar block, 36 (18.75%) of patients were considered successful responders. Univariate logistic regression analysis showed that coccydynia related with cancer was independently associated with successful responses after this surgical procedure (odds ratio = 3.236; 95% confidence interval = 1.368 s study is a retrospective study, the follow-up period varies from patient to patient. The different definition of successful response may have led to different results. In addition, the correct method of assessing functional status, which might have affected the outcome, could not be used in this study
Conclusion: These results suggest that ganglion impar block can be more effective on cancer-related coccydynia than other causes.