1. Kwon M, Altin M, Duenas H, Alev L. The role of descending inhibitory pathways on chronic pain modulation and clinical implications. Pain Pract. 2014;14(7):656-667. doi:10.1111/papr.12145
2. Li SQ, Jiang L, Cui LG, Jia DL. Clinical efficacy of ultrasound-guided pulsed radiofrequency combined with ganglion impar block for treatment of perineal pain. World J Clin Cases. 2021;9(9):2153-2159. doi: 10.12998/wjcc.v9.i9.2153
3. Gunduz OH, Sencan S, Kenis-Coskun O. Pain relief due to transsacrococcygeal ganglion impar block in chronic coccygodynia: a pilot study. Pain Med. 2015;16(7):1278-1281. doi:10.1111/pme.12752
4. Toshniwal GR. Transsacrococcygeal approach to ganglion impar block for management of chronic perineal pain: a prospective observational study. Pain Physician. 2007;10(5):661.
5. Lee SH, Yang M, Won HS, Kim YD. Coccydynia: anatomic origin and considerations regarding the effectiveness of injections for pain management. Korean J Pain. 2023;36(3):272-280. doi:10.3344/kjp.23175
6. Kao S-C, Lin C-S. Caudal epidural block: an updated review of anatomy and techniques. Biomed Res Int. 2017;2017:9217145. doi:10.1155/2017/ 9217145
7. Conn A, Buenaventura RM, Datta S, Abdi S, Diwan S. Systematic review of caudal epidural injections in the management of chronic low back pain. Pain Physician. 2009;12(1):109-135.
8. Kaya SS, Akcaboy EY, Celik S, et al. A comparative and retrospective study on the efficacy of caudal epidural steroid injection plus ganglion impar block versus ganglion impar block in patients with coccydynia. Ann Med Res. 2022;29(12):1413-1417.
9. Datir A, Connell D. CT-guided injection for ganglion impar blockade: a radiological approach to the management of coccydynia. Clin Radiol. 2010;65(1):21-25. doi:10.1016/j.crad.2009.08.007
10. Farrar JT, Young Jr JP, LaMoreaux L, Werth JL, Poole RM. Clinical importance of changes in chronic pain intensity measured on an 11-point numerical pain rating scale. Pain. 2001;94(2):149-158. doi:10. 1016/S0304-3959(01)00349-9
11. Dworkin RH, Turk DC, Wyrwich KW, et al. Interpreting the clinical importance of treatment outcomes in chronic pain clinical trials: IMMPACT recommendations. J Pain. 2008;9(2):105-121. doi:10.1016/j.jpain.2007.09.005
12. Govardhani Y, RamMohan G, Abhijith S, Savithri B. A comparative retrospective study of the efficacy of caudal epidural with manipulation versus ganglion impar block with manipulation in patients with coccydynia. Indian J Pain. 2021;35(1):42-45.
13. Buttaci CJ, Foye PM, Stitik TP. Poster board 56: coccydynia successfully treated with ganglion impar blocks: a case series. Am J Phys Med Rehabil. 2005;84(3):218.
14. Foye PM, Buttaci CJ, Stitik TP, Yonclas PP. Successful injection for coccyx pain. Am J Phys Med Rehabil. 2006;85(9):783-784. doi:10.1097/01.phm.0000233174.86070.63
15. Elkhashab Y, Ng A. A review of current treatment options for coccygodynia. Curr Pain Headache Rep. 2018;22(4):28. doi:10.1007/s11916-018-0683-7
16. Nagpal AS, Vu T-N, Gill B, et al. Systematic review of the effectiveness of caudal epidural steroid injections in the treatment of chronic low back or radicular pain. Interv Pain Med. 2022;1(4):100149. doi:10.1016/j.inpm. 2022.100149