SJ Lim, et al / Ganglion Impar Block With Botulinum Toxin Type A 67 Fig. 1. Lateral view of the ganglion impar after contrast injection. Fig. 2. AP view of the ganglion impar after contrast injection. has seven categories, such as activities associated with family/home responsibilities, recreation, social activities, occupation, sexual behaviors, self-care, and life-support activities, and scores are given with a scale ranging from 0 (no disability) to 10 (total disability). According to the PDI, scores were 10, 9, 10, 10, 10, 7, and 1, respectively, prior to treatment. Following the third session of blockage of the ganglion impar using BoNT-A, the PDI scores were greatly improved to 2, 2, 2, 2, 4, 3, and 0, respectively. These results indicate that the patient's condition had clearly improved. Currently, the patient has had a sat- isfactory outcome and is receiving follow-up observation. DISCUSSION 　　The etiology for CPP may include benign causes, such as chronic prostatitis and chronic proctitis, as well as ma- lignant causes, such as carcinoma of the pelvic organs. Infrequently, the cause of pain may be idiopathic. Chronic perineal pain is difficult to treat. The ganglion impar is a solitary retroperitoneal structure at the level of the sacro- coccygeal junction and it marks the termination of the paravertebral sympathetic chain [1,4]. The ganglion impar receives the nerve fibers from the sympathetic and para- sympathetic nervous system, which are present in the lumbar and sacral regions, and it is responsible for the distribution of sympathetic nerve fibers in the organs around the pelvis or reproductive organs [1,4]. The sym- pathetic nervous system is associated with myriads of pain syndromes. A blockage of the sympathetic nerve fibers has therefore been used to alleviate pain [1]. A ganglion impar block can be used to treat acute or chronic perineal pain [1,4]. In addition, blockage of the ganglion impar has been used extensively to treat anal or perianal sweating, rectal tenesmoid pain, and coccygodynia [1-3]. There exist vari- ous methods to block the ganglion impar, such as local anesthetics, concomitant use of local anesthetics and ste- roids, alcohol or phenol, and neurolysis by radiofrequency ablation [4]. 　　We performed blockage of the ganglion impar using BoNT-A. Botulinum toxin is a potent neurotoxin which is extracted from the exotoxin of Clostridium botulinum , which proliferates in contaminated foods and triggers the occurrence of food poisoning. Immunologically, there are seven types of antigens. Of these, types A and B have been used to treat human diseases [6]. BoNT-A binds to the presynaptic nerve endings and blocks the secretion of acetylcholine, thus causing a flaccid muscle paralysis. This chemodenervation transiently occurs, and while minimizing the systemic side effects, it persistently reduces or abol- ishes the activities of muscles, sweat glands, or muscles of contraction for several months [6]. Accordingly, the use of BoNT-A is effective in treating diseases associated with an excessive contraction of the muscles, including stra- bismus, blepharospasm, unilateral blepharospasm, and abnormal muscle tension in the neck [5]. Attempts have