66 Korean J Pain Vol. 23, No. 1, 2010 eases, such as various types of headaches, lower lumbar pain, myofascial pain syndrome, and complex regional pain syndrome (CRPS), suggesting that the analgesic effect of BoNT-A has other mechanisms than the secondary effect due to muscle relaxation [6-8]. In a patient with perineal pain who did not have a satisfactory treatment outcome despite the use of drug therapy and other various types of nerve block, we achieved successful reduction of pain following blockage of the ganglion impar with the use of BoNT-A. Herein we report our case with a review of the literature. CASE REPORT 　　A 40-year-old man sought evaluation of a 4-year- history of perianal and perineal pain, including the testes and penis. In this patient, there was no notable history of trauma or disease. On MRI and CT scans, which included the abdomen and pelvis, there were normal findings. At the time of admission, the patient had a visual analog scale (VAS) of 8/10. The patient had the persistent presence of pain, which was characterized as bursting and explosive. Due to the presence of pain, the patient could not assume a sitting position for more than 5 minutes. The patient also stated that he could not perform work or household chores. Four years before the initial onset of pain, the patient had been working as aresearch staff in the US. At the time, the patient sought evaluation in a urology department un- der the assumption that the condition originated from the prostate gland. Following evaluation, the patient was con- sidered normal without a discernible etiology for the pain. The patient was therefore transferred to a pain clinic, where the patient was given oral medications (gabapetin 1,800 mg/day and methadone) in an outpatient setting. The patient also received superior hypogastric, caudal, and T12-L1 epidural blocks. However, these procedures had no effect in reducing the pain. In early February 2007, the patient sought evaluation in an outpatient clinic in the US due to aggravation of the pain in a lying position, and un- derwent blockage of the ganglion impar; the VAS de- creased from 8/10 to 4/10. Because the effect was sus- tained for approximately 1 day, the patient could not am- bulate for 2 months. During this period, the patient re- mained in a lying position. Thereafter, the patient under- went blockage of the ganglion impar on two occasions. Following this, the pain decreased to a VAS of 4/10. When the pain was severe, however, it was a VAS of 8/10. Every 3 months, the patient underwent blockage of the ganglion impar 4 times with the use of steroids 40 mg each, 4 times. In September 2008, the patient returned to Korea. At the time of his initial outpatient visit, the patient was recommended to undergo the blockage of the ganglion im- par by radiofrequency ablation. A diagnostic blockage was first performed using 0.5% bupivacaine 2 ml because the patient was concerned about the destruction of the nerve ganglion. The patient was monitored clinically, and 3 months later, the VAS of 8/10 had decreased to 5/10. Approximately 1 week later, however, the pain recurred with a VAS of 7-8/10. The severity of pain was not sig- nificantly different from the pain which existed prior to treatment. The patient was therefore motivated to have blockage of the ganglion impar using BoNT-A. For block- age of the ganglion impar, the patient was placed in a prone position. A subcutaneous infiltration was performed in the superior area of the anococcygeal ligament. This area was chosen as a puncture point. Using a C-shaped image intensifier, a 22 G, 10 cm block needle in which the terminal part was bent at an angle of 30 degrees was ad- vanced to a distance of 6 cm. Thus, attempts were made at the sacrococcygeal junction to reach the anterior surface. Following infusion of 2 ml of contrast media, the lateral and anterior-posterior views were evaluated (Fig. 1, 2). Based on the spread pattern of the contrast media, the infusion was performed with a concomitant use of 0.5% bupivacaine 1 ml and BoNT-A 80 U. The VAS of 7-8/10 decreased to 3/10, but the VAS increased to 5/10 two months following the blockage. Accordingly, with the use of BoNT-A, 2 months following the blockage, the gan- glion impar was blocked using 0.5% bupivacaine 2 ml and BoNT-A 100 U. When the patient underwent blockage us- ing BoNT-A again, the VAS decreased to 2/10 and this was maintained for 6 months. The patient perceived the pres- ence of perineal pain (a VAS of 5/10) during the sexual in- tercourse, which led to the third session of blockage of the ganglion impar at the same dose, which diminished the VAS to 2/10. At present, 3 months following the last treat- ment, other than perineal pain (a VAS of 4/10), the patient has had no problems in performing activities of daily living and work, including sitting and walking. The patient has maintained a VAS of 2/10. To evaluate the degree of dis- ability due to chronic pain during activities of daily living, a pain disability index (PDI) [9] was administered. The PDI