[Background and aims]　In general, the indication of the ganglion impar block is considered to be the anal pain and the perineal pain. We experienced accidentally that the ganglion impar block performed for the anal pain was effective for the pain caused by pubic bone metastasis. Furthermore, we went for this block for the pain caused by pubic bone metastasis, they were effective.
[Methods]　The ganglion impar block were performed for 4 cancer patients,
all with cancer pain caused by pubic bone metastasis. The ganglion impar block with 3ml of 1%mepivacaine were performed at first. After successful good effects with local analgesic were obtain, neurolytic block were performed, by two times of radiofrequency thermocoagulation (at 90 degrees Celsius for 180 seconds) and injection of 3ml of absolute alcohol.
 [Results] All were female cancer patient from 58 years old to 72 years old. In three patients, NRS pain score were decreased, from mean NRS of 9.3(9/10-10/10) to mean NRS of 1.6(0/10-3/10).　One patient obtained analgesic effect which was reduced the frequency for rescue dosage, from five times per day to one time per day.  
[Conclusions] The ganglion impar block may provide a good analgesic effect on pain caused by the pubic bone metastasis.

The effect of ganglion impar block on cancer pain caused by pubic bone metastasis: report of 4cases