Relief of intractable perineal pain by coccygeal nerve block in anterior sacrococcygeal ligament after surgery for rectal cancer.

Intractable perineal pain often appears in the anal region following abdominoperineal resection for the treatment of rectal cancer. In such cases, a subarachnoid block or transsacral block is generally used to control pain. However, these procedures sometimes cause complications such as dysuria or sensory paralysis of the pudendum. A new method of pain control is presented herein using absolute alcohol as a neurolytic agent to relieve localized perineal pain through a coccygeal nerve block in the anterior sacrococcygeal ligament. Five cadavers were necropsied to localize the coccygeal nerve. A loop consisting of S4, S5, and Co was found to exist in the space surrounded by the anterior surface of the coccygeal bone and the anterior sacrococcygeal ligament. Absolute alcohol was injected into this space. It is essential that the neurolytic agent remain localized in this space to avoid complications and to successfully block perineal pain. In all patients, we found that this method was extremely effective in blocking localized perineal pain without any complications.