The odd ganglion (anglion impar) is the terminal junction of the lumbar sympathetic nerve chain. The odd ganglion receives sympathetic and parasympathetic fibers from the lumbosacral region and provides sympathetic innervation to the pelvic organs and genital sites. Its location is anterior to the medico-caudal coalition, and a nerve block (disruption) is possible at this level. Indications for odd ganglion block (disruption): Odd ganglion block (disruption) is commonly used for the treatment and evaluation of sympathetic-mediated pain in the lower abdomen, perineum, recto-anal region and genitalia to relieve lower abdominal and perineal pain, especially cancer pain, that is ineffective with conservative treatment and effective with ganglion block. 1.Treatment of pain of malignant tumors for which conservative treatment is ineffective, such as postoperative anal pain of rectal cancer, pain caused by infiltration and compression of nerves in the pelvic cavity of colon, rectum, cervical and ovarian cancers, etc.; 2.Treatment of pain secondary to endometriosis, reflex sympathetic dystrophy pain, post-traumatic anal pain, refractory anal pain, post-traumatic refractory perineal pain after trauma, pain from radiation enteritis, and persistent pain after hemorrhoidectomy; 3. To evaluate lower abdominal and perineal pain on an anatomical basis, as well as to provide prognostic information for ganglion disruption.