Abstract: Objective To report a new clinical therapeutic technique,anococcygeal nerves destruction under CT guidance,in treating malignancy associated perineal pain after fecal and urinary diversion surgery,and evaluate the analgesic efficacy of this technique. Methods Three cases of late stage of malignancy associated perineal pain with artificial anourethral fistula have been involved in this study.The pain scored higher than 5 for all the three patients even they took more than 200 mg OxyContin per day.CT guided anococcygeal nerves destruction was performed when no contraindication to cavitas subarachnoidealis penetration was found.Coronal CT scan was performed to L4-S1 vertebrae,5 mm thick.The best penetrating spot for needle puncture was determined.After Local anesthesia,a #7 lumbar puncture needle was used to enter the cavitas subarachnoidealis through the intervertebral space between L5 and S1.When good cerebrospinal fluid circulation was confirmed,1.2 ml 5% phenol glycerin (1 ml 6% phenol glycerin plus 0.2 ml 30% iohexol) was slowly injected at the rate of 1 ml/min.The distribution of the physic liquor has been confirmed from another CT scanning,and 3D reconstruction.The patients kept their position for another 30 min after the puncture needle was removed,and was then sent to the wards.During the transportation and the first 6 h after,the patients need to keep sitting posture.The patients were monitored for vital signs during the treatment and for the first 12 h.Then they were tested for analgesic area using needle punching,and receiving follow up calls after discharge. Results The 3D reconstruction after surgery showed in all 3 cases,that the injected physic liquor was located in the terminal cistern,and the upper bound of the physic liquor located below the L5 vertebrae.After surgery,all patients lost their sensation at perineal area,and felt no pain even punched to bleed.Perineal pain was all gone.All the patients had the same,not affected muscle strength and sensation of their two lower limbs as that before the surgery.2 cases were followed up until death (survival durations were 9 months and 15 months);another case is still going on(4 months after surgery),all with no recurrent perineal pain. Conclusion Anococcygeal nerves destruction under CT guidance is a novel,safe,efficacious strategy in treating malignancy associated perineal pain,especially for those patients with terminal cancer and received fecal and urinary diversion surgery.