Patient: female, 27 years old, previously in good health. in March 2010, she fell from seasickness and vomiting to shock and landed on her left hip. Upon awakening, she developed a headache and mild pain in her buttocks. A few days later stiffness in the lower back unable to bend, spastic pain in the caudal spine, positive straight leg raise and normal muscle strength. The headache disappeared after neurology infusion (Micropol and dexamethasone) treatment, but the lumbar region remained stiff and the pain in the caudal spine increased when moving. After going home to work after half a month of bed rest, he found that he could not sit, stand or walk for a long time and had pain in his right buttock and the back of his thigh, which disappeared when he lay down. He was diagnosed as lumbosacral contusion and myofasciitis by the orthopedic hospital, and was hospitalized for more than one month with conservative treatment such as acupuncture and short wave. Later, he was diagnosed as lumbosacral myofasciitis in Sichuan Huaxi pain department, and was hospitalized for 2 weeks and treated with epidural nerve block. One week later, the condition recurred, and he still could not sit, stand or walk for a long time. The current symptoms are lower back pain, lumbosacral pain, feeling that there are 2 meridians on both sides of the caudal vertebrae have been pulling pain, especially the right side of the buttocks, has been pulling to the bottom of the buttocks, walking for a long time the right side of the rear leg pain, can not sit for a long time to stand, lying down symptoms disappear. Now the urine and stool are normal, straight leg raise is negative, no perineal pain condition, right leg muscles are mildly atrophied. oswestry score: 32 points. In the last visit to the orthopedic department of Sichuan Provincial People’s Hospital, the doctor judged that the pain was caused by a sacral canal cyst compressing the nerve according to MRI. Could you tell me if the condition is caused by a sacral canal cyst? How can I treat it? Thank you! Wu Wei, Department of Neurosurgery, General Hospital of Nanjing Military Region: From the medical history, the patient has a history of trauma and the pain is sudden, which is not quite consistent with the painful course of sacral canal cyst. The sacral cyst is a congenital disease, and there are many fistulas with the lower end of the dural sac. The combination of partial cyst excision + tipped sacrospinous flap filling + microscopic closure of fistula is a relatively good method, which can effectively prevent recurrence. Intraoperative perfect electrophysiological monitoring can prevent additional injury to the medical marginal nerve. The patient is recommended for surgical treatment.