The choice of open surgery as well as minimally invasive surgery for repeat nephrectomy needs to be judged according to the severity of the disease. If the condition is mild, minimally invasive surgery can be chosen; if the condition is severe, open surgery is needed. 1. Mild condition: the duplicate kidney itself only has mild hydronephrosis and infection symptoms, which can be recovered by partial surgical resection, and can be treated by minimally invasive surgery. 2. Severe condition: the duplicate kidney is more obvious, causing serious urinary obstruction and infection, and need to do ureteral bladder reimplantation surgery, most of them need to choose open surgery for treatment. Duplicate kidneys, accompanied by obvious urinary obstruction and renal pain, fever and other symptoms need to be timely medical observation, diagnosis of the condition, under the guidance of the clinician for standardized treatment, to avoid delays in the condition.