In recent years, with the increase in the number of patients with urinary stones, we often encounter patients who forget to remove the double “J” tube (also called “pig tail” tube) after stone surgery for various reasons. This situation often makes follow-up treatment difficult. Here, we will introduce the dangers of late or no removal of the double “J” tube. 1. Why should I have a double “J” tube after stone surgery? Stone surgery often produces a large amount of stone debris, if the double “J” tube is not placed, there will be “mud and sand”, blocking the ureter, and even cause “stone street”, resulting in When the double “J” tube is placed, the stone debris will be discharged along the gap next to the double “J” tube. One of the reasons for placing the double “J” tube is to facilitate stone drainage and to prevent “stone streets”. On the other hand, surgery involving the ureter often causes ureteral edema, and some stones are prone to inflammation and may cause ureteral stenosis after long-term irritation of the ureter. 2.What kind of material is the double “J” tube made of? The early double “J” tubes were made of rubber, which lacked histocompatibility, and then scientists improved them by making them made of silicone, which improved histocompatibility, reduced irritation to the ureter, and extended the placement time. With the development of material engineering, many double “J” tubes are now made of polymeric material with a special coating on the surface, which slightly irritates the ureter, and the smooth surface also prevents urine salt deposits from forming stones. 3.Why do I need to remove the double “J” tube? Although the material of double “J” tube is being improved gradually with the rapid change of materials, the double “J” tube is still equivalent to a foreign object for human body. Since urine is obviously corrosive, it will erode the double “J” tube over time, and some of the early double “J” tubes have been reported to have fracture. On the other hand, after the surface coating of the double “J” tube is destroyed, a large amount of salt contained in the urine will adhere to it, gradually forming crystals and stones, which will cause serious irritation to the surrounding tissues, and even worse, a large number of stones will be formed, which will cause the inability to pull out. 4.What are the consequences of not removing the double “J” tube on time? In reality, due to various reasons, many patients fail to remove the double “J” tube on time, which causes many difficulties in the follow-up treatment. In clinical practice, we have seen patients who have not had their double “J” tubes removed for 1, 2 or 4 years after surgery, and after examination, a large number of attached stones were found to have formed and the double “J” tubes were completely blocked, resulting in hydronephrosis, which could not be removed by conventional means. 5.What should I pay attention to after placing the double “J” tube? Since the placement of double “J” tube is a routine treatment after stone surgery, we should understand and face it correctly. After the placement of double “J” tube, most patients will have different degrees of discomfort, mainly in the form of back pain when holding urine, painful urination at the end of urination, frequent feeling of wanting to urinate, and intermittent hematuria when moving, all of which are related to the stimulation of double “J” tube. It is recommended that during the period when the double “J” tube is not removed, patients should drink more water, avoid excessive holding of urine, avoid strenuous exercise and deep bending, and if necessary, carry out symptomatic treatment. On the other hand, patients and their family members must review regularly, keep in mind the maximum duration of the double “J” tube, remove it at the right time, and contact the doctor in charge if there are any problems.