In the clinic, for the following several situations before the need to play closed needle: 1, inflammation is too heavy. A site has some limited, sterile inflammation, through the conventional conservative treatment effect is poor, inflammation is still relatively heavy, this time you can do closed treatment, rapid relief of local sterile inflammation. 2, local pain, and the patient is difficult to tolerate. After the occurrence of injury or inflammation, patients will be more or less accompanied by pain, generally preferred non-steroidal drugs to reduce inflammation and pain. However, in clinical practice, there are many cases after such treatment, the pain is not significantly relieved, and some patients have poor tolerance of pain, feel unbearable pain, this time can be closed injection of the painful parts to quickly stop pain. 3, for athletes to use closed needle. Before an athlete competes, there may be local inflammation or minor injuries, and closed injections can be used to achieve the effect of temporary localized painlessness. But currently, as anti-doping screening is becoming more and more stringent, the frequency of using closed needles is becoming less and less.