1. In the treatment of erectile dysfunction (ED) – Men who have difficulty achieving an erection naturally due to causes such as age, diabetes, heart disease, or after prostate surgery.
   
2. During prostate cancer surgery rehabilitation – After prostate cancer surgery, it can be difficult to get an erection. Using an erection pump can help restore or support erectile function during the recovery process. Also helps maintain penis length.
   
3. To improve blood flow to the penis – Regular use of the pump can help improve blood circulation to the penis, which can contribute to better erectile function in the long term.
   
4. For temporary use – Some men use the erection pump occasionally to temporarily achieve an erection for sexual activity.
   
5. In Peyronie's disease - An erection pump can in certain cases help improve erectile function and reduce symptoms of Peyronie's disease .

Studies have shown that using a penis pump after prostate surgery does help maintain penis length.

In a study of 28 men, they were randomly assigned to receive a penis pump after nerve-sparing radical prostatectomy. Men in group 1 used the penis pump for 10 minutes a day for 5 months without an erection ring. Men in group 2 did not.
After three months, penile length had decreased by about 2 centimeters in men in group 2, but penile length was preserved in all men in group 1. After 12 months, only 2 of the 17 men in group 1 had a decrease in penile length of 2 centimeters or more compared to 5 of the 11 men in group 2.
Based on these findings, the researchers concluded that a penis pump helps maintain penile length within one month of use after radical prostatectomy. (Kohler 2007)

Another study of 42 men who had good sex lives before undergoing nerve-sparing radical prostatectomy showed a similar picture. The day after the men had their catheters removed, they began using a penis pump daily for 90 days. Thirty-seven men used the pump more than 50 percent of the 90 days, and only one of those men had a decrease in penis length of 1.0 centimeter or more.
When you compare these results with previous research, in which 48 percent of men experienced a significant reduction in penile length after prostatectomy, it appears that using a penis pump shortly after surgery is an effective way to maintain penile length. (Dalkin 2007)