I am interested in the scientific basis of this practice and your opinion in its effectiveness. I could not find anything. I also wonder what you use, how you use, how long you use? And the reason for every step.
Hypospadias surgery is difficult and it can cause too much stressful problem for the family and the child. As a surgeon we cannot guarantee the family for excellent results.
I have not a routine practice i.e., diazepam to prevent penile erection after hypospadias surgery. Maybe you might be right, the erection can be responsible for all complications such as dehiscence or urethral fistula in hypospadias surgery.