How we can find if spermatic cord are damaged during hydrocele surgery ?? my son 5years old had an operation for comunication hydrocele in both sides

Not before puberty: Damage to spermatic cords is unlikely if surgery was performed by surgical expert, especially if s/he is pediatric urologist or surgeon. U could review the operation report to see if note made of cuting vas during surgery. Or check pathology report of hydrocele specimen if it was sent for ?portion of vas. Otherwise you would need to wait till after puberty 2C if sperm present in ejaculated semen.