4 month old diagnosed with (1) left testicle atrophy (2) right testicle hydrocele with normal blood flow during ultrasound examination and report from radiologist and pediatrics. can surgery be performed for left testicle atrophy for 4 month old?

Yes & no.: You must have the child seen by a pediatric urologist. Only that kind of specialist can be of help.I would waste no time in getting an appointment. Get copies of the imaging studies that were done to take with you.

Yes, but not urgent: Usually, babies' testicles can move around. Sometimes a testis is above the scrotum at birth, and comes down later, or it is in the scrotum at birth, and gets pulled up above the scrotum a little later. Testis hydrocoele (water around a testis) is not that uncommon, and many times the water goes away on its own. A pediatric urologist can take an initial look anytime and do surgery later if needed.

Depends: Depends on what you mean by surgery for atrophy. If you are correct, the kid has one normal testis with a little extra fluid around it, and one that likely lost its blood flow and withered. It is unlikely to be salvageable. Some would remove it later & replace it with a prosthesis.You only need one good one for fertility.You need to meet soon with a pedi urologist and develop a long term plan.

Need to observe: First you must find the cause of left testicular atrophy--is it due to developmental or vascular incident going back to intrauterine life or even a torsion ( then have to fix on the right side ). Once it atrophies, there is no surgery. Possible it may be just small testicle--with growth, size may increase. Speak to his doctor & if necessary get second opinion from a pediatric surgeon.

ConsultPediatricUrol: We can not advice you on this site about surgery without examining the baby and getting the story right I suggest you consult a Pediatric Urologist after discussing with baby's Pediatrician