Urine retention, u/s shows mild prostatic enalrgement doctor prescribed tamsulin,and recommend surgury if no improvement.when is surgury needed?

Unclear: You have asked a difficult question. It all dependes on your symptoms as to retention or only slow stream. With mild enlargement , there is little to do at this time. It also depends on the response to the medication. Ask your doctor about a hormone blocker if appropriate such as avodart (dutasteride) This may be of some help Make sure you see a urologist.