Whether surgery is needed for prostate enlargement depends on symptoms, bladder function, and complications rather than just post-void residual urine. A post-void volume of 126 cc is moderately elevated. It may indicate incomplete bladder emptying, but some men can be managed with medications and lifestyle changes if symptoms are mild. Since you are on Dynapres (likely for blood pressure), your doctor will consider your overall health, urinary symptoms (like frequency, urgency, weak stream), and risk of complications such as urinary retention, infections, or kidney issues before recommending surgery. It is important to consult a urologist, who may recommend further tests such as a flow study, ultrasound, or cystoscopy to determine the most appropriate treatment, which may include continued medication or surgical intervention if necessary.