Dilatation of the urethra (tube from the urinary bladder to the outside) using size graduated dilators is one method of enlarging it to make urine flow out easier. It is more commonly used as a treatment in males than females because their longer urethra is more subject to stricture due to scarring from trauma or infection. It is still sometimes used in women although less frequently than it used to be.
There are two main reasons that the urethra is dilated. One is to relieve painful urination caused when the urethra is constricted and the bladder muscle is contracting during the act of voiding. This causes painful urination since the internal bladder pressure remains high for a longer time than normal because of obstruction to outflow. The second reason for urethral dilatation is to avoid chronic bladder infections and reflux of urine into the ureters and kidneys if the pressure inside the bladder is high as that can lead to permanent kidney damage. Its use is confined to urethral syndrome, urethral stricture and sometimes detrusor sphincter dysynergia.
Narrowing of the urethra may be due to involuntary contraction of the external or internal urethral sphincter muscles, external compression or irritation of the urethra by Skenes gland infection, urethral diverticula, scarring of the intrinsic muscle or epithelium of the urethra due to past trauma, surgery, or infection.
Alternative treatments available are drugs that relax smooth muscle (decreasing the contraction of the external urethral sphincter), drugs called alpha receptor blockers (relax internal urethral sphincter muscle), antibiotics (to treat Skenes gland infections), removal of urethral diverticula, etc. If all of these have been tried or taken into account then intrinsic urethral stricture may be the cause and dilatations may be the needed therapy.
Please discuss all this with your urologist and then decide.