Hi,
Thanks for your question.
After going through your question, I can understand your concern.
Urinary bladder diverticulum develop due to forced uncoordinated contraction of urinary bladder muscles.
This type of contractions occur in response to some obstruction to flow of urine from bladder that is bladder out let obstruction.
There may be obstruction due to
enlarged prostate or problems in urethra.
CT scan and
Ultrasonography may detect enlarged prostate but MCU and
cystoscopy can detect problem in urethra.
Urologist has bypassed the obstruction by inserting catheter.
His Urologist is in better position to tell level of obstruction.
There is likely possibility of correction of obstruction with medicines only that's why Urologist has told that there is no requirement for surgery at present.
You have already consulted Urologist (who is the best doctor for treating this type of problem) , follow his advice.
Hope this helps you, if so do vote as helpful.