The fact that you can’t urinate before the stone is about to fall may be caused by blockage of the ureter, bladder stones and other factors. 1. Ureteral blockage: the stone may fall into the ureter narrower place caused by the blockage, thus causing urinary obstruction, appearing before the stone is about to fall feel unable to pull the urine situation. 2. Bladder stones: In the process of urination, stones block the urethral orifice, causing bladder outlet obstruction, resulting in the urine stored in the bladder can not be discharged from the body in a timely manner, there will be a stone is about to fall before feeling unable to urinate, and will be accompanied by a sense of pain. If you feel unable to urinate, you should go to the hospital in time, do ultrasound and other related examinations, to clarify the cause of the disease under the guidance of the doctor for treatment.