Inability to urinate is clinically known as urinary retention. There are two types of urinary retention, the first is acute urinary retention and the second is chronic urinary retention. Acute urinary retention is more common in patients with prostate hyperplasia who use atropine or drink a lot of alcohol and experience acute urinary retention; and in patients undergoing surgery who have urinary catheters inserted during the surgery and removed after the surgery and experience difficulty urinating and urinary retention. There are two types of causes of chronic urinary retention, the first is bladder outlet obstruction, such as urethral stenosis, prostate hyperplasia, bladder neck contracture patients, for these patients can be urethral dilatation, prostate electrocautery and other surgical treatments, to relieve the problem of bladder outlet obstruction. The second category is bladder function. Bladder problems include weak bladder muscle contraction, which can be treated with drugs to increase muscle contraction, and neuropathy of the nerves that innervate the bladder muscle contraction, for which the current treatment that can be tried is electrical stimulation of the sacral nerve.