TURP is performed under general or spinal (local anaesthetic injected in the spine to numb up from the waist down) anaesthesia and involves the passing of a sheath and telescope down the urethra or waterpipe to the prostate. Electricity flows through a half moon loop of wire, which is drawn through the prostate, allowing the resection of tissue, in chippings, creating a wide cavity through the length of the prostate, maximally relieving obstruction with the aim of improving bothersome urinary symptoms. The length of the procedure is determined by how much tissue needs to be removed, i.e. the size of the prostate, but will typically take an hour or so. Once any bleeding is controlled, the patient is left with a postoperative urinary catheter (tube draining the bladder) and usually bladder irrigation is employed in the first instance to reduce the risk of any blood clots forming that may block the catheter. This irrigation is slowed, then stopped over time, before the catheter is removed and typically one or two nights in hospital are required. With the new bipolar systems, however, control of bleeding can be such that the irrigation is removed that same day and the patient may go home with the catheter, to return a few days later for its removal.