**6.11 Pressure-flow studies**

Pressure-flow studies can differentiate between patients with a low Qmax secondary to obstruction and those whose low Qmax is caused by a decompensated or neurogenic bladder. They are most useful for distinguishing between bladder outlet obstruction and impaired detrusor contractility.

#### **6.12 Urethrocystoscopy**

Urethrocystoscopy should not be done routinely but is optional during later evaluation if invasive treatment is strongly considered (McConnell, Barry et al. 1994). Nevertheless, it is a useful preoperative procedure to plan the most appropriate approach. This investigation can confirm causes of outflow obstruction while eliminating intravesical abnormalities.
