Due to the small capacity bladder seen with neurogenic detrusor overactivity, and the potential for high bladder pressures leading to reflux, hydronephrosis, and kidney damage, and due to the potential for the contractions and small volumes to cause incontinence, the goals of therapy are to: 1) enhance bladder volume while lowering bladder filling pressures, and 2) to empty the bladder regularly in a low pressure voiding manner, usually with intermittent catheterization in people with an intact external sphincter, or external drainage in people that have had a procedure to physically or chemically obliterate the external sphincter. Methods to enhance bladder volumes will be discussed first. Note that this pertains to people usually on concomitant intermittent catheterization for drainage. Occasionally the volume enhancing treatments below will be used in combination with an indwelling catheter to avoid leakage around the catheter.