Natural-fill urodynamics in chronically catheterized patients with spinal-cord injury

Objective To determine whether an indwelling catheter on free drainage prov ides a constantly low intravesical pressure in patients with a neuropathic bladder. Patients and methods Thirty patients with complete spinal-cord injury (SCI) whose bladders were managed exclusively with an indwelling catheter were a ssessed urodynamically using natural-fill urodynamics (ambulatory monitorin g) while their catheters were left on free drainage. Their upper urinary tr acts Mere assessed using plain X-rays and ultrasonography. Results Detrusor contractions causing intravesical pressure rises of >40cmH (2)O for up to 4.5 min were observed in II patients. Renal scarring was obs erved in nine patients: of these, six were in the group with contractions o f >40 cmH(2)O. whereas only five of 21 patients with normal kidneys had suc h pressure rises, Conclusion An indwelling catheter on free drainage is no guarantee of a con stantly low intravesical pressure. This study provides evidence to suggest that there is an association between phasic bladder contractions which occu r despite catheter drainage and upper urinary tract damage in permanently c atheterized patients with SCI.