Bladder hypocompliance in the spinal cord injury population

To determine the incidence and effects of low bladder compliance on the upper urinary tracts in spinal cord injury patients, we evaluated the last 254 patients during a 3-year period who underwent a complete urodynamic study, along with an excretory urogram and/or renal ultrasound. Compliance was determined at 100 cc volume. A compliance number of 20 or less was considered low. Of the 254 patients 43 (17 per cent) had low compliant bladders by our definition. Hydronephrosis was present in 56 of the 84 renal units (64 per cent) and reflux was present in 39 (46 per cent). These results are in sharp contrast to the normal compliant group in which 21 per cent of 418 renal units had hydronephrosis and only 6 per cent had reflux. Of the 254 patients over-all 44 had lower motor neuron lesions as determined by no bulbocavernosus reflex as well as a denervated external sphincter; 22 of these 44 patients (50 per cent) had low compliant bladders. Conversely, among the 210 patients with suprasacral lesions only 21 (10 per cent) had low compliant bladders. In conclusion, the development of a low compliant bladder in spinal cord injury patients is not an uncommon event and places the upper urinary tracts at great risk. All attempts must be directed toward maintaining low detrusor pressures, and these patients must have adequate and frequent followup evaluation.