The impact of urodynamic parameters on the upper tracts of spinal cord injured men who void reflexly.

Few studies have evaluated which urodynamic parameters impact the upper urinary tracts in men with complete spinal cord injuries (SCI) who void reflexly. Previous studies focused primarily on voiding pressures. This study investigated the effects of bladder wall compliance, opening pressure, maximum detrusor voiding pressure, duration of the uninhibited contraction, cystometric bladder capacity and post-void residual on vesicoureteral reflux and stasis of the upper tracts. Urodynamic studies, cystograms and renal scans of 84 consecutive men with complete SCI who void reflexly were evaluated. Of the 84 patients (168 renal units), 71 men (142 renal units) had normal upper tracts, four patients (four renal units) had vesicoureteral reflux and nine patients (15 renal units--12 bilateral, three unilateral) had upper urinary tract stasis. There was no statistical difference between those with reflux and those without reflux with regards to any urodynamic parameter evaluated. When comparing those with and without upper urinary tract stasis, the only statistically significant difference in urodynamic parameters was the duration of bladder contraction. The mean duration of the uninhibited contraction in the non-stasis group was 113.7 seconds +/- 84 seconds (1.9 minutes +/- 1.4 minutes). The mean duration of the uninhibited contraction in the stasis group was 236.4 seconds +/- 139.1 seconds (3.9 minutes +/- 2.3 minutes, p = 0.0098). In summary, the duration of bladder contraction, which reflects both detrusor and sphincter function, was found to be an important variable in those with upper tract stasis. This should be considered when evaluating and treating men with complete SCI who void reflexly.