小児下部尿路通過障害と潜在性神経因性膀胱

Abstract

As urodynamic investigations for the lower urinary tract, simultaneous recordings of intravesical and urethral pressure, and electromyographies of bulbo- and ischiocavernosus muscles have been performed through the bladder resting-filling and voiding phases, revealing the high incidence of outlet disorders in children with pyuria, microhematuria or vesical symptoms.Normally urethral pressure is stable during the bladder resting-filling phase, but in cases of hypertonic bladder with uninhibited detrusor contraction, urethral pressure is unstable and showes sharp waves, and in accordance with normalization of cystometrogram, urethral pressure is stablized. However, in half of the cases of hypotonic or flaccid bladder, urethral pressure becomes unstable and fluctuates in irregular waves, which differs apparently from those of hypertonic bladder.Peak pressure is usually recorded at the external sphincteric urethra, and sharply decreases immediately before detrusor contraction in normal cases. But this dynamic change during prevoiding phase is easily altered, when outlet disorders are present. The urethral pressure curves during prevoiding phase could be divided simply into three patterns: normal decrease, no change, and increase. When recorded as normal decrease, the external sphincter may be expected to be electrically silent. When recorded as abnormal increase, the external sphincter shows electrically pathological discharges, which means external sphincter spasm; or oppositely very low electrical activities. Although the external sphincter spasmus is not proved electrically in these cases, unstable urethral pressure during the bladder resting-filling phase is recorded, and defective opening of the bladder neck is observed on micturating cystourethrogram. When recorded as no change, organic urethral stenosis, mainly Lyon's Ring, could be proved in more than half of the cases.To simplify the various roentgenographic shapes of bladder outlet disorders, micturating cystourethrograms are divided into five patterns based on diameter of the posterior urethra and the relative degree of bladder neck opening, and matched to the simultaneous recordings of pressure and electromyographies. The results are partly mentioned above, and each pattern is corresponded well to the urodynamic data, especially to the urethral pressure.Although the bladder outlet disorders are well analyzed in general, but we still need more new clinical methodes for the full understanding of the bladder neck dysfunction.