抄録
男子23例(正常群8例、神経囚性膀胱のDSD(+)群7例、DSD(-)群8例)を対象に、膀胱空虚時の神経節放電の3要素の定量分析と、排尿の全過程での外尿道括約筋筋電図のFFT分析を行った。膀胱空虚時の神経節放電の3要素(位相数、振幅、持続時間)は3群間で有意の差を認めなかった。また膀胱内圧曲線のパターンによる差も認められなかった。したがって膀胱空虚時の神経節放電の3要素のみの分析では神経因性膀胱の障害部位の診断には不十分と考えられた。正常群のFFT分析の結果、RestとFDVで150〜220Hzで-20dB以下のpowerを示し、MPFは100Hz前後であった。MDVでは高周波成分が著明に増加し、MPFも75%の症例で150Hz以上に増加した。Voidでは神経筋放電の消失に従いpowerも消失した。
In 23 male patients, the electrical activity of external urethral sphincter muscle was sampled before examination of cystometry (Rest), at first desire to void (FDV), maximum desire to void (MDV) and during urination (Void) by means of electromyography (EMG). Sampling time of each event was 2400 msec. The electrical activity was amplified with a lower limiting frequency of 20 Hz and an upper limiting frequency of 10000 Hz, and recorded on magneto-optical desk. Spectra were obtained using a Hamming window. The action potential of the muscle was quantitatively analyzed and power spectrum of the needle EMGs were analyzed from the magneto-optical disk by a spectrum analyzer using fast Fourier transformation (FFT,Sande-Tukey method). From each power spectrum, mean power frequency (MPF) was obtained from a calculator connected to the spectrum analyzer. Twenty three patients were divided into three groups as follows: 8 patients without any neurological abnormality (normal group), 7 patients with neurogenic bladder showing detrusorsphincter-dyssynergia (DSD+group) and 8 patients with neurogenic bladder witbout detrusor-sphincter-dyssynergia (DSD-group). The results obtained were as follows: 1) The motor unit potentials at Rest had the mean amplitude of 210±59.4μV, 329.3±157.1μV and 177.6±132.8μV in normal group, DSD+group and DSD-group, respectively. The mean duration were 4.3±0.2 msec., 5.9±1.9msec, and 7.3±4.5msec., respectively. The mean phases were 2.8±0.6, 2.8±0.5 and 2.5±0.3, respectively. Statistically there was no difference in amplitude, duration and phase among three groups. 2) In normal group, the power over than-20dB was distributed from150 to 220Hz windows at Rest and FDV. The needle EMGs at MDV showed interference pattern and the power increased over-20dB in all windows. The power of high frequency area relatively increased. The action potential of the muscle disappeared during urination and the power also disappeared. The average MPF was 103Hz, 102Hz, 150Hz and 98Hz at Rest, FDV, MDV and Void, respectively. 3) In DSD+group, the needle EMGs showed intederence pattern in MDV and Void, and the power increased only in low frequency area. The average MPF was 104Hz, 105Hz, 114Hz and 120Hz at Rest, FDV, MDV and Void, respectively. 4) Because of damage to nerves, the action potential of the muscle was difficult to obtain from 3 patients of DSD-group, and the power was not demonstrated. 5) The distribution of frequency of interference pattern of the needle EMG is shifted toward higher frequencies in normal patients and toward lower frequencies in patients with neurogenic disorders (DSD+and DSD-groups). The MPF is decreased in neurogenic muscle compared with normal muscle.
