Ameda K, Steele G S, Sullivan M P, Stember D, Yalla S V
Division of Urology, Brockton/West Roxbury Department of Veterans Affairs Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
J Urol. 1998 Aug;160(2):482-6.
Recent studies suggest that detrusor contraction duration increases with bladder outlet obstruction and correlates with the American Urological Association (AUA) symptom index. Since the detrusor contraction duration may also depend on detrusor contractility and bladder volume, its use alone in characterizing bladder outlet obstruction is debatable. Therefore, we studied the relationship between detrusor contraction duration and bladder outlet obstruction, bladder capacity, detrusor contractility and symptoms to determine whether detrusor contraction duration is a useful parameter for characterizing bladder outlet obstruction in men with lower urinary tract symptoms.
Pressure-flow studies were performed in men with lower urinary tract symptoms. Bladder outlet obstruction was defined as passive urethral resistance relation greater than grade II and contractility was determined from Schäfer's nomogram. Detrusor contraction duration was defined as the contraction time elapsed between the first rise in detrusor pressure from baseline to the time at which detrusor pressure returned to baseline at the end of voiding. AUA symptom index was attained from each patient and categorized as mild (0 to 7), moderate (8 to 19) and severe (20 to 35).
Detrusor contraction duration was determined from 58 consecutive pressure-flow studies. This parameter was not significantly different among 23 patients with mild (116.7+/-34.0 seconds), 15 with moderate (102.7+/-61.9 seconds) and 9 with severe (89.2+/-44.4 seconds) AUA symptom index scores. AUA symptom index, as well as irritative and obstructive scores did not significantly correlate with detrusor contraction duration. Detrusor pressure at maximal flow was weakly correlated with detrusor contraction duration (r=0.322, p=0.014). However, detrusor contraction duration in 27 obstructed patients (111.6+/-53.7 seconds) was not significantly different from that of 31 nonobstructed patients (91.5+/-41.5 seconds) and it did not increase with the severity of bladder outlet obstruction. Detrusor contraction duration in 40 patients with good contractility (94.3+/-49.2 seconds) was significantly lower than in 18 patients with poor contractility (115.5+/-43.3 seconds). Detrusor contraction duration was significantly lower in nonobstructed patients with good contractility (72.0+/-21.7 seconds) compared with either nonobstructed patients with poor contractility (118.4+/-47.7 seconds) or obstructed patients with good contractility (112.5+/-58.0 seconds). There was no difference in detrusor contraction duration between nonobstructed patients with poor contractility and obstructed patients with good contractility. Multiple regression analysis showed that detrusor contraction duration can be best predicted by a combination of detrusor pressure at maximal flow, bladder capacity and contractility (r=0.576).
Our study showed that detrusor contraction duration cannot distinguish patients with from those without bladder outlet obstruction, and it does not correlate with the severity of symptoms. Since our results also showed that detrusor contraction duration depends on several factors related to detrusor and outlet function, it cannot be used as a reliable parameter to diagnose bladder outlet obstruction.
近期研究表明，逼尿肌收缩持续时间随膀胱出口梗阻而增加，且与美国泌尿外科学会（AUA）症状指数相关。由于逼尿肌收缩持续时间可能还取决于逼尿肌收缩力和膀胱容量，因此仅用其来表征膀胱出口梗阻存在争议。因此，我们研究了逼尿肌收缩持续时间与膀胱出口梗阻、膀胱容量、逼尿肌收缩力及症状之间的关系，以确定逼尿肌收缩持续时间是否是表征下尿路症状男性膀胱出口梗阻的有用参数。
对有下尿路症状的男性进行压力 - 流率研究。膀胱出口梗阻定义为被动尿道阻力关系大于Ⅱ级，收缩力根据施费尔列线图确定。逼尿肌收缩持续时间定义为从逼尿肌压力从基线首次上升到排尿结束时逼尿肌压力恢复到基线的收缩时间。从每位患者处获取AUA症状指数，并分为轻度（0至7）、中度（8至19）和重度（20至35）。
从58项连续的压力 - 流率研究中确定了逼尿肌收缩持续时间。该参数在23例AUA症状指数评分为轻度（116.7±34.0秒）、15例中度（102.7±61.9秒）和9例重度（89.2±44.4秒）的患者中无显著差异。AUA症状指数以及刺激症状和梗阻症状评分与逼尿肌收缩持续时间均无显著相关性。最大尿流率时的逼尿肌压力与逼尿肌收缩持续时间呈弱相关（r = 0.322，p = 0.014）。然而，27例梗阻患者的逼尿肌收缩持续时间（111.6±53.7秒）与31例非梗阻患者的逼尿肌收缩持续时间（91.5±41.5秒）无显著差异，且未随膀胱出口梗阻的严重程度增加。40例收缩力良好患者的逼尿肌收缩持续时间（94.3±49.2秒）显著低于18例收缩力较差患者的逼尿肌收缩持续时间（115.5±43.3秒）。与收缩力较差的非梗阻患者（118.4±47.7秒）或收缩力良好的梗阻患者（112.5±58.0秒）相比，收缩力良好的非梗阻患者的逼尿肌收缩持续时间显著更低。收缩力较差的非梗阻患者与收缩力良好的梗阻患者之间的逼尿肌收缩持续时间无差异。多元回归分析表明，最大尿流率时的逼尿肌压力、膀胱容量和收缩力的组合能最好地预测逼尿肌收缩持续时间（r = 0.576）。
我们的研究表明，逼尿肌收缩持续时间无法区分有无膀胱出口梗阻的患者，且与症状严重程度无关。由于我们的结果还表明逼尿肌收缩持续时间取决于与逼尿肌和出口功能相关的几个因素，因此它不能用作诊断膀胱出口梗阻的可靠参数。
