R318; R459.9; R311;
目的 探究内外括约肌失协同对下尿路器官组织应力和尿液流速的影响。方法 基于火棉胶切片对下尿路器官组织进行几何模型重建,并建立含有肌肉主动力的下尿路有限元模型；通过流-固耦合仿真,模拟排尿末期内外括约肌均正常收缩、均丧失主动力和单独丧失主动力四种情况下的组织应力和尿流速率变化。结果 内外括约肌正常收缩尿道应力变化和临床测得的尿道压力变化趋势相同。与正常收缩情况比较,内括约肌单独丧失主动力,内括约肌和前列腺位置尿道的应力分别降低33.6%、13.8%,且此位置尿液流速也降低。外括约肌单独丧失主动力,外括约肌和外尿道位置尿道应力分别降低59.5%、24.03%,而内外括约肌均丧失主动力,内括约肌、前列腺、外括约肌和外尿道位置尿道的应力分别降低38.77%、18.6%、63.58%、29.74%,且相对应位置的流速也降低。结论 内外括约肌失协同导致下尿路组织应力和尿液流速的差异性变化。研究可为手术治疗因括约肌引起的尿失禁提供理论依据。
Objective To investigate the influence of internal and external sphincter loss synergy on the stress distribution and urine flow rate of lower urinary tract organs and tissues. Methods Based on the image data of collodion slice, the geometric model of the lower urinary tract was reconstructed, and the finite element model of the lower urinary tract with muscle active force was established. Through fluid structure coupling simulation, the changes of tissue stress and urine flow rate were simulated under four conditions: normal contraction of internal and external sphincter, all loss of muscle active force and single loss of muscle active force of internal and external sphincters at the end of urination. Results The urethral stress changes in the normal contraction of the internal and external sphincter muscles were the same as the clinically measured urethral pressure changes. Compared with normal contraction, when the internal sphincter lost its muscle active force alone, the stress of the internal sphincter and the urethra of the prostate was reduced by 33.6% and 13.8%, and the flow rate of urine in this position was also reduced. When the external sphincter lost its muscle active force alone, the urethral stress of the external sphincter and external urethra was reduced by 59.5% and 24.03%, respectively. When the internal and external sphincter lost muscle active force, the stress of the internal sphincter, the prostate, the external sphincter and the external urethra were reduced by 38.77%, 18.6%, 63.58%, 29.74%, and the flow velocity at the corresponding position was also reduced. Conclusion Internal and external sphincter loss synergy resulted in the difference of tissue stress and urine flow rate. This study may provide a theoretical basis for the surgical treatment of urinary incontinence caused by sphincter.