Dall F H, Jørgensen C S, Houe D, Gregersen H, Djurhuus J C
Institute of Experimental Clinical Research, University of Aarhus, Denmark.
Gut. 1993 Nov;34(11):1581-6. doi: 10.1136/gut.34.11.1581.
Biomechanical properties of the rectal wall were studied in 17 healthy adult volunteers (nine men and eight women). With impedance planimetry it is possible to obtain simultaneous measurements of pressure and rectal cross sectional area (CSA) during balloon inflations. Rectal distensions were done with an intraluminal balloon using specified pressures up to 40 cmH2O above baseline rectal pressure. Balloon inflation elicited a phase of rapid increase in rectal CSA followed by a phase of slow increase until a steady state was reached. Steady state occurred within 67 to 140 seconds with the shortest period at the highest distension pressures. Steady state rectal CSA values had a non-linear relation to increasing distension pressure. Rectal CSA values in women showed a tendency of being slightly higher than male values at all pressure steps with a significant difference at 3 and 5 cm H2O. Biomechanical parameters were calculated from rectal CSA pressure relations. Circumferential wall tension increased in a linear way. Rectal compliance decreased in a non-linear way with no further decline between 30 and 40 cmH2O. The pressure elastic modulus increased steeply until a distension pressure of 35 cmH2O with no further increase to 40 cmH2O. This suggests that rectal tone is reduced as the muscle fails to resist further distension at 35 cmH2O and higher pressures. Impedance planimetry offers new possibilities for investigation of anorectal physiology through the study of segmental biomechanical wall properties of the human rectum.
对17名健康成年志愿者（9名男性和8名女性）的直肠壁生物力学特性进行了研究。通过阻抗平面测量法，可以在球囊充气过程中同时测量压力和直肠横截面积（CSA）。使用腔内球囊以高于基线直肠压力40 cmH2O的特定压力进行直肠扩张。球囊充气引发直肠CSA快速增加阶段，随后是缓慢增加阶段，直至达到稳定状态。稳定状态在67至140秒内出现，在最高扩张压力下持续时间最短。稳定状态下的直肠CSA值与扩张压力增加呈非线性关系。在所有压力步骤中，女性的直肠CSA值均有略高于男性值的趋势，在3 cmH2O和5 cmH2O时差异显著。根据直肠CSA与压力的关系计算生物力学参数。圆周壁张力呈线性增加。直肠顺应性呈非线性下降，在30至40 cmH2O之间无进一步下降。压力弹性模量在扩张压力达到35 cmH2O之前急剧增加，到40 cmH2O时不再增加。这表明在35 cmH2O及更高压力下，由于肌肉无法抵抗进一步扩张，直肠张力降低。阻抗平面测量法通过研究人体直肠的节段性生物力学壁特性，为肛管直肠生理学研究提供了新的可能性。
