Department of Urology and Transplant Surgery, Beaumont Hospital, Dublin, Ireland.
Centre for Applied Biomedical Engineering Research, School of Engineering, Bernal bInstitute and the Health Research Institute, University of Limerick, Limerick, Ireland.
J Mech Behav Biomed Mater. 2018 Jul;83:102-107. doi: 10.1016/j.jmbbm.2018.04.015. Epub 2018 Apr 19.
Data on urethral catheter related injuries is sparse. In this study we aimed to characterise urethral diametric strain and urinary catheter inflation pressure thresholds that precede human urethral trauma during urethral catheterisation (UC). Human urethras were obtained from patients undergoing male to female gender reassignment surgery [(n = 9; age 40 ± 13.13 (range: 18-58)) years]. 12Fr urinary catheters were secured in the bulbar urethra and the catheter's anchoring balloon was inflated with a syringe pump apparatus. Urethral diametric strain and balloon pressure were characterised with video extensometry and a pressure transducer respectively. Immunohistochemistry, Masson's trichrome and Verhoeff-Van Gieson stains evaluated urethral trauma microscopically. Morphological characterisation of the urethral lumen was performed by examining non-traumatised histological sections of urethra and recording luminal area, perimeter and major/minor axis length. Tearing (n = 3) and rupture (n = 3) of the urethra were observed following catheter balloon inflation. The threshold for human urethral rupture occurred at an external urethral diametric strain ≥ 27% and balloon inflation pressure ≥ 120kPa. Significant relationships were identified between urethral wall thickness and the level of trauma induced during catheter balloon inflation (p = 0.001) and between the pressure required to inflate the catheter balloon and the length of the major axis of the urethral lumen (p = 0.004). Ruptured urethras demonstrated complete transection of collagen, elastin and muscle fibres. In conclusion, urethral rupture occurs at an external urethral diametric strain ≥ 27% or with balloon inflation pressures ≥ 120 kPa. Incorporation of these parameters may be useful for designing a safety mechanism for preventing catheter inflation related urethral injuries.
关于尿道导管相关损伤的数据很少。在这项研究中，我们旨在描述尿道导管插入术 (UC) 期间导致人类尿道创伤的尿道直径应变和导尿管膨胀压力阈值。我们从接受男性到女性性别重置手术的患者中获得了尿道 [(n=9; 年龄 40±13.13(范围：18-58)岁)]。将 12Fr 导尿管固定在球部尿道中，并使用注射器泵装置使导管的锚固球囊膨胀。使用视频伸长计和压力传感器分别对尿道直径应变和球囊压力进行了特征描述。免疫组织化学、马松三色和 Verhoeff-Van Gieson 染色对尿道创伤进行了显微镜评估。通过检查未受伤的尿道组织学切片并记录管腔面积、周长和长/短轴长度，对尿道管腔的形态特征进行了研究。在导管球囊充气后观察到尿道撕裂 (n=3) 和破裂 (n=3)。人类尿道破裂的阈值为尿道外直径应变≥27%和球囊膨胀压力≥120kPa。在导管球囊充气过程中诱导的创伤程度与尿道壁厚度之间 (p=0.001) 和充气所需的压力与尿道管腔长轴长度之间 (p=0.004) 存在显著关系。破裂的尿道显示出胶原、弹性蛋白和肌肉纤维的完全横断。总之，尿道破裂发生在尿道外直径应变≥27%或球囊膨胀压力≥120kPa 时。这些参数的结合可能有助于设计预防导管充气相关尿道损伤的安全机制。
