Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Blvd. 82, DK-8200 Aarhus N, Denmark; Department of Urology, Section of Paediatric Urology, Aarhus University Hospital, Palle Juul-Jensens Blvd. 99, DK-8200 Aarhus N, Denmark.
Department of Urology, Section of Paediatric Urology, Aarhus University Hospital, Palle Juul-Jensens Blvd. 99, DK-8200 Aarhus N, Denmark; Department of Public Health, Section for Epidemiology, Aarhus University, Bartholins Allé 2 - Building 1260, DK-8000 Aarhus C, Denmark.
J Pediatr Urol. 2019 Feb;15(1):62.e1-62.e7. doi: 10.1016/j.jpurol.2018.09.004. Epub 2018 Sep 19.
The ventral aspect of the penis in boys with hypospadias is composed of dysplastic tissue of the skin and the urethra. The aim of this study was to assess the pre-operative size and biomechanical properties of urethrae in boys with and without hypospadias using a more objective catheter-based system.
MATERIALS & METHODS: In this non-blinded clinical observation study, the study population consisted of 19 boys with hypospadias-the case group (median age 13.9 months [range: 12.2-21.3])-and seven boys without hypospadias-the control group (median age 8.5 months [range: 3.8-18.1]). Modified measurements of impedance were used to assess the size, compliance and viscoelasticity of the urethrae under stepwise increased pressures (between 0, 40 and 60 cmHO) using a customised Endolumenal Functional Lumen Imaging probe (EndoFLIP®).
The sizes of the urethrae in boys with hypospadias are variable but tend towards being narrower and less compliant than those of the control subjects i.e. median diameter for meatus urethra was 3.2 mm (range: 2.98-3.92) in the hypospadias group compared with 3.64 (range: 3.22-4.44) in the control group at 40 cmHO, and the median change in diameter at meatus urethra was 0.08 mm (range: -0.02 to 0.52) in the hypospadias group compared with 0.23 mm (range: -0.02 to 0.34) when the pressure was increased from 40 to 60 cmHO. This biomechanical analysis found that there was no significant viscoelasticity of the urethral meatus in both the groups, whereas the remainder of the urethral structure generally had viscoelastic properties in the control group, seen as a creep on the time/diameter curves (Figure). In the group of boys with hypospadias, evaluations of the urethrae revealed varying viscoelastic abilities, ranging from abilities that were comparable with those of the control subjects to no sign of viscoelasticity at all.
This study is the first to measure the biomechanical properties of the urethra in children, which might help to provide an understanding as to the structural and functional changes associated with hypospadias. The urethrae in the subjects with hypospadias were variable in diameter but tended to be narrower overall, especially in the distal portion of the urethra. Furthermore, the urethrae in boys with hypospadias were frequently less viscoelastic than those of controls.
The EndoFLIP® system may be a future way of objectively estimating the severity of a urethral obstruction and could potentially be included in the postoperative assessment of patients with signs of hampered voiding.
男孩尿道下裂的阴茎腹侧由皮肤和尿道的发育不良组织组成。本研究旨在使用更客观的基于导管的系统评估有和无尿道下裂男孩的尿道术前大小和生物力学特性。
在这项非盲临床观察研究中，研究人群包括 19 名患有尿道下裂的男孩（病例组，中位年龄 13.9 个月[范围：12.2-21.3]）和 7 名无尿道下裂的男孩（对照组，中位年龄 8.5 个月[范围：3.8-18.1]）。使用改良的阻抗测量法，使用定制的腔内功能内腔成像探头（EndoFLIP®），在逐步增加的压力（0、40 和 60 cmHO 之间）下评估尿道的大小、顺应性和粘弹性。
患有尿道下裂的男孩的尿道大小各不相同，但与对照组相比，尿道直径往往更窄，顺应性更低，即尿道口直径在 40 cmHO 时为 3.2mm（范围：2.98-3.92），对照组为 3.64mm（范围：3.22-4.44），尿道口直径的中位变化为 0.08mm（范围：-0.02 至 0.52）在尿道下裂组中，当压力从 40 增加到 60 cmHO 时，对照组为 0.23mm（范围：-0.02 至 0.34）。这项生物力学分析发现，两组尿道的尿道口都没有明显的粘弹性，而尿道的其余部分在对照组中通常具有粘弹性特性，表现在时间/直径曲线上的蠕变（图）。在患有尿道下裂的男孩组中，对尿道的评估显示出不同的粘弹性能力，从与对照组相当的能力到根本没有粘弹性的迹象不等。
这项研究首次测量了儿童尿道的生物力学特性，这可能有助于了解与尿道下裂相关的结构和功能变化。患有尿道下裂的受试者的尿道直径不同，但总体上往往更窄，尤其是在尿道的远端部分。此外，与对照组相比，患有尿道下裂的男孩的尿道往往粘弹性较差。
EndoFLIP®系统可能是一种客观估计尿道梗阻严重程度的未来方法，并可能被纳入术后评估有排尿困难迹象的患者。
