Bingham George, Leslie Stephen W., Rentea Rebecca M.
University College London Hospital
Creighton University School of Medicine
Posterior urethral valves are the most common cause of urinary tract obstruction and chronic kidney disease resulting from obstructive uropathy in the pediatric population. The valves are actually obstructing membranous folds situated within the posterior urethral lumen attached to the verumontanum. These folds are found exclusively in male patients. Posterior urethral valves were first described by Morgagni in 1717. Langenbeck further observed valve-like folds in dissected cadavers in 1802, and Hugh Hampton Young reaffirmed their presence in 1919. Posterior urethral valves can lead to a broad range of pathological conditions, spanning from asymptomatic cases to incompatible with sustaining life. Complications may encompass acute and chronic urinary retention, renal failure, bladder outlet obstruction, hydroureteronephrosis, vesicoureteral reflux, voiding dysfunction, and, in severe cases, pulmonary hypoplasia secondary to decreased amniotic fluid levels. Posterior urethral valves are classically split into 3 subtypes based on Young's criteria, which delineate the orientation of the valves within the urethra. Posterior urethral folds (plicae colliculi) originate from the caudal verumontanum along the lateral margins of the urethra. These folds fuse anteriorly, causing an obstruction. They represent remnants of the Wolffian duct. Bicuspid leaflets or membranes are attached to the bladder neck proximally, originating from the verumontanum. These are now considered hypertrophic plicae colliculi, not true obstructive posterior urethral valves. A round membrane situated at the caudal verumontanum, featuring a hole in the middle that is either above the verumontanum (type IIIa) or below (type IIIb). Neither subtype's hole directly communicates with the verumontanum. Nevertheless, this classification has faced challenges. Dewan suggested that types I and III, as Young described, may represent the same structure. They posit that these structures appear distinct only because a central defect ruptures antenatally either naturally or due to iatrogenic instrumentation before birth. In place of the term posterior urethral valves, Dewan introduced the concepts of a congenital obstructive posterior urethral membrane and "Cobb's collar." : An alternative term for the classic type of posterior urethra valves and is always associated with the verumontanum. This congenital lesion manifests as a potentially obstructive proximal membrane featuring paramedian folds or leaflets extending along the posterior urethral wall to the verumontanum. Not a valve or a classical posterior urethral valve but a congenital bulbar urethral stricture or obstructive membrane unassociated with the verumontanum. Located distally to the verumontanum in the bulbar urethra, it remains separate from the verumontanum and the external urinary sphincter. This anomaly is believed to represent a persistent remnant of the urogenital membrane.
后尿道瓣膜是小儿人群中泌尿道梗阻和梗阻性肾病导致慢性肾脏病的最常见原因。这些瓣膜实际上是位于后尿道管腔内附着于精阜的梗阻性膜状皱襞。这些皱襞仅在男性患者中发现。后尿道瓣膜于1717年由莫尔加尼首次描述。1802年，朗根贝克在解剖尸体时进一步观察到瓣膜样皱襞，1919年休·汉普顿·扬再次证实了它们的存在。后尿道瓣膜可导致广泛的病理状况，从无症状病例到危及生命的情况。并发症可能包括急慢性尿潴留、肾衰竭、膀胱出口梗阻、肾盂输尿管积水、膀胱输尿管反流、排尿功能障碍，严重时还包括羊水过少继发的肺发育不全。后尿道瓣膜根据扬氏标准经典地分为3个亚型，该标准描述了瓣膜在尿道内的方向。后尿道皱襞（尿道嵴）沿尿道外侧缘起自精阜尾侧。这些皱襞在前方融合，造成梗阻。它们代表中肾管的残余。双叶瓣膜或膜近端附着于膀胱颈，起自精阜。现在认为这些是肥厚的尿道嵴，而非真正梗阻性的后尿道瓣膜。一个圆形膜位于精阜尾侧，中间有一个孔，该孔要么在精阜上方（Ⅲa型），要么在其下方（Ⅲb型）。两种亚型的孔均不直接与精阜相通。然而，这种分类面临挑战。德万认为，扬所描述的Ⅰ型和Ⅲ型可能代表相同结构。他们认为这些结构看起来不同只是因为中央缺损在产前自然破裂或因出生前的医源性操作而破裂。德万引入了先天性梗阻性后尿道膜和“科布环”的概念来取代后尿道瓣膜这一术语。：经典型后尿道瓣膜的另一个术语，且总是与精阜相关。这种先天性病变表现为一个潜在梗阻性的近端膜，有沿着后尿道壁延伸至精阜的旁正中皱襞或瓣膜。不是瓣膜或经典的后尿道瓣膜，而是一种与精阜无关的先天性球部尿道狭窄或梗阻性膜。位于球部尿道精阜远侧，与精阜和尿道外括约肌分开。这种异常被认为代表尿生殖膜的持续残余。
