10 Persistent Cloaca – Clinical Aspects Alexander M. Holschneider and Horst Scharbatke

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10.1 Introduction

Persistent cloaca represents the most complex de- formity in female anorectal, vaginal, and urogenital malformations. It is defined as a defect in which the rectum, one or two vaginas and the urinary tract con- verge into one common channel. It is very rare and occurs in 1:250,000 newborns [1]. It is physiological in some reptiles, birds, and a few mammals. In hu- mans, however, it represents a malformation that oc- curs at a very early stage of development.

According to Qi et al. [2] and Nievenstein et al.

[3], the rat tail gut immediately distal to the hindgut starts to regress by apoptosis on day 12 of gestation in a craniocaudal direction and has regressed com- pletely by day 13.5. This tail-gut regression and the urorectal septum play an important role in the pro- cess of cloacal separation by cellular proliferation and differentiation. Rupture of the anal membrane plays an additional role. Cloacal malformations, accord- ing to these authors, are early defects, while anorectal malformations (ARM) with the anus in the normal position are late embryonic defects. However, in the opinion of Kluth and Lambrecht [4], the embryonic cloaca never passes through a stage that is similar to any form of ARM in neonates, including the cloaca.

Contents

10.1 Introduction . . . 201

10.2 General Clinical Aspects . . . 201

10.3 Classification of Persistent Cloacas . . . 202 10.3.1 The Perineum . . . 202

10.3.2 UGS Variations . . . 202 10.3.3 Vaginal Variations . . . 202 10.3.4 Rectal Variations . . . 202 10.4 Associated Malformations . . . 203 10.5 Initial Management of the Newborn . . . 207 10.5.1 Diagnostic Management . . . 207

References . . . 208

In contrast, the cloacal membrane is always too short in abnormal rodent embryos and the region of the future anal opening is missing, in contrast to normal mouse embryos (see Chap. 4 for a detailed descrip- tion) [5].

Several experimental models of ARM including persistent cloaca exist. They are based on the terato- genic effect of ethylenethiourea in the rat [6] and ex- posure of rat fetuses to adriamycin [7] or etretinate, a long-acting vitamin A analog, in mice [8].

A molecular basis for ARM was first shown by Kimmel et al. [9]. In the murine model of ARM;

Gli3-/-mutants exhibited anal stenosis and ectopic anus, Gli2-/-mutants exhibited imperforate anus and rectourethral fistula, and Gli2-/-Gli3+/- mutants de- veloped a cloacal abnormality. In addition, isochro- mosome 18q has been shown to cause megacystis, intrauterine growth retardation, and cloacal dysgen- esis sequence in a fetus [10]. Keppler-Noreuil [11]

suggests a possible etiologic role for homeobox genes, such as HLXB9, with mutations resulting in ARM and spinal abnormalities.

10.2 General Clinical Aspects

Prenatal diagnosis of persistent cloaca has been re- ported, but is not always accurate [12,13]. In contrast, clinical diagnosis is simple. In girls, a single opening on the perineum is always suspicious of a cloacal mal- formation. The length of the introitus is characteristi- cally shorter than in a normal girl. Cloacas have only rarely been reported in boys in whom the urethra and rectum has coalesced into a common channel that is connected to the external surface in the perineal or anal area [14]. In girls, an abdominal mass and se- vere abdominal distension resulting from hydrome- trocolpos and/or rectal obstruction can frequently be observed. Additional malformations of the lower limbs, genitalia, skin (hemangioma), urogenital tract, vertebral, cardiac, and gastrointestinal deformities, among others may occur. A rarity is the posterior clo-

10 Persistent Cloaca – Clinical Aspects

Alexander M. Holschneider and Horst Scharbatke

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Alexander M. Holschneider and H. Scharbatke

202 aca, described first by Peña and Kessler [15]. In these patients the vagina and urethra fuse together but the urogenital sinus (UGS) opens into the anterior rectal wall; the rectum is normal or minimally mislocated anteriorly. The most severe type of deformity is cloa- cal exstrophy, a combination of cloaca with blad- der exstrophy that was first reported by Rickham in 1960 [16]. It is now called vesicointestinal fissure (see Chap. 14 for details).

10.3 Classification

of Persistent Cloacas

A detailed description of the varying anatomy of cloa- cal malformations has been published by Hendren [1, 17–22] and Peña [23–25]. Hendren distinguishes be-

tween anomalies of the perineum, UGS, vagina, and rectum (Table 10.1).

Table 10.1 Classification of cloacal malformations. UGS uro- genital sinus, PC pubococcygeal

Type Anomaly

Type I: Forme fruste Anteposition of anus with ultra short UGS and normal female genitalia Type II: Low cloacal

malformation Short UGS < 3 cm (confluence below PC line)

Type III: High cloacal malformation

long UGS > 3 cm (confluence at or above PC line)

Type IV: Vagina and/or rectum into bladder cavity Rare cloacal

malformations Posterior cloaca in boys Cloacal exstrophy

10.3.1 The Perineum

According to Hendren [1] there is a wide range of deformities of each pelvic structure. At the mild end of the spectrum of perineal malformations there is an almost normal-looking vaginal opening with an anal orifice that is situated very close, but not incor- porated into, the UGS. In the next degree the vagi- nal introitus might be incompletely formed and the anus displaced forward with a dysplastic perineum between both openings. There might be a large sinus urogenitalis opening and the anal opening just be- hind it, or a single perineal opening covered by the clitoris, which could be either hyper- or hypoplastic.

In a very few cases an accessory hypoplastic urethra

can be observed at the tip of the phallus in addition to the proximal urethra fusing with the UGS. The perineal skin can be covered by a hemangioma and abnormal pigmentation (Fig. 10.1 A–F).

10.3.2 UGS Variations

The UGS may exhibit an ending on the tip of the cli- toris, a subclitoral meatus, a wide opening to a short common channel, or a long sinus with the junction of urethra, vagina(s), and rectum above the pubococ- cygeal (PC) line. By using this anatomical projection of the upper border of the prostate and the ischial (I) point representing the plane of the upper border of the internal anal sphincter, high, intermediate, and low types of cloaca can be distinguished according to the Wingspread classification of ARM [26]. How- ever, there are so many variations of anomalies of the vagina, urethra, and rectum in cloacae that this clas- sification, which is very useful in ARM, is not very helpful for the classification of cloacae. Peña’s sacral ratio [25], which should be in 0.77 in normal children, gives an idea of sacral hypodevelopment and, there- fore, the probable degree of neurogenic bladder dys- function and disturbed bowel control, but is no clas- sification. Nevertheless, it is important to distinguish between high and low cloacal deformities because, for example, a UGS less than 3 cm long can be treated by total UGS advancement, whereas in longer channels an abdominal approach is necessary (Fig. 10.2) [27].

10.3.3 Vaginal Variations

The two most common variations are a single vaginal opening in the upper urethra, with the rectal opening below this orifice, and a double side-by-side vagina with the rectum ending on the septum between both vaginas. In cases of hemivaginas and an incomplete septum, the rectal fistula can be situated high on the septum; in cases with two separated vaginas it can usually be found between the vaginal openings.

There might be two vaginas but atresia, or even ab- sence of one, double diverging vaginas, two separate vaginas, or both, or two vaginas entering the bladder (Fig. 10.3 A–G).

10.3.4 Rectal Variations

The rectum can enter the UGS separate from and be-

low the vagina, may enter the posterior wall of the

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vagina or the bladder, it can be positioned between and anterior to two vaginal openings, or run as a long fistula all along the posterior wall of the vagina down to the UGS. The rectal pouch at the upper end of the fistula is very high up in these cases, sometimes even above the peritoneal reflection (Fig. 10.4).

10.4 Associated Malformations

Being a very complex deformity of a very early stage of human development, many associated anomalies can be observed in patients with cloacal malforma- tions (Table 10.2).

Fig. 10.1 Clinical aspects of cloacal malformations. A Almost normal-looking female genitalia. B Enlarged labia majora. C Male aspect of female genitalia (after drainage of hydrocolpos).

D Malformation of the labia majora. E Total malformation of the introitus; the labia majora are visible. F Labia majora not developed

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204

Fig. 10.2 Urogenital sinus (UGS) variations [modified ac- cording to Hendren (1992) J Pediatr Surg 27:890–901, Fig. 3].

a Long UGS ending in the tip of the clitoris. b Subclitoral me- atus. c Wide opening of the UGS (like a vagina). d With acces- sory tract

Vesicoureteral reflux Absence of uterus Malformations of the kidneys Bladder exstrophy

Tethered cord Gastrointestinal duplications

Neurogenic Bladder Pouch colon

Diastematomyelia Cardiac malformations

Myelomeningocele Vertebral deformities

Lower-limb deformities Esophageal atresia

Occluded tubes Cerebral anomalies

Absence of one ovary Abnormalities of the enteric nervous Hypoplastic labia

Table 10.2 Some of the associ- ated anomalies found in children with cloacal anomalies

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Fig. 10.3 Vaginal variations [modified according to Hendren (1992) J Pediatr Surg 27:890–901, Fig. 4]. a Double vagina, side by side. b Double vagina, but atresia of one. c Double, diverg- ing vagina. d Single vagina terminating in the UGS. e Two separate vaginas on each side. f Vagina entering the bladder.

g Absence of a vagina, with a uterus present

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206

Fig. 10.4 Rectal variations [modified according to Hendren (1992) J Pediatr Surg 27:890–901, Fig. 5]. a Normal anus – no cloacal malformation. b Ectopic anus. c Low confluence of the rectum into the UGS. d Short common channel. e Long com- mon channel. f Long fistula with colon at the upper end. g Rec- tal fistula entering next to the bladder neck and anterior to the vagina(s). In very rare cases only the rectum enters the bladder cavity

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10.5 Initial Management of the Newborn

There might be an urgent need for surgical interven- tion, but there is always time for detailed ultrasonog- raphy prior to laparatomy, which could reveal hydro- metrocolpos, an enlarged rectum, renal abnormalities, and tethered cord syndrome. The preliminary inter- vention should consist of a colostomy at the hepatic flexure, keeping in mind that the left colic and the sig- moidal arteries are essential for later reconstructive pullthrough procedures. A diverting pigtail catheter drainage should be introduced in the bladder and/

or vagina in case of hydrometrocolpos if intermit- tent catheterization is not possible. After the recov- ery of the baby, further detailed studies are necessary, particularly by endoscopy, with the introduction of stents in all visible urethral, vaginal, and rectal open- ings. These probes are important for a detailed x-ray studies immediately after the endoscopy. In addition, magnetic resonance imaging of the spine, intravenous pyelogram if necessary, scintigraphic studies of kid- ney function (usually some weeks later), ultrasound of the brain, and x-ray studies of skeletal anomalies and other defects should be undertaken. The final correction of the cloaca should be postponed to the age of about 1 year [22].

10.5.1 Diagnostic Management

Endoscopy includes a detailed investigation of the length of the UGS and the situation of the vagina(s), rectal fistula, the bladder neck, and urethral orifices.

In addition, a distal loopogram is essential later, be- fore definitive surgery. Without endoscopic aid it is usually not possible to catheterize the bladder because the fusion of the proximal urethra with the UGS is al- most always sharply angulated in the direction of the pubic bone. In this situation a Tieman catheter may be helpful. The endoscopic situation should be dem- onstrated to the parents to allow later intermittent catheterization by the mother until the final recon- struction is performed. In many cases, however, the urine is passed by the baby first into the vagina before being evacuated through the common channel. In these patients it is sufficient to perform intermittent catheterization of the vagina. Only very few children with a cloacal anomaly need a persistent vesicostomy or vaginostomy.

It is essential to perform the x-ray studies in a strict sagittal position, the legs elevated and the anal

dimple marked with contrast material. The complete lumbosacral spine should be visible (Figs. 10.5 and 10.6). There is a clear correlation between the degree

Fig. 10.5 Sagittal x-rays of cloacal malformations. A Low type:

short UGS, one vagina, but higher confluence of the rectum.

B High type: long UGS, one vagina visible. Note the feeding tubes in all cavities after endoscopy

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208 of vertebral and sacral malformations and the occur- rence of neurogenic voiding and defecation disorders.

A complete absence of S2–S4 leads to a lower motor neuron lesion and presents clinically as continually dribbling bladder. A disruption or severe deformity of higher lumbar neurons with intact sacral reflex activ- ity results in an autonomic or reflex bladder, leading to an upper motor neuron lesion [28,29]. However, the majority of the patients suffer from a mixed mo- tor neuron lesion with a varying amount of residual urine and uninhibited detrusor contractions.

Preoperative ultrasound may reveal tethered cord syndrome, sometimes associated with lipoma of the spinal canal or diastematomyelia. However, a teth- ered cord should be treated only when neurological problems start to arise. Many of the patients who have had detethering have experienced a retethering postoperatively due to postoperative scarring. There- fore, repeated neurological reviews by an experienced neurologist are necessary before untethering. On the other hand, it is true that once a deficit is established, it is unlikely to be improved after detethering the cord.

The best time to operate on a tethered cord therefore remains an open question.

During endoscopy fecal material should be washed out from the rectal pouch using physiologic saline so- lution. It is sometimes difficult to clean the rectum from the colostomy side even if a colostomy with two separate orifices has been established.

A detailed description of the definitive treatment of cloacal deformities is given in Chaps. 21 and 22 by Levitt and Peña.

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Fig. 10.6 Radiographic imaging of a child with a high-type cloaca: high UGS, double vagina (VAG), rectum (RECT) with fecal material A Anterior–posterior (ap) view. B Sagittal view.

BLAD Bladder

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