Cloacal Anomalies

(1)

Pediatric Surgery, AlSadik Hospital, Qatif, Saudi Arabia

15.1 Introduction

In animal anatomy, a cloaca/kloʊˈeɪkə/kloh–ay–kə (plural cloacae /kloʊˈeɪsiː/kloh–ay–see) is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts of certain animals.
All amphibians, birds, reptiles, and a few mammals have this orifice, from which they excrete both urine and feces.
This is in contrast to most placental mammals, which have two or three separate orifices for evacuation.
The word cloaca comes from Latin, and means sewer derived from cluō, which meant “cleanse”.
A persistent cloaca is a complex congenital birth defect in which there is a confluence of the rectum, vagina, and urethra into a single common channel (Figs. 15.1 and 15.2).

Fig. 15.1

A diagrammatic representation of cloaca. Not the urethra, vagina and rectum opening in a common channel. The length of the common channel is important for prognosis

Fig. 15.2

A clinical photograph of a patient with cloaca. Note the common single perineal opening. No separate urethral or anal openings seen
The exact incidence of cloacal anomalies is unknown but it is estimated to occur in 1 per 20,000–25,000 live births.
Cloacal anomalies occur exclusively in girls.
They comprise the most complex defect in the spectrum of anorectal malformations.
The management of these patient is challenging and these patients should be managed in specialized centers with surgeons experienced in the management of these patients.
The goals of treatment include an anatomic reconstruction with the aim of achieving:
- Urinary control
- Bowel control
- Sexual function
Persistent cloacae occur exclusively in girls and is considered the most complex and technically challenging defect in the spectrum of anorectal malformations.
The etiology of persistent cloaca is unknown.
A common error in the diagnosis of cloaca may occur during the neonatal period where physician may confuse it with high anorectal malformation with a rectovaginal fistula.
The cooperation of a pediatric surgeon and pediatric urologist is important in this regard.
Cloacae represent a spectrum of defects, but the common denominator is the presence of a single perineal orifice and the rectum, vagina, and urethra open into a single common channel.
The length of this common channel is variable and ranges from 1 to 10 cm, with an average length of approximately 3 cm.
The length of this common channel is important both surgically and also for prognosis.
More than 80 % of all patients with a cloaca have an associated urogenital anomaly.
All patients must be evaluated at birth for an associated urologic malformation.
The goals of treatment include an anatomic reconstruction to achieve bowel and urinary control, as well as normal sexual function.
In 1982, Pena introduced the posterior sagittal approach to repair high anorectal malformation. This technique was also used to repair cloacal malformations.
This technique is extended and used to repair the more complex cloacae and it is called the posterior sagittal anorectovaginourethroplasty (PSARVUP).
This approach allowed for direct exposure to the complex anatomy and an excellent visualization and repair of the voluntary muscles of urinary and fecal continence.
It is important to accurately diagnose persistent cloaca in the neonatal period because 90 % of these patients have an associated urologic problem, and 40 % of them may present also with an abdominal mass secondary to hydrocolpos.
The hydrocolpos may produce two important complications:
- It may compress the trigone of the urinary bladder, producing ureterovesical obstruction, megaureter, and hydronephrosis.
- The vagina may become obstructed leading to accumulation of the cervical glands secretion. This leads to the formation of hydrocolpos.
- Hydrocolpos if left undrained may become infected, leading to a pyocolpos.
Approximately 40 % of patients with cloaca have a double Mullerian system consisting of two hemiuteri and two hemivaginas.
This septation disorder may be partial or total and symmetric or asymmetric.
It is important to recognize and document this for future follow-up of these patients.
The urinary tract and the distended vagina (Hydrocolpos) may both need to be managed within the newborn period to avoid serious complications. Drainage of the distended vagina may lead to resolution of the secondary urological complications.
The goals of management of cloaca include:
- Early and accurate diagnosis of both cloaca and associated anomalies.
- Immediate neonatal management including fecal, urinary and vaginal diversion depending on the presentation.
- An anatomic reconstruction to achieve bowel and urinary control, as well as normal sexual function.
Currently, the posterior sagittal anorectovaginourethroplasty (PSARVUP) is the preferable approach to treat cloacal malformations. This approach is important for direct exposure to the complex anatomy and also allows excellent visualization of the voluntary muscles of urinary and fecal continence.

15.2 Associated Anomalies

Associated anomalies are common in patients with cloaca.
More than 80 % of all patients with a cloaca have an associated urogenital anomaly.
These include:
- Absent kidney
- Vesicoureteral reflux
- Horseshoe kidney
- Ectopic ureters
- Double ureters
- Hydronephrosis, and megaureters as a result of vesicoureteral reflux or ureterovesical obstruction.
Tethered cord:
- Tethered cord has a known association with anorectal malformations and is particularly common in patients with persistent cloaca.
- A tethered spinal cord refers to an intravertebral fixation of the phylum terminale.
- This may result in motor and sensory disturbances of the lower extremities.
- Spinal ultrasonography in the first 3 months of life and MRI thereafter are useful in diagnosis of tethered cord and associated spinal and sacral anomalies.
- Patients with tethered cord have a worse functional prognosis regarding bowel and urinary function.
- Add to this the less-developed sacra, associated spinal problems, and less-developed perineal musculature.
- The input of a neurosurgeon in this is important as release of a tethered cord may improve the functional outcome especially the urodynamics.
- Anomalies of the sacrum, particularly hypodevelopment, sacral hemivertebrae, and hemisacra, are associated with tethered cord and most likely comprise the spectrum of caudal regression, of which spinal anomalies are a part.
Patients with anorectal malformations and tethered cord have a worse functional prognosis regarding bowel and urinary function.
Sacrum and spine anomalies:
- The sacrum is the most frequently affected bony structure.
- Associated anomalies of the sacrum include hemisacrum, hypodevelopment of the sacrum and sacral hemivertebrae.
- The degree of sacral deficiency is assessed by calculating the sacral ratio.
- The sacrum is measured, and its length is compared with bony parameters of the pelvis on an anteroposterior and a lateral radiographs.
- Calculation of sacral ratio:
  
  The distance from the coccyx to the sacroiliac joint divided by the distance from the sacroiliac joint to the top of the pelvis.
- The assessment of the hypodevelopment of the sacrum correlates with the patient’s functional prognosis.
- Normal sacra have a ratio of greater than 0.7.
- Bowel control has rarely been observed in patients with ratios less than 0.3.
- A hemisacrum is almost always associated with a presacral mass, commonly a presacral teratoma, or an anterior meningocele.
- This may be part of the Currarino triad, which includes:
  
  An anorectal malformation
  
  A hemisacrum
  
  A presacral mass
- Hemivertebrae may also affect the lumbar and thoracic spine, leading to scoliosis.
- Patients with cloaca may also have spinal anomalies other than tethered cord, such as syringomyelia and myelomeningocele.
Genital anomalies:
Approximately 50 % of patients have various degrees of vaginal or uterine septation.
- Absent vagina
- 2 hemivagina
- 2 hemiuteri

15.3 Classification

Cloacae represent a wide spectrum of anomalies.
In all, the rectum, vagina and urethra open together in a common channel.
The length of this common channel is variable and ranges from 1 to 10 cm with an average of 3 cm.
The length of this common channel is important both for management and prognosis.
Based on the length of the common channel cloacae are divided into two main groups:
1. 1.
  
  Short common channel: The length of the common channel is less than 3 cm (Figs. 15.3 and 15.4)
2. 2.
  
  Long common channel: The length of the common channel is more than 3 cm (Fig. 15.4).
Figs. 15.3 and 15.4

Diagrammatic representation of cloaca. Note the length of the common channel which is variable ranging from 1 to 10 cm but commonly around 3 cm. The cloaca is divided into two types, low and high based on the length of the common channel. It is a short common channel if the length of the common channel is less than 3 cm and log common channel if it is more than 3 cm