Anorectal Atresia and Cloacal Malformations Flashcards
A newborn male is born without an anus. If a fistula is present, what is the most likely location?
A. Rectovestibular
B. Rectourethral
C. Rectoperineal
D. Rectovesicular
E. Rectoenteric
ANSWER: B
COMMENTS: The most common site of a fistula associated with imperforate anus in males is rectourethral, while rectovestibular fistulas are the most common in females.
Only 5% of patients with imperforate anus do not have a fistula.
If meconium is passed in the urine, a fistulous connection to the urinary system should be suspected. If meconium is found on the perineum, a rectoperineal fistula is likely.
The initial management of an imperforate anus is to evaluate for other associated anomalies.
Babies with an imperforate anus have a 50%–60% likelihood of associated anomalies.
An imperforate anus is a part of the VACTERL group of associated congenital defects (vertebral anomalies, imperforate anus, cardiac abnormalities, TEFs, renal abnormalities, and limb abnormalities).
Babies born with any of these conditions should be evaluated for the presence of the others within the first 24 h of life.
Next, the level of the lower end of the rectal pouch must be determined.
Imperforate anus is usually divided into high and low types, and this will guide treatment.
Within 24 h of birth, gas will make its way through the GI tract and into the rectal pouch.
A cross-table radiograph of the infant will show the gas in the rectal pouch.
The high imperforate anus is diagnosed when air fails to pass below the level of the coccyx, and it is associated with more secondary anomalies compared with the low imperforate anus.
Once an imperforate anus is found, a fistula should be sought.
If a perineal fistula is present, the rectal pouch is usually low, and a perineal anoplasty can be performed in the perinatal period for definitive management.
If there is rectal gas below the coccyx but no fistula, a posterior sagittal anorectoplasty, or posterior sagittal anorectoplasty (PSARP), during the neonatal period could be considered.
However, if the level is high or if the infant has other significant defects and is not clinically stable, a colostomy should be constructed and definitive repair postponed.
What is a high pressure distal colostogram?
A high pressure distal colostogram is performed through the mucous fistula at several months of life in order to delineate the length of the rectum, rectum to perineal distance, and the location of the fistula.
Without a properly performed distal colostogram, the surgeon will not know the precise location of the distal rectum.
There are risks of injuring adjacent structures including the vas deferens, urethra, seminal vesicles and bladder neck. Recent work with water injection and visualization using ultrasound could replace the use of ionizing radiation used during fluoroscopy.
A 4-year old male presents with a history of an international adoption and prior anorectal malformation repair, (original malformation unknown). He voids incompletely and dribbles urine after voiding. How would you evaluate this child?
Children who have undergone surgery for an anorectal malformation who present with fecal and/or urinary incontinence always require a complete workup for associated anomalies especially in the setting where their surgical record is unknown.
In this case the child could have a remnant of the original fistula (ROOF) leading to urinary dribbling.
This can be evaluated by pelvic MRI and cystoscopy.
The possibility of a neurogenic bladder must also be investigated. A voiding cystourethrogram (VCUG) and video urodynamics (UDS) should be included in the work up as well.
In a male with ARM, distal colostogram shows a high rectum with no fistula. On the contrast study the distal end of the rectum appears flat. What should be the next step in management?
Request a repeat distal colostomy with higher pressure.
In a male ARM patient with a rectobladderneck fistula, mobilization of a very high rectum requires:
Dissection of the distal IMA branches thus preserving the intramural rectal blood supply to the distal rectum.
In a male ARM patient, unilateral hydronephrosis is likely related to:
Vesicoureteral reflux.
In a male ARM patient, the “no fistula” defect is almost always located at the level of:
Bulbar urethra.
A previously repaired ARM patient is found to have mislocated anus with rectal prolapse. MRI of the pelvis reveals a mass behind the urethra. Reoperation is considered. The posterior urethral mass most likely represents:
R.O.O.F. Remnant Of Original Fistula.
What are appropriate ways to manage an infant with imperforate anus and a rectovestibular or rectoperineal fistula?
This infant has several options depending on the comfort and expertise of the surgeon and parental preferences.
(1) A colostomy can be performed in the newborn period followed by repair at 3–10 months of age and eventually colostomy closure.
(2) Dilations of the fistulous tract to Hegar # 10 with delayed repair at 3 to 6 months of age.
(3) Primary PSARP in the newborn period with or without a protecting colostomy (Fig. 34.4).
What are the indications for the treatment of a rectoperineal fistula in a female?
First, it is crucial to delineate the location of the fistula in relation to the sphincter complex.
The definitive diagnosis is with an examination under anesthesia with electrical stimulation of the sphincter complex.
The goals of the operation are then to relocate the anus within the sphincter mechanism, make the anal opening an appropriate size for patient’s age, and create an adequate length of perineal body. If, however, the anal opening is circumferentially surrounded by the sphincter muscle complex, then a short or inadequate perineal body alone is not an indication for operation.
What are the key steps of a posterior sagittal anorectoplasty (PSARP)?
- Place a Foley catheter (Coude tip preferred)
- Position the patient prone, elevate the pelvis, prep and drape
- Identify the center of the sphincter complex with an electrical stimulator and mark the site
- Make a posterior sagittal incision
- Separate the fistula/rectum from the urethra
- Divide and close the fistula
- Stimulate the sphincter muscle complex again while the muscle complex is open to confirm the site of the anoplasty
- Reapproximate the levators and midline structures incorporating the rectum with at least 3–4 sutures to prevent prolapse.
- Place the rectum in the center of the sphincter complex
- Perform the anoplasty and size the neoanus with a Hegar dilator.
What is a high pressure distal colostogram?
A high pressure distal colostogram is performed through the mucous fistula at several months of life in order to delineate the length of the rectum, rectum to per- ineal distance, and the location of the fistula.
Without a properly performed distal colostogram, the surgeon will not know the precise location of the distal rectum.
There are risks of injuring adjacent structures including the vas deferens, urethra, seminal vesicles and bladder neck.
Recent work with water injection and visualization using ultrasound could replace the use of ionizing radiation used during fluoroscopy [1].
A 4-year old male presents with a history of an international adoption and prior anorectal malformation repair, (original malformation unknown). He voids incompletely and dribbles urine after voiding. How would you evaluate this child?
Children who have undergone surgery for an anorectal malformation who present with fecal and/or urinary incontinence always require a complete workup for associated anomalies especially in the setting where their surgical record is unknown.
In this case the child could have a remnant of the original fistula (ROOF) leading to urinary dribbling [2].
This can be evaluated by pelvic MRI and cystoscopy.
The possibility of a neurogenic bladder must also be investigated. A voiding cystourethrogram (VCUG) and video urodynamics (UDS) should be included in the work up as well.
In a male with ARM, distal colostogram shows a high rectum with no fistula. On the contrast study the distal end of the rectum appears flat. What should be the next step in management?
Request a repeat distal colostomy with higher pressure.
In a male ARM patient with a rectobladderneck fistula, mobilization of a
very high rectum requires:
Dissection of the distal IMA branches thus preserving the intramural rectal blood supply to the distal rectum.
In a male ARM patient, unilateral hydronephrosis is likely related to:
Vesicoureteral reflux.
In a male ARM patient, the “no fistula” defect is almost always located at the level of:
Bulbar urethra.
A previously repaired ARM patient is found to have mislocated anus with rectal prolapse. MRI of the pelvis reveals a mass behind the ure- thra. Reoperation is considered. The posterior urethral mass most likely represents:
R.O.O.F. Remnant Of Original Fistula.
What are appropriate ways to manage an infant with imperforate anus and a rectovestibular or rectoperineal fistula?
This infant has several options depending on the comfort and expertise of the surgeon and parental preferences.
(1) A colostomy can be performed in the newborn period followed by repair at 3–10 months of age and eventually colostomy closure.
(2) Dilations of the fistulous tract to Hegar # 10 with delayed repair at 3 to 6 months of age.
(3) Primary PSARP in the newborn period with or without a protecting colostomy (Fig. 34.4).
What are the indications for the treatment of a rectoperineal fistula in a female?
First, it is crucial to delineate the location of the fistula in relation to the sphincter complex.
The definitive diagnosis is with an examination under anesthesia with electrical stimulation of the sphincter complex.
The goals of the operation are then to relocate the anus within the sphincter mechanism, make the anal opening an appropriate size for patient’s age, and create an adequate length of perineal body.
If, however, the anal opening is circumferentially surrounded by the sphincter muscle complex, then a short or inadequate perineal body alone is not an indication for operation.
What are the key steps of a posterior sagittal anorectoplasty (PSARP)?
• Place a Foley catheter (Coude tip preferred)
• Position the patient prone, elevate the pelvis, prep and drape
• Identify the center of the sphincter complex with an electrical stimulator and mark the site
• Make a posterior sagittal incision
• Separate the fistula/rectum from the urethra
• Divide and close the fistula
• Stimulate the sphincter muscle complex again while the muscle complex is
open to confirm the site of the anoplasty
• Reapproximate the levators and midline structures incorporating the rectum with at least 3–4 sutures to prevent prolapse.
• Place the rectum in the center of the sphincter complex
• Perform the anoplasty and size the neoanus with a Hegar dilator.
A female newborn is found to have only two perineal openings, what are the defects that could be responsible?
Rectovaginal fistula, urogenital sinus, a blind ending rectal fistula, vestibular fistula with vaginal atresia.
Describe the anorectal malformation in which a female infant with imperforate anus, has only a single perineal opening?
Cloaca. In this malformation, rectum, vagina and urinary tract empty into a single common channel.
You are asked to perform a fetal consultation for a pregnant woman with a 24-week female fetus who on prenatal ultrasound has a cystic pelvic mass, an absent radial bone, and a single kidney with hydronephrosis. What is the most likely diagnosis?
Cloaca. A single perineal orifice in a female that forms a common channel consisting of the urinary tract, reproductive tract and rectum.
The cystic mass is likely a vagina filled with mucous and urine (hydrocolpos), and the radial and renal anomalies are part of the VACTERL complex.
What is the incidence of cloaca?
1 in 50,000 females.
What is hydrocolpos?
Hydrocolpos is the distension of the vagina caused by accumulation of fluid in the vagina (mucous and urine).
It may be problematic when it obstructs the distal ureters by compressing the bladder trigone and resulting in hydronephrosis.
In these cases, hydrocolpos needs to be drained.
In the management of a newborn with a cloaca, how do you determine whether a hydrocolpos requires drainage?
If there is hydronephrosis associated with the pelvic mass, the hydrocolpos will need to be drained.
How can a hydrocolpos be drained?
There are two options for the drainage of hydrocolpos.
(1) Intermittent catheterization of the common channel, with confirmation of decompression and resolution of hydronephrosis by ultrasound
(2) A transabdominal vaginostomy tube either by interventional radiology or at the time of colostomy creation.
Which anatomic details are vital to surgical planning in cloaca?
Length of the common channel (<3 cm short common channel vs. >3 cm long common channel) and urethral length (measurement based on a cloaca up to one year of age).
These are vital in deciding whether a total urogenital mobilization or a urogenital separation with preservation of the common channel as urethra should be performed [6] (Fig. 34.5).
Identify key steps in the newborn management of cloacal malformations.
- Identify the single perineal opening and confirm the diagnosis.
- Divert the fecal stream via a divided descending colostomy
- Determine whether a hydrocolpos causing hydronephrosis is present, and if so drain it via perineal catheterizations or vaginostomy.
- Evaluate for associated anomalies (VACTERL)
- Perform a cystoscopy, vaginoscopy, and a contrast study to visualize the anatomy (3D reconstructed fluoroscopy) at 5 to 6 months of age
- Perform a definitive cloacal repair between 6 months to 1 year of age.
A 13 years old previously repaired cloacal patient, presents with cyclical, monthly left lower quadrant abdominal pain. What is the most likely diagnosis?
Hematometrocolpos associated with an obstructed Mullerian structure.
What is the most common indication for a reoperation in patients with previously repaired cloaca?
Persistent urogenital sinus, i.e. only the rectal component was previously repaired.
In a patient with previously repaired ARM patient, what is the most important predictor of continence? Type of malformation? Status of the spine? Quality of the Sacrum?
All three are important variables to consider when counseling patients on their continence potential. We use Fig. 34.6 to counsel families. A recent study has shown that the type of ARM was the only factor that predicted fecal continence in children with ARM.
An ARM patient has successful bowel management program with enemas and requests an antegrade enema route. For his urine, he does intermittent catheterization but leaks at 2 h. What is the next step in management? What are his options for antegrade route?
For patients on intermittent catheterization leaking at 2 h, strong consideration should be given to urology referral.
The patient should undergo urology evaluation with urodynamics, VCUG, and renal ultrasound.
If patient needs a Mitrofanoff, then consideration should be given to split appendix Malone/Mitrofanoff.
If the length of the appendix is not adequate then appendix should be used for Mitrofanoff and neomalone should be constructed.
If the cecum is not amenable to neomalone due to vascular supply, then a cecostomy should be considered (Fig. 34.7).
What is cloacal exstrophy?
It is a severe form of anorectal malformation with ventral abdominal wall defects.
The classic features of cloacal exstrophy include anorectal malformation, omphalocele, blind ending micro-colon, exstrophic hemibladders, and an everted cecum with prolapse between them.
Boys often have a rudimentary hemiphallic structures on each side.
Females may have many gynecologic anomalies.
The incidence of cloacal exstrophy is 1 in every 400,000 births with a male predominance [4].
Name the key steps in the management of a newborn with cloacal exstrophy.
- Careful preoperative investigation
- Omphalocele closure
- Separation of the gastrointestinal tract from the hemibladders with tubularization of the cecum and construction of an end colostomy (gastrointestinal stoma)
- Closure of hemibladders, if possible, or if not, joining them together and keeping them inverted
- Pelvic osteotomies of the time of bladder closure
- Delayed additional urogenital reconstruction, depending on gender assignment
- Colonic pullthrough plus malone if end stoma is capable of forming solid stool.
What is the pubococcygeal line?
It is a line that joins the upper border of the symphysis pubis to the sacrococcygeal junction.
A gas bubble situated above the PC line is designated as a “high” anomaly.
A gas bubble located between the PC line and I line is designated as an intermediate anomaly.
A gas bubble extends below the I line, it is called a “low” anomaly.
How do you do an invertogram for Anorectal Malformations?
The baby was originally positioned upside-down. This has been replaced by a prone, cross-table lateral position, with the hips elevated with a bolster (12-24h after birth to allow gas to reach the distal rectum). Strict lateral view is taken with the thighs flexed at the hip, and beam accurately centered on the greater trochanter.
Anal dimple and natal cleft should be outlined by barium paste, coin, metal pointer.
In a correctly taken radiograph:
- Both the ischial bone would accurately superimpose.
- The terminal blind bowel will be rounded and well-distended.
Things to evaluate in an invertogram: - Level of gas in the blind pouch in relation to the bony pelvis, which in turn indicates the relation to the levator ani muscle complex. 3 specific lines: 1) Pubococcygeal line (PCL) 2) Ischial line (I line) 3) Anal pit line
- A gas bubble situated above the PC line is designated “high” anomaly.
- One located between the PC and I line or point “Intermediate” anomaly.
- If it extends below the I line (point), then it is called “low” anomaly.
- Congenital anomalies of the spine (ie, sacral agenesis)
- Presence of gas in the region of urinary bladder and vagina, which would indicate an underlying fistula.
What is a sacral ratio?
A sacral ratio is an objective evaluation of the sacrum and can range from 0.0–1.0.
Line A: Most superior portion of iliac crests
Line B: Most inferior portion of sacroiliac joints
Line C: Line parallel to the preceding lines, at the most inferior point of the sacrum
Sacral ratio = BC/AB
The normal sacral ratio in children is 0.77.
Children with anorectal malformations have varying degrees of poor sacral development.
A ratio >0.7 is usually associated with good bowel control, whereas one <0.4 is associated with poor bowel function.
The sacral development seems to correlate with the development of the muscles and nerves of the pelvis, and therefore is a valuable objective measure of caudal regression.
How is a runner’s elbow used to depict levels of a rectourethral fistula?
Caudad to Cephalad
Elbow: Urethra-bulbar junction
Triceps: Urethra-prostatic junction
Shoulder: Bladderneck level
In neonates with imperforate anus, when the clinical information does not allow one to make a decision about the opening of a colostomy, the next most valuable study is:
A magnetic resonance imaging (MRI)
B CT scan
C invertogram
D cross-table lateral film with patient in prone position
E ultrasound.
D
A cross-table lateral film with the patient in prone position is a good tool to measure the distance between the distal rectum and the anal dimple, in order to decide whether a primary repair (air below the coccyx) or a colostomy (air above the coccyx) is appropriate.
In the past, invertograms were the exam of choice, but they were very uncomfortable for the patients and there was a risk of vomiting, aspiration and cyanosis.
The same information can be obtained with a cross-table lateral film.
SPSE 1
What is the diagnosis and what would be the best surgical approach for this patient?
A perineal fistula, dilatation of the fistula
B anal membrane, perforation of membrane
C no fistula, posterior sagittal anorectoplasty
D anal stenosis, dilatation of stenotic tract
E anterior mislocated anus, cutback
C
This high-pressure distal colostogram shows an anorectal malformation without fistula.
The distal rectum is very close (about 1–2 cm) from the anal dimple and it is also below the sacrum.
This is very similar to the location of a rectourethral bulbar fistula type of anorectal malformation.
With that image the surgeon can open posteriosagittally and the first structure that will be found will be the rectum.
With mobilisation of the rectum an anoplasty can be performed.
SPSE 1
What is the diagnosis and what would be the surgical approach for this patient?
A rectoprostatic fistula, posterior sagittal approach only
B no fistula, posterior sagittal approach only
C recto-bladder neck fistula, posterior sagittal approach only
D rectoprostatic fistula, laparotomy/ laparoscopy and posterior sagittal approach
E recto-bladder neck fistula, laparotomy/ laparoscopy and posterior sagittal approach
E
This high-pressure distal colostogram shows a recto-bladder neck fistula with plenty of distal bowel left for the pull-though.
The colon is above the sacrum (as always occurs in recto-bladder neck fistulas), so a laparotomy/laparoscopy will be needed in order to reach the rectum and mobilise it.
After the mobilisation, a small posterior sagittal incision and anoplasty is performed.
SPSE 1
What is the diagnosis and how would you approach this patient:
A recto-bladder neck, posterior sagittal approach
B rectoprostatic, posterior sagittal approach
C rectobulbar, posterior sagittal approach
D rectoprostatic, laparotomy/laparoscopy
E rectobulbar, laparotomy/laparoscopy
C
This high-pressure distal colostogram shows a rectobulbar fistula.
The rectum is below the sacrum and it can be reached by a posterior sagittal approach.
An important anatomical characteristic of this malformation is the fact that it is the one that shares the longest common wall with the urethra, and therefore it requires a meticulous surgical dissection.
SPSE 1
You are asked to examine the perineum of a newborn patient, your diagnosis is:
A imperforate anus, high malformation
B imperforate anus, unknown malformation
C rectobulbar fistula
D anorectal malformation without fistula
E perineal fistula.
E
Following the scrotal raphe down, one identifies a small orifice that corresponds to a perineal fistula in a male patient.
A careful physical exam is the key to making this diagnosis.
The surgeon can expect to find the healthy rectum within 1–2 cm of the fistulous tract.
During the surgical repair, the surgeon has to be particularly careful with the dissection plane between the rectum and urethra, since these two structures are closely related.
SPSE 1
What malformation is this?
A vestibular fistula
B rectovaginal fistula
C perineal fistula
D cloaca
E no fistula
A
This is a vestibular fistula, the most common anorectal defect in female patients.
The physical exam is key to making this diagnosis.
The most important anatomical feature during the surgical repair is the common wall between rectum and vagina that requires a very meticulous dissection to achieve separation.
SPSE 1
During the repair of a cloaca, with two hemivaginas, where must one look for the rectal orifice?
A in the right vagina
B in the left vagina
C on the posterior wall of the common channel
D in the septum that separates the two hemivaginas
E on the anterior wall of the common channel
D
In the presence of two hemivaginas in a patient with a cloaca, the rectum usually can be found opening in the septum between the two hemivaginas.
SPSE 1
What is an H-type fistula?
An H-type fistula is probably the rarest type of anorectal malformation in a girl, representing less than 1% of all anorectal anomalies.
In this type of malformation, the anus may be normal, ectopic, or stenotic. The fistula is found between the distal rectum or anal canal and the vagina, vaginal fourchette, or labia.
The hallmark symptom is passage of stool through the vagina. Recurrent labial abscesses are a more rare presentation.
Since the anus is normal in most cases, the diagnosis should be suspected purely on history. It is confirmed by a rectal and perineal examination under anesthesia since the fistula is usually small and very difficult to localize on physical examination.
If the history is reliable or stool is seen emanating from the vaginal introitus, localization of the fistula can be performed just prior to the repair.
Multiple procedures have been suggested for this anomaly. Mobilization, division, and ligation of the fistula, followed by a limited Swenson procedure to cover the repair with healthy rectal wall, result in a low rate of recurrence.
Although not uniformly recommended, a temporary diverting colostomy should be strongly considered.
Figure 41.11 shows the findings and repair of an H-type rectovestibular fistula in a 6-week-old girl who presented with recurrent stooling through the vaginal orifice. Temporary diversion for 2 months with a loop sigmoid colostomy, performed through an infraumbilical incision, resulted in an excellent outcome.
Sherif
How do you manage a cloaca <3cm?
Cloacas with a Common Channel Shorter than 3 cm
The incision extends from the middle portion of the sacrum down to the single perineal orifice. The sphincter mechanism is divided in the midline.
The first structure that the surgeon will find after division of the sphincter mechanism is the rectum. The rectum is opened in the midline, and silk stitches are placed along the edges of the posterior rectal wall.
The incision is extended distally through the posterior wall of the common channel. The entire common channel is exposed to allow confirmation of its length under direct vision.
The rectum is then separated from the vagina. This is performed in the same way as for repair of a rectovestibular fistula because the rectum and vagina share the same common wall already described. In patients with a vaginal septum, the rectum must be searched for at the posterior aspect of this septum.
Once the rectum has been completely separated from the vagina, a maneuver called total urogenital mobilization is used. Before this advance, the vagina was separated from the urinary tract, which was a technically challenging maneuver associated with significant morbidity.
Total urogenital mobilization consists of mobilization of both the vagina and urethra as a unit without separating them. After the rectum has been separated, multiple silk stitches are placed through the edges of the vagina and the common channel to apply uniform traction on the urogenital sinus. Another series of fine stitches are placed across the urogenital sinus approximately 5 mm proximal to the clitoris. The urogenital sinus is transected between the last row of silk stitches and the clitoris.
The dissection takes advantage of the fact that there is a natural plane of separation from the pubis. Rapidly and in a bloodless field, one can reach the upper edge of the pubis. There, a fibrous, avascular structure that gives support to the vagina and bladder is identified.
This structure is called the suspensory ligament of the urethra and bladder. This ligament is divided, which immediately provides significant mobilization (between 2 and 3 cm) of the urogenital complex. One can then dissect the lateral and dorsal walls of the vagina to gain an extra 5 to 10 mm.
This dissection is enough to repair about 60% of all cloacas and is a reproducible maneuver. It has the additional advantage of preserving an excellent blood supply to both the urethra and vagina. It places the urethral opening in a visible location and provides a smooth urethra that can easily be catheterized.
What used to be the common channel is divided in the midline to form two lateral flaps that are sutured to the skin to create the new labia.
If a vaginal septum is present, it is removed. The vaginal edges are then mobilized to reach the skin to create the introitus. The limits of the sphincter are electrically determined.
The perineal body is reconstructed by bringing together the anterior limit of the sphincter.
The rectum is placed within the limits of the sphincter in the manner previously described.
Patients can eat the same day, and the pain is usually easily controlled. Patients are discharged 48 hours postoperatively.
Coran
Which patients are candidates for the vaginal switch maneuver?
A specific group of patients are born with hydrocolpos and two hemivaginas. The hemivaginas are large and the two hemiuteri are separated, the distance between them being longer than the vertical length of both hemivaginas.
In these cases it is ideal to perform a maneuver called a “vaginal switch” (Fig. 103-23).
One of the hemiuteri and the ipsilateral fallopian tube is resected with particular care taken to preserve the blood supply of the ovary.
The blood supply of the hemivagina of that particular side is sacrificed.
The blood supply of the contralateral hemivagina is preserved and provides for both hemivaginas.
The vaginal septum is resected, and both hemivaginas are tubularized into a single vagina by taking advantage of the long lateral dimension of both hemivaginas.
Then, what used to be the dome of the hemivagina where the hemiuterus was resected is turned down to the perineum.
This is a useful maneuver that can be performed only when these specific anatomic characteristics are encountered.
Coran
Which patients are candidates for vaginal replacement?
In a patient with a small vagina(s) or in the rare case of an absent vagina, a vaginal replacement is required. In such cases the choices are rectum, colon, or small bowel.
When the patient has internal genitalia or an upper blind vagina, the upper part of the bowel used for replacement should be sutured to the vaginal cuff.
When the patient has no internal genitalia (no vagina and no uterus), a vagina is created and left with its upper portion blind and used only for sexual purposes.
Rectum: This form of vaginal replacement is feasible only in patients who have a good size rectum that is large enough to be able to divide it transversely or longitudinally into a portion with its own blood supply that will form a new vagina and another portion with enough circumference to reconstruct an adequately sized rectum.
The blood supply of the rectum will be provided transmurally from branches of the inferior mesenteric vessels. This can also work for patients with a rectosigmoid long enough to allow the distal portion to be used as a new vagina with its own blood supply and the upper portion to be pulled down as the new rectum.
Colon: The colon is an ideal substitute to replace the vagina. However, sometimes the location of the colostomy interferes with this type of reconstruction.
The left colon or sigmoid work well because their arcades reach the perineum nicely. Sometimes taking the colostomy down and using its distal segment for the vaginal graft is a helpful maneuver.
Small Bowel: When the colon is not available, the most mobile portion of the small bowel is used for vaginal reconstruction. The mesentery of the small bowel is longest in an area located approximately 15 cm proximal to the ileocecal valve, which is the best portion of the small bowel for vaginal replacement. A portion of the ileum is isolated and pulled down while preserving its blood supply.
In the highest type of cloaca one may find two little hemivaginas attached to the bladder neck or even to the trigone of the bladder. In these cases the rectum also opens in the trigone.
Separation of these structures is done abdominally. Unfortunately, when the separation is completed, the patient is frequently left with either no bladder neck or a severely damaged one.
At that point the surgeon must have enough experience to make a decision whether to reconstruct the bladder neck or close it permanently.
In the first situation, most patients will require intermittent catheterization to empty the bladder. A vesicostomy is created in such cases, and the patient will require a continent diversion type of procedure and possibly a bladder neck procedure and/or bladder augmentation, done at the age of urinary continence (3 to 4 years old). In this particular type of malformation, the patient usually also needs a vaginal replacement, which should be performed in one of the ways previously described.
At the time of colostomy closure, endoscopy should be performed to be sure that the repair is intact and that there is no prolapse, stricture, or urethrovaginal fistula. If the cloaca repair did not require laparotomy, the time of colostomy closure is the opportunity to investigate the patency of the mullerian structures.
Coran
