Keywords anorectal malformation - cloaca - rectovaginal fistula - cloacagram - imperforate
anus
New Insights and the Importance for the Pediatric Surgeon
Multimodal imaging allowed for delineation of the postoperative anatomy of a cloacal
repair presenting with a complication, and formulation of a plan for a reconstructive
strategy to ensure a repair that maximized the patient's potential for fecal continence
as well as gynecologic function. This case is an important reminder of the need for
correct and comprehensive preoperative imaging and anatomical evaluation prior to
performing a reconstruction for an anorectal malformation.
Introduction
Anorectal malformations (ARMs) can have a wide spectrum of anatomic complexity, and
clear preoperative imaging is key to planning and executing an anatomic reconstruction.
Common postoperative complications of ARM repair include rectal prolapse, remnant
of the original fistula, anal or rectal stricture, wound dehiscence, and recurrent
fistula.[1 ] A cloacal malformation is characterized by a single perineal orifice in which the
urologic, gynecologic, and gastrointestinal tracts meet. It represents one of the
most complex congenital anomalies of the pelvic organs in females, with an incidence
of 1 in 50,000 births.[2 ]
[3 ]
[4 ] In 30 to 70% of nonsyndromic patients with ARMs, a combination of congenital anomalies
of multiple systems known as the VACTERL (V—vertebral, A—anorectal, C—cardiac, TE—tracheoesophageal,
R—renal, L—limb) association is present. The diagnosis of VACTERL association requires
that three or more of these conditions are present.[5 ]
[6 ]
[7 ]
Case Report
A 10-month-old female was referred to our center for an anal stricture. She was diagnosed
as an infant with a short channel cloaca. After initial colostomy and mucous fistula
creation, she underwent a posterior sagittal anorectoplasty at an academic children's
medical institution, with mobilization of what was thought to be the rectum. She reportedly
did not require any surgical correction of the genitourinary sinus component of her
cloaca.
On our exam, the urethral meatus was hypospadic, 0.5 cm inferior to the convergence
of the corpora. Cystoscopy showed a normal urethra and bladder, but we could not identify
the vagina. The perineum had an opening within the muscle sphincter complex, previously
described as the anus that was severely strictured for a length of 1.5 cm, accommodating
only a size 4 Hegar dilator.
A distal colostogram ([Fig. 1 ]) showed that the vagina had been mistaken for the rectum and had been pulled through
as the “anoplasty.” The original rectum ended in a high rectovaginal fistula above
the pubococcygeal line, which had not previously been recognized or repaired. Three-dimensional
imaging confirmed these findings and showed an accessory anterior urethra ([Fig. 2 ]). Additional urologic anomalies included a malrotated left kidney and mild bilateral
hydronephrosis. Her sacral X-rays demonstrated three sacral elements with fusion of
the lower elements and a lateral sacral ratio of 0.72. A spinal magnetic resonance
imaging was obtained showing her conus medullaris terminating at the upper end of
L3, and the neurosurgeon's review determined the cord was not tethered.
Fig. 1 A distal colostogram with structures labeled. The two dots represent the urethral
orifice anteriorly and the anoplasty location posteriorly.
Fig. 2 Three-dimensional cloacagram, which is rotatable, showing more detail and noting
an accessory urethra anterior to the bladder, labeled here.
Based on our preoperative studies, we started the surgical reconstruction with a laparoscopic
mobilization of the rectum and dissected out the rectovaginal fistula but left it
attached to the posterior vagina. Inspection of the pelvis revealed an atretic hemiuterus
on the left side, which was resected with the Fallopian tube, while preserving the
left ovary. The right side had normal anatomy. After sufficient length on the rectum
was obtained, the patient was then positioned prone. Via a posterior sagittal incision,
a full-thickness mobilization of the native vagina around the “anoplasty” was performed.
The vagina, once mobilized, was then placed at the introitus abutting the posterior
urethra and urethral meatus. The rectum was detached from the back of the vagina,
mobilized, and brought down into the anal muscle complex to create the anoplasty.
The perineal body was then reconstructed. The orthotopic urethral meatus was visible,
allowed for easy catheterization, and did not require any mobilization. The accessory
urethra appeared blind ending, as it approached the glans clitoris. This will be observed
with consideration of excision if clinically symptomatic.
Discussion
Evaluation of an ARM patient who is not doing well postrepair starts with obtaining
a detailed history including symptoms, current and past medical therapies, and surgical
interventions.[8 ] This patient was referred for anal stricture, which occurs in 20 to 30% of ARMs.[9 ] A review of 95 redo operations in cloaca by this paper's senior author showed that
the most common indication for revision was a persistent urogenital sinus in which
the rectal component only was repaired (46), followed by a rectal stricture or atresia
(45), acquired vaginal stricture or atresia (45) mislocated rectum (36), urethrovaginal
fistula (16), rectal prolapse (12), urethral atresia or stricture (7), and rectovaginal
fistula (5), with most patients having greater than one indication.[10 ] The first challenge in reducing complications of cloacal repair is to determine
the complexity of the malformation before embarking on the repair. To optimize the
functional result, a key part of the evaluation is to confirm that the anatomy has
been correctly reconstructed.
At our institution, endoscopy is routinely performed for patients with complex malformations
to understand the anatomy of the bladder, ureters, urethra, vagina(s), and common
channel (in the case of a cloaca), as well as to visualize the location and height
of the distal rectum. Anomalies of the genital tract such as a vaginal septum, bicornuate
uterus, or uterine didelphys may be diagnosed.
Three-dimensional reconstructed fluoroscopy or cloacagram is performed to obtain the
lengths of the common channel and urethra and to assess spatial relations of the rectal
fistula and other structures relative to the pelvis.[11 ] In the initial surgical repair of this patient, it is likely that the first structure
dissected during the posterior sagittal incision was believed to have been the rectum,
located at the vestibule, instead of correctly identifying that structure as the vagina.
Our imaging showed the location of the original rectum to be above the pubococcygeal
line, making the posterior sagittal approach of the rectal dissection exceedingly
difficult, and an initial laparoscopic mobilization preferred. The distal rectum and
fistula may not have been clearly delineated on the original preoperative colostogram,
contributing to this misidentification. A true rectovaginal fistula is exceedingly
rare and a cloacal malformation should be suspected in a female patient with imperforate
anus without a clear vestibular or perineal fistula, and without a normal urethral
orifice. Preoperative planning with a multidisciplinary approach, including endoscopy
and multimodal imaging, is vital to achieve the successful, definitive anatomic repair
of ARMs.
Two months after her reoperation, this patient's colostomy was closed. At her follow-up
appointment 9 months postoperatively, she was experiencing mild constipation, which
was well managed with stimulant and mechanical laxatives.
Conclusion
This case demonstrates a rare complication that occurred during what was thought to
be a cloacal reconstruction in which the vagina was pulled through as the anoplasty.
Multimodal imaging allowed us to delineate the anatomy and plan a successful reconstructive
strategy to ensure a repair that maximized the patient's potential for fecal continence
as well as gynecologic function. This case is an important reminder of the need for
correct and comprehensive preoperative imaging and anatomical evaluation prior to
performing a reconstruction for an ARM.
