Keywords anorectal malformation - imperforate anus - Mullerian anomalies - vestibular fistula
- vaginal atresia
Case Report
A full-term newborn has an imperforate anus, thought to be a rectovestibular fistula.
The baby was taken to the operating room on the first day of life with the plan for
primary repair of the rectal anomaly via a posterior sagittal anorectoplasty (PSARP).
A more careful physical exam in the operating room, however, identified an unexpected
finding. This prompted the decision to proceed with a diagnostic laparoscopy instead
of definitive surgery. Images from the physical exam and the diagnostic laparoscopy
are shown in [Fig. 1A ].
Fig. 1 (A ) Physical exam showing meconium passing through posterior portion of introitus, with
no vaginal orifice in location expected. (B ) Diagnostic laparoscopy showing a left atretic fallopian tube with intact ovary.
(C ) Diagnostic laparoscopy showing an intact right fallopian tube with intact ovary.
a. Urethra. b. Introitus. c. Rectum. d. Left atretic Mullerian system. e. Right obstructed
vagina. f. Right patent uterus. g. Right patent fallopian tube.
Discussion
Newborn females with an ARM may present with several anatomic variations. These include
perineal fistula, rectovestibular fistula, isolated imperforate anus without fistula,
or cloaca.[1 ] A thorough physical exam in the first 24 hours of life is crucial to identify which
anatomic variant of ARM is present. The passing of meconium through a location outside
of the sphincter complex signals the presence of a fistula.
In the case presented, examination of the patient revealed meconium passing from an
orifice appearing to be within the introitus (see [Fig. 1A ]). While this was initially presumed to be a typical rectovestibular fistula, with
the opening of the rectal fistula abutting the hymen but within the introitus, a more
careful examination in the operating room demonstrated the presence of a rectal fistula
within the posterior fourchette of the vulva and the absence of a vaginal opening.
After discussion with the family, the decision was made to proceed with a diagnostic
laparoscopy to better understand the anatomy and plan for future intervention. Diagnostic
laparoscopy revealed an atretic left Mullerian system with the presence of a truncated
left fallopian tube and no discernable left uterine, cervical, or vaginal structures,
and what appeared to be a developed right Mullerian system including right uterine
horn, palpable cervix, and a mildly distended vaginal canal (see [Fig. 1A–C ]). Together, the external examination and laparoscopic findings indicated the presence
of distal vaginal atresia on the right with atretic structures on the left (see [Fig. 2 ]).
Fig. 2
Left Image. A schematic drawing of [Fig. 1 ], with the perspective of looking into the pelvis from a cephalad (bottom border)
to caudal (top border) perspective. Right Image . Inverted diagram showing cephalad (top border) to caudal (bottom border) orientation.
d. Left atretic Mullerian system. e. Right obstructed vagina. f. Right patent uterus.
g. Right patent fallopian tube.
While rectovestibular fistulas are the most common variant of ARM in newborn females,[1 ] the combination of distal vaginal atresia and rectovestibular fistula is a rare
occurrence. It is important for surgeons to be aware of this defect as it is often
misdiagnosed and incorrectly treated.[2 ] The presence of distal vaginal atresia in these cases often goes unrecognized, as
the orifice through which meconium passes is presumed to be the typical rectovestibular
fistula and the lack of an introitus is not recognized.[2 ] Sometimes confusion arises when the surgeon attempts a primary repair with PSARP,
identifies the rectum, and is then unable to find the vagina. But more often, the
vaginal anomaly is not noted and only discovered at puberty when the patient presents
with amenorrhea or cyclic pelvic pain. Others may mistake the rectal fistula for the
vagina, which leads to difficulty in identifying the rectum.[2 ]
In any of these situations, dissection of the space between the rectum and urethra
can create scar tissue that will make any subsequent reconstruction more challenging.[2 ] This makes identification of this anomaly prior to any surgical repair extremely
important. All options for gynecologic intervention need to be considered, including
the possibility of a vaginal pull-through if an upper vagina is present, need for
vaginal replacement if appropriate, or the potential for future dilations of the introitus
if there are no intraabdominal Mullerian structures (similar to the internal anatomy
of a patient with Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome).
On the initial physical exam, it is prudent for the physician to identify both the
number of orifices and their location relative to proper anatomic landmarks.[1 ]
[3 ] In both the case of a rectovestibular fistula and of an accompanying atretic or
absent vagina, two orifices will be found on physical exam—the urethra and fistula.
If a vaginal orifice cannot be identified, this should prompt a diagnostic laparoscopy[3 ] so that the intraabdominal Mullerian anatomy can be ascertained. While this does
not need to be done immediately in the neonatal period, it should be done prior to
a planned repair. In all cases of rectovestibular fistula, even when a vaginal opening
is identified, a careful inspection of the introitus, and even vaginoscopy, is appropriate
to be certain that the vaginal anatomy is typical. When anomalies are noted in patients
with rectovestibular fistula and patent vaginal openings, the most common finding
is a vaginal septum, which also may need to be repaired, either at the time of the
anorectal repair or at puberty.[2 ]
There are multiple options for surgical reconstruction when presented with a rectovestibular
fistula and an absent or atretic vagina. One strategy is to leave the distal rectum
as the neovagina and mobilize the proximal rectum through the anal sphincter to create
the neorectum. This minimizes the possibility of injury to the urethra by preventing
extensive dissection of the common wall of the urethra and rectum.[4 ] Also, the distal rectum often lies exactly where the introitus belongs, making this
option tempting. The neovagina can be anastomosed to the remnant upper vagina if one
exists. Anastomosing it to the uterus if there is no cervix is incorrect as that can
lead to ascending infections. In such a rare case, a hysterectomy is warranted.[3 ]
The main problem with leaving the distal rectum to become the neovagina, however,
is the loss of the rectal reservoir, which can have negative implications on bowel
control. The benefit of using the native rectum in the anorectoplasty is the preservation
of the rectal reservoir as well as any inherent sensory or proprioceptive function
the distal rectum may provide.[2 ] This is why it is advised in a patient with good potential for achieving bowel control
(a patient with a normal sacrum, good pelvic muscles, and no associated spinal anomaly)
to keep the distal rectum as rectum as one would for a typical vestibular fistula
case. In this case, since the patient had a normal sacrum with a lateral sacral ratio
greater than 0.7 cm, this approach of mobilizing the distal rectum into the sphincter
complex was taken to maximize bowel control potential.
When using the native rectum for the anorectoplasty, the separation of the distal
rectum from the urethra is needed—this plane is thicker than the one that surgeons
are used to when they separate the rectum from the posterior vaginal wall. When a
vaginal pull-through is not feasible, vaginal reconstruction can be done with a segment
of colon or small bowel. While colon is preferred for use as vaginal replacement due
to its abundant blood supply, the ileum has also been used to create a neovagina.[2 ]
[3 ] Another option is to wait to complete the vaginal repair till after puberty, with
the potential that the distal atretic vagina will be longer and be more easily mobilized
to reach the perineum for a pull-through. If there are no intraabdominal Mullerian
structure and the introitus is adequate, the introitus could be dilated later in life.[2 ]
[3 ]
[4 ]
Given that the patient in this case has a unicornuate uterus and the presence of proximal
vagina on the right side (a rare finding), a vaginal pull-through is a viable option
(see [Fig. 3 ]). While we were prepared to do a bowel neovagina if necessary, the patient's native
vaginal reached quite nicely. This approach alleviates the obstruction of Mullerian
structures on this side, allowing for menstrual egress and preserving reproductive
capacity while also avoiding the need for vaginal replacement. The left atretic and
nonpatent Mullerian structures can be excised; however, observation with pelvic ultrasound
throughout puberty to ensure there is no accumulation of hematocolpos would also be
appropriate if excision is not completed. If the atretic structures are removed, the
left Fallopian tube should be removed as well, as this intervention helps reduce the
risk of ovarian cancer.[5 ]
Fig. 3 Due to an intact right-sided uterus and vagina, the vagina can be mobilized to the
introitus via a pull-through (A ), while the distal rectum is mobilized and reinserted into the anal sphincter through
a posterior sagittal anorectoplasty (B ).
Most of the available literature advocates for vaginal repair at the same time as
ARM repair, especially if both are noted in the newborn period. This is because the
ARM repair involves dissection of the introitus and perineal body, so a future vaginal
replacement would be more difficult given accumulation of postoperative scarring.
It is important to consider ethical implications of the decisions regarding vaginal
replacement in infants—or any patient unable to participate in informed consent—given
that vaginal replacement involves alteration of anatomy linked to sexual identity
as well as function. Such ethical implications have been routinely evaluated in patients
with differences in sexual development,[6 ] favoring postponement of nonurgent surgical alteration of the genital tract until
a patient is capable of, at minimum, assent. While these ethical considerations remain
important in patients with ARMs requiring vaginal pull-through or vaginal replacement
procedures, it is also important to weigh risks of delay in these procedures. These
risks include development of menstrual obstruction at puberty and potential surgical
complications associated with performance of vaginal pull-through or replacement procedure
after anorectoplasty has been performed. Notably, there are reported cases of vaginal
reconstruction done later in life in patients who were not diagnosed with vaginal
atresia or agenesis until adolescence, with good outcomes in urinary and stool continence.[7 ]
In addition, such patients need to be specifically evaluated for associated urologic
issues as patients with this specific ARM type tend to have associated urologic problems,
similar to those found in the MRKH complex. As with all patients born with imperforate
anus, it is important to inspect for other anatomic anomalies associated with VACTERL
(Vertebral defects, Anal atresia, Cardiac defects, Tracheoesophageal fistula, Renal
anomalies, and Limb abnormalities). The patient in this case had no other associated
VACTERL or urological anomalies.
Conclusion
Rectovestibular fistulas are the most common ARM in females. Patients with rectovestibular
fistulas may also present with Mullerian abnormalities, and although rare, Mullerian
anomalies may include distal vaginal atresia. In these circumstances, the newborn
physical exam will reveal two orifices in the perineum and absence of vaginal opening.[2 ]
[7 ] Upon closer inspection, however, a vaginal orifice can be differentiated from a
rectal orifice depending on the location of the opening relative to the introitus
in the vaginal vestibule.[2 ] Atypical vaginal anatomy, particularly when a vaginal opening cannot be located,
should prompt a diagnostic laparoscopy to delineate gynecologic anatomy prior to ARM
primary repair. Early identification of gynecologic anomalies allows for gynecological
reconstruction at the same time as the primary ARM repair.
