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APSP J Case Rep 2011; Vol. 2 (1)
Tripus Conjoined Twins
Department of Pediatric Surgery, National Institute of
Child Health Karachi, Pakistan
*Corresponding Author's E-mail address:
APSP J Case Rep
2011; 2: 5
Competing Interest: None
A conjoined twin is one of the rare
congenital defects. Ischiopagus variety is even rarer. We present a case of
ischiopagus-tripus conjoined twins. They were fused at the lower halves of the
bodies. One of the twins was apparently normal looking, active and pink. The
other twin was small, ill looking, sluggish and cyanosed. There were two well
formed separate lower limbs on one side and a fused limb at the other side. The
twins had an imperforate anus and two small orifices draining urine with
incompletely developed external genitalia. Pre-operative workup was in progress
when the twins passed away.
Conjoined Twins, Ischiopagus, Tripus,
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Ischiopagus tripus conjoined twins. APSP J Case Rep 2011;
Conjoined twins represent one of the
rarest congenital anomalies occurring with a varying incidence of about
1:50,000-1:200,000 births approximately. Females predominate over males in the
order of 2:1 to 3:1. Ischiopagus conjoined twinning is even rarer representing
only 6% of all conjoined twins. Because of the highly variable and complex
anatomy and associated malformations, skilled clinical assessment aided by
detailed radiological studies, appropriate planning and team work are required
for the successful separation of the conjoined twins [1-4]. We present here a
case of ischiopagus tripus conjoined twins who passed away while being
Full term conjoined twins, weighing 4000 grams, were brought to
our hospital at 3rd hour of life. They were delivered by emergency
cesarean section, to a 32 years old lady, already having 8 children. There was
no family history of twinning. Ante-natal ultrasound was done only once 4 days
prior to delivery. It showed twin alive pregnancy of 38 weeks ± 01 week with
cephalic presentation and adequate liquor with no comments on
The twins were fused at the lower halves of their bodies with
a single umbilicus at the mid. There was a horizontal scar of about 3 ˝ cm
extending to the right of umbilicus. The healthier looking active pink neonate,
termed Twin A, had normal head, neck and upper limbs. There was gradual
broadening of the torso above umbilicus. The smaller neonate, termed Twin B, was
a thin, emaciated, cyanosed, microcephalic neonate, with small torso and feeble
reflexes. There were two separate lower limbs at the left side of Twin A and a
fused lower limb at the right side. The anal orifice was absent and two orifices
were found in perineum draining urine. Umbilicus had a single set of umbilical
vessels. External genitalia were incompletely developed to assign gender to
either neonate. Cardiac murmur was audible on auscultation in both the twins
(Fig. 1 & 2).
X-ray babygram revealed fusion at the lower
abdomino-pelvic region. Scoliosis of dorsolumbar spine noted in both neonates,
which was more marked in the Twin B. Pubic symphyses were widely separated and
ischio-pubic bones were deformed on the right side with sacral dysgenesis of
Twin B. The hip joints were abnormally oriented and horizontally oriented femora
were attached to a large pelvic ring bilaterally. On one side, there was
synostosis of femora. Calvarial defect with torticollis was present in Twin B
Ultrasound abdomen examination of Twin A showed hydronephrosis
and hydroureter on both the sides while rest of the viscera were normal. In the
Twin B, spleen and the left kidney were well formed but other viscera could not
be clearly visualized. There was a large anechoic cystic structure in the pelvis
representing bladder. Cystogram performed via the two small orifices in the
perineum revealed non-visualization of urethra with pooling of contrast in the
single reservoir representing shared urinary bladder. (Fig. 4)
revealed moderate hydronephrosis bilaterally in both babies. In Twin B there was
lack of visualization of other viscera. Normal lung and mediastinum were also
not seen in Twin B who also had small skull, deformed and devoid of normal brain
tissue, replaced by a cystic space. The Twin A showed normal thoraco-abdominal
viscera bilaterally. Multiple prominent cystic areas were noted in the centre
likely representing bowel loops. There was failure to identify separate urinary
bladders. Because of the limited multi-dimensional views of MRI, internal
genitalia were not appreciable. (Fig.5)
On the second day of life,
sigmoid loop colostomy was made under local anesthesia through the already
present scar on the abdomen. The peritoneal cavity was not explored. The stoma
started functioning following day and the Twin A was allowed top feed via
nasogastric tube that was tolerated. The clinical condition of the Twin B
remained critical throughout with feeble reflexes, abnormal breathing patterns
and oxygen desaturation most of the times. Twin B who later died following which
Twin A’s condition also deteriorated but he also passed away within few hours on
the 6th post-operative day.
Conjoined twin is a rare developmental defect; the exact
cause of which is still obscure. Some authorities consider it as a result of
incomplete division of the embryonic disc, while others are of the view that
there is secondary fusion of two originally separate monozygotic embryonic discs
Various classification systems have been proposed for this defect.
Spencer classified conjoined twins on the basis of site of union i.e.: ventral
or anterior union (cephalopagus, thoracopagus, omphalopagus, ischiopagus, and
parapagus) and dorsal or posterior union (craniopagus, pyopagus, and
rachipagus), while Potter and Craig simply classified on the basis of most
common forms of twinning [6,7].
Ischiopagus conjoined twinning considered
the most complicated form, accounts only for 6% of the cases.
Grossly, ischiopagus usually lie along a long axis with heads on opposite
sides. They have a common umbilicus and the bodies fuse below this level,
sharing lower abdomen and pelvis. About half of the ischiopagus have four
separate lower limbs, 1/3rd have 3 lower limbs (2 separate and 1
fused) attached to the body laterally and 1/5th cases are parasitic
[1-4]. Our case, therefore, is an example of ischiopagus tripus variety.
Radiologically, there was synostosis of the femora on the right side of Twin A.
(Fig.2). It is reported that one of the twins is almost always weaker or
smaller, though genetically identical and may have additional congenital defects
. This was also noted in this case as the Twin B was very small, weak and
microcephalic with scoliosis of dorsolumbar spine and sacral dysgenesis.
Calvarial defect, torticollis and absence of normal brain tissue were also
The internal organs shared by ischiopagus conjoined twins are
usually the liver, lower gastrointestinal tract (GIT) and genitor-urinary
organs. The GIT sharing in ischiopagus twins is usually ileo-colic, having union
at the terminal ileum (at Meckel’s diverticulum) with shared bowel distally or
rarely the sharing is only colonic. The rectum and the anus may be single or
imperforated. Obstructed GI or genitourinary tract, ruptured
omphalocele, severe respiratory distress or cardiac failure in one of the twins,
are some of the indications which may require emergency surgery [1,2,5,8].
It is well known fact that the fetal wounds heal without scar formation.
The true mechanism of the scarless fetal tissues repair is not known . The
linear healing wound or scar at the right side of umbilicus in our patient could
not be explained according to this theory. This scar was also the line of
vascular perfusion demarcation between the twins frequently noted when Twin B
used to desaturate.
About 51% of the ischiopagus twins have shared
pelvic organs. Urinary bladder may be single or double, lying side by side or
combined with one bladder draining into the other . In this case, the twins
had two perineal openings which were draining urine with single urinary bladder
as noted on cystogram, ultrasound abdomen and MRI.
Diagnostic workup also
includes skeletal surveys, ultrasonography, contrast imaging of the
gastrointestinal and urinary systems, endoscopy, computed tomography and MRI.
Angiography and radio-isotope liver and renal scans may provide with further
details. Complete cardiac evaluation ought to be done in ischiopagus, as there
is high incidence of associated congenital cardiac anomalies in all variants of
conjoined twins [1,3,5]. We employed many of these investigations for complete
delineation of external and internal structures, and to detect associated
anomalies in order to plan separation but unfortunately twins died during the
course of hospital stay.
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