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Dicephalus dipus dibrachius: An unusual case of conjoined twins
Dicephalus
Dipus
Dibrachius:
By Jonathan
I. Groner,
An Unusual
Douglas W. Teske, and Steven Columbus, Ohio
l Conjoined twinning is a rare anomaly, occurring in one of every 50,000 births. Dicephalus dipus dibrachius is an extremely rare form of conjoined twinning in which the infant has two arms, two legs, one trunk, but two heads. These infants are often stillborn or die shortly after birth. The authors describe a case of dicephalus twinning with ll-day survival. A thorough investigation using multiple imaging modalities (plain radiographs, contrast studies, ultrasonography, and magnetic resonance imaging) demonstrated that these twins had separate spinal columns but shared multiple internal organs including heart, liver, pancreas, intestine and bladder. Based on the anatomy of this case, the authors conclude that separation of dicephalus dipus dibrachius twins should not be attempted. Copyright o 1996by W.B. Saunders Company
INDEX chius.
WORDS:
Conjoined
twins,
dicephalus
dipus
Case of Conjoined
dibra-
HE INCIDENCE of conjoined twinning is most often stated as 1 in 50,000 births. Because the majority of conjoined infants are stillborn, the true incidence of liveborn conjoined twins is approximately one in 200,OOO.r Thoracopagus accounts for 40% of conjoined twinning, omphalopagus, 33%; pyopagus (joined at the sacrum), 19%; ischiopagus, 6%; and craniopagus, 2%. Dicephalus dipus dibrachius is a rare form of twinning in which the children have two heads but only two arms, two legs, and one torso. This anomaly is so unusual, and survival is so limited, that it is not included in many review articles. We report a case of dicephalus dipus dibrachius twins that survived 11 days and underwent an extensive clinical evaluation.
T
CASE REPORT
Twins
Teich
On physical examination, the twins were pink and active, but the left twin appeared to be making a stronger respiratory effort. Their heads were normocephalic except for indentations where they were in contact. Both heads had soft fontanelles, normal appearing eyes, patent ear canals and nares, and intact palates. The heart rate was 138 beats per minute with a regular rhythm and a holosystolic hum and a split Sl. Breath sounds were clear but the right infant was occasionally apneic. Mild intercostal retractions were observed. The abdomen was soft and not distended with a single umbilical cord containing two arteries and one vein. Examination of the external genitalia showed a single vagina that split posteriorly. A skin dimple was noted on the left side of the perineum without a patent anus. On the right side, there was a patent anus with meconium present. Two spines were palpable, but only one pelvis. Each extremity had five digits and appeared normal, except for wide spacing between the first and second toes of both feet. On neurological examination, all extremities moved spontaneously. Painful stimuli to the left arm or leg caused the left face to grimace, stimulation of the right arm or leg caused the right twin to respond.
Radiographic Studies Plain radiographs showed two thoracic cavities and two separate vertebral columns ending in paired sacral structures that were attached to a single, widely flared pelvis (Fig 2). Above the diaphragm, a spherical density between the two spines appeared to be a shared heart. With abdominal ultrasonography, one liver was seen in the middle of the upper abdominal cavity, one gallbladder, one pancreas, two kidneys (with a possible partial duplication of the left kidney), and a single bladder were seen. There was no evidence of obstructive uropathy. A magnetic resonance imaging (MRI) scan was performed but, because of motion artifact from the infants’ tachypnea, it added little new information. Under fluoroscopy, barium was instilled into the stomach of the left twin via a feeding tube. The contrast material passed into the duodenum and jejunum, then refluxed into the right twin’s duodenum and stomach, demonstrating a duplication of the upper intestinal tract. The barium then filled the remainder of the small bowel and emptied into a normally rotated and normal appearing colon and rectum (Fig 3).
The twins weighed 4.4 kg at birth, which followed an uncomplicated 38-week pregnancy in a 21-year-old gravida 1 woman who had obtained prenatal care. Three ultrasound examinations did not disclose any abnormalities. A cesarean section was performed electively because of breech presentation. Apgar scores were 1 and 9. The twins were noted to have two arms, two legs, one torso, but two heads and two necks (Fig 1). Each infant received 100% oxygen by face mask for a short time. A peripheral intravenous line was started; they were placed in 50% oxygen by face mask, and transported to Columbus Children’s Hospital.
From the Departments of tal, Columbus, OH. Address reprint requests to St, Suite 6C, Columbus, OH Copyright 0 1996 by W. B. 0022-3468/96/3112-0025$03.00/O 1698
Surgery Jonathan 43205. Saunders
and Pediatrics, I. Gronev,
Children’s MD,
Hospi-
555 South
18th
Company Fig 1.
JournalofPediatric
Dicephalus
Surgery,
dipus
Vol31,
dibrachius
conjoined
No 12 (December),
twins.
1996: pp 1698-1700
DICEPHALUS
DIPUS
1699
DIBRACHIUS
Echocardiographic Studies Real-time, two-dimensional echocardiography revealed a single heart with complex anatomy. An inferior vena cava was associated with each twin’s spine. These emptied into a common systemic venous atrium in the midline. There were bilateral atria1 septae, and each side had a fossa ovalis. The left twin had two atrroventricular valves. a pulmonary venous atrium; and two ventricles with normally related great arteries. The right twin had a pulmonary venous atrium and a single atrioventricular valve leading to a single ventricular chamber that functioned as a double outlet right ventricle (Fig 4). The right aorta was smaller caliber than the left one and persistent arterial duct shunting was present bilaterally.
Hospital Course The infants were given oxygen by nasal cannula (.5 Limin). and gavage feedings were split between the two infants, which they tolerated well. The twins were felt to be inseparable from a surgical standpoint and, because of their poor prognosis, a “do not resuscitate” order was written. On day 11, the babies were electively weaned off oxygen in preparation for possible discharge. Later that day, they became lethargic and a cardiac gallop was noted intermittently. A few hours later they developed apnea and bradycardia and died. Permission for autopsy was denied. The suspected cause of death was congestive heart failure. Fig 2. Radiogram columns and a single
of conjoined pelvis.
twins
demonstrating
paired
spinal
Ant t
Fig 3. Gastrointestinal contrast Barium instilled in the left stomach
radiography of conjoined twins. refluxes into the right stomach.
Fig 4. (A) Echocardiogram, and (B) schematic of cardiac anatomy of the conjoined twins. A, left twin’s pulmonary atrium; LTLV. left twin’s left Ventricle; LTRV, left twin’s right ventricle; MV, left twin’s mitral valve; RTRV, right twin’s double outlet right ventricle.
1700
GRONER,
DISCUSSION
Conjoined twinning occurs in 1 of every 50,000 to 60,000 births, but 60% of affected infants do not survive. Dicephalus dipus dibrachius is one of the least frequent variants of conjoined twinning.l The cause of dicephalus twinning is unknown, and there are no known risk factors that are specific to this anomaly. One case of dicephalus twinning was associated with maternal exposure to radiation from the 1986 nuclear reactor accident in Chernobyl.2 The diagnosis of dicephalus twinning has been made on prenatal ultrasound exam.3 In one case, an
TESKE,
AND
TEICH
ultrasound study at 31 weeks showed dicephalus after a previous study was interpreted as representing a normal twin gestation.2 Survival of dicephalus twins is very short and ranges from a stillbirth to a few hours. Our case of dicephalus is unique because of the duration of survival (11 days). In addition, the twins were able to undergo a complete diagnostic evaluation, which showed sharing of multiple vital structures including the heart and liver. Surgical separation of dicephalic twins is impossible, and only comfort measures are appropriate.
REFERENCE? 1. Hoyle RM: Surgical separation of conjoined twins. Surg Gynecol Obstet 170:549-562,199O 2. Hammond DI, Okun NB, Carpenter BF, et al: Prenatal ultrasonographic diagnosis of dicephalus conjoined twins. Can
Assoc Radio1 J 42:357-359,199l 3. Itoh K, Yulihiro I, Chiho 0, et al: Pathological findings in dicephalus dipus dibrachius: implications for mechanisms in two pairs of lateral conjoined twins. Kobe J Med Sci 39:95-106, 1993
Dipus
Dibrachius:
By Jonathan
I. Groner,
An Unusual
Douglas W. Teske, and Steven Columbus, Ohio
l Conjoined twinning is a rare anomaly, occurring in one of every 50,000 births. Dicephalus dipus dibrachius is an extremely rare form of conjoined twinning in which the infant has two arms, two legs, one trunk, but two heads. These infants are often stillborn or die shortly after birth. The authors describe a case of dicephalus twinning with ll-day survival. A thorough investigation using multiple imaging modalities (plain radiographs, contrast studies, ultrasonography, and magnetic resonance imaging) demonstrated that these twins had separate spinal columns but shared multiple internal organs including heart, liver, pancreas, intestine and bladder. Based on the anatomy of this case, the authors conclude that separation of dicephalus dipus dibrachius twins should not be attempted. Copyright o 1996by W.B. Saunders Company
INDEX chius.
WORDS:
Conjoined
twins,
dicephalus
dipus
Case of Conjoined
dibra-
HE INCIDENCE of conjoined twinning is most often stated as 1 in 50,000 births. Because the majority of conjoined infants are stillborn, the true incidence of liveborn conjoined twins is approximately one in 200,OOO.r Thoracopagus accounts for 40% of conjoined twinning, omphalopagus, 33%; pyopagus (joined at the sacrum), 19%; ischiopagus, 6%; and craniopagus, 2%. Dicephalus dipus dibrachius is a rare form of twinning in which the children have two heads but only two arms, two legs, and one torso. This anomaly is so unusual, and survival is so limited, that it is not included in many review articles. We report a case of dicephalus dipus dibrachius twins that survived 11 days and underwent an extensive clinical evaluation.
T
CASE REPORT
Twins
Teich
On physical examination, the twins were pink and active, but the left twin appeared to be making a stronger respiratory effort. Their heads were normocephalic except for indentations where they were in contact. Both heads had soft fontanelles, normal appearing eyes, patent ear canals and nares, and intact palates. The heart rate was 138 beats per minute with a regular rhythm and a holosystolic hum and a split Sl. Breath sounds were clear but the right infant was occasionally apneic. Mild intercostal retractions were observed. The abdomen was soft and not distended with a single umbilical cord containing two arteries and one vein. Examination of the external genitalia showed a single vagina that split posteriorly. A skin dimple was noted on the left side of the perineum without a patent anus. On the right side, there was a patent anus with meconium present. Two spines were palpable, but only one pelvis. Each extremity had five digits and appeared normal, except for wide spacing between the first and second toes of both feet. On neurological examination, all extremities moved spontaneously. Painful stimuli to the left arm or leg caused the left face to grimace, stimulation of the right arm or leg caused the right twin to respond.
Radiographic Studies Plain radiographs showed two thoracic cavities and two separate vertebral columns ending in paired sacral structures that were attached to a single, widely flared pelvis (Fig 2). Above the diaphragm, a spherical density between the two spines appeared to be a shared heart. With abdominal ultrasonography, one liver was seen in the middle of the upper abdominal cavity, one gallbladder, one pancreas, two kidneys (with a possible partial duplication of the left kidney), and a single bladder were seen. There was no evidence of obstructive uropathy. A magnetic resonance imaging (MRI) scan was performed but, because of motion artifact from the infants’ tachypnea, it added little new information. Under fluoroscopy, barium was instilled into the stomach of the left twin via a feeding tube. The contrast material passed into the duodenum and jejunum, then refluxed into the right twin’s duodenum and stomach, demonstrating a duplication of the upper intestinal tract. The barium then filled the remainder of the small bowel and emptied into a normally rotated and normal appearing colon and rectum (Fig 3).
The twins weighed 4.4 kg at birth, which followed an uncomplicated 38-week pregnancy in a 21-year-old gravida 1 woman who had obtained prenatal care. Three ultrasound examinations did not disclose any abnormalities. A cesarean section was performed electively because of breech presentation. Apgar scores were 1 and 9. The twins were noted to have two arms, two legs, one torso, but two heads and two necks (Fig 1). Each infant received 100% oxygen by face mask for a short time. A peripheral intravenous line was started; they were placed in 50% oxygen by face mask, and transported to Columbus Children’s Hospital.
From the Departments of tal, Columbus, OH. Address reprint requests to St, Suite 6C, Columbus, OH Copyright 0 1996 by W. B. 0022-3468/96/3112-0025$03.00/O 1698
Surgery Jonathan 43205. Saunders
and Pediatrics, I. Gronev,
Children’s MD,
Hospi-
555 South
18th
Company Fig 1.
JournalofPediatric
Dicephalus
Surgery,
dipus
Vol31,
dibrachius
conjoined
No 12 (December),
twins.
1996: pp 1698-1700
DICEPHALUS
DIPUS
1699
DIBRACHIUS
Echocardiographic Studies Real-time, two-dimensional echocardiography revealed a single heart with complex anatomy. An inferior vena cava was associated with each twin’s spine. These emptied into a common systemic venous atrium in the midline. There were bilateral atria1 septae, and each side had a fossa ovalis. The left twin had two atrroventricular valves. a pulmonary venous atrium; and two ventricles with normally related great arteries. The right twin had a pulmonary venous atrium and a single atrioventricular valve leading to a single ventricular chamber that functioned as a double outlet right ventricle (Fig 4). The right aorta was smaller caliber than the left one and persistent arterial duct shunting was present bilaterally.
Hospital Course The infants were given oxygen by nasal cannula (.5 Limin). and gavage feedings were split between the two infants, which they tolerated well. The twins were felt to be inseparable from a surgical standpoint and, because of their poor prognosis, a “do not resuscitate” order was written. On day 11, the babies were electively weaned off oxygen in preparation for possible discharge. Later that day, they became lethargic and a cardiac gallop was noted intermittently. A few hours later they developed apnea and bradycardia and died. Permission for autopsy was denied. The suspected cause of death was congestive heart failure. Fig 2. Radiogram columns and a single
of conjoined pelvis.
twins
demonstrating
paired
spinal
Ant t
Fig 3. Gastrointestinal contrast Barium instilled in the left stomach
radiography of conjoined twins. refluxes into the right stomach.
Fig 4. (A) Echocardiogram, and (B) schematic of cardiac anatomy of the conjoined twins. A, left twin’s pulmonary atrium; LTLV. left twin’s left Ventricle; LTRV, left twin’s right ventricle; MV, left twin’s mitral valve; RTRV, right twin’s double outlet right ventricle.
1700
GRONER,
DISCUSSION
Conjoined twinning occurs in 1 of every 50,000 to 60,000 births, but 60% of affected infants do not survive. Dicephalus dipus dibrachius is one of the least frequent variants of conjoined twinning.l The cause of dicephalus twinning is unknown, and there are no known risk factors that are specific to this anomaly. One case of dicephalus twinning was associated with maternal exposure to radiation from the 1986 nuclear reactor accident in Chernobyl.2 The diagnosis of dicephalus twinning has been made on prenatal ultrasound exam.3 In one case, an
TESKE,
AND
TEICH
ultrasound study at 31 weeks showed dicephalus after a previous study was interpreted as representing a normal twin gestation.2 Survival of dicephalus twins is very short and ranges from a stillbirth to a few hours. Our case of dicephalus is unique because of the duration of survival (11 days). In addition, the twins were able to undergo a complete diagnostic evaluation, which showed sharing of multiple vital structures including the heart and liver. Surgical separation of dicephalic twins is impossible, and only comfort measures are appropriate.
REFERENCE? 1. Hoyle RM: Surgical separation of conjoined twins. Surg Gynecol Obstet 170:549-562,199O 2. Hammond DI, Okun NB, Carpenter BF, et al: Prenatal ultrasonographic diagnosis of dicephalus conjoined twins. Can
Assoc Radio1 J 42:357-359,199l 3. Itoh K, Yulihiro I, Chiho 0, et al: Pathological findings in dicephalus dipus dibrachius: implications for mechanisms in two pairs of lateral conjoined twins. Kobe J Med Sci 39:95-106, 1993