Emergency
Separation
of Conjoined
By J.M. Walton, D.A. Gillis, J.M. Giacomantonio, Halifax,
Nova
0 Female omphalopagus conjoined twins were successfully delivered vaginally and required emergency surgical separation shortly after birth for gastroschisis. Shared tissue included conjoined bowel; one twin also had a complex cloaca1 abnormality and patent urachus. A 2-year follow-up is presented. A review of the relevant literature confirms that this is the first example of gastroschisis conjoining omphalopagus twins. Copyright o 1991 by W.B. Saunders Company INDEX WORDS: Conjoined twins, omphalopagus; sis.
C humans,
ONJOINED
fInm II”,,,
gastroschi-
twinning is a rare occurrence in with a reported incidence ranging
. II-r,““” A nnnl tn I1 :1; I” II in 111inn I”“,““”nnn
ntPnn--;Pc
ylti~IwIIL4”~.
2 ~~~~
result in conjoined twinning occur between the 13th and 15th day after fertilization, resulting in partial division of the zygote.3 The partially fused zygotes are monoamniotic and monochorionic and represent an aberration of the twinning process.’ Earlier reports indicated that 60% were stillborn; antenatal diagnosis and increased use of cesarean sections are credited with reducing the incidence to 40%.2.5.6For unknown reasons, 70% of conjoined twins are female.’ In half of all cases there is hyd.ramnios; however, the incidence in omphalopagus twins is only ll%, close to the expected rate for twin pregnancies (10%).h events
that
CASE REPORT Omphalopagus twin girls were born to a gravida 2, para 1 mother. Apart from the presence of twins, the pregnancy was unremarkable. Prenatal ultrasound examinations showed that the twins moved freely from each other. The last ultrasound at 34 weeks showed a “cystic structure” between the twins that was interpreted as possibly an omphalocele (Fig 1). Onset of labor was spontaneous at 34.5 weeks. Artificial rupture of the membranes showed meconium staining, but labor was otherwise uncomplicated, lasting 5 hours. The twins were delivered together in an interlocked position with twin A vertex and twin % being breech. Apgars were 8 and 8 for twin A and 9 and 18 for twin % (Fig 2). There were two separate umbilical cords with three vessels each, situated in each twin to the left of the gastroschisis. The umbilical cords joined just before reaching a single placenta that weighed 680 g. Total birthweight was 3,980 g. Both twins had typical gastroschisis and were conjoined by the exposed bowel. Twin A had one perineal orifice, splaying of the symphysis pubis, and small labia. Her lower anterior abdominal wall was very thin with a relatively iow umbiiicus and a patent urachai structure connected to ihe bladder. Meconium was noted to pass from the single perineal orifice. Twin % had imperforate anus but no other obvious anomalies. Her labia, vaginal orifice, and urethral meatus looked normal. Because of the exposed bowel, the twins were prepared for emergency surgery. Anesthesia was induced simultaneously with Journal
of Pediatric
Surgery,
Vol26,
No 11 (November),
1991:
pp 1X37-1340
Twins
A.H. Hayashi, and H.Y.C. Lau
Scotia
both twins being intubated. Intraoperative examination showed twin A had an apparently normal small bowel that entered a common large cecum. From this, a short segment of colon passed down into the pelvis behind the vagina. Twin % had no colon. Her small bowel ended blindly, connected to the cecum by a fibrous band that was interpreted as an area of ileal atresia. A small “bud” arose from the single cecum. This may have represented the underdeveloped colon of twin B. The uterus of each infant appeared to be didelphic. The ovaries and fallopian tubes looked normal in each twin. The cecum by which the two twins were connected had two appendices (Fig 3). Separation was begun by excising the single cecum. In twin A an ileostomy was established and the proximal end of her short colon was exteriorized separately as a mucous fistula. The urachal anomaly was excised and the connection with the bladder was oversewn. In twin B, an end-ileostomy was established. Abdominal ~__LL_I~~ ___J~ _~~~.___~_ wau11-1_ closure in eacn oaoy was “one piimariiy without tensron. m-_. r ora,I operative time was slightly over 3 hours. Postoperatively, the infants were maintained initially on parenteral nutrition with a gradual progression to oral feedings. Twin B had transient bouts of ileostomy dysfunction with partial obstruction. which was managed nonoperatively. Both infants were discharged at 2 months of age, twin A weighing 3.06 kg and twin % weighing 3.56 kg. Twin B subsequently required readmission for ileostomy revision and repair of a small incisional hernia. Recent imaging studies of twin A showed the bladder to be bilobed, large, and hypotonic (Fig 4). Injection of contrast material into the mucous fistula demonstrated that the rectum entered into the left half of an apparently septated vagina (Fig 5). Her perineal floor appears to be poorly developed and because of the cloaca1 anomaly her ability to empty the bladder completely has not been documented. There has been no evidence of significant reflux in either infant and they have been free from urinary tract infections. Neither infant has an identifiable spinal anomaly and both walk normally (Fig 2). They have thrived and their general health at the present time is excellent. DISCUSSION
Conjoined twins have always attracted a great deal of public attention. The most famous were Eng and f-Y__-- n.._,_.._ Ll__ --l-:--l “0:-___-_ L__.:__ Ulallg DUIlKt?l, lilt: Ull~lIlkll 31amtxG LWIIlS” wiio were on dispIay with P.T. Barnum in 19th century America. Ambrose Pare, the famous 16th century French surgeon, described 11 causes for these “monsters” in his classic “Of Monsters And Prodigies.“7
From the Department of Surgey, ZWK Children’s Hospital, Halifax, Nova Scotia. Presented at the 22nd Annual Meeting of the Canadian Association 0jPaediairic Surgeons, Sf John ‘s, iv’ewfoundiand, August 22-25, i99. Address reprint requests to D.A. Gillis, MD, Department of Surgery, ZWK Children’s Hospital, 5850 UniversityAve, Halifax, Nova Scotia 835 3G9, Canada. Copyright o 1991 by W.B. Saunders Company 0022.3468/9112611-0022$03.0010 1337
1338
WALTON ET AL
Fig 2. “Babygram” with twin A on left and twin Bon the right. The twins were widely separated and connected by exposed bowel. Vertebra appeared to be normal. Fig 1. Ultrasound at 34 weeks’ gestation shows an anteriorly placed placenta with a cystic structure (narrow white arrow) and a three-vessel umbilical cord (wide white arrow) on the fetal abdomen.
Omphalopagus twins are described as being joined at the abdomen from the xiphoid process to the umbilicus. Conjoined structures may include liver, biliary tree, upper or lower gastrointestinal tract, and bladder.
In 1689, Konig described the first successful separation of conjoined twins. These were omphalopagus, being connected only by skin.* Sixty-two sets of omphalopagus conjoined twins have been reported in the English language literature. Twenty-six sets were joined at the xiphoid process and abdomen but had separate thoracic cavities. Twenty-seven sets had fusion of the midabdominal structures with no junc-
Fig 3. Omphalopagus twins with gastroschisis conjoined by a large cecum. Dotted lines indicate points of surgical separation.
EMERGENCY SEPARATION OF CONJOINED
1339
TWINS
Table 1. Reasons for Emergency Neonatal Separation Bowel obstruction Poor condition of one or both twins Removal of stillborn twin Trauma to conjoined tissue Thin omphalocele membrane Total
Fig 4.
Anteroposterior
view of twin A’s pelvis during “cloacogram”
at 2 years of age. Injection of contrast material shows a bilobed hypotonic bladder (curved arrows) and the right half of a septated vagina (small arrows). Dye introduced via the proximal end of the mucous fistula (large arrow) is seen to enter the left half of the septated vagina (open arrow).
tion of the xiphoid cartilage. There was a preponderance of females. Sixteen twins in 10 sets were stillborn 1.3.9-16 Omphaloceles occur in one third of omphalopagus twins. Only four occurred when the xiphoid cartilages
were joined,9,‘7-‘9and none of these were ruptured. Omphaloceles were reported to be ruptured in @~‘o~“.” of 1511-14.22-28 cases when the xiphoid cartilages were not fused. Fusion of the xiphoid cartilage in conjoined twins conceivably may protect an omphalocele from undue shearing pressure, which may result in rupture. We found no reported cases of gastroschisis in omphalopagus twins. Imperforate anus occurred in six cases, all without xiphoid cartilage union, three of which were described as having ruptured omphaloceles.3~‘“~‘0.“‘23~‘9 In four of these six sets a patent urachus was described in one or both twins.3.10.“‘,“9 Seventeen of the 62 sets of omphalopagus twins required emergency separation in the neonatal pe(Table 1). Twelve infants died in riod 1~3~14~1’~21~26~?7~29~3S the perioperative period after emergency neonatal ~epa~ation.1~14~19~21~31~34
In addition, 16 other sets of omphalopagus twins have been documented in epidemiological studHowever, anatomic details of conjoined tisies. 2,36.37 sues are not present in these reports and so have been excluded from the analysis. None of the total of 62 reported sets of omphalopagus twins were conjoined by a gastroschisis. However, Edmonds and Layde’s epidemiologic review included three thoracopagus twins with gastroschisis.’ In two of these gastroschisis was related to the site of conjoining, whereas in the third the abnormality was separate from the conjoined tissue. In their review, none of the omphalopagus (or xiphopagus) conjoined twins had gastroschisis. This appears to be the only documented case of omphalopagus twins conjoined by gastroschisis. Restoration of normal fecal continence in these twins in the future will be difficult. Twin B has no colon and twin A may have significant neurological impairment to pelvic viscera. So far, both twins are developmentally within normal limits and we feel that their long-range outlook is excellent.
ACKNOWLEDGMENT Fig 5. Illustration showing sag&al anatomy at birth. The large intestine septated vagina.
section of twin A’s pelvic enters the left half of the
Special thanks to Judy Charman and Valerie Young for preparation of this manuscript.
1340
WALTON
ET AL
REFERENCES 1. Bland KG, Hammer B: Xiphopagus twins. Cent Afr J Med 8:371-375, 1962 2. Edmonds LD, Layde PM: Conjoined twins in the United States, 1970-77. Teratology 25:301-308,1982 3. Votteler TP: Surgical separation of conjoined twins. AORN J 3535-46, 1982 4. Zimmerman AA: Embryologic and anatomic considerations of conjoined twins. Birth Defects Orig Art Ser 3:18-27,1967 5. Votteler TP: Conjoined twins, in Welch KJ, Randolph JG, Ravitch MM, et al (eds): Pediatric Surgery, ~012. Chicago, IL, Year Book, 1986, pp 771-779 6. Harper RG, Kenigsberg K, Conception GS, et al: Xiphopagus conjoined twins: A 300 year review of the obstetric, morphopathologic, neonatal and surgical parameters. Am J Obstet Gynecol 137:617-629, 1980 7. Pare A: Complete Works. Forst French Ed, Translated into English by Thomas Johnson, 1678 8. Konig G: Sibi Invicem adnati Feliciter separati, Ephemerid Natur Curios Dec. II, Ann VIII, Obs. 145,1689 9. Rawlings EE, Warwick R: A case of conjoined twins. Br J Obstet Gynaeco158:452-455, 1951 10. Rajadurai VS, Matthai J, Jadhav MA: Omphalopagus twins and twin transfusion syndrome. Indian J Pediatr 55811.816,1988 11. Baudouin M: The double xiphopagus monster living at the beginning of labor. Rev Med Fr 17:465-471,1936 12. Roddie TW: A case of conjoined twins. Br Med J 1:11631164,1957 13. Michaels JP: The conjoined twins of Orlando. Birth Defects Orig Art Ser 3:145-147,1967 14. Janet M, Vojtko M, Kubikovia E: Xipho-omphalopagus Siamese twins with multiple abnormalities of the gastro-intestinal tract. Rozhl Chir 68:616-619, 1989 15. Mabogunje OA, Laurie JH: Conjoined twins in West Africa. Arch Dis Child 55:626-630, 1980 16. Joshi L: Conjoined twins. J Indian Med Assoc 63:222-223, 1974 17. DeAngelis RR, Dursi JF, Ibach JR: Successful separation of xiphopagus conjoined twins. Ann Surg 172:302-305,197O 18. Lobe TE, Oldham KT, Richardson Cl: Successful separation of conjoined biliary tract in a set of omphalopagus twins. J Pediatr Surg 24:930-931,1989 19. Wong TJ, Lyou YT, Chec CP, et al: Management of xiphopagus conjoined twins with small bowel obstruction. J Pediatr Surg 21:53-57,1986 20. Cywes S, Block CE: Conjoined twins. A review with report of a case. S Afr Med J 38817.821,1964
21. Gans SL, Morgenstern L, Gettelman E, et al: Separation of conjoined twins in the newborn period. J Pediatr Surg 3:565-574, 1968 22. Melin JR: Intrapartum diagnosis of conjoined twins. Obstet Gynecol29:.50-53, 1967 23. Joseph GS, Prusty S: Conjoined twins (Siamese twins). J Indian Med Assoc 53:25-26,1969 24. Kitamura E, Kitamura Y, Toyoda Y, et al: Anaesthetic management for surgical separation of xiphoomphalophagus twins. Jpn J Anesthesiol25:589-599, 1976 25. O’Neil JA Jr, Holcomb GW III, Schnaufer L, et al: Surgical experience with thirteen conjoined twins. Ann Surg 208:299-312, 1988 26. Paramsothy M, Wong TJ, Woon ST, et al: Technetium-99mdiethyl-IDA sequential hepatobiliary scintigraphy in the preoperative evaluation of omphalopagus conjoined twins. Aust Radio1 28358-361, 1984 27. Prasad CN, Haran RH, Prasad GR, et al: Omphalopagus successful separation of conjoined twins in the newborn period. Indian Pediatr 26:953-957, 1989 28. Herbert WNP, Cefalo RC, Koontz WL: Perinatal management of conjoined twins. Am J Perinatol 1:58-63, 1983 29. Riker W, Traisman H: Conjoined twins; report of three cases. Ill Med J 126:450-454,1964 30. Turner RJ, Hankins GDV, Weinreb JC, et al: Magnetic resonance imaging and ultrasonography in the antenatal evaluation of conjoined twins. Am J Obstet Gynecol155:645-649,1986 31. Saing H, Tam PKH, Lau JTK, et al: Advanced necrotizing enterocolitis: An indication for emergency separation of omphalopagus conjoined twins. Aust Pediatr J 23:129-130, 1987 32. Ure BM, Holschneider Am, Gharib M, et al: Emergency separation of a neonatal xypho-omphalopagus twin. Z Kinderchir 44:176-180,1989 33. Carrai PE, Pampaloni A: Separazione chirugica ad esito felice di due gemelli xifopaghi. Riv Clin Pediatr 81:374-387, 1968 34. Oberniedemayr A, Rictel K, Westhues G: Siamese twins from Munich. Cah Co11Med Hop Paris 10:749-756,1969 35. Reitman H, Smith EE, Geller JS: Separation and survival of xiphopagus twins. JAMA 153:1360-1362,1953 36. Milham S: Symmetrical conjoined twins: An analysis of the birth records of twenty-two sets. J Pediatr 69:643-647,1966 37. Castilla EE, Lopez-Camelo JS, Orioli IM, et al: The epidemiology of conjoined twins in Latin America. Acta Genet Med Gemellol37:111-118,1988
Separation
of Conjoined
By J.M. Walton, D.A. Gillis, J.M. Giacomantonio, Halifax,
Nova
0 Female omphalopagus conjoined twins were successfully delivered vaginally and required emergency surgical separation shortly after birth for gastroschisis. Shared tissue included conjoined bowel; one twin also had a complex cloaca1 abnormality and patent urachus. A 2-year follow-up is presented. A review of the relevant literature confirms that this is the first example of gastroschisis conjoining omphalopagus twins. Copyright o 1991 by W.B. Saunders Company INDEX WORDS: Conjoined twins, omphalopagus; sis.
C humans,
ONJOINED
fInm II”,,,
gastroschi-
twinning is a rare occurrence in with a reported incidence ranging
. II-r,““” A nnnl tn I1 :1; I” II in 111inn I”“,““”nnn
ntPnn--;Pc
ylti~IwIIL4”~.
2 ~~~~
result in conjoined twinning occur between the 13th and 15th day after fertilization, resulting in partial division of the zygote.3 The partially fused zygotes are monoamniotic and monochorionic and represent an aberration of the twinning process.’ Earlier reports indicated that 60% were stillborn; antenatal diagnosis and increased use of cesarean sections are credited with reducing the incidence to 40%.2.5.6For unknown reasons, 70% of conjoined twins are female.’ In half of all cases there is hyd.ramnios; however, the incidence in omphalopagus twins is only ll%, close to the expected rate for twin pregnancies (10%).h events
that
CASE REPORT Omphalopagus twin girls were born to a gravida 2, para 1 mother. Apart from the presence of twins, the pregnancy was unremarkable. Prenatal ultrasound examinations showed that the twins moved freely from each other. The last ultrasound at 34 weeks showed a “cystic structure” between the twins that was interpreted as possibly an omphalocele (Fig 1). Onset of labor was spontaneous at 34.5 weeks. Artificial rupture of the membranes showed meconium staining, but labor was otherwise uncomplicated, lasting 5 hours. The twins were delivered together in an interlocked position with twin A vertex and twin % being breech. Apgars were 8 and 8 for twin A and 9 and 18 for twin % (Fig 2). There were two separate umbilical cords with three vessels each, situated in each twin to the left of the gastroschisis. The umbilical cords joined just before reaching a single placenta that weighed 680 g. Total birthweight was 3,980 g. Both twins had typical gastroschisis and were conjoined by the exposed bowel. Twin A had one perineal orifice, splaying of the symphysis pubis, and small labia. Her lower anterior abdominal wall was very thin with a relatively iow umbiiicus and a patent urachai structure connected to ihe bladder. Meconium was noted to pass from the single perineal orifice. Twin % had imperforate anus but no other obvious anomalies. Her labia, vaginal orifice, and urethral meatus looked normal. Because of the exposed bowel, the twins were prepared for emergency surgery. Anesthesia was induced simultaneously with Journal
of Pediatric
Surgery,
Vol26,
No 11 (November),
1991:
pp 1X37-1340
Twins
A.H. Hayashi, and H.Y.C. Lau
Scotia
both twins being intubated. Intraoperative examination showed twin A had an apparently normal small bowel that entered a common large cecum. From this, a short segment of colon passed down into the pelvis behind the vagina. Twin % had no colon. Her small bowel ended blindly, connected to the cecum by a fibrous band that was interpreted as an area of ileal atresia. A small “bud” arose from the single cecum. This may have represented the underdeveloped colon of twin B. The uterus of each infant appeared to be didelphic. The ovaries and fallopian tubes looked normal in each twin. The cecum by which the two twins were connected had two appendices (Fig 3). Separation was begun by excising the single cecum. In twin A an ileostomy was established and the proximal end of her short colon was exteriorized separately as a mucous fistula. The urachal anomaly was excised and the connection with the bladder was oversewn. In twin B, an end-ileostomy was established. Abdominal ~__LL_I~~ ___J~ _~~~.___~_ wau11-1_ closure in eacn oaoy was “one piimariiy without tensron. m-_. r ora,I operative time was slightly over 3 hours. Postoperatively, the infants were maintained initially on parenteral nutrition with a gradual progression to oral feedings. Twin B had transient bouts of ileostomy dysfunction with partial obstruction. which was managed nonoperatively. Both infants were discharged at 2 months of age, twin A weighing 3.06 kg and twin % weighing 3.56 kg. Twin B subsequently required readmission for ileostomy revision and repair of a small incisional hernia. Recent imaging studies of twin A showed the bladder to be bilobed, large, and hypotonic (Fig 4). Injection of contrast material into the mucous fistula demonstrated that the rectum entered into the left half of an apparently septated vagina (Fig 5). Her perineal floor appears to be poorly developed and because of the cloaca1 anomaly her ability to empty the bladder completely has not been documented. There has been no evidence of significant reflux in either infant and they have been free from urinary tract infections. Neither infant has an identifiable spinal anomaly and both walk normally (Fig 2). They have thrived and their general health at the present time is excellent. DISCUSSION
Conjoined twins have always attracted a great deal of public attention. The most famous were Eng and f-Y__-- n.._,_.._ Ll__ --l-:--l “0:-___-_ L__.:__ Ulallg DUIlKt?l, lilt: Ull~lIlkll 31amtxG LWIIlS” wiio were on dispIay with P.T. Barnum in 19th century America. Ambrose Pare, the famous 16th century French surgeon, described 11 causes for these “monsters” in his classic “Of Monsters And Prodigies.“7
From the Department of Surgey, ZWK Children’s Hospital, Halifax, Nova Scotia. Presented at the 22nd Annual Meeting of the Canadian Association 0jPaediairic Surgeons, Sf John ‘s, iv’ewfoundiand, August 22-25, i99. Address reprint requests to D.A. Gillis, MD, Department of Surgery, ZWK Children’s Hospital, 5850 UniversityAve, Halifax, Nova Scotia 835 3G9, Canada. Copyright o 1991 by W.B. Saunders Company 0022.3468/9112611-0022$03.0010 1337
1338
WALTON ET AL
Fig 2. “Babygram” with twin A on left and twin Bon the right. The twins were widely separated and connected by exposed bowel. Vertebra appeared to be normal. Fig 1. Ultrasound at 34 weeks’ gestation shows an anteriorly placed placenta with a cystic structure (narrow white arrow) and a three-vessel umbilical cord (wide white arrow) on the fetal abdomen.
Omphalopagus twins are described as being joined at the abdomen from the xiphoid process to the umbilicus. Conjoined structures may include liver, biliary tree, upper or lower gastrointestinal tract, and bladder.
In 1689, Konig described the first successful separation of conjoined twins. These were omphalopagus, being connected only by skin.* Sixty-two sets of omphalopagus conjoined twins have been reported in the English language literature. Twenty-six sets were joined at the xiphoid process and abdomen but had separate thoracic cavities. Twenty-seven sets had fusion of the midabdominal structures with no junc-
Fig 3. Omphalopagus twins with gastroschisis conjoined by a large cecum. Dotted lines indicate points of surgical separation.
EMERGENCY SEPARATION OF CONJOINED
1339
TWINS
Table 1. Reasons for Emergency Neonatal Separation Bowel obstruction Poor condition of one or both twins Removal of stillborn twin Trauma to conjoined tissue Thin omphalocele membrane Total
Fig 4.
Anteroposterior
view of twin A’s pelvis during “cloacogram”
at 2 years of age. Injection of contrast material shows a bilobed hypotonic bladder (curved arrows) and the right half of a septated vagina (small arrows). Dye introduced via the proximal end of the mucous fistula (large arrow) is seen to enter the left half of the septated vagina (open arrow).
tion of the xiphoid cartilage. There was a preponderance of females. Sixteen twins in 10 sets were stillborn 1.3.9-16 Omphaloceles occur in one third of omphalopagus twins. Only four occurred when the xiphoid cartilages
were joined,9,‘7-‘9and none of these were ruptured. Omphaloceles were reported to be ruptured in @~‘o~“.” of 1511-14.22-28 cases when the xiphoid cartilages were not fused. Fusion of the xiphoid cartilage in conjoined twins conceivably may protect an omphalocele from undue shearing pressure, which may result in rupture. We found no reported cases of gastroschisis in omphalopagus twins. Imperforate anus occurred in six cases, all without xiphoid cartilage union, three of which were described as having ruptured omphaloceles.3~‘“~‘0.“‘23~‘9 In four of these six sets a patent urachus was described in one or both twins.3.10.“‘,“9 Seventeen of the 62 sets of omphalopagus twins required emergency separation in the neonatal pe(Table 1). Twelve infants died in riod 1~3~14~1’~21~26~?7~29~3S the perioperative period after emergency neonatal ~epa~ation.1~14~19~21~31~34
In addition, 16 other sets of omphalopagus twins have been documented in epidemiological studHowever, anatomic details of conjoined tisies. 2,36.37 sues are not present in these reports and so have been excluded from the analysis. None of the total of 62 reported sets of omphalopagus twins were conjoined by a gastroschisis. However, Edmonds and Layde’s epidemiologic review included three thoracopagus twins with gastroschisis.’ In two of these gastroschisis was related to the site of conjoining, whereas in the third the abnormality was separate from the conjoined tissue. In their review, none of the omphalopagus (or xiphopagus) conjoined twins had gastroschisis. This appears to be the only documented case of omphalopagus twins conjoined by gastroschisis. Restoration of normal fecal continence in these twins in the future will be difficult. Twin B has no colon and twin A may have significant neurological impairment to pelvic viscera. So far, both twins are developmentally within normal limits and we feel that their long-range outlook is excellent.
ACKNOWLEDGMENT Fig 5. Illustration showing sag&al anatomy at birth. The large intestine septated vagina.
section of twin A’s pelvic enters the left half of the
Special thanks to Judy Charman and Valerie Young for preparation of this manuscript.
1340
WALTON
ET AL
REFERENCES 1. Bland KG, Hammer B: Xiphopagus twins. Cent Afr J Med 8:371-375, 1962 2. Edmonds LD, Layde PM: Conjoined twins in the United States, 1970-77. Teratology 25:301-308,1982 3. Votteler TP: Surgical separation of conjoined twins. AORN J 3535-46, 1982 4. Zimmerman AA: Embryologic and anatomic considerations of conjoined twins. Birth Defects Orig Art Ser 3:18-27,1967 5. Votteler TP: Conjoined twins, in Welch KJ, Randolph JG, Ravitch MM, et al (eds): Pediatric Surgery, ~012. Chicago, IL, Year Book, 1986, pp 771-779 6. Harper RG, Kenigsberg K, Conception GS, et al: Xiphopagus conjoined twins: A 300 year review of the obstetric, morphopathologic, neonatal and surgical parameters. Am J Obstet Gynecol 137:617-629, 1980 7. Pare A: Complete Works. Forst French Ed, Translated into English by Thomas Johnson, 1678 8. Konig G: Sibi Invicem adnati Feliciter separati, Ephemerid Natur Curios Dec. II, Ann VIII, Obs. 145,1689 9. Rawlings EE, Warwick R: A case of conjoined twins. Br J Obstet Gynaeco158:452-455, 1951 10. Rajadurai VS, Matthai J, Jadhav MA: Omphalopagus twins and twin transfusion syndrome. Indian J Pediatr 55811.816,1988 11. Baudouin M: The double xiphopagus monster living at the beginning of labor. Rev Med Fr 17:465-471,1936 12. Roddie TW: A case of conjoined twins. Br Med J 1:11631164,1957 13. Michaels JP: The conjoined twins of Orlando. Birth Defects Orig Art Ser 3:145-147,1967 14. Janet M, Vojtko M, Kubikovia E: Xipho-omphalopagus Siamese twins with multiple abnormalities of the gastro-intestinal tract. Rozhl Chir 68:616-619, 1989 15. Mabogunje OA, Laurie JH: Conjoined twins in West Africa. Arch Dis Child 55:626-630, 1980 16. Joshi L: Conjoined twins. J Indian Med Assoc 63:222-223, 1974 17. DeAngelis RR, Dursi JF, Ibach JR: Successful separation of xiphopagus conjoined twins. Ann Surg 172:302-305,197O 18. Lobe TE, Oldham KT, Richardson Cl: Successful separation of conjoined biliary tract in a set of omphalopagus twins. J Pediatr Surg 24:930-931,1989 19. Wong TJ, Lyou YT, Chec CP, et al: Management of xiphopagus conjoined twins with small bowel obstruction. J Pediatr Surg 21:53-57,1986 20. Cywes S, Block CE: Conjoined twins. A review with report of a case. S Afr Med J 38817.821,1964
21. Gans SL, Morgenstern L, Gettelman E, et al: Separation of conjoined twins in the newborn period. J Pediatr Surg 3:565-574, 1968 22. Melin JR: Intrapartum diagnosis of conjoined twins. Obstet Gynecol29:.50-53, 1967 23. Joseph GS, Prusty S: Conjoined twins (Siamese twins). J Indian Med Assoc 53:25-26,1969 24. Kitamura E, Kitamura Y, Toyoda Y, et al: Anaesthetic management for surgical separation of xiphoomphalophagus twins. Jpn J Anesthesiol25:589-599, 1976 25. O’Neil JA Jr, Holcomb GW III, Schnaufer L, et al: Surgical experience with thirteen conjoined twins. Ann Surg 208:299-312, 1988 26. Paramsothy M, Wong TJ, Woon ST, et al: Technetium-99mdiethyl-IDA sequential hepatobiliary scintigraphy in the preoperative evaluation of omphalopagus conjoined twins. Aust Radio1 28358-361, 1984 27. Prasad CN, Haran RH, Prasad GR, et al: Omphalopagus successful separation of conjoined twins in the newborn period. Indian Pediatr 26:953-957, 1989 28. Herbert WNP, Cefalo RC, Koontz WL: Perinatal management of conjoined twins. Am J Perinatol 1:58-63, 1983 29. Riker W, Traisman H: Conjoined twins; report of three cases. Ill Med J 126:450-454,1964 30. Turner RJ, Hankins GDV, Weinreb JC, et al: Magnetic resonance imaging and ultrasonography in the antenatal evaluation of conjoined twins. Am J Obstet Gynecol155:645-649,1986 31. Saing H, Tam PKH, Lau JTK, et al: Advanced necrotizing enterocolitis: An indication for emergency separation of omphalopagus conjoined twins. Aust Pediatr J 23:129-130, 1987 32. Ure BM, Holschneider Am, Gharib M, et al: Emergency separation of a neonatal xypho-omphalopagus twin. Z Kinderchir 44:176-180,1989 33. Carrai PE, Pampaloni A: Separazione chirugica ad esito felice di due gemelli xifopaghi. Riv Clin Pediatr 81:374-387, 1968 34. Oberniedemayr A, Rictel K, Westhues G: Siamese twins from Munich. Cah Co11Med Hop Paris 10:749-756,1969 35. Reitman H, Smith EE, Geller JS: Separation and survival of xiphopagus twins. JAMA 153:1360-1362,1953 36. Milham S: Symmetrical conjoined twins: An analysis of the birth records of twenty-two sets. J Pediatr 69:643-647,1966 37. Castilla EE, Lopez-Camelo JS, Orioli IM, et al: The epidemiology of conjoined twins in Latin America. Acta Genet Med Gemellol37:111-118,1988
