Cnjoined Twins

Abstract

Ahstruct.During the years 1960 to I970 inclusive, six conjoined twins were delivered out of a total of 403 441 deliveries including 3 276 twins and 37 triplet deliveries, an incidence of 1 in 67241 deliveries and 1 in 655 twin deliveries. A seventh cilnjained twin was delivered in late January 1971: inclusion of this case as well as the deliveries in January 1971 would lead to an incidence of I in 57 975 deliveries and I in 546 twin deliveries. Four of the twins were thoracopagus. one craniopagus, one dicephalus tripus tetrabrachius and one syncephalus. One of thc thoracopagus twins occurred in a triplet pregnancy. All except two were delivered alive; four died within a few hours to a few days. One t h x u p a g u s survived till 3 months of age; surgical separation was then attempted resulting on one survival whr, has developed normally and is now 7 years old. Antenatal diagnosis is necessary if the siirvival rate is to be improved.Conjoined twins have fascinated both physician and layman over the centuries and many excellent papers have been written about them. In 1952. Sebastian Munster (12) reported on a case of craniopagus alive a t the age of 6 years. About 400 to 500 cases of conjoined twins have been reported (3). Because of its extreme rarity. many papers have been in the form of case reports a n d / o r reviews of the subject. From available literature. only one series of conjoined twins has been reported from a single hospital ( I I); this is because the condition is so rare that a single case may not occur for many years. As a result, the incidences reported are a t best very approximate (8).I t is the purpose of this paper to present a n analysis of the cases which occurred in the Kandang Kerbau Hospital, Singapore during the last 11 years. MATERIALFrom 1960 to 1970, six cases of conjoined twins were encountered out of 403 441 deliveries giving an incidence of I in 67 241 deliveries. One of the twins was delivered before arrival at the hospital, but as the total deliveries in the hmpital include all such cases (born before arrival), this does not affect th-calculation of the incidence. This is compared with an incidence of 4 in 25 OOO (11).3 in X.5000 (10) and 2 in 100000 (18). More recently.Compton (2) reviewed five cases (from 2 h3spitals) OCcurring in a period of 20 years, during which t h m were about 250000 deliveries. an incidence of I in 50000. During this same period. 3 276 twins and 37 triplets were delivered: the incidence of conjoined twins c>mplicating twin gestations is therefore I in 655 and that for conjoined twins complicating triplet pregnancies is I in 37. Compton (1971) found an incidcncc of I conjoined twin in 900 twin deliveries but as the incidence of twin pregnancies for a single year was projected over 20 years to arrive at the total number of twins delivered during this period. the incidence must be considered to be only approximate. In the present paper. thc total number of twins delivered were actually taken frdm th-records. The incidence with regard to triplet pregnancies ...

The antepartum findings of conjoined twins

“…It is also estimated that conjoined twins will occur once in every 200 t o 400 pairs of monozygotic twins (7,(16)(17)(18). Thus the midrange estimate is that conjoined twins occur once in every 40,000 to 80,000 live births.…”

“…Although the entity of conjoined twins is a rare and unusual obstetrical occurrence, if the diagnosis can be substantiated prior to the onset of labor, the twins may be salvaged for subsequent repair (7,8,13,18,23) and the mother spared a dangerous attempt at vaginal delivery. Emergency embryotomy was the usual fate of unsuspected conjoined twins, but newer diagnostic and surgical techniques can now offer these twins the promise of a relatively normal life.…”

“…These female twins, born in 1100 A.D., lived for 34 years (11). Since that time, approximately 500 cases of conjoined twins have been described in the literature (7,11,(14)(15)(16). A complete history of conjoined twins is beyond the scope of this paper, but the reader is encouraged to read the references cited.…”

“…If one were to compile a list of the most common findings of conjoined twins (6-11, 16, 18, 20, (16,18), if polyhydramnios is not present, as in the case presented, if triplets are present (7), if the twins are not in a constant bibreech position (10,11,18), or if the union is a small bridge of soft tissue that allows change of relative fetal position (8,18). There may also be some confusion in cases of twins that are not conjoined, yet demonstrate a bibreech position with hyperextension of one of the cervical spines (22).…”

Conjoined Twins

“…Twins is not a uncommon phenomenon but conjoined twins are indeed a rarity, since the event occurs only once in 50,000-60,000 births [1]. If twinning is initiated after the embryonic disc and amnionic sac have formed and if the division of the embryonic disc is incomplete, conjoined twins result [2].…”