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Year : 2006  |  Volume : 16  |  Issue : 4  |  Page : 783-784
Craniopagus : A preoperative assessment

Department of Radodiagnosis, Kasturba Medical Colllege, Mangalore-1, Karnataka, India

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Date of Submission24-Apr-2006
Date of Acceptance08-Aug-2006

Keywords: Craniopagus, conjoined twin

How to cite this article:
Mahale A, Venugopal A, Kishore M S, Ghiraiya A. Craniopagus : A preoperative assessment. Indian J Radiol Imaging 2006;16:783-4

How to cite this URL:
Mahale A, Venugopal A, Kishore M S, Ghiraiya A. Craniopagus : A preoperative assessment. Indian J Radiol Imaging [serial online] 2006 [cited 2021 Feb 25];16:783-4. Available from:

   Introduction Top

Conjoined twins are rare and estimated prevalence in the literature varies widely, from 1:50,000 to 1:200,000 [1],[2],[3],[4]. The craniopagus type (joined at the head) is exceedingly rare, with an incidence of one in 2.5 million births [5]. Craniopagus twins may be joined at any part of the skull except the face or foramen magnum [4]. The fusion is vertical and parietal in over 60% of cases [4].The oldest medical illustration of conjoined twins is a woodcut circa 1496, which shows twin girls joined at the forehead [6]. In this article we would like to show the usefulness and the necessities of radiological investigation in preoperative assessment of a case of craniopagus.

   Case Report Top

A month old conjoined twin babies were referred to our hospital for further management. There was antenatal ultrasound done for the patient prior to the delivery and babies delivered through caeserian section. The initial discussion regarding the treatment and timing of surgical intervention options were sought out. Then neurosurgical team decided to operate the baby around one and half years of age. The babies were put on tissue expander for one year. Then the patient was send to our radiology department for preoperative assessment.

Initially CT scan has done revealed partial absence of the frontal bones [pic 1]. Then 3D CT reconstruction done to show the relationship of the bones between the babies & the alignment of the skulls. MR showed partially common cranium & partially absent frontal bone with no evidence sharing of brain tissues between the babies [pic 2]. MR also demonstrated no developmental disorders in both the babies' brain tissues. MR angiogram showed sharing of the superior sagittal sinus between the two twins [pic 3]. Then conventional angiogram done demonstrated the sharing of part of sagittal sinus. Then interventional technique using balloon inflation was done on the part of the shared superior sagittal sinus. Then babies observed for 30 minutes to look for any variation in general condition. This was done to look for whether the babies are having dependent supply of one another. There was no dependency of the venous flow noted in both the babies.

   Discussion Top

Cranially conjoined twins (craniopagus) are regarded as one of the rarest human malformations. Craniopagus represents 2 to 6% of conjoined twins and is the rarest type of this disorder [6]. Role and the detail reports of radiological imaging of craniopagus are very rare in literature [8],[9]. The conjoined twins are monozygotic, monoamniotic, and monochorionic [2],[7]. A conjoined twin occurs as a result of failure of complete separation (fission) of a single fertilized ovum 13 and 17 days gestation [2],[4],[7]. Some authors, however, believe that the abnormality is a result of fusion of two separate embryos, with the junction occurring in the open cranial neuropore just before the end of the 4th week after fertilization [10]. The term "Siamese twins" was first popularized following the birth of Eng and Chang Bunker in Siam (now Thailand) in 1811[6].

The role of radiologist can be divided into antenatal and postnatal preoperative assessment. The antenatal diagnosis of conjoined twins can be made with ultrasonography (US) as early as 12 weeks gestation and is important for optimal obstetric management [4]. More accurate evaluation of visceral conjunction is possible from 20 weeks gestation [2],[4].

As far as postnatal preoperative assessment first of all the surgeon and the radiologist team should decide on the time of assessment. The time of assessing the babies is preferably between 15 to 18 months as the brain development has nearly matured. If done at this period this will give us exactly the development, myelination and maturation of the brain.

The foremost radiological assessment to be done is the CT of the head . CT is required for demonstration of the skull vault fusion and the osseous detail [4],[6]. CT also gives us the idea about area of defective skull vault and the soft tissue region after separation. CT show us whether there is any sharing of the brain tissues [6]. MRI establishes the degree of development of brain tissue of both the babies [6] and picks up even minimal interdigitation of brain tissues. Both CT & MRI wouldn't yield information regarding the blood supply and sharing of vasculature. MR angiogram & MR venogram gives us information regarding the cerebral circulation and the dural sinuses [4],[6]. If MR angiogram & MR venogram show sharing of the vasculature go ahead with the conventional angiogram. Conventional angiogram is needed to confirm the exact extend of the sharing of arterial/ venous tree [9],[4]. Then interventional angiogram can be done to look for the dependency of vasculature of one baby from the other one.

To put all these things as flow chart

   References Top

1.Hanson JW. Incidence of conjoined twinning (letter). Lancet 1975; 2:1257.  Back to cited text no. 1    
2.Barth RA, Filly RA, Goldberg JD, Moore P, Silverman NH. Conjoined twins: prenatal diagnosis and assessment of associated malformations. Radiology 1990; 177:201-207.[Abstract]   Back to cited text no. 2  [PUBMED]  
3.Edmonds LD, Layde PM. Conjoined twins in the United States, 1970-1977. Teratology 1982; 25:301-308.[Medline]  Back to cited text no. 3  [PUBMED]  
4.Imaging in the Preoperative Assessment of Conjoined Twins. Radiographics. 2001;21:1187-1208.) RSNA, 2001  Back to cited text no. 4    
5.Craniopagus twins : neuroradiological findings ( CT , Angiography, MRI) - Neuroradiolgy 1988 ; 30(1):11-6  Back to cited text no. 5    
6.Craniopagus joined at the occiput - journal of Neurosurgery oct 2002 ; Vol 97 : No 4   Back to cited text no. 6    
7.Zimmermann AA. Embryological and anatomic considerations of conjoined twins. Birth Defects 1967; 3:18-27.   Back to cited text no. 7    
8.Schindler E, Hajek P.Craniopaqus twins: neuroradiological findings.Neuroradiology 1988;30:11-16.   Back to cited text no. 8  [PUBMED]  
9.Jansen O, Mehrabi VA, Sartor K.Neuroradiological findings in adult canially conjoined twins.J Neurosurg 1998;89:635-639.   Back to cited text no. 9  [PUBMED]  
10.Spencer R: Theoretical and analytical embryology of conjoined twins: Part I: embryogenesis. Clin Anat 13:36-53, 2000   Back to cited text no. 10    

Correspondence Address:
M S Kishore
Department of Radiodiagnosis, K.M.C., Attavar, Mangalore-575001, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0971-3026.32347

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  [Figure - 1], [Figure - 2], [Figure - 3]

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