Introduction

Caudal duplication syndrome, also known as split notochord syndrome, is a very uncommon congenital condition in which several caudal tissues, embryonic cloaca, and neural tubes show a range of abnormalities, including duplication and deformities. Less than one in 100,000 newborns are born with this rare congenital disease, and there are only about 100 cases known globally [1].

The condition's precise cause is not known [1]. Even though several hypotheses point to incomplete monozygotic twin separation as the etiological cause [2], structural anomalies in the caudal region have also been associated with damage to the caudal cell mass and the posterior gut, abnormal ectoderm-endoderm adhesion during gastrulation [3], polytopic primary developmental field defects [8], somatic and germline mutations in developmental genes [2], and polytopic primary developmental field defects. The HOX gene, specifically HOX10 and HOX11, is thought to be connected to the condition [2]. Misexpression of the genetic components, which normally code for the mammalian appendicular and axial skeleton, may cause the caudal mesenchyme to grow abnormally [2]. The wide range of gastrointestinal (GI), genitourinary (GU), spinal, and limb malformations causes a wide range of symptoms for the disorder.

Gastrointestinal tract anomalies[1]

• Duplication of colon, cecum, ani, appendix, and ileum
• Agenesis, atresia, cyst, herniation, omphalocele, imperforate anus, and rectal fistula
• Meckel’s diverticulum, intestinal malrotation, and situs inversus

Genitourinary tract anomalies[1]

• Duplication of external and internal genitalia, vagina, cervix, bladder, urethra, uterus, ureter, scrotum, and testis
• Bilateral exstrophy of the bladder, cryptorchidism, malrotation, agenesis of the kidney, rectourethral fistula, urinary disturbances including incontinence and retention

Spinal anomalies[1]

• Duplication of lumbar and thoracic vertebrae, sacrum, coccyx, ilium, and spinal cord

(B): Urethrogram and barium follow-through studies showing double bladder [yellow arrows] with separate urethra [red arrows] and double rectum [green arrows].

(C): Coronal T2-weighted MR sequence demonstrates splitting of lower lumbar and sacral segments [red arrow].

(D): Diastematomyelia (Pang type II) and rachischisis [yellow arrow] is also evident in axial T2-weighted FSE MR sequence.

(H): Bowel loops protruding from the abdominal cavity on an axial T2-weighted FSE MR sequence are indicative of an umbilical hernia [yellow arrow].

An ostomy was made as a loop on the skin of the left side of the abdomen since the patient had an imperforate anus. In a vaginoscopy, there were two distinct vaginas, and each hemi-vagina had a distinct cervix. Each urethra had its own bladder and ureteral opening during a cystoscopy or ureteroscopy

A transverse laparotomy was carried out. Two unique columns with discrete mesocolon joined above the peritoneal reflection at the terminal ileum site shared a proximal aperture. The second colon was removed from the ileocecal to the rectum since the first colon had undergone a colostomy at a previous operation site

Case Report 2

A 27-year-old adult male presented to our department with complaints of haematuria and occasional dull lower abdominal pain. He had a limping gait on his left side since childhood. There was no family history of such complaints. He supported three similar incidents in the previous ten years, some of which were connected to UTIs (UTIs).On physical examination, his abdomen was soft with diffuse rebound tenderness but no guarding or rigidity. Hyperactive bowel sounds were present diffusely across the abdomen.

Intravenous pyelography was done. The control film incidentally revealed malformation in the vertebral column and showed duplication

(B): Same study in excretory phase showing malrotated pelvic right kidney [green arrow] and dilated left ureter [yellow arrows].

(C): Pelvic ultrasound showing two urinary bladders [red arrows].

(D): Coronal reconstructed computed tomographic image demonstrates duplication of lower lumbar and sacral segments.

mal-rotated right kidney[annotated] and a small dysplastic left kidney[annotated].

(H): Axial computed tomographic image in delayed phase showing double urinary bladder [red arrows].

(I), (J): Axial and coronal T2-weighted MR sequences demonstrates the splitting of spinal cord from the level of L4-L5[red arrows].

Embryology is suggested to have an intimate association with the development of caudal duplication syndrome.[1] The cloaca is the common embryological source of origin of both the genitourinary and gastrointestinal tracts which is the reason behind the frequent association of anomalies involving these systems[1,2]. The notochord develops from the primitive knot on day 15 following fertilisation, where it invaginates and creates the notochord canal. [1] On day 20, the notochord's ventral wall gradually disintegrates while connections are generated between the amniotic and yolk sacs. [1] The Kovalevsky Canal is one such link. The spinal cord develops from the 23rd to the 25th day of gestation, except for its distal-most portion, where the notochord and neural tube are fused to form the caudal cell mass [1].Many insults directed at the cell mass and hindgut during the stage of development may result in the development of caudal anomalies, one of which is caudal duplication syndrome. The canal of Kovalevsky crosses the caudal cell mass, while the endoderm located anterior to the cell mass develops into the hindgut [1].

Incomplete Kovalevsky's canal regression may also result in the creation of fibrous bands connecting the spinal canal and the hindgut,[5] which may eventually cause diastematomyelia. These bands have the potential to split the notochord, leading to duplicates of the spinal cord and lower spine [4]. Additionally, the adjacent mesoderm is split, resulting in duplicated genitourinary and gastrointestinal tracts. [4] The presence of a variety of malformations, such as spina bifida, dorsal enteric fistulas, enteric cysts, malformed or duplicated colons, bladders, sacrums, and lower spinal cord, can then result from the duplications [1, 9].

Furthermore, a midline pelvic mass defect during pregnancy may prevent the Müllerianduct structuresfrom migrating caudally, which could result in the duplication of the genital tract [1]. It is uncommon to have intestinal duplications that extend into the rectum or anus [1, 6].

The recommended practice of treatment for CDS entails the correction of duplication abnormalities in stages, with an emphasis on anatomical, functional, and aestheticreconstructions [16]. In UB, a septal excision is performed to create a single chamber.