Multidisciplinary surgical approach to a surviving infant with sirenomelia

Sirenomelia in Twin Pregnancy: A Case Report

Sirenomelia is a rare congenital disorder that was once thought to be a severe case of caudal regression but is now thought to be entirely separate. It is often referred to as the "mermaid syndrome" because it causes the lower limbs to atrophy to varying degrees, giving the impression of a mermaid's tail or fin. The syndrome is often viewed as fatal due to the accompanying visceral deformities. Our case was a live born, delivered at term by caesarean section, to a 30-year-old third gravida having twin pregnancy. Examination of the baby revealed caudal dysgenesis with fusion of lower limbs, non-identifiable external genitalia and anus. The infant survived for 11 hours after birth. We report this case due to their rarity and term live birth. While sirenomelia is uncommon, the absence of distinct lower limbs on ultrasonography in the presence of oligo or anhydramnios may prompt consideration of the diagnosis of sirenomelia.

Surgical Management of Sirenomelia: A Case Study

Background

Sirenomelia is a rare congenital condition characterized by fusion of the lower limbs. Patients with sirenomelia generally do not survive long after birth because the condition is associated with multisystem organ dysfunction due to developmental anomalies. Considering the low incidence and few cases surviving the neonatal period, there is minimal understanding regarding the surgical management of sirenomelia. We present a unique case of an infant born with type 1 sirenomelia, absence of external genitalia, presence of a cloaca, absence of the bladder, and presence of an imperforate and vestigial anus, who not only survived the birth process, but, at the age of 11 months, was determined to be a candidate for surgical separation of the lower extremities.

Methods

This case was approached much like a dorsal rectangular flap syndactyly release. Large Z-plasty flaps were designed and raised, and the soft tissue within the skin bridge was meticulously dissected to preserve anatomy and to provide adequate skin flaps without perineal skin grafting. A quadrangular flap was designed to reconstruct the perineum and produce a neo-vulva using de-epithelialization.

Results

Successful lower extremity separation was achieved. There were no major postoperative complications. The patient progressed with lower extremity function, and eventually achieved independent ambulation.

Conclusions

Management of sirenomelia is incredibly challenging, and data to guide surgical management are limited. This report details our approach to a successful lower extremity separation, repair, and neo-vulvar reconstruction in a case of type I sirenomelia.

Six-month survival of a monochorionic monoamniotic twin with sirenomelia

BACKGROUND

Sirenomelia is a congenital malformation of the lower body characterized by a single midline lower limb and severe urogenital and gastrointestinal malformations. Sirenomelia is rare (estimated incidence of approximately 1/100,000) and usually lethal in the perinatal period.

CASE

A 2,042 g Japanese male infant, one of monochorionic monoamniotic twins, was born at 34 weeks of gestation by elective caesarean section. Sirenomelia was prenatally diagnosed. Single midline lower limb, bilateral dysplastic kidneys, an omphalomesenteric fistula, colon atresia, imperforate anus, indiscernible genital structures, and myelomeningocele were detected at birth. The amniotic fluid volume was normal throughout the pregnancy course, which led to appropriate lung maturation of the twin with sirenomelia. Although renal replacement therapy was initiated soon after birth, stable peritoneal dialysis was difficult because of the limited intraperitoneal space, and the infant frequently developed peritonitis. He died of sudden cardiorespiratory arrest at 6 months of age. Postmortem examination showed bilateral dysplastic kidneys, agenesis of the ureters and urinary bladder, abnormal branching and agenesis of the distal colon, bilateral inguinal hernias, and small testes.

CONCLUSION

Infants with sirenomelia, even those with end-stage kidney disease at birth, may survive if they have a stable cardiorespiratory status at birth and renal replacement therapy is appropriately initiated.

In search of the earliest images of symmelia in works of art

Symmelia (alias sirenomelia, mermaid malformation) is one of the most distinctive malformations which, not surprisingly, has attracted the attention of many artists, writers and other observers of the human condition. Works of art depicting symmelia date back at least two millennia. Some are anatomically based while others are more fanciful creations intended to stir the imagination. The figure of Atargatis as a mermaid on a first century BC coin is one of the earliest known images of symmelia. A nearly 2000-year-old Native American pottery figure representing an infant with symmelia is another.

Successful Expectant Management of the Anomalous Fetus with Sirenomelia in Twin Pregnancy: A Case Report and Literature Review

Background

Sirenomelia is a rare congenital defect. Its management during pregnancy and after delivery is becoming a controversial issue because of its complex nature and management outcome. The possibility of expectant management in the sirenomelia twin drove us to write this case report.

Case Presentation

We report a case of successful expectant management in twin sirenomelia which was diagnosed in the second trimester. Prenatal counseling of the couple by a multi-disciplinary team regarding the diagnosis, treatment, and prognosis of the sirenomelia twin was done. The mother gave birth, at term, to one normal and one sirenomelia neonate by cesarean section.

Conclusion

Expectant management of sirenomelia one in twin pregnancy is advisable in a resource-limited setting.

A Rare Case Report of Sirenomelia Following Intracytoplasmic Sperm Injection Embryo Transfer

Sirenomelia is a very rare developmental abnormality which is characterized by fusion of lower limb to form a single limb. This condition is often associated with internal organ abnormality and is considered incompatible with life. Sirenomelia is sporadically reported from across the world, but no case associated with artificial reproductive technology (ART) has not been reported. We report a case of sirenomelia in a 29-year old woman who conceived by ART, which to our knowledge is the first reported case in ART. The defect was detected early during first trimester and the pregnancy was terminated.

Sirenomelia associated with an anterior abdominal wall defect: a case report

Background

Sirenomelia is a rare and fatal congenital defect. The rarity of this case and its association with abdominal total wall defect drove us to report this case.

Case presentation

We report a rare case of sirenomelia characterized by lower limb fusion, thoracolumbar spinal anomalies, sacrococcygeal agenesis with a rudimentary tail, and genitourinary and anorectal atresia. Coexistent anterior abdominal wall defect in this case highlights its fatalness because of complications associated with the malformation.

Conclusions

Sirenomelia syndrome has seldom been reported. The present case highlights the rare atypical association of sirenomelia with anterior abdominal wall defect. Because the investigations were done in a low-resource setting, the etiology regarding this case remains unclear.

Fusion of lower limbs with severe urogenital malformation in a newborn, a rare congenital clinical syndrome: case report

Background

Fused lower limbs combined with severe urogenital malformation, also known as sirenomelia, is a rare congenital clinical syndrome. The etiology is unknown, and the outcome for the affected fetus is rather uncertain.

Case report

Mrs RB, a Kuwaiti woman primigravida, married to a non-consanguineous husband, had uneventful antenatal care in a private health service, until she was admitted to the Maternity Hospital, Kuwait, at 31 weeks of gestation with a 3-hour history of ruptured membranes. She had a negative family history for diabetes mellitus, and her past surgical/medical/gynecological history was noncontributory. General physical examination revealed a healthy parturient with normal vital signs, clear lungs and normal heart sounds. Obstetric examination revealed a fundal height compatible with the gestational age; there was a single living fetus in breech presentation; she was not in labor. The mother was managed conservatively with antibiotics and dexamethasone injections. Labor ensued later, progressing rapidly to the second stage. Assisted breech delivery was performed, and a live baby, birth weight 1570 g and Apgar score 3/9, was delivered. The neonate had multiple congenital abnormalities, including fusion of both lower limbs, ambiguous genitalia, cloacal anomaly and tracheoesophageal fistula. The neonate was admitted to the neonatal intensive care unit, fully investigated, managed medically and surgically and eventually discharged home after a hospital stay of 123 days for further management.

Conclusion

A case of peculiar fetal anomaly called sirenomelia, the first case in Kuwait, has been presented. Survival of such babies requires costly management with average results.

Sirenomelia with associated systemic anomalies: an autopsy pathologic illustration of a series of four cases

Sirenomelia, a developmental defect involving the caudal region of the body, is associated with several internal visceral anomalies. We report a detailed spectrum of anomalies in an autopsy study of four fetuses with sirenomelia (gestational ages - 20, 21, 22.4, and 22.5 weeks). Three of the fetuses had single umbilical artery, with genitourinary and gastrointestinal anomalies. Central nervous system anomalies were evident in two of the fetuses, with alobar holoprosencephaly in one and lumbar meningomyelocele in another. The most common gastrointestinal anomaly was blind ended gut (imperforate anus), while esophageal atresia and omphalocele were noted in one case each. Renal hypoplasia was seen in two fetuses, renal agenesis in one and cystic renal dysplasia was noted in one case. Literature regarding pathogenesis of this condition is briefly discussed.

Sirenomelia: a new type, showing VACTERL association with Thomas syndrome and a review of literature

Sirenomelia or "mermaid syndrome" is a rare congenital anomaly known since antiquity. This congenital anomaly is defined as a polymalformative syndrome that associates major muscle and skeleton abnormalities (unique lower limbs) with visceral abnormalities (unilateral or bilateral renal agenesis, anomalies of the abdominal vascularisation). This phenotype, typical of sirenomelia syndrome, may be more or less severe. The pathogenic mechanisms of this syndrome are still debated and its etiology remains unknown. We report here a new type of sirenomelia that we observed in a fetus belonging to the collection of the Department of Anatomy of Reims, which led us to perform a comprehensive review of the literature on the subject: this type has never been reported and cannot be classified according to the Stocker and Heifetz classification. Moreover, this case also presents a VACTERL association with Thomas syndrome.

Sirenomelia phenotype in bmp7;shh compound mutants: a novel experimental model for studies of caudal body malformations

Sirenomelia is a severe congenital malformation of the lower body characterized by the fusion of the legs into a single lower limb. This striking external phenotype consistently associates severe visceral abnormalities, most commonly of the kidneys, intestine, and genitalia that generally make the condition lethal. Although the causes of sirenomelia remain unknown, clinical studies have yielded two major hypotheses: i) a primary defect in the generation of caudal mesoderm, ii) a primary vascular defect that leaves the caudal part of the embryo hypoperfused. Interestingly, Sirenomelia has been shown to have a genetic basis in mice, and although it has been considered a sporadic condition in humans, recently some possible familial cases have been reported. Here, we report that the removal of one or both functional alleles of Shh from the Bmp7-null background leads to a sirenomelia phenotype that faithfully replicates the constellation of external and internal malformations, typical of the human condition. These mutants represent an invaluable model in which we have analyzed the pathogenesis of sirenomelia. We show that the signaling defect predominantly impacts the morphogenesis of the hindgut and the development of the caudal end of the dorsal aortas. The deficient formation of ventral midline structures, including the interlimb mesoderm caudal to the umbilicus, leads to the approximation and merging of the hindlimb fields. Our study provides new insights for the understanding of the mechanisms resulting in caudal body malformations, including sirenomelia.

Sirenomelia in a Cameroonian woman: a case report and review of the literature

Sirenomelia is a rare congenital malformative disorder characterized by fusion of the lower limbs giving a characteristic mermaid-like appearance to the affected foetus. We report a case of sirenomelia occurring in a 19 year old Cameroonian woman following premature rupture of membranes and associated cord prolapse. This is the first documented case in this country. We highlight some of the cultural myths associated with this disorder and discuss our findings relative to the present literature and related controversies on its etiopathogenesis.

Sirenomelia: an epidemiologic study in a large dataset from the International Clearinghouse of Birth Defects Surveillance and Research, and literature review

Sirenomelia is a very rare limb anomaly in which the normally paired lower limbs are replaced by a single midline limb. This study describes the prevalence, associated malformations, and maternal characteristics among cases with sirenomelia. Data originated from 19 birth defect surveillance system members of the International Clearinghouse for Birth Defects Surveillance and Research, and were reported according to a single pre-established protocol. Cases were clinically evaluated locally and reviewed centrally. A total of 249 cases with sirenomelia were identified among 25,290,172 births, for a prevalence of 0.98 per 100,000, with higher prevalence in the Mexican registry. An increase of sirenomelia prevalence with maternal age less than 20 years was statistically significant. The proportion of twinning was 9%, higher than the 1% expected. Sex was ambiguous in 47% of cases, and no different from expectation in the rest. The proportion of cases born alive, premature, and weighting less than 2,500 g were 47%, 71.2%, and 88.2%, respectively. Half of the cases with sirenomelia also presented with genital, large bowel, and urinary defects. About 10-15% of the cases had lower spinal column defects, single or anomalous umbilical artery, upper limb, cardiac, and central nervous system defects. There was a greater than expected association of sirenomelia with other very rare defects such as bladder exstrophy, cyclopia/holoprosencephaly, and acardia-acephalus. The application of the new biological network analysis approach, including molecular results, to these associated very rare diseases is suggested for future studies.

A clinical and experimental overview of sirenomelia: insight into the mechanisms of congenital limb malformations

Sirenomelia, also known as sirenomelia sequence, is a severe malformation of the lower body characterized by fusion of the legs and a variable combination of visceral abnormalities. The causes of this malformation remain unknown, although the discovery that it can have a genetic basis in mice represents an important step towards the understanding of its pathogenesis. Sirenomelia occurs in mice lacking Cyp26a1, an enzyme that degrades retinoic acid (RA), and in mice that develop with reduced bone morphogenetic protein (Bmp) signaling in the caudal embryonic region. The phenotypes of these mutant mice suggest that sirenomelia in humans is associated with an excess of RA signaling and a deficit in Bmp signaling in the caudal body. Clinical studies of sirenomelia have given rise to two main pathogenic hypotheses. The first hypothesis, based on the aberrant abdominal and umbilical vascular pattern of affected individuals, postulates a primary vascular defect that leaves the caudal part of the embryo hypoperfused. The second hypothesis, based on the overall malformation of the caudal body, postulates a primary defect in the generation of the mesoderm. This review gathers experimental and clinical information on sirenomelia together with the necessary background to understand how deviations from normal development of the caudal part of the embryo might lead to this multisystemic malformation.