A Child with Three Legs or Conjoint Parasitic Twin?
Turkish Neurosurgery
|June 2, 2026
Summary
Rachipagus parasitic twins are rare congenital anomalies where twins fuse along the spine, often resulting in extra limbs. This study reviews 65 cases, highlighting prevalence and common attachment sites.
Area of Science:
- Medical Genetics
- Developmental Biology
- Congenital Anomalies
Background:
- Rachipagus is a rare congenital anomaly characterized by vertebral fusion in conjoined twins.
- Parasitic twins, a subset of rachipagus, involve one twin being underdeveloped and attached to a developed twin, sometimes with extra limbs.
- The etiology of rachipagus remains largely unknown, necessitating further research.
Purpose of the Study:
- To systematically review existing literature on rachipagus parasitic twins.
- To present a novel case report of rachipagus.
- To analyze the characteristics, prevalence, and anatomical variations of rachipagus anomalies.
Main Methods:
- Systematic literature review of English-language articles from 1952 to 2023.
- Searches conducted in PubMed and Semantic Scholar databases.
- Inclusion criteria focused on cases of rachipagus with excess limbs or masses attached to the spine.
Main Results:
- A total of 65 rachipagus cases were analyzed.
- Females (56.9%) were more affected than males (43.1%).
- Lower limb duplication (63.1%) was most common, frequently in the lumbosacral region (41.5%).
- Over half of the cases (52%) were reported in Asia, followed by Africa (37%).
Conclusions:
- Rachipagus parasitic twins are congenital abnormalities present at birth, involving spinal deformities and accessory limbs.
- This condition arises during embryogenesis.
- The study provides a comprehensive review and highlights a new case of this rare anomaly.
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