Abstract

Context: Lumbosacral transitional vertebrae (LSTV) are congenital anomalies that occur due to defect in normal segmentation of the lumbosacral spine during development. This may be either in the form of assimilation of fifth lumbar vertebra with the sacrum (sacralisation), or transition of the first piece of sacral vertebra into the lumbar configuration (lumbarisation). Aims and Objectives: Although presence of LSTV is common in general population but knowledge about its exact clinical implications is still lacking. The primary aim of the present study was to determine the rate of incidence of transitional vertebra and their sex difference (if present) in dried human sacra. Secondary aim was to study these transitional vertebra in detail and correlate these findings clinically. Materials and Methods: A total of fifty unbroken adult sacra were examined (male to female ratio of 3:2). The presence or absence of a lumbar transitional vertebra was noted and classified as incomplete or complete. The sacral indices (SI) of all sacra were measured and values compared between typical and atypical sacra with LSTV as well as between male and female sacra. Results: Out of fifty sacra, six sacra (12%) showed presence of LSTV. Among them, four (8%) showed sacralisation of the fifth lumbar vertebra and two (4%) showed lumbarisation of first sacral vertebra. Among the four sacra showing sacralisation, two showed incomplete fusion and two showed complete fusion of fifth lumber vertebra with sacrum. LSTV was found to be more common in male than female. Sacralisation was seen only in male sacra while lumbarisation only in female sacra. The difference in the mean SI of typical sacra (97.76±4.08) and sacra with LSTV (83.69±2.38 and 98.11±1.52 for sacralised and lumbarised sacra respectively) was found to be statistically significant (p<0.05) and that between the male (94.55±5.70) and female (100.14±3.42) sacra was found to be highly significant (p<0.01). Conclusion: Presence of LSTV has many clinical and forensic implications and its knowledge is important for orthopaedic surgeons, neurosurgeons, forensic experts and also to radiologists.

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