Background: Sacral hiatus is nonfusion of the lamina of a fifth sacral vertebra in midline on the dorsal surface. The caudal epidural block is a common technique to introduce a needle into epidural space through sacral hiatus for surgical anesthesia and analgesia.
Aim: The objective was to study the morphological and morphometric variations of sacral hiatus and sacral canal in human sacra and to provide bony parameters for localization of sacral hiatus as an important landmark to access the epidural space for various clinical procedures successfully.
Materials and methods: The study was executed on 88 dry adult human sacra to scrutinize certain parameters of sacral hiatus and sacral canal including the shape of sacral hiatus, level of apex and base of sacral hiatus, length of sacral hiatus, anteroposterior distance at apex of sacral hiatus and intercornual distance at the base of hiatus.
Results: Inverted ‘U’ shape was most frequent (35.22%) followed by inverted ‘V’ shape (29.24%). The apex and base of sacral hiatus were commonly found at fourth (57.54%) and fifth (92.04%) sacral vertebral level respectively. The mean length of sacral hiatus was 28.17 ± 16.62 mm, the anteroposterior diameter at the apex of sacral hiatus was 6.66 ± 2.71 mm, and the intercornual distance at the base was 16.39 ± 3.44 mm.
Conclusion: Thorough knowledge of relevant anatomy and anatomical variations of sacral hiatus are imperative for clinicians for successful caudal epidural anesthesia.
Clinical significance: During caudal epidural anesthesia, incorrect needle placement in sacral hiatus may result in intraosseous drug toxicity and aspiration. Awareness about sacral hiatus and its variations may improve the understanding of disorders related to sacral nerve injuries.
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