A Morphometric Study of Sacral Hiatus and its Importance in Caudal Epidural Anaesthesia

Abstract

Introduction : The caudal epidural anaesthesia is a process in which medications are injected into epidural space to provide analgesia and anaesthesia in various clinical procedures. The technique of caudal epidural block entirely depends upon exact localization of sacral hiatus through which clinicians access the epidural space. The precise knowledge about different anatomical variations related to the sacral hiatus increase its success rate. Aim: To study the different anatomical variations and morphometry of the sacral hiatus in the population of Bihar that is useful in caudal epidural anaesthesia. Materials and Methods: The present study has been carried out on 124 undamaged adult human sacra of which age and sex were not predetermined. Only fully ossified, dried, macerated and thoroughly cleaned sacra which were complete in all respects, in order to give the correct observations, were included in the study while the sacra having any deformity or pathology were excluded. The different metric parameters were measured with the help of digital vernier caliper. The various shapes of sacral hiatus was also observed. The software GRAPH PAD PRISM version 4.03 is used for statistical analysis of data. Results : The most common shape of sacral hiatus recorded in the present study is Inverted U (44.36%) followed by Inverted V (35.48%). The least common shape is bifid (4.03%). In 2.42% cases sacral hiatus is absent. Apex of the sacral hiatus is mostly seen at the level of 4th sacral vertebra (71.77%), while base is commonly located at the level of 5th sacral vertebra (79.84%). The mean length of sacral hiatus is 26.92 ± 12.91 mm. The mean transverse width and mean anteroposterior diameter of SH at the apex are 12.14 ± 3.89 mm and 5.39 ± 1.96 mm respectively. Conclusion : The different variation of shape and size of sacral hiatus should always kept in mind while giving caudal epidural anaesthesia and analgesia. These variations may occur due to different genetic and racial factors.

Keywords

• anatomical variations
• sacrum
• sacral canal
• sacral cornua