TMSS Medical College Journal

Background: Anatomy of sacral hiatus has clinical importance during caudal epidural block. Single bony landmark may not help in locating sacral hiatus because of anatomical variation. This study determines the landmarks for CEB (Caudal epidural block) along with the apex of sacral hiatus and equilateral triangle, were measured. So, the knowledge of anatomy of sacral hiatus is significant while administration of caudal epidural anesthesia and it may help to improve its success rate. Materials and Methods: This study was performed on 57 out of 60 dry adult human sacra of unknown sexes from the stocks of Anatomy laboratory of Sylhet MAG Osmani Medical College, Sylhet from July 2017 to June 2018. Sex determination of the collected unknown sacra was done by using discriminant function analysis and found 28(49.12%) male and 29(50.88%) female using digital slide calipers and measuring tape different parameters were measured. Results: Right and left superolateral sacral crests of the sacrum were taken as two points on dorsal surface of sacrum (forming the base of a triangle) because posterior superior iliac spines impose on the superolateral sacral crests. The distance between the two superolateral sacral crests (base of a triangle) were 60.13mm (range 57-70 mm), the distance between the right Superolateral sacral Crest and the apex were 76.11 mm (range, 56-94mm), the distance between the left Superolateral sacral Crest and the apex 78.53 mm (range, 56-102mm) respectively. Students ttest was applied to reach the level of significance where necessary. A probability value (p) of less than 0.05 was considered statistically significant. Conclusion: The apex of sacral hiatus and equilateral triangle that is located between the apex of sacral hiatus and superolateral sacral crests was found. That will certainly be use in determining the location of the sacral hiatus during CEB.

For analgesia and anesthesia in various clinical procedures, we need caudal epidural block which involves injection of a drug into the epidural space through the sacral hiatus. The sacral hiatus is an arched defect in the posterior wall of the sacral canal formed by the failure in fusion of the laminae of the fifth (and sometimes fourth) sacral vertebra dorsally. The remnants of the inferior articular processes of the fifth sacral vertebra elongate downward on both sides of the hiatus, extending from its apex as the sacral cornua'. Sacral cornua felt at the upper end of natal cleft 5 cm above the tip of the coccyx’. The dural sac and subarachnoid space usually extends to the level of the $2 segment of the sacrum but the dural sac may ends as high as the LS or to S3. Entry into sacral canal should be safe to prevent dural sac puncture and protect surrounding structures.” * The sacral hiatus and the cornua are palpable landmarks employed in caudal epidural injections. ® But in case of obese and adults it is sometimes difficult to determine the anatomical location of the sacral hiatus and the caudal epidural space’. Incorrect needle placement has been reported to occur in up to 36% of cases, even with experienced operators.® The success rate of CEB is based on determination of the landmarks by the clinician. The main goal of this study was to identify additional anatomical landmarks in cases where the sacral cornua could not be identified and measurements that may enhance the location of the apex of the sacral hiatus in practical solution for CEB. Measurements on dry sacral bones determine anatomical landmarks that may be used during CEB procedures.