A Systematic Review of Morphometric and Morphological Features of the Sacral Hiatus and Its Clinical Significance
Authors: Muthukumaravel Narayanaswamy, Shree Ranjany Kasinathan, Hemavardhini Ramadoss
Keywords: Sacral hiatus, Morphometry, Morphology, Caudal epidural anaesthesia, Lumbosacral anatomy, Low back pain, Apex position, Anatomical variation.
Abstract:
Background: The sacral hiatus (SH) is of main interest in procedures such as caudal epidural anaesthesia (CEA) and spinal analgesia. Shape and size can vary drastically, and a successful and safe procedure may be hampered due to these variations.
Objectives: This article investigates the human sacral hiatus variations and postulates that differences in the sacral hiatus relate to CEA failure and lower back pain.
Methods: We have reviewed the literature published from 2000 to 2025 from PubMed and Google Scholar. The publications presenting the sacral hiatus anatomical features and association with the procedures were our primary sources. We searched for the trends and possible relationships.
Results: The most frequent shape for SH was an inverted U, followed by an inverted V. Mean length varied from around 21 to 30 mm, with minor differences between males and females and different ethnic groups. Variations in the width, depth, and location of the SH made CEA difficult. Besides, some shapes and locations were associated with low back pain. Conclusion: The sacral hiatus innately differs from one person to another and may impact the efficacy of caudal epidural anaesthesia. Clinicians aware of these differences will have a higher rate of procedural success and a lower rate of complications. Imaging may be a reasonable precaution before performing CEA, especially with such a wide range of anatomical variations.
