ANATOMIC AND BIOMECHANICAL PROPERTIES OF HUMAN LUMBAR DURA-MATER

Determinants of dural defects subsequent to deliberate or accidental d ural puncture include the equipment, techniques, and the inherent anat omic and biomechanical properties of dura mater. These properties were studied in specimens of human and canine lumbar dura mater in an atte mpt to delineate the structure of the tissue and to characterize its b ehavior in biomechanical terms. Human dura had a longitudinal orientat ion on gross appearance, and was confirmed microscopically to be compo sed of longitudinal lamella of collagen and elastin fibers. Longitudin al tensile strength and stiffness were greater than transverse tensile strength and stiffness, which is consistent with the dura's apparent anatomic structure and functional requirements. Additional biomechanic al testing of the dura demonstrated the property of relaxation which i s a characteristic of a viscoelastic material. Significant differences were observed between human and canine dural properties, suggesting l imited value of this animal model. Integration of these observed anato mic and biomechanical properties of the lumbar dura provides a greater understanding of dural puncture and may explain previous and often co nfusing clinical and experimental findings.