Effect of young's modulus of porcine ligamentum flavum on the epidural needle insertion

Abstract The purpose of the present study was to determine the geometrical and biomechanical properties of human cervical spine ligaments from the axis to the first thoracic level. A total of 33 human cadavers were used. Geometrical data included the length and cross-sectional area measurements. Biomechanical properties included force, deflection, stiffness, energy, stress, strain, and Young’s modulus of elasticity. These data were obtained for the anterior longitudinal ligament, posterior longitudinal ligament, joint capsules, ligamentum flavum, and interspinous ligament. Geometrical characteristics were determined using cryomicrotomy techniques and biomechanical properties were obtained using in situ failure tensile testing. Force-deformation responses of each ligament type and at each spinal level were normalized. The joint capsules and ligamentum flavum exhibited the highest area of cross-section (p < 0.005). The longitudinal ligaments responded with the highest length measurements. The strain parameters were higher for the ligaments of the posterior complex, i.e., interspinous ligament, joint capsules, and ligamentum flavum, than for the ligaments of the anterior complex, i.e., the anterior and posterior longitudinal ligaments. In contrast, the failure stress and Young’s modulus of elasticity were higher for the anterior and posterior longitudinal ligaments compared to the ligaments of the posterior complex. These findings delineate the relative contribution of the anterior and posterior ligaments in the human cervical spine.

Download Full-text

Friction Analysis in Needle Insertion Into Soft Tissue

Volume 1: Additive Manufacturing; Advanced Materials Manufacturing; Biomanufacturing; Life Cycle Engineering; Manufacturing Equipment and Automation ◽

10.1115/msec2021-63715 ◽

2021 ◽

Author(s):

Yingda Hu ◽

Murong Li ◽

Yong Lei

Keyword(s):

Friction Coefficient ◽

Young’S Modulus ◽

Friction Force ◽

Young's Modulus ◽

Surface Friction ◽

Needle Insertion ◽

Contact Forces ◽

Diagnostic Methods ◽

Tissue Pressure ◽

Preoperative Diagnostic

Abstract As one of the preoperative diagnostic methods, needle insertion is widely used for its safety and effectiveness. Recently, robotic needle insertion systems have been under active developments. Hence needle insertion experiments are essential for system verifications, in which the interactions between needle and tissue is a major focus for needle-tissue interactive models, and the friction between the needle and tissue is an important factor. In these experiments, the friction coefficient can be affected by many factors, such as insertion speed, needle-tissue deformation and contact forces. In this paper, to study and analyze the influence of various variables on friction force and friction coefficient, three variables, i.e., tissue pressure on needle, needle insertion velocity and Young’s modulus of the tissue, are systematically studied by constructing a testbed, in which the radial surface friction is converted into equivalent plane friction based on the assumption that the distribution of the normal force and friction force on the needle is uniform for the whole needle outer surface. The experimental results show that the variation range of friction coefficient is 0.122–0.341. The friction coefficient decreases with the increase of pressure and increases with the increase of velocity, while Young’s modulus have a small effect on the friction coefficient.

Download Full-text

Eyes in the Needle

Anesthesiology ◽

10.1097/aln.0b013e31821b5746 ◽

2011 ◽

Vol 114 (6) ◽

pp. 1320-1324 ◽

Cited By ~ 25

Author(s):

Huihua K. Chiang ◽

Qifa Zhou ◽

M. Susan Mandell ◽

Mei-Yung Tsou ◽

Shih-Pin Lin ◽

...

Keyword(s):

Epidural Catheter ◽

Dura Mater ◽

Epidural Space ◽

Dural Puncture ◽

Ligamentum Flavum ◽

Needle Insertion ◽

Epidural Needle ◽

Average Weight ◽

Ultrasound Probe ◽

Epidural Catheters

Background Epidural needle insertion is usually a blind technique where the rate of adverse events depends on the experience of the operator. A novel ultrasound method to guide epidural catheter insertion is described. Methods An ultrasound transducer (40 MHz, a -6 dB fractional bandwidth of 50%) was placed into the hollow chamber of an 18-gauge Tuohy needle. The single crystal was polished to a thickness of 50 μm, with a width of 0.5 mm. Tissue planes were identified from the reflected signals in an A-mode display. The device was inserted three times into both the lumbar and thoracic regions of five pigs (average weight, 20 kg) using a paramedian approach at an angle of 35-40°. The epidural space was identified using signals from the ligamentum flavum and dura mater. Epidural catheters were placed with each attempt and placement confirmed by contrast injection. Results The ligamentum flavum was identified in 83.3% of insertions and the dura mater in all insertions. The dura mater signal was stronger than that of the ligamentum flavum and served as a landmark in all epidural catheter insertions. Contrast studies confirmed correct placement of the catheter in the epidural space of all study animals. Conclusions This is the first study to introduce a new ultrasound probe embedded in a standard epidural needle. It is anticipated that this technique could reduce failed epidural blocks and complications caused by dural puncture.

Download Full-text

Geometric and Mechanical Properties of Human Cervical Spine Ligaments

Journal of Biomechanical Engineering ◽

10.1115/1.1322034 ◽

2000 ◽

Vol 122 (6) ◽

pp. 623-629 ◽

Cited By ~ 186

Author(s):

Narayan Yoganandan ◽

Srirangam Kumaresan ◽

Frank A. Pintar

Keyword(s):

Mechanical Properties ◽

Cervical Spine ◽

Young’S Modulus ◽

Ligamentum Flavum ◽

Young's Modulus ◽

Statistical Significance ◽

Posterior Longitudinal Ligament ◽

Cross Sectional ◽

Interspinous Ligament ◽

Biomechanical Behavior

This study characterized the geometry and mechanical properties of the cervical ligaments from C2–T1 levels. The lengths and cross-sectional areas of the anterior longitudinal ligament, posterior longitudinal ligament, joint capsules, ligamentum flavum, and interspinous ligament were determined from eight human cadavers using cryomicrotomy images. The geometry was defined based on spinal anatomy and its potential use in complex mathematical models. The biomechanical force-deflection, stiffness, energy, stress, and strain data were obtained from 25 cadavers using in situ axial tensile tests. Data were grouped into middle (C2–C5) and lower (C5–T1) cervical levels. Both the geometric length and area of cross section, and the biomechanical properties including the stiffness, stress, strain, energy, and Young’s modulus, were presented for each of the five ligaments. In both groups, joint capsules and ligamentum flavum exhibited the highest cross-sectional area p<0.005, while the longitudinal ligaments had the highest length measurements. Although not reaching statistical significance, for all ligaments, cross-sectional areas were higher in the C5–T1 than in the C2–C5 group; and lengths were higher in the C2–C5 than in the C5–T1 group with the exception of the flavum (Table 1 in the main text). Force-deflection characteristics (plots) are provided for all ligaments in both groups. Failure strains were higher for the ligaments of the posterior (interspinous ligament, joint capsules, and ligamentum flavum) than the anterior complex (anterior and posterior longitudinal ligaments) in both groups. In contrast, the failure stress and Young’s modulus were higher for the anterior and posterior longitudinal ligaments compared to the ligaments of the posterior complex in the two groups. However, similar tendencies in the structural responses (stiffness, energy) were not found in both groups. Researchers attempting to incorporate these data into stress-analysis models can choose the specific parameter(s) based on the complexity of the model used to study the biomechanical behavior of the human cervical spine. [S0148-0731(00)01006-2]

Download Full-text