Browsing by Subject "Cadaver"
- Results Per Page
- Sort Options
Item Open Access A three dimensional nerve map of human bladder trigone.(Neurourology and urodynamics, 2017-04) Purves, J Todd; Spruill, Laura; Rovner, Eric; Borisko, Elyse; McCants, Alden; Mugo, Elizabeth; Wingard, Ainsley; Trusk, Thomas C; Bacro, Thierry; Hughes, Francis MCentral efferent and afferent neural pathways to and from the human urinary bladder are well-characterized, but the location and arborization of these nerves as they traverse the serosa, muscularis, and urothelial layers are not clearly defined. The purpose of this study was to create a three dimensional map of the innervation of the human bladder trigone from the extrinsic perivesical adventitial nerve trunks to the urothelium.A male and a female human bladder were harvested from fresh frozen cadavers and fixed in formalin. The bladder neck and trigone region were serially sectioned (5 μm) and every 20th slide was stained (S100), scanned and aligned to create 3D maps.Nerve penetration into the detrusor muscle occurs with the highest frequency at the bladder neck and interureteric ridge. Nerves traveling parallel to the bladder lumen do so in the adventitia, beyond the outer border of detrusor. In females, the depth of these nerve bands is uniform at 0.7-1.7 cm below the luminal surface, the outer limits of which include the anterior vaginal wall. In the male, depth is more variable owing to detrusor hypertrophy with the minimum depth of nerves approximately 0.5 cm near the interureteric ridge and over 1 cm near the bladder neck.Myelinated neural pathways traversing in the human bladder in the region of the trigone have a discreet regional density. This 3D map of trigonal innervation may provide guidance to more precisely direct therapies for urinary incontinence or pelvic pain. Neurourol. Urodynam. 36:1015-1019, 2017. © 2016 Wiley Periodicals, Inc.Item Open Access Biomechanical comparison of plantar-to-dorsal and dorsal-to-plantar screw fixation strength for subtalar arthrodesis.(Einstein (Sao Paulo, Brazil), 2020-01) Chaudhari, Nileshkumar; Godoy-Santos, Alexandre Leme; Netto, Cesar de Cesar; Rodriguez, Ramon; Dun, Shouchen; He, Jun Kit; McKissack, Haley; Fleisig, Glenn S; Pires, Eduardo Araujo; Shah, AshishOBJECTIVE:To compare screw fixation strength for subtalar arthrodesis. METHODS:Eight matched pairs of cadaver feet underwent subtalar joint arthrodesis with two 7.3mm cannulated screws. Randomization was used to assign screw orientation, such that one foot in each pair was assigned dorsal to plantar screw orientation (DP Group), and the other foot, plantar to dorsal orientation (PD Group). Standard surgical technique with fluoroscopy was used for each approach. Following fixation, each specimen was loaded to failure with a Bionix ® 858 MTS device, applying a downward axial force at a distance to create torque. Torque to failure was compared between DP and PD Groups using Student's t test, with p=0.05 used to determine statistical significance. RESULTS:Statistical analysis demonstrated that the mean torque to failure slightly favored the DP Group (37.3Nm) to the PD Group (32.2Nm). However, the difference between the two groups was not statistically significant (p=0.55). CONCLUSION:In subtalar arthrodesis, there is no significant difference in construct strength between dorsal-to-plantar and plantar-to-dorsal screw orientation. The approach chosen by the surgeon should be based on factors other than the biomechanical strength of the screw orientation.Item Embargo Injury Risks in Behind Armor Blunt Trauma(2024) Op 't Eynde, JoostBody armor protects law enforcement and military personnel from gunshot wounds to the thorax. However, even when a round is stopped, armor can deform into the thorax at high rate and produce injuries. To evaluate armor protection against this behind armor blunt trauma (BABT), an outdated standard developed in the 1970s is currently used. The applicability of the standard to modern design and its biofidelity are questionable. There is a need for biofidelic models and accurate injury criteria for BABT.
To support numerical modeling of high rate insults, material property characterizations are essential. Pure shear tests at high rate and high shear strain were performed on porcine dorsal skin, ventral skin, liver, and lung tissue post-mortem. Synthetic gelatin was subjected to the same shear tests, to evaluate its validity as a tissue surrogate. Instantaneous elastic shear properties of the tissues were determined, and their stress relaxation over short and long timescales. Dorsal skin tissue was found to have the highest shear stiffness, followed by ventral skin, liver, and lung. Synthetic 10-20% gelatin approximates the instantaneous elastic shear properties of porcine dorsal skin but does not show the same viscoelastic relaxation behavior. Synthetic 10% gelatin behaved similarly to 20% gelatin in stress relaxation, but with significantly reduced shear stiffness. Shear moduli of biological tissues increase with increased shear strain, suggesting a non-linear model is appropriate for computational purposes.
To recreate BABT in an experimental setting, a 3D-printed acrylic indenter was developed. This indenter replicates the backface deformation of the body armor into the chest, matching velocity and aerial density of hard body armor. The performance of the indenter was evaluated using the current clay testing standard (n = 52). The obtained deformations in clay match those from previous hard armor experiments. The limitations of using clay as a surrogate for behind armor blunt trauma are discussed in relation to the indenter performance: clay is inconsistent and produces and unpredictable elastic rebound obfuscating the final deformation measurement used in the standard. Equivalent exposures comparing indenter velocity to rifle round velocity are used to translate indenter impacts to in-field scenarios.
Indenter BABT impacts (n = 117) were performed on porcine (n = 16) and human (n = 18) cadavers to establish injury scaling from pig to human. Impactor dynamics were determined using an onboard accelerometer and high-speed video, and rib fractures were assessed using post-test micro-CT imaging and necropsy. Regional injury risk curves were developed for different impact locations on the human cadaver (n = 6) thorax and different injury severity levels, indicating the risk might not be uniform. The injury threshold for anterior ribcage injuries is lower than for the posterior ribcage. The kinetic energy of the impact was scaled according to body mass based on equal velocity scaling, widely used in injury biomechanics. Confidence intervals of injury risk curves substantially overlap for the human and swine cadavers, suggesting that this scaling is appropriate for transferring risk across these species. Residual energy differences of 20 to 30% for similar injury risk between the human and swine cadavers suggest an additional bone quality scaling is desirable since the swine cadavers are generally at an earlier developmental age than available human cadavers. The structural scaling relationships between the human and swine cadavers are valuable in interpreting injury results from live animal BABT tests.
In vivo swine (n = 18) were subjected to BABT impacts to the ribcage. Chest wall and lung injuries were assessed using necropsy and histology, and injury risk curves were developed for different severity injuries based on the kinetic energy of the impact. The resulting injury risks are compared to those obtained for human cadavers. Chest wall injury risk corresponds closely with lung injury risk severity. Injury risks for lateral ribcage impacts in the live swine are close to posterior ribcage impact injury risks in the human cadaver, but injury risks are lower than for frontal impacts in human cadavers. Acoustic emissions of rib fractures were non-invasively detected during BABT impact with the use of hydrophones. Obtained injury risks and fracture detection may guide future armor design and injury monitoring.
A novel modality of lung injury was observed in the live swine impacts. Advancement of the chest wall into the lung tissue at high velocity produces a local compressive shock that can damage alveolar walls and cause bleeding within the lung tissue. A theoretical basis for shock development, experimental shock pressure measurements, and characteristic injuries are presented.