Experimental studies on the relation between acceleration and intracranial pressure changes in man
Lissner, H.R.; Lebow, M.; Evans, F.G.
Surgery Gynecology and Obstetrics 111: 329-338
1960
ISSN/ISBN: 0039-6087 PMID: 14417481 Document Number: 3137
1. Twenty-three drops, divided into 5 series of tests, were made with the embalmed bodies of 4 adult white male cadavers. The apparatus and instrumentation, as well as the method of making the drops, are described and illustrated. 2. In the first 3 series of tests, constituting drops 1 through 12, the legs of the cadaver were amputated in the proximal third of the thigh. In the remaining series of tests and drops, the intact body was used. In all test series, the blow was applied to the forehead of the cadaver. The impact surfaces were a 160 pound 3 inch thick steel block, a flat steel plate clamped to the edges, the same plate covered with various types of padding, a 1954 automobile instrument panel, and a 1956 instrument panel. 3. The velocities in the tests were 10.9 miles per hour and 15 miles per hour. The accelerations produced during a test were measured by an accelerometer attached to the occiput. Intracranial pressures in the parietal and temporal regions were measured by pressure transducers. The duration of the pressure was measured in seconds. 4. A 3 foot drop on the 160 pound steel block produced an impact velocity of 10.9 miles per hour and an acceleration varying from 136 to 237 g. The parietal pressure varied from -15 to -25 pounds per square inch, and the temporal pressure from 32 to 42 pounds per square inch. The average time duration of the pressure was 0.006 second. The reason that the pressure gauges registered greater negative values than the standard atmosphere gauge pressure at absolute zero (-14.696 lbs. per sq. in.) was because of the adhesion between the cranial contents and the metallic diaphragm of the pressure gauges. 5. When the body was dropped on a flat steel plate with clamped edges with an impact velocity of 15 miles per hour, the acceleration varied from 104 to 159 g, the parietal pressure from -2 to -15 pounds per square inch, the temporal pressure from 10 to 25 pounds per square inch, and the duration of the pressure from 0.005 to 0.010 second. 6. Use of a 1954 automobile instrument panel with an impact velocity of 15 miles per hour produced a variation of from 65 to 86 g in acceleration, a parietal pressure of - 6 pounds per square inch, and a temporal pressure of 6 to 16 pounds per square inch. The duration of the pressure was 0.008 to 0.016 second. 7. Similar tests on a 1956 automobile instrument panel reduced acceleration from 43 to 63 g, the parietal pressure from -3 to -2 pounds per square inch, the temporal pressure from 5 to 15 pounds per square inch, and the duration of the pressure from 0.005 to 0.022 second. 8. When a polyurethane pad, 3 inches thick, was used on a flat plate with an impact velocity of 15 miles per hour, an acceleration of 84 g and a temporal pressure of 12 pounds per square inch, with a duration of 0.016 second were obtained. The same velocity when the head struck another polyurethane pad on the steel block resulted in acceleration of 70 g, a parietal pressure of 6 pounds per square inch, and a temporal pressure of 16 pounds per square inch. The duration of the pressure was 0.012 second. 9. When a padded 1956 instrument panel was used with an impact velocity of 15 miles per hour, the acceleration amounted to 43 g, the parietal pressure 3 pounds per square inch, and the temporal pressure 9 pounds per square inch. The duration of the pressure was 0.022 second. Another test on the same panel, when unpadded, resulted in an acceleration of 48 g, and a temporal pressure of 14 pounds per square inch, with a duration of 0.016 second. 10. A slightly depressed comminuted fracture was produced in drop 5 in the first series of tests and a linear fracture of the skull in drop 12 in the third series of tests. The first fracture resulted when the head struck the solid steel block after falling through a distance of 3 feet, with an acceleration of -237 g, a temporal pressure of 32 pounds per square inch, and a parietal pressure of -15 pounds per square inch. lasting for 0.006 second. The impact velocity was 10.9 miles per hour. The linear fracture was produced by dropping the head on the same block with the same impact velocity.
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