Biomedical subjects
Publications and source records attributed to Iu B Moiseev.
The localization, causes and severity of 214 "ejection-associated" injuries occurred in 160 pilots are discussed. Spine, upper and lower extremities are affected most frequently. The severe injures prevail (57.8%). The main causes of severe injuries are the impact + Gz accelerations of ejection and the impact + Gz accelerations of landing.
Based on the analysis of available literature, a quantitative estimation of the role of chronic exposure to large aerobatic g-loads on modern aircraft in the risk of degenerative/dystrophic shifts in the spinal lumbar zone of flying personnel was attempted. In the opinion of the author, these g-loads increase the probability of spinal osteochondrosis in 1.5 to 1.75 times.
The purpose of this work was to evaluate early and delayed effects of static mechanical loading of the spine on human tolerance to the ejection g-loads. Experiments with spine segments showed that static pre-loading equivalent to aerobatic accelerations of 8-10 units leads to relative strengthening of vertebra with low tolerance of the longitudinal shock load. Effect of aerobatic accelerations of 5, 6, 7, and 8 units on ejection g-load tolerance was theoretically evaluated.
The article discusses the peculiarities of spinal fractures in catapulted pilots: mechanism of fracture--indirect axial load in combination with front or front-lateral bending; morphological picture--wedge-shaped compression fracture of vertebral body; type of fracture--stable; clinic peculiarities--scanty clinic picture as a rule; localization--mid-thorax section and thoracolumbar zone; number of vertebrae affected--1 as a rule. Diagnostic and treatment recommendations are enclosed. The author also deals with a phenomenon which accompanies the emergency abandon of an aircraft--microlesion of spongy osseous tissue of vertebrae without fracture signs under the influence of shock overload, which later can be the reason of degenerative and dystrophic diseases of spine. Preventive and medical measures are described which assure an adequate rehabilitation of functional state of spine.
Three groups of criteria can be used to describe ultimate tolerance of the "side-to-side" impact loads by test-subject as a pre-shock or pre-traumatic margin of relatively safe exposure. These groups include subjective signs, regulatory (bradycardia, extrasystole, brief respiratory disturbances) and spinal biomechanics deviations. Physiological experiments with 12 essentially healthy young male volunteers showed that ultimate tolerance of 0.13- to 0.16-second exposure to lateral impact loads varied within the range from 15 to 30 units as a result of body motion restraint with shoulder and hip belts and was 1.8-fold lower with the waste belt only.
The biomechanical characteristics of the middle ear of a live man and a corpse (autopsy material) were compared. The conditions were found that provide the adequacy of biomechanical reactions of both objects to changes in the external air pressure.