The changes of the numerical-and-size composition and dynamic condition of the sciatic nerve fibers during canine femur lengthening

Comparative study of the changes of the sciatic nerve conductive part under bone injury and specific effect of distraction was performed in the experiments on 17 adult mongrel dogs, which were subjected to femoral osteotomy and neutral osteosynthesis and also to surgical lengthening of femur with a device of original design in which wires and half-pins were used. Using the methods of light and transmission electron microscopy with computer morphometry of half-thin sections it was established that the changes of the numerical-and-size composition of the sciatic nerve fibers were mainly caused by increase of newly formed conductors in number in 42 and 70 days after surgery (this is the end of distraction and 30 days of fixation in the experiments with distraction osteosynthesis). Intermittent clinical symptoms of the descent of the sciatic nerve function first of all were associated with axoplasmatic current disorders, that was demonstrated ultrastructurally by the changes of the cytoskeletal axis cylinders of medullary nerve fibers and nonmedullated ones, and was consistent with the morphometry data of the change of the axoplasmatic compartment of mature medullary fibers.