Complex sentence: At the end of 1958, Mark Ravitch was invited to join a medical experts' delegation to the Soviet Union, during which he procured a Soviet stapling instrument and brought it back to the United States.
Split into simpler sentences: At the end of 1958, Mark Ravitch was invited to join a medical experts' delegation to the Soviet Union. On this trip, Ravitch procured a Soviet stapling instrument and brought it back to the United States.