If a portion of the autonomic nervous system is removed to modify a specific disease process, unrelated physiologic mechanisms will also be affected. The degree to which these other mechanisms may be affected often governs the selection of operative procedures. The results produced by interfering with mechanisms other than those for which the operation is performed might be designated as side-effects or secondary effects. . . .
N Engl J Med 1951; 245:121-130July 26, 1951
http://www.nejm.org/doi/full/10.1056/NEJM195107262450401