We found a small but statistically significant and clinically important increased risk for developing multiple sclerosis, in those with tonsillectomy and appendectomy at <= 20 years of age. There was no convincing evidence to support the association of other surgeries and the risk for multiple sclerosis. Well-designed prospective etiological studies, pertaining to the risk for developing multiple sclerosis, ought to be conducted and should include the examination of various surgeries as risk factors.
Could neck veins be damaged by inflammation of the tonsils or the surgical removal of tonsils? Or could the azygous vein or lumbar veins be damaged by the appendectomy? Other surgeries and adenoidectomies had no correlation with MS.