How safe are the vigorous neck manipulations done by chiropractors?

The chiropractor had just worked on Lynne Beliveau’s neck when she became dizzy, unable to see or move. Rushed to the hospital, Beliveau had a shunt inserted to relieve pressure caused by swelling in her brain. The Ashburn woman suffered a series of strokes and today, eight years later, the 41-year-old mother of three suffers from constant vertigo.

Source/more:
https://www.washingtonpost.com/national/health-science/how-safe-are-the-vigorous-neck-manipulations-done-by-chiropractors/2014/01/06/26870726-5cf7-11e3-bc56-c6ca94801fac_story.html