Not too long ago I was asked by a patient if the hair loss they noticed could be related to their the significant spinal fusion surgery they recently had. The short answer is yes: The stress of recovering from surgery can cause our bodies shunt nutrients to our heart, lungs, muscles and other vital organs. As a result, hair may be weakened. See the details in this article by an Orange County plastic surgeon: https://drnichter.com/hair-loss-after-surgery-explained/