Too injured to return to combat flying?

[NickM]

Hopefully this is NOT too silly a question, but what sort of injuries could result in the removal of a JW pilot from combat? Not the obvious things: Blindness, brain injury, spinal column paralysis, multiple amputations; but less 'traumatic': ex: Otto Stambarger, Wilhelm Phillip and Gerd Wiegand were all removed from combat due to injuries--Stambarger recollected his injuries were burns & a severe concussion but 'nothing broken', while Wiegand had his femur shattered; However, Karl Borris practically becames a 'pavement pizza' due to a damaged 'chute, landing hard & breaking many bones but returned to combat & continued to fly to the end of the war, and Gunther Specht lost an eye & had several other serious woundings but kept flying until his death in 1945; Was this just a case of the individual pilots' dedication to serving or where Phillips, Stambarger & Wiegand injured in a 'different' way?
Hope you can clear this question up;

NickM