U2 lead singer Bono had immergency back surgery in München, Germany, after an injury while preparing for his tour. Transit Uranus is exactly conjunct his Mars. Mars-Uranus is one of the aspects that reflect operations. Mars-Uranus is the kind of combination that 'hits you' or 'cuts you' suddenly.
Major events like this don't happen with one transit only. Notice that Jupiter and Uranus trine Midheaven (for a positive and welcome change) and that Neptune is square Midheaven (for an unwanted period of rest and perhaps for the 'sleep' involved. There are many more indications that I leave unmentioned now: just see the chart drawing. There is more info about the artistic talent in the natal chart on Art&Astrology.
astrology home listed the transits and progressions corresponding with a major operation. Mars-Uranus is one of them.
More about Mars-Uranus in natal charts, progressions and transits, see the labels below this post on Astropost.