Dutch to English Medical Medical (general)

Hi esteemed colleagues,

I came across what I think is an acronym in a medical report:
Some context:
Scrotum: slank, geen roodheid of zwelling zichtbaar, niet warm.
Beiderzijds testis gb, laag scrotaal, alleen pijnlijk/gevoelig bij palpatie van linker epididymis, geen evidente zwelling, liezen gb.
AO:
Used: schoon

Really not sure what Used could refer to. And 'schoon'?

Thanks for any help.