compare:					with:
pre-op					pre-op
post-op; bar insertion:
one day	3 wks	infection:	3.5 wks	4 wks	one day	3 wks	infection:	3.5 wks	4 wks
7 wks	8 wks	9 wks	10 wks	12 wks	7 wks	8 wks	9 wks	10 wks	12 wks
4 mths					4 mths