“…Six stated that they contained groups that were fully matched for age 2,13,15,31,33,37 , five for sex 2,31,35,36,40 , two for both age and sex 2,31 , and two for length of follow-up 35,37 . The mean or median length of followup for both IPAA and IRA groups was at least 36 months in all but one study 38 .…”