Six RCTs (n=648 patients) were included in the review. Sample sizes in the trials ranged from 30 to 268 patients. The median Jadad score was 2.5 points: three trials scored 3 points; one trial scored 2 points; and two trials scored 1 point. Randomisation was described in four trials. Three trials described drop-outs and withdrawals.
Early postoperative outcomes: There were no statistically significant differences between the treatments in the occurrence of early postoperative events of anastomotic leakage, chest infection, wound infection, anastomotic stricture or fistula.
Functional outcomes: At six months follow-up, there was a statistically significant benefit observed with the transverse coloplasty pouch for nocturnal leakage (OR 5.88, 95% CI 1.22, 28.55; two trials, n=118), but there were no statistically significant differences in stool frequency and stool fragmentation. There was no statistically significant heterogeneity for these functional outcomes.
At 12 months follow-up, the use of the transverse coloplasty pouch was found to be significantly associated with benefits in stool frequency (WMD -0.39, 95% CI -0.50 to -0.29; two trials, n=118). There were no differences between treatments for stool fragmentation or nocturnal leakage. There was no statistical heterogeneity.
Anorectal physiology: There were no significant differences at six months follow-up in resting pressure, squeeze pressure, rectal threshold, and maximal (neo) rectal volume. At 12 months, there were significant differences favouring the colonic J-pouch in maximal rectal volume (WMD -15.02mL, 95% CI -24.85 to -5.19), with no significant heterogeneity. There were no other differences in outcomes between the pouch types for anorectal physiology at 12 months follow-up, although statistical heterogeneity was present across most of these outcomes. There were discrepancies in reporting between the text and tables for maximal rectal volume at 12 months.