The review concluded that J-pouch and side-to-end anastomosis were acceptable and safe options after anterior resection for rectal cancer. The authors' conclusions are supported by the data, but should be interpreted with some caution due to the possibility of publication bias and the small number of included trials.

To determine the efficacy of colonic J-pouch compared with side-to-end anastomosis after anterior resection for rectal cancer on operative pressure, volumetric and functional outcomes.

PubMed, EMBASE, CINAHL, and the Cochrane Library were searched from January 1980 to March 2009 with no language restriction; search terms were reported. The related articles function of PubMed was used to identify additional articles. References from relevant articles were also searched.

Randomised controlled trials (RCTs) that compared J-pouch reconstruction with side-to-end anastomosis for rectal cancer were eligible for inclusion. There were no restrictions for patient age or gender. Elective cases were also considered.

Outcomes included hospital stay, operative time, estimated blood loss, overall morbidity, mortality, volume at which the patient first experiences a sensation to defecate, maximal tolerable volume at three and 24 months, use of enemas, bowel medications, pads, incomplete defecation and stool frequency at six and 24 months. Complication rate and mortality was defined as adverse events occurring within 30 days of the operation.

Protocols varied across the included trials, with hand and/or mechanical sutured J-pouch formation (one trial did not specify), curative and/or standard surgery, and stapled and/or hand sewn anastomosis; rectal cancer was from under 10cm to under 15cm from the anal verge. Two trials included patients with stoma. Neoadjuvant treatment was used in two trials; one trial included adjuvant therapy. Radiotherapy was given in one trial.

It appeared that two reviewers independently selected trials for inclusion in the review.

Trials were assessed using a 15-item modified quality score for RCTs (Jadad et al and Chalmers et al). Trials were categorised as being of poor (1 to 5), fair (6 to 10) or good (11 to 15) quality.

The authors did not state how many reviewers assessed study quality.

Data were extracted that allowed the calculation of risk ratios (RRs) for binary data (use of enemas, pads, and bowel medication) and standardised mean differences (SMDs) for continuous data (operation time, hospital stay, blood loss, volumetric and pressure variables).

Two reviewers independently extracted data, which was checked by a third reviewer.

Summary risk ratios and standardised mean differences, with 95% confidence intervals (CIs), were estimated using a fixed-effects model (used in the absence of heterogeneity) and a random-effects model (DerSimonian and Laird). Hedges g statistic was used for the calculation of standardised mean differences. A clinical value for continuous outcomes was also calculated from the standardised mean differences (except where standard deviations from individual trials precluded a meaningful clinical value). Heterogeneity was assessed using the Q-statistic.

A sensitivity analysis was performed in which 0.5 was added to each cell frequency for trials in which no event occurred in either technique. The Mantel-Haenszel fixed-effect method was used to assess robustness and susceptibility to outliers.

Four RCTs were included in the review (n=273 patients; range 48 to 100). Two trials were considered to be of high quality and two trials were deemed to be fair (scores ranged from 6 to 12).

Surgical outcomes: No significant difference was found between J-pouch and side-to-end anastomosis for operative time, blood loss, hospital stay, the development of anastomotic stricture, fistula formation, morbidity and mortality rates. Significant heterogeneity was found for operative time and hospital stay. Clinical values were also presented for these outcomes.

Pressure outcomes: Lower mean postoperative resting pressure was found in the J-pouch group compared with side-to-end anastomosis group, although this was did not reach statistical significance (random effects SMD -1.23, 95% CI -2.47 to -0.01; two RCTs). Evidence of statistical heterogeneity was found (p=0.002). No significant between group difference was found for squeeze pressure; evidence of significant heterogeneity was found.

Volumetric outcomes: No statistical difference was found for volume at which patients first experienced a sensation to defecate (three and 24 months) or the maximal volume tolerated at three and 24 months; evidence of statistical heterogeneity was found.

Functional outcomes: Significantly fewer patients experienced urgency at six months in J-pouch compared with side-to-end anastomosis (RR 0.61, 95% CI 0.39 to 0.96); no evidence of heterogeneity was found (p=0.86). No statistical difference was found for urgency (at 24 months), use of enemas (at six and 24 months), use of pads (at six and 24 months), use of bowel medication (at six and 24 months), incomplete defecation (at six and 24 months), or stool frequency (at six and 24 months).

J-pouch or side-to-end anastomosis were acceptable and safe options after anterior resection for rectal cancer.

The review addressed a focused question and inclusion criteria were clearly defined. Several relevant databases were searched with no language restrictions, but no attempt was made to identify unpublished trials, so there was a possibility of publication bias. Appropriate methods were used to minimise error and bias for study selection and data extraction; it was not clear whether similar methods were undertaken for the assessment of trial quality.

Trial quality was assessed using relevant criteria and the results were clearly presented. Methods used to synthesise trials appeared appropriate.

The authors' conclusions are supported by the data, but should be interpreted with some degree of caution due to the possibility of publication bias and the small number of included trials.

Practice: The authors stated that both J-pouch and side-to-end anastomosis may be considered acceptable and safe options according to surgeon choice.

Research: The authors stated that a larger RCT comparing J-pouch and side-to-end anastomosis would be useful to confirm findings, in particular using operative time as a primary outcome measure and a sample size of at least 70 in each group (providing a difference of 25 minutes, with a power of 95% and significance of 0.01).

Not reported.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.