This review concluded that there is no benefit of any other technique for hepatic resection in adults compared with clamp-crushing in terms of morbidity, mortality and transfusion rates. The number of included trials, participants and event rates, as well as reported clinical heterogeneity, limits robust conclusions. Results should be interpreted with caution.

To compare the clamp-crushing technique with any subsequently introduced transection technique in patients undergoing elective liver resection.

The following databases were searched without language restriction from inception (final search date not reported): MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials and the Science Citation Index. Search terms were broadly described. Experts in the field were also contacted and the references of relevant articles were checked for any additional studies.

Randomised controlled trials (RCTs) comparing clamp-crushing technique with any other parenchymal transection technique in adults undergoing elective liver resection were eligible for inclusion in the review. Studies using a laparoscopic approach were excluded.

All included trials were parallel-group design and one trial included a four-arm study design. Trials compared clamp-crushing with the following devices: ultrasonic dissector using ultrasonic energy; dissector sealer using saline-linked radiofrequency energy; pressurised water-jet method; radiofrequency-assisted liver resection using radiofrequency electrodes for tissue coagulation before common scalpel transection; sharp transection with scalpel; and device using bipolar radiofrequency in combination with compression. A variety of methods of vascular control were used.

The primary outcome was overall morbidity (defined as the development of at least one complication). A wide range of secondary outcomes were also reported in the paper, including biliary leakage, transfusion rate and mortality.

The majority of trials included patients with and without liver cirrhosis and chronic liver disease. One trial included only patients without cirrhosis. The included trials were conducted in a number of different countries: Japan, Korea, Switzerland, Italy, and Greece.

Two reviewers independently selected studies for inclusion in the review. Any disagreements were resolved by consensus with a third reviewer.

Trials were assessed in terms of the following criteria: sample size calculation; generation of allocation sequence; allocation concealment; blinding; reported protocol deviation, withdrawals and drop-outs; and efficacy of randomisation. The highest possible score was eleven.

Two reviewers independently assessed the methodological quality of the included studies and any disagreements were resolved by consensus.

Mean or median values were extracted for each outcome of interest, where reported. Relative risks and associated 95% confidence intervals (CI) were calculated for dichotomous data. The authors of the included trials were contacted where additional information was required.

Two reviewers independently extracted a predefined set of data and any disagreements were resolved by consensus.

Data were combined in a meta-analysis using a random-effects model and summary estimates were reported as relative risks with associated 95% confidence intervals (CI). Data presented as median were not included in the meta-analysis. Analysis was stratified by transection technique with which clamp-crushing was compared. All results were checked for clinical and statistical heterogeneity. Sources of clinical heterogeneity included varying or missing information for trial interventions, concomitant care and trial populations. Statistical heterogeneity was assessed using I² statistic (values of greater than 50% indicating the presence of heterogeneity). Publication bias was assessed based on visual inspection of funnel plots.

Seven RCTs were included in the review (n=554 patients). Trial quality was considered to be moderate to high (scores ranged from 5 to 10). Clinical heterogeneity with regard to trial population and surgical management was reported.

When clamp-crushing was compared with any alternative technique, no significant difference in overall morbidity was found (relative risk 0.89, 95% CI: 0.63, 1.25, six RCTs, n=504 patients). No evidence of significant statistical heterogeneity was found. When stratified by transection technique, clamp-crushing was found to be associated with fewer complications compared with radio-assisted transection (relative risk 0.15, 95% CI: 0.04, 0.62, one RCT, n=50 patients). No other subgroup analysis demonstrated a statistically significant difference in overall morbidity between treatment groups.

No significant differences were found for postoperative biliary leakage, transfusion rates or mortality when clamp-crushing was compared with any alternative technique. Subgroup analysis showed lower transfusion rates with clamp-crushing compared with water-jet dissector (relative risk 0.13, 95 CI: 0.02, 0.93, one RCT). No statistically significant between group differences were found for postoperative biliary leakage, or mortality.

Funnel plots for overall morbidity did not indicate publication bias.

Results demonstrated no benefit of any other technique for hepatic resection compared with clamp-crushing for morbidity, mortality and transfusion rates. Clamp crushing remains the reference technique for transection of the parenchyma in elective hepatic resection.

The review question was supported with clear inclusion criteria in terms of study design and intervention. Several databases were searched without language restriction and some attempts were made to locate unpublished literature. Publication bias was assessed but, given the small number of trials included, this may not been of much value. Methods used to select trials, extract data and assess trial quality were likely to have minimised the possibility of review error and bias. Trial quality was assessed with appropriate criteria and individual trial results reported. Standard statistical methods were used to pool the data and heterogeneity was assessed. The authors' conclusions are overstated, the number of included trials, participants and event rates, as well as reported clinical heterogeneity, limits robust conclusions. Results should be interpreted with caution.

Practice: The authors stated that the clamp-crushing technique can still be recommended for routine use in patients undergoing elective hepatic resection, although in some circumstances (e.g. living donor and complex central liver resections) more accurate tools might be better.

Research: The authors stated that further well-conducted trials are required to evaluate available devices for use in transection of the parenchyma in liver resection such as vascular staplers. Determination of the preferred transection technique in patients with underlying liver disease is also recommended.

Not stated.

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.