CRD summary

This review concluded that the use of mesh in umbilical hernia repair resulted in decreased recurrence and similar wound complications rates compared with tissue repair during open surgery for primary umbilical hernias. Due to the uncertainty about aspects of review process and included study quality, the authors' conclusions should be interpreted with caution.

Authors' objectives

To determine the best surgical approach for the open repair of primary umbilical hernias in adults.

Searching

MEDLINE, EMBASE and the Cochrane Library were searched for relevant English language studies from inception to 2009. Search terms were reported. References were handsearched to identify further relevant studies.

Study selection

Studies were eligible for selection if they were retrospective cohorts, prospective cohorts, case-controls designs or randomised controlled trials (RCTs) that compared mesh to tissue repair of umbilical or paraumbilical hernias. Eligible studies had to report recurrence hernia rates for each group (primary outcome) and have a mean or median follow-up of six months. Mixed studies were not eligible unless they clearly reported separate outcomes for the interventions of interest. The secondary outcome was wound complications.

Within included studies, almost all mesh types were prolene (where reported). Tissue repair types included simple interrupted, Mayo, and Keel.

Two reviewers independently selected studies, but it was not clear how disagreements were resolved.

Assessment of study quality

The quality of RCTs was assessed using methods described in the 2008 Cochrane handbook for systematic reviews of interventions. For non-RCTs, the recommendations of the Cochrane non-Randomised Studies Methods Group (Chi et al 2009) were followed.

The authors did not state how many reviewers performed the validity assessment.

Data extraction

Data required for a meta-analysis were extracted by one reviewer using a standardised form. Where trials used more than one type of primary tissue closure or mesh they were categorised as either one single suture repair or mesh repair group.

Methods of synthesis

Odds ratios (ORs) with 95% confidence intervals (CIs) were pooled using a Mantel-Haenszel fixed-effect model. Statistical heterogeneity was assessed using the Q statistic and considered significant if p<0.10. Heterogeneity was quantified using I^2.

Sensitivity analyses were performed by excluding two studies with significantly different clinical characteristics, and by using the jack-knife method to assess the influence of single studies on reported heterogeneity.

Funnel plots were used to test for publication bias.

Results of the review

Thirteen studies were included in the review (n=1,790 patients; range 42 to 473), including three RCTs (n=292 patients) and ten observational studies. Study quality of the RCTs was judged to be acceptable; study quality of the observational studies was judged to be slightly worse than the RCTs, with unclear reporting. Hernia size appeared to be a confounder. Mean follow-up duration (where reported) ranged from 20 months to 40 months; median follow-up duration (where reported) ranged from 25 months to 54 months.

There were statistically significant pooled effects favouring mesh over suture for hernia recurrence: for RCTs only, the odds ratio was 0.09 (95% CI 0.02 to 0.39; three RCTs; I²=0%; fixed-effect); for cohort studies only, the odds ratio was 0.40 (95% CI 0.21 to 0.75; ten studies; I²=3%; fixed-effect). There was no statistically significant difference between groups for wound complications. Statistical heterogeneity was substantial for wound complications, but not for hernia recurrence.

The jack-knife approach indicated that the statistical heterogeneity in wound complication outcomes was driven by one study. Removing this study from pooled results did not change either of the main outcomes.

Funnel plots did not suggest publication bias.

Authors' conclusions

The use of mesh in umbilical hernia repair resulted in decreased recurrence and similar wound complications rates compared with tissue repair for primary umbilical hernias.

CRD commentary

More than one database was searched, but the search was restricted to English language publications, which increased the risk of language bias. The study selection was clearly reported, and conducted independently by two reviewers, reducing the risk of reviewer error and bias. However, data extraction was only performed by one reviewer, which increased the risk of reviewer error and bias.

Quality assessments were conducted, but the number of reviewers who performed this process was not reported; the quality assessment results were only reported in a limited way. Sufficient primary study details were reported, allowing identification of types of clinical heterogeneity. The results of the research synthesis were adequately reported.

Due to uncertainty about aspects of the review process and study quality, the authors' conclusions should be interpreted with caution.

Implications of the review for practice and research

Practice: The authors stated that mesh should be strongly considered as a means of reducing recurrence in primary umbilical hernia repair. In recurrent cases of such hernias, mesh should be the first choice for repair.

Research: The authors appeared to suggest that further research should be conducted using other clinical outcomes, and to estimate the cost effectiveness of the treatment.

Funding

Not stated.

Bibliographic details

Aslani N, Brown CJ. Does mesh offer an advantage over tissue in the open repair of umbilical hernias? A systematic review and meta-analysis Hernia 2010; 14(5): 455-462. [PubMed: 20635190]

Original Paper URL

http://www.springerlink.com/content/qm515881827v1l78/

Indexing Status

Subject indexing assigned by NLM

MeSH

Hernia, Umbilical /surgery; Humans; Prosthesis Design; Reconstructive Surgical Procedures /methods; Surgical Mesh; Treatment Outcome

AccessionNumber

12010007087

Database entry date

06/07/2011

Record Status

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.