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Open Preperitoneal Techniques versus Lichtenstein Repair for elective Inguinal Hernias.

BACKGROUND
Current techniques for inguinal hernia repair show similar recurrence rates. Therefore, recurrence is no longer the main issue discussed when considering improving the current standards for groin hernia repair. Post surgical chronic pain represents a major, largely unrecognised clinical problem. Consequently, there is a need to not only decrease an extensive dissection in the inguinal canal with less manipulation of the inguinal nerves, but also to minimize the interaction between the mesh and major surrounding structures. As a result, placing the mesh in the preperitoneal space is a valuable option.


OBJECTIVES
To compare elective open preperitoneal mesh techniques with Lichtenstein mesh repair in terms of pain.


SEARCH METHODS
We searched The Cochrane Central Register of Controlled Trials (The Cochrane library 2011, Issue 4), MEDLINE (January 1966 to April 2011), EMBASE (1947 to October 2009), and ISI WEB OF KNOWLEDGE (1900 to April 2011) for randomized controlled trials. The reference list of identified trials, the World Journal of Hernia and Abdominal Wall Surgery, and relevant book chapters were handsearched for useful trials. If we found relevant ongoing trials using national and international trials registers, we contacted the main investigators for further information. The language of the trials was not an exclusion criterion. 


SELECTION CRITERIA
Randomized controlled studies comparing elective open preperitoneal mesh techniques with Lichtenstein mesh repair.


DATA COLLECTION AND ANALYSIS
Three authors independently extracted the pre-specified data and assessed the methodological quality using domain-based evaluation. Missing information was obtained by contacting the original investigators using open-ended questions.


MAIN RESULTS
Three eligible trials involving 569 patients were identified. Due to methodological limitations in the included studies, there was considerable variation in the results of acute (risk range 38.67% to 96.51%) and chronic pain (risk range 7.83% to 40.47%) across the control groups. Therefore, meta-analysis was not performed but the results of the outcomes in the individual trials were compared. Two trials involving 322 patients reported less chronic pain after preperitoneal repair (relative risk (RR) 0.18, number needed to treat (NNT) 8; RR 0.51, NNT 5), whereas one trial, including 247 patients, described more chronic pain after this repair (RR 1.17, NNT 77). The same trials favoured the preperitoneal technique concerning acute pain (RR 0.17, NNT 3; RR 0.78, NNT 7), whereas in the third trial it was almost omnipresent and thus comparable in both intervention arms (RR 0.997, NNT 333). Early and late hernia recurrence rates were similar across the studies, whereas contrasting results were reported for other early outcomes as infection and hematoma. No late mesh infection occurred in the included trials. 


AUTHORS' CONCLUSIONS
Both techniques are valid as they result in similar low recurrence rates. Evaluation of pain results in the individual trials shows some evidence that preperitoneal repair causes less or comparable acute and chronic pain compared to the Lichtenstein procedure. We emphasize the need for homogeneous high quality randomized trials comparing elective preperitoneal inguinal hernia techniques and Lichtenstein repair in terms of chronic pain.