Background: Continuous peripheral nerve blocks (CPNBs) have been investigated to control pain for abdominal surgery via midline laparotomy while avoiding the adverse events of opioid or epidural analgesia. The review compiles the evidence comparing CPNBs to multimodal and epidural analgesia. Methods: We conducted a systematic review using broad search terms in Medline, EMBASE, Cochrane. Primary outcomes were pain scores and cumulative opioid consumption at 48 hours. Secondary outcomes were length of stay and postoperative nausea and vomiting (PONV). We rated the quality of the evidence using Cochrane and GRADE recommendations. The results were synthesized by metaanalysis using Revman. Results: Our final selection included 26 studies (1,646 patients). There was no statistically significant difference in pain control comparing CPNBs to either multimodal or epidural analgesia (low quality evidence). Less opioids were consumed when receiving epidural analgesia than CPNBs (mean difference (MD)-16.13 [95% CI-32.36,-0.10], low quality evidence) and less when receiving CPNBs than multimodal analgesia (MD-31.52 [95% CI-42.81,-20.22], low quality evidence). The length of hospital stay was shorter when receiving epidural analgesia than CPNBs (MD-0.78 days [95% CI-1.29,-0.27], low quality evidence) and shorter when receiving CPNBs than multimodal analgesia (MD-1.41 days [95% CI-2.45,-0.36], low quality evidence). There was no statistically significant difference in PONV comparing CPNBs to multimodal (high quality evidence) or epidural analgesia (moderate quality evidence).

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I shall not today attempt further to define the kinds of material I understand to be embraced within that shorthand description and perhaps I could never succeed in intelligibly doing so. But I know it when I see it.'dUS Supreme Court Justice Potter Stewart 1964.