Comment on: Rectus sheath catheters versus thoracic epidural analgesia for pain management after open surgery — a systematic review and meta-analysis

Correspondence to: Dominque Engle (email: dominique.engel@insel.ch)

Department of Anaesthesia and Pain Medicine

University Hospital Bern

Inselspital

Switzerland

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BJS, https://doi.org/10.1093/bjs/znag058, published 13 May 2026

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Fankhauser and colleagues¹ provide the broadest synthesis to date comparing rectus sheath catheters (RSC) with thoracic epidural analgesia (TEA). The Discussion candidly acknowledges that "absence of evidence is not evidence of absence" — a humility that does not entirely survive into the Abstract Conclusion. Two structural features of the pooled dataset warrant emphasis.

First, the "RSC" label is generous: continuous preperitoneal infusions, transversus abdominis plane catheters, wound catheters at variable anatomical depths, and ON-Q catheters following thoracotomy are pooled as a single intervention.

Second, and more consequentially, the TEA comparator is heterogeneous — ranging from contemporary continuous bupivacaine plus fentanyl² to intermittent epidural morphine without local anaesthetic³. Structurally weaker TEA arms cluster on the RSC-favouring tail of the pain distribution and pull the lower confidence bound towards equivalence. By contrast, the single included trial combining pre-registration, ERP standardization, modern TEA, and stratified randomization in midline laparotomy² reported significantly lower dynamic pain at its pre-defined 24-hour primary endpoint with TEA (median 33 versus 50.5; P = 0.018) — even after the RSC arm had been augmented with intravenous morphine and a fentanyl patch to compensate for absent visceral coverage⁴. This sits uncomfortably with an equivalence narrative.

A pre-specified sensitivity analysis restricted to trials using contemporary LA-plus-opioid TEA in midline laparotomy would narrow this interval considerably. The absence of a GRADE rating or formal small-study analysis is a further limitation.

The reduction in hypotension (RR 0.40) remains robust and clinically meaningful. Beyond that, reports of the death of TEA in midline laparotomy are, to borrow a phrase, greatly exaggerated. Non-inferiority trials with contemporary comparators and a pre-specified non-inferiority margin are needed.