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

Correspondence to: Christian D. Fankhauser (e-mail: cdfankhauser@gmail.com)

Division of Urology

Department of Surgery

Cantonal Hospital of Winterthur

Brauerstrass 15

8401

Winterthur

Switzerland

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

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We thank Dr Engel and colleagues for their interest in our systematic review and meta-analysis comparing rectus sheath catheters (RSC) with thoracic epidural analgesia (TEA)1, and we agree that heterogeneity affects both arms of the pooled dataset.

On the intervention side, ‘RSC’ is indeed a broad label. We adopted this umbrella term at the editor’s request, in the knowledge that it summarizes anatomically and technically diverse truncal wall catheter techniques rather than only catheters placed strictly within the rectus sheath. Subgroup analyses by insertion technique would be desirable once sufficient data are available; given the currently limited literature, however, each additional subgroup moves a meta-analysis closer to a collection of small individual studies and erodes the potential of pooling.

On the comparator side, the TEA arms are no less heterogeneous — unavoidably so, in our view, because this heterogeneity reflects real-world practice. The level of insertion is generally determined by external anatomical landmarks with considerable variability, and insertion depth, the final position of the catheter tip, initial bolus and maintenance regimens, local anaesthetic concentration and opioid admixture differ from study to study; virtually every institution follows its own recipe. Declaring some regimens ‘modern TEA’ and others outdated therefore strikes us as arbitrary, and such judgements risk being shaped by the assessor’s prior convictions for or against TEA — even the trial our correspondents present as the contemporary benchmark2 necessarily embodies one institutional recipe among many. These limitations were acknowledged in our discussion and reflect the state of the published literature rather than analytical choices by our group. We accept that a formal GRADE rating and small-study analyses would have strengthened the review further.

We likewise concur that larger trials are needed — ideally stratified by operation, catheter type, insertion depth and anatomical position, and by local anaesthetic agent, concentration, infusion rate, infusion duration and total dose, as well as by the experience of the staff involved, with each stratum adequately powered in its own right. In reality, clinical trials will remain baskets of different techniques and populations, and the same degree of standardization would have to be imposed on TEA across all of the parameters listed above. Such uniformity is unlikely ever to be achieved, and the residual imprecision is a limitation shared by most meta-analyses in this field, our own included.

Finally, we did not proclaim the death of TEA in midline laparotomy, nor did we claim formal equivalence. Rather, the totality of the available evidence suggests that RSC is neither clearly superior nor clearly inferior to TEA with respect to pain outcomes, while being quicker to establish, less resource-intensive and associated with fewer side effects — most notably hypotension (RR 0.40), a finding our correspondents themselves describe as robust and clinically meaningful. Within enhanced recovery pathways, in which early mobilisation and haemodynamic stability are central, these attributes are not trivial. Our report therefore supports continued clinical and scientific interest in RSC, and we join Engel and colleagues in calling for clinical trials with contemporary TEA comparators and pre-specified margins. Genuinely comparable trials will, however, require both techniques to be standardized to a similar degree.

Yours sincerely,

Christian D. Fankhauser, on behalf of all authors