CHAMGAP
APPROVEDReviewed and approved by the Chamgap Editorial Team (2026-08-15). The draft was written by AI, the existence of all 1 cited sources was verified at the original page, and the verdict passed blind grading and adversarial audit. Methodology v0.7.
Verdict No. 2701 · Search date 2026-08-15 · Methodology v0.7

Biological mesh reinforcement,
does it really help with Reduction of clinically detected stoma-site incisional hernia within two years?

30-Second Summary
B
Evidence Grade B · 72 · Safety caution
Biological-mesh reinforcement reduced two-year clinical hernia, but evidence is one trial with substantial missingness
Mesh implantation is surgery with potential infection, seroma, pain, adhesion, and reoperation. ROCSS found no significant increase in wound infection, seroma, or serious adverse events, but surgical candidacy requires specialist assessment.
What the
research shows
The grade is B with 72 points. ROCSS randomized 790 patients; among 650 with the two-year primary assessment, clinical incisional hernia occurred in 39/323 (12%) with mesh versus 64/327 (20%) with sutures alone, adjusted RR 0.62 (95% CI 0.43-0.90). The trial reduced an actual hernia event, but it is the sole confirmatory trial and primary-outcome data were missing for 17.7%.
What the
ads claim
Biological mesh being collagen and its tested effect on clinical hernia are separate facts. The result should not be transferred to another mesh, another placement plane, or treatment of an established hernia.
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Useful facts when choosing a product

  • The tested strategy placed non-crosslinked porcine collagen matrix deep to the abdominal wall with at least 3 cm overlap.
  • ROCSS is one trial dual-registered as NCT02238964 and ISRCTN46330337.
  • The main trial had public funding, while the pilot received Allergan funding and donated mesh.
Gap Measurement · Verdict 2701 · B 72
What advertising claims
What independent, higher-quality research supports
△ GAP
01

What the research actually shows

ROCSS used a computer-based minimization algorithm for 790 patients in 37 hospitals across three countries. Patients and trained outcome assessors were masked. The article states that primary analyses followed the intention-to-treat principle, and the registered two-year clinical hernia endpoint matched the paper. Only 650 patients had the primary assessment, exceeding 15% missingness. NIHR funded the main trial, while Allergan supplied an unrestricted pilot grant and free mesh.

02

Why this is classified as B (72)

A large trial reduced an actual hernia event, but absent independent replication and 17.7% primary-outcome missingness give B with 72 points.

Counterpoint. Symptomatic hernia, reoperation, and long-term durability remain uncertain.

Rejudgment record. Cross-check applied — Cross-checked the ROCSS article and both registrations for the primary endpoint, analysis denominator, masking, funding, and missingness

Scoring profile behind this grade
EndpointHHard endpoint - actual events such as death
ReplicationR1Single confirmatory trial
IndependenceI1Mixed funding sources
Effect sizeE+Meets the clinically important threshold

The scoring table and the verdict agree (B).

Sub-claim grades by effect

This ingredient is marketed for several effects. A single overall grade blends strong and weak claims together, so each effect is graded separately here. The overall grade reflects the strongest disconfirming or core claim.

Effect (sub-claim)GradeBasis
Biological-mesh reinforcement reduces two-year clinical incisional herniaBRates were 39/323 versus 64/327, adjusted RR 0.62.
Biological-mesh reinforcement reduces two-year reoperationDRates were 42/344 versus 54/346, RR 0.78 (0.54-1.13), crossing no effect.

Cross-check — Codex and Claude

This verdict was drafted by Codex through literature review and source-existence checks, cross-checked through blind grading and adversarial audit, and settled by reapplying the methodology boundary rules. Cases with split grades were resolved through rejudgment.
03

Evidence Table

StudyDesignSampleFundingEndpointResultWeight
Reinforcement of Closure of Stoma Site (ROCSS) Collaborative and West Midlands Research Collaborative. 2020 ROCSSPatient- and assessor-masked randomized controlled trial in 37 hospitals across three countries327Public NIHR funding for the main trial; unrestricted pilot grant and donated mesh from AllerganClinically detected stoma-site incisional hernia two years after randomization39/323 (12%) versus 64/327 (20%), adjusted RR 0.62 (95% CI 0.43-0.90), P=0.012Single large confirmatory trial; both registrations identify the same trial
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Receipt — 1 References

All 1 cited sources were verified for existence at the original page (as of 2026-08-15).

Reinforcement of Closure of Stoma Site (ROCSS) Collaborative and West Midlands Research Collaborative. Prophylactic biological mesh reinforcement versus standard closure of stoma site (ROCSS): a multicentre, randomised controlled trial. Lancet. 2020;395:417-426. PMID: 32035551. DOI: 10.1016/S0140-6736(19)32637-6. NCT02238964; ISRCTN46330337.
checked
Draft and rewrite: Codex (AI) · Verification: Codex blind grading and adversarial audit · Final adjudication: Claude
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-08-15 · Corrections: none

Cite this verdict

Biological mesh reinforcement x prevention of incisional hernia after stoma closure Evidence Grade B card
[Chamgap] Biological mesh reinforcement x prevention of incisional hernia after stoma closure — Evidence Grade B·72. 1 cited sources checked. Source: https://chamgap.com/en/verdicts/gut/biological-mesh-stoma-closure-incisional-hernia/ · CC BY 4.0

CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.

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What this document does and does not do

Chamgap is an information source. It reports what research has and has not confirmed; it does not tell readers what to take or buy. That decision belongs to readers and, when needed, medical or legal professionals. This verdict reflects literature available up to the search date and may change as new research appears. Nothing here is medical advice.