How we appraise
Every source is read in full where the full text can be obtained, critically appraised with the instrument its design calls for, and filed under each wound type it bears on. Sources that do not support NPWT are kept and shown: an evidence library is most useful where it says what the evidence does not show.
Three different ratings
A card or a page can carry up to three ratings. They answer different questions and are never interchangeable.
| Rating | Question it answers | Scale |
|---|---|---|
| GRADE ⊕⊕⊕◯ Moderate | Evidence certainty. How sure can we be of this study's effect estimate? | GRADE: High ⊕⊕⊕⊕, Moderate ⊕⊕⊕◯, Low ⊕⊕◯◯, Very low ⊕◯◯◯. Where GRADE cannot apply, the OCEBM level of evidence or CERQual confidence is shown instead, or "Not graded" with the reason. |
| Guideline quality 4/7 | Guideline quality. How well was this guideline or consensus developed? | AGREE II overall score out of 7, from this library's own appraisal. |
| SA evidence position: Moderate SA evidence position: Guarded | South African context. Does South African guidance endorse NPWT for this wound type, and does the evidence bear it out? | Moderate only where WHASA 2021 endorses the wound type and at least one non-retracted source supports NPWT for it at GRADE High or Moderate certainty. Otherwise Guarded. It is this library's synthesis, not an official guideline and not a GRADE rating. It can never rise above Moderate, because WHASA 2021 itself scores 4/7 on AGREE II (rigour of development 23%). Dr Weir may hold a wound type at Guarded on clinical grounds even where it would qualify. |
Other labels on a card
| Study type | The design: randomised trial, systematic review, cohort, case series, guideline, and so on. |
| Direction | Supports NPWT, Challenges NPWT or Context (background, mechanism, comparator or cost). Not NPWT evidence marks a source with no negative pressure in it, held only to describe the comparator, the baseline infection rate or the cost an NPWT argument is measured against. |
| Figures | A separate check that the numbers quoted on the card appear in the source. It says nothing about the quality of the study: a paper can have its figures checked and still be GRADE Very low. Figures checked: a person compared the numbers with the full text. (auto): an automated screen found them in the source PDF. Abstract only: appraised from the abstract; the full text has not been obtained. Figures unconfirmed or Flagged: not confirmed against a full text. Figures don't reconcile: the full text was read and the paper's own numbers contradict each other. |
| Year | The year of first publication (online-first where applicable); the full reference gives the issue year. |
| Reviewed | The date the appraisal was last reviewed. |
How a source is handled
Source identified → full text obtained → study design classified → critically appraised → numbers extracted and checked against the source → retraction status checked in PubMed → filed under each relevant wound type → cited on the wound-type page if it adds credible evidence.
Manufacturer-sponsored material is labelled as such and ranked lowest. Papers that are flagged, retracted or contain no data are listed but never counted as evidence.
Retracted papers
Listed so they can be recognised; excluded from every count and hidden in the evidence lists unless "Show retracted papers" is ticked.
- Yuan S, Zhang T, Zhang D, He Q, Du M, Zeng F. [RETRACTED] Impact of negative pressure wound treatment on incidence of surgical site infection in varied orthopedic surgeries: a systematic review and meta-analysis. Int Wound J. 2023;20(6):2334-2345 (RETRACTED 2025 — retraction notice Int Wound J 2025;22(4):e70561, doi 10.1111/iwj.70561, PMID 40251145)
- Wang Z, Feng C, Wang XJ. [RETRACTED] Negative pressure wound therapy for patients with mediastinitis: a meta-analysis. Int Wound J. 2020;17(6):2019-2025 (RETRACTED April 2025 — retraction notice Int Wound J 2025;22(4):e70646, doi 10.1111/iwj.70646, PMID 40265215, PMC12015185. No funding statement and no conflict-of-interest statement appear in the original article.)
- Ali Z, Anjum A, Khurshid L, Ahad H, Maajid S, Dhar SA. [RETRACTED] Evaluation of low-cost custom made VAC therapy compared with conventional wound dressings in the treatment of non-healing lower limb ulcers in lower socio-economic group patients of Kashmir valley. J Orthop Surg Res. 2015;10:183 (RETRACTED 2017 — retraction notice J Orthop Surg Res 2017;12(1):62, doi 10.1186/s13018-017-0558-3, PMID 28427404, PMCID PMC5397907)
Changes
- 4 October 2026. The library moved from one long page to separate pages for each wound type, with the evidence in one minute, plain-language filters and downloadable reference lists. The "RSA clinical position" badge was renamed the South African evidence position; its rule is unchanged.
- 27 September 2026. The South African position badge follows one stated rule, set out above.
- 15 September 2026. Eight wound types previously marked "strong" on the strength of WHASA 2021 were reduced to Moderate, because this library appraises WHASA 2021 at AGREE II 4/7 (rigour of development 23%, editorial independence 25%). No evidence rating on any source changed.
About this library
Maintained by Dr Gregory Weir, vascular surgeon, Pretoria. Appraisals are prepared with the assistance of Anthropic's Claude and published under Dr Weir's editorial responsibility.
Funding and conflicts of interest: the library receives no external or industry funding. Dr Weir declares no conflicts of interest with NPWT manufacturers.
Corrections and suggestions are welcome: please email [email protected].