Degradation of polypropylene<i>in vivo</i>: A microscopic analysis of meshes explanted from patients
Bibliographic record
Abstract
Polypropylene meshes, originally introduced for hernia repair, are presently utilized in several anatomical sites. Several million are implanted annually worldwide. Depending on the device, up to 10% will be excised to treat complications. The excised meshes can provide material to study the complications, however, they have remained underutilized over the last decades and the mechanisms of complications continue to be incompletely understood. The fundamental question as to whether polypropylene degrades in vivo is still debated. We have examined 164 excised meshes using conventional microscopy to search for features of polypropylene degradation. Four specimens were also examined by transmission electron microscopy. The degraded material, detected by its ability to absorb dyes in the degradation nanopores, formed a continuous layer at the surface of the mesh fibers. It retained birefringence, inclusions of non-degraded polypropylene, and showed ability to meld with the non-degraded fiber core when heated by the surgical cautery. Several features indicated that the degradation layer formed in vivo: inflammatory cells trapped within fissures, melting caused by cautery of excision surgery, and gradual but progressive growth of the degradation layer while in the body. Cracking of the degraded material indicated a contribution to clinically important mesh stiffening and deformation. Chemical products of degradation need to be analyzed and studied for their role in the mesh-body interactions. The described methods can also be used to study degradation of other materials. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 237-248, 2017.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".