Evaluation of the short-term host response and biomechanics of an absorbable poly-4-hydroxybutyrate scaffold in a sheep model following vaginal implantation.

OBJECTIVE

To evaluate the host- and biomechanical response to a fully absorbable poly-4-hydroxybutyrate (P4HB) scaffold in comparison with the response to polypropylene (PP) mesh.

DESIGN

In vivo animal experiment.

SETTING

KU Leuven Center for Surgical Technologies.

POPULATION: Fourteen parous female Mule sheep.

METHODS

P4HB scaffolds were surgically implanted in the posterior vaginal wall of sheep. The comparative PP mesh data were obtained from an identical study protocol performed previously.

MAIN OUTCOME MEASURES: Gross necropsy, host response and biomechanical evaluation of explants, and the in vivo P4HB scaffold degradation were evaluated at 60- and 180-days post-implantation. Data are reported as mean ± standard deviation (SD) or standard error of the mean (SEM).

RESULTS

Gross necropsy revealed no implant-related adverse events using P4HB scaffolds. The tensile stiffness of the P4HB explants increased at 180-days (12.498 ± 2.66 N/mm SEM [p =0.019]) as compared to 60-days (4.585 ± 1.57 N/mm) post-implantation, while P4HB degraded gradually. P4HB scaffolds exhibited excellent tissue integration with dense connective tissue and a moderate initial host response. P4HB scaffolds induced a significantly higher M2/M1 ratio (1.70 ± 0.67 SD, score 0-4), as compared to PP mesh(0.99 ± 0.78 SD, score 0-4) at 180-days.

CONCLUSIONS

P4HB scaffold facilitated a gradual load transfer to vaginal tissue over time. The fully absorbable P4HB scaffold, in comparison to PP mesh, has a favorable host response with comparable load-bearing capacity. If these results are also observed at longer follow-up in-vivo, a clinical study using P4HB for vaginal POP surgery may be warranted to demonstrate efficacy.

TWEETABLE ABSTRACT: Degradable vaginal P4HB implant might be a solution for treatment of POP.