EVALUATION OF THE SHORT TERM HOST RESPONSE AND BIOMECHANICS OF AN
ABSORBABLE POLY-4-HYDROXYBUTYRATE SCAFFOLD IN A SHEEP MODEL FOLLOWING
VAGINAL IMPLANTATION
Abstract
Objective: To compare the host and biomechanical response to a fully
absorbable poly-4-hydroxybutyrate (P4HB) scaffold to the response to PP
mesh in an animal model of vaginal POP surgery. Design: A study
employing a sheep model Setting: KU Leuven Center for Surgical
Technologies Population: 14 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
protocol. Main outcome measures: Gross necropsy, histological and
biomechanical evaluation of explants, and the in vivo P4HB scaffold
degradation were evaluated at 60- and 180-days post-implantation.
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 (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 SEM, 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, a clinical study for vaginal POP surgery may be warranted to
demonstrate efficacy. Key words: Pelvic organ prolapse, vaginal surgery,
Poly-4-hydroxybutyrate, degradable scaffold, host response,
biomechanics.