Evaluation of Parameters Determining the Pull-Out Strength of Poly(L-Lactide-Co-ϵ-Caprolactone) Barbed Suspension Threads: A Comparative ex vivo Study

Salvatore Fundaro,1 Dennis Malvin Hernandez Malgapo,2,3 Martina Manni4 1Cosmetic Surgery, Qute Clinic, Modena, Italy; 2Regenerative Medicine, EW Villa Medica Manila Premiere Center, Pasay City, Metro Manila, Philippines; 3Preventive Medicine, St. Luke’s College of Medicine, Metro Manila, Philippines; 4Scientific Affairs, RELIFE S.r.l., Florence, ItalyCorrespondence: Dennis Malvin Hernandez Malgapo, Regenerative Medicine, EW Villa Medica Manila Premiere Center, Pasay City, Metro Manila, Philippines, Tel +639286745699, Email [email protected]: This study aimed to examine a pull-out strength test methodology and compare the pull-out strength of different insertion methods for poly(L-lactide-co-ϵ-caprolactone) (PLCL) barbed suspension threads.Methods: A custom-designed “pull-out strength test device” was used to measure the maximum force required to pull out threads inserted into an ex vivo turkey breast model.Results: Insertion techniques influence pull-out strength. Additionally, trend analysis indicated that thinner needles (0.85 mm) generally yielded higher pull-out resistance than larger diameter needles (1.28 mm), suggesting they may create a tighter initial grip within the tissue.Conclusion: Different insertion techniques influence the pull-out strength of PLCL in an ex vivo model.Plain Language Summary: Why was this study done?Barbed threads are used to lift sagging facial tissue without surgery. However, doctors lack standardized data on which insertion methods provide the strongest, most secure hold. This study aimed to find out which techniques grip the tissue best.What did the researchers do and find?Using a custom testing device and an animal tissue model (turkey breast), researchers measured the force needed to pull out specific absorbable threads (PLCL). They tested various clinical insertion methods. They found that the insertion technique greatly impacts the thread’s holding strength. Angled patterns, like the “J-stitch”, and self-locking thread systems provided a much stronger grip than straight-line insertions. The length of the thread’s barbed section did not significantly change its holding power. Additionally, a trend indicated that threads inserted with thinner needles tended to hold more tightly in the tissue.What do these results mean?Because this study was performed on animal tissue, the results cannot directly predict human clinical outcomes. However, the findings strongly suggest that the specific technique a doctor uses is a critical factor in how well a thread anchors. Utilizing angled insertion patterns and thinner needles may improve the thread’s overall stability. This study also provides a reliable, standardized testing method for researchers to evaluate future thread designs.Keywords: suspension suture, noninvasive face lifting, insertion technique, poly(L-lactide-co-ϵ-caprolactone)