THE USE OF POLYDIOXANONE THREADS COMBINED WITH HYALURONIC ACID FILLERS - LITERATURE REVIEW –
Authors: Marques Ana Moreira 
Published: December 2024

This study focuses on both the individual understanding of how polydioxanone threads and hyaluronic acid fillers work, plus the combined used of both techniques to improve the anti-aging treatment and deliver the best possible results to our patients. The combination of treatments is, in most cases, the best approach to reduce signs of aging, improve skin quality and fix asymmetries and face proportions.

However, the combination of treatments should be well studied and planned so that the single procedures result in a balanced and efficient harmonization.

The aim is to get together information which reinforces the hypothesis that PDO threads are more easily degraded when applied together with hyaluronic acid fillers.

Methods: This study is a literature review. It is important to use planning skills, money resources and scientific knowledge to take maximal advantage of the options we have available in aesthetic medicine and get the best outcome. With that purpose, a detailed literature search about the topic was done in Pubmed. Several articles were used to elaborate this study, including case reports and laboratory in vitro experiments.

Results: Polydioxanone is a homopolymer of paradioxanone, biodegradable by hydrolysis, since in contact with watery substances, its ester chains are broken and low molecular weight chain segments diffuse, which leads to its heterogenous biodegradation by layers, from the periphery to the center. Hyaluronic acid is a biocompatible and widely available polysaccharide from the glycosaminoglycan family. It is a hydrophilic polymer and so, it improves water retention. In vitro experiments have shown that hyaluronic acid, induces rapid biodegradation of PDO threads by hydrolysis, starting already 24h after the contact with polydioxanone, leading to an increase in the fibers’ interlaminar and intrafibrillar space, with those empty spaces corresponding to zones of hydrolysis. At 48h, these spaces increase as the dissolution of the peripheral and central layers occurs. After 72h, empty spaces in the central layer and a frayed pattern on the periphery of the thread are seen, with disorganization of fibrils, breakage of molecules and loss of mass. The degradation happens from the periphery to the center, causing small cracks and allowing water to diffuse into the center. A case report of a woman with complications post PDO thread implantation, in which hyaluronic acid was injected in 3 occasions (0,5mL each time) as a way to try to speed up the process of polydioxanone degradation and accelerate the treatment of these complications, showed that after 21 days, the patient showed improvements, with reduction of oedema and at 45 days there were visibly less skin folds and irregularities caused by the thread.

Conclusions: The stipulated hypothesis that hyaluronic acid increases the speed of degradation of PDO threads is correct. As such, both products shouldn’t be used simultaneously, not because complications will develop, but because it is not an efficient, result friendly choice, since PDO threads’ durability will significatively decrease. Contrarily, in cases in which PDO thread implantation lead to complications, injecting of hyaluronic acid could be an option to accelerate the treatment of those complications, as an alternative to surgical intervention.