(224e) Novel Polyester-Based Thermoplastic Elastomers for 3D-Printed Personalised Urethra Pessaries

Stress urinary incontinence (SUI) is the most prevalent type of incontinence with up to 46% of women being affected worldwide [1]. One effective means of treatment is the use of a urethra pessary (UP) – a medical device administered and shaped similarly to an intra-vaginal ring (IVR). UPs support the urethrovesical junction and alter the position of the urethra by mechanical stabilisation and therefore prevent involuntary urine loss [2]. The success rate of this type of therapy is highly dependent on a proper pessary fitting, though. Since commercially available UPs are only available in a handful of sizes, their success rate to successfully treat SUI is less than 50% [3]. The present study aims at tackling this shortcoming by presenting personalised UPs processed via material extrusion-based additive manufacturing, also known as fused filament fabrication or 3D-printing, for the first time. A polyester-based thermoplastic elastomer was employed as the raw material, which reveals comparable mechanical properties to the commercially employed silicones, satisfies the necessary regulatory requirements for medical devices as well as exhibits outstanding processability. As methods to assess the mechanical properties of UPs are scarce, the tensile and compression test set-ups commonly employed for IVRs were adapted to accurately capture their critical mechanical properties. By systematically varying the pessaries’ outer (cross-sectional diameter) and inner geometry (infill percentage), a wide range of tensile and compression properties was achieved. All 3D-printed UPs covered a maximum tensile force above a critical female pull force, allowing a flawless pessary removal. Both the maximum compression force at a given deformation, which represents the ability to change the urethra position, and the component compression stiffness, which describes the resistance of the UP to deform under manual compression during pessary insertion, were strongly influenced by the choice of process parameters. Therefore, depending on the severity of SUI, the relevant mechanical properties of the 3D-printed UPs can be customised in a way that they either fall below (for mild cases of SUI), equal or exceed (for severe cases of SUI) those of the commercially available silicone UP with the same outer diameter. Neither an application-relevant long-term immersion into simplified simulated vaginal fluid, nor a long-term static pre-compression emulating the application loading, nor a combination thereof negatively impacted any of the described mechanical parameters. Consequently, the present study confirms the possibility to personalise the geometry as well as the mechanical properties of UPs via 3D-printing a polyester-based thermoplastic elastomer and, hence, to considerably increase the patience adherence and the success rate of UP to successfully and more effectively treat SUI.

1. Reynolds, W.S.; Dmochowski, R.R.; Penson, D.F. Epidemiology of stress urinary incontinence in women. Curr. Urol. Rep. 2011, 12, 370–376.

2. Al-Shaikh, G.; Syed, S.; Osman, S.; Bogis, A.; Al-Badr, A. Pessary use in stress urinary incontinence: a review of advantages, complications, patient satisfaction, and quality of life. Int. J. Womens. Health 2018, 10, 195–201.

3. Jones, K.A.; Harmanli, O. Pessary Use in Pelvic Organ Prolapse and Urinary Incontinence. Rev. Obstet. Gynecol. 2010, 3, 3–9.