Vaginal Orthosis Post Native Tissue Reconstructive Surgery: Design and Phase 0

Objectives: Pelvic organ prolapse (POP) recurrence following native tissue repair occurs with composite failure rates of 9%-19% within 12 months, predominantly involving the apical/anterior compartments. Although risk factors such as an enlarged levator hiatus area have been identified, there are currently no intra- or postoperative interventions to reduce POP recurrence rates. Previous studies note a pressure differential across the levator hiatus contributing to development of POP. A vaginal pessary may mitigate unopposed intra-abdominal pressure on actively healing vaginal tissue, but existing pessaries are not configured for post-surgical anatomy. We hypothesized that a postoperative vaginal orthosis, designed to support the vaginal apex and anterior vagina counteracting this pressure differential, may improve wound healing in a manner similar to supportive orthoses used after orthopedic procedures. The objective was to develop a novel vaginal orthosis (NVO) device prototype through an iterative design process based on investigator and user feedback.

Methods: The design and refinement of the NVO within a larger ongoing study evaluating post-operative outcomes in patients undergoing native tissue repair and the use of an NVO are presented. The NVO was designed based on pelvic floor biomechanical principles to mitigate unopposed intrabdominal pressure on the anterior vaginal wall by absorbing and redirecting intraabdominal forces to the levator ani. The device was tailored to accommodate postoperative vaginal caliber and axis. Prototypes were fabricated by 3D-printing negative molds, cast, and cured with medical-grade biocompatible silicone. After IRB approval, ten healthy volunteers were recruited for a two-day trial to provide qualitative feedback for iterative design refinement (Phase 0).

Results: Through an iterative engineering design process, initial concepts, such as a cylindrical shape aligned with the vaginal axis, were refined to align with the natural, resting H-shape of the vagina, resulting in a flat configuration. Key features for this concept included the distal self-retaining feature, posterior curvature, proximal taper, and apical and anterior contact areas for vaginal support (Figure 1). A more rigid material to withstand intraabdominal forces without folding was required, therefore was manufactured with Shore A60 (medium soft) instead of A40 (soft) silicone. Characteristics of volunteers for Phase 0 during active use and removal are in Table 1. Based on participant feedback, the NVO retaining feature width range was reduced (47.5-63 mm to 45-50 mm) to decrease pressure on lateral vaginal walls and levator ani distally maintaining self-retaining function. Updates were also made to the fitting and education process providing increased descriptive instructions for insertion and removal.

Conclusions: A novel vaginal orthosis was designed specifically tailored to facilitate wound healing using an orthopedic model, improving the design through iterative feedback. The Phase 1 study to evaluate the safety and feasibility of the NVO in post-operative participants is underway to be followed by a pilot RCT.