Remodeling and Retention of Vaginal Canal Length via Sleeve Implantation: A Preclinical Study

Background/Objectives: Vaginal atresia, most commonly caused by Müllerian agenesis, is treated with vaginal dilation therapy or surgical vaginoplasty; however, dilation therapy requires prolonged patient adherence. In a previous study, a single, statically implanted vaginal expansion sleeve (VES) produced significant lengthening of vaginal tissue. This study evaluated whether progressive serial VES expansion increases vaginal canal length and whether the length gained is retained after device removal. Methods: Baseline vaginal canal length was measured in four intact (non-ovariectomized) Sprague-Dawley rats. A VES, a spring-like woven cylinder, was custom-fabricated at 1.3 times the vaginal canal length, implanted for one week, and then replaced with a larger device; this was repeated weekly for three weeks. After serial expansion, animals recovered for two weeks before final measurements. Changes in length over time were analyzed using repeated-measures ANOVA, and vaginal tissue was harvested for histologic analysis. Results: Mean vaginal canal length increased from 24.50 ± 0.58 mm at baseline to 37.25 ± 2.87 mm at Week 3, a 52% increase (n = 4; p < 0.0001 for change over time). Two weeks after VES removal, the mean length was 35.50 ± 0.58 mm, 11.0 mm above baseline, indicating retention of approximately 86% of the length gained. Histologic examination showed impaired squamous maturation or regenerative changes, mixed inflammation, muscularis disruption, and interspersed subepithelial fibrosis. Conclusions: Serial VES expansion produced significant vaginal lengthening that was largely maintained after device removal. The histologic findings indicate a tissue response to sustained mechanical expansion, the long-term significance of which remains unknown. Serial VES-mediated distraction vaginogenesis warrants further study.