The Efficacy of Minimally Invasive Implantable Wireless Electrical Stimulation for the Treatment of Stress Urinary Incontinence in a Rat Model

초록

Purpose: Current therapies using midurethral sling mesh to treat stress urinary incontinence (SUI) are often considered in-sufficient. This study aims to evaluate the therapeutic efficacies of a minimally invasive implantable wireless electrical stimula-tor as an alternative treatment of SUI.<br /> Methods: SUI was induced in 12 female, 12-week-old Sprague-Dawley rats with a deteriorated urethral sphincter complex by mechanical dilatation of the vagina. Six rats underwent sham operations. Four weeks after inducing SUI, 12 rats with SUI were divided into 2 groups. One group received a transplantation of an implantable wireless electrical stimulator, and the other midlite incision and suturing. A total of 4 electrical stimulations were applied for 30 minutes twice weekly for 4 weeks in im-plantation model. Cystometric parameters including leak point pressure, urethral pressure and electromyography, histological examinations, immunostaining for Masson trichrome stain were measured at 4 weeks after intervention.<br /> Results: After SUI induction, mean leak point pressure (LPP) was significantly lower in SUI groups than in controls (25.0 +/- 6.9 cm H:O vs. 62.6 +/- 4.1 cm H2O, P = 0.012 ). At 4-week postintervention, the +ES group (SUI rat model with stimulation) dem-onstrated significantly higher LPP than the-ES group (48.8 +/- 8.4 cm H2O vs. 26.0 +/- 6.6 cm H2O, P = 0.002 ) Urethral pressure showyd a nonsignificant upward trend in the +ES group (SUI rat model without stimulation) compared with-ES (20.5 +/- 1.4 cm HrO vs. 18.1 +/- 1.1 cm H:O, P = 0.07 ) Histology showed improved tissue organization with reduced inflammatory infiltra-tion, and Masson staining demonstrated a trend toward higher collagen density in +ES (bladder: 28.3% +/- 5.2% vs. 32.5%+/- 7.6%, P = 0.292 urethra: 44.2% +/- 8.6% vs. 51.7% +/- 8.2%, P = 0.153 )<br /> Conclusions: These results indicate that an implantation of a wireless electrical stimulator can help to improve urethral sphintter function in SUI rat model. Moreover, the minimally invasive wireless electrical strategy may represent a promising therapeutic modality for pelvic floor muscle rehabilitation in the treatment of SUI with potential for clinical translation.

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