Functional Magnetic Stimulation for Post-Prostatectomy Urinary Incontinence: A Retrospective Cohort Study of Real-World Outcomes and Factors Associated with Treatment Response

Introduction: Post-prostatectomy urinary incontinence represents a major determinant of postoperative quality of life. Functional magnetic stimulation (FMS) is a non-invasive pelvic floor rehabilitation modality used in the conservative management of post-prostatectomy urinary incontinence; however, rehabilitation-related factors influencing treatment response remain insufficiently defined. The objective of this study was to evaluate real-world outcomes after an FMS protocol and to identify clinical and therapeutic factors associated with an investigator-defined exploratory response. Materials and Methods: This retrospective, single-center cohort study included 67 men treated with functional magnetic stimulation for urinary incontinence after radical prostatectomy. The primary endpoint was the post-FMS response score, assessed using an investigator-defined, non-validated 0–5 ordinal clinical response scale. Clinical, oncological, surgical, and rehabilitation-related variables were analyzed. Associations with treatment response were evaluated using univariable analyses and primary multivariable ordinal logistic regression. Results: A total of 67 patients were included, with a median age of 67 years [IQR: 63–70], a median PSA of 9.0 ng/mL [IQR: 6.45–14.08], a median number of FMS sessions of 11 [IQR: 8–13], and a median time from prostatectomy to first FMS session of 48 days [IQR: 30–83]. Any improvement was observed in 56 patients (83.6%), while investigator-defined exploratory response threshold was achieved in 28 patients (41.8%) and good/excellent response in 21 patients (31.3%). Patients aged ≤65 years had higher response scores than those aged >65 years (3 [IQR: 2–4] vs. 2 [IQR: 0.75–3], p = 0.025). Timing of FMS initiation was not associated with response when analyzed as a continuous variable. No statistically significant associations were detected between post-FMS response scores and PSA, ISUP grade group, EAU risk classification, or surgical approach in this cohort; however, clinically relevant associations cannot be excluded given the modest sample size. In the primary multivariable ordinal logistic regression model, older age was independently associated within the fitted model with lower odds of achieving a higher post-FMS response category (OR = 0.927, 95% CI: 0.859–0.999, p = 0.048), while the number of completed FMS sessions was independently associated within the fitted model with higher odds of achieving a higher response category (OR = 1.093, 95% CI: 1.009–1.184, p = 0.029). FMS initiation after 120 days was not independently associated with response category (OR = 0.447, 95% CI: 0.096–2.081, p = 0.305). Conclusions: Subjective functional improvement was observed after FMS in this retrospective outcome-evaluable cohort; however, because standardized baseline continence severity and a comparator group were unavailable, treatment efficacy cannot be established. Younger age and a greater number of completed FMS sessions were associated with higher post-FMS response categories in the exploratory multivariable analysis. However, the association with session number should not be interpreted as evidence of a causal dose–response relationship. Timing of FMS initiation was not associated with response when analyzed continuously. Exploratory 120-day and 180-day threshold analyses produced nominal subgroup differences but should be considered potentially data-dependent and hypothesis-generating only.