Many treatments of SUI were developed to ensure patients’ quality of life. Different treatments approached to improve the clinical symptoms of SUI from their perspectives, such as pelvic floor muscle training (PFMT), vaginal pessaries, surgical treatments (mid-urethral sling, Burch urethropexy, pubovaginal sling, artificial urethral sphincter) [29, 30] or medical treatments (duloxetine) [31–33]. Nevertheless, most of these treatments focused on maintaining or strengthening the support of the pelvic floor and vaginal connective tissue. MS is one of the options similar to HIFEM. Yamanishi et al., 2019 investigated the urinary-related parameter of MS in SUI patients. Their results showed that ICIQ-SF score, QOL score, and ALPP significantly improved after the MS treatment in the 2.5-month follow-up [34]. Our result revealed the effect of HIFEM on the ICIQ-SF questionnaire, and it showed a noticeable improvement in both 1-month and 6-month follow-ups (Table 3). HIFEM is a technology based on electromagnetic stimulation. Some previous research also used electrical muscle stimulation (EMS), which is often compared to HIFEM.
EMS was first used as a therapy that could be traced back to 1745 when a German physician, Altus Kratzstein, found that electrical currents could control muscle. In the early stage, EMS was mainly used to treat motor paralysis patients [35]. It could stimulate involuntary contraction via different electrical current forms and frequencies [36]. Compared to HIFEM, EMS worked mainly on the surface and needed to contact the skin directly. Besides, the FDA depicted that some unregulated EMS devices reported severe side effects such as shocks, burns, bruising, skin irritation, pain, and interference with other medical devices [37]. Even with different mechanisms of HIFEM and EMS, some researchers still compared them to the effect of muscle training [38–40].
Alazab et al., 2022 compared the effect of EMS and HIFEM on stroke-induced shoulder subluxation. Their data showed that all groups showed significant improvement in the functional ability of the upper extremities to pre-treatment. Moreover, the HIFEM group showed the best efficacy in these three groups. HIFEM, EMS group also demonstrated an apparent increase in the supraspinatus and deltoid muscle contraction amplitude. HIFEM treatment showed better efficacy in this study than EMS treatment [40]. Previous studies have already compared the effect of HIFEM and EMS on pelvic muscle and UI. Silantyeva et al., 2021 used 3D ultrasounds to assess anteroposterior diameter, lateral-lateral diameter, and hiatal area. The result was that only the HIFEM group showed significant differences from the control group, and HIFEM also demonstrated a better efficacy on pelvic floor disability than the EMS group. Besides, fewer patients were found with urine leakage in the HIFEM group [39]. Recently, more research focused on the effect of HIFEM on SUI in different aspects.
Samuels et al., 2019 demonstrated that almost 80% of their patients significantly improved from six times the treatment of HIFEM. They also evaluated their patients in ICIQ-SF score and pad test at 3-month follow-up. The ICIQ-SF score significantly decreased from 10.57 ± 4.22 to 4.16 ± 4.04 (64.42%), and the pad test significantly reduced from 2.47 ± 2.25 to 1.19 ± 1.91 (53.68%) at 3-month follow-up. Interestingly, they recorded data after the six treatments (3 weeks). The result showed that both tests remained in a relatively low value even though no treatment was performed after three weeks. Moreover, a pronounced decrease in urine leakage was reported [15]. Our study showed a similar trend as Samuels et al., 2019 but in a more extended observation period.
Braga et al., 2022 showed that 3-tesla electromagnetic devices were treated 16 times. They found that 47% of patients significantly improved in 2-month follow-up. The HIFEM treatment also changed the score of UDI-6-SF, IIQ-7, and ICIQ-SF questionnaires [41]. We also performed UDI-6, IIQ-7, and ICI-Q SF. The data in our study also showed a similar trend: ICIQ-SF showed a substantial reduction, and IIQ-7 had a more minor reduction.
Then, Doğanay et al., 2010 demonstrated a one-year follow-up in their study. They evaluated magnetic-field stimulation in SUI and UUI. They measured pad test, voiding diary, Visual Analogue score (VAS), and urodynamic parameters. Their data showed that voiding, VAS score, and pad test significantly reduced after the HIFEM treatment in one-year follow-up. However, bladder capacity (Vfst), maximum cystometric capacity (MCC), and Valsalva leak point pressure (VLPP) did not change [42]. In our 6-month follow-up, Qmax, RU, DO, Vfst, MCC, Pdet at Qmax, and FUL did not show noticeable change after the HIFEM treatment, similar to the one-year follow-up study. Only MUCP and UCA significantly increased (Table 4).
Our study served as a pioneer in utilizing ultrasonography to examine the effect of HIFEM technology on urethral topography. The data showed no significant change in all parameters, including bladder mobility, urethral area in the rest, and stress. Compared to our previous research, we suggested that the HIFEM treatment did not produce noticeable structural changes such as laser or surgery [43, 44]. Instead, the HIFEM mainly worked on the pelvic muscle instead of the urethral. Hence, we used transvaginal sonography to measure parameters of vaginal topography, including vaginal width, vaginal area, and levator hiatus. To our excitement, the distal vaginal width (rest and stress), proximal vaginal area (rest and stress), middle vaginal area (rest and stress), distal vaginal area (rest and stress), levator hiatus area (rest and stress) and levator hiatus short axis (stress) all showed significant change after HIFEM treatment in the 6-months treatment (Table 6). The data revealed that HIFEM technology could significantly improve PFM integrity and enhance the function of PFM. The data on vaginal topography also echoed the result of patients’ self-assessments.
In conclusion, our study showed that HIFEM treatment significantly improved SUI symptoms on pad tests and patients’ self-assessments in the 6-month follow-up. Besides, the data from urinary-related validated questionnaires, including OABSS, UDI-6, IIQ-7, and ICIQ-SF, showed a significant reduction. Then, the analysis of the urodynamic study revealed that only MUCP and UCA significantly increased after the six sessions of HIFEM treatment. The urethral and vaginal topography were performed and found that HIFEM mainly worked on PFM and enhanced its function and integrity. Our results suggest that HIFEM technology is an efficacious therapy for treating SUI.