Urinary incontinence after RP is a common complication that has a severely adverse impact on patients’ quality of life and requires more care [19]. Scholars are constantly trying to find a reliable way to reduce the occurrence of urinary incontinence after RP. A series of strategies have been adopted to treat postoperative urinary incontinence, including PFME and surgical interventions [20]. Numerous studies have demonstrated that PFME is the most common conservative intervention for postoperative urinary incontinence [13, 21,22,23]. Although it is generally believed that PFM contractions can be achieved after verbal or written instructions for PFME, up to 50% of patients fail to achieve effective contractions after basic instructions [24]. Therefore, there is an urgent need to improve the effectiveness of PFME and to standardize guidance.

In the current study, based on research and practice, patients in the TUUD-guided PFME group achieved better urinary continence than those in the control group. Of the 50 patients in the observation group, 26 patients (52.0%) achieved urinary continence after catheter removal (2 weeks after RP), which was significantly higher than that in the control group (29.7%). In addition, urinary continence rates at 1, 3, 6 and 12 months after RP in the observation group were all higher than those in the control group. Although previous studies reported a controversial influence of PFME on improving postoperative urinary continence [24], our data demonstrated an effective influence of TUUD-guided PFME on immediate, early and long-term urinary continence recovery after RP. To improve postoperative urinary continence, modified PFME was administered. Centemero, A et al. initiated PFME before RP and observed an improved early continence rate compared with postoperative PFME [25]. Seong J. et al. developed a series of nomograms to predict the recovery of urinary continence after RP and achieved significant improvement in continence [26]. Ultrasound-guided PFME was reported to not only improve the early incontinence recovery with a continence rate of 52.8% within 30 days after RP, but also the prolonged urinary incontinence occurring > 1 year later [27, 28]. Compared with these studies, our study revealed outstanding immediate and early continence rates under postoperative TUUD-guided PFME, as well as late continence rates. By means of transrectal ultrasound, we clearly observed the EUS contraction and guided the maximum external urethral sphincter contraction training by the digital rectal examination during PFME, which indicated that correct PFME is vital for urinary continence recovery after RP. Furthermore, correct PFME would provide long-term benefits in urinary continence for patients. However, a major bias in timing of PFME training in the two groups in this retrospective study existed, and the role of TUUD-guided PFME in improving urinary continence recovery after RP still needed to be further verified in prospective study in which synchronous PFME was required.

At the time of transrectal ultrasound examination, the maximum EUS contraction was measured. According to the algorithms we formulated, the contractile function of EUS after PFME was classified into decreased and normal. In the transrectal ultrasound and urologist_dually guided PFME cohort, the 2-week, 1-month, 3-month, 6-month and 12-month continence rates in the decreased group were obviously lower than those in the normal group, which indicated that the EUS contraction amplitude was a promising index for predicting postoperative urinary continence after RP. Stéphanie J. et al. reported that the thickness, cross-sectional area and volume of the urethral sphincter were increased in women after a 12-week group PFM rehabilitation intervention [29], which was similar to our study. It has been reported that > 90% of patients with long-term urinary incontinence have EUS impairment [30]. Therefore, a decreased contraction after precise PFME reflected the possibility of EUS impairment that may need other treatments. With the help of transrectal ultrasound, detecting EUS contraction was easy. Meanwhile, compared with determination of the membranous urethral length determined by MRI, the EUS-guided contraction by ultrasound required a lower cost. In addition, with the application of micro-ultrasound in urology, assessment of EUS contraction would be more precise and easier in the future [31]. However, because of the limited sample size of this study, this assessment method of the EUS contraction requires a large sample size for further verification.

Finally, we conducted an analysis of factors influencing immediate, early and long-term urinary continence after RP. Our data revealed that TURP and TUUD-guided PFME were associated factors for urinary continence at 2 weeks and 1, 3, 6 and 12 months after RP. TURP has been verified by previous studies to have adverse influences on urinary continence possibly because of the fibrosis of periurethral tissues that may inhibit EUS function [32]. Therefore, maintaining the integrity of the EUS and strengthening EUS training are vital during the perioperative period. TUUD-guided PFME was verified to be an independent factor in predicting immediate, early and long-term continence, which was partly because of the quick and correct recovery of the EUS function under the current model of PFME.

In conclusion, our data verified the effectiveness of TUUD-guided PFME in improving urinary continence after RP and the possibility of using EUS contraction in predicting urinary continence. In addition, no assistive devices were used in the current model, and training without equipment was carried out before the urinary catheter was not removed, which improved the rate of voiding control after removal of the urinary catheter.

There were still some shortcomings in this study. First, this was only a retrospective single-center study with a small sample size. Multicenter, large-scale and prospective research is needed to further verify the effectiveness of current model of PFME. Second, this study only focused on the recovery of the patient’s body, and did not introduce psychological status evaluation, which needs to be assessed in the future.