Application of modified urethral separation method in artificial urethral sphincter implantation and its influence on intraoperative urethral pressure profilometry

Abstract

Objective: To explore the application of modified urethral separation method in artificial urethral sphincter (AUS) implantation in patients with stress urinary incontinence (SUI), and its influence on the results of urethral pressure profilometry. Methods: A prospective collection of clinical data was conducted on 25 patients with stress urinary incontinence who underwent modified urethral separation method in AUS implantation and underwent urethral pressure profilometry in Beijing Hospital, Beijing Jishuitan Hospital Affiliated to Capital Medical University and the Second Hospital Affiliated to Tianjin Medical University from March 2019 to June 2023. The improved urethral separation method was to borrow part of the white membrane tissue of the cavernous body while freeing the dorsal side of the cavernous body of the urethra. The circumference of the urethra, sleeve size, and urethral pressure were recorded, the patient's autonomous urinary control before and after surgery and the changes of the international consultation on incontinence questionnaire-short form (ICI-Q-SF) score, incontinence quality of life questionnaire (I-QoL) score, urinary frequency score, nocturia score were compared. Follow-up was conducted in the clinic or by telephone at 1, 3, 6, and 12 months after activation of the device, and once a year thereafter. Local skin status and urine control were assessed, residual urine volume was measured by ultrasound and subjective score scale was completed. Results: All patients were male, aged 27-85 (65.8±15.7) years old. The circumference of the cuff used in this study was 4.0 cm in 4 patients (16.0%), 4.5 cm in 16 patients (64.0%), 5.0 cm in 4 patients (16.0%), and 5.5 cm in 1 patient (4.0%). Among them, the urethral circumference matched the cuff size in 14 cases (56.0%), the urethral circumference was smaller than the cuff size in 4 cases (16.0%), and the urethral circumference was larger than the cuff size in 7 cases (28.0%). Preoperative urodynamic examination showed that the maximum urethral pressure (MUP) was (78.0±25.9) cmH2O, (1 cmH2O=0.098 kPa) and the maximum urethral closure pressure (MUCP) was (53.4±26.6) cmH2O. The MUP of AUS device in the inactivated state was (88.0±26.5) cmH2O, which was not significantly higher than that before operation (P>0.05). The MUCP was (68.2±24.5) cmH2O, which was significantly higher than that before operation (P<0.05). The MUP and MUCP of the AUS device in the activated state were (146.6±25.2) cmH2O and (123.0±28.3) cmH2O, which were significantly higher than those before surgery and in the inactivated state (both P<0.001). All patients in the group reached the social urinary control standards at the first month of device activation. During a follow-up period of 2-50 months, 22 patients (88.0%) used the initial AUS device and all met social urinary control standards. The AUS device was replaced in 1 case. One patient died of cerebrovascular accident. One patient removed the device due to complications. The number of pads [M (Q1, Q3)] used in 25 patients before and after operation was 4.5 (3.0, 6.5) and 1 (0, 1) respectively, with statistically significant differences (P<0.001). ICI-Q-SF score, I-QoL score, urinary frequency score and nocturia score of 25 patients were significantly improved after surgery (all P<0.05). The incidence of postoperative complications was 20.0% (5/25), including 2 cases of painless hematuria, 1 case of infection, 1 case of urethral erosion, and 1 case of dysuria. Except for one patient who experienced urethral erosion and had his sleeve removed, the remaining four patients regained social urination control with active support treatment, and no symptoms recurred until the last follow-up. Conclusion: The modified urethral separation method has no significant effect on urethral pressure in patients with SUI, and can increase the volume of peri-urethral tissue in the cuff, thereby reducing the risk of intraoperative urethral injury and the incidence of postoperative urethral erosion.