Study design, materials and methods
The clinical data of patients who underwent AUS implantation in multiple medical centers from March 2019 to March 2022 were retrospectively analyzed. All the patients were male. The average course of disease was 40.2 months（ranging 11-120 months）. The average age was (69.1 ± 13.1) years. The median number of pads used was 4.5 (3.25,6.5). The preoperative maximum urethral pressure (MUP) was (79.6 ± 27.9) cmH2O, and the maximum urethral closure pressure (MUCP) was [51 (40.5, 73.5)] cmH2O. AUS implantation was performed through a single perineal incision in all patients. The sleeve size was mainly determined by the measured urethral circumference of the patient. After installation of all components, the urethral pressure profilometry was performed under the state of device inactivation and activation. The pump was activated 6 weeks after the operation, and telephone follow-up was performed 3 months after the activation of the device. The urinary control and complications were recorded. The results of follow-up were compared with the results of urethral pressure profilometry, and the preliminary conclusions were drawn.
Results
In this study, 3 patients (17.6%) received 4.0cm cuffs, 12 patients (70.6%) received 4.5cm cuffs, and 2 patients (11.8%) received 5.0cm cuffs. The MUP and MUCP of AUS device in inactivated state were (83.9±29.2) cmH2O and 53 (49,86) cmH2O. In the activated state, MUP was (139.9±22.6) cmH2O and MUCP was 110.0 (100.5, 134.5) cmH2O. Compared with that before operation, the urethral pressure in the inactivated state did not increase significantly (all P > 0.05), while the urethral pressure in the activated state increased significantly (all P < 0.001). The average follow-up after operation was 18.4 months. Fifteen patients (88.2%) used the initial installation device, and all of them met the standard of social continence. One patient died of cerebrovascular accident. One patient took out the device due to urethral erosion. The incidence of complications was 23.5% (4/17), including painless hematuria in 2 cases, scrotum and penis infection in 1 case, and urethral erosion in 1 case. The MUP and MUCP of these patients were (100.0 ± 40.7) cmH2O and (80.8 ± 39.7) cmH2O respectively. In the intraoperative active state, the MUP was (151.5 ± 15.3) cmH2O and the MUCP was (123.0 ± 17.2) cmH2O. The MUP of the other 3 patients in the device activation state was significantly higher than the average value, and all of them were above 150cmH2O, except one patient who was infected due to cognitive problems and chronic urinary retention. In 13 patients without complications, the MUP and MUCP were (79.0 ± 24.8) cmH2O and (59.5 ± 21.9) cmH2O respectively. In the intraoperative active state, the MUP was (136.4 ± 23.7) cmH2O and the MUCP was (112.9 ± 30.7) cmH2O.
Interpretation of results
After matching the complications of the patients with the results of intraoperative urethral pressure profilometry examination, it can be seen that the MUP of the 2 patients with painless gross hematuria under activated state is above 150cmH2O, which is more than 10cmH2O higher than the average. The MUP of patients with urethral erosion was higher than 160cmH2O in the activated state and close to 120cmH2O in the inactivated state, which was higher than the mean of 40cmH2O. In addition, the periurethral diameter measured during the operation of this patient was 4.2cm, and the cuff size selected for implantation was 4.0cm. All the above results indicate that the pressure provided by the device to the urethra is constantly high, which is an important cause of urethral erosion.