The pathophysiology of PRPUI is complicated including various factors. Anatomically compromised urethral sphincter complex, secondary functional changes resultant from neural or vascular damage are responsible for PRPUI. Considering possible impaired contractility, hidden emptying disorder should also be in the count. Furthermore, patients’ old age may also be factors responsible for various types of LUTS after AUS implantation. Therefore, for some patients, the only successful redemption of the compromised urethral component may not result in the completely satisfactory condition.
Plenty of literature has reported surgical outcome of AUS focusing just on the continence. However, there is little information on the prevalence, predictive risk factors, or long-term clinical course on the post AUS LUTS which might be indispensable for preoperative counseling and postoperative management.
According to a recent consensus report, the pre-AUS urodynamic study is recommended for patients with noticeable bladder disorder suspicious of low compliance or decreased contractility. However, to notice potential bladder dysfunction ahead of AUS implantation is not always possible for every PRPUI patient, as incontinence itself may obscure the intrinsic disorder.
Dr. Lee and team investigated lower urinary tract symptoms observed after AUS implantation among PRPUI patients. They have analyzed post AUS LUTS in association with preoperative urodynamic parameters to find out the predictive factor of post AUS LUTS using objectively quantifiable questionnaires.
This study was retrospectively evaluated. Only virgin cases of single cuff AUS applied on the proximal bulbous urethra, performed after radical prostatectomy, were included in the assessment. Cases followed by reoperation or cases with endoscopically proven atrophy or erosion were excluded. And cases with follow up less than 6 months after device activation were also excluded from the assessment. All the patients received urodynamic study before AUS implantation. The 61-70cmH2O pressure regulating balloon were placed at pre-peritoneal space. For all the patients, cycling test was performed, after components connection, under urethroscopy to confirm device function and good coaptation. The device was deactivated for 6 weeks, and after activation of device, periodic outpatient assessment was followed. LUTS were assessed using Sandvik-incontinence severity index (Sandvik-ISI), overactive bladder symptom score (OABSS), and international prostate symptom score (IPSS).
There was a total of 104 patients were included in the investigation. The mean age at AUS implantation was 73.1 (56.6~84.9) years old, the mean follow up length was 45.4 (7.9~118.2) months after AUS implantation. Pre-AUS urodynamic study was performed at the mean period of 34.8 (4.0~194.5) months after radical prostatectomy, and AUS implantation was performed at the mean period of 38.8 (6.6~195.0) months after radical prostatectomy. The mean age at latest follow up was 79.6 (61.9~93.4) years old.
At the latest outpatient visit, 10.9 % (11/101) had very severe urinary incontinence corresponding to Sandvik-ISI score 12, 51.0 % (53/104) had overactive bladder (OAB) corresponding to OABSS urgency score ≥2 with total OABSS score ≥3. 18.2% (18/99) had severely symptomatic LUTS corresponding to IPSS score ≥ 20 points. 32.7% (34/104) patients were taking medication for the treatment of overactive bladder symptoms.
The preoperative urodynamic parameters and postoperative symptom scores, maximum cystometric capacity had a significant negative correlation with OABSS-urgency (P=0.012, rho=-0.246), detrusor pressure at end-filling had a significant negative correlation with IPSS-straining to void (P=0.032, rho=-0.216). Among the voiding phase urodynamic parameters, detrusor pressure at peak flow showed significant positive correlation with OABSS-urgency score (P=0.032, rho=0.222). On the other hand, projected isovolumetric pressure (PIP) (PdetQmax+5Qmax) and modified PIP (PdetQmax+Qmax) had no correlation with any item of questionnaires (Table 1). The presence of involuntary detrusor contraction had a significant association with OAB; defined as OABSS urgency score more than point 2 with a total score more than point 3 (P<0.001), OABSS-urgency (P<0.001) and OABSS-urgency urinary incontinence (P=0.002) (Figure 1).
There was significant correlation between the patient age at latest visit and nocturia (OABSS;P=0.017, rho=0.235, IPSS;P=0.050, rho=0.198), weak stream (IPSS;P=0.048, rho=0.199) and voiding symptoms (IPSS;P=0.044, rho=0.203). However, there was no significant correlation between follow up period after AUS implantation and LUTS scores.
The bladder compliance itself had no correlation with any item of post AUS LUTS. Close surveillance of the bladder and upper urinary tract condition might be followed after AUS implantation for the patients with low bladder compliance before AUS implantation. As both the Qmax and PdetQmax are related to urethral resistance, to assess the bladder contractility with PIP or modified PIP, calculated using Qmax and PdetQmax, may not be appropriate for the PRPUI patients.
After AUS implantation for PRPUI, diverse storage and even voiding symptoms were observed, which were overlooked for a long time. Pre-AUS urodynamic parameters, like detrusor overactivity, small bladder capacity, high detrusor pressure at end-filling could predict the post-AUS LUTS. Therefore preoperative urodynamic evaluation may be valuable for prediction of surgical outcome and counseling the patients prior to AUS implantation. Furthermore, as the population with PRPUI-AUS is in their old age, the aging effect on the lower urinary tract function might also be considered in managing the patients.
Presented by: Hee Seo Son, Kim M J, Kim J H, Department of Urology and Urological Science Institute, Yonsei University College of Medicine, Severance Hospital, Seoul, Korea
Written by: Bilal Farhan, MD; Clinical Instructor, Female Pelvic Medicine and Reconstructive Surgery, University of California, Irvine Medical Center, Twitter: @Bilalfarhan79 at the 2018 ICS International Continence Society Meeting - August 28 - 31, 2018 – Philadelphia, PA USA