INTRODUCTION
Benign prostatic hyperplasia (BPH) is a common condition in elderly men and its prevalence increases with age [1]. Medical therapy is recommended as the initial treatment option for patients with moderate-to-severe lower urinary tract symptoms (LUTS) who do not meet the criteria for surgical intervention [2]. Surgical treatment is considered if medical therapy fails [3]. Surgical treatment options for BPH include transurethral resection of the prostate (TURP) and holmium laser enucleation of the prostate (HoLEP) [4]. Despite its challenging learning curve, HoLEP has been shown to improve postoperative outcomes compared with TURP. It is known for its advantages, such as shorter catheterization time, shorter hospital stay, and lower blood transfusion rates [5-7].
However, HoLEP involves close proximity of the urethral sphincter during enucleation, which can lead to postoperative urinary incontinence (UI) due to urethral sphincter damage caused by the resectoscope during surgery [8]. UI is mostly transient but remains a significant complication that impairs patients’ quality of life [9]. Previous studies have investigated UI rates following HoLEP, but there is considerable variation in UI rates across studies (3.9%–21.0%) [10-14]. This is because there is no standardized method for investigating the definition, type, severity, or timing of UI occurrence across studies. To date, systematic studies investigating the type, severity, and timing of UI after HoLEP are lacking. Therefore, this study aimed to conduct a thorough investigation of UI occurring after HoLEP based on postoperative timing, incontinence type, and severity.
MATERIALS AND METHODS
Patients
From January 2010 to June 2022, a prospective registry-based patient cohort study was conducted at Seoul National University Hospital, involving patients who underwent HoLEP by a single surgeon (SJO). We obtained and analyzed the database accordingly.
The inclusion criteria consisted of patients diagnosed with BPH aged 50 years or older who met surgical indications and underwent HoLEP. Patients with genitourinary malignancies or neurogenic lower urinary tract dysfunction were excluded. Patients with minimal neuropathy, determined based on medical history and physical examination to have minimal impact on LUTS, were included in this study.
Study Design
Baseline demographics, including age and comorbidities such as diabetes, hypertension, and cardiovascular diseases, were assessed in an outpatient setting. Preoperative evaluation included physical examinations, including a digital rectal examination (DRE), as well as assessments using the International Prostate Symptom Score (IPSS) and the Overactive Bladder Symptom Score (OABSS). To exclude infection, urinalysis and urine culture were performed and prostate volume was measured using transrectal ultrasound imaging (TRUS). Uroflowmetry (UFM) with ultrasound measurement of postvoid residual urine volume (PVR) and urodynamic studies (UDS) were conducted to evaluate urological function [15]. A prostate-specific antigen (PSA) test and TRUS-guided prostate biopsy (if necessary) were performed to exclude prostate cancer. In cases where a palpable nodule was detected on DRE, or prostate cancer was clinically suspected due to elevated PSA levels, a preoperative prostate tissue biopsy was performed to rule out prostate cancer. Since 2016, preoperative multiplanar magnetic resonance imaging has been conducted, and if abnormalities are identified, a tissue biopsy is performed prior to HoLEP surgery.
We investigated operative outcomes, including total operation time, enucleation time, morcellation time, and resected prostate volume, and perioperative outcomes, including Foley catheter duration and length of postoperative hospital stay. We conducted regular follow-up protocols at 2 weeks, 3 months, and 6 months postoperatively, and measured IPSS, OABSS, UFM data, and PVR at each follow-up. Six months postoperatively, we conducted a patient satisfaction survey regarding the surgical outcomes [16]. After HoLEP surgery, UI was assessed using a patient-reported assessment method. In cases where patients reported UI, the type and severity of UI were investigated in detail and documented in the electronic medical records. UI was classified as stress UI (SUI) or urgency UI (UUI). The severity of UI was defined as follows: cases managed with behavioral modifications, including Kegel exercises or bladder training, were categorized as mild; cases requiring medication (such as anticholinergics and imipramine) and behavioral modifications due to patient needs were categorized as moderate. Severe cases were defined as those requiring surgical or endoscopic intervention [17]. We defined ‘De novo UUI’ as cases where there was no UUI before surgery, but UUI occurred after surgery.
We categorized patients into 3 groups based on preoperative prostate volume: group A (30–80 mL), group B (81–120 mL), and group C (120 mL and above). We then compared patient demographics, operative outcomes, perioperative outcomes, postoperative functional outcomes, and UI rates across these groups.
Surgical Methods
Patients were placed in the lithotomy position under spinal or general anesthesia. Surgery was performed using a Ho:YAG laser (VersaPulse PowerSuite 100 W, Lumenis Pulse 120H, Yokneam, Israel) set to 80 W (2 J, 40 Hz). Initial incisions were made at the 5 and 7 o’clock positions on the bladder neck, followed by a transverse incision immediately above the verumontanum. A 3-lobe technique was used as the standard procedure [18,19]. After meticulous bleeding control, morcellation was performed using a 26Fr nephroscope and tissue morcellator (Versacut, Lumenis). A 22Fr 3-way Foley catheter was placed under continuous irrigation and removed on the first postoperative day. Typically, the patient was discharged on the first postoperative day.
Statistical Analysis
Data were analyzed using IBM SPSS Statistics ver. 26.0 (IBM Co., Armonk, NY, USA). All data were presented as mean±standard deviation. To compare the clinical parameters of each group, analysis of variance was used for continuous variables, and chi-square tests were used for categorical variables. Logistic regression analysis was performed to identify factors influencing de novo UUI. The chi-square method was used to examine the association between the presence of UI and self-administered questionnaires 6 months after surgery. Statistical significance was defined as P<0.05.
RESULTS
Patient Demographics and Operative and Perioperative Outcomes
A total of 1,675 patients with BPH were identified. Group A included 1,063 patients, group B included 423 patients, and group C included 189 patients (Table 1). There was no significant difference in the preoperative total IPSS score based on prostate volume (P=0.32). However, the preoperative OABSS increased with larger prostate volumes (P<0.01). Preoperative UDS showed that the frequency of detrusor overactivity (DO) increased with larger prostate volume (P<0.01).
Efficacy
The postoperative functional outcomes and results of the 3 self-administered questionnaires are shown in Table 2. At 2-week and 3-month postsurgery, the total IPSS showed significant improvement over the preoperative values in all groups (P<0.01), with larger prostate volumes associated with lower total IPSS (P<0.01). There were no significant differences in the OABSS at 2-week and 3-month postsurgery based on the prostate volume (P=0.66 and P=0.46).
At 6-month postsurgery, the total IPSS showed significant improvement compared with the preoperative values in all groups (P<0.01). However, when comparing the groups, group B had the lowest total IPSS score at 6-month postsurgery (P<0.01). At 6-month postsurgery, the OABSS, maximum flow rate, and PVR showed significant improvement in all groups compared with the preoperative values (P<0.01). There were no significant differences in the OABSS between the groups at 6-month postsurgery (P=0.73).
Urinary Incontinence
The preoperative UUI rate was identified in 270 patients (16.1%), with no significant difference in the UUI rate based on prostate volume (P=0.81) (Table 3). Two weeks postoperatively, the UUI and de novo UUI rates were 6.0% and 4.2%, respectively. There were no significant differences in UUI rates between the groups at 2 weeks postsurgery (P=0.76) (Fig. 1). The postoperative UUI rate showed a continuous decrease at 2 weeks, 3 months, and 6 months (P<0.01). At 6-month postsurgery, UUI occurred in 15 patients (0.9%), with no significant differences based on prostate volume (P=0.69).
None of the patients had preoperative SUI. Two weeks postoperatively, SUI was identified in 112 patients (6.7%), with mild and moderate degrees at 6.2% and 0.5%, respectively. The SUI rate increased with larger prostate volume (P=0.04) (Fig. 1). The SUI rate continued to decrease at 3- and 6-month postsurgery (P<0.01). At 6-month postsurgery, SUI occurred in 20 patients (1.2%), with the lowest rate in group A (P=0.02). No patient required secondary surgeries for SUI, including bulking agents, male sling, or artificial urinary sphincter insertion.
In the logistic regression analysis to identify factors influencing de novo UUI at 2 weeks postsurgery, age and DO in the preoperative urodynamic study showed borderline significance (P=0.064 and P=0.060) (Supplementary Table 1). The results of the subjective satisfaction survey of patients 6 months after HoLEP, based on the presence or absence of UI, are listed in Supplementary Table 2. Patients without SUI had significantly higher satisfaction with the overall response assessment (ORA) than those with SUI (P=0.001). Similarly, patients without UUI were significantly more satisfied with the treatment satisfaction question (TSQ) than those with UUI (P=0.006). Postoperative complications other than UI are listed in Supplementary Table 3.
DISCUSSION
UI following HoLEP can negatively affect a patient’s quality of life [20]. According to Ibrahim et al. [11]’s prospectively collected database (n=1,476), the incidence of UI within 1 month after HoLEP was 4.3% and the rate of persistent UI lasting over 12 months was 0.8%. These data are limited because they do not distinguish UI by type or degree. In a prospective trial by Gilling et al. [12], the postoperative UI rate was 21% (n=38). While these data are from a prospective study, they are limited by the small number of patients and the lack of differentiation by follow-up periods. According to a retrospective study by Krambeck et al. [13] (n=1,065), the SUI rate was 4.8% and the UUI rate was 2.2% at follow-up periods >5 years postoperatively. These data distinguish UI by type but lack differentiation by degree, which is a limitation. Previous studies have rarely distinguished between SUI and UUI.
In our previous study [20], preoperative UUI was confirmed in 25 of 204 patients (12.3%). In the present study, the preoperative UUI rate among 1,675 patients was 270 (16.1%), and at 2 weeks postoperatively, the UI rates were similar for SUI (112 cases, 6.7%) and UUI (100 cases, 6.0%). Cho et al. [20] reported SUI rates of 9.5% and UUI rates of 10.1% at 2 weeks postoperatively. The lower UI rates in our study compared with those reported by Cho et al. (n=204) may be attributed to the larger sample size and inclusion of patients who underwent surgery by a single surgeon, resulting in a different patient population. Cho et al. used the conventional three-lobe technique, whereas our study used the sphincter-saving technique starting in 2013 [8, 20]. In this study, at 6 months postoperatively, the SUI and UUI rates were 1.2% and 0.9%, respectively, showing similar rates of SUI and UUI. Furthermore, our results showed that most UI at 6 months postoperatively were mild, with very low rates of moderate SUI (0.1%) and UUI (0.4%) treated with medications such as anticholinergics or imipramine upon patient request. In contrast to Cho et al., our study extensively differentiated UI according to the degree.
Studies have conflicting opinions regarding the effects of prostate volume on UI after HoLEP. Humphreys et al. [21] conducted a retrospective study (n=507) by dividing prostate volume into groups of 75 ml or less, 75–125 mL, and 125 mL or more and reported that prostate volume did not affect UI. Krambeck et al. [22] conducted a retrospective study in 57 patients with a prostate volume of 175 mL or more and reported that there was no persistent UI at follow-up 6 months after surgery. These studies were limited by their small sample sizes. However, studies have shown that prostate volume affects the risk of UI. Hout et al. [23] conducted a meta-analysis and found that UI increased at prostate volumes ≤80 mL, only short-term UI increased when the prostate volume exceeded 80 mL. A retrospective study (n=1,288) conducted by Xu et al. [24] reported that UI increased when the prostate volume was 90 mL or more compared with when the prostate volume was 90 mL or less. A result of a retrospective study (n=589) by Das et al. [25] reported that SUI at 3 months after HoLEP surgery was related to prostate size >100 g. In this study, the SUI rate 2 weeks after surgery increased as the prostate volume increased (group A, 59 [5.6%]; group B, 33 [7.8%]; group C, 20 [10.6%]; P=0.04).
SUI after surgery is presumed to be caused by damage to the urethral mucosa due to endoscopic manipulation or mucosal fibrosis at the surgical site [8]. Additionally, mechanical dilatation of the urethra is caused by the endoscopic instruments used during the HoLEP procedure, which can easily lead to transient UI [26]. The larger the prostate volume, the longer the duration of endoscopic manipulation and the greater the range of motion, making mechanical dilatation of the urethra more likely [23]. SUI almost disappeared by 6 months after surgery and remained mostly mild. In this study, unlike UUI, the incidence of SUI increased as prostate volume increased. Therefore, in patients with a large preoperative prostate volume, sufficient warning regarding the possibility of postoperative SUI is necessary.
DO is one of the most common causes of UUI after transurethral prostatectomy [20]. This mechanism appears to be due to changes in the bladder response caused by feedback from the resected prostatic urethra [27]. Patients with an overactive bladder due to DO can be continent before surgery, but UUI may persist in the presence of DO even if the obstruction is resolved after surgery [28]. However, there are reports that half of the patients complaining of UUI did not have DO during UDS [29]. Additionally, the presence of DO and the response to OAB drug treatment in patients with UUI were not related [30]. Age and the presence of DO on preoperative urodynamic testing were borderline significant factors affecting de novo UUI. Therefore, in elderly patients and patients with DO on UDS, caution is needed regarding the possibility of postoperative UUI. Additionally, our results showed that de novo UUI decreased over time at 3 and 6 months postoperatively and was not significantly related to DO. This can be seen as a process that normalizes over time because the bladder response to bladder outlet obstruction disappears after surgery. It is important to note that the ultimate treatment for preoperative UUI is active management of bladder outlet obstruction with surgery rather than medication.
In this study, the proportion of patients without SUI who responded positively to the ORA was significantly higher than that of patients with SUI. In addition, the proportion of patients without UUI who responded positively to the TSQ was significantly higher than that of patients with UUI. This is consistent with the results of a study by Lee et al. [16] in which patients who were highly dissatisfied after HoLEP surgery responded that UI was the cause of their dissatisfaction.
The limitations of this study were as follows. First, midterm follow-up was performed only up to 6 months after surgery, and long-term follow-up was not possible. Unlike oncological diseases, BPH is a benign disease; therefore, long-term follow-up for more than 6 months is difficult. Second, the UI rate after HoLEP was investigated using patient-reported assessments rather than questionnaires. However, despite these limitations, the advantage of this study, unlike previous studies, was that it classified the UI rate after HoLEP surgery by type into SUI and UUI. In addition, we believe that the accuracy of UI incidence will be higher than that of the existing retrospective studies by applying a consistent follow-up protocol through the Registry-based Patient Cohort Study under Regular Follow-up, targeting a large number of patients.
In conclusion, our results demonstrated that the preoperative UUI rate was high at baseline. Both the UUI rate (including the de novo UUI rate) and SUI rate continuously decreased up to 6 months postoperatively. Although the SUI rate significantly differed according to prostate volume, there was no significant difference in the UUI rate.
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