Short-Term Clinical Outcomes of Bladder Neck Incision at Time of Holmium Laser Enucleation of the Prostate

Abstract

Introduction:

The effect of prophylactic bladder neck incision (BNI) at time of holmium laser enucleation of the prostate (HoLEP) is unknown. The aim of our study was to examine HoLEP outcomes with a specific focus on rates of bladder neck contractures (BNCs), with and without utilizing prophylactic BNI.

Materials and Methods:

We performed a retrospective review of HoLEP patients from January 2021 until January 2022. Outcomes of patients who underwent BNI at time of HoLEP were compared with those who underwent standard HoLEP alone. Student's t-tests, chi-square tests, and logistic regressions were performed using SAS Studio.

Results:

In total, 421 patients underwent HoLEP. BNI was concurrently performed in 74 (17.6%) HoLEP patients. BNI patients were younger (67.5 ± 9.0 years vs 71.1 ± 8.2 years, p = 0.00007) and had smaller prostates (60.7 ± 30.3 cc vs 133.2 ± 64.5 cc, p < 0.0001). Procedure, enucleation, and morcellation times were shorter in the BNI group (all p < 0.0001). There was no statistical difference in same-day discharge rates (90.4% vs 87.7%, p = 0.5), short-term functional outcomes, emergency department (ED) visits, or readmission rates between the two groups. At 14 months mean follow-up, two BNCs occurred in patients in the control group (0.6%), and no BNCs occurred in patients who underwent BNI (0.0%, p = 0.5).

Conclusions:

BNI at time of HoLEP did not decrease the ability to achieve same-day discharge or increase 90-day complications, ED visits, or readmission rates. No BNCs occurred in patients who underwent prophylactic BNI (0.0%) despite a smaller gland size and lower specimen weight in this cohort. Further prospective studies are required to conclude if concurrent BNI at time of HoLEP is protective against BNC.

Introduction

Holmium laser enucleation of the prostate (HoLEP) is a size-independent surgical treatment option for benign prostatic hyperplasia (BPH).¹ One main advantage of HoLEP is the ability to treat patients with very large prostates, with low rates of morbidity relative to simple prostatectomy.¹ In addition to treating patients with very large prostates, HoLEP can also be offered to patients with “small” prostates (<30 g).¹ In a series of more than 1000 HoLEPs, a correlation was identified between small gland sizes and postoperative bladder neck contracture (BNC) development.² The authors identified that patients who developed a BNC had a mean enucleated specimen weight of 38.5 g. In an attempt to prevent postoperative BNC, the authors began routinely performing prophylactic bladder neck incision (BNI) during HoLEP on patients with glands less than 40 cc in size.²

It has been previously demonstrated that prophylactic BNI after transurethral resection of the prostate (TURP) in glands <20 cc decreased the BNC rate from 7.5% (12/161) to 0.87% (n = 1/114).³ Unfortunately, examining rates of BNC after HoLEP is more difficult than after TURP due to a lower incidence of postoperative BNC. Previous retrospective HoLEP series have demonstrated BNC rates of 1.6% to 2.1% with approximately half occurring within the first year of follow-up.^4,5

Our current practice is to perform prophylactic BNI at the time of HoLEP in patients who have a narrow bladder neck opening after laser enucleation. BNIs are performed in an attempt to decrease rates of postoperative BNCs. We currently do not utilize an exact prostate size cutoff to decide when to perform BNI after HoLEP. Instead, it is a judgment decision on the part of the surgeon based on the appearance of the post-enucleation bladder neck. The aim of our study was to describe contemporary HoLEP postoperative outcomes of patients, with a focus on rates of BNC, in high-volume practice with and without utilization of prophylactic BNI.

Materials and Methods

Overview

Patients undergoing HoLEP at Northwestern University are consented to enroll into a prospectively maintained database with institutional review board approval. We retrospectively reviewed patients in our database who underwent HoLEP between January 2021 and January 2022 (to allow for sufficient follow-up to detect BNCs). Patients who received concurrent BNI at time of HoLEP were compared with those that did not. All HoLEPs were performed by one expert surgeon at a single center using a 120 W Moses™ 2.0 Laser and technique previously described.⁶ BNIs were performed at the surgeon's discretion for a narrow appearing bladder neck after prostate enucleation. BNIs were performed with the holmium laser using the laser settings 2.0 J and 50 Hz and incising at the 3-, 6-, and 9-o'clock bladder neck positions. BNIs were started proximally from the bladder neck and carried distally to the mid-prostatic fossa. The BNIs were deepened with multiple passes of the laser until the bladder neck fibers were visibly incised and the bladder neck adequately opened. Postoperatively, same-day discharge HoLEP was performed as previously reported by our group.⁶

Preoperative variables included age, body mass index, American Society of Anesthesiology (ASA) score as a surrogate for comorbidity, anticoagulation use, history of BPH surgery, prostate size, and prostate serum antigen. Intraoperative variables included: procedure, enucleation, and morcellation time, total energy, and operating room (OR) specimen weight. Postoperative variables included same-day discharge rate and 90-day complications, emergency department (ED) visits, and readmission rates.

Outcomes

The primary outcomes of our study were to assess the rate of postoperative BNC and the rate of successful same-day discharge. The secondary outcome was to assess the 90-day complication rates, ED visits, and readmissions. We defined BNCs as a bladder neck stenosis/contracture visualized on follow-up cystoscopy or obstructive symptoms requiring a secondary BNI procedure. To better characterize the BNI group, we performed additional subgroup analyses by examining a limited cohort with preoperative prostate size <55 cc and another limited cohort with OR specimen weights <55 g (cutoffs were based on prior studies;^4,7 Supplementary Tables S1 and S2).

Statistical analyses

The means of continuous variables were compared using Student's t-tests. Categorical variables were compared using chi-square tests. Variables that were statistically significant on univariate analysis were then incorporated into a multivariate logistic regression model. All statistical tests were two-sided, and a p-value of <0.05 was predetermined to be statistically significant. All analyses were performed using SAS Studio (SAS institute, 2021).

Results

A total of 421 patients underwent HoLEP during the study period; 74 patients were in the BNI group, and 347 patients were in the control group. Patients undergoing BNI were younger (67.5 ± 9.0 years vs 71.1 ± 8.2 years, p = 0.0007), higher preoperative American Urological Association Symptom Score (AUASS) (21.8 ± 7.2 vs 18.5 ± 8.0, p = 0.01), had lower ASA scores (48.7% were ASA 3 vs 54.6%, p = 0.027), and had smaller preoperatively assessed prostate size (60.7 ± 30.3 cc vs 133.2 ± 64.5 cc, p < 0.0001) compared with patients who did not undergo BNI (Table 1).

Table 1.

Perioperative Characteristics of the Bladder Neck Incision and Control groups

Variable	BNI group (n = 74)	Control group (n = 347)	Odds ratio	95% CI	p
Mean age (years)	67.5 (9.0)	71.1 (8.2)			0.0007
Mean body mass index (kg/m²)	27.8 (4.6)	27.5 (4.7)			0.63
ASA
1	2 (2.7)	0 (0.0)			0.03
2	36 (48.7)	155 (44.3)
3	36 (48.7)	191 (54.6)
4	0 (0.0)	4 (1.1)
Anticoagulation (yes/no)	18 (24.3)	74 (21.1)	0.83	0.46–1.50	0.50
Prior BPH surgery (yes/no)	9 (14.1)	55 (15.7)	1.34	0.63–2.86	0.40
Preoperative prostate size (g)	60.7 (30.3)	133.2 (64.5)			<0.0001
Preoperative AUASS	21.8	18.5			0.01
Preoperative MISI	6.1	6.0			0.46
Preoperative MISI bother	1.8	1.5			0.72
Prostate serum antigen (ng/mL)	4.47 (14.0)	7.44 (9.30)			0.11
Procedure time (minutes)	50.6 (32.2)	76.4 (30.7)			<0.0001
Enucleation time (minutes)	23.3 (21.1)	37.9 (14.7)			<0.0001
Morcellation time (minutes)	3.26 (3.34)	11.1 (10.2)			<0.0001
Total energy (kJ)	83.6 (58.1)	160.0 (463.8)			0.004
OR specimen weight (g)	24.3 (25.1)	82.6 (52.5)			<0.0001

Standard deviations of means are shown in parentheses. Percentages of categorical variables are shown in parentheses. Anticoagulation is routinely held before holmium laser enucleation of the prostate after consultation with the prescribing physician.

ASA = American Society of Anesthesiology score; AUASS = American Urological Association Symptom Score; BNI = bladder neck incision; BPH = benign prostatic hyperplasia; CI = confidence interval; MISI = Michigan Incontinence Symptom Index; OR = operating room.

The procedure, enucleation, and morcellation times were shorter in the BNI group (p < 0.0001 for all variables, respectively; Table 1). Furthermore, the total energy used was lower (83.6 ± 58.1 kJ vs 160.0 ± 463.8 kJ, p = 0.004), and the OR enucleated specimen weight was also less (24.3 ± 25.1 g vs 82.6 ± 52.5 g, p < 0.0001) for the BNI group compared with the control group, respectively.

To further characterize the BNI cohort, we restricted the cohort by prostate size only, which resulted in similar mean prostate sizes for the BNI and control groups: 42.0 ± 10.9 cc vs 38.7 ± 15.8 cc, p = 0.4, but OR specimen weight remained significantly different: 17.9 ± 12.0 g vs 53.5 ± 44.1 g, p < 0.0001 (Supplementary Table S1). Restricting the cohort by OR specimen weight only, resulted in significantly different mean prostate sizes: 54.8 ± 18.3 cc vs 84.9 ± 37.1 cc, p < 0.0001, as well as significantly different mean OR specimen weights: 19.0 ± 11.8 g vs 33.9 ± 12.8 g, p < 0.0001 (Supplementary Table S2).

Primary outcomes

There was no difference in same-day discharge rates between the BNI and control groups (90.4% vs 87.7%, p = 0.5; Table 1). The mean follow-up was 13.8 ± 2.8 months vs 14.1 ± 2.9 months (p = 0.4) for the BNI and control groups, respectively (Table 2). Only two patients in the entire cohort developed a BNC, both from the control group (0.0% vs 0.6%, p = 0.5; Table 2). The BNCs manifested as symptomatic recurrence of weak stream ∼7.5 months after HoLEP. Both BNC patients required secondary laser BNI procedures under a general anesthesia, with no subsequent recurrences to date.

Table 2.

Postoperative Outcomes of the Bladder Neck Incision and Control Groups

Variable	BNI group (n = 74)	Control group (n = 347)	Odds ratio	95% CI	p
Mean follow-up (months)	13.8 (2.8)	14.1 (2.9)			0.4
Bladder neck contracture (yes/no)	0 (0.0)	2 (0.6)	1.00	0.99–1.02	0.5
Same-day discharge (yes/no)	66 (90.4)	307 (87.7)	1.32	0.57–3.06	0.5
90-Day complications (yes/no)	8 (15.7)	33 (13.5)	0.86	0.38–1.94	0.7
Grade I	6 (75.0)	19 (57.6)			0.4
Grade II	2 (25.0)	13 (39.4)			0.5
Grade III	0 (0.0)	0			—
Grade IVa	0 (0.0)	1 (3.0)			0.7
Grade IVb	0 (0.0)	0			—
Grade V	0 (0.0)	0			—
90-Day ED visits (yes/no)	9 (12.2)	22 (6.3)	0.48	0.21–1.10	0.08
90-Day readmissions (yes/no)	3 (4.0)	10 (2.9)	0.7	0.19–2.59	0.6
Functional outcomes (last follow-up)
Postoperative AUASS	7.7	7.6			0.89
Postoperative MISI	4.6	3.4			0.46
Postoperative MISI bother	0.7	0.7			0.72
Time from OR to last follow-up (months)	3.4	3.7			0.37

Standard deviations of means are shown in parentheses. Percentages of categorical variables are shown in parentheses.

ED = emergency department.

Secondary outcomes

There was no difference in the 90-day complication rate (15.7% vs 13.5%, p = 0.7) or 90-day readmission rate (4.0% vs 2.9%, p = 0.6; Table 2) between the BNI and control groups, respectively. Almost all 90-day complications were Clavien–Dindo grade II or less (40/41, 97.5%), and there were no statistically significant differences comparing the grades of complications between groups (Table 2). The 90-day ED visit rate was higher for the BNI group (12.2% vs 6.3%, p = 0.08; Table 2), but this difference did not meet a level of statistical significance. Reasons for 90-day ED visits are reported in Table 3. There was no statistical difference between the control group and the BNI group in regard to postoperative AUASS (7.6 vs 7.7, p = 0.89), postoperative Michigan Incontinence Symptom Index (MISI) score (6.0 vs 5.1, p = 0.46), or MISI bother score (1.1 vs 0.9, p = 0.72).

Table 3.

Multivariate Logistic Regression Model Comparing Characteristics Between the Bladder Neck Incision and Control Groups

Variable	Odds ratio	95% CI	p
Age (years)	0.99	0.95–1.04	0.7
ASA			0.9
Procedure time (minutes)	0.99	0.97–1.01	0.3
Enucleation time (minutes)	0.99	0.93–1.06	0.9
Morcellation time (minutes)	1.05	0.89–1.24	0.6
Total energy (kJ)	0.99	0.89–1.24	0.2
Prostate size (cc)	0.98	0.96–0.99	0.037
OR specimen weight (g)	0.97	0.94–0.99	0.042

Multivariate analysis

Significant variables on univariate analysis (age, ASA, prostate size, procedure/enucleation/morcellation time, total energy, and OR specimen weight) were then incorporated into a multivariate logistic regression model. Only prostate size and specimen weight remained significantly different on multivariate analysis (p = 0.042 and p = 0.037, respectively; Table 3).

Discussion

In this retrospective review of 421 patients undergoing HoLEP at a high-volume academic center using Moses 2.0 laser technology, 74 patients underwent prophylactic BNI after HoLEP. The overall BNC rate was low (2/421, 0.5%), and no patients developed a BNC in the BNI (0%, 0/74) group. The BNI group on multivariate analysis was found to have smaller prostate size and OR specimen weight. Based on low rates of BNC events and our study design, we cannot imply that prophylactic BNI is protective, but a 0.0% rate of BNC in the prophylactic BNI arm (smaller prostates, lower specimen weight, and younger age) is reassuring and should prompt further prospective investigation. Patients who underwent a prophylactic BNI did not appear to be negatively impacted by the additional maneuver in any measurable way.

BNCs after HoLEP are usually diagnosed when a patient presents with a recurrence of bothersome lower urinary tract symptoms. In our experience, these men are relatively easy to identify. The patients clinically are initially satisfied by the voiding results of their HoLEP, and subsequently present months afterward with a disappointing reduction in their urinary stream. Although post-HoLEP BNCs can be treated with transurethral laser incision, preventing their development is preferred from a patient, provider, and overall system standpoint.⁴ BNI has been previously shown to prevent BNC development in patients undergoing BPH surgery.³ BNCs after TURP were hypothesized to occur because of extensive resection of the bladder neck, excessive fulguration, or exposure to excess heat energy.³ Kulb et al. reduced the BNC rate from 4.7% to 0.72% (p < 0.05) by incising the bladder neck fibers at the 6-o'clock position from the trigone to the verumontanum after TURP.³ To the best of our knowledge, although BNI has been reported after HoLEP, the outcomes and characteristics of patients undergoing prophylactic BNI have not been reported in detail.

BNC after HoLEP is a relatively uncommon complication, which makes it difficult to study. Krambeck et al. previously noted a mean specimen weight of 38.5 g in men developing BNCs and began incorporating BNI in prostate sizes <40 cc.² In another study of 1476 HoLEP patients with up to 18 years of follow-up, Ibrahim et al. reported a BNC rate of 2.1%.⁴ The authors noted that BNCs only developed in patients with prostate size <55 cc and suggested that prophylactic BNI may be beneficial for these individuals.⁴ In another study of 1216 HoLEP patients with up to 14 years of follow-up, Elkoushy et al. assessed risk factors for reoperation after HoLEP.⁷ Their group identified a BNC rate of 1.15% (n = 14). Younger age (p = 0.02) and smaller gland size (54.2 cc vs 94.6 cc, p = 0.004) were associated with BNC.⁷ On multivariate analysis, only smaller gland size remained significantly associated with BNC (odds ratio 1.84, p = 0.02). However, in a study of 127 patients undergoing HoLEP with 5-year follow-up, Enikeev et al. conflictingly did not identify an association between prostate size and BNC (p = 0.16).⁸

Similar to Elkoushy et al., we also identified that patients undergoing prophylactic BNI were younger (p = 0.0007), had a smaller prostate size (p < 0.0001), and had a lower specimen weight (p < 0.0001). On multivariate analysis, only prostate size and OR specimen weight remained significant. Both prostate size and specimen weight have been used to recommend prophylactic BNI. To better characterize the BNI group, we performed additional subgroup analyses by examining a limited cohort with prostate size <55 cc (no restriction on OR specimen weight) and another limited cohort with OR specimen weights <55 g (no size restrictions). These cutoffs were based on prior studies.^4,7

Restricting the cohort by prostate size only, resulted in similar mean prostate sizes for both groups, but OR specimen weight remained significantly different (Supplementary Table S1). Restricting the cohort by OR specimen weight only, resulted in significantly different mean prostate sizes and OR specimen weights (Supplementary Table S2). The discrepancy between the two subcohorts suggests that occasionally the preoperative prostate size may be inaccurate, which might explain why the limited prostate size cohort had similar prostate sizes, but significantly different OR specimen weights (Supplementary Table S1).

Ibrahim et al. found that BNCs occur within 2 years of follow-up and 46.7% of BNCs (14/30) occur within the first year.⁴ Enikeev et al. reported an overall BNC rate of 3.9% (5/127) and 60% of these occur within the first 3 years of follow-up (n = 3/5).⁸ Krambeck et al. reported an increasing BNC rate with longer follow-up.² However, fewer patients were available at extended follow-up periods, which may have introduced bias, as patients with postoperative concerns continue to follow-up for longer durations after surgery. The mean follow-up in our study was 14 months (range 9–20 months), which is shorter than the previously mentioned studies, but should be adequate to assess for most BNC cases. Most patients included in this study completed 1 year or longer of follow-up after HoLEP (n = 326/430, 75.8%).

Only two BNCs developed throughout the entire study period (2/421, 0.5%), which were treated with laser incision of BNC. At the time of analysis, both patients were free from BNC recurrence at 3 and 8 months after their laser BNI. No association between BNI and BNC was identified, but this could be due to limited power of this study. Interestingly, the patients who developed a BNC had a preoperative prostate size of 160 and 73 cc. Neither patient had a preoperative risk factor for BNC formation (small preoperative prostate volume, intravesical Bacillus Calmette-Guerin therapy, or prior pelvic radiation). Both patients presented with straining, urgency, and slow urinary stream ∼7.5 months after HoLEP. The results of our study suggest that factors outside of prostate size may play a role in formation of BNC after HoLEP.

We did not identify that prophylactic BNI increased 90-day complication, readmission rates, or influenced postoperative functional outcomes. The rate of ED visits was increased in the BNI group, but this did not reach a level of statistical significance. It remains unclear why the ED visit rate was higher in the BNI group. In both cohorts, hematuria was the most common reason for ED visit, and each cohort had a similar proportion of these visits (4.1% vs 2.3%, Table 4).

Table 4.

Etiologies for 90-Day Emergency Department Visits Among the Bladder Neck Incision and Control Groups

Etiology	BNI group (n = 74)	Control group (n = 347)
Neurological
Bell's Palsy	1 (1.4)
Foot drop		1 (0.3)
Stroke		1 (0.3)
Seizure	1 (1.4)
Cardiovascular
Heart failure	1 (1.4)
Respiratory		1 (0.3)
Gastrointestinal
Gastrointestinal bleed		1 (0.3)
Genitourinary
Hematuria	3 (4.1)	8 (2.3)
Urinary retention	1 (1.4)	5 (1.4)
Dysuria	1 (1.4)
Flank pain		1 (0.3)
Hematologic
Deep vein thrombosis/Pulmonary Emboli		1 (0.3)
Infectious
Urinary tract infection	1 (1.4)	3 (0.9)
Total	9 (12.1)	22 (6.3)

Percentages are shown in parentheses (proportion of the overall complications).

This study has several limitations including its retrospective design and duration of follow-up. Predictors of BNC could not be further examined due to a low rate of events (n = 2). Ultimately, a randomized controlled trial (RCT) matching patients with prostates of similar gland sizes would be required to determine if BNI at time of HoLEP definitively reduced rates of BNC. Given low rates of BNC in our contemporary study, an RCT would require multiple years of follow-up. Assuming a BNC incidence of 1.5%, to detect if BNI could reduce the BNC incidence to 0.75%, at a power of 0.80 and an alpha of 0.05, 6206 patients would be required. Designing and executing this trial would be difficult. We believe that our study provides novel insight as no prior studies have described the characteristics and outcomes of patients undergoing BNI after HoLEP in detail.

Conclusions

In this retrospective study of 421 patients who underwent HoLEP with Moses 2.0 technology, 74 patients had a prophylactic BNI performed after enucleation. Patients undergoing BNI at time of HoLEP had a smaller prostate size and lower OR specimen weight. BNI did not decrease the ability for patients to achieve same-day discharge or increase 90-day complications, ED visits, or readmission rates. At a mean follow-up of 14 months, two BNCs occurred in patients in the control group (0.6%), and no BNCs occurred in patients who underwent prophylactic BNI (0%). Further prospective studies with longer follow-up are necessary to confidently conclude that prophylactic BNI at time of HoLEP is protective against BNC. An adequately powered randomized follow-up study is likely not feasible given the low rates of BNC within this retrospective contemporary HoLEP study.

Footnotes

Authors' Contributions

N.S.D.: Data curation, formal analysis, writing. M.S.L.: Conceptualization, formal analysis, writing. M.G.: Data curation, writing—revision. M.A.A.: Conceptualization, writing—revision. J.Ha.: Data curation. J.G.: Data curation, writing—revision J.He.: Data curation. A.E.K.: Conceptualization, supervision, writing—revision.

Author Disclosure Statement

A.E.K. is a consultant for Ambu, Boston Scientific, Karl Storz, Lumenis, and Virtuoso Surgical. She is a board member of Sonomotion. M.S.L. is a consultant for Boston Scientific.

Funding Information

No funding was received for this article.

Supplementary Material

Supplementary Table S1

Supplementary Table S2

Abbreviations Used

References

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