Retrospective Assessment of Endoscopic Enucleation of Prostate Complications: A Single-Center Experience of More Than 1400 Patients

Abstract

Introduction:

Endoscopic enucleation of the prostate (EEP) is a safe method of treating benign prostatic hyperplasia, regardless of prostate volume and type of applied energy. To date, however, there has been no study that examines complication rates with respect to the type of applied energy. This study aims to address this problem by providing a retrospective analysis of >1400 patients who have undergone prostate enucleation.

Materials and Methods:

We performed a retrospective analysis of all patients undergoing EEP between 2013 and 2018 at a single tertiary institution. This analysis included patients who had undergone one of three forms of EEP: holmium laser enucleation of the prostate (HoLEP), thulium fiber laser enucleation of the prostate (ThuFLEP), or monopolar enucleation of the prostate (MEP). We compared intraoperative and early postoperative complications, as well as complications at 3 and 6 months follow-up.

Results:

A total of 1413 patients were included in this study; 36% patients underwent HoLEP, 57.5% had ThuFLEP, and 6.5% MEP. The most frequent complication in the early postoperative period was a mild fever (2.76% of the cases). The morcellation was delayed to a separate stage because of intensive hemorrhaging in 1.4% of the cases. Bladder tamponade was found in 1.1% of the cases. We found no correlation between complication rate and either prostate volume or energy source. Stress urinary incontinence was found in 3.9% of patients at 3 months and in only 1.4% of patients at 6 months after the operation. Urethral stricture at 6 months after the surgery was found in 1.4% of patients, whereas bladder neck sclerosis was found in only 0.9% of these cases. No significant difference was observed between these complication frequencies and any preoperative factors or energy source.

Conclusions:

All EEP types are safe with equal rates of complications intraoperatively, postoperatively, and at 6 months follow-up.

Introduction

Simple prostatectomies (SPs) and transurethral resections of the prostate (TURPs) have conventionally and historically been the most common procedures performed for the treatment of benign prostatic hyperplasia (BPH).¹ However, recent studies have discovered that both SP and TURP procedures have been linked with increased rates of perioperative and postoperative morbidity, especially with prostates >100 cc.² In response to these findings, there has been a gradual shift to employ endoscopic enucleation of the prostate (EEP) with varying laser energies as a far more minimally invasive alternative to traditional surgeries.

In 1998, the first functional EEP was introduced in the form of holmium laser enucleation of the prostate (HoLEP). It demonstrated similar surgical outcomes as traditional SP and TURP procedures, with lower complication rates for any prostate volume.^3,4 Since then, EEPs have only become more and more commonplace.

Despite the growing popularity of EEPs, the European Association of Urologists, as recently as 2019, has continued to support TURP as the “standard of surgical treatment” for patients with LUTS and prostate volumes up to 80 cm.^1,3 However, other institutions, such as the American Urological Association, have started to recommend and encourage laser enucleation regardless of prostate gland volume.⁶

As novel forms of EEP are developed, such as thulium fiber laser enucleation of the prostate (ThuFLEP), there is a need to explore the feasibility and efficacy of EEP with respect to complication rates.^2,3,8 To our best knowledge, there has not been a study that directly compares the results of more than two EEP methods on a large group of patients. It is the aim of this study to address this gap in knowledge and analyze the frequency of major complications following various EEP methods, including HoLEP, ThuFLEP, and monopolar enucleation of the prostate (MEP).

Materials and Methods

Patient assessment

We performed a retrospective review of prospectively maintained database of three types of endoscopic enucleations (HoLEP, ThuFLEP, and MEP) in our clinic between 2013 and 2018 by four experienced surgeons. The first 50 cases of each operating surgeon were not included in the study to exclude complications that could have resulted during the learning curve. The preoperative examination included a prostate-specific antigen (PSA) test, uroflowmetry with ultrasound measurement of residual urine volume, and transrectal ultrasound imaging (TRUS). All patients completed International Prostate Symptom Score (IPSS) and quality of life (QOL) questionnaires.

Study outcomes

The primary objective was to analyze and compare each operation's relative safety by estimating intraoperative and early postoperative complication rates. Complications were graded according to Clavien–Dindo classification.⁹

Secondarily, we assessed patient complications rates both at 3 and 6 months following their procedures.

To determine if a patient's prostate gland volume influences their rate of complication, we looked at intraoperative and early postoperative complications between two groups: patients with prostate volumes ranging from 30 to 79 cm³ and with >80 cm³. In addition, we also examined the age-specific frequency of stress urinary incontinence by comparing patients who were <65 years to those >65 years.

Surgical technique

HoLEP was performed using the 100-Watt Versapulse holmium laser (Lumenis, USA), a 120-Watt FiberLase U1 thulium fiber laser (NTO IRE-Polus, Russia) was used for ThuFLEP, and a monopolar instrument with a generator (ValleyLab, USA) was used for MEP. It is worth mentioning that thulium fiber laser differs from Thulium:YAG laser (ThuLEP procedure). Thulium fiber laser has another wavelength (1940 nm vs 2040 of Thulium:YAG) resulting in a smaller tissue penetration depth (0.15 vs 0.2–0.4 of Thulium:YAG).⁴ Its advances over other solid-state lasers were previously carefully described.⁵ Our surgical techniques for all procedures have been previously described.¹⁰

Follow-up

All patients were seen in the clinic at 6-month postoperative follow-up evaluation, which included urinalysis and urine culture, IPSS questionnaire, uroflowmetry, and TRUS. Those patients who did not show up for their follow-up appointment were excluded from the study. Patients complaining of difficulty urinating underwent retrograde and miction urethrography.

Statistical analysis

Mean and standard deviation values were calculated for variables. If the mean proved to be uninformative, median and quartile distributions were also calculated. The statistical significance between the samples was tested using a Pearson's chi-squared test with Fisher correction, when necessary. We performed a multifactor logistic regression analysis to determine any connections between preoperative factors and complication rates. A p-value of 0.05 was chosen as a threshold for statistical significance. All statistical analysis were performed using the SPSS Statistics, version 23.0 software (IBM, Armonk, NY).

Results

A total of 2000 patients who underwent EEP were identified during the study period. Of these, 200 patients (first 50 for each surgeon) were excluded because the surgeons were not at their learning curve plateau. Additional 387 patients were excluded because of unavailability for 3- and 6-month follow-ups. Remaining 1413 patients who met the inclusion criteria and completed the study follow-up procedures were included in the study. A total of 509 patients underwent HoLEP, 812 ThuFLEP, and 92 MEP. Table 1 demonstrates the demographic and clinical characteristics of patients. The mean age of our patients was 66.9 ± 7.6 years. The mean prostate volume in the cohort was 87 ± 41 cm³ (range 30–320 cm³). In total 696 (49.3%) patients had prostate volume of <80 cm³ and 717 (50.7%) patients had >80 cm³. To assess possible connection association with age, we compare complication rates in two groups: 626 (44.3%) patients aged ≤65 years and 787 (55.7%) patients >65 years.

Table 1.

The Group's Baseline Characteristics

Characteristics	HoLEP (n = 509)	ThuFLEP (n = 812)	MEP (n = 92)	p
Age, years	66.5 ± 7.7	67 ± 7.6	67.5 ± 6.6	0.2
PSA, ng/cc	4.5 ± 3.1	5.2 ± 5	3.8 ± 2.2	0.1
Prostate volume, cm³	91 ± 44	86 ± 40	68 ± 23	0.02
Residual urine volume, cc	70.8 ± 28.8	74 ± 20.7	63.8 ± 26.4	0.01
Q_max, mL/s	7.7 ± 1.8	10 ± 2.7	8.2 ± 2	0.02
IPSS	22 ± 1.2	23.1 ± 1.8	22.6 ± 2.1	0.01
QOL	4.05 ± 0.88	4.03 ± 0.83	4.02 ± 0.84	0.1

The data are presented as mean ± standard deviation.

HoLEP = holmium laser enucleation of the prostate; IPSS = International Prostate Symptom Score; MEP = monopolar enucleation of the prostate; PSA = prostate-specific antigen; QOL = quality of life; ThuFLEP = thulium fiber laser enucleation of the prostate.

All the patients demonstrated decreased uroflowmetry parameters (Q_max 9.1 ± 2.6 mL/s) and expressed lower urinary tract symptoms (IPSS score was 22.7 ± 1.7, QOL score was 4 ± 0.85). The mean PSA level was 4.9 ± 4.4 ng/cc. The baseline surgery characteristics are listed in Table 2.

Table 2.

The Baseline Surgery Characteristics

Characteristics	HoLEP (n = 509)	ThuFLEP (n = 812)	MEP (n = 92)	p
Total surgery time, minutes	76 ± 35	67 ± 29	59 ± 27	<0.001
Enucleated tissue weight, g	75 ± 36	69 ± 33	55 ± 21	<0.001
Time of catheterization, days	1.4 ± 0.6	1.8 ± 0.8	2.3 ± 1.4	<0.001
Time of hospital stay, days	3.4 ± 0.6	3.8 ± 1.0	4.2 ± 2.0	<0.001
PSA after surgery, ng/cc	1.0 ± 0.3	1.0 ± 0.3	1.0 ± 0.3	0.915
Residual urine after surgery, ml	17.2 ± 12.2	11.9 ± 9.3	14.1 ± 9.5	0.121
Q_max after surgery, mL/s	20.6 ± 4.5	22.2 ± 3.2	18.9 ± 4.1	0.066
IPSS after surgery	5 ± 2	5 ± 2	5.1 ± 1.9	0.773
QOL after surgery	1.8 ± 0.7	1.6 ± 0.6	1.7 ± 0.6	0.074

Intraoperative and early-postoperative complications

The first type of Clavien–Dindo grade 1 complication was ureteral orifice injury in 0.5% of the cases (three cases in HoLEP, four cases in ThuFLEP, and none in MEP). In practice, this situation normally requires upper urinary tract stenting. However, we demonstrated in our previous article¹¹ that with laser enucleation, one can avoid stenting, provided there is careful upper urinary tract ultrasound monitoring (Table 3).

Table 3.

The Frequency of Major Complications After Prostate Enucleation

Clavien–Dindo grade	Complication	HoLEP (n = 509), %	ThuFLEP (n = 812), %	MEP (n = 92), %	p
Early postoperative complications
I	Ureteral orifice injury	0.5	0.5	—	0.63
I	Bladder mucous injury	2.36	1.35	3.3	0.53
II	Fever	2.95	2.46	4.3	0.56
II	Delayed morcellation	2	1.2	2.2	0.27
IIIa	Bladder tamponade (Bleeding)	2.2	2	4.3	0.26
IIIa	TURP syndrome	—	—	1.1	0.011

Complication	Time	HoLEP, %	ThuFLEP, %	MEP, %	p
Late postoperative complications
Stress urinary incontinence, grade 1	3 Months	3.9	3.5	4.3	0.687
Stress urinary incontinence, grade 1	6 Months	1.7	1.1	3.1	0.116
Urethral stricture	6 Months	1.8	1.1	2.2	0.495
Bladder neck sclerosis	6 Months	1	0.7	2.2	0.37

TURP = transurethral resection of the prostate.

The second was superficial bladder mucous injury during morcellation, which occurred in 12 (2.36%) cases of HoLEP, 11 (1.35%) cases of ThuFLEP, and 3 (3.3%) cases of MEP, p = 0.53. It required no specific actions except vessel coagulation in case of bleeding. Large BPH volume did not increase the risk of this complication significantly. In group with prostate volumes <80 cm³ it occurred in 1.6%, in group with larger volume in 2.1%. We used two morcellators: Piranha from Richard Wolf and VersaCut from Lumenis. No connection between the rate of superficial injury and morcellator type was observed.

The Clavien–Dindo grade 2 most frequent complication in the early postoperative period was a fever of >38°C accompanied by leukocytosis in 2.76% of cases (2.95% of the cases after HoLEP, 2.46% of the cases after ThuFLEP, 4.3% of the cases after MEP, p = 0.56) (Table 3). In the group with prostate volumes <80 cm³, fever was only found in 3% of the patients after any type of enucleation. In patients with larger prostate volumes, fever was revealed in only 2.5% of the patients; however, the differences were still insignificant (p = 0.3).

Another common grade 2 complication was the necessity to delay morcellation because of intensive intraoperative hemorrhage and consequent unsatisfactory observation. This complication was found in 1.4% of cases (2% in HoLEP, 1.2% in ThuFLEP, 2.2% in MEP, p = 0.27) and it was found that prostate volume did not produce any significant effect on complication frequency: 1% in patients with prostate volume <80 cm³ vs 1.8% in patients with larger glands (p = 0.09) (Table 4).

Table 4.

The Frequency of Major Intraoperative and Early Postoperative Complications Depending on the Prostate Volume

Complications	Prostate volume 30–79 cm³, %	Prostate volume 80–320 cm³, %	p
Fever	3	2.5	0.3
Delayed morcellation	1	1.8	0.09
Bladder tamponade	1	1.1	0.4
Ureteral orifice injury	0.4	0.6	0.4
Bladder mucous injury	1.6	2.1	0.1
Stress urinary incontinence (<3 months)	4.5	3.3	0.13
Urethral stricture	1.4	1.3	0.4
Bladder neck sclerosis	0.9	1	0.4

The most frequently observed Clavien–Dindo grade 3 complication was bladder tamponade, as EEPs often require endoscopic revision and vessel coagulation. It was found in 1.1% of cases, with only one patient requiring a blood transfusion. The complication frequency of bladder tamponades was 2.2% after HoLEP, 2.0% after ThuFLEP, and 4.3%, after MEP (p = 0.267) (Table 3). In addition, the tamponade frequency was 2% and 2.9% in the patients with BPH volumes <80 and >80 cm³, respectively (p = 0.4).

The only one case of TURP syndrome, which was Clavien–Dindo grade 3 complication, occurred in the MEP group. Because of relatively small size of this group, this case appeared to be statistically significant, p = 0.01. This patient was transferred and managed conservatively in the intensive care unit.

All major intraoperative and early postoperative complications are listed in Table 3. Multilogistic regression showed several predominantly insignificant connections (Table 5), mostly with patients' age.

Table 5.

Multilogistic Regression Model with Potential Factors Effecting Complications (Only Significant Connections Included)

Predictor	Regression coefficient (β)	Mean-square error	Wald, χ²	Significance (p)	OR	95% CI for OR
Predictor	Regression coefficient (β)	Mean-square error	Wald, χ²	Significance (p)	OR	Low	High
Bladder neck sclerosis
Age, years	−0.070	0.004	270,682	<0.001	0.814	0.795	0.834
Urethral stricture
Age, years	−0.064	0.003	335,662	<0.001	0.938	0.932	0.945
Fever
Age, years	−0.035	0.008	19,237	0.3	0.966	0.951	0.981
Residual urine, mL	−0.017	0.008	5028	0.06	0.983	0.968	0.998
Stress urinary incontinence
Age, years	−0.034	0.011	8791	0.07	1.134	0.997	1.183
Q_max, mL/s	−0.234	0.093	6251	0.08	0.792	0.659	0.951
Bladder tamponade
Age, years	−0.038	0.013	8886	0.3	0.962	0.938	1.024
Q_max, mL/s	−0.227	0.105	4720	0.4	0.797	0.649	0.978
Bladder damage
Age, years	−0.086	0.007	152,429	0.06	1.201	0.906	1.401
Delayed morcellation
Age, years	−0.066	0.004	310,016	0.06	0.936	0.929	0.943

CI = confidence interval; OR = odds ratio.

Complications at 3 and 6 months' follow-up

We found that postoperative urine incontinence is transient: after 3 months stress urine incontinence was found in 3.9% of patients and after 6 months in only 1.4% of patients (Table 3). We found no correlation between the frequency of this complication, any preoperative factors, and operation type. Similarly, the rate of a late urethral stricture complication was 1.4%, whereas the rate of bladder neck sclerosis was 0.9%. The age-specific frequencies of these complications are listed in Table 6, and the enucleation-specific complication frequencies are shown in Table 3. We found no significant correlation either between the age and the frequency of these complications or between enucleation groups with respect to their different complication frequencies.

Table 6.

The Frequency of Late Postoperative Complications Depending on Patient Age

Complications	Age ≤65 years, %	Age >65 years, %	p
Stress urinary incontinence after 3 months	3.4	4.3	0.2
Urethral stricture	1.4	1.4	0.5
Bladder neck sclerosis	1.1	0.8	0.2

Finally, it is important to note that we did not observe any Clavien–Dindo grades 4 and 5 complications (especially with respect to urosepsis), with the exception of a TURP syndrome case in the MEP group.

Discussion

Our study profiles some of the most common postoperative complications that may arise because of an EEP. According to current publications, EEP is not inferior to the standard TURP procedure used to treat BPH,^6

–9 but it is even more effective than TURP in its ability to remove adenomatous tissue.¹⁰ EEP is also advantageous in treating recurrent prostate hyperplasia, as repeated operations have not been found to be associated with serious technical difficulties.¹¹

All three groups (HoLEP, ThuFLEP, and MEP) of patients in our study had no significant difference in preoperative characteristics (Table 1) except BPH volume. Mean prostate volume in the MEP group (68 ± 23 cm³) is slightly less than in the other two groups (HoLEP 91 ± 44 cm³, ThuFLEP 86 ± 40 cm³). During one of the first MEP procedures we performed, we encountered an incident of TURP syndrome because of the nonsaline irrigation. For this reason, we decided to select patients with smaller prostate volumes to MEP for following procedures. This may be an essential limitation of this procedure, but we cannot make strong conclusions because of relatively small size of the MEP group. Laser enucleation is usually performed with a saline, which makes this complication impossible.

We observed that there were no clear and obvious risk factors for the development of complications across our patient cohorts. Previous studies that examined potential operative risk factors were not able to conclusively determine if these issues can contribute to the onset of any of these observed complications.¹⁸

We believe that a patient's prostate volume does not correlate with their risk of complications for EEP in general, which was confirmed in multivariable analysis (Table 5). Nevertheless, because of the relatively small size of MEP group and less BPH volume there, we cannot confidently extrapolate our conclusion to this particular group. Further research is necessary for the evaluation of this complication. We found across all complications no statistical significance between patients with prostate volumes 30 to 79 cm³ and those with volumes 80 to 320 cm³ (Table 4). We use 80 cm³ as a cutoff for BPH volume because, according to EAU Guidelines, this size BPH is considered “large” and it is strongly recommended to perform EEP for such patients.¹² This finding adds credence to the fact that EEP can be performed safely, regardless of prostate volume. Our results are similar to those noted in previous studies, namely Rao et al. (2014)¹⁹ and Shah et al.^20,23

Nowadays, we can see that as life expectancy increases, so does the prevalence of BPH.¹³ We suppose that it may result in an increase of surgical intervention rate in this age group. According to the World Health Organization, individuals <65 years are considered to be young.²² With this in mind, we decided to compare the complication rates between patients who are <65 years to those >65 years. Like with prostate volumes, we were similarly unable to find any significant connections between age and complication rates, as we did not observe any significant difference in either urinary incontinence (3.4% in patients <65 years and 4.3% in elder patients, p = 0.2), urethral stricture rate (1.4% vs 1.4%, p = 0.5), or bladder neck sclerosis (1.1% vs 0.8%, p = 0.2) (Table 6). Based on this data, we can confidently say that EEP procedures can be safely performed on patients, regardless of their age.

Furthermore, a comparison of laser and electric techniques revealed no significant difference in the frequency of bleeding (HoLEP 2.2%, ThuFLEP 2%, MEP 4.3%, p = 0.26), infections (fever) (HoLEP 2.95%, ThuFLEP 2.46%, MEP 4.3%, p = 0.56), and other complications (Table 3). Previous studies have pointed to various reasons for why specific forms of energy types (laser or electric) may influence complications in different ways. For example, Baldini et al.⁸ found that, in comparison with SP, HoLEP reduced the duration of catheterization and blood loss. The authors speculated that this improvement could be attributed to the active application of energy during a laser operation as opposed to mechanical enucleation in operation with monopolar instruments.¹⁴ In contrast, other studies have suggested that electrical instrument enucleation is associated with smaller blood loss caused by deeper coagulation.¹⁵

Extensive intraoperative blood loss may play a significant and contributory role in the onset of specific EEP complications, such as delayed morcellation. We hypothesize that the overwhelming majority of these complications result from prostatic venous plexus injuries. In this case, the primary hemostatic technique is the insertion and inflation of a urinary catheter rather than coagulation. The surgeons in our clinic perform delayed morcellation 48 hours after enucleation. This time is enough for stable hemostasis. We hypothesize that, in the liquid medium of the bladder, the adenomatous tissue hydrates positively affecting the delayed morcellation rate.

Bladder injury is a possible complication of BPH tissue morcellation. To decrease its risk, it is essential to gain good visibility by thorough hemostasis and fill up the bladder. Superficial trauma is not dangerous, but full-thickness injury of bladder wall may require open surgery to manage the bleeding and close the perforation.²³

Several past studies also examining EEP complications suggest that patients' age, prostate volume,^16,17 operation duration, and blood loss volume^18,19 are all possible urinary incontinence predictors. In our study, however, we did not find such relationships with urinary incontinence. We observed no visible difference in urinary continence both immediately after catheter removal and after 6 months (Tables 3, 4, 6).

Other studies have also reported a low frequency of urethral stricture and bladder neck sclerosis, similar to the findings from this study. Elzayat et al.²⁰ found these complications in 1.7% and 0.8%, respectively. The risk of these complications was also found to be higher in repeated operations.²¹

Despite a somewhat limited follow-up period (6 months), our conclusions do not contradict those made in Alkan et al.,²² which exclusively examines holmium laser enucleations but with a substantially more extended follow-up period (3 years). In our study, we found no specific complications or increased frequency of existing complications in the late postoperative period, as this period is usually characterized by sustainable positive results after an operation.

Although this research is retrospective, it is based on a prospective database with consecutive series of operations. The other limitation worth mentioning is small number of patients in MEP group comparing with group of laser surgery. Also, patients in MEP group had smaller glands, but as the data demonstrated, prostate volume does not significantly influence the complications rate. All EEP procedures were performed by four surgeons, which may introduce bias in study results, but we believe this supports the generalization of the data. In addition, we compared the results among the surgeons and found no significant differences. There is no group with bipolar EEP in our study; the electric instruments used for EEP were monopolar because this technique had been studied in our clinic then.

Conclusions

We found no significant difference between HoLEP, ThuFLEP, and MEP regarding complications rate at intraoperative early postoperative period, as well as 6 months after surgery. All complications were found to be below Clavien–Dindo grade IIIb; the rate of the complications was low. Prostate volume and patient's age also did not affect complications rate. Thus, all these three types of EEP can be performed safely to all patients regardless BPH volume and age.

Footnotes

Author Disclosure Statement

No competing financial interests exist.

Funding Information

No funding was received for this article.

Abbreviations Used

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