Surgical treatment of benign prostatic hyperplasia: Thulium enucleation versus single‐port transvesical robotic simple prostatectomy

Abstract Objective The objective of this work is to compare our outcomes using thulium laser enucleation of prostate (ThuLEP) to the single‐port robot‐assisted simple prostatectomy (SP RASP) in the surgical management of benign prostatic hyperplasia (BPH). Methods A retrospective cohort study was conducted from January 2017 through December 2021 of men who underwent SP RASP and ThuLEP performed by a single surgeon with an enucleation experience of >300 cases and extensive robotic experience. The primary outcome was changed in International Prostate Symptom Score (IPSS) postoperatively. Secondary outcomes were operative time, length of stay (LOS), change in post‐void residuals (PVR), de novo stress‐ or urge‐urinary incontinence (SUI, UUI), and rate of complications. Results One hundred two patients underwent surgery during the study period: 33 RASP and 69 ThuLEP. There was no difference in preoperative characteristics, including age and body mass index, between both groups. Changes in IPSS scores postoperatively were not significant between SP RASP versus ThuLEP (−17 vs. −14, p = 0.2956). SP RASP had a longer operative time (180 vs. 90 min, p < 0.0001). There was no difference in LOS (0 vs. 0 days, p = 0.2904). There was no difference in change in PVR (−96 vs. −91 mL, p = 0.8504). SP RASP patients had significantly less postoperative SUI than ThuLEP (0 vs. 13 patients, p = 0.0083), while there was no difference in UUI between both groups (4 vs. 2 patients, p = 0.0843). There was no difference in 30‐day complication rate (21.2% vs. 21.7%, p = 0.9517), although there were three ThuLEP patients with Clavien–Dindo Class III or higher complication. Conclusions There was no difference in change in IPSS scores between the two groups. ThuLEP is associated with shorter postoperative catheter days and decreased operative times. Hospital LOS was equivalent. SP RASP demonstrates significantly improved continence rates. Though SP RASP is within the initial learning curve at our institution, early results demonstrate the role for this modality alongside ThuLEP in the treatment of large gland BPH.

K E Y W O R D S BPH, single-port robotic prostatectomy, thulium laser enucleation

| INTRODUCTION
Benign prostatic hyperplasia (BPH) is a common affliction in men, and prevalence increases with age with some 70% of men 61-70 years old experiencing pathological BPH. 1,2 The implications of clinical BPH can be significant, leading to decreased quality of life and well-being secondary to bothersome lower urinary tract symptoms (LUTS). [3][4][5] Ultimately, severe bladder outlet obstruction (BOO) due to BPH may lead to recurrent urinary tract infections (UTI), acute and chronic urinary retention, development of bladder stones, and upper tract deterioration, and surgical intervention may be required. 2 In the surgical management of patients with large (80-150 g) to very large (>150 g) glands, the American Urological Association (AUA) recommends consideration of simple prostatectomy (open, laparoscopic, or robotic), and laser enucleation may be considered as a prostate size-independent option as well. 6 Transurethral laser enucleation of the prostate for BPH has been performed using thulium laser enucleation of prostate (ThuLEP) and holmium laser enucleation of prostate (HoLEP) energies and has been demonstrated to be safe, cost effective, and provide durable long term functional outcomes for all size glands. [7][8][9][10][11][12] Comparison studies between the two modalities appear to demonstrate similar outcomes, and therefore choice of laser energy should be per surgeon preference. [13][14][15] Our institution prefers the use of the thulium laser for prostate enucleation, and this study will focus primarily on this energy modality.
The da Vinci single-port (SP) robotic platform (Intuitive Surgical, Sunnyvale, CA) received FDA approval for urologic use in 2018, and since that time, multiple studies have been published evaluating its utility and outcomes in major urologic procedures, including prostatectomy, ureteral reimplantation, donor nephrectomy, and transvesical operations. [16][17][18][19][20][21] Our institution has largely abandoned the use of a multiport (MP) approach to the robotic simple prostatectomy in favour of the SP system owing to its narrow profile, articulating camera, and facility in operating in a confined space. Additionally, our adoption of a novel docking system has made cystotomy needed for intravesical access less than 2 cm in size, further reducing the invasiveness of the procedure.
This study aims to compare our experience and patient functional outcomes using ThuLEP to the SP robotic-assisted simple prostatectomy (SP RASP).

| Study design and patient population
A retrospective cohort study was conducted between January 2017 through December 2021. All surgeries were performed by a single surgeon with an enucleation experience of over 300 cases along with extensive robotic experience. All patients who underwent either Thu-LEP or SP RASP for benign prostatic enlargement or urinary retention due to prostatic obstruction with a minimum of 1 month follow-up were eligible for inclusion in the study. Patients were excluded if they were lost to follow-up after surgery. This study was performed in alignment with the guidelines on Strengthening the Reporting of Observational Studies in Epidemiology (STROBE). 22 The ThuLEP and SP RASP surgeries were respectively performed in two different hospitals with similar catchment populations. This was due to the resource capabilities at each hospital. The operative teams were well trained in their respective hospitals. The surgeon operated at both hospitals with full privileges. Patients at both institutions with indications for surgery were offered choices of surgical approach and decided based on shared decision making. This study received approval from the institutional review board (IRB) from both institutions.   An 18Fr Foley is placed on the field and the bladder emptied. A flexible cystoscope is introduced per the urethra with CO 2 gas insufflation.

| Statistical analysis
A vertical 3-cm incision is made 2-3 fingerbreadths above the pubic bone as previously described. 24 The dissection is carried down to the fascia, which is then opened vertically and the rectus muscle is split bluntly, opening the retropubic space. The fat is then cleared from the bladder. The light from the cystoscope aids in the dissection. The bladder detrusor is then opened to create a mucosal diverticulum and

| Enucleation
The patient is placed in the high dorsal lithotomy position and a 24Fr sheath resectoscope with a visual obturator is used initially. The obturator is removed and a 30 lens is inserted. Bilateral ureteral orifices are identified.
A 1000-μm thulium fibre (Quanta Systems, Samarate VA, Italy) is used, with coagulation and vaporization settings adjusted for the prostate at 30 W. Settings can also be adjusted to a pulse or continuous mode, with the pulse setting providing shallower tissue penetration.
Our institution prefers an en-bloc enucleation technique. Care is taken while initially developing the enucleation plane to perform an early release of the sphincter complex to prevent traction injury. This is performed by defining the enucleation plane circumferentially proxi-

| RESULTS
A total of 103 patients underwent surgery during the study period: 34 SP RASP and 69 ThuLEP. One patient was lost to follow-up from the SP RASP group. The patient demographics and preoperative characteristics are summarized in Table 1. There were no statistical differences between the two groups. The median follow-up time for the RASP and ThuLEP cohort was 4.5 and 5.0 months, respectively (p = 0.3929). Table 2

| DISCUSSION
The transurethral resection of prostatic (TURP) adenoma has long been considered the gold standard in the treatment of BPH. However, performing bipolar or monopolar TURP when approaching large or very large glands may be challenging due to longer operative times, bleeding risk, and likelihood of incomplete resection of tissue.

Advances in technology have allowed us to revisit old techniques, that
is, open simple prostatectomy, but offer less morbid, minimally invasive, and durable responses for all size prostates. To our knowledge, this is the first study comparing outcomes between ThuLEP and the SP RASP.
While simple prostatectomy has been utilized for many years, it has evolved from an open approach to the preferred robotic approach. This minimally invasive approach decreased morbidity by reducing blood loss, hospital stay, and pain. 25 The SP robot further reduces the morbidity of the procedure. 16 Previous studies have demonstrated that both laser enucleation of the prostate and SP RASP provided durable and comparable improvement in symptoms of BPH. A recent systematic review suggested the enucleation be the preferred approach due to decreased EBL, catheter days and length of hospital stay. 26,27 However, a multicentric study evaluating outcomes of SP RASP demonstrated that mean EBL was 100 cc, catheter days were approximately 5 days, though this was variable between institutions performing this procedure. Additionally, this study noted the practice of same day discharge after SP RASP. 28 Our institution routinely performs same day surgery for these patients, and patients are discharged with minimal to no narcotics. Further analysis of these practices may be considered to address patient satisfaction and associated costs.
The utilization of the purpose-built SP access port system allows for improved use of the "floating dock technique." This provides increased working surgical space, in particular in small surgical fields with a close surgical target. 28,29 Furthermore, the access port allows for a smaller cystotomy as the size of the cystotomy need only accommodate the Alexis retractor component of the access port, and the combined width of the instruments, which enter the bladder with a combined diameter of less than 2.5 cm. Additionally, the port allows for rapid instrument exchanges, suture exchange, and specimen retrieval. We recognize that the docking of the robot and closing of the incision leads to longer operative times. The complication rates between two groups have not been statistically different; however, there were more Clavien III and higher complications in the THULEP group. These were related to postoperative bleeding associated with specimen morcellation and clot retention, which required intraoperative clot evacuation and bleeding control.
Both stem from the imprecise nature of laser enucleation and morcellation of the specimen inside of the bladder. Although the number of patients in the SP RASP group is smaller, in our experience, the patients are not brought back to the operating room for clot evacuation and bleeding control as the instruments used for SP RASP allow for a more precise enucleation plane and better directed haemostasis.
The authors acknowledge that more long-term follow-up is necessary capture any delayed complications.
Our study identified a significant difference in rates of SUI, with SP RASP showing decreased rates of incontinence. We attribute this to the ability to perform a bladder neck reconstruction, moving the urethra back in the pelvic space and better control over the apical dissection. The collapse of the fossa obtained with this reconstruction also aids in haemostasis, obviating the need for continuous bladder irrigation and therefore hospital admissions.
Our study is not without limitations. Both surgeries were performed by a single surgeon at a high-volume academic centre. We recognize that our experience may not be generalizable to the community setting. Additionally, our data do not directly compare our outcomes to those from open simple prostatectomies. The retrospective component of our study presents difficulty with variable follow-up.
We did not have a standardized follow-up protocol or pathway for either surgical cohort. Additions of flow parameters preoperatively and postoperatively would be another objective measurement to assess functional outcomes.

AUTHOR CONTRIBUTIONS
All contributions have been made with authorship in the manuscript.