Robot-Assisted Simple Prostatectomy for Severe Benign Prostatic Hyperplasia

Abstract

Purpose:

To validate the feasibility of robot-assisted simple retropubic prostatectomy (RSP) for men with severe benign prostatic hyperplasia (>80 g).

Patients and Methods:

Institutional Review Board approval was not sought for this series. Men were offered RSP by two surgeons with a combined experience of >350 robot-assisted radical prostatectomies. The RSP replicated previously published robotic and laparoscopic techniques. Postoperative management consisted of continuous bladder irrigation and closed suction pelvic drainage without suprapubic catheterization.

Results:

A total of nine men were treated. Indications for RSP included urinary retention in three patients, failed medical management in eight patients, and refusal of medical management in one. Average age was 68 years, mean prostate-specific antigen level was 17.4 ng/mL, and the average preoperative gland size (height-width-length volume) was 136.5 g (range 86–265 g). No operative or immediate postoperative complications occurred, and no transfusions were needed. Average blood loss, operative time, and console time were 206 mL, 183 minutes, and 147 minutes, respectively. Average pathologic adenoma volume was 112 g (range 53–220 g). Average hospitalization time and catheterization time were 32 hours and 13 days, respectively. The mean preoperative International Prostate Symptom Score was 17.8 compared with 7.77 at 6 months postoperatively (P=0.0096, 95% CI 2.83 – 17.40), with a mean follow-up time of 9.25 months. The mean Sexual Health Inventory for Men score was 12.7 preoperatively compared with 12.5 postoperatively (P=0.74, 95% confidence interval - 6.66–9.16). Persistent, severe urinary incontinence (4–6 pads per day) occurred in one patient.

Conclusions:

RSP is safe and reproducible when performed by experienced robotic surgeons and provides similar benefits to those associated with robot-assisted radical prostatectomy. In our limited experience, hemostasis was markedly decreased when compared with the open technique. Further investigation is necessary before widespread application of RSP.

Introduction

B enign prostatic hyperplasia (BPH) is a common cause of lower urinary tract symptoms (LUTS).¹ Surgical treatment for patients with BPH is reserved for those men who do not respond adequately to medical therapy or with complications of urinary retention. The gold standard surgical intervention, transurethral resection of the prostate (TURP), is limited by the size of the prostate adenoma and total resection time. For those glands that deemed too large for TURP, open simple prostatectomy (OSP), using either the suprapubic or retropubic approach, has been the preferred procedure for nearly a century.²

The shift to a minimally invasive approach to simple prostatectomy began in 2002 with the first pure laparoscopic approach.³ The first robot-assisted simple prostatectomy (RSP) was described by Sotelo and associates⁴ in 2008, and most recently (2008) a single port laparoscopic approach was reported.⁵ Transurethral laser enucleation of the prostate is a new endoscopic approach for large volume BPH that appears promising.⁶

Similar to radical prostatectomy, the pure laparoscopic approach to simple prostatectomy presents a substantial learning curve with few transferrable technical skills from OSP. The robotic platform is, therefore, the most logical minimally invasive approach to simple prostatectomy, allowing the surgeon to simulate open maneuvers. Sotelo and colleagues⁴ reported RSP in a small cohort with encouraging results. We sought to validate this experience with RSP in a community setting.

Patients and Methods

Informed consent was obtained in each case, but Institutional Review Board approval was not sought for this trial. Inclusion criteria included severe BPH (measured transrectal ultrasonography [TRUS] volume size >80 g), acute urinary retention, normal prostate cancer screen, and a contraindication to, or LUTS refractory to, BPH medical management (alpha-adrenergic blockage and/or 5 alpha-reductase inhibition). Exclusion criteria included a previous transurethral BPH procedure (ie, microwave, needle ablation, etc), TURP, pelvic radiation, LUTS related to a neurogenic bladder, previous major pelvic surgery, and a history of prostate cancer.

Procedure

All RSP procedures were performed by two experienced robotic surgeons (>350 combined robotic procedures). A five-port configuration typically used for radical prostatectomy was used initially in all cases with an additional sixth assistant port placed as needed to retract bowel or bladder. All cases were performed via an intraperitoneal approach. Bladder mobilization was performed in standard fashion. A transverse capsular incision was made in the midline with electrocautery, approximately 1 to 2.5 cm from the prostate-bladder junction.

During the first two procedures, we placed two horizontal rows of hemostatic sutures to control the Santorini plexus, as typically performed during an OSP. We attempted RSP without these sutures on the third case and found hemostasis to be adequate with pneumoperitoneum and minimal bipolar cautery. The plane between adenoma and capsule was developed thoroughly using the Maryland dissector and Endo Shears. At times, a simple suture placed through the adenoma was used to place upward traction on the adenoma using the third robotic arm, facilitating the dissection of the posterior plane. The urethra and bladder neck were incised sharply without the use of electrocautery. Care was taken not to place undue traction on the apical adenoma during the urethral dissection to minimize the change of injury to the urethra and sphincter.

Once the adenoma was removed, the interior of the prostate capsule was examined using the 30-degree down laparoscope. Inadvertent capsulotomies were closed primarily with absorbable suture. The posterior bladder neck was advanced and sutured to the posterior surface of the capsule with interrupted absorbable sutures. After adequate hemostasis was obtained, a three-way Foley catheter was placed under direct vision, and the transverse capsular incision was closed with a running absorbable suture. Continuous irrigation was initiated immediately, and the adenoma was removed using an Endo Catch bag after the robot had been undocked.

Postoperative management followed a standard prostatectomy pathway, except that the continuous bladder irrigation was titrated to off while maintaining clear efflux. This process was individualized, depending on the degree of postoperative bleeding, similar to that after a TURP. Each patient was observed for 4 to 6 hours after the irrigation was stopped before discharge to ensure adequate hemostasis. The catheter was electively left in place for 2 weeks in all patients before void trial.

International Prostate Symptom Score (IPSS) and Sexual Health Inventory for Men score were recorded preoperatively and at 6 months after surgery in a prospective fashion. In the event of acute urinary retention, the IPSS and SHIM data supplied by the patient referred to their baseline symptoms before the retention episode. Postvoid residual urine measurement was performed preoperatively and 2 weeks after surgery using ultrasonography. Clinic data and complications were recorded prospectively in a secured database. Statistical analyses were performed using GraftPad QuickCalcs software. Unpaired t test was used to analyze continuous variables.

Results

Between November 2008 and October 2009, nine men underwent RSP. Cohort and operative characteristics are seen in Table 1. Three (33%) patients experienced complete urinary retention as the indication for surgery, and eight (89%) had failed medical therapy. No major complications or deaths occurred. A single conversion to open surgery occurred in the patient with the largest gland (260 g) because of a failure to progress and excessive blood loss (500 mL). This same person is the only patient with a diagnosis of prostate cancer on the final pathology report, Gleason score 6, despite having a negative preoperative 16-core prostate biopsy. No blood transfusions or products were necessary.

Table 1.

Cohort and Operative Data

Age	68
PSA	17.4 (1.24–64)
Preoperative TRUS volume (g)	136.5 (86–265)
Pathologic volume (g)	112 (53–220)
Operative time (min)	183 (148–278)
Robot console time (min)	147 (98–228)
Estimated blood loss (mL)	206 (50–500)
Hospitalization (h)	32 (20–72)
Catheterization time (d)	13 (12–14)

PSA=prostate-specific antigen; TRUS=transrectal ultrasonography.

A minimum of 6 months of follow-up was established in all patients with a mean follow-up period of 9.25 months in the cohort. A single patient was lost to follow-up 4 months after surgery. The functional results are reviewed in Table 2. Despite the small number of patients, a statistically significant difference in IPSS scores was seen during the follow-up period. One patient experienced high-grade stress urinary incontinence (4–6 pads per day) still present 3 months postoperatively, at which time he became lost to follow-up. Two additional patients experienced minor incontinence (1 pad per day), with both men eventually achieving complete continence by the 6-month end point. One umbilical hernia occurred necessitating surgical repair.

Table 2.

Functional Results After Robot-Assisted Simple Prostatectomy

	Preoperative	3 months	6 months
IPSS	17.88 (8–31)	N/A	7.77 (0–21)	0.0096 (95% CI 2.83–17.40)
SHIM	12.7 (5–25)	N/A	12.5 (5–23)	0.74 (95% CI 6.66–9.16)
PVR	214	18.2	N/A

IPSS=International Prostate Symptom Score; SHIM=Sexual Health Inventory for Men; PVR=postvoid residual; CI=confidence interval.

We compared the operative costs for all nine RSP procedures and compared them to five OSP procedures during the same time interval performed by several surgeons at our institution. The average RSP operative cost was $5212 vs $2415 for OSP during the study period.

Discussion

OSP for BPH is a refined and efficacious surgical procedure. A contemporary multi-institutional cohort of 902 men who were treated with OSP confirms the safety of the procedure even in the hands of relatively inexperienced urology residents.⁷ The overall complication rate was 17%, mortality was 0.2%, and the improvement in the urinary flow rate was substantial at +13 mL/sec. The principal perioperative risk that is associated with the procedure is acute hemorrhage. Despite 100 years of experience and multiple described surgical techniques to reduce this risk, blood loss associated with the procedure is still quite high. Transfusion rates range from 7% to 36%, and immediate reoperation for bleeding complications is common.^7,8 Hemorrhage undoubtedly contributes to the prolonged hospitalization time that is associated with OSP, reported at 6 to 12 days on average.^7
–9

Since its inception, laparoscopic simple prostatectomy has repeatedly demonstrated a significant reduction in operative blood loss, transfusion rate, and hospitalization time compared with OSP.^3
–5,10 These improvements are theoretically caused by the venocompressive effect of the pneumoperitoneum and the need to enucleate in a slow (because of smaller instrumentation), more controlled fashion with higher use of monopolar and bipolar cautery needed to maintain surgical vision.

The ideal minimally invasive approach to simple prostatectomy has not been determined; however, the procedure is very similar to radical prostatectomy, and certain parallels can be drawn between the two. Regarding radical prostatectomy, the robot-assisted approach is well accepted to be superior to a pure laparoscopic technique with respect to surgeon learning curve, ergonomics, and ability to transfer surgical skills from an open approach. This discrepancy is even greater between the robotic platform and single port laparoscopy. These factors explain in part the expansion of robot-assisted radical prostatectomy and predict a greater role for RSP.

Sotelo and coworkers⁴ described the first experience with RSP starting in 2007. The primary surgeon had previously achieved a significant experience with pure laparoscopic simple prostatectomy before attempting RSP.¹¹ In a small cohort of well-selected men (n=7, average preoperative TRUS volume 77 g), RSP was found to be feasible, safe, and efficacious. A single complication was reported—an epigastric artery injury presumably related to port placement, necessitating the only transfusion in the group. No episodes of hemorrhage related to the enucleation were reported, however, and the average hospital stay was 1.3 days. This experience mirrors another report of RSP as well as our own.¹²

Our examination of RSP is more representative of standard urologic practice in the United States. We performed RSP in nine consecutive patients who were not eligible for TURP. No upper limit was placed on adenoma size during the preoperative evaluation when determining whether the patient was a candidate for RSP. We had achieved a modest combined robotic experience (∼350 cases over 4 years) with no previous experience with laparoscopic simple prostatectomy. Our results are encouraging and support the continued expansion of RSP into general urologic practice. The surgical times were substantially longer than previously reported for open prostatectomy, but the average blood loss (200 mL), hospitalization time (32 hours), and complication rate were superior.

Many concerns exist regarding RSP. At our institution, the cost of RSP is expectedly high compared with OSP, adding an average of $2797 to the operating charges, which does not include the initial investment cost of the robot. More importantly, we were unable to complete the procedure robotically in the case of severe prostatomegaly (260 g). The need to convert these patients to OSP and the need for large extraction incisions to remove these adenomas may limit the usefulness of this approach.¹² Lastly, transurethral laser enucleation for BPH is rapidly becoming an accepted modality for BPH, even for large adenomas. If laser enucleation demonstrates long-term efficacy and safety compared with open prostatectomy, the need for a transabdominal approach may be unnecessary.

Despite these favorable results, the applicability of our results is difficult to generalize. The limitations of our study must be considered before applying this technique. The sample size is admittedly small, and there is a risk of selection bias in the absence of randomization. To date, the combined published experience of RSP now includes 21 patients, and the results are quite consistent (Table 3).^4,12 Although we have no experience with laparoscopic simple prostatectomy, both surgeons had overcome the robot-assisted radical prostatectomy learning curve, and one is fellowship trained in endourology. Our results, therefore, may not be expected from a robotic surgeon with minimal robotic experience. Lastly, our follow-up is relatively short. Additional follow-up time might uncover late complications necessitating reoperation. A direct comparison between our experience and OSP cannot be confirmed without a randomized trial.

Table 3.

Collective Published Robot-Assisted Simple Prostatectomy Versus Open Simple Prostatectomy Data

	RSP			OSP
	Sotelo ⁴	Yuh ¹²	Sutherland	Gratzke ⁷
Patients	7	3	9	902
Adenoma volume (g)	56	301	112	84.2
Operative time (min)	205	211	183	81
Hospital stay (d) mean	1.4	1.3	1.3	11.9
Estimated blood loss (mL)	298	558	206	N/A
Transfusions	1	1	0	68 (7.5%)
Mortality	0	0	0	2
Conversion to OSP	0	1	1	N/A
Δ IPSS	−14.7		−10.1	N/A

RSP=robot-assisted simple prostatectomy; OSP=open simple prostatectomy; IPSS=International Prostate Symptom Score.

Conclusion

This study supports the safety and efficacy of RSP for severe BPH. Although limited in size, this feasibility trial appears to generate clinical results similar to those previously reported for OSP, laparoscopic, and RSP outcomes. A larger, multi-institutional examination of RSP is necessary before recommending the procedure in general practice. Real concerns remain regarding the cost of RSP relative to OSP and the ability to perform the procedure safely for massive prostatomegaly (>250 g).

Footnotes

Disclosure Statement

Dr. Weeks is a consultant for Intuitive Surgical. The other authors have no conflicts of interest to declare.

Abbreviations Used

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