Extraperitoneal vs Transperitoneal Robot-Assisted Radical Prostatectomy in the Setting of Prior Abdominal or Pelvic Surgery

Abstract

Introduction:

During robot-assisted radical prostatectomy (RARP), the prostate may be approached extraperiteoneally (extraperitoneal robot-assisted radical prostatectomy [eRARP]) or transperitoneally (transperitoneal robot-assisted radical prostatectomy [tRARP]). The former avoids the abdominal cavity, which might be of benefit in patients who have had prior abdominal or pelvic surgery (PAPS). Our objective was to compare the outcomes of patients with PAPS undergoing either technique.

Methods:

A retrospective review of patients treated with RARP from July 1, 2003 to December 31, 2014 with a minimum follow-up of 3 months was undertaken. Of 2927 patients, 620 were identified as having undergone RARP (without concomitant unrelated procedures) and PAPS (excluding patients with prior inguinal hernia repair with mesh or unclear surgical histories) for prostate adenocarcinoma without prior pelvic radiotherapy. Of these, 340 patients underwent eRARP and 280 patients underwent tRARP.

Results:

Patients in the eRARP group were younger (61.04 years vs 62.32, p = 0.02), had a higher body mass index (29.65 vs 28.98, p = 0.09), lower American Society of Anesthesiologists scores (p = 0.03), and lower D'Amico risk classification disease (p < 0.0001). The two groups had similar rates of 1, 2, and >2 PAPS. On univariate analysis, the eRARP group had lower operative time (188.96 minutes vs 197.92 minutes, p = 0.003), extensive lysis of adhesions (0.9% vs 14.3%, p < 0.0001), length of hospital stay (LOS) (1.13 days ±0.45 vs 1.33 day ±1.08, p = 0.003), and higher estimated blood loss (210.74 mL vs 190.79 mL, p = 0.06). The eRARP group had a lower rate of gastrointestinal complications (0% vs 3.21%, p = 0.0007), a trend toward lower early post-operative complications (8.53% vs 12.86%, p = 0.08), and lower overall complications (9.41% vs 15%, p = 0.03). In regression analysis with model selection, only LOS was lower in the eRARP group (p = 0.02).

Conclusions:

Both methods are safe in patients with prior abdominal surgeries. A lower incidence of gastrointestinal complications and a shorter length of stay were noted in the extraperitoneal cohort.

Introduction

Prostate cancer is the most commonly diagnosed non-cutaneous malignancy among men in North America,¹ and level 1 evidence has demonstrated that radical prostatectomy prolongs survival compared with watchful waiting.² Robot-assisted radical prostatectomy (RARP) has been shown to improve on the traditional open approach by decreasing postoperative pain, hospital stay, 90-day hospital readmission rates, blood loss, and blood transfusion rates.^3

–6 Though controversial, newer systematic reviews and meta-analyses have shown better 12-month continence rates,⁷ 12-month potency rates,⁸ and bladder neck contracture rates⁹ for RARP compared with open surgery.

Until the advent of minimally invasive surgery, the standard approach to the prostate was extraperitoneal, accessing it directly via the space of Retzius or the perineum. In contrast, laparoscopic and RARP are routinely performed by using both extraperitoneal and transperitoneal approaches. The latter approach is preferred by most surgeons, because it offers a larger working space, and the anatomy is more easily recognizable. It is a more commonly taught approach in North American Urology training programs, with a much larger number of related publications available on its uses. The extraperitoneal approach has been proposed as preferable in specific situations, due to certain favorable perioperative parameters¹⁰

One theoretical benefit of avoiding entry into the peritoneal cavity is easier access in patients with prior abdominal surgeries. Lysis of adhesions, which may be required in this setting, is avoided. Ileus resulting from bowel manipulation is not encountered with the extraperitoneal approach. The intraabdominal cavity is left unaltered, eliminating the risk of future adhesions that can make further surgeries more difficult and place the patient at risk for bowel obstruction. Only mild Trandelenburg positioning is used with extraperitoneal robot-assisted radical prostatectomy (eRARP), which may also be beneficial in the obese patient or in those with obstructive pulmonary disease.¹¹

Despite this, there have no peer-reviewed articles that can corroborate the claim that an extraperitoneal approach is superior in patients who have had prior abdominal or pelvic surgery (PAPS). Our group aimed at exploring this by analyzing a retrospective cohort of patients who have had PAPS and have subsequently undergone eRARP or transperitoneal robot-assisted radical prostatectomy (tRARP). Our primary aim was to compare peri- and post-operative outcomes between the groups. Patient and disease characteristics were also compared. Regression analysis was then used to adjust for the confounding effects of covariates.

Materials and Methods

All patients who underwent RARP from July 1, 2003 to December 31, 2014 by a single surgeon (J.V.J.) and had a minimum of 3 months of follow-up were evaluated. Data were prospectively maintained in a quality assurance database. Institutional Research Subjects Review Board approval was obtained before the initiation of data collection or analysis. For the majority of cases, information related to a patient's prior medical or surgical history was taken in an outpatient clinical setting by a healthcare provider or via a self-administered questionnaire. In cases where surgical details were ambiguous or unknown, subjects, and in some cases their primary care physicians, were contacted by telephone or a faxed questionnaire.

Only patients who underwent RARP for needle biopsy-proven adenocarcinoma were included in the analysis. Biopsies performed at outside institutions underwent a pathological review by dedicated genitourinary pathologists at our institution. Patients with prior inguinal hernia repair with mesh (IHRm), prior radiotherapy, or ambiguous surgical details were excluded from this study. Patients with a surgical history of inguinal hernia repair (IHR) without mesh were included, but patients with prior inguinal orchiectomy/orchidopexy were not. Individual patients' pre-RARP surgical histories were not necessarily verified by referencing original operative records.

Patient demographics, disease characteristics, and peri- and post-operative outcomes were compared. Complications were compared as individual events, as number of patients who had any complications, and with the Clavien–Dindo classification. If greater than one Clavien–Dindo complication occurred, the highest score was used. Complication type was divided into peri-operative, early, and late complications based on standard clinical definitions and not by rigid time cutoff points.

Trocar placement

Trocar access during tRARP begins with insufflation of the abdomen by using a Veress needle. A 12 mm assistant trocar is placed 8–10 cm cephalad to the right anterior superior iliac spine. An 8 mm camera trocar is placed just below the umbilicus, and three other 8 mm working trocars are placed in a “W” configuration, taking care not to injure the inferior epigastric vessels. An additional 5 mm assistant trocar is placed 4 cm lateral and cephalad to the camera trocar. All trocars are placed under direct vision.

In the case of a patient with PAPS, access is gained by using a 5 mm trocar at one of the marked sites farthest from the area of anticipated adhesions by using a visual obturator. This is later replaced with an 8 mm robotic trocar after all other trocars have been inserted. This 5 mm trocar may be placed in the left upper quadrant when extensive or diffuse adhesions are anticipated. Adhesions are lysed laparoscopically before docking.

Our technique for obtaining access during eRARP has been previously published.¹² Briefly, a 2.5 cm paraumbilical incision is made to the level of the anterior rectus sheath. A 1 cm incision is made through this, and the rectus muscle fibers are pushed laterally. A balloon dilator is advanced superficial to the posterior rectus sheath to the pubic symphysis. The space is insufflated under direct vision by using the balloon and the beveled tip of the trocar to create the space laterally. All other trocars are placed under direct vision as in the tRARP approach. No modifications are necessary in the patient with PAPS. When a prior midline scar extends to the pubic symphysis, the extraperitoneal space may have been previously violated, so extra care is taken to avoid inadvertent peritoneotomies.

Statistical analysis

Continuous measurements were compared by using the two-sample t-test. Categorical variables were compared by using Fisher's exact test or Pearson's chi-squared test where appropriate. Regression analysis with model selection was used to study the effects of covariates on operative (operating room [OR]) time, estimated blood loss (EBL), time to catheter removal (TCR), and complications. Poisson regression was used to study the outcomes of count data, logistic regression for binary outcomes, and linear regression for continuous outcomes. Statistical analyses were implemented with SAS 9.4 (SAS Institute, Inc., Cary, NC).

Results

Two thousand nine hundred twenty-seven patients who underwent RARP's for localized prostate cancer with a minimum of 3 months follow-up were reviewed. Patients were excluded for the following reasons: prior pelvic radiotherapy,⁸ no history of pre-RARP abdominal or pelvic surgery (1850), known history of IHRm (297), unconfirmed history of IHRm (138), history of IHRm but mesh explanted before RARP (1), IHR concomitant with RARP,¹² and prostate cancer subtype not adenocarcinoma (1). The final series comprised 620 patients, of whom 340 underwent eRARP and 280 underwent tRARP.

Patient demographics and disease characteristics are shown in Table 1. Compared with the tRARP group, patients in the eRARP group were younger (61.04 ± 6.78 years vs 62.32 ± 6.61 years, p = 0.02), had a higher body mass index (BMI; 29.65 ± 4.74 vs 28.98 ± 4.89, p = 0.09), and lower American Society of Anesthesiologists (ASA) scores (p = 0.03). They also had more favorable disease characteristics as measured by lower pre-RARP PSA (5.95 ± 3.3 vs 6.91 ± 4.63, p = 0.004), lower prostate biopsy Gleason sum score (p < 0.0001), and lower clinical T stage (p = 0.0004), which translated to lower D'Amico risk classification (p < 0.0001).

Table 1.

Patient and Disease Characteristics

	eRARP	tRARP	p-Value
Age, years (mean ± SD)	61.04 ± 6.78	62.32 ± 6.61	0.02
BMI (mean ± SD)	29.65 ± 4.74	28.98 ± 4.89	0.09
ASA score (n/%)			0.03
1	22 (6.49)	8 (2.88)
2	260 (76.7)	205 (73.74)
3	56 (16.52)	63 (22.66)
4	1 (0.29)	2 (0.72)
Pre-RARP PSA (mean ± SD)	5.95 ± 3.3	6.91 ± 4.63	0.004
Prostate biopsy Gleason sum (n/%)			<0.0001
5 and 6	225 (66.2)	89 (31.8)
7	102 (30.0)	153 (54.6)
8	11 (3.2)	30 (10.7)
9 and 10	2 (0.6)	8 (2.9)
Clinical T stage (n/%)			0.0004
T1a	0 (0)	1 (0.36)
T1c	265 (77.94)	189 (67.5)
T2a	61 (17.94)	57 (20.36)
T2b	5 (1.47)	22 (7.86)
T2c	9 (2.65)	10 (3.57)
T3a	0 (0)	1 (0.36)
D'Amico risk classification, worse (n/%)			<0.0001
Low	205 (60.47)	76 (27.14)
Intermediate	109 (32.15)	151 (53.93)
High	25 (7.37)	53 (18.93)

Continuous measurements: age, BMI, pre-operative PSA (two-sample t-test).

Categorical variables: ASA, prostate biopsy worse Gleason sum score, and Clinical T stage (Fisher's exact test); D'Amico risk classification (Pearson's chi-square test).

Frequency missing: ASA (3), D'Amico (1).

ASA = American Society of Anesthesiologists; BMI = body mass index; eRARP = extraperitoneal robot-assisted radical prostatectomy; PSA = prostate specific antigen; RARP = robot-assisted radical prostatectomy; SD = standard deviation; tRARP = transperitoneal robot-assisted radical prostatectomy.

Individual PAPS and counts of PAPS per patient are shown in Table 2. Among 17 different types of procedures, differences were noted only in prior colorectal surgery (2.65% vs 9.29%, p = 0.0004) and IHR without mesh (12.6% vs 22.9%, p = 0.0009) for the tRARP vs the eRARP groups, respectively. No differences were noted between the groups with respect to patients who had undergone 1, 2, or >2 pre-RARP procedures.

Table 2.

Pre-Robot-Assisted Radical Prostatectomy Abdominal and Pelvic Procedures—Individual Counts

	eRARP (n = 340)	tRARP (n = 280)	p-Value
PAPS type (n/%)
Abdominal wall hernia	57 (16.7)	39 (13.9)	0.35^*
Adrenalectomy	1 (0.29)	1 (0.36)	0.59
Appendectomy	155 (45.6)	126 (45.0)	1.00^*
Bladder surgery	0 (0)	3 (1.07)	0.09
Cholecystectomy	81 (23.8)	54 (19.3)	0.20^*
Colorectal surgery	9 (2.65)	26 (9.29)	0.0004^*
Creation/reversal of stoma	2 (0.59)	1 (0.36)	1.00
Exploratory laparotomy	11 (3.24)	5 (1.79)	0.32^*
Gastric surgery	13 (3.82)	11 (3.93)	1.00^*
Hepatobiliary and Pancreatic surgery	4 (1.18)	2 (0.71)	0.70
Inguinal hernia without mesh	43 (12.6)	64 (22.9)	0.0009^*
Liver transplant	3 (8.82)	0 (0)	0.27
Native renal surgery	16 (4.71)	8 (2.86)	0.30^*
Renal transplant	1 (2.94)	0 (0)	1.00
Small bowel surgery	2 (5.88)	0 (0)	0.50
Splenectomy	7 (2.06)	1 (0.36)	0.08
Ureteral/renal pelvis Surgery	5 (1.47)	2 (0.71)	0.46
Total (n/mean)	410 (1.21)	343 (1.23)	0.10^**
PAPS, count per patient (n/%)
1 (n/%)	282 (82.94)	226 (80.71)	0.77
2 (n/%)	49 (14.41)	46 (16.43)
>2 (n/%)	9 (2.65)	8 (2.86)

Pearson's chi-square test used to compare two groups; all other individual complications compared by using Fisher's exact test

Total category: two-sample t-test used to compare means of two groups.

PAPS = prior abdominal or pelvic surgery.

The surgical and post-operative course of patients is shown in Table 3, and the groups are compared by using univariate analysis. As noted, the eRARP group had shorter OR times (188.96 ± 54.17 minutes vs 197.92 ± 45.35 minutes, p = 0.003) and length of hospital stay (LOS; 1.13 ± 0.45 days vs 1.33 ± 1.08 days, p = 0.003). All original operative notes were reviewed for the mention of adhesiolysis that contributed to either increased operative difficulty or prolonged operative time. The tRARP group had a higher rate of this occurrence (14.3% vs 0.9%, p < 0.0001). For all three cases in the eRARP group, this was in reference to the adhesions that had formed between the posterior aspect of the prostate and the rectum, a phenomenon largely believed to be due to prior transrectal ultrasound-guided prostate needle biopsy. One of these three patients had also recently undergone a recent transurethral resection of the prostate.

Table 3.

Surgical and Post-Operative Course

	eRARP	tRARP	p-Value
OR time, minutes (mean ± SD)	188.96 ± 54.17	197.92 ± 45.35	0.003
Extensive lysis of adhesions (n/%)	3 (0.9)	40 (14.3)	<0.0001
EBL, mL (mean ± SD)	210.74 ± 141.95	190.79 ± 125.45	0.06
LOS, days (mean ± SD)	1.13 ± 0.45	1.33 ± 1.08	0.003
TCR (mean ± SD)	10.39 ± 2.47	10.65 ± 2.14	0.18
Follow-up, days (mean ± SD)	1016.94 ± 1103.28	543.91 ± 599.79	<0.0001
Prostate weight, g (mean ± SD)	58.05 ± 18.18	58.94 ± 22.24	0.59
Pathological Gleason sum (n/%)			<0.0001
5 and 6	159 (48.2)	56 (20.3)
7	157 (47.6)	189 (68.5)
8	12 (3.6)	16 (5.8)
9	2 (0.6)	15 (5.4)
Pathological T stage (n/%)			0.01
T0	2 (0.59)	1 (0.36)
T2a	66 (19.47)	43 (15.36)
T2b	9 (2.65)	5 (1.79)
T2c	177 (52.21)	122 (43.57)
T3a	67 (19.76)	86 (30.71)
T3b	18 (5.31)	22 (7.86)
T4	0 (0)	1 (0.36)
Nerve sparing (n/%)			<0.0001
None	120 (35.29)	145 (51.79)
Unilateral	105 (30.88)	98 (35)
Bilateral	115 (33.82)	37 (13.21)
Pelvic lymphadenectomy			<0.0001
Yes	165 (48.53)	257 (91.79)
No	175 (51.47)	23 (8.21)

Continuous measurements: OR time, EBL, LOS, catheter removal, follow-up, prostate weight (two-sample t-test).

Categorical Variables: Prostatectomy Gleason sum score and pathological T stage (Fisher's exact test); Nerve sparing and pelvic lymphadenectomy (Pearson's chi-square test).

Note: Pelvic lymphadenectomy was the standard template in all cases (eRARP and tRARP).

Frequency missing: path. T stage (1).

EBL = estimated blood loss; LOS = length of hospital stay; OR = operating room; TCR = time to catheter removal.

A higher number of eRARPs were performed early in the series and consequently, they had longer follow-up times (1016.94 ± 1103.28 days vs 543.91 ± 599.79 days, p < 0.0001). Patients in the eRARP group had lower pathological Gleason sum scores (p < 0.0001) and pathological T stage (p = 0.01). The eRARP group had higher rates of nerve-sparing procedures (p < 0.0001) and lower rates of pelvic lymphadenectomies (pelvic lymph node dissection [PLND]) (p < 0.0001). A trend was noted toward lower EBL in the eRARP group (190.79 ± 125.45 mL vs 210.74 ± 141.95 mL, p = 0.06). Groups were similar with regards to TCR and prostate weight. When analyzing only patients who had D'Amico intermediate- or high-risk disease, patients in the eRARP group were less likely to have received a PLND compared with those in the tRARP group: 120/134 (89.6%) vs 202/204 (99.0%), p < 0.0001.

A comparison of individual complications is shown in Table 4. As noted, each complication was categorized as intra-operative, early post-operative, or late post-operative. The eRARP group had a lower rate of ileus/small bowel obstruction/Ogilvie's (0% vs 3.21%, p = 0.0007). All other complications were similar between the groups. The eRARP group had a lower rate of overall complications (9.41% vs 15.0%, p = 0.03) and lower early post-operative complications (Table 5; 8.53% vs 12.86%, p = 0.08). No differences were noted in intra-operative complications, late post-operative complications, or Clavien–Dindo complications.

Table 4.

Complications—Individual Counts

Time period	Complication group	Extra (n = 340)	Trans (n = 280)	p-Value
Intraop	Obturator nerve injury	1 (0.29)	0 (0)	1.00
	Rectal injury	0 (0)	2 (0.71)	0.50
	Ureteral injury	0 (0)	1 (0.36)	1.00
Early post-op	Abscess/infected mesh	3 (0.88)	4 (1.43)	1.00
	Clostridium difficile infection	1 (0.29)	1 (0.36)	1.00
	Cardiac (minor)	1 (0.29)	4 (1.43)	0.37
	Clot retention/blocked foley	1 (0.29)	1 (0.36)	1.00
	DVT/PE	8 (2.35)	3 (1.07)	0.22
	Hematoma/hemorrhage	5 (1.47)	4 (1.43)	1.00
	Ileus/partial small bowel Obstruction/Ogilvie's	0 (0)	9 (3.21)	0.004
	Lymphocele	2 (0.59)	6 (2.14)	0.29
	Urine leak/anastomotic disruption	6 (1.76)	3 (1.07)	0.50
	UTI/epididymoorchitis	3 (0.88)	5 (1.78)	0.72
	Acute urinary retention	3 (0.88)	4 (1.43)	1.00
	Wound infection	2 (0.59)	0 (0)	0.50
Late post-op	Bladder neck contracture	4 (1.18)	0 (0)	0.12
	Chronic lymphedema	0 (0)	1 (0.36)	1.00
	Chronic pelvic pain	0 (0)	1 (0.36)	1.00
	Distal urethral stricture/meatal stenosis	1 (0.29)	2 (0.71)	1.00
	Formation inguinal hernia	1 (0.29)	1 (0.36)	1.00

Fisher's exact test used to compare individual complications between two groups.

DVT = deep vein thrombosis; PE = pulmonary embolism; UTI, urinary tract infection.

Table 5.

Complications—Binary (Yes vs No)

	eRARP	tRARP	p-Value
Overall (n/%)			0.03
Yes	32 (9.41)	42 (15)
No	308 (90.59)	238 (85)
Intra-op (n/%)			0.33
Yes	1 (0.29)	3 (1.07)
No	339 (99.71)	277 (98.93)
Early post-op (n/%)			0.08
Yes	29 (8.53)	36 (12.86)
No	311 (91.47)	244 (87.14)
Late post-op (n/%)			0.97
Yes	6 (1.76)	36 (12.86)
No	334 (98.24)	244 (87.14)
Clavien–Dindo classification (n/%)			0.85
I–II	22 (68.75)	29 (70.73)
III–IV	10 (31.25)	12 (29.27)

Categorical variables: overall, early post-op, late post-op, Clavien–Dindo classification (Pearson's chi-square); intra-op (Fisher's exact test).

A broader comparison was also performed between those patients in our series who underwent PAPS (eRARP and tRARP, n = 620) and those who did not (n = 1850). No differences were noted in binary (yes/no) intra-operative complications (4/620 [0.6%] vs 7/1850 [0.4%], p = 0.48), early post-operative complications (65/620 [28%] vs 167/1850 [24.8%], p = 0.32), late post-operative complications (11/620 [1.8%] vs 46/1820 [2.5%], p = 0.39), or overall complications (74/620 [11.9%] vs 208/1850 [11.2%], p = 0.69).

Regression analysis was used to control for covariates that may influence outcomes in this series (Table 6). Age, BMI, ASA, performance of PLND, D'Amico risk classification (high, intermediate, low), presence of nerve sparing (unilateral, bilateral, none), presence of positive margin, and number of prior abdominal or pelvic procedures (1, 2, >2) were included in the models. After adjusting for the effects of the covariates, the tRARP group had a significantly higher LOS (p = 0.0222). All other outcome measures tested were similar. Table 7 expands the analysis for the impact of the approach (tRARP vs eRARP) on LOS, showing the effects of each individual covariate. As seen, none were independently associated with LOS, although trends were noted for PLND (patients with PLND have lower LOS) and unilateral nerve sparing (patients with unilateral nerve sparing have higher LOS).

Table 6.

Regression Analysis with Model Selection to Study the Effect of Approach (Transperitoneal Robot-Assisted Radical Prostatectomy vs Extraperitoneal Robot-Assisted Radical Prostatectomy) on Various Peri- and Post-Operative Outcomes

	Poisson or linear regression		Logistic regression
Outcome	Estimate	Standard error	Odds ratio	95% Confidence interval		p-Value
LOS	0.19	0.08	—	—	—	0.02
OR time	−1.48	4.34	—	—	—	0.73
EBL	−18.96	11.97	—	—	—	0.11
TCR	0.30	0.22	—	—	—	0.18
Overall complications (# of complications per patient)	0.27	0.23	—	—	—	0.25
Early post-op complications (# of complications per patient)	0.31	0.25	—	—	—	0.22
Overall complications (binary)	—	—	1.51	0.86	2.65	0.15
Early post-op complications (binary)	—	—	1.42	0.78	2.57	0.25
Calvien–Dindo Complications (I–II vs III–IV)	—	—	0.82	0.22	3.14	0.78

Note: Covariates used in these models were age, BMI, ASA score, PLND, D'Amico risk category (high, intermediate, low), nerve sparing (unilateral, bilateral, none), presence of positive margin, and PAPS (1, 2, and >2 procedures).

PLND = pelvic lymph node dissection.

Table 7.

Poisson Regression Analysis for Length Of Hospital Stay

	Estimate	Standard error	p-Value
Approach
tRARP	0.19	0.08	0.02
eRARP	0	0	—
Individual covariate
Age	0.003	0.006	0.64
BMI	−0.005	0.008	0.57
ASA	0.02	0.08	0.79
PLND	−0.21	0.12	0.07
D'Amico risk classification
High	0.09	0.14	0.54
Intermediate	0.14	0.10	0.16
Low	0	0	—
Nerve sparing
Unilateral	−0.17	0.09	0.06
Bilateral	−0.11	0.11	0.34
None	0	0	—
Positive margin	0.17	0.11	0.14
PAPS
2	−0.05	0.10	0.66
>2	0.17	0.20	0.40
1	0	0	—

None of the covariates tested were independently associated with LOS, although trends were noted for PLND (negative association) and unilateral nerve sparing (positive association).

Discussion

During tRARP, PAPS may affect surgical outcomes due to the possible need to perform adhesiolysis, with associated access-related complications. PAPS may also affect outcomes of subsequent intra-abdominal operations, and this has been studied for many different organ systems, including, but not limited to, gastrointestinal, hepatic, renal, and gynecologic.^13

–16 Using data from a large national database, Kumakiri and colleagues¹⁶ reported that patients with a history of PAPS were at an increased risk for complications and longer hospital stay during subsequent laparoscopic surgery.¹⁷ Intra-abdominal adhesions may significantly alter surgical planes, often necessitating early adhesiolysis, risking injury to the bowel and other intrabdominal structures. During RARP, injuries may also occur away from the operative site, secondary to the blind passage of instruments through an assistant trocar. PAPS away from the site of RARP (or trocar sites) may not affect outcomes.

During a tRARP, the abdominal cavity is first entered, followed by secondary entry into the extraperitoneal space, on the bladder take-down step. Accessing the extraperitoneal space at the outset as in eRARP theoretically avoids potential adhesions and, thus, mitigates the associated risk of injuries. Surgeons experienced in retroperitoneoscopic renal procedures have cited these as a rationale for using the extraperitoneal approach in patients with PAPS.¹⁸ Several groups have reported on total extraperitoneal IHR after previous abdominal surgery and found no increase in peri- or post-operative complications, OR time, or hospital stay.^19,20

Similarly, eRARP may have significant advantages in this setting, justifying the need for surgeons to add both techniques to their armamentarium, and to most effectively individualize patient care.^21,22 Other publications have focused on the impact of PAPS on RARP, whereas our study is the first to specifically compare eRARP with tRARP in this setting. Ball and colleagues analyzed a series of minimally invasive prostatectomies (extra- and trans-peritoneal, lapraroscopic, and robotic) that had PAPS vs those that did not and found no differences in perioperative complications between the groups.²³ Using multivariate regression analysis, Yong et al. noted that PAPS was not associated with poorer outcomes in patients undergoing RARP, although the approach was not specified.²⁴

Stolzenburg and colleagues looked at a cohort of eRARPs and stratified them according to prior surgery type and location.²⁵ They found no difference in complications, OR time, or reintervention rate between the no prior surgery group and any of the previous surgery groups. Bernstein et al. looked at the outcomes of patients who underwent tRARP with a history of PAPS vs a cohort of patients without PAPS and found increased OR time but similar perioperative outcomes.²⁶ In a similar study, Siddiqui and colleagues found no differences in perioperative outcomes.²⁷

A limitation of this article is that this is a non-randomized, retrospective study. Our data set also comprises a highly select group of patients, as evident by the differences noted in patient and disease characteristics. On univariate analysis, eRARP was superior with respect to OR time, EBL, and LOS. This group had a lower incidence of gastrointestinal and overall complications, with a trend toward lower early post-operative complications. After controlling for covariates in our multivariate regression analysis, only LOS was lower in the eRARP group. One explanation for this may be the lower rate of gastrointestinal complications. The event rate was, however, too low to test with a multivariate regression model. Since the majority of eRARPs were performed earlier in the study, the differences noted might also be attributed to the surgeon's learning curve.

Although certain patient or disease factors may have influenced the decision to perform eRARP or tRARP, operative cases in this series performed from 2003 to 2007 were predominanty eRARP and from 2010 to 2015 were mainly tRARP. From 2008 to 2009 was a transition period where the two approaches were used relatively evenly. However, the decision of which approach to use was ultimately up to the discretion and capabilities of the surgeon, thus introducing selection bias.

It is a commonly held belief that PLND may be more difficult to perform extraperitoneally and also that lymphocele formation is more common after such a procedure.^28,29 Thus, patients felt to need a PLND were more likely to have a tRARP. Further, eRARP's were generally performed more frequently at the beginning of the series, an era when patients were more commonly likely to undergo RARP for low-risk disease (as opposed to being placed under an active surveillance protocol). Largely as a result of these two phenomena, the tRARP group comprises patients with higher risk disease. This has significant implications in terms of nerve sparing, margin status, and pathological grade/stage. The higher rate of PLNDs in the tRARP group also affects OR time and potentially EBL. These factors were taken into consideration in a multivariate regression model.

In this study, we chose to exclude patients with a history of prior IHRm. Although there have been no studies directly comparing tRARP with eRARP in the setting of IHRm, it is a commonly held belief that fibrosis and inflammation from previous mesh placement obliterate the extraperitoneal space and make subsequent creation of the extraperitoneal space much more difficult or even impossible without large peritoneotomies.^29
–31 Thus, many surgeons consider this a contraindication to eRARP. This effect may be more pronounced with prior laparoscopic bilateral extraperitoneal IHRm, but no studies have been published to confirm this. Although our initial hypothesis was that prior intra-abdominal or pelvic surgery would favor eRARP (for reasons previously listed), IHRm would theoretically have the opposite effect and favor tRARP. This cohort is unique and deserves independent study; thus, we felt that grouping it with other intra-abdominal operations would confound the data.

Conclusions

Patients with PAPS can safely undergo either eRARP or tRARP. Our group advocates the use of the former approach in this setting, because it circumvents scar tissue and adhesions in the peritoneal cavity that are created from prior operations. This prevents the need for adhesiolysis and its associated risks. After controlling for covariates in our multivariate regression model, we demonstrated a shorter LOS, which we feel is largely a result of the aforementioned phenomenon. Fewer gastrointestinal complications were noted in univariate analysis, but the event rate was too low to test further with multivariate regression analysis.

Footnotes

Acknowledgments

The authors are grateful to Ingrid Mikk and Bonita Powell.

Author Disclosure Statement

No competing financial interests exist.

Abbreviations Used

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