Impact of Combination of Local Anesthetic Wounds Infiltration and Ultrasound Transversus Abdominal Plane Block in Patients Undergoing Robot-Assisted Radical Prostatectomy: Perioperative Results of a Double-Blind Randomized Controlled Trial

Abstract

Objective:

To determinate benefits of the combination of local anesthetic wounds infiltration and ultrasound transversus abdominal plane (US-TAP) block with ropivacaine on postoperative pain, early recovery, and hospital stay in patients undergoing robot-assisted radical prostatectomy (RARP).

Methods:

The study is double-blinded randomized controlled trial. Our hypothesis was that the combination of wound infiltration and US-TAP block with ropivacaine would decrease immediate postoperative pain and opioids use. Primary outcomes included postoperative pain and opioids demand during the hospital stay. Secondary outcomes were nausea/vomiting rate, stool passing time, use of prokinetics, length of hospital stay (LOS), and 30-days readmission to the hospital for pain or other US-TAP block-related complications.

Results:

A total of 100 patients who underwent RARP were eligible for the analysis; 57 received the US-TAP block with 20 mL of 0.35% ropivacaine (US-TAP block group) and 43 did not receive US-TAP block (no-US-TAP group). All the patients received the local wound anesthetic infiltration with 20 mL of 0.35% ropivacaine. US-TAP block group showed a decreased mean Numerical Rating Scale (NRS) within 12 hours after surgery (1.6 vs 2.6; p = 0.02) and mean NRS (1.8 vs 2.7; p = 0.04) with lesser number of patients who used opioid (3.5% vs 18.6%; p = 0.01) during the first 24 hours. Moreover, we found a shorter mean LOS (4.27 vs 4.72, days; p = 0.04) with a lower requirement of prokinetics administration during the hospital stay (21% vs 72%; p < 0.001). No US-TAP block-related complications were reported.

Conclusion:

Combination of anesthetic wound infiltration and US-TAP block with ropivacaine as part of a multimodal analgesic regimen can be safely offered to patients undergoing RARP and extended pelvic lymph node dissection. It improves the immediate postoperative pain control, reducing opioids administration and is associated to a decreased use of prokinetics and shorter hospital stay.

Introduction

Enhanced recovery after surgery programs demonstrated that the implementation of a standardized, multidisciplinary clinical care pathways for patients undergoing radical prostatectomy (RP) improved efficiency reducing postoperative surgical stress and recovery times without increasing complication rates or hospital readmissions.^1,2

Robot-assisted surgery revolutionized the urological surgical approach and centers that treat diseases such as prostate cancer (PCa) with robotics are rapidly increasing.³ Robot-assisted radical prostatectomy (RARP) has become standard of care for PCa over the last decade in many countries around the world.⁴ Advantages of robotic approach are reduced estimated blood loss (EBL) and transfusion requirements, postoperative complications, early hospital discharge, and improved postoperative pain control.^3,5,6 With smaller incisions, the postoperative discomfort along with postoperative pain drugs and narcotics demand are significantly reduced compared with open surgery.⁷

The ultrasound-guided transversus abdominis plane (US-TAP) block has been described for analgesia after laparoscopic and open abdominal procedures.⁸ The term TAP block usually refers to a nerves blockade, targeting dermatomes from T6 to L1. This block relies on injection of local anesthetic in the neurovascular plane between the transversus abdominis and internal oblique muscles.⁵

In the present double-blind randomized controlled trial (RCT), we performed US-TAP blocks as part of a multimodal approach to postoperative pain control. The aim of this study is to determine benefits of the combination of local anesthetic wounds infiltration and US-TAP block with ropivacaine on postoperative pain, early recovery, and hospital stay in patients undergoing RARP.

Methods

The study had Institutional Review Board approval but did not undergo local Ethical Committee approval since performing TAP-block after abdominal and pelvic procedures is an option that has been already described in several specialities becoming routine practice in many institutions all over the world.^9,10 Each patient provided informed signed consent.

Patients were allocated in the two groups, using a computer-generated randomization sequence using http://randomization.com.¹¹ To reduce the selection biases, this study was designed as a double-blinded RCT: neither surgeons nor anesthesiologists during the procedure, neither patients nor the staff nurse after the procedure, knew if the patients were allocated in the US-TAP block or no-US-TAP block arms.

From August 2016 to April 2017, 100 consecutive patients with diagnosis of PCa undergoing RARP at Department of Urology, Azienda Ospedaliera Universitaria Integrata of Verona, Italy were enrolled and randomized in two groups: US-TAP block group and no-US-TAP block groups. Patients who received US-TAP block and local anesthetic wounds infiltration with 0.35% of ropivacaine were considered the tests population (TP), while patients who received only local wounds infiltration with 0.35% ropivacaine were considered the control population.

All the procedures were performed by two expert surgeons (W.A. and V.D.M.) who have overcome their learning curve. Two expert anesthesiologists (N.M. and E.P.) performed the same general anesthesia protocol in all the patients and the US-TAP block in patients allocated in the TP-arm.

Preoperative data included demographics such as age (years), body mass index (BMI), American Society of Anesthesiologists Status Classification (ASA) and prostate specific antigene (PSA) (ng/mL), Gleason Grading Group at the time of the diagnosis, bowel function (regular or styptic), and previous abdominal surgeries.

Intraoperative characteristics such as procedure type, inclusion of lymph node dissection, type of nerve sparing, length of anesthesia, surgery, and console time, EBL, immediate postoperative opioid use, and time in the post-anesthesia care unit (PACU) were collected. All specimens were retrieved trough a mid-abdominal 5-cm incision at the level of camera port.

After the procedure we administered to all patients acetaminophen 1000 mg every 8 hours for the 24 hours after the surgical procedure and subsequently on demand. A “rescue drug dose” with opioid drugs (Tramadol 100 mg) was administered whenever the aforementioned analgesic protocol was insufficient. Pain intensity was evaluated by our staff nurse using the Numerical Rating Scale (NRS)¹² three times every day (7 a.m.–3 p.m.–11 p.m.) during the hospital stay.

In absence of flatus and stool passing or abdominal tension without signs and symptom of abdominal occlusion, metoclopramide 10 mg/2 mL intravenus infusion up to a maximum of three doses in 24 hours was administered.

Criteria for discharge were absence of abdominal/pelvic pain, lack of medical and surgical complications, no significant hematuria by bladder catheter, normal kidney function, and oral feeding tolerance with efficient bowel functional recovery (flatus and stool passing).

US-TAP block

General anesthetic protocol was performed as previously described.¹³ US-TAP block was performed by the anesthesiologists according to the randomization protocol. A high-frequency linear US transducer (Siemens^® Sonoline G60S) was placed in transverse plane at the midaxillary line between the lower costal margin and the iliac crest. TAP was identified, and a 22 g touchy needle was introduced using an in-plane approach. When the tip of the needle was in the TAP, 2 mL of saline was injected to verify the correct position. Then, 20 mL of 0.35% ropivacaine was injected. All TAP blocks were performed bilaterally accordingly to previously validated protocol.¹⁴ A maximum of 3 mg/kg of 0.35% ropivacaine was allowed. The potential benefit in using TAP block with of Ropivacaine has been previously described.¹⁴ To reduce potential different analgesic effects related to the use of different drugs¹⁵ we decided to use the same local anesthetic for both wound infiltration and TAP block.

Outcomes

Primary outcomes included postoperative pain and opioids demand during the hospital stay. Secondary outcomes were nausea/vomiting rate, stool passing time, use of prokinetics, length of hospital stay (LOS), and 30-days readmission to the hospital for pain or other US-TAP block-related complications.¹⁶ In abdominal and pelvic surgery, conditions such as inflammatory response and prolonged postoperative pain could induce secretion of endogenous opioids, which have been contributing to postoperative ileus.^17,18 In animal model it has been demonstrated that endogenous opioids production can be detected up to 10 days after abdominal laparotomy.¹⁹ Moreover, it has been reported that postoperative stress may persist further 5 days after RARP.²⁰ For these reasons, we evaluated the entire postoperative course to assess pain control and bowel function.

Statistical analysis

Our hypothesis was that the combination of wound infiltration and US-TAP block with ropivacaine would decrease immediate postoperative pain and opioids use. Assuming a 40% difference in opioid consumption during the first 24 hours between groups^10,21 and power of 80% with a level of significance of 0.05 it was estimated that 31 patients would be required in each arm. We enrolled a total of 100 patients who were prospectively and randomly allocated.

Data on continuous variables are reported as means with their respective standard deviation (SD) and differences between the two groups analyzed by the t-Student test or Mann–Whitney U test as appropriate (e.g., pain score outcomes). Data of categorical variables are shown as percentages, and differences between groups analyzed with Pearson's chi-squared test or Fisher exact test as appropriate. All statistical analyses were performed using IBM SPSS Statistics 24.0. All tests were two-sided with p < 0.05 considered to indicate statistical significance.

Results

Figure 1 depicts the CONSORT flowchart.²² A total of 100 patients who underwent RARP ± extended pelvic lymph node dissection (ePLND) were eligible for the analysis; 57 received the US-TAP block with 20 mL of 0.35% ropivacaine (US-TAP group) and 43 did not receive US-TAP block (no-US-TAP group). All the patients (100) received the local wound anesthetic infiltration with 20 mL of 0.35% ropivacaine.

FIG. 1.

CONSORT flowchart

Table 1 shows patients baseline and perioperative characteristics. Mean (SD) age was 64.6 (6.9) years, BMI was 25.5 (3.0) kg/m² with a mean ASA score of 1.9 (0.4). Randomization groups were comparable in terms of age, BMI, ASA score, bowel function, preoperative PSA, and Gleason Grading Groups. As regards to operative outcomes, 39 patients underwent RARP and 61 RARP plus ePLND. Mean blood loss was 314.4 (269) mL. Patients neither required intraoperative transfusions nor open conversion. Mean anesthesiological, operative, and console times were 269 (71.5) minutes, 226.7 (64) minutes, and 191 (69.5) minutes respectively. Mean PACU time was 23.6 (18.4) minutes. Randomization groups were comparable regarding all the aforementioned intraoperative outcomes except for mean EBLs, which have been found significantly higher in no-US-TAP block group (436.5 vs 225 mL; p: 0.001). In the postoperative course, the US-TAP block group showed a shorter mean length of stay (4.2 vs 4.7; p = 0.04) with a reduced number of patients who required prokinetics administration during the hospital stay (12% vs 31%; p < 0.001). There were no complications related to the US-TAP block procedures. No signs or symptoms of local anesthetic toxicity were recorded.

Table 1.

Baseline and Perioperative Characteristics

	Entire cohort	US-TAP block		p-Value
	Entire cohort	No	Yes	p-Value
Patient, n (%)	100 (100)	43 (43)	57 (57)
Age, year, mean (SD)	64.6 (6.9)	64.5 (6.2)	64.7 (7.5)	0.86
BMI, kg/m², mean (SD)	25.5 (3.0)	26 (2.8)	25 (3.1)	0.16
Bowel function
Regular, n (%)	97 (97)	42 (98)	55 (96)	1
Stiptic, n (%)	3 (3)	1 (2.3)	2 (3.5)
ASA, mean (SD)	1.9 (0,4)	2 (0.4)	2 (0.4)	0.94
ASA I, n (%)	8 (8)
ASA II, n (%)	84 (84)
ASA III, n (%)	6 (6)
PSA, mean (SD)	7.0 (3,3)	6.9 (2.9)	7.1 (3.5)	0.67
Gleason groups
GGG 1, n (%)	41 (41)	18 (41.9)	23 (40.4)	0.73
GGG 2, n (%)	38 (38)	13 (30.3)	25 (43.9)
GGG 3, n (%)	16 (16)	10 (23.2)	6 (10.5)
GGG 4, n (%)	4 (4)	2 (4.6)	2 (3.5)
GGG 5, n (%)	0 (0)	0 (0)	0 (0)
GGG 6, n (%)	1 (1)	0 (0)	1 (1.7)
Previous abdominal surgery, n (%)	5 (5)	1 (2.3)	4 (7)	0.39
Procedure type
RARP, n (%)	39 (39)	15 (34.9)	24 (42.1)	0.53
RARP + ePLND, n (%)	61 (61)	28 (65.1)	33 (57.9)
Nervesparing
Extrafascial, n (%)	27 (27)	11 (25.6)	16 (28)	0.59
Interfascial, n (%)	30 (30)	11 (25.6)	19 (33.3)
Intrafascial, n (%)	41 (41)	19 (44.2)	22 (38.6)
N/R, n (%)	2 (2)	2 (4.6)	0 (0)
Estimated blood loss, mean (SD)	314.4 (269)	436.5 (341.9)	225 (151)	0.001
Anesthesiology time, minutes, mean (SD)	269 (71.5)	281 (80.9)	260.3 (63.6)	0.19
Console time, minutes, mean (SD)	226.7 (64)	234.7 (70.7)	220.9 (58.9)	0.32
Operative time, minutes, mean (SD)	191.9 (69.5)	203.5 (84.8)	185.6 (59.5)	0.31
PACU time, minutes, mean (SD)	23.6 (18.4)	22.6 (6.4)	24.1 (21.7)	0.67
Immediate postoperative opioids Administration, n (%)	31 (31)	16 (37.2)	15 (26.3)	0.38
Time to remove the drain, days, mean (SD)	0.6 (0.5)	0.6 (0.5)	0.5 (0.5)	0.52
LOS, days, mean (SD)	4,4 (1)	4.7 (1.4)	4.2 (0.6)	0.04^*
US-TAP block-related complication, n (%)	3 (0)	—	3 (5.2)	0.17
Days to stool passing, mean (SD)	2.3 (0.8)	2.3 (0.9)	2.3 (0.7)	0.5
Prokinetics administration, n (%)	43 (28)	31 (72)	12 (21)	0.001^*

Statistically significant p < 0.05.

ASA = American Society of Anesthesiologists; BMI = body mass index; EBL = estimated blood loss; GGG = gleason grading group; LOS = length of hospital stay; N/R = not reported; PACU = post-anesthesia care unit; RARP = robot-assisted radical prostatectomy; SD = standard deviation; US-TAP = ultrasound transversus abdominal plane.

Table 2 depicts daily care assessment by US-TAP block use. US-TAP block group showed a decreased mean 24 hours NRS (1.8 vs 2.7; p = 0.04), with a lesser mean NRS scale at 11 p.m. measurement (1.6 vs 2.6: p = 0.02) and lesser use of opioid at the day of procedure (3.5% vs 18.6%; p = 0.01). When postoperative pain and painkiller doses administered at I, II, and III postoperative day were compared, a nonstatistically significant trend was found in favor of US-TAP block group. No differences have been found regarding bowel stool passing time, nausea, and vomit rate during the hospital stay.

Table 2.

Daily Postoperative Care Assessment

	Entire cohort	US-TAP block		p-Value
	Entire cohort	No	Yes	p-Value
Day of the surgical procedure
First NRS in ward, mean (SD)	2.35 (2.9)	2.7 (3.1)	2.2 (2.6)	0.63
3 p.m. NRS, mean (SD)	2.8 (2.6)	3.3 (2.5)	2.4 (2.7)	0.1
11 p.m. NRS, mean (SD)	2.0 (2.0)	2.6 (2.3)	1.6 (1.7)	0.02^*
24 Hours NRS, mean (SD)	2.2 (1.9)	2.7 (2.0)	1.8 (1.8)	0.04^*
Nausea, n (%)	21 (21)	7 (16.2)	14 (24.5)	0.32
Vomiting, n (%)	3 (3)	0 (0)	3 (5.3)	0.25
Stool passing, n (%)	2 (2)	2 (4.6)	0 (0)	0.19
No. of painkiller dose, mean (SD)	1.4 (0.9)	1,3 (1)	1.5 (0.8)	0.14
Use of opioids rescue dose, n (%)	10 (10)	8 (18.6)	2 (3.5)	0.01^*
I Post-operative day
7 a.m. NRS, mean (SD)	2.1 (2.4)	2.3 (2.5)	2 (2.4)	0.61
3 p.m. NRS, mean (SD)	1.45 (1.9)	1.8 (2)	1.1 (1.8)	0.08
11 p.m. NRS, mean (SD)	1.7 (2.5)	1.6 (2.6)	1.7 (2.4)	0.81
24 Hours NRS, mean (SD)	1.7 (1.6)	1.9 (1.9)	1.6 (1.4)	0.36
Nausea, n (%)	9 (9)	4 (9.3)	5 (8.8)	1
Vomiting, n (%)	4 (4)	2 (4.6)	2 (3.5)	1
Stool passing, n (%)	15 (15)	9 (20.9)	6 (10.5)	0.25
No. of painkiller dose, mean (SD)	1.3 (1.1)	1.3 (1.1)	1.2 (1.1)	0.88
Use of opioids rescue dose, n (%)	3 (3)	2 (4.6)	1 (1.7)	0.42
II Postoperative day
7 a.m. NRS, mean (SD)	1.2 (2.0)	1.6 (2.4)	0.8 (1.5)	0.07
3 p.m. NRS, mean (SD)	0.9 (1.7)	1.4 (2)	0.6 (1)	0.05
11 p.m. NRS, mean (SD)	0.7 (1.7)	0.8 (1.9)	0.6 (1.6)	0.56
24 Hours NRS, mean (SD)	0.9 (12)	1.3 (1.5)	0.7 (1)	0.06
Nausea, n (%)	2 (2)	1 (2.3)	1 (1.7)	1
Vomiting, n (%)	0 (0)	0 (0)	0 (0)	—
Stool passing, n (%)	49 (49)	19	30	0.41
No. of painkiller dose, mean (SD)	0.7 (0.9)	0.8 (1)	0.6 (0.8)	0.45
Use of opioids rescue dose, n (%)	0 (0)	0 (0)	0 (0)	—
III Postoperative day
7 a.m. NRS, mean (SD)	0.2 (0.6)	0.2 (0.6)	0.2 (0.5)	0.8
3 p.m. NRS, mean (SD)	0.2 (0.8)	0.2 (0.5)	0.1 (0.7)	0.13
11 p.m. NRS, mean (SD)	0.2 (0.7)	0.3 (0.8)	0.1 (0.4)	0.34
24 Hours NRS, mean (SD)	0.2 (0.5)	0.1 (0.4)	0.2 (0.5)	0.67
Nausea, n (%)	2 (0)	1 (2.3)	1 (1.7)	1
Vomiting, n (%)	1 (1)	1 (2.3)	0 (0)	0.44
Stool passing, n (%)	83 (83)	36 (83.7)	47 (82.4)	1
No. of painkiller dose, mean (SD)	0.3 (0.6)	0.4 (0.7)	0.2 (0.5)	0.22
Use of opioids rescue dose, n (%)	0 (0)	0	0	—

NRS = Numerical Rating Scale.

Discussion

US-TAP block was first described by Rafi as a new technique with the aim to reduce the immediate postoperative pain in open surgery.²³ Since then, several trials evaluated the efficacy of the US-TAP block. Recent meta-analyses showed the benefits US-TAP blocks in many surgical procedures.^10,24 Nevertheless, trials in the urological field are sparse and show inconsistent results.

Elkassabany et al.²⁵ conducted a prospective, randomized double-blinded study evaluating the effects of US-TAP block (20 mL of 0.5% bupivacaine) vs placebo on pain control within 24 h after open retropubic RP. They showed that the US-TAP block group had lower pain scores and required less opioid administration in the immediate time after the surgery.²⁵ Contrarily, in another RCT, Skjelsager and colleagues found that neither US-TAP block nor wound infiltration with ropivacaine (40 mL of 0.75% ropivacaine) improved a basic multimodal analgesic regimen after open RP.²⁶

Robotic surgery showed a reduced postoperative pain when compared with open approach enabling a shorter hospital stay and increasing patient satisfaction.²⁷ Abdominal pain is lesser after a robotic procedure and in most of cases well controlled with a small amount of analgesics administered during the first 24–48 hours after surgery.²⁸

Poor literature exists about the use of US-TAP block in robotic surgery. Hutchins and colleagues, showed that the US-TAP block (10 mL of 1.3% liposomal bupivacaine) was useful to provide better postoperative pain control and was associated with lower postoperative maximal pain scores and LOS in patients undergoing robot-assisted hysterectomy.²⁹

Faasse et al.³⁰ compared perioperative outcomes in children with adjunctive caudal blocks, US-TAP blocks (0.3 mL/kg of 0.125%–0.25% bupivacaine), or no regional anesthesia for common robot-assisted surgical procedures in pediatric urology. The author stated that administration of caudal blocks should be considered for children of suitable age undergoing robot- assisted surgery involving either the upper or lower urinary tract.³⁰

In regard to robotic RP, few reports have been published. Sternlicht and associates evaluated the efficacy and safety of two volumes (20 mL vs 40 mL) of liposome bupivacaine administered via US-TAP infiltration in patients undergoing robotic laparoscopic prostatectomy finding no differences between two groups.³¹ Recently, in a RCT, Dal Moro and associates⁹ compared US-TAP block (200 mL of 0.25% levobupivacaine) injected in four sites with a placebo control group. The authors showed the benefit of US-TAP block in terms of pain control with a decreased use of opioids demand in the first 24 hours after the surgery. No data on gastrointestinal issues or hospital stay were reported.⁹

To the best of our knowledge this is the first RCT that compares the combination of wounds infiltration (20 mL of 0.35% Ropivacaine) and US-TAP block (20 mL of 0.35% Ropivacaine) with wounds infiltration only. We preferred to use ropivacaine because it is less lipophilic than bupivacaine and is less likely to penetrate large myelinated motor fibers, resulting in a relatively reduced motor blockade.¹⁵ The lower lipophilicity is also related with reduced potential for central nervous system toxicity and cardiotoxicity.³² We found a statistically significant decrease of postsurgical pain in the US-TAP block group compared with those in the control group with a decreased demand of tramadol rescue dose in the first 24 hours after the surgery. Patients in US-TAP block group reported an early bowel function recovery with lesser use of prokinetics drug compared with the control group without using enema or prokinetics drugs. The lesser prokinetics administration could be due to the lesser administration of tramadol, which could lead to opioid-induced constipation as consequence of the action of opioids on their receptors in the gastrointestinal tract.³³ Moreover, we found shorter LOS was demonstrated in patients who underwent US-TAP block as reported by other studies.²⁹ No differences were found between RARP and RARP plus ePLND. These findings suggest that the combination on wounds infiltration and US-TAP block with 0.35% of ropivacaine as part of a multimodal analgesic regimen in patients undergoing RARP is safe, effective, and may be warranted. Further investigation aimed to find predictors of US-TAP block failure are needed to delineate a more adequate patient “tailored fit” postoperative analgesia protocols.

Our findings highlight the impact of the combination of wounds infiltration (20 mL of 0.35% ropivacaine) and US-TAP block (20 mL of 0.35% ropivacaine) after RARP in the early discharge programs. Of note, in our public health care program is challenging to discharge patients in 1–2 post operative day (POD) after major surgery as it happens in some American, European, and Australian organizations. This is mainly due to different cultural behaviors and does not necessarily translate into a bad or good clinical practice.^34s In this context, our study provides important evidence to improve clinical practice as part of enhancer recovery programs after surgery.

Conclusion

Combination of anesthetic wound infiltration and US-TAP block with ropivacaine can be safely offered to patients undergoing RARP and ePLND. It may improve the immediate postoperative pain control, reducing opioids administration and is associated to a decreased use of prokinetics and shorter hospital stay.

Ethical Approval

All procedures performed in the present study involving human participants were in accordance with the ethical standards of the Institutional Research Committee and with the 1964 Helsinki declaration and its last amendments or comparable ethical standards.

Informed Consent

Informed consent was obtained from all individual participants included in this study.

Footnotes

Author Disclosure Statement

No competing financial interests exist.

Abbreviations Used

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