Impact on Anesthetic Agent Consumption After Autonomic Neural Blockade as Part of a Combined Anesthesia Protocol: A Randomized Clinical Trial

Abstract

BACKGROUND:

The intraoperative autonomic neural blockade (ANB) was found safe and effective in controlling pain and associated symptoms and reducing analgesic consumption after laparoscopic sleeve gastrectomy (LSG). This study evaluated whether ANB performed at the outset of LSG reduces anesthetic consumption and promotes hemodynamic stability.

METHODS:

This prospective, double-blinded, randomized trial involved patients undergoing LSG in 2 high-volume institutions. Patients were randomized to receive ANB either at the onset or the end of the procedure. The primary outcome measure was the consumption of remifentanil and sevoflurane. Secondary outcomes included Aldrete scale score differences in the recovery room and hemodynamic stability during the surgery.

RESULTS:

In total, 80 patients (40 in the ANB at the onset group and 40 in the control group) were included for analysis. The consumption of remifentanil was significantly lower in the onset group compared to the control group (mean difference -0.04 mcg/kg/min, 95% confidence interval [CI], -0.06 to -0.02; P < .0001). There were no differences in the Aldrete scale scores between the 2 groups. Mean heart rate (HR) and mean arterial pressure (MAP) were also significantly less during surgery in the ANB at the onset group. No complications related to the ANB occurred.

CONCLUSIONS:

Performing ANB at the onset of LSG is a safe and effective approach that reduces remifentanil consumption and promotes hemodynamic stability during the procedure. This technique holds promise for optimizing anesthesia management in LSG and other minimally invasive surgeries.

KEY POINTS.

• Question: Does using autonomic neural blockade (ANB) at the onset compared to the end of laparoscopic sleeve gastrectomy (LSG) impact anesthesia consumption, hemodynamic stability, and early recovery?

• Findings: The study found that patients receiving ANB at the onset of LSG had lower consumption of remifentanil and sevoflurane, improved hemodynamic stability, and equal postoperative recovery evaluated by the Aldrete scale while maintaining low levels of visceral pain, PONV, and analgesic consumption.

• Meaning: Using ANB at the onset during LSG can be a valuable adjunct to combined anesthesia providing significant benefits to patients.

Balanced general anesthesia, even if combined with local anesthesia or abdominal-wall field blocks such as a transversus abdominis plane (TAP), subcostal, or rectus sheath blocks, is insufficient to block the autonomic impulses released during most intra-abdominal visceral surgeries, especially during laparoscopic sleeve gastrectomy (LSG). These impulses are, in part, responsible for the hemodynamic changes observed during different phases of LSG and the subsequent visceral pain and associated symptoms, such as nausea and vomiting, observed in a substantial number of patients in the immediate postoperative period after LSG and other minimally invasive procedures.^1–5 Pain substantially impacts patients’ quality of life, recovery time, nursing time allocation, and resultant risk of opioid use, dependence, and abuse. Nausea, food intolerance, and pain are responsible for most readmissions after LSG and other bariatric procedures.^6,7 Many of these patients have associated respiratory impairments and other comorbidities. A recent randomized clinical trial (RCT) demonstrated that a novel approach, namely paragastric autonomic neural blockade (ANB), is safe and effective in addressing visceral pain while reducing the need for analgesics, including opioids, and the incidence of nausea and vomiting in the first 24 hours after an LSG.⁸

Similar beneficial effects were observed when implementing a variation of the autonomic blockade as an early step in cholecystectomy and other upper GI surgeries. In an unpublished observational series, we found that by performing ANB as the first step in LSG, the need for remifentanil and sevoflurane diminished, and hemodynamic stability increased while maintaining the previously reported reduction of postoperative visceral pain and associated symptoms.⁸ This RCT aims to confirm the effects observed when the ANB is performed at the onset of the LSG.

OBJECTIVES

1. To evaluate the impact of early ANB on the consumption of remifentanil and sevoflurane in the intraoperative period during LSG.

2. To evaluate the impact of early ANB on changes in hemodynamic parameters at different stages of the LSG.

3. To evaluate the recovery from anesthesia using the Aldrete scale 15 minutes and 1 hour after entering the postanesthesia care unit (PACU), comparing ANB performed at the onset versus at the end of the LSG.

METHODS

Study Design

The study protocol was registered before patient enrollment in ClinicalTrials.gov under the identifier NCT05668845 by the lead investigator J. Daes on November 26, 2022. This study is a prospective, double-blinded RCT involving patients undergoing LSG at 2 high-volume bariatric surgery institutions. The patients were randomized to parallel groups: LSG with ANB performed as the first step after trocar placement, and LSG with ANB performed immediately after suture reinforcement of the sleeve and before the leak test. Because of the proven benefit demonstrated in a previous RCT,⁸ we included ANB at the end of sleeve reinforcement as a control group instead of a placebo.

The study protocol adhered to the Helsinki Declaration and was approved by the Institutional Review Boards of Clínica Portoazul, Clínica Iberoamerica, and the ethics committee of U Simon Bolivar (No. 00405), and written consent was obtained from all patients. The reporting of this study complies with the CONSORT 2010 guidelines for reporting RCTs. A flow diagram of the progress through the phases of the parallel randomized trial of the 2 groups is found in Figure 1.

Figure 1.

Flow diagram of the progress through the phases of the parallel randomized trial of two groups: enrollment, intervention allocation, follow-up, and data analysis.

Patients

All adult patients scheduled for LSG at each participating institution between February 1 and May 1, 2023 were eligible for screening and consent for study inclusion. The exclusion criteria were inability to perform an ANB because of anatomical difficulties, need for revisional surgery, need for simultaneous hiatal hernia repair or other surgical procedures, conversion to open surgical procedures, allergies to local anesthetics or medications described in the anesthesia protocol, and intraoperative complications (eg, visceral, or vascular perforations, or anesthesia-related complications requiring admission to intensive care).

Sample Size

Sample size was determined using previous observational data comparing remifentanil consumption in an exploratory study before patient enrollment. The minimum clinically significant difference was defined as a dose reduction of at least 10% (corresponding to 100 mcg decrease in the total dose of remifentanil). To determine sample size, a 2-sample t-test comparing the mean total dose of remifentanil using parameters from the exploratory study (eg, standard deviation of 275 and 325 mcg). Using these parameters, the estimated sample size necessary to detect a reduction of 200 mcg in the total dose of remifentanil with a P-vale of .05 and a power of 80% was 37 patients in each group. We enrolled 40 patients in each group to allow for exclusions and other factors.

Randomization and Blinding

Randomization was performed using sealed envelopes stratified by the institution in blocks of 6. The data manager prepared these envelopes, stored the randomization list containing the final treatment assignments, and had access to the randomization list throughout the study. These sealed envelopes were placed in the patient’s chart and were not opened until the patient was in the operating room and general anesthesia was induced. The patient and the independent investigator assessing and recording the patient’s data were blinded to treatment arm assignments.

Data Collection

An independent investigator was responsible for collecting and recording the study data and was not present during the 2 periods when the blockade occurred (before the division of the greater omentum and after the leak test). The anesthesiologist recorded the data in these short periods. Patients’ age, sex, body mass index, current medications, and medical and surgical history were recorded prospectively at their visit to the preoperative clinic at the time of study enrollment with informed consent. The duration of the procedure was recorded in all patients. The primary outcomes were the amount of remifentanil (total µg and µg/kg/min) and sevoflurane (mL and mL/min) used during the LSG. The secondary outcomes were the Aldrete scale assessments at 15 minutes and 1 hour after surgery in all patients. These primary and secondary outcomes were determined a priori and included in the study registration at Clinicaltrials.gov. Post hoc secondary outcomes were also included in the study detailing mean arterial pressure (MAP) and heart rate (HR) at the different periods (utilizing the mean measurements at the initial division of the omentum, initial staple firing, and final staple firing on the stomach compared to the measurement on patient arrival to the operating room). All outcomes were assessed and analyzed on an intention-to-treat basis.

Statistical Analysis

To account for multiple comparisons in the primary outcomes, a Bonferroni correction was used for the 2 primary outcomes (remifentanil consumption in µg/kg/min and sevoflurane consumption in mL/min), and statistical significance was set as P-value <.025. The primary outcomes were analyzed with 2-sample t-tests to compare mean remifentanil and sevoflurane consumption between the 2 treatment arms. The normality assumption for the 2-sample t-tests was assessed using histograms and quantile-quantile (Q-Q) plots for each outcome. The secondary outcome was analyzed using the Mann-Whitney U test to compare the ordinal values of the Aldrete scale between the groups. In the post hoc analysis of secondary outcomes, the changes in intraoperative hemodynamic measurements were compared using 2-sample t-tests and normality was assessed as described for the primary outcome. Finally, the primary study outcomes were compared between the 2 study anesthesiologists using 2-sample t-tests.

Anesthesia Protocol

The 2 anesthesiologists in our group used the same standard anesthetic protocol as follows:

1. Premedication with pregabalin.

2. Induction with remifentanil 0.15 µg/kg/min ideal weight, propofol 1 to 2 mg/kg actual weight, and rocuronium initial bolus of 0.6 mg/kg ideal weight followed by 0.06 mg/kg maintenance 40 minutes after that.

3. Maintenance with sevoflurane at 1.5% to 2.5% with a minimum alveolar concentration (MAC) between 0.4 and 0.8, fresh gas flow at 1 L/min, and remifentanil between 0.08 and 0.3 µg/kg/min (ideal weight) in continuous intravenous infusion.

4. Before extubation, the analgesic protocol for all patients consisted of acetaminophen (1 g). Ondansetron, dexamethasone, and alizapride were routinely used during the induction of anesthesia as antiemetics.

5. Ventilatory parameters were at a maximum of 1.2 L/min, FiO₂ between 40% and 60%, positive end-expiratory pressure between 8 and 12 cmH₂O, and respiratory rate between 13 and 15 breaths per minute, keeping CO₂ between 35 and 45 mm Hg. Reversal of muscle paralysis was achieved as follows: if T1/T4 was >3, this was performed by adding atropine and neostigmine. Sugammadex (2–4 mg/kg) was used if T1/T4 was <3 associated with neostigmine.

All patients had basic standard and advanced anesthesia monitoring, including the bispectral index (BIS). The amount of remifentanil administered was calculated based on the consumed mix and the administered amount of sevoflurane determined by the anesthetic machine (Dräger Primus).

Assessment of the Hemodynamic Parameters

MAP and HR were measured at different stages of the procedure: on arrival to the operating room; after induction of anesthesia; at the start of the division of the greater omentum (baseline value), and at the end of the division; after the first staple division of the stomach and during the last staple division; at the start of the suture reinforcement of the staple line, 5 minutes after, and at the final knot of the reinforcement; during the leak test and 10 minutes after; and at the end of the procedure after the removal of the divided stomach.

Strategy to Modify Doses of Anesthetics

Remifentanil administration was reduced at 0.04 µg intervals until reaching a minimum administration of 0.1 µg/kg/min if HR or mean blood pressure diminishes 15% or more from the basal rate (with BIS between 40 and 60). If this measure proved insufficient, sevoflurane can be reduced until reaching an MAC of 0.6 if the BIS score is <60. Further need for hemodynamic stabilization was addressed using etilefrine 1 mg bolus or atropine 0.01 to 0.02 mg/kg (ideal weight). An increase in the hemodynamic parameters by >15% was addressed by increasing the remifentanil infusion up to 0.3 µg/kg/min. If hypertension or tachycardia persisted, it was handled by elevating sevoflurane up to 0.8% MAC if BIS remains between 45 and 60. Finally, patients with hemodynamic stability but with BIS <40 or >60 were managed by decreasing or increasing sevoflurane. The independent investigator ensured that the changes in the administration of remifentanil and sevoflurane complied with these parameters.

Surgical Procedures

LSG

The LSG technique performed by our group has previously been described elsewhere.^9,10 Three surgeons from our group (J.D., E.L., and A.H.) with extensive experience in LSG performed all procedures.

ANB

The autonomic neural block was performed with a 25-gauge needle attached to a venous catheter extension introduced through the left 12-mm port. The needle is capped during its introduction, and the cap is removed inside the abdomen using a grasper and kept under direct vision. Infiltration of 20 mL of non-diluted 0.5% bupivacaine plus dexamethasone (8 mg) was performed at 6 levels with careful aspiration preceding fluid infiltration. After elevating the stomach anteriorly with a grasper at the most proximal aspect of the lesser curvature and creating 2 windows at each side of the verticalized left gastric artery as depicted in Figure 2, infiltrations were performed at each side of the base of the left gastric artery (Supplemental Digital Content 1, Supplemental Figures 1 and 2, http://links.lww.com/AA/E603). Four more areas are infiltrated along the track of the anterior vagus nerve: at the esophago-gastric union, <2 cm, at the division of the vagus nerve, and the distal branches. When ANB is performed at the final stage of the procedure, the same maneuvers to expose the celiac ganglions are performed at the onset, but the infiltration is reserved for the end of the LSG. When blockade is performed at the end of the procedure, and the initial exposure of the celiac area proves difficult, elevating the sleeve medially and infiltrating the celiac area from the neo-greater curvature of the sleeve can facilitate the procedure. The procedure is rapid, reproducible, and proven safe in a previous RCT.⁸ However, it has a learning curve evident by the variation of the results between surgeons involved in our index publication and the fact that is currently done faster (<6 minutes) and more efficiently by all the surgeons involved. Details of the procedure are available.¹¹

Figure 2.

Elevating the stomach anteriorly with a grasper at the most proximal aspect of the lesser curvature and creating two windows at each side of the verticalized LGA by dividing the flimsy peritoneum in the area allows one to visualize the posterior aspect of the fundus on the left and the right crura on the right. The origin of the LGA corresponds to the target of the celiac ganglions. LGA indicates left gastric artery.

Laparoscopic Transversus Abdominis Block

After testing the sleeve with methylene blue, the laparoscopic TAP block was performed in all patients. We infiltrated 40 mL of 50% saline solution and diluted 0.5% bupivacaine into the posterolateral subcostal area on both sides. We confirm infiltration into the proper plane by observing fluid dissemination between the transversus abdominis and internal oblique muscle layers. We no longer use ultrasound guidance during TAP blocks.

RESULTS

A total of 81 patients were initially recruited for study inclusion. However, 1 patient was excluded before randomization as an appropriate anesthetic machine was unavailable to measure sevoflurane consumption. Forty patients were randomized to receive ANB at the onset of the procedure, while 40 received ANB at the end. One patient from the study group (ANB at the onset) did not receive the planned intervention after randomization due to a breach in the anesthesia protocol, as depicted in Figure 1. This patient was included in the intention-to-treat analysis as outlined in the methods.

Eighty patients were evaluated in the final analysis: 40 in the ANB at the onset group and 40 in the ANB at the end of the procedure group.

The 2 groups were comparable in age, sex, body mass index, comorbidities, history of abdominal surgery, and chronic analgesic use, as shown in Table 1.

Table 1.

Baseline Characteristics

Variable	Onset blockade (n = 40)	Terminal blockade (n = 40)	Standardized difference
Age, y, mean (SD)	35.3 (8.8)	35.2 (10.5)	0.01
Sex			0.85
Male	13 (32.5 %)	21 (52.5 %)
Female	27 (67.5%)	19 (47.50 %)
Body mass index, kg/m2, mean (SD)	36.7 (4.3)	38.3 (4.9)	0.36
Comorbidities
Hypertension	4 (10%)	7 (17.5%)	0.64
Diabetes mellitus	2 (5.0 %)	2 (5.0%)	0.00

Abbreviation: SD, standard deviation.

The control group had higher remifentanil consumption than the study group. When ANB was undertaken at the onset, the patient’s remifentanil consumption was 0.16 mcg/kg/min in comparison to 0.20 mcg/kg/min in the control group (mean difference 0.04 mcg/kg/min, 95% confidence interval [CI], 0.06 to 0.02; P < .0001 [Bonferroni adjusted significance level <0.025]). The sevoflurane consumption was higher in the control group, but it did not reach statistical significance (mean difference +0.17 mL/min, 95% CI, 0.003 to 0.; P = .088). The duration of the procedure was not significantly different between the 2 groups studied (Table 2).

Table 2.

Duration of the Procedure and Anesthetics Consumption

Variable	0nset (n = 40)	Terminal (n = 40)	P-value
Anesthesia duration, min, mean (SD)	86.6 (16.9)	81.48 (14.2)	.1488
Gas total consumption, mL, mean (SD)	12.4 (3.0)	13.1 (3.4)	.3051
Gas consumption, mL/min, mean (SD)	0.15 (0.04)	0.16 (0.05)	.0880
Remifentanil total consumption, mcg, mean (SD)	899.2 (344.3)	1082.1 (339.9)	.0200
Remifentanil consumption, mcg/kg/min, mean (SD)	0.16 (0.04)	0.20 (0.05)	<.0001

Abbreviation: SD, standard deviation.

There was no difference in the Aldrete score measured 15 and 60 minutes after LSG between the studied groups (Table 3).

Table 3.

Immediate Postoperative Recovery Outcomes measured at 15 and 60 Min After Surgery Using the Aldrete Scale

Variable	Onset blockade (n = 40)	Terminal blockade (n = 40)	P-value
Aldrete score, mean (SD)
15 min	9.1 (1.0)	8.9 (0.8)	.3153
60 min	9.8 (0.4)	9.8 (0.6)	.5645

Abbreviation: SD, standard deviation.

Similar to our previous RCT,⁸ the mean MAP and HR decreased 10 minutes after the blockade regardless if performed at the onset or at the end. (Supplemental Digital Content 2, Supplemental Table 1, http://links.lww.com/AA/E604).

When the mean baseline HR and MAP were compared to the average of 3 moments during surgery (at the start of the greater omentum division and the first and last stomach stapling) proportional decreases in MAP (8.2 vs 0.6 mm Hg, P = .0349) and mean HR (3.3 vs increasing 4.8 beats/min, P = .0056) were greater in the onset group (Table 4).

Table 4.

Comparison Between Baseline MAP and HR and the Average of Three Moments During Surgery, With Blockade Performed at the Onset Versus at the End of Laparoscopic Sleeve Gastrectomy

At the onset (n = 40)							At the end (n = 40)						Comparing moments
MAP baseline	Moments		Mean			Difference	MAP baseline		Moments		Mean	Difference	P-value
89.35 (11.7)	Division omentum		81.2				87.1 (12.8)		Division omentum		83.6
	First staple		80.7						First staple		84.4
	Last staple		81.05						Last staple		90.6
	Average of the periods		81.25 (12.5)			8.1 (14.0)			Average of the periods		86.6 (12.7)	0.5 (16.5)	.0290
At the onset (n = 40)								At the end (n = 40)					Comparing moments
HR baseline		Moments		Mean	Difference			HR baseline		Moments	Mean	Difference	P-value
80.78 (13.9)		Division omentum		78.3				78.07		Division omentum	80.65
		First staple		78.2						First staple	82.7
		Last staple		77.1						Last staple	84.8
		Average of the periods		77.9 (11.6)	2.85 (13.0)					Average of the periods	82.8 (12.7)	4.7 (10.9)	.0062

Abbreviations: HR, heart rate; MAP, mean arterial pressure.

No patients developed complications related to the ANB beyond mild, self-limited bleeding in 2 patients at one of the infiltration sites. All bleeding resolved intraoperatively without further intervention. The patients tolerated well the hemodynamic changes observed after the block; in 4 patients, the anesthesiologist administered phenylephrine (0.5–1 mg) (2 patients) or atropine (0.5 mg) (2 patients) to regulate the HR and MAP.

DISCUSSION

Visceral pain and associated symptoms, especially nausea and vomiting, are frequent after many laparoscopic procedures, particularly LSG. Many strategies have been described to manage postoperative bariatric and other minimally invasive procedures’ symptoms, including intravenous analgesics, magnesium sulfate, opioids, wound infiltration of long-acting local anesthetics, TAP blocks, antiemetics, corticosteroids, and epidural anesthesia.^3,12–16 We implemented an enhanced recovery protocol based on some of these strategies before describing the ANB, with partial success. Although De Silva et al¹⁷ reported that a hypogastric nerve block reduced opioid consumption during benign gynecological procedures, no reports had described intraoperative autonomic blockade acting on parasympathetic and sympathetic pathways to reduce anesthetic and opioid consumption and preventing visceral pain and associated symptoms during upper gastrointestinal and other general surgical procedures. Our previous randomized control trial demonstrated the safety and efficacy of paragastric autonomic blockade after LSG as a multimodal pain and associated symptom management therapy.⁸ The main objective of the present RCT was to study the effects of performing ANB at the onset of LSG and compare them to when ANB is performed at the end (as was done in our prior RCT). We observed a significant reduction in remifentanil consumption when ANB was performed at the onset of LSG. We did not observe a difference among the studied groups in the early recovery of the patients measured by the Aldrete score at 15 and 60 minutes after LSG. There was a tendency toward hemodynamic stability (lower MAP and HR) in this group of patients despite receiving less remifentanil and sevoflurane. This effect may prevent the peaks of hypertension and tachycardia commonly observed in these obese, multimorbid, high-risk patients at given times during bariatric procedures. There was a reduction in the HR and MAP of approximately 10 beats/min and 10 mm Hg, respectively, 10 minutes after ANB (at any time), a possible effect of sympathetic inhibition. We believe this observation can be used as an intraoperative marker of an effective blockade. We are evaluating the effect of ANB timing on postoperative pain scores, presence of nausea and vomiting, and the number of administered doses of analgesics––especially opioids––up to 24 hours after LSG. Using the ANB as a part of combined anesthesia may contribute to cost containment, global warming reduction,¹⁸ prevention of opioid overuse, intraoperative hemodynamic instability, and better communication between the surgeon and the anesthesiologist.

The primary outcome outlined in the protocol in Clin.Trial.Gov under the identifier NCT05668845 included both remifentanil total consumption in mcg and mcg/k/min. At the time of sample size calculations, remifentanil total dose (in mcg) was used. As the study was further developed, it was felt that mcg/kg/min better reflected the anesthetic dose received by the patients while accounting for differences in procedural time. This adjustment in study design does reflect a shortcoming of our study.

The reproducibility of the results of this study is a potential limitation, given the introduction of a novel ANB technique. Surgeons who perform these laparoscopic blocks should be skilled minimally invasive surgeons. We demonstrated the existence of an ANB learning curve with inter-surgeons’ variation in the results in our first publication on ANB and also by observing an improvement on time and efficiency to perform the blockade. The ANB blockade for upper GI surgeries, as described in the section on technique with accompanying figures and video link, has been better standardized. The equipment is inexpensive and readily available. Using a Williams needle or retractable needles like the Carr-Locke through a catheter percutaneously may make this procedure more attractive to some surgeons.

Another limitation to reproducing the published results may be the difficulty of standardizing the anesthesiologists’ strategy to modify the administration of anesthetics according to the hemodynamic and BIS parameters. We noticed a variation between the anesthesiologists’ reported consumption of remifentanil and sevoflurane in this study, with 1 reporting a higher consumption of remifentanil and the other of sevoflurane probably reflecting personal preferences (Supplemental Digital Content 2, Supplemental Table 2, http://links.lww.com/AA/E604).

Another limitation could be the lack of a placebo group. Our group considered it unethical not to use a proven maneuver to improve patients’ quality of life. Moreover, comparing the ANB at the onset with the blockade at the end allowed us study differences in recovery and the effect of pre-emptied anesthesia on pain and other parameters (not reported in this study).

As with any surgical procedure, ANB carries a risk of complications. These can include infection, bleeding, and adverse reactions to the anesthetic agents used. In this series––as well as in our first series––only minor complications have been observed, mainly easily to control minor bleedings at the side of injection. Careful application of the local anesthetic, with attention to avoiding intravascular injection by meticulous aspiration, is crucial during ANB.

In general, the hemodynamic changes observed after the blockade were well tolerated. Performing the procedure in the surgical theater allows for close monitoring of the patient’s vital signs and ensures immediate access to any necessary medical interventions. This controlled environment provides a higher level of safety during the procedure compared to percutaneous celiac blockades, which are typically performed in the radiology suite.

Strategies to prolong ANB effects using liposomal bupivacaine (Exparel; Pacira Pharmaceuticals) proved successful in a small series of patients, although these results have not yet been published. We are evaluating the effect of ANB for colonic resections, cholecystectomies, and other minimally invasive procedures, as well as measuring the effect of the autonomic blockade on inflammatory mediators such as cortisol, noradrenaline, and interleukin-6.

CONCLUSIONS

The intraoperative autonomic blockade performed at the onset of LSG demonstrated its safety and effectiveness in this series of cases. ANB use at the onset of LSG resulted in a significant reduction in opioid consumption. It seemed to promote intraoperative hemodynamic stability during critical phases of the procedure. Previous reports have shown its potential to decrease postoperative pain, nausea, vomiting, and the need for analgesics. Further prospective studies are warranted to validate these findings and explore the benefit of ANB in other minimally invasive procedures.

DISCLOSURES

Name: Jorge Daes, MD, FACS.

Contribution: This author helped conceive and design the article, analyzed the data, and wrote the article.

Conflicts of Interest: None.

Name: Rafael Pantoja, MD.

Contribution: This author helped design the study––especially the anesthesia protocol––and contributed data.

Conflicts of Interest: None.

Name: Jorge Luquetta, MD.

Contribution: This author helped design the study––especially the anesthesia protocol––and contributed data.

Conflicts of Interest: J. Daes has received honoraria from Medtronic and BD concerning hernia surgery.

Name: Elika Luque, MD.

Contribution: This author helped design the study and contributed data.

Conflicts of Interest: None.

Name: Andrés Hanssen, MD, FACS.

Contribution: This author helped design the study and contributed data.

Conflicts of Interest: A. Hanssen has received honoraria from Medtronic and Johnson & Johnson concerning hernia surgery.

Name: Jose Rocha, FACS.

Contribution: This author helped collect, organize, and archive data.

Conflicts of Interest: None.

Name: David J. Morrell, MD.

Contribution: This author helped design the study, performed the statistical analysis, and critically reviewed the article.

Conflicts of Interest: None.

This manuscript was handled by: Tong J. Gan, MD.