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Transversus Abdominis Plane Block Versus Caudal Epidural for Lower Abdominal Surgery in Children: A Double-Blinded Randomized Controlled Trial

Bryskin, Robert B. MD*; Londergan, Bevan MD*; Wheatley, Rebekah MD*; Heng, Renee MD*; Lewis, Marjorie MD*; Barraza, Mark MD*; Mercer, Erica MD*; Ye, Gang PhD

doi: 10.1213/ANE.0000000000000779
Pediatric Anesthesiology: Research Report

BACKGROUND: Transversus abdominis plane block (TAPB) has emerged as a safe and effective regional anesthesia technique for providing postoperative lower abdominal analgesia. Complications associated with TAPB are rare and pose a lower overall risk to the patient receiving a TAPB versus a caudal block, which is considered the gold standard for pediatric lower abdominal regional anesthesia. Our study hypothesis was that TAPB would initially be equivalent to caudal block in providing postoperative pain control but would also show improved pain relief beyond the anticipated caudal duration.

METHODS: This study was a double-blinded randomized controlled trial. Forty-five children between the ages of 1 and 9 undergoing bilateral ureteral reimplantation surgery through a low transverse incision were enrolled. Narcotic requirement, pain scores (FLACC/Wong-Baker FACES), episodes of emesis, and antispasmodic requirement were recorded in the postanesthesia care unit (PACU) and at 6-hour intervals for 24 hours from the time of block placement. Our protocol used a multimodal approach toward pain management in all children, including randomized regional technique, scheduled ketorolac, morphine as needed, and the antispasmodic, oxybutynin, as needed.

RESULTS: Morphine requirement showed no statistical difference during the initial 12 hours (all P ≥ 0.68 at PACU, 6 and 12 hours). However, at 24 hours those patients randomized to receive the TAPB required less cumulative morphine than the caudal group (0.05 mg/kg ± 0.06 vs 0.09 mg/kg ± 0.07, P = 0.03). There was a trend toward fewer episodes of emesis in the TAPB group which reached statistical significance at 18 and 24 hours (6 vs 1 episodes, P = 0.03; and 9 vs 2 episodes, P = 0.02). Pain scores (0–10) were higher in the TAPB group in the PACU (3.46 ± 2.69 vs 1.71 ± 2.1, P = 0.02), but there were no significant differences at all subsequent time points (all P ≥ 0.10). The TAPB group also had a higher requirement for the bladder antispasmodic oxybutynin at 24 hours (0.49 ± 0.58 vs 0.28 ± 0.17, P = 0.003).

CONCLUSIONS: TAPB provided superior analgesia compared with the caudal block at 6 to 24 hours after block placement, as demonstrated by a statistically significant decrease in cumulative opioid requirement, which was the primary end point. The lower incidence of emesis in the TAPB group likely reflected the decreased opioid consumption. Although TAPB appears to be less effective than the caudal block in preventing viscerally mediated bladder spasms, as evidenced by the higher PACU pain scores and increased oxybutynin requirement at 24 hours, this effect may be counteracted in future clinical practice by scheduled administration of the antispasmodic medications. Considering the overall safety advantages of the TAPB over the caudal block, this should be considered a preferred regional technique for lower abdominal surgeries.

Published ahead of print April 21, 2015

From the *Department of Anesthesiology, Nemours Children’s Clinic, Jacksonville, Florida; and Nemours Clinical Management Program, Orlando, Florida.

Accepted for publication February 19, 2015.

Published ahead of print April 21, 2015

Funding: Nemours Research Programs.

The authors declare no conflicts of interest.

Reprints will not be available from the authors.

Address correspondence to Robert B. Bryskin, MD, Department of Anesthesiology, Nemours Children’s Clinic, 807 Children’s Way, Jacksonville, FL 32207. Address e-mail to Rbryskin@nemours.org.

Ureteroneocystostomy (ureteral reimplantation) is a prototypical lower abdominal pediatric surgery performed via a low transverse incision to correct vesicoureteral reflux in children. The incidence of vesicoureteral reflux with related urinary tract infection is approximately 2.2% of females and 0.6% of males,1 and surgical management via ureteral reimplantation remains the cornerstone of treatment to prevent recurrent infection and scarring of the urinary system.2 Postoperatively, patients experience somatosensory pain from the incision site and visceral irritation and discomfort arising from bladder spasms. The typical duration of hospital stay is 24 to 72 hours and is commonly defined by the time required to achieve adequate pain control. Historically, pain management included indwelling epidural catheters, but more recent management has favored shorter duration of hospital stay and single-dose caudal block.3,4

Caudal epidural anesthesia is considered the gold standard regional technique for pain management after pediatric pelvic and lower abdominal procedures because it blocks both somatic and visceral pain. The caudal block has a low complication rate (0.7 per 1000),5 provides 4 to 6 hours of analgesia, and results in improved patient pain scores than in patients having general anesthesia alone.6–9 Nevertheless, as a neuraxial block, the potential complications are more serious than those associated with peripheral nerve blocks,6,10 and it is contraindicated in cases of impaired hemostasis, bacteremia, and neuraxial abnormality. Ultrasound is increasingly used to perform caudal block as an adjunct tool to guide cannula placement and to demonstrate accurate deposition of local anesthetic in the caudal epidural space; however, its utility for decreasing the rate of complications has yet to be determined.11,12

An increased understanding of abdominal wall anatomy has led to the introduction of the transversus abdominis plane block (TAPB) for managing pain after lower abdominal surgery.13–15 In the adult population, TAPB provides reliable unilateral sensory block in the T10-L1 distribution with a single injection,16–19 and resulted in a significant decrease in postoperative pain scores and opioid requirements after major abdominal surgeries.13,16,20,21 Similar outcomes have been observed in pediatric studies,22–25 and analgesia after TAPB in pediatric patients is thought to last 15 to 24 hours.23 Complications associated with TAPB are rare, especially when performed under direct ultrasound visualization, lack long-term consequences, and do not require additional interventions.24,26

With the emergence of new regional techniques which have been found to be safe and effective comes the need to compare the efficacy of the new technique to the gold standard, particularly when the new technique has a lower risk profile. To date, there have been no studies comparing postoperative pain control in children undergoing lower abdominal surgery receiving the caudal block versus those receiving the TAPB. We hypothesized that pain control, as reflected by opiate requirement and pain intensity scores, in children undergoing intravesicular ureteral reimplantation, would be similar between the caudal and TAPB groups for the anticipated duration of caudal anesthesia (4–6 hours) but would be lower in the TAPB group for the remainder of the 24-hour period.

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METHODS

Study Participants and Setting

Approval was obtained from the Nemours Clinical Research Committee on March 31, 2011, and Institutional Review Board at the Baptist Medical Center Downtown (IRB# 10–51) before enrolling patients in this study. Patients aged 1 to 9 years scheduled for intravesicular ureteral reimplantation surgery were identified by the urologists at Nemours Children’s Clinic. A member of the research team discussed the study with the family of each patient. Children were excluded if (1) their coagulation status or anatomic variations precluded safe placement of either TAPB or caudal epidural, (2) there was a preexisting chronic pain disorder, (3) there was a history of constipation that persisted despite appropriate treatment and that may have affected postoperative pain assessments, (4) additional procedures were planned via a separate incision at the time of the ureteral reimplantation, or (5) there was a contraindication to receiving the medications described in the protocol. Participation was offered to those who met eligibility criteria, and written consent was obtained from the child’s parent or legal guardian. Assent for study participation was also obtained from older children. All surgical procedures were performed at Wolfson’s Children’s Hospital (Jacksonville, FL). The study was registered with ClinicalTrials.gov on June 9, 2014 (NCT02160821, Principal Investigator: Robert B. Bryskin, MD).

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Randomization and Blinding

We performed a prospective double-blinded randomized control trial. Patients were separated into 2 blocks based on age (block 1, ages 1–4; block 2, ages 5–9) to minimize pain reporting heterogeneity. This was deemed necessary since younger children may have difficulty differentiating incisional and bladder spasm pain. Within each block, patients were randomized to receive either a TAPB or a caudal based on a random allocation table generated before enrollment. Postoperative pain management was performed by the surgical team according to a set protocol. Surgeons left the operating room during block performance and were blinded to the type of block performed. Small Band Aids were placed at each of the 3 potential needle puncture sites immediately after block completion to prevent block allocation deciphering based on the injection location. The nursing staff responsible for postoperative pain assessment was educated at the initiation of the study and re-educated half way through enrollment to the postoperative expectations in this patient population, consistent use of pain scoring and differentiation between bladder spasm discomfort and somatic pain. They were blinded to the patient’s assigned block. The study personnel who performed data collection and the biostatistician analyzing the data remained blinded to the allocation of each patient. The details of the block performed were placed in a sealed envelope, to be opened only at the conclusion of the study or if medically necessary.

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Intervention

Patients received midazolam 0.5 mg/kg by mouth if indicated preoperatively. General anesthesia was induced with inhaled induction (nitrous oxide, oxygen, and sevoflurane). Fentanyl 2 μg/kg IV was administered before incision, and general anesthesia was maintained with either sevoflurane or desflurane and air oxygen mixture. Blocks were performed before surgical incision.

To ensure that our results were not confounded by inconsistent or failed blocks, all blocks (including caudal) were performed by one of the 5 investigators using ultrasound guidance and uniform techniques with predefined end points for needle placement and local anesthetic spread. Continuous, in-plane ultrasound guidance using M-turbo ultrasound machine with the L25e 6–13 MHz linear transducer (Sonosite Inc., Bothell, WA) was used to guide needle placement and to confirm local anesthetic spread. If appropriate spread of local anesthetic could not be confirmed, the patient was excluded from the study.

Patients in the treatment group underwent a bilateral ultrasound-guided lateral TAPB with 0.5 mL/kg of 0.25% bupivacaine + epinephrine 1:200,000 (Hospira, Inc., Lake Forest, IL) injected at each side. TAPB was performed with a 27-gauge 1.25'' needle or a 22-gauge 2'' blunt-tip needle, depending on the length of the needle required to complete the block. Needle placement was considered successful when the needle tip was located between the lateral aponeurosis site of transversus abdominis muscle and internal oblique muscle. This position was chosen because it most closely results in needle-tip placement and local anesthetic spread within the lumbar triangle of Petit described in posterior TAPB approach.27 The control group received 1 mL/kg of 0.25% bupivacaine + epinephrine 1:200,000 via a single caudal injection through a 22-gauge 1'' angiocath. Ultrasound guidance was used to assist with cannula placement into the caudal space and to verify ventral displacement of the dura/dilation of the caudal epidural space with injection of local anesthetic.

A foley catheter was placed intraoperatively and maintenance fluids were administered at 1.5 times maintenance. Ketorolac 0.5 mg/kg was administered upon surgical closure.

Pain was assessed postoperatively using either FLACC (Face, Legs, Activity, Cry, Consolability) Scale or Wong-Baker FACES scale as deemed appropriate by the evaluating nurse. The established nursing practice in our hospital dictates application of FLACC scale in children who have difficulty verbalizing pain and in sleeping children (regardless of age). The Wong-Baker FACES scale is utilized for patients capable of self-assessment. Orders for postoperative analgesia were standardized as follows: (1) morphine 0.05 mg/kg IV every 2 hours as needed for moderate to severe pain (FLACC/FACES ≥ 3), (2) ketorolac 0.5 mg/kg IV every 6 hours scheduled for 24 hours provided urine output was >0.5 mL/kg/h, and (3) oxybutynin 0.2 mg/kg by mouth every 8 hours as needed for bladder spasms.

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Outcome Measures

Data were collected via chart review after patient discharge. Data collected included morphine dosing by weight (mg/kg), pain scores (FLACC/FACES, 0–10 Likert scale), antispasmodic requirement (mg/kg), episodes of emesis, sedation scores, oxygen desaturation (<92%), supplemental oxygen use (yes/no), use of opiate reversing medications (yes/no), incidence of complications, and time from end of surgery to diet toleration. These data were recorded in the PACU and at 6-hour intervals through 24 hours from the time of the block placement.

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Statistical Analysis

Before data collection, we conducted a power analysis and sample size determination for our study based on the outcomes (pain scores and opiate requirements) reported in a previously published study.23 To detect a reduction of 50% in cumulative morphine requirement and pain score at 24 hours postoperatively, a minimum of 22 study subjects per group (44 total) was needed to achieve the power of 0.80 (2-sided test with α = 0.05).

Patient baseline and demographic data distribution by control and treatment groups were analyzed using χ2 test (if cell counts were <5, Fisher exact test was used) (Table 1). The main analytical objective of this study was to assess the difference in outcomes between the caudal and TAPB groups. First of all, our data showed that sedation scores, oxygen desaturation, supplemental oxygen use, and complications had almost no change over measurement points; thus, they were excluded from our modeling analysis. Our statistical analysis focused on 4 outcomes: cumulative morphine use, pain scores, cumulative antispasmodic requirement, and episodes of emesis. For each study subject, data were repeatedly measured over time; therefore, the measurements of a subject at different time points were expected to have certain correlation (within-subject correlation).

Table 1

Table 1

To account for the correlation in our analysis, we chose to use the generalized linear mixed model (GLMM) method. In the GLMM analysis, the first-order autoregressive [AR(1)] variance–covariance structure was chosen to model the repeated patterns. We used this covariance structure because we expected that the neighboring measurements would have stronger correlation than those at distant time points (e.g., the pain score at 6 hours would be more correlated with pain score at 12 hours than at 24 hours). The GLMM analysis assessed overall significance across time between the caudal and TAPB groups. At the same time, the multiple comparisons within the GLMM framework were conducted to assess statistical difference between caudal and TAPB at each time point (Table 2). Assumptions for GLMM include normality of random effects and residuals as well as independence among random effects and errors. It should be noted that although normality assumption of response data is not required for GLMM analysis, data distribution needs to be a member of the exponential family, such as lognormal, binary, or γ distribution. For some of our data (emesis and pain score), the assumptions for the GLMM analysis were not fully satisfied. After appropriate transformation, the emesis data and pain score data still showed cert’ain abnormality with relatively large skewness. Therefore, the interpretation of the results associated with the emesis data and pain score data should be made with certain caution.

Table 2

Table 2

Multiple statistical software were used in our analyses. The SPSS V22 was used to perform the descriptive analysis and the χ2 tests. Statistical Analysis System (SAS) V9.2 (SAS Institute Inc., Cary, NC) was used to conduct the GLMM analyses via PROC MIXED and GLIMMIX procedures. The estimates of differences of means between groups, including their confidence intervals (Table 2), are presented in their original data scales, which were generated via corresponding inverse link function in PROC GLIMMIX procedure.

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RESULTS

From October 2011 through November 2013, 47 patients were enrolled in this study. Twenty-four patients in the TAPB group and twenty-one patients in the caudal group completed the study protocol and were analyzed for the primary outcome. Two patients were excluded (one from each group) due to deviations from the protocol. In one of the 2 patients, acetaminophen was erroneously administered for pain on 2 occasions by a nurse caring for the patient. In the second patient, localized swelling was noted immediately after administration of the first dose of IV morphine. Morphine was discontinued, and the patient received hydromorphone for subsequent pain management. Patient’s demographic information and baseline data distribution are shown in Table 1. Due to the nature of the procedure being performed, there were more female than male patients overall; however, male to female ratio was similar in each group (P = 0.98). ASA physical status did not differ significantly between groups. Most patients received a premedication before induction. All but 1 patient underwent bilateral ureteral reimplantation.

Our main findings are presented in Table 2. Morphine requirement showed no statistical difference between the groups during the initial 12 hours (all P ≥ 0.68 at PACU, 6 and 12 hours). However, at 24 hours those patients randomized to receive the TAPB required less cumulative morphine than the caudal group (0.05 mg/kg ± 0.06 vs 0.09 mg/kg ± 0.07, P = 0.03). Comparison of the interval morphine consumption demonstrates a clear temporal pattern (Fig. 1) of decreasing morphine use for the treatment group but not for the control group.

Figure 1

Figure 1

Pain scores (0–10) were higher in the TAPB group in the PACU (3.46 ± 2.69 vs 1.71 ± 2.1, P = 0.02), but by 6 hours that difference had resolved (1.81 ± 2.46 vs 1.54 ± 0.24, P = 0.70), and there was no significant difference between the groups at subsequent time points (all P > 0.10; Table 2 and Fig. 2).

Figure 2

Figure 2

The TAPB group had a higher requirement for the bladder antispasmodic oxybutynin throughout the study with statistical significance reached at 24 hours (0.49 ± 0.58 vs 0.28 ± 0.17, P = 0.003; Table 2).

There was a trend toward fewer episodes of emesis in the TAPB group which reached statistical significance at 18 and 24 hours (6 vs 1 episodes [0.29 ± 0.56 vs 0.04 ± 0.20], P = 0.03; and 9 vs 2 episodes [0.43 ± 0.75 vs 0.09 ± 0.29], P = 0.02; Table 2 and Fig. 3).

Figure 3

Figure 3

No patient experienced excessive sedation or clinically significant desaturations in the 24 hours after block placement, and there were no statistically significant difference in these variables among the 2 groups at any of the 6-hour intervals (P > 0.9 at each interval in both variables). All blocks were completed in 15 minutes or less (average 9.2 ± 3.5 minutes for the caudal and 10.4 ± 3.5 minutes for the TAPB, P = 0.29), and there were no block related complications.

Subgroup analysis of the outcomes stratified by the age block (32 patients in block 1 [ages 1–4] and 13 patients in block 2 [ages 5–9]) echoed the overall study outcome trends in opioid consumption, pain scores, antispasmodic use, and incidence of emesis. Statistical comparison by age block was limited due to the smaller sample size of block 2. This was not unexpected considering the traditionally younger age of surgical intervention for vesicoureteral reflux. The only statistically significant difference between the 2 groups was noted in the PACU morphine consumption. The older patients in block 2 receiving more morphine than block 1 patients (0.05 mg/kg vs 0.02 mg/kg, P = 0.03). This deviation had resolved by 6 hours.

A subgroup analysis was also performed to examine whether the choice of volatile anesthetic (sevoflurane versus desflurane), used for maintenance of anesthesia, influenced early postoperative outcomes. This variable was not controlled in our study design, and per discretion of the attending anesthesiologist 11 patients received sevoflurane and 34 received desflurane. No statistically significant outcome differences were demonstrated among the 2 groups either in PACU or at a 6-hour interval.

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DISCUSSION

TAPB has emerged as a safe and effective block for lower abdominal analgesia in children; however, the evidence required to establish optimal indications for the block in children is lacking, and no previous studies have directly compared the efficacy of TAPB with either caudal blocks or epidural analgesia in children.22–24,26 Our study prospectively compared TAPB with caudal for pain management after ureteral reimplantation surgery, a procedure for which both blocks are well suited.

Our results showed that TAPB provided superior analgesia compared with the caudal block at 6 to 24 hours after block placement, as demonstrated by a statistically significant decrease in cumulative opioid requirement, which was the primary end point. The relative longevity of the TAPB was evident in the greater interval opioid requirement in the caudal group after the initial 6-hour mark (Fig. 1). Patients randomized to the caudal group demonstrated consistent interval morphine consumption during the 6-hour intervals leading up to 12 hours, 18 hours, and 24 hours, while morphine consumption dropped to near zero for the patients in the TAPB group.

Pain scores in the PACU period were significantly higher in the TAPB group but were equivalent at all subsequent time points. The caudal block’s coverage of visceral stimulation arising from bladder spasms and foley catheter discomfort likely accounted for this difference. Bladder spasms are an important component of postoperative pain in children undergoing intravesicular ureteral reimplantation, and this pain has been observed to persist in a high percentage of patients despite epidural blockade.28 Scheduled use of ketorolac has been shown to reduce the incidence/severity of bladder spasms and, together with oxybutynin (as needed), was incorporated into our multimodal postoperative pain management approach in an attempt to minimize the impact of superior visceral coverage by the caudal. The increased use of oxybutynin in the TAPB group at all time intervals further supports this observation, but the impact of visceral discomfort was not sufficient to result in a greater need for morphine in the PACU or to cause pain scores to be elevated in the TAPB group beyond the PACU period. We plan to counteract this anticipated visceral discomfort in future clinical practice by administering the first dose of oxybutynin preoperatively and on a scheduled basis thereafter. Only 7 patients across both groups did not require oxybutynin (4 caudal and 3 TAPB), interestingly less than the number of patients who required no morphine; thus, scheduled dosing of this medicine would expose very few additional children to oxybutynin. No oxybutynin-related side effects were observed among patients in our study.

Local anesthetic with epinephrine was the only drug used for both types of blocks in this trial. This was designed to allow direct comparison between the caudal block and the TAPB for overall efficacy and side-effect profile without confounding the comparison with adjunct medicines. Nevertheless, the use of caudal adjuncts is common in clinical practice and warrants discussion. Epinephrine may prolong the duration of caudal analgesia, but it has minimal systemic side effects and was used in this study primarily to detect unintentional intravascular injection in both groups.29,30 Several non-opioid additives, including ketamine, neostigmine, and midazolam, have been shown to significantly prolong caudal analgesia; however, concerns of neurotoxicity, increased incidence of postoperative nausea and vomiting, and lack of availability of preservative-free preparations in the U.S. have excluded these from our clinical practice.30–33 Opioids have also been shown to prolong caudal analgesia but are accompanied by an unattractive side-effect profile, including nausea, pruritis and, less commonly but potentially serious, respiratory depression.3,34,35

Clonidine is a non-opioid adjunct that has been shown to increase the duration of caudal analgesia by 3 to 4 hours without the added risk of nausea or neurotoxicity, but sedation is a common side effect.3,30,35,36 By excluding clonidine, we were able to study the blocks without the confounding sedative property of clonidine affecting only 1 arm. The lack of dosing/technique consensus among clonidine containing caudal regimens in recent studies demonstrates absence of the ideal dosing mix,3,30,31,35,36 further supporting our decision to exclude clonidine as a caudal additive. Importantly, since most of the difference in morphine consumption between our study groups occurred after the 12-hour mark, clonidine inclusion, with potential extension of duration from 4–6 to 8–10 hours, would not likely have influenced our observed outcomes. This point is supported by examination of the outcomes of a similar study by Tripi et al.,36 where clonidine was added to bupivacaine with epinephrine in a caudal block in patients undergoing ureteroneocystostomy. Our caudal study group compares favorably in morphine consumption (0.09 mg/kg over 24 hours) to those described in the study by Tripi et al.36 (0.11 mg/kg for the bupivacaine + epinephrine + clonidine group and 0.2 mg/kg for the bupivacaine + epinephrine group over 24 hours) utilizing very similar intraoperative and postoperative management.

The frequency of emesis was decreased in the TAPB group at 18 and 24 hours with statistical significance. This outcome most likely reflects the lower cumulative opioid dose required by that group. It is of note that an average difference of only 0.04 mg/kg of IV morphine was sufficient to produce an observable difference in emesis frequency, underscoring the importance of avoiding opiate additive to the caudal. The clinical importance of increased incidence of nausea and emesis was made evident by 2 patients in the caudal group who required an additional hospitalization day for poor oral intake (Table 1). The difference in incidence of emesis between the groups was not accompanied by other complications of opioids, such as respiratory depression or increased sedation, reflecting appropriate dosing of morphine for acute pain as assessed by our nursing staff.

Though 30% of patients across both groups required no narcotic during the study period, there was no difference between the 2 groups in time to first dose of narcotic or in likelihood to require any opioid. This rate was similar to the rate (5/18) observed by Tripi et al.36 in their bupivacaine-plus-clonidine group. The overall low opioid requirement and relatively low pain scores reflect the efficacy of a comprehensive multimodal pain management strategy including an effective regional technique, antispasmodic drug, and ketorolac on a scheduled basis. Because of the success of this pain management strategy, all but 2 patients who met surgical discharge criteria were discharged on postoperative day (POD) 1, a significant improvement over historical care of patients undergoing this operation. There were 6 patients who were not discharged on POD 1: 3 patients (2 TAPB, 1 caudal) were kept for foley catheter management and discharged on POD 2; 1 (TAPB) was kept for suprapubic drain management and discharged on POD 3; and 2 (both caudal) were kept for poor oral intake and achieved discharge on POD 2.

An important methodological note was our use of ultrasound guidance for all blocks in both groups and a predetermined end point for needle placement. Live verification of local anesthetic spread allowed us to minimize block failures. Though no formal sensory exam was conducted for fear of unblinding pain observers, no failures were diagnosed in the PACU postoperatively based on inadequate analgesia. Recent studies examined the impact of the location of the needle tip within the TAPB,37 with the more posterior placement associated with superior analgesic outcomes. The end point for needle placement within the TAPB was agreed upon by all investigators in our study before initiation, and aimed to reproduce the injection location of the original posterior landmark-based approach. This is a technical distinction which we believe contributed to the consistency and efficacy of the TAPB.

The above results, combined with the recognition of TAPB’s superior safety profile and wider applicability, lead us to recommend TAPB as a preferred method of postoperative analgesia for children undergoing ureteral reimplantation via lower abdominal incision.5,6,25 Our institution has adopted the TAPB as the preferred block along with a protocolized multimodal pain management strategy for the future care of children requiring ureteral reimplantation. Further study may focus on comparing TAPB with established regional anesthesia techniques for other abdominal and lower abdominal procedures to fully characterize the indications for TAPB.

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DISCLOSURES

Name: Robert B. Bryskin, MD.

Contribution: This author helped design and conduct the study, analyze the data, and prepare the manuscript.

Attestation: Robert B. Bryskin attests to the integrity of the original data and the analysis reported in this manuscript, and is the archival author and the principal investigator. Robert B. Bryskin approves the final manuscript and attests to having reviewed the original study data and data analysis.

Name: Bevan Londergan, MD.

Contribution: This author helped design and conduct the study, analyze the data, and prepare the manuscript.

Attestation: Bevan Londergan attests to the integrity of the original data and the analysis reported in this manuscript. Bevan Londergan approves the final manuscript and attests to having reviewed the original study data and data analysis.

Name: Rebekah Wheatley, MD.

Contribution: This author helped design and conduct the study, analyze the data, and prepare the manuscript.

Attestation: Rebekah Wheatley attests to the integrity of the original data and the analysis reported in this manuscript. Rebekah Wheatley approves the final manuscript and attests to having reviewed the original study data and data analysis.

Name: Renee Heng, MD.

Contribution: This author helped conduct the study, analyze the data, and prepare the manuscript.

Attestation: Renee Heng attests to the integrity of the original data and the analysis reported in this manuscript. Renee Heng approves the final manuscript and attests to having reviewed the original study data and data analysis.

Name: Marjorie Lewis, MD.

Contribution: This author helped design and conduct the study, analyze the data, and prepare the manuscript.

Attestation: Marjorie Lewis attests to the integrity of the original data and the analysis reported in this manuscript. Marjorie Lewis approves the final manuscript and attests to having reviewed the original study data and data analysis.

Name: Mark Barraza, MD.

Contribution: This author helped design the study and prepare the manuscript.

Attestation: Mark Barraza approves the final manuscript and attests to having reviewed the original study data and data analysis.

Name: Erica Mercer, MD.

Contribution: This author helped design the study and prepare the manuscript.

Attestation: Erica Mercer approves the final manuscript and attests to having reviewed the original study data and data analysis.

Name: Gang Ye, PhD.

Contribution: This author helped design the study, analyze the data, and prepare the manuscript.

Attestation: Gang Ye attests to the integrity of the original data and the analysis reported in this manuscript. Gang Ye approves the final manuscript and attests to having reviewed the original study data and data analysis.

This manuscript was handled by: James A. DiNardo, MD.

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