The Beneficial Effect of Transversus Abdominis Plane Block After

Society for Ambulatory Anesthesiology
Section Editor: Peter S. A. Glass
The Beneficial Effect of Transversus Abdominis Plane
Block After Laparoscopic Cholecystectomy in
Day-Case Surgery: A Randomized Clinical Trial
Pernille Lykke Petersen, MD,* Pia Stjernholm, MD,* Viggo B. Kristiansen, MD,† Henrik Torup, MD,‡
Egon G. Hansen, MD,‡ Anja U. Mitchell, MD,‡ Ann Moeller, MD,‡ Jacob Rosenberg, MD,§
Joergen B. Dahl, MD,! and Ole Mathiesen, MD¶
BACKGROUND: Laparoscopic cholecystectomy is associated with postoperative pain of moderate intensity in the early postoperative period. Recent randomized trials have demonstrated the
efficacy of transversus abdominis plane (TAP) block in providing postoperative analgesia after
abdominal surgery. We hypothesized that a TAP block may reduce pain while coughing and at rest
for the first 24 postoperative hours, opioid consumption, and opioid side effects in patients
undergoing laparoscopic cholecystectomy in day-case surgery.
METHODS: In this randomized, double-blind study, 80 patients undergoing laparoscopic cholecystectomy in our day-case surgery unit were allocated to receive either bilateral ultrasoundguided posterior TAP blocks (20 mL 0.5% ropivacaine) or placebo blocks. Postoperative pain
treatment consisted of oral acetaminophen 1000 mg ! 4, oral ibuprofen 400 mg ! 3, IV
morphine (0 –2 hours postoperatively), and oral ketobemidone (2–24 hours postoperatively). The
primary outcome was postoperative pain scores while coughing calculated as area under the
curve for the first 24 postoperative hours (AUC/24 h). Secondary outcomes were pain scores at
rest (AUC/24 h), opioid consumption, and side effects. Patients were assessed 0, 2, 4, 6, 8, and
24 hours postoperatively. Group-wise comparisons of visual analog scale (VAS) pain (AUC/24 h)
were performed with the 2-sample t test. Morphine and ketobemidone consumption were
compared with the Mann-Whitney test for unpaired data. Categorical data were analyzed using
the !2 test.
RESULTS: The primary outcome variable, VAS pain scores while coughing (AUC/24 h), was
significantly reduced in the TAP versus the placebo group (P " 0.04); group TAP: 26 mm (SD 13)
(weighted average level) versus group placebo: 34 (18) (95% confidence interval): 0.5–15 mm).
VAS pain scores at rest (AUC/24 h) showed no significant difference between groups. Median
morphine consumption (0 –2 hours postoperatively) was 7.5 mg (interquartile range: 5–10 mg)
in the placebo group compared with 5 mg (interquartile range: 0 –5 mg) in the TAP group (P #
0.001). The odds ratio of a random patient in group TAP having less morphine consumption than
a random patient in group placebo was P (group TAP # group placebo) " 0.26 (confidence
interval: 0.15, 0.37) where 0.5 represents no difference between groups. There were no
between-group differences in total ketobemidone consumption, levels of nausea and sedation,
number of patients vomiting, or consumption of ondansetron.
CONCLUSIONS: TAP block after laparoscopic cholecystectomy may have some beneficial effect
in reducing pain while coughing and on opioid requirements, but this effect is probably rather
small. (Anesth Analg 2012;115:527–33)
T
ransversus abdominis plane (TAP) block is a regional anesthetic technique that blocks neural afferents of the anterolateral abdominal wall. With the
aid of ultrasound (US) or anatomical landmark guidance,
local anesthetic is injected into the transversus abdominis
Author affiliations are provided at the end of the article.
Accepted for publication May 10, 2012.
Supported by the Department of Anaesthesia, Copenhagen University
Hospital, Glostrup, Denmark.
The authors declare no conflicts of interest.
Reprints will not be available from the authors.
Address correspondence to Pernille Lykke Petersen, MD, Department of
Acute Pain Management, Rigshospitalet, DK-2100 CPH, Copenhagen,
Denmark. Address e-mail to pernille.lykke.petersen@dadlnet.dk.
Copyright © 2012 International Anesthesia Research Society
DOI: 10.1213/ANE.0b013e318261f16e
September 2012 • Volume 115 • Number 3
fascial plane, where the nerves from T6 to L1 are located.
Randomized controlled trials have demonstrated the efficacy of a TAP block in providing postoperative analgesia
for up to 24 hours after abdominal surgery but mainly for
lower abdominal surgery.1– 8
Laparoscopic cholecystectomy is associated with postoperative pain of moderate intensity in the early postoperative period.9,10 Postoperative pain is most intense on
the day of surgery and the following day. For ambulatory surgical procedures, pain and other sequelae to
surgery and anesthesia may prevent same-day discharge.
Traditional treatment with opioids increases the likelihood of side effects such as nausea and sedation. A TAP
block, which may provide up to 24 hours of analgesia,
may therefore be an interesting analgesic option in this
population.
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527
Beneficial Effect of TAP Block After Laparoscopic Cholecystectomy
However, it has been questioned whether a TAP blockade at the umbilical level can provide analgesia in an upper
abdominal surgical procedure such as laparoscopic cholecystectomy.11 Two published trials with relatively few
patients (group size 18 and 21) have tested a TAP blockade
in this population. However, one trial suffered from an
unusual surgical access, because all laparoscopic ports
were below the umbilicus4 and the other from an insufficient description of both blinding as well as pain scores.8
Consequently, it remains to be clarified whether a TAP
block is a relevant analgesic treatment in this population
with upper abdominal surgery.
The aim of this prospective, double-blind, randomized,
placebo-controlled study was therefore to investigate the
effect of a TAP block on postoperative pain scores while
coughing calculated as area under the curve for the first 24
hours (AUC/24 h) (primary outcome), pain scores at rest
(AUC/24 h), opioid consumption, and opioid side effects
(secondary outcomes) in patients undergoing laparoscopic
cholecystectomy in day-case surgery.
METHODS
The study was performed at the Day-Case Surgery Unit at
Glostrup University Hospital, Copenhagen, Denmark. It
was conducted in compliance with guidelines for Good
Clinical Practice (GCP) and was monitored by the Copenhagen University Hospital GCP unit. Furthermore, the
design and the description of the study are in accordance
with the Consolidated Standards of Reporting Clinical
Trials.12 Approvals were obtained from the Regional Ethics
Committee, the Danish Medicine Agency, and the Danish
Data Protection Agency. The study was registered at www.
clinicaltrials.gov (NCT01046071) on January 8, 2010.
Participants
Adult patients (18 –75 years) with ASA physical status I to
III scheduled for laparoscopic cholecystectomy as day-case
surgery were included in the study. Exclusion criteria were
as follows: body mass index #18 or $35 kg/m2, inability to
understand Danish, relevant drug allergy, pregnancy, alcohol or drug abuse, daily opioid intake, consumption of pain
medications within 24 hours before surgery, and infection
at the injection site.
Patients received both written and oral information
regarding the trial. Signed informed consent was obtained
from all patients.
Routine Care
All patients received a standardized anesthetic regimen.
Anesthesia was induced with remifentanil 0.4 mL/kg/h
(0.6 mg/mL) and propofol. This was followed by the
insertion of an I-gel supraglottic airway (Intersurgical Inc.,
Lithuania). Anesthesia was maintained with propofol (variable rate) and remifentanil (fixed rate 0.4 mL/kg/h). Ten
minutes before the end of surgery, all patients received IV
sufentanil 0.2 "g/kg.
The laparoscopic procedure was achieved using 4 ports:
three 5-mm ports and one 10-mm port placed supraumbilically. Pneumoperitoneum was established with a Veress
needle technique; intraperitoneal pressure was maintained
at 12 mm Hg. The gallbladder was retracted via a port site
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cranial to the umbilicus. This port site was closed with
resorbable sutures in the fascia and all port sites were
closed with nonresorbable sutures in the skin.
A standardized postoperative analgesic regimen was
used consisting of oral acetaminophen 1000 mg every 6
hours and oral ibuprofen 400 mg every 6 hours, initiated 30
minutes before surgery. For the first 2 hours at the postoperative care unit, IV morphine was given by a nurse on
request of the patient. The initial morphine dose was 5 mg
and the following doses were 2.5 mg with a minimum of 10
minutes between doses. From 2 to 24 hours, oral ketobemidone 2.5 mg was taken based on the patient’s own decision
but with a minimum prescribed time interval between
doses of 1 hour. For nausea scores of at least moderate
intensity, ondansetron was given until discharge (first dose
4 mg IV followed by 1 mg IV).
Blinding and Randomization
The study was randomized, double-blind, and placebocontrolled. The patients were randomly assigned to receive
a TAP block with either 20 mL of ropivacaine 0.5% bilaterally (study group) or with 20 mL of isotonic saline 0.9%
bilaterally (placebo group).
Study medication was prepared by the hospital pharmacy into identical boxes containing either isotonic saline
or ropivacaine. The boxes were sealed and marked with the
name of the project, the investigators name, and consecutive numbers according to a computer-generated block
randomization list prepared by the hospital pharmacy
(block size " 10). A nurse (who was not part of the study or
who took care of the patient) opened the box and drew the
study medication into a neutral syringe. The patients, the
anesthesiologists, and staff providing postoperative care
were blinded to group assignments. Two of the investigators (PLP, PS) performed all assessments.
Interventions
A US-guided TAP block was performed bilaterally before
surgical incision by 1 of 2 investigators (PLP, PS). A US
probe (Venue 40; GE Healthcare,Waukesha, WI) was
placed transversely in the midaxillary line between the iliac
crest and the costal margin at the level of the umbilicus. The
external oblique, internal oblique, and transversus abdominis muscles and their fascia were visualized. A Pajunk
22-gauge, 80-mm needle (Medizintechnik, Geisingen, Germany) was introduced anteriorly and in the plane of the US
probe, and on entering the TAP, 2 mL of isotonic saline was
injected to verify the correct position of the needle. After
negative aspiration, 20 mL of the study solution was
injected and the injectate was seen spreading in the TAP as
a dark oval shape. Similarly, another TAP block was
performed on the contralateral side.
Outcomes
The primary outcome measure of the study was visual
analog scale (VAS) pain scores while coughing, estimated
as AUC/24 h based on pain scores at 0, 2, 4, 6, 8, and 24
hours postoperatively.
The secondary outcome measures of the study were
VAS pain scores at rest (AUC/24 h) based on pain scores at
0, 2, 4, 6, 8, and 24 hours postoperatively, morphine
ANESTHESIA & ANALGESIA
Assessed for eligibility (n=137)
Excluded (n=57)
Logistics (n=11)
Did not want to participate (n=17)
Inability to understand Danish (n=12)
Allergy to drugs used in study (n=7)
Pain medication within 24 hours (n=5)
BMI>35 (n=3)
Cannabis abuse (n=1)
Age > 75 years (n=1)
Randomized (n=80)
Allocated to placebo (n=40)
Allocated to TAP block (n=40)
Excluded (n=3)
Excluded (n=3)
Converted to open procedure (n=1)
Perforation of the intestine, 1 day hospitalization (n=1)
Intraoperative bleeding, 1 day hospitalization (n=1)
Converted to open procedure (n=1)
Severe dizziness, 1 day hospitalization (n=1)
Intraoperative bleeding, 1 day hospitalization (n=1)
Analyzed (n=37)
Analyzed (n=37)
Figure 1. Flow diagram of patient distribution. BMI " body mass index; TAP " transversus abdominis plane.
consumption 0 to 2 hours postoperatively, ketobemidone
consumption 2 to 24 hours postoperatively, levels of nausea
and sedation based on measurements at 0, 2, 4, 6, 8, and 24
hours postoperatively, number of vomiting episodes, and
number of patients vomiting during the first 24 postoperative hours.
Assessment of Outcomes
Before their operation, all patients were instructed in the
use of an ungraded 100-mm VAS with 0 " no pain and
100 " worst pain imaginable.
Patients were interviewed at 0, 2, 4, 6, 8, and 24 hours
after operation by the investigators either in person or by
telephone after discharge. The investigators recorded the
patients’ assessments of VAS pain scores at rest and while
coughing, opioid consumption, and the patients’ assessments of opioid side effect at each interview.
Opioid consumption was recorded as on-request IV
morphine (mg) for the first 2 hours postoperatively and
oral ketobemidone (mg) taken by the patients 2 to 24 hours
postoperatively.
The severity of both nausea and sedation was assessed
by patients on a 4-point scale (none, mild, moderate, and
severe). The number of episodes of vomiting ($10 mL)
postoperatively at 0 –2, 2– 4, 4 – 6, 6 – 8, and 8 –24 hours was
reported by the patients. Finally, the number of patients
receiving ondansetron was recorded.
Sample Size
We were not able to find any study in laparoscopic
cholecystectomy that used VAS pain scores calculated as
area under the curve. Therefore, we based our sample size
calculation on the highest postoperative VAS score (at 6
hours postoperatively) from a previous study conducted at
September 2012 • Volume 115 • Number 3
our day-case surgical unit.13 The anticipated VAS score at 6
hours postoperatively was 50 (SD 25). We considered a 40%
reduction in VAS pain scores to be of clinical relevance.
With a type I error of 0.05 and a type II error of 0.10, a
sample size calculation determined that 68 patients were
needed in the study. To allow for dropouts and exclusions,
we recruited an additional 12 patients for the study.
Statistical Methods
Statistical analyses were performed using SPSS 19 (SPSS
Inc., Chicago, IL) and SAS 9.1 (SAS Institute Inc., Cary, NC,
USA). Data are presented as median and interquartile
range (IQR) or with mean and SD as appropriate. The
Kolmogorov-Smirnov (K-S) test with Lilliefors significance
correction was used to test for normality. VAS pain scores
at rest and while coughing were calculated as AUC/24 h.
VAS pain scores at rest AUC/24 h (K-S: P " 0.20), VAS pain
scores while coughing AUC/24 h (K-S: P " 0.20), and pain
scores while coughing at 6 hours (K-S: P " 0.094) followed
the normal distribution and were compared with the
Student t test with unequal variances. Morphine consumption (K-S: P # 0.001) and ketobemidone consumption (K-S:
P # 0.001) did not follow a normal distribution and were
compared with the Mann-Whitney (M-W) test for unpaired
data, and confidence intervals (CIs) were calculated for P
(X # Y) using Wilcoxon-Mann-Whitney odds analysis.1a
Number of patients vomiting and using ondansetron was
analyzed using the !2 test. For comparing side effects
(nausea and sedation), numerical values were assigned to
the scores from each patient (none " 0, slight " 1, moderate " 2, and severe " 3). Data for sedation (K-S: P # 0.001)
a
Available at: http://www2.sas.com/proceedings/sugi31/209-31.pdf. Accessed April 30, 2012.
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529
Beneficial Effect of TAP Block After Laparoscopic Cholecystectomy
and nausea (K-S: P # 0.001) did not follow a normal
distribution and were compared with the M-W test. P #
0.05 was considered statistically significant.
RESULTS
One hundred thirty-six patients were approached for participation in the study from April 2010 to February 2011.
Eighty patients were recruited and randomly assigned to
their treatment group. However, 6 patients were later
excluded resulting in 74 patients in the final analyses
(Fig. 1).
All US-guided TAP blocks were performed as described
in the Methods section and without any complications.
Patients’ characteristics and perioperative data are depicted
in Table 1; there were no large differences between groups.
Primary End Point
The primary outcome variable, VAS pain scores while
coughing, estimated as AUC/24 h, was significantly reduced in group TAP: 26 mm (SD 13) (weighted average
level) versus group placebo: 34 (18) (95% CI: 0.5–15 mm)
Table 1. Baseline Patient Characteristics and
Perioperative Data
No. of patients
Sex (female/male) (n)
Age (y)
Height (cm)
Weight (kg)
Duration of surgery (min)
Volume of isotonic sodium chloride (mL)
Propofol (mg)
Remifentanil (mg)
Sufentanil ("g)
TAP
group
37
28/9
42 (13.5)
171 (9.4)
77 (14.5)
73 (31.5)
659 (262)
681 (169)
2.8 (1.0)
15.3 (2.8)
Placebo
group
37
25/12
43 (17.0)
170 (9.4)
76 (13.8)
62 (18.3)
644 (223)
683 (142)
2.4 (0.7)
15.7 (3.5)
Data are presented as mean (SD) or number.
TAP " transversus abdominis plane.
(P " 0.04). VAS pain scores while coughing at each time
point assessed are presented in Figure 2.
Correlation analysis demonstrated a positive relationship between the 24-hour AUC based on VAS pain scores
while coughing (primary outcome), morphine consumption, and ketobemidone consumption in both groups.
Spearman correlation (#) for morphine was 0.370 (95% CI:
0.075– 0.639) in the TAP block group and 0.501 (95% CI:
0.176 – 0.734) in the placebo group. Correlations for ketobemidone consumption were # " 0408 (95% CI: 0.131– 0.650)
in the TAP block group and # " 0.684 (95% CI: 0.448 – 0.828)
in the placebo group. Correlation analysis demonstrated a
positive correlation between the 24-hour AUC based on
VAS pain scores while coughing and number of vomiting
episodes; # " 0.467 (95% CI: 0.178 – 0.710) in the placebo
group only (Fig. 3).
Secondary End Points
Pain Scores
For the 24-hour AUC based on VAS pain scores at rest, no
significant difference between treatment groups was demonstrated (group TAP 19 [10] versus group placebo 23 [13]
[P " 0.16]). VAS pain scores at rest at each time point are
presented in Figure 4.
Our sample size calculation was based on VAS pain
scores at 6 hours postoperatively because we did not find
any study in laparoscopic cholecystectomy that used VAS
pain scores calculated as area under the curve. VAS pain
scores while coughing at 6 hours were not significantly
reduced in the TAP group, 26 mm (SD 19), compared with
the placebo group, 34 mm (SD 19) (95% CI: %0.2 to 18 mm)
(P " 0.05).
Opioid Consumption
Median morphine consumption (0 –2 hours postoperatively) was 7.5 mg (IQR: 5–10 mg) in the placebo group
compared with 5 mg (IQR: 0 –5 mg) in the TAP group (P #
0.001). The odds ratio of a random patient in group TAP
having less morphine consumption than a random patient
in group placebo was P (group TAP # group placebo) "
0.26 (CI: 0.15, 0.37) where 0.5 represents no difference
between groups. There was no significant difference between groups for total ketobemidone consumption 2 to 24
hours postoperatively. Median ketobemidone consumption
was 0 mg (0 –2.5 mg) in the TAP group compared with 2.5
mg (0 –5 mg) in the placebo group (P [group TAP # group
placebo]) " 0.42 [CI: 0.30 – 0.53]).
Side Effects
Levels of sedation, nausea, number of patients vomiting,
number of vomiting episodes, and consumption of ondansetron were not significantly different between groups
(Table 2).
DISCUSSION
Figure 2. Visual analog scale (VAS) pain scores (mean and SD) while
coughing in group TAP versus group placebo at 0 to 24 hours
postoperatively. VAS pain scores (weighted mean AUC/24 h) while
coughing were significantly reduced in group TAP (26 mm [13])
versus group placebo (34 mm [18]) (P " 0.04). TAP " transversus
abdominis plane.
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In this study, we have demonstrated that the application of
a TAP block with 20 mL of ropivacaine 0.5% bilaterally in
patients undergoing day-case laparoscopic cholecystectomy resulted in reduced pain scores during coughing
calculated as the area under the curve for the first 24 hours
postoperatively, and reduced morphine consumption in
ANESTHESIA & ANALGESIA
Figure 3. Scatter plots of visual analog scale (VAS) pain scores (weighted mean AUC/24 h) while coughing with morphine consumption 0 to
2 hours (# " 0.501 [placebo], # " 0.370 [TAP]), ketobemidone consumption 2 to 24 hours (# " 0.684 [placebo], # " 0.408 [TAP]), and
number of vomiting episodes (# " 0.467 [placebo], no correlation in the TAP group). # " Spearman correlation coefficient; TAP " transversus
abdominis plane.
Table 2. Postoperative Nausea, Vomiting,
and Sedation
TAP
group
(n ! 37)
Figure 4. Visual analog scale (VAS) pain scores (mean and SD) at
rest in group TAP versus group placebo. VAS pain scores (AUC/24 h)
at rest were not significantly reduced in group TAP versus group
placebo. TAP " transversus abdominis plane.
the first 2 postoperative hours. Furthermore, we observed a
positive correlation between the highest pain scores while
coughing and consumption of morphine and ketobemidone, which supports the primary outcome finding. However, because of large CIs on the difference between
groups, the true benefit of a TAP block in laparoscopic
cholecystectomy may be small.
The overall 24-hour reduction in pain scores while
coughing in the TAP group was primarily attributable to
reduced VAS scores from 0 to 8 hours postoperatively. In
our pretrial sample size calculation, we considered a
20-mm reduction in pain scores to be of clinical relevance. The actual 24-hour AUC-VAS pain was reduced
from 35 to 26 mm, which is 9 mm on the VAS. The
reduction may be considered clinically relevant, because
most VAS scores at all time points in the treatment group
were reduced from moderate ($30 mm) to low pain (#30
mm) (Fig. 2). Furthermore, the clinical significance of reduced
pain scores has been addressed in 2 previous trials in an
emergency department population in which a reduction of 9
mm14 and 13 mm,15 respectively, could be considered clinically relevant, and did not vary with gender, age, or cause of
pain.14 These findings support the clinical relevance of the
September 2012 • Volume 115 • Number 3
Postoperative nausea scores
0h
2h
4h
6h
8h
24 h
No. of patients vomiting/24 h
No. of patients requiring
ondansetron/24 h
Postoperative sedation scores
0h
2h
4h
6h
8h
24 h
Placebo
group
(n ! 37)
0
0
0
0
0
0
(0–1)
(0–3)
(0–3)
(0–2)
(0–2)
(0–2)
8
23
0
0
0
0
0
0
(0–2)
(0–3)
(0–2)
(0–3)
(0–1)
(0–2)
13
23
3
2
1
1
1
0
(1–3)
(0–3)
(0–3)
(0–3)
(0–3)
(0–2)
3
2
1
1
1
0
(1–3)
(0–3)
(0–3)
(0–3)
(0–2)
(0–2)
Data are presented as median (range) or number.
TAP " transversus abdominis plane.
results of the present study. However, the minimally relevant
reduction in pain score is controversial.16,17
We did not find a significant difference in pain scores at
rest between groups, but pain scores at rest were generally
low (#30 mm) and therefore the study had low sensitivity
to detect a difference on this point.18,19
Morphine consumption was significantly reduced from
0 to 2 hours postoperatively, thereby supporting the analgesic effect of the TAP. However, the actual reduction in
morphine consumption was low and most likely of no
clinical relevance. In general, ketobemidone consumption
from 2 to 24 hours was low and we did not find any
significant difference between groups. This was not surprising, because a previous study demonstrated low opioid
consumption after laparoscopic cholecystectomy.10 The
present study would therefore be expected to have low
sensitivity to demonstrate any difference on this outcome.
Consequently, we chose pain scores while coughing as our
primary outcome measure in the study.
Previously, 2 randomized controlled studies have demonstrated analgesic efficacy of TAP blockade after laparoscopic cholecystectomy.4,8 Unfortunately, both studies had
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Beneficial Effect of TAP Block After Laparoscopic Cholecystectomy
methodological limitations. El-Dawlatly et al.4 demonstrated a significant reduction in perioperative sufentanil
administration as well as 24-hour morphine consumption
with a TAP block. Regrettably, neither pain scores nor side
effects were assessed in the study. All ports for the laparoscopic procedure were below the umbilicus. Therefore, the
study does not adequately answer the question of whether
a TAP block is advantageous for laparoscopic cholecystectomy with incision holes in the upper abdominal area, as is
most frequently used. Ra et al.8 demonstrated a reduced
use of both ketorolac and fentanyl after administration of a
TAP block. Furthermore, pain scores in the treatment group
were significantly reduced for 24 hours in their study.
However, the study suffers from an insufficient description
of randomization and blinding, and it was not stated
whether the evaluation of pain scores was conducted at rest
or during mobilization.
We compared a TAP block to a placebo block; therefore,
we cannot comment on the TAP block analgesic effect
compared with that of a local anesthetic infiltration into the
abdominal port hole wounds. Local anesthetic infiltration
has an expected duration of 0 to 6 hours,20 and although we
found a reduced 24-hour AUC pain score with the TAP
block, this result is primarily based on reduced pain scores
during the first 8 postoperative hours. Three systematic
reviews concluded that local anesthetics have a significant
benefit after laparoscopic cholecystectomy, but the effect is
small and of doubtful clinical relevance.20 –22 Furthermore,
a recently published, randomized, clinical trial did not find
any effect of combined subcutaneous and intraperitoneal
installation of levobupivacaine on postoperative pain after
laparoscopic cholecystectomy.23
Pain scores in our placebo group were low. Therefore, it
can be argued that performing a TAP block may be unnecessary in relation to the pain levels and that port infiltration with
local anesthetic in combination with a multimodal analgesic
treatment may be a better choice. In a multimodal approach,
dexamethasone (8 mg) may have a role; 2 clinical studies have
demonstrated a positive effect on pain, nausea, and recovery
after laparoscopic cholecystectomy.9,24
There are a number of limitations to this study. First,
despite block performance with real-time US, we do not
know whether all TAP blocks produced a sensory block,
because we did not make sensory assessments in order not
to unblind the study. Even if a third and independent
investigator had tested the sensory levels of the TAP
blockade, this would have unblinded the patients and
thereby influenced the results of the study. Furthermore,
assessment of sensory levels does not necessarily reflect the
analgesic effectiveness of the TAP blockade. This is more
truly reflected in differences in pain scores or opioid
consumption. Second, we have no assessment points from
8 to 24 hours postoperatively. We thought that it was
important to document an effect in the early postoperative
period, when pain levels are highest. Third, we used the
US-guided posterior approach at the umbilical level to
perform the TAP block, but this approach may not produce
sensory block above the umbilicus.25 We might have
achieved better coverage of the upper port holes for
the laparoscopic procedure with a subcostal approach to
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the TAP block.26 Fourth, we did not encounter any complications with the TAP block, but complications are rare and
our study was underpowered to detect complications.
Fifth, port infiltration after laparoscopic cholecystectomy is
a standard procedure in many surgical departments. We
considered port infiltration as part of the basic analgesic
treatment in both study groups, but we discarded this
approach in order not to exceed the toxic limit for ropivacaine because surgeons at our institution used up to 50 mL
of a local anesthetic for infiltration.
It should be considered whether a TAP block is relevant in
the present surgical population. The reduction in pain score
from moderate to low while coughing has to be weighed
against the cost of a TAP blockade, procedural time (low in
experienced hands), and the risk of procedural visceral perforation (low with a US-guided procedure). Finally, because
the general improvement in pain scores was approximately 10
to 15 mm on the VAS, it cannot be excluded that a more
comprehensive oral multimodal analgesic treatment that includes, e.g., gabapentinoids and glucocorticoids in addition to
acetaminophen and nonsteroidal antiinflammatory drugs,
will outweigh the benefits of a TAP blockade. Future trials
will have to address these questions.
In conclusion, our study showed that patients who
received TAP block in addition to a basic analgesic regimen
with acetaminophen and ibuprofen after laparoscopic cholecystectomy had reduced pain scores (AUC/24 h) while
coughing as well as reduced morphine consumption in the
first 2 postoperative hours, but these reductions were
rather small. The procedure was without reported complications and may be considered as part of multimodal
analgesic treatment for laparoscopic cholecystectomy in
day-case surgery. However, the additional analgesic effect
of a TAP block in the presence of a vigorous multimodal
analgesic regimen should be further explored.
AUTHOR AFFILIATIONS
From the *Department of Anaesthesia, Copenhagen University
Hospital, Glostrup; Departments of †Surgical Gastroenterology, ‡Anaesthesiology, and §Surgery, Copenhagen University
Hospital, Herlev; !Department of Anaesthesia, Centre of Head
and Orthopaedics, Copenhagen University Hospital, Rigshospitalet, Copenhagen; and ¶Section of Acute Pain Management,
Copenhagen University Hospital, Rigshospitalet, Copenhagen,
Denmark.
DISCLOSURES
Name: Pernille Lykke Petersen, MD.
Contribution: This author helped design the study, conduct
the study, analyze the data, and write the manuscript.
Attestation: Pernille Lykke Petersen has seen the original
study data, reviewed the analysis of the data, approved the
final manuscript, and is the author responsible for archiving
the study files.
Name: Pia Stjernholm, MD.
Contribution: This author helped design the study, conduct
the study, and write the manuscript.
Attestation: Pia Stjernholm approved the final manuscript.
Name: Viggo B. Kristiansen, MD.
Contribution: This author helped design the study and write
the manuscript.
Attestation: Viggo B. Kristiansen approved the final manuscript.
ANESTHESIA & ANALGESIA
Name: Henrik Torup, MD.
Contribution: This author helped design the study and write
the manuscript.
Attestation: Henrik Torup approved the final manuscript.
Name: Egon G. Hansen, MD.
Contribution: This author helped design the study.
Attestation: Egon G. Hansen approved the final manuscript.
Name: Anja U. Mitchell, MD.
Contribution: This author helped design the study.
Attestation: Anja U. Mitchell approved the final manuscript.
Name: Ann Moeller, MD.
Contribution: This author helped design the study.
Attestation: Ann Moeller approved the final manuscript.
Name: Jacob Rosenberg, MD.
Contribution: This author helped design the study and write
the manuscript.
Attestation: Jacob Rosenberg approved the final manuscript.
Name: Joergen B. Dahl, MD.
Contribution: This author helped design the study, conduct
the study, analyze the data, and write the manuscript.
Attestation: Joergen B. Dahl has seen the original study data,
reviewed the analysis of the data, and approved the final
manuscript.
Name: Ole Mathiesen, MD.
Contribution: This author helped design the study, conduct
the study, analyze the data, and write the manuscript.
Attestation: Ole Mathiesen has seen the original study data,
reviewed the analysis of the data, and approved the final
manuscript.
This manuscript was handled by: Peter S. A. Glass, MB ChB,
FFA (SA).
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