Volume 74, No.4: 2022 Siriraj Medical Journal

https://he02.tci-thaijo.org/index.php/sirirajmedj/index

233

Original Article

SMJ

Chatporn Boonyapalanant, M.D.**, Varat Woranisarakul, M.D.*, Siros Jitpraphai, M.D.*, Ekkarin Chotikawanich,

M.D.*, Tawatchai Taweemonkongsap, M.D.*, Hari Bahadur KC, M.D.***, itipat Hansomwong, M.D.*

*Division of Urology, Department of Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, ailand, **Division of Urology,

Department of Surgery, Faculty of Medicine, Panyananthaphikkhu Chonprathan Medical Center, Srinakharinwirot University, Nonthaburi, ailand,

***Department of Surgery, Pokhara Academy of Health Sciences, Nepal.

The Efcacy of Inside-Out Transversus Abdominis

Plane Block vs Local Inltration before Wound

Closure in Pain Management after Kidney

Transplantation: A Double-blind, Randomized Trial

ABSTRACT

Objective: Transversus abdominis plane (TAP) block is a form of multimodal pain management in open abdominal

surgery. Among patients who undergo kidney transplantation, their choice of painkillers is limited. is study

aims to determine the ecacy of TAP block vs local inltration in pain management aer kidney transplantation.

Materials and Methods: In this prospective, randomized, double-blinded clinical trial, 46 patients with end-stage

kidney disease who had undergone kidney transplantation were randomly divided into two groups: a local anesthetic

inltration (LA) group receiving 0.25% Bupivacaine 20 ml around the surgical wound before wound closure and a

TAP block group receiving 0.25% Bupivacaine 20 ml by the inside-out technique. eir postoperative pain scores

and morphine consumption were recorded at 2, 6, 12, 18, 24, and 48 hours.

Results: ere was no statistically signicant dierence in the baseline characteristics between the groups. e

postoperative pain score at two hours in the TAP block group was signicantly lower than in the LA group

(P value = 0.037), but without other dierences in their pain scores aer two hours. ere was no statistical dierence

in the morphine consumption between the two groups. e total morphine consumption in the TAP block group

was less than in the LA group, but this was not statistically signicant. No patients suered from complications of

the TAP block.

Conclusion: Transversus abdominis plane block can reduce postoperative pain at two hours aer kidney transplantation,

without signicant complications.

Keywords: Transversus abdominis plane block; kidney transplantation; pain management; postoperative pain

(Siriraj Med J 2022; 74: 233-238)

Corresponding author: itipat Hansomwong

E-mail: thitipat.han@mahidol.ac.th

Received 7 September 2021 Revised 1 February 2022 Accepted 17 February 2022

ORCID ID: https://orcid.org/ 0000-0002-8243-7876

http://dx.doi.org/10.33192/Smj.2022.29

Abbreviations

TAP Transversus abdominis plane

NRS Numerical rating scale

BMI Body mass index

LA Local anesthesia

QL Quadratus lumborum

Volume 74, No.4: 2022 Siriraj Medical Journal

https://he02.tci-thaijo.org/index.php/sirirajmedj/index

234

INTRODUCTION

Kidney transplantation is the treatment of choice

in patients with end-stage kidney disease. A kidney

transplant is a major operation requiring a classical

incision at the lower abdomen, extending from laterally

to the pubic symphysis to the anterior superior iliac crest

called Gibson incision. Many patients require a painkiller

aer the operation, and postoperative pain control is

crucial to improving one’s surgical outcome. Multimodal

analgesia aims to decrease opioid consumption and its side

eects. Especially among patients who undergo kidney

transplantation, their choice of painkiller is limited, due

to any such drugs’ interaction with immunosuppressive

drugs and nephrotoxicity.

Local anesthesia inltration

around the incision is one of the traditional methods of

local pain control. Two decades ago, transversus abdominis

plane (TAP) block was introduced as a new technique to

reduce postoperative pain. is was originally reported by

Ra in 2001.

TAP block is a regional anesthesia, targeting

sensory nerves running between the internal oblique

muscle and the transversus abdominis muscle layer, these

nerves receiving signal from anterior abdominal wall

between level of T9 and T12 via a blinded technique or

ultrasound guidance.

3,4

A TAP block can be performed

by a surgeon or anesthesiologist using the outside-in

technique aer the induction of anesthesia or through

the inside-out technique before the wound is closed. A

TAP block has been used to control postoperative pain

involving many kinds of abdominal surgery. e results

from many trials have produced variable outcomes, some

showing no signicant dierence in post-operative pain

management, while others have resulted in signicant pain

scores and/or opioid consumption.

5-11

According to meta-

analyses, the TAP block seems to benet postoperative

pain control in kidney transplantation patients.

Until

now, there has been no report comparing traditional,

local anesthetic inltration with the TAP block by the

inside-out technique in kidney transplantation patients.

is study aims to determine the ecacy of the TAP

block vs local inltration in pain management aer

kidney transplantation.

MATERIALS AND METHODS

This prospective, randomized, double-blinded

clinical trial was approved by the Ethics Committee

of the Faculty of Medicine Siriraj Hospital, Mahidol

University, ailand, protocol number 826/2019(IRB4).

Aer informed consent, 46 patients with end-stage kidney

disease who had undergone kidney transplantation from

both living-donor and cadaveric kidney transplant at

Siriraj Hospital were recruited. Patients were excluded

if they had a history of painkiller allergy, if they could

not dene a pain score in the numerical rating scale

(NRS), were suspected of having a painkiller addiction

or an abnormal coagulopathy, or had incomplete data.

Patients’ demographic data (sex, age, BMI, and

previous abdominal surgery); intraoperative data (operative

time and length of wound); and postoperative data

covering 48 hours (pain score and opioid usage) were

collected. Patients were randomly divided into two groups:

a local anesthetic inltration (LA) group and a TAP

block group. e group allocations were concealed in

opaque envelops which were randomly picked up and

opened just before each wound was closed. Aer standard

monitoring, all patients received general anesthesia. e

kidney transplantation was then done routinely. In the

LA group, patients received 0.25% Bupivacaine 20 ml

around the surgical wound before the wound was closed.

In the TAP block group, the TAP block was performed

by a surgeon with the ultrasound- guided inside-out

technique. A curvilinear ultrasound probe was placed

just lateral to the quadratus lumborum muscle above

the iliac crest as high as possible via a standard Gibson

incision. Aer the layer between the internal oblique

muscle and the transversus abdominis muscle was found,

0.25% Bupivacaine 20 ml was injected into the space

via needle 25-gauge 1.5 inch with the appearance of a

Goose egg sign before the wound was closed (Fig 1). All

patients were received postoperative care and pain control

at postanesthesia care unit following Siriraj protocol

including Acetaminophen 500 mg 1 tab per oral every

6 hours for 3 days. Aer the operation, patients were

assessed on a pain score with a numerical rating scale

Fig 1. TAP block procedure

0.25% Bupivacaine 20 ml was injected

into the space between the internal oblique

muscle and the transversus abdominis

muscle via needle 25-gauge 1.5 inch

with ultrasound guided.

Boonyapalanant et al.

Volume 74, No.4: 2022 Siriraj Medical Journal

https://he02.tci-thaijo.org/index.php/sirirajmedj/index

235

Original Article

SMJ

(NRS) (0=no pain, 10=worst possible pain) at 2, 6, 12,

18, 24, and 48 hours. If the pain score was more than

3 or analgesics were required, 1 mg of morphine was

intravenously administered, and then the pain score was

rechecked aer ve minutes. e amount of morphine

consumption was recorded. All pain scores and morphine

consumption were recorded by investigators who were

blinded to the group allocations.

e goal was to compare the pain score and morphine

consumption aer the TAP block and LA technique.

e sample size was calculated from previous study on

TAP-block ecacy.

9-11

Statistical analysis was conducted

using SPSS version 21 soware. Demographic data and

intraoperative data were present as mean ± SD. In a

normal distribution of data, the Student’s t-test and

Pearson’s chi-square were used to compare the results

between the two groups. e postoperative pain scores

and morphine consumption were present as a median

with IQR, and compared between the groups by using

the Mann-Whitney U test. A P value less than 0.05 was

determined as having statistical signicance.

RESULTS

From January, 2020 to November, 2020, 46 patients

were enrolled in this study and were randomized into

two groups, with 23 people in each group. One patient

in the TAP block group was excluded due to the need for

reoperation within 24 hours because of bleeding from

tissue around the kidney gra (Fig 2). 62.2% of the study

population was male, and the mean age was 46.7 years

old (range: 26 – 62). e mean body mass index was

21.39 kg/m

(range: 15.6 – 27.9). 28.9% of the patients

had previous abdominal surgery. e mean operative

time was 177 minutes (range: 110 – 360) and the mean

length of the wound was 16.6 centimeters (range: 12 –

23). ere was no statistically signicant dierence in

the baseline characteristics between the groups, as is

indicated in Table 1.

The pain scores (NRS) were compared in two

groups, (as seen in Fig 3), at 2, 6, 12, 18, 24, and 48 hours

postoperatively. e median and IQR of pain scores at

2, 6, 12, 18, 24, and 48 hours in LA group are 3 (3-4),

2 (1-3), 2 (0-3), 1 (0-2), 0 (0-1) and 0 (0) respectively.

Fig 2. Patients ow chart.

TABLE 1. Comparison of two outow reconstruction techniques among the study patients.

LA group TAP block group P value

Sex   0.848

 Male 60.9% 63.6%

 Female 39.1% 36.4%

Age(years) 48.4±9.7 44.9±10.2 0.247

Bodymassindex 21.8±3.1 20.9±2.8 0.339

Previousabdominalsurgery 30.4% 27.3% 0.815

Operativetime(minute) 181.8±50.1 172.5±36.9 0.484

Lengthofwound(cm) 16.5±2.2 16.7±2.3 0.771

Volume 74, No.4: 2022 Siriraj Medical Journal

https://he02.tci-thaijo.org/index.php/sirirajmedj/index

236

e median and IQR of pain scores at 2, 6, 12, 18, 24,

and 48 hours in TAP block group are 2 (2-3), 2 (1-2),

2 (1-2), 0 (0-1), 0 (0-0.25) and 0 (0). e postoperative

pain score at two hours in the LA group was higher than

in the TAP block group (P value = 0.037), though there

were no other dierences in the pain scores aer two

hours and throughout a 48-hour period.

ere was no statistical dierence in morphine

consumption between the groups, in terms of total usage,

and any recorded time point, as shown in Fig 4. e

median total morphine consumption in the LA group

was 2 mg (IQR 1-4); in the TAP block group, it was 1 mg

(IQR 1-3), with a p value of 0.105. No patients suered

from complications of the TAP block.

DISCUSSION

e most eective options for postoperative pain

control aer kidney transplantation are not always easily

determined, due to the many limitations arising from

patients’ status. In post-kidney transplant patients, many

kinds of painkillers have a risk of causing nephrotoxicity

and can alter renal clearance. An epidural block is an option

for postoperative pain control in abdominal surgery, but

there is risk of epidural hematoma formation in kidney

transplantation patients because of platelet dysfunction.

Regional nerve block has become a promising choice for

postoperative pain control in kidney transplant patients.

Regional nerve block or TAP block is target on specic

sensory nerve but local anesthesia can be variable due to

Fig 3. Postoperative pain score (NRS) at 2, 6, 12, 18, 24, and 48 hours postoperatively (median with IQR).

Fig 4. Morphine consumption at 2, 6, 12, 18, 24, and 48 hours postoperatively (median with IQR).

Boonyapalanant et al.

Volume 74, No.4: 2022 Siriraj Medical Journal

https://he02.tci-thaijo.org/index.php/sirirajmedj/index

237

Original Article

SMJ

operator dependent and variations of anatomy.

From

a meta-analysis

, we see that a TAP block can reduce

total opioid consumption (morphine consumption to

6 mg per day) as well as a patient’s pain score within 24

hours aer the operation. Our study shows that the pain

scores two hours aer the operation in the TAP block

group were lower than in the LA group, but, again, there

was no signicant dierence between the groups aer

that. Our LA group were given 0.25% Bupivacaine 20 ml

around the surgical wound, which can also reduce the

postoperative pain scores and morphine consumption.

Even though our study had local pain control in the LA

group, the results still reveal that the TAP block was better

than the LA, as regards post-operative pain control aer

kidney transplantation. TAP block is recommended

if ultrasound is available and patients do not have an

abnormal coagulopathy.

Concerning the duration of pain control aer the

TAP block, our meta-analysis

showed that 0.375%,

0.5% and 0.75% Ropivacaine TAP block reduced the

pain score at two hours aer surgery, but only 0.75%

Ropivacaine was eective 12 to 24 hours aer surgery.

We used 0.25% Bupivacaine 20 ml for the TAP block.

Onset of action of 0.25% Bupivacaine is about 19 ± 41

seconds and duration of action is about 7.02 ± 1.46 hours

aer injection.

is may be one of the reasons why there

were signicantly reduced pain scores only at two hours

aer the operation. In some studies, specialists added

drug regimens to the TAP block in order to prolong

the pain-control eect. Yang et al.

have shown that

the addition of dexmedetomidine can provide a more

eective analgesic eect for the TAP block. Systematic

review and meta-analysis from Choi et al.

have indicated

that adding dexamethasone to the local nerve block can

prolong the eect of nerve block more than by just doing

a local nerve block alone.

In a meta-analysis

, some of researchers used the

blinded technique of the TAP block, but many used the

ultrasound-guided approach. e ecacy of the latter has

been shown to be superior. Today, the ultrasound-guided

technique is considered the gold standard for the TAP

block.

Regarding the other technique of TAP block in our

study, we used the ultrasound-guided method with the

inside-out technique. e typical outside-in TAP block

technique may cause visceral organ damage, even if the

procedure is ultrasound-guided.

19,20

e inside-out technique

can reduce the possibility of visceral organ damage due

to performers’ visualization while performing the TAP

block. Additionally, the TAP block, which is performed

by a surgeon intra-operatively, requires less time than

the conventional TAP block by an anesthesiologist, and

there is with no dierence in the postoperative pain-

control outcomes.

ere is an important question involving the timing

of the administration of the TAP block. In our study, the

TAP block was applied before the wound was closed,

though some performers do this before starting to operate.

Dahl et al.

have demonstrated that postoperative pain

scores were not signicantly dierent between the pre- and

post-incisional nerve block. Another technique that may

help in pain management for kidney transplant patients

is the quadratus lumborum (QL) block 2. According to

Kolacz et al.

, this kind of block can reduce fentanyl

consumption within 24 hours aer kidney transplantation,

without a dierence in the pain score, compared to the

TAP block. Given the inside-out technique used in our

study, we may also perform a QL block via a kidney-

transplantation incision.

ere were a number of limitations in this study.

First, we could not assess the patients’ sensory-distribution

level because the TAP block was performed before the

wound was closed and while patients were still under

general anesthesia. Secondly, our inside-out technique is

dierent from original TAP technique. e double pop

sensation described in original technique cannot be felt

during needle passage, so ultrasound guided is necessary

to determine the depth of the needle. e third limitation

is no use of intravenous patient control analgesia to

access accurate dose of morphine requirement. Lastly,

our sample size was too small to broadly assess the safety

of the TAP block technique. Further studies are required

to compare the safety of the inside-out method with the

outside-in technique of the TAP block, and to determine

the optimum dose or volume to use for the TAP block.

CONCLUSION

e transversus abdominis plane block can reduce

postoperative pain aer kidney transplantation, without

signicant complications. We conclude that the TAP block

can be used as a part of multimodal pain management

for post-kidney transplantation patients.

Conicts of interest statement: e authors declare

that there are no nancial or other conicts of interest

involved in this project.

REFERENCES

1. Baker M, Perazella MA. NSAIDs in CKD: Are ey Safe? Am

J Kidney Dis. 2020; 76(4):546-57.

2. Ra AN. Abdominal eld block: A new approach via the

lumbar triangle. Anaesthesia. 2001;56(10):1024-26.

3. Tsai HC, Yoshida T, Chuang TY, Yang SF, Chang CC, Yao

HY, et al. Transversus Abdominis Plane Block: An Updated Review

Volume 74, No.4: 2022 Siriraj Medical Journal

https://he02.tci-thaijo.org/index.php/sirirajmedj/index

238

of Anatomy and Techniques. Biomed Res Int. 2017;2017:8284363.

4. Hopkin PM. Ultrasound guidance as a gold standard in regional

anaesthesia. Br J Anaesth. 2007;98(3):299-301.

5. Shin HJ, Kim ST, Yim KH, Lee HS, Sim JH, Shin YD. Preemptive

analgesic ecacy of ultrasound-guided transversus abdominis

plane block in patients undergoing gynecologic surgery via

a transverse lower abdominal skin incision. Korean J Anesthesiol.

2011;61(5):413-8.

6. Gharaei H, Imani F, Almasi F, Solimani M. e Eect of

Ultrasound-guided TAPB on Pain Management aer Total

Abdominal Hysterectomy. Korean J Pain. 2013;26(4):374-8.

7. Chang H, Rimel BJ, Li AJ, Cass I, Karlan BY, Walsh C. Ultrasound

guided transversus abdominis plane (TAP) block utilization

in multimodal pain management aer open gynecologic surgery.

Gynecol Oncol Rep. 2018;26:75-77.

8. Brady RR, Ventham NT, Roberts DM, Graham C, Daniel T.

Open transversus abdominis plane block and analgesic requirements

in patients following right hemicolectomy. Ann R Coll Surg

Engl. 2012;94(5):327-30.

9. Srivastava U, Verma S, Singh TK, Gupta A, Saxsena A, Jagar KD,

et al. Ecacy of trans abdominis plane block for post cesarean

delivery analgesia: A double-blind, randomized trial. Saudi J

Anaesth. 2015;9(3):298-302.

10. Carney J, McDonnell JG, Ochana A, Bhinder R, Laey JG. e

transversus abdominis plane block provides eective postoperative

analgesia in patients undergoing total abdominal hysterectomy.

Anesth Analg. 2008;107(6):2056-60.

11. Azawi NH, Mosholt KS, Fode M. Unilateral ultrasound-guided

transversus abdominis plane block aer nephrectomy; postoperative

pain and use of opioids. Nephrourol Mon. 2016;8(2):e35356.

12. Singh PM, Borle A, Makkar JK, Trisha A, Sinha A. Evaluation of

transversus abdominis plane block for renal transplant recipients -

A meta-analysis and trial sequential analysis of published studies.

Saudi J Anaesth. 2018;12(2):261-71.

13. Sanansilp V. Pain Control System in Siriraj Hospital Postanesthesia

Care Unit (PACU). Siriraj Med J. 2014;66(4):82-90.

14. Basta M, Sloan P. Epidural hematoma following epidural

catheter placement in a patient with chronic renal failure.Can

J Anaesth.1999;46:271-4.

15. Sun N, Wang S, Ma P, Liu S, Shao A, Xiong L.Postoperative

Analgesia by a Transversus Abdominis Plane Block Using

Dierent Concentrations of Ropivacaine for Abdominal Surgery:

A Meta-Analysis. Clin J Pain. 2017;33(9):853-63.

16. Collins JB, Song J, Mahabir RC. Onset and duration of intradermal

mixtures of bupivacaine and lidocaine with epinephrine. Can

J Plast Surg. 2013;21(1):51-53.

17. Yang P, Luo Y, Lin L, Zhang H, Liu Y, Li Y. e ecacy of

transversus abdominis plane block with or without dexmedetomidine

for postoperative analgesia in renal transplantation. A randomized

controlled trial. Int J Surg. 2020;79:196-201.

18. Choi S, Rodseth R, McCartney CJ. Eects of dexamethasone as a

local anaesthetic adjuvant for brachial plexus block: a systematic

review and meta-analysis of randomized trials. Br J Anaesth.

2014;112(3):427-39.

19. Farooq M, Carey M. A case of liver trauma with a blunt regional

anesthesia needle while performing transversus abdominis

plane block.Reg Anesth Pain Med.2008;33(3):274-5.

20. Lancaster P, Chadwick M. Liver trauma secondary to ultrasound-

guided transversus abdominis plane block.Br J Anaesth.2010;

104(4):509-10.

21. Narasimhulu DM, Scharfman L, Minko H, George B, Homel

P, Tyagaraj K. A randomized trial comparing surgeon-

administered intraoperative transversus abdominis plane

block with anesthesiologist-administered transcutaneous block.

Int J Obstet Anesth. 2018;35:26-32.

22. Dahl JB, Møiniche S. Pre-emptive analgesia. Br Med Bull.

2004;71:13-27.

23. Kolacz M, Mieszkowski M, Janiak M, Zagorski K, Byszewska

B, Weryk-Dysko M, et al. Transversus abdominis plane block

versus quadratus lumborum block type 2 for analgesia in renal

transplantation: A randomised trial. Eur J Anaesthesiol. 2020;

37(9):773-89.

Boonyapalanant et al.