Essentials of Our Current Understanding: Abdominal Wall Blocks · 2017. 4. 10. · Posterior...

REGIONAL ANESTHESIA AND ACUTE PAIN

SPECIAL ARTICLE

Essentials of Our Current Understanding:Abdominal Wall Blocks

Ki Jinn Chin, FRCPC,* John G. McDonnell, MD, FCARCSI,† Brendan Carvalho, MD,‡ Aidan Sharkey, FCAI,†Amit Pawa, FRCA,§ and Jeffrey Gadsden, MD, FRCPC, FANZCA||

Abstract: Abdominal wall blocks rely on the spread of local anestheticwithin musculofascial planes to anesthetize multiple small nerves or plex-uses, rather than targeting specific nerve structures. Ultrasonography is pri-marily responsible for the widespread adoption of techniques includingtransversus abdominis plane and rectus sheath blocks, as well as the intro-duction of novel techniques such as quadratus lumborum and transversalisfascia blocks. These blocks are technically straightforward and relativelysafe and reduce pain and opioid requirements in many clinical settings.The data supporting these outcomes, however, can be inconsistent becauseof heterogeneity of study design. The extent of sensory blockade is alsosomewhat variable, because it depends on the achieved spread of local an-esthetic and the anatomical course of the nerves being targeted. The blocksmainly provide somatic analgesia and are best used as part of a multimodalanalgesic regimen. This review summarizes the anatomical, sonographic,and technical aspects of the abdominal wall blocks in current use, examin-ing the current evidence for the efficacy and safety of each.

(Reg Anesth Pain Med 2017;42: 133–183)

Regional anesthesia of the trunk and abdominal wall has tradi-tionally centered on epidural analgesia, but enthusiasm forthis has waned with the increasing use of minimally invasive lap-aroscopic techniques, aggressive postoperative anticoagulationregimens, and emphasis on early ambulation. The popularity ofabdominal wall blocks, on the other hand, has dramatically in-creased in the last decade, thanks to the introduction of simpleyet effective techniques such as the transversus abdominis plane(TAP) block and the widespread availability of ultrasound (US)imaging. There has been an accompanying explosion in the scien-tific literature on abdominal wall blocks, and the purpose of thisreview is to summarize the current state of knowledge, with theaim of providing a guide to clinical application of these tech-niques, as well as future avenues of research. Toward these ends,the review describes the applied anatomy of the abdominal wall,as well as the sonoanatomy and basic technical considerationsof the blocks in current use. These include the TAP block,ilioinguinal-iliohypogastric (II-IH) block, rectus sheath block,and the newer techniques of transversalis fascia plane (TFP) blockand quadratus lumborum (QL) block. The evidence for clinical

From the *Department of Anesthesia, Toronto Western Hospital, University ofToronto, Toronto, Ontario, Canada; †Department of Anaesthesia, Clinical Sci-ences Institute, National University of Ireland, Galway, Ireland; ‡Departmentof Anesthesiology, Perioperative and Pain Medicine, Stanford UniversitySchool of Medicine, Stanford, CA; §Department of Anaesthesia, Guy's andSt Thomas' Hospitals, London, United Kingdom; and ||Department of Anesthe-siology, Duke University Medical Center, Durham, NC.Accepted for publication October 12, 2016.Address correspondence to: Ki Jinn Chin, FRCPC, Department of Anesthesia,

TorontoWestern Hospital, University of Toronto, McL 2-405, 399 BathurstSt, Toronto, Ontario, Canada M5T 2S8 (e‐mail: [email protected]).

The authors declare no conflict of interest.Copyright © 2017 by American Society of Regional Anesthesia and Pain

MedicineISSN: 1098-7339DOI: 10.1097/AAP.0000000000000545

Regional Anesthesia and Pain Medicine • Volume 42, Number 2, March

Copyright © 2017 American Society of Regional Anesthesia and Pain

outcomes of efficacy and safety associated with the various blocktechniques is discussed, including the specific application of ab-dominal wall blocks in the obstetric population.

ANATOMY OF THE ABDOMINAL WALLThe abdominal wall is a continuous cylindrical myofascial

structure that attaches to the thoracic cage superiorly, the pelvicgirdle inferiorly, and the spinal column posteriorly. The anatomi-cal relationship between the muscles and fascial layers of the ab-dominal wall is complex, and it is useful from both a conceptualand practical standpoint to consider the anterolateral and posteriorsections of the abdominal wall separately.

Anterolateral Abdominal WallThe anterolateral abdominal wall extends between the poste-

rior axillary lines on either side (Fig. 1). The superior boundariesare the costal margin of the 7th to 10th ribs and xiphoid processof the sternum, and the inferior boundaries are the iliac crests, in-guinal ligament, pubic crest, and symphysis. The layers of the ab-dominal wall are (from superficial to deep) skin and subcutaneoustissue, the abdominal muscles and associated aponeuroses,transversalis fascia, extraperitoneal fat, and parietal peritoneum.

The anterolateral abdominal wall has 3 flat muscles (externaloblique, internal oblique, transversus abdominis) arranged in con-centric layers and 1 paired vertical muscle in the midline (rectusabdominis). A small number of individuals have a second smallvertical midline muscle, the pyramidalis, which is of little clinicalsignificance. All 3 flat muscles taper off into aponeuroses as theyapproach the midline, and these aponeuroses form the tendinousrectus sheath that encases the rectus abdominis muscle (RAM).They blend in the midline with the aponeuroses of the other sideto form the linea alba. The specifics of how the muscles and theiraponeuroses relate to each other, as well as the various points ofreference on the abdominal wall (eg, midaxillary line, anterior ax-illary line, midclavicular line), will determine the layers visible onUS at different transducer locations.

The external oblique muscle (EOM) originates on the exter-nal aspect of the 5th to 12th ribs, and its fibers descend in aninferomedial direction to insert on the anterior iliac crest, lineaalba, and pubic tubercle (Fig. 1). Anteriorly, the EOM tapers offinto an extensive aponeurosis medial to the midclavicular lineand inferior to a line between the anterior superior iliac spine(ASIS) and the umbilicus; thus, in this area, only 2 muscle layers,internal oblique muscle (IOM) and transversus abdominis muscle(TAM), will be apparent onUS imaging (Fig. 2). The inferior edgeof the EOM aponeurosis forms the inguinal ligament; its medialedge blends with the aponeurosis of IOM to form the anteriorrectus sheath.

The IOM originates from the iliac crest inferiorly and thethoracolumbar fascia posteriorly, and its fibers ascend in asuperior-medial direction (perpendicular to those of the EOM)to insert on the inferior borders of the 10th to 12th ribs and thelinea alba. It is a fleshy muscle that on US imaging often appears

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FIGURE 1. Surface anatomy, muscular layers, and nerves of the anterolateral abdominal wall. The EOM and IOM and aponeuroses havebeen cut away on the right to show the TAP. The lateral cutaneous branches arise from their respective spinal nerves at or posterior to themidaxillary line and supply the skin of the lateral abdominal wall up to themidclavicular line. The T7-T9 nerves enter the TAP at ormedial to themidclavicular line. Communicating branches between the spinal nerves give rise to plexuses of nerves within the TAP and the rectus sheath.The rectus sheath is deficient midway between the umbilicus and pubis. AAL indicates anterior axillary line; MAL, midaxillary line; MCL,midclavicular line; PAL, posterior axillary line).

Chin et al Regional Anesthesia and Pain Medicine • Volume 42, Number 2, March-April 2017

as the thickest of the 3 flat muscle layers (Fig. 3). Medial to themidclavicular line, the IOM tapers off into its aponeurosis andcontributes to the formation of the rectus sheath.

The TAM originates on the internal aspect of the 7th to 12thcostal cartilages, the thoracolumbar fascia, and iliac crest. As itsname indicates, the fibers run transversely to insert on the lineaalba and pubic tubercle. Like the EOM and IOM, it tapers off me-dially into an aponeurosis that blends with the others to form therectus sheath (Fig. 1). The transition frommuscle into aponeurosisoccurs along a crescent-shaped line, and thus just inferior to thecostal margin, TAM runs deep to rectus abdominis for a short dis-tance before tapering off into its aponeurosis (Fig. 4).

The RAM is a paired muscle that originates on the pubiccrest and symphysis and ascends vertically to insert on the xiphoidprocess and fifth to seventh costal cartilages (Fig. 1). It is encasedwithin the rectus sheath and is attached to the anterior aspect ofthe rectus sheath by 3 or 4 transverse tendinous insertions. Theseinsertions divide the anterior rectus sheath compartment into sep-arate subcompartments, giving the RAM its “6-pack” appearancein thin muscular subjects and consequently impeding cranio-caudal spread of injectate. The posterior rectus sheath compart-ment, by comparison, is unsegmented and is thus a more logicalplace for local anesthetic injection.

The rectus sheath is formed by the blending of aponeurosesfrom the EOM, IOM, and TAM. In the superior three-quartersof the RAM, the anterior layer of the rectus sheath is formed bythe EOM and IOM aponeuroses. The IOM aponeurosis splits into

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2 layers and also contributes to the posterior layer of the rectussheath together with the TAM aponeurosis (Fig. 5A). However, in-ferior to the level of the ASIS (at the arcuate line), all 3 aponeuro-ses pass anterior to the RAM and form the anterior layer of therectus sheath. The inferior one-quarter of the RAM is thereforelined on its posterior aspect only by its epimysium and thetransversalis fascia (Figs. 1 and 5B).

Posterior Abdominal WallUnderstanding the structure of the posterior abdominal wall

is essential to the landmark-guided TAP block and the more novelUS-guided abdominal wall blocks, such as the TFP block andQL block.

Of the 3 muscle layers of the anterolateral abdominal wall,the TAM and IOM taper off posteriorly into their origins fromthe thoracolumbar fascia. The EOM, on the other hand, ends pos-teriorly in a free edge, which abuts against the latissimus dorsimuscle (Fig. 6).

The thoracolumbar fascia is a complex tubular structure ofblended aponeuroses and fascial layers that encases the deep mus-cles of the back and, as its name suggests, extends from the lumbarto thoracic spine.1,2 Tracing it laterally from its anchor point on thespinous processes and supraspinous ligament, the thoracolumbarfascia splits into 3 layers: the posterior and middle layers enclosethe paraspinal (erector spinae) muscles, and the middle and ante-rior layers enclose the QLmuscle (QLM), which is a quadrilateral

© 2017 American Society of Regional Anesthesia and Pain Medicine


FIGURE 2. Anatomy of the US-guided II-N and IH-N block. The IH-N and II-N emerge from the lateral border of psoas major and run over theanterior surface of QL, then the deep aspect of TAMand its aponeurosis. Both nerves pierce TAM to enter TAP at a variable location posteriorto the ASIS. The US probe may be placed in 1 of 2 locations (blue lines). (1) The recommended approach is to place the probe parallel andsuperior/posterior to the line connecting the umbilicus and the ASIS. The edge of the probe rests against the iliac crest (IC), which is visible asan acoustic shadow. In this position, the 3muscular layers of the abdominal wall are visible. The II-N and IH-N are located in the TAP betweenIOM and TAM and lie very close to the iliac crest. The AB-DCIA lies more medially in the TAP, as does the subcostal nerve (T12). Injection oflocal anesthetic is performed in the TAP close to the IC (circle), avoiding the nerves if they are visible. (2) If the probe is placed inferior to the lineconnecting the umbilicus and the ASIS, only the IOM and TAM are visible as muscle layers. The EOM has tapered off into its aponeurosis(EOA). The ilioinguinal and iliohypogastric nerves in this area are ascending through IOM into more superficial and subcutaneous planes andare not easily visualized or consistent in their location. AB-DCIA indicates ascending branch of deep circumflex iliac artery; IC, iliac crest; IH-N,iliohypogastric nerve; II-N, ilioinguinal nerve.

Regional Anesthesia and Pain Medicine • Volume 42, Number 2, March-April 2017 RA of the Abdominal Wall

muscle extending between the 12th rib and the (internal lip of the)iliac crest (Figs. 2 and 6). Medial and anterior to the QLM lies thepsoas major muscle. The posterior and middle layers of thora-columbar fascia fuse again lateral to the paraspinal muscles andmerge with the aponeuroses of the IOM and TAM.1,2

The transversalis fascia is a thin areolar tissue that lines thedeep surface of TAM and separates it from the parietal perito-neum. It is 1 part of the larger endoabdominal fascia that linesthe entire internal aspect of the abdominal wall. As such, it is con-tinuous inferiorly with the fascia iliaca3 and medially with theinvesting fascia of QLM and psoas major muscle (Fig. 6). In fact,the terms “anterior layer of thoracolumbar fascia” and “transversalisfascia” may be used interchangeably when referring to the fasciallayer investing the anterior surface of QLM.1 The transversalisfascia follows the QLM and psoas major superiorly through thediaphragm, passing under the lateral and medial arcuate ligamentsand blending with the endothoracic fascia of the thorax.4,5 Theserelationships of the thoracolumbar fascia, transversalis fascia andassociated muscles have important implications for the potentialspread of local anesthetic injected in the posterior abdominal wall.

The triangle of Petit (or inferior lumbar triangle) is the pri-mary surface anatomical landmark for the TAP block. It is bor-dered inferiorly at its base by the iliac crest, laterally by themedial free edge of EOM and medially by the lateral edge oflatissimus dorsi (Fig. 7). The triangle is covered superficially byskin and subcutaneous tissues, whereas its anterior (deep) flooris formed by IOM and the thoracolumbar fascia, which separates



it from the fat-filled retroperitoneal space. However, cadavericstudies indicate that there is significant anatomic variability inthe triangle of Petit.7,8 It was quite small in the majority of subjects(3.6 cm2 on average7) and even absent in 18% of subjects becauseof overlapping of the free edges of EOM and latissimus dorsi.8

This inconsistency limits its usefulness as a reliable surfaceanatomical landmark.

Innervation of the Anterior Abdominal WallThe anterior abdominal wall is innervated by the thora-

coabdominal nerves and the ilioinguinal and iliohypogastricnerves (Fig. 1). The thoracoabdominal nerves originate from theanterior rami of the lower 7 thoracic spinal nerves (T6-T12) andare the continuation of the respective intercostal nerves. The T12nerve is often also referred to as the subcostal nerve. They eachgive off a lateral cutaneous branch in the midaxillary line, whichascends to enter the subcutaneous tissues along the anterior axil-lary line and supplies the lateral abdominal wall. The anteriorbranches of the thoracoabdominal nerves subsequently emergefrom the costal margin and travel in the neurovascular TAP be-tween IOM and TAM. Note that the upper segmental nerves T6-T9 only enter the TAP medial to the anterior axillary line (T6 en-ters it just lateral to the linea alba) and that the other nerves enterit progressively more laterally (Fig. 1).9 This has implications forthe pattern of nerve involvement that can be expected by injectionat different locations in the TAP. Within the TAP, the lower seg-mental nerves (T9-L1) give off multiple communicating branches

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FIGURE 3. Anatomy of the anterolateral abdominal wall and the US-guided (USG) subcostal and lateral TAP blocks. The USG subcostalTAP block targets the T6 to T10 nerves, where they emerge into the TAP from under the costal margin. The probe is placed parallel andadjacent to the costal margin (blue line). Closer to the midline, the TAP is the plane between RAM and TAM. The EOM and IOM exist asaponeuroses in this region, which contribute to the formation of the anterior rectus sheath. The EOM and IOM become visible as the probeis moved more laterally along the costal margin. Injection may be performed at multiple points along the costal margin (circles) or a needleinserted in-plane in a continuous track along the costal margin (the oblique subcostal TAP block approach). Note that the lateral cutaneousbranches of the thoracoabdominal nerves are not covered by the block. The USG lateral TAP block targets the T10 to T12-L1 nerves. The probeis placed in a transverse orientation between the costal margin and iliac crest and in the midaxillary line. Injection is performed in the TAPbetween IOM and TAM (circle), with the needle usually inserted in an anterior-to-posterior direction. The TAM has a characteristic darkerhypoechoic appearance and is usually significantly thinner than the IOM.


to form a longitudinal TAP plexus, from which the terminal ante-rior branches arise.9

The terminal anterior cutaneous branches of the thoraco-abdominal nerves enter the rectus sheath at its lateral margin(the linea semilunaris). In the vast majority of cases (89%), thenerves run deep to the posterior surface of RAM before ascendingto pierce it 1.6 to 2.6 cm from its lateral edge.10 However, thesenerves occasionally directly pierce the lateral edge of the RAMand thus may be missed by a rectus sheath block. Once again,the nerves branch and communicate to form a longitudinal rectussheath plexus, before entering the subcutaneous tissue of the ante-rior abdominal wall.9

The existence of TAP and rectus sheath plexuses indicatesthat individual terminal nerves have multiple segmental originsand that the traditional depiction of the cutaneous innervation ofthe abdominal wall in terms of well-demarcated dermatomes isnot wholly accurate.11 This may be an explanation for the discrep-ancies between radiographically visualized spread of injectate inthe TAP, apparent extent of clinical analgesia, and the cutaneoussensory block observed in studies.6,12,13

The ilioinguinal and iliohypogastric nerves are classically de-scribed as terminal branches of the anterior ramus of the L1 spinalnervewith occasional contribution fromT12. Although this is truein the majority of individuals, there is significant variability, withup to 20% having origins from the L2 and L3 nerve roots.14–16

Both nerves emerge at the lateral border of psoas major and runinferolaterally on the ventral surface of QLM and TAM, just

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superior and parallel to the iliac crest (Fig. 2). The exact locationat which the nerves pierce TAM and enter the TAP is variable,but this is usually in the region of the anterior third of the iliac crestrather than more posteriorly.14,17,18 The iliohypogastric nerve en-ters the TAP earlier in its course than the ilioinguinal nerve, andin a significant number of individuals, the ilioinguinal nerve onlyenters the TAP very close to the ASIS (medial to the anterior ax-illary line).9 Both nerves continue to ascend through the IOMand EOM to supply the abdominal wall in the inguinal and pubicregions. They pierce the IOM at a variable distance medial to theASIS (approximately 3 ± 2 cm medial to ASIS and 1 cm superiorto inguinal ligament in adults.14 The anatomic variability in theircourse contributes to the high failure rates for blockade of thesenerves with the TAP block19,20 and the landmark-guided tech-niques of II-IH block.21,22

Vasculature of the Anterior Abdominal WallThere is a rich network of arteries and veins within the TAP,

which supplies the anterior abdominal wall and promotes the ab-sorption of local anesthetic injected in this plane. The main arter-ies are continuations of the lower thoracic intercostal arteries andthe deep circumflex iliac arteries. Within the rectus sheath, bilat-eral superior epigastric arteries (continuations of the internalthoracic arteries) anastomose with the deep inferior epigastricarteries (which arise from the external iliac arteries) and are atrisk of accidental puncture during rectus sheath block.



FIGURE 4. Anatomy of the anterolateral abdominal wall and the US-guided (USG) rectus sheath block. This block targets the terminalmuscular branches and anterior cutaneous branches of the thoracoabdominal nerves. The probe is placed in a transverse orientationsuperior to the umbilicus to visualize the lateral aspect of the RAM and rectus sheath. Close to the costal margin, the TAM is often visible lyingdeep to RAM. If the probe is placed inferior to the midpoint between umbilicus and pubic symphysis, the posterior rectus sheath is absent,and the deep surface of RAM is bounded by its epimysium and transversalis fascia. Injection is performed in the posterior rectus sheathcompartment between the lateral aspect of RAM and its deep investing layer of fascia (circles), to target the nerves before they ascendthrough RAM into their subcutaneous location.


TAP BLOCKThe landmark-guided TAP blockwas first described in 200123

and has since undergone multiple modifications. The “TAP block”is therefore a nonspecific term encompassing a heterogeneous groupof approaches that share the common end point of local anestheticinjection into the neurovascular fascial plane superficial to theTAM. The aim in all cases is to block some or all of the lower 6 tho-racic spinal nerves (T7-T12) and the iliohypogastric and ilioinguinalnerves (L1). The approaches differ primarily in the site of needle in-sertion and injection, which, because of the complex course of thelower thoracoabdominal nerves and interplay between muscularand aponeurotic layers of the abdominal wall at different locations,leads in turn to differences in the spread of local anesthetic and extentof analgesia. There has been a lack of consistency in the terminologyused to describe the different US-guided approaches24–26 and this re-view uses the nomenclature outlined in Table 1.

Landmark-Guided TAP Block

TechniqueThe landmark-guidedTAPblockwas first described byRafi23,44

and later byMcDonnell et al.6 Both authors describe the chief sur-face landmark as the insertion of the latissimus dorsi on the iliaccrest. The site of needle insertion is immediately anterior to this“latissimoiliac point (LIP)”44 and just superior to the iliac crest,in the triangle of Petit (Fig. 7). Given the variability in the sizeand presence of the triangle of Petit,7,8 the LIP may be a more ac-curate and consistent landmark.

McDonnell et al6 recommend seeking a “double-pop” as theend point for needle insertion, the first pop representing penetrationof the EOM fascia and the second pop the deep fascia of IOM.



Rafi,44 on the other hand, recommends contacting the externallip of the iliac crest and “walking” the needle tip over it until a sin-gle pop (penetration of the deep fascia of IOM) is obtained. Re-gardless, the subjective nature of tactile pops as end points forneedle insertion may contribute to failure of the technique, partic-ularly in inexperienced hands.45

Pattern of injectate spread and sensory blockRadiological studies indicate that 20 to 40 mL of local anes-

thetic injected using the landmark-guided TAP approach willspread within the TAP from the iliac crest superiorly to the costalmargin, anteriorly to the midaxillary line, and posteriorly to thelateral border of QLM.6,46 This TAP spread was thought to be re-sponsible for block efficacy (hence the name) and has been theprinciple upon which subsequent modifications have been based.However, posterior extension of injectate spread into the planebetween transversalis fascia and the ventral surface of QLM,and thence upward into the thoracic paravertebral space, hasalso been reported.46 It is postulated that this may be the moreimportant mechanism for producing analgesia, particularly abovethe T10 level, because the T7-T9 nerves only enter the TAPmedial tothe anterior axillary line and close to the costal margin. This patternof posterior and cranial spread is not seen with any of the US-guidedTAP approaches, and they may therefore have little in common withthe landmark-guided TAP block apart from the name.

The extent of cutaneous sensory block that can be achieved isless clear. McDonnell et al6 reported achieving a sensory block ofthe anterior abdominal wall from T7 to L1 in 6 volunteers (12blocks), but the precise sites of sensory testing were not described.Carney et al46 mapped the extent of sensory loss in 8 blocks andfound this was variable; in particular, blockade of the anterior

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FIGURE5. A, Sonoanatomy of the RAM and sheath in the supraumbilical region, with a corresponding schematic diagram showing the fascialand aponeurotic layers. The TAM is visible deep to the lateral edge of the RAM. Both the internal oblique aponeurosis and the transversusabdominis aponeurosis contribute to the posterior rectus sheath. The transversalis fascia and peritoneum lie deep to the posterior rectus sheathbut cannot always be clearly distinguished as separate layers. B, Sonoanatomy of the RAM and sheath in the infraumbilical region below thearcuate line, with a corresponding schematic diagram showing the fascial and aponeurotic layers. Here, there is no posterior rectus sheath.The layer immediately deep to the perimysium of RAM is transversalis fascia. The aponeuroses of all 3 muscle layers contribute only to theanterior rectus sheath. EOA indicates external oblique aponeurosis; IOA, internal oblique aponeurosis; P, peritoneum; SC, subcutaneous tissue;TAA, transversus abdominis aponeurosis; TF, transversalis fascia.


138 © 2017 American Society of Regional Anesthesia and Pain Medicine

Copyright © 2017 American Society of Regional Anesthesia and Pain Medicine. Unauthorized reproduction of this article is prohibited.

FIGURE 6. Anatomy of the posterior abdominal wall and the US-guided QL block. The EOM ends in a free edge abutting the latissimusdorsi. The IOM and TAM end in aponeuroses that blend with the thoracolumbar fascia. The thoracolumbar fascia itself splits into 3 layers(posterior, middle, and anterior) that envelop the QLM and ESM. The QL block is performed by placing a curvilinear probe on theposterolateral aspect of the abdominal wall in a transverse oblique orientation, between the iliac crest and costal margin (blue line).Key landmarks for identifying the QLM are the VB, TP, and PMM. At the L3-L4 level, the large intestine in the peritoneal cavity may be seendeep to the abdominal wall muscles (as it is here); at the L2-L3 level, the kidney is usually visible in the retroperitoneal space. The circlesindicate points for local anesthetic injection either anterior or posterior to QLM. ESM indicates erector spinae muscle; PMM, psoas majormuscle; TP, transverse process; VB, vertebral body.

FIGURE 7. Line drawing of the surface anatomy of the abdominal wall, including the lumbar triangle of Petit (arrows). As can be seen fromthe diagram, the triangle is bounded posteriorly by the latissimus dorsi muscle and anteriorly by the external oblique with the iliac crestforming the base of the triangle. The floor of the triangle is formed by the IOM. Reproduced with permission from McDonnell et al.6


© 2017 American Society of Regional Anesthesia and Pain Medicine 139


TABLE

1.Ultrasou

nd-G

uide

dAb

dominalWallB

locks

Block

Techn

ique

Clin

ical

Indication

Com

ments

SubcostalT

APblock2

7,28

Probepositio

n:placed

lateraltoxiphoidprocess;

paralleltocostalmargin.Injectionsite:(1)

Medialtolin

easemilu

naris:deep

toRAM

and

superficialtoTA

Mwhere

TAM

tapersoff

medially

into

itsfascialcontributionto

the

posteriorrectus

sheath.(2)

Lateralto

linea

semilu

naris:deep

toIO

Mandsuperficial

toTA

M.L

Adosing:0

.2–0.3mL/kgperblock,

concentrationadjusted

tokeep

with

inmax

recommendeddose

range(inmg).

Somaticanalgesiaforincisionsin

upper

(T6-T7to

T9-T10)anterior

abdominalwall.

Will

notcover

incisionslateraltoanterior

axillarylin

e.

Oblique

subcostalT

APblock2

9,30

Probepositio

n:Midclavicular

lineto

anterior

axillarylin

e;paralleltocostalmargin.

Injectionsite:E

xtensive

injectiontrackin

TAP,

deep

toIO

MandsuperficialtoTA

M,along

theentirecostalmargin.LAdosing:

0.2–0.3mL/kgperblock,concentration

adjusted

tokeep

with

inmax

recommended

dose

range(inmg).


upper

(T6-T7to

T9-T10)anterior

abdominalwall.

Technically

challengingneedleinsertion.

Will

notcover


axillarylin

e.

Lateral(m

idaxillary)

TAPblock3

1,32

Probepositio

n:Midaxillarylin

e;paralleland

superior

toiliac

crest.Injectionsite:D

eepto

IOM

andsuperficialtoTA

M,inmidaxillarylin

e.LAdosing:0



tokeep

with

inmax

recommendeddose

range(inmg).


lower

(T10

toT12-L1)

anterior

abdominalwall.

Will

notcover


axillarylin

e.L1isnotconsistently

covered.

Bilaterald

ual-TA

Pblock1

2,28,33

Com

binatio

nof

bilateralsubcostalandlateral

TAPblocks.L

Adosing:0

.15–0.2mL/kgper

block,concentrationadjusted

tokeep

with

inmax

recommendeddose

range(inmg).

Somaticanalgesiaforextensive(T7-T12)

incisionsin

anterior

abdominalwall.

Will

notcover


axillarylin

e.

II-IHnerveblock3

4,35

Probepositio

n:Posteriorandsuperior

toASIS,

paralleltothelin

ebetweenASISandum

bilicus.

Injectionsite:M

edialtoacousticshadow

ofASISwith

intheTA

P.LAdosing:0

.1–0.15mL/kg,


tokeep

with

inmax

recommendeddose

range(inmg).


theright

orleftiliac

fossaof

theabdomen.

Visualizationof

nerves

isnotalwayspossible

ornecessary.

Rectussheath

block3

6,37

Probepositio

n:Transverseorientationlateralto

linea

alba

andjustsuperior

toum

bilicus.

Injectionsite:M

edialtoacousticshadow

ofASISwith

intheTA

P.LAdosing:0

.1–0.2

mL/kg

perside,concentratio

nadjusted

tokeep

with

inmax

recommendeddose

range(inmg).

Somaticanalgesiaformidlin

eincisionsin

anterior

abdominalwall.

Bilateralinjectio

nsrequired.D

ivided

injections

superior

andinferior

toum

bilicus

may

provide

forbetterspread.

AnteriorQLblock3

8–41

Probepositio

n:Posterioraxillarylin

e,parallel

toiliac

crest.Injectionsite:A

nterior(deep)

toQLM.L

Adosing:0



tokeep

with

inmax

recommendeddose

range(inmg).

Analgesiaformidlower

(T8-T12)incisionsin

anterior

abdominalwall.

Needlemay

beinserted

inlateral-to-m

edial

direction3

8,39or

posterior-to-anterior

(transmuscularapproach

40,41 ).L

umbarplexus

blockmay

occurwith

theposterior-to-anterior

(transmuscular)approach.




PosteriorQLblock3

8Probepositio


e,parallel

toiliac

crest.Injectionsite:P

osterior

(superficial)

toQLM.L

Adosing:0



tokeep

with

inmax

recommendeddose

range(inmg).

Analgesiaformidlower

(T8-T12)incisionsin

anterior

abdominalwall.

Lum

barplexus

blockmay

occur.

TFP

block4

2,43

Probepositio


e,parallel

toandagainstiliaccrest,andangled

slightly

inferiorly.Injectio

nsite:D

eepto

taperedtip

ofTA

Mandsuperficialtotransversalis

fascia.

LAdosing:0



tokeep

with

inmax

recommendeddose

range(inmg).

Analgesiaforincisionsover

theanterior

iliac

crest,theanterior

iliac

crestitself,andL1

derm

atom

eof

theanterior

abdominalwall.

Siteof

LAdepositio

nismoreinferior

and

anterior/lateraltothatof

theQLblock.

Lum

barplexus

blockmay

occur.

LAindicateslocalanesthetic;U

SG,U

S-guided.




abdominal wall was patchy and incomplete. Areas that were consis-tently blocked were the area of injection, groin, and upper lateral thigh.

US-Guided Lateral TAP Block

TechniqueThe US-guided lateral TAP block was first described in

2007.31,47 Ultrasound allows direct visualization of the abdominalwall layers, needle placement, and local anesthetic spread in theTAP, and this was critical in popularizing the TAP block. Descrip-tions of the technique vary slightly in the published literature, butin general, the US transducer is placed in a transverse orientationmidway between the costal margin and iliac crest and centered onthe midaxillary line (Fig. 3).32 The needle is inserted in the ante-rior axillary line in-plane to the transducer and enters the TAP inthe midaxillary line (Figs. 3 and 8). Although initially touted asa US-guided version of the landmark-guided TAP block, it is nowclear that the US-guided lateral TAP is quite different with regardtowhere local anesthetic is injected. The point of needle entry intothe TAP is anterior and superior to the LIP and triangle of Petit,which results in a different pattern of injectate spread.

Pattern of injectate spread and sensory blockRadiological studies indicate that the US-guided lateral TAP

produces injectate spread confined to an area centered around themidaxillary line and that extends only as far as the costal margin,the iliac crest, and the anterior axillary line in most cases.46,48 Pos-terior spread beyond the midaxillary line is limited compared withthe landmark-guided TAP block.33,46 Thoracoabdominal nervesthat are consistently involved include T10, T11, T12, and, to alesser extent, L1.19,48 T9 and above are usually not involved, asthey enter only the TAP medial to the anterior axillary line.

The evidence for the extent of cutaneous sensory block isconflicting andmay depend on whether assessment involves com-prehensive area mapping or merely “point” testing using tradi-tional dermatomal maps and surface landmarks. Studies usingthe latter approach indicate that craniocaudal coverage is variable,but the results are fairly consistent with the cadaveric dye studies.In general, the US-guided lateral TAP consistently provides block-ade of the T11-T12 dermatomes and, in the majority of cases,also the T10 dermatome.12,19,49 The T9 and L1 dermatomes areblocked less than 50% of the time.19 Laterally, the block doesnot usually extend beyond the midclavicular or anterior axillaryline,12,19 and this is attributed to failure to anesthetize the lateralcutaneous branches of the segmental nerves, which arise and leavethe TAP posterior to the midaxillary line. Increasing the volumeof injectate (eg, from 15 mL to 30 mL in an adult patient) doesnot appear to significantly increase the extent of spread.12,46

On the other hand, in studies where the area of cutaneoussensory loss is systematically mapped out, this appears to behighly variable and to follow a nondermatomal distribution thatdoes not extensively involve the anterior abdominal wall.13,46

Støving et al13 observed a greater proportion of sensory loss(76% vs 24%) lateral to the line passing through the ASISrather than medial to it, suggesting that the lateral cutaneousbranches may be anesthetized after all. As in previous studies,the craniocaudal extent of sensory loss was confined to theinfraumbilical area. There was evidence of significant blockadeof the abdominal musculature, which may partly explain the dis-crepancy between the limited pattern of cutaneous sensory lossobserved in this study and clinical reports of good analgesic effi-cacy. The nondermatomal pattern may be due to the aforemen-tioned existence of a TAP plexus and overlapping contributionof multiple spinal nerves to individual terminal branches.9

141


FIGURE 8. Ultrasound-guided lateral TAP block. A, Preinjection image. The US probe is placed in a transverse orientation between thecostal margin and iliac crest in the midaxillary line. A needle is advanced in an anterior-to-posterior direction through the muscular layers ofthe abdominal wall to reach the TAP between IOM and TAM. The TAM has a characteristic darker hypoechoic appearance and is usuallysignificantly thinner than the IOM. B, Postinjection image. Local anesthetic (LA) has distended the TAP, separating IOM and TAM. SCindicates subcutaneous tissue. Reproduced with permission from KJ Chin Medicine Professional Corporation.


US-Guided Subcostal TAP Block

TechniqueThe US-guided subcostal TAP block was described in 2008

as a means of reliably providing analgesia of the supraumbilicalabdominal wall (T6-T9) and is based on the fact that these nervesenter the TAP at the costal margin and medial to the anterior axil-lary line (Fig. 3). The original description involved insertion of a100- to 150-mm needle into the TAP close to the xiphoid process,advancing it in an inferolateral direction and injecting local anes-thetic parallel to the costal margin and as far as the anterior iliaccrest.29 Alternatively, the needle may be inserted in the anterioraxillary line and in a superomedial direction toward the xiphoidprocess; this allows preoperative placement of a catheter outsidethe surgical field.33,50 This approach, subsequently termed the“oblique subcostal TAP block,”30 requires a high degree of tech-nical skill. Subsequent modifications include performing mul-tiple separate injections along the costal margin27 or performing

142


a single “point” injection either medial to the linea semilunaris(between RAM and TAM)12 or lateral to it (between IOM andTAM)27,51 (Fig. 9).

Pattern of injectate spread and sensory blockCadaveric and volunteer studies support the potential to

block the upper segmental nerves (T6-T9) as they emerge intothe abdomen. However, the extent of sensory block seen withthe subcostal TAP block is variable and may depend on wherethe local anesthetic is deposited in relation towhere nerves emergefrom under the costal margin into the TAP. Injection lateral to thelinea semilunaris produces a block centered on T10-T11 and notextending higher than T9 most of the time.19,27 If T6-T8 coverageis desired, local anesthetic should be injected medial to the lineasemilunaris, between RAM and TAM, and as close to the xiphoidprocess as possible.12,27 Even then, it appears difficult to achievespread to T6 and T7 more than 50% to 70% of the time.28,33



FIGURE 9. Sonoanatomy of the US-guided subcostal TAP block. The probe is placed parallel and adjacent to the costal margin. Closer to themidline (upper image A), the TAP is the plane between RAM and TAM. The EOM and IOM exist as aponeuroses in this region, whichcontribute to the formation of the anterior rectus sheath. The EOM and IOM become visible as the probe is moved more laterally along thecostal margin (lower image B). The asterisks indicate suitable injection points for a US-guided subcostal TAP block. SC indicatessubcutaneous tissue. Reproduced with permission from KJ Chin Medicine Professional Corporation.


Injection that extends to the lateral aspect of the costal marginand iliac crest can produce a block that extends inferiorly to T12and occasionally the L1 dermatome.19,27 The lateral cutaneousbranches are not blocked, and thus, incisional analgesia doesnot extend lateral to the anterior axillary line.33,52

US-Guided Bilateral Dual TAP Block

TechniqueA combination of the US-guided subcostal and lateral TAP

blocks, termed the US-guided bilateral dual -TAP block and in-volving a total of 4 injections, has been proposed as a method ofproviding analgesia to the entire anterior abdominal wall.12,28 Inthe original description, the subcostal block is performed by a“point” injection medial to the linea semilunaris, between RAMand TAM. Sondekoppam et al33 have recently proposed a modifi-cation that utilizes an extended needle track similar to the obliquesubcostal approach and is designed primarily to allow the preoper-ative insertion of catheters outside the surgical field. Needle inser-tion occurs in a lateral-to-medial direction, starting at the anterioraxillary line and traveling along the costal margin superiorly toreach the linea semilunaris. The needle is then withdrawn andinserted inferiorly toward the pubic symphysis and parallel tothe inguinal ligament to provide coverage of the lower abdomen.

Pattern of injectate spread and sensory blockIn their evaluations of the US-guided bilateral dual-TAP

block, Børglum et al12 have shown that the lateral TAP block pro-duces spread confined to the lower abdomen and a sensory blockof T10-T12, whereas the subcostal TAP block produced spread inthe upper abdominal TAP. By combining the two, they were ableto consistently obtain a cutaneous sensory block of T9-T12 with



extension to T7-T8 in the majority of subjects and occasionallyas high as T6.12,28

Sondekoppam et al33 evaluated their own modified tech-nique in a small cadaveric study and similarly found dye spreadinvolving T8 to L1 thoracoabdominal nerves in the majority of in-jections and spread to T7 in a small proportion. The lateral extentof dye spread was confined to an area between the anteriorand midaxillary line, leading the investigators to conclude thatthe lateral cutaneous branches are unlikely to be covered inthis approach.

Surgical TAP BlockSeveral surgical approaches to the TAP block have been de-

scribed. In laparoscopic surgery, the surgeon inserts a block nee-dle percutaneously, with entry into the TAP signaled by tactilepops and confirmed by visualization of inward bulging of theTAM as local anesthetic is injected.53 An alternative techniquehas been described in open abdominal surgery, where the woundedges are retracted and a needle inserted from the interior of theabdomen through the parietal peritoneum and into the TAP as sig-naled by a single tactile pop.54–56 Finally, a technique of surgicaldissection into the TAP, followed by direct injection or placementof a catheter, has been described in abdominoplasty57 and abdom-inal flap breast reconstruction surgery.58 Advantages cited for thesurgical approach include better matching of the site of injectionto site of surgery, ease and speed of performance, and accuracyof injection into the correct tissue plane. There are no studies ex-amining the spread of injectate with surgically placed TAP blocksor catheters, and most of the clinical data come from case seriesand retrospective case-control studies.57,59–61 Although the lattersuggest that surgical TAP blocks can reduce early postoperative

143



opioid requirements and improve pain scores, the limited random-ized controlled trial (RCT) data available at present, mostly in thesetting of laparoscopic abdominal54,56,62 and breast reconstructionsurgery,63 indicate only a modest analgesic benefit compared with pla-cebo. In particular, Lapmahapaisan et al56 failed to showanalgesic ben-efit in pediatric open abdominal surgery, which they attributed to thelimited ability of their TAP block to cover subcostal incisions.

Clinical Efficacy of the TAP BlockA recent meta-analysis of US-guided TAP block (encom-

passing all approaches and surgery types) concluded that itconfers a statistically significant but clinically modest analgesicbenefit (mean reductions of 6 and 11 mg of intravenously admin-istered [IV] morphine at 6 and 24 hours, respectively) in adult pa-tients undergoing abdominal laparotomy, laparoscopy, or cesareandelivery.64 A similar meta-analysis of pediatric TAP and rectussheath blocks also reported analgesic benefit but only in the earlypostoperative period (first 6-8 hours).65 The authors in both arti-cles rightly note that their findings should be viewed with cautionin view of the pronounced heterogeneity in the included studiesand their analysis. As presented previously, different TAP blockapproaches produce different patterns of local anesthetic spread,46

which may in turn influence analgesic efficacy. This caveat mustbe borne in mind when interpreting the overall evidence for clin-ical efficacy of the TAP block in various surgical settings and maybe partly responsible for some of the conflicting data. In particu-lar, the landmark-guided TAP block appears to have a differentmechanism of action from the US-guided TAP blocks. The poste-rior and cranial spread to the thoracic paravertebral space demon-strated with the landmark-guided TAP block may producesuperior analgesia and thus explain the preponderance of favor-able analgesic outcomes in studies that used this approach. Inthe following section, we present a qualitative review of the evi-dence for the different TAP block approaches according to typeof surgery, with data from the RCTs summarized in Table 2.

Upper Abdominal Surgery

Major open upper abdominal surgeryThe US-guided subcostal TAP is preferred to the US-guided

lateral TAP block in upper abdominal surgery because it is morelikely to cover the supraumbilical dermatomes. For extensivesurgery, both approaches may be combined as in the bilateraldual-TAP block. There are no published data on the efficacyof the landmark-guided TAP block specifically in upperabdominal surgery.

Four studies compared the postoperative analgesia providedby US-guided TAP blocks with thoracic epidural analgesia inmajor upper abdominal surgery.50,52,66,67 Two of these utilizedbilateral subcostal TAP catheters inserted at the end of surgery andan intermittent bolus regimen of local anesthetic52,66; one utilizeda preincisional single-shot subcostal TAP block67; and the fourthinserted preincisional bilateral dual-TAP catheters (4 in total,using the approach described by Sondekoppam et al33) with con-tinuous infusion of local anesthetic.50 On the whole, these studiesindicate that subcostal TAP block is a useful alternative in upperabdominal surgery where epidural analgesia is contraindicatedor undesirable and also has fewer adverse effects, particularly hy-potension.50,66,67 Nevertheless, thoracic epidural analgesia is stilllikely to provide superior analgesia compared with the subcostalTAP block, particularly if the incision extends lateral to the ante-rior axillary line,52 if there is a large component of visceral pain,or if TAP catheters are not utilized to extend analgesic duration.Furthermore, TAP catheter insertion can be technically complex,

144


time consuming, and associated with technical failure52 when insertedpostoperatively because of disruption of the normal tissue planes.

Laparoscopic cholecystectomyBoth US-guided subcostal and lateral TAP blocks have

been studied in laparoscopic cholecystectomy. The subcostalTAP provides superior analgesia compared with the lateral TAPblock,68,69 which is not surprising given that a standard laparo-scopic cholecystectomy utilizes subcostal port sites in additionto a periumbilical one.

Although early studies suggested that the lateral TAP blockmay be of benefit,70,71 they suffered from methodological limita-tions, including use of a surgical technique utilizing only infra-umbilical port sites, and lack of a multimodal analgesic regimen.Subsequent studies have shown marginal benefit of TAP blocksin reducing opioid consumption or pain scores.72–75 Overall,TAP blocks do not have a routine place in laparoscopic cholecys-tectomy, given the low pain scores that can be achieved withsystemic multimodal analgesia and local anesthetic infiltrationof port sites.72,75

Bariatric surgeryTwo RCTs have examined the analgesic efficacy of TAP

blocks in laparoscopic gastric (roux-en-Y) bypass surgery, withconflicting results.51,76 Although Sinha et al76 reported that a post-surgical US-guided TAP block reduced 24-hour opioid consump-tion and pain scores, no details on the TAP block technique andintraoperative or postoperative analgesic regimen were supplied,and it appears likely that multimodal analgesia was not adminis-tered. Albrecht et al,51 on the other hand, found that when addedto a regimen of intraoperative ketorolac, local anesthetic infiltra-tion of port sites, and postoperative acetaminophen a presurgicalUS-guided subcostal TAP block did not significantly reduce24-hour opioid consumption, time to first analgesic request, orpain scores up to 48 hours. At this time, therefore, TAP blocksdo not appear to be a useful addition to multimodal analgesia inthis population.

Lower Abdominal Surgery (Nonobstetric)

Major gynecological surgery including totalabdominal hysterectomy

Multiple studies have examined the role of bilateral TAPblocks in major open gynecological surgery, especially total ab-dominal hysterectomy. A 2013 meta-analysis of data from 4 pub-lished studies (one using the landmark-guided TAP block77 andthe others using the US-guided lateral TAP block78–80) reportedthat TAP blocks significantly reduced 24-hour opioid consump-tion and reduced rest and dynamic pain at 2 hours but not 24 hoursfollowing hysterectomy.110

More recent studies are less positive, however. Two studiesthat investigated the addition of bilateral US-guided lateral TAPblocks to a perioperative multimodal analgesia regimen of nonste-roidal anti-inflammatory drugs (NSAIDs) and acetaminophenfound no difference in 24-hour opioid consumption.81,82 Therewere minimal reductions in rest and dynamic pain, with thegreatest effect observed in the first 2 postoperative hours. Simi-larly, 2 studies83,84 comparingUS-guided lateral TAP block to pla-cebo in the setting of robotic surgery for gynecologic cancer foundno difference in 24-hour opioid consumption or pain scores. Twoadditional studies, on the other hand, both using the landmark-guided TAP approach, reported that bilateral TAP blocks werebeneficial in reducing postoperative opioid consumption and painscores compared with either placebo85 or wound infiltration.86



TABLE

2.Su

mmaryof

RCTs

onTA

PBloc

ks

Stud

yStan

dardized

Man

agem

ent

Intervention

Com

parator

Ana

lgesicOutcomes

Other

Outcomes/Com

ments

Major

upperab

dominal

surgery

Nirajetal,522011

N=62,openhepatobiliary

orrenalsurgery

(incision

superior

toT10).Intraop:

GA+T7-T9epidural

20mLof

0.25%

bupivacaine.Postop:P

Oacetam

inophen1gevery

6h,IV

tram

adol

5-100mg

every6hprn.

BilateralU

SGsubcostalT

AP

cathetersinserted

atend

ofsurgery.Interm

ittent

bolusesof

1mg/kg

0.375%

bupivacaine

every8hfor72

h.

Postop

patient-controlled

epiduralinfusion

of0.125%

bupivacaine

+fentanyl

2μg/m

Lat6-12

mL/h.

Similarpainscores

atrestand

oncoughing

upto72

hpostop.S

ignificantly(Sig)

moretram

adoluseinTA

Pvs

epiduralgroup(m

edian

400mgvs

200mg).8

patients

(30%

)intheTA

Pgrouphad

painfrom

lateralincisions

ordrainsites.

Therapeuticsuccessrateof

63%

inTA

Pgroupvs

78%

inepiduralgroup(N

S).

Technicalfailure

ofTA

Pcatheter

insertionin

7%.

45%

ofTA

Pcathetershad

tobe

resitedpostop

vs7%

ofepidurals.

Wahba

and

Kam

al,662014

N=44,upper

abdominal

surgery.Intraop:

GA+IV

fentanyl

infusion.P

ostop:

IVPC

Amorphine.No

system

icMMA.

BilateralU

SGsubcostal

TAPcathetersinserted

atendof

surgery.Loading

dose

of20

mLfollowed

by15

mLof

0.25%

bupivacaineevery8h

for48

h.

T9-T10

thoracicepidural,

inserted

preop.Postop:

loadingdose

of10

mL

of0.125%

bupivacaine

followed

byinfusion

at6-8mL/h.

Sighigher

pain

scores

atrest

andon

coughing

upto

48h

postop

intheTA

Pgroup.

Sigmorepatientsneeding

IVPC

Amorphinein

TAP

vsepiduralgroup(100%

vs73%).Sigshortertim

eto

firstm

orphinedose

inTA

Pvs

epiduralgroup(m

ean

210vs

311min).Sighigher

morphineuseon

POD1in

TAPvs

epiduralgroup

(median18

vs12

mg)

and

POD2(m

edian11

vs7mg).

Siglongertim

etoflatusinTA

Pvs

epiduralgroup(m

ean52

vs45

h).S

igshortertim

eto

ambulationinTA

Pvs

epidural

group(m

ean48

vs63

h)Sig

lowerincidenceof

hypotension

inTA

Pvs

epiduralgroup(9%

vs46%).Low

erpatient

satisfactioninTA

Pvs

epidural

group(m

edian1vs

3on

0-to

3-pointscale).

Wuetal,672013

N=82,openradical

gastrectom

y.Intraop:

GA+IV

remifentanil

infusion

+IV

sufentanil

bolusesevery1.5h.

Postop:IVPC

Amorphine.

Nosystem

icMMA.

Bilateralp

reincisional

USG

obliq

uesubcostal

TAPblocks

with

20mL

of0.375%

ropivacaine.

GAgroup:no

block,

system

icanalgesiaonly.

TEAgroup:T8-T9

thoracicepidural,

inserted

preop.Intraop:

Loading

dose

8mL

0.25%

ropivacaine,

followed

by5mL

0.25%

ropivacaine

every1h.Postop:

infusion

of0.125%

bupivacaine+morphine

8μg/mLat5mL/h.

TAPvs

GAgroups:S

iglower

dynamicpainscores

at0-6h

inTA

Pgroup,butsimilarrest

anddynamicpainscores

upto

72h.Siglessmorphineuseat

0-6h(m

edian5vs

8mg)

inTA

Pgroup,butsimilaratall

otherintervalsup

to72

h.TA

Pvs

TEAgroups:S

imilarrest

anddynamicpainscores

upto72

h.Similarmorphineuse

at0-6h(m

edian5vs

3mg)

butsighigherinTA

Pgroup

atallotherintervalsup

to72

h.

Technicalfailure

ofepidural

insertionin

2patients(7%)in

TEAgroup.Higherintraop

ephedrinerequirem

entand

incidenceof

postoperative

hypotensionin

theTEAvs

TAPor

GAgroup(21%

vs0%

vs0%

).

Contin

uednextpage




TABLE

2.(Con

tinued)

Stud

yStan

dardized

Man

agem

ent

Intervention

Com

parator

Ana

lgesicOutcomes

Other

Outcomes/Com

ments

Ganapathy

etal,502015

N=50,openlaparotomy.

Intraop:

GA+IV

fentanyl

orhydrom

orphoneboluses

prn.Postop:acetaminophen

650mgevery6h,

naproxen

500mgevery

12h,gabapentin

300mg

every12

h.

Bilateralp

reincisionalUSG

dual-TAPcatheters(4

intotal)usinglateral-to-m

edial

approach.L

oading

dose

20mLof

0.5%

ropivacaine

ateach

catheter

site,followed

byinfusion

of0.35%

ropivacaineat4–5mL/h

into

the2catheterson

each

side

usingaY-connectorand

elastomericpump.Postop:

IVPC

Ahydrom

orphone

T7-T8or

T8-T9thoracic

epiduralanalgesia(TEA),

inserted

preopandloaded

with

0.25%

bupivacaine

5mL+3mLprnto

achieveaT6-T12

sensory

block.Intraop:

infusion

of0.1%

bupivacaine+

hydrom

orphone10

μg/m

Lat8mL/h.P

ostop:

infusion

of0.1%

bupivacaine+

hydrom

orphone10

μg/m

Lat8mL/h

with

3mLPC

Abolusevery20

min

prn

for72

h.

Similarrestanddynamicpain

scores

inboth

groups

upto

72h.Similarmorphine

useat0-24

hin

TAPvs

TEA

group(m

ean14

vs16

mg)

and48-72h(13vs

10mg),

butsig

higher

inTA

Pgroup

at24-48h(13vs

5mg).

Fewer

patientswith

pain

scores

>5/10

inTA

Pgroup

(15%

vs29%,n.s.)

Noblockfailuresineithergroup.

Similarly

high

patient

satisfactionscores

inboth

groups.H

igherincidenceof

significanthypotension

inTEA

group(21%

vs0%

).Longer

blockperformance

timein

TAPgroup(m

ean36

min

vs15

min).

Lapmahapaisan

etal,562015

N=54,pediatricmajor

open

abdominalsurgery(upper

>lower).Intraop:

GA+IV

fentanyl

prn.Postop:IV

fentanyl

ormorphineprn.

NoMMA.

Group

I:bilateralsurgicalT

AP

blocks

with

0.5–1mL/kg

0.25%

bupivacaineatend

ofsurgery.

Group

II:W

ound

infiltration

with

0.5–1mL/kg0.25%

bupivacaineatend

ofsurgery.Group

III:

Noblocks.

Nosigdifference

between

groups

inincidenceof

inadequateanalgesiaor

proportio

nof

pain-free

patients.Nosigdifference

inopioid

useover

24hor

timeto

1stanalgesicuse

betweengroups.

Lap

aroscopiccholecystectom

yBhatia

etal,682014

N=60,laparoscopic

cholecystectom

yIntraop:

GA+IV

morphine0.1mg/kg.

Postop:IVacetam

inophen1g

every6h,IV

tram

adol

1–2mg/kg

prn.

Group

I:BilateralU

SGlateral

TAP.Group

II:B

ilateralU

SGsubcostalT

APBolus

injection

of15

mL0.375%

ropivacaine

oneach

side;allblocks

performed

atendof

surgery.

Group

III:Noblocks.

Siglower

restanddynamic

painscores

with

(a)

subcostalT

APvs

noblock

upto24

h;(b)lateralT

AP

vsno

blockup

to2h;(c)

subcostalT

APvs

lateral

TAPfrom

4-24

h.Low

er24

htram

adolusein

subcostalT

APvs

lateral

TAPvs

noblock(m

ean

27mgvs

89mgvs

125mg).

Longertim

etofirstrequest

foropioidinsubcostalT

AP

vslateralT

APvs

noblock

(mean552minvs

411min

vs150min).

Nosigdifference

innausea,

vomiting,orsedationbetween

groups.M

eandynamicpain

scores

(0–10)

inpatients

receivingno

blockranged

from

2.5to4.2during

1st24h.




Shin

etal,692014

N=45,laparoscopic

cholecystectom

yIntraop:

GA+IV

ketorolac30

mg

+IV

fentanyl

prnPostop:

IVfentanyl,IVketorolac

30mgprnin

PACU;

IVnalbuphine

10mgprn

inward.NoMMA.

Group

II:B

ilateralU

SGlateral

TAP.Group

III:BilateralU

SGobliq

uesubcostalT

APBolus

injectionof

20mL0.375%

ropivacaineperside;all

blocks

performed

preincision.

Group

1:no

blocks.

Siglower

restanddynamic

painscores

with

(a)subcostal

TAPvs

noblockup

to3h;

(b)lateralT

APvs

noblockup

to1h;(c)subcostalT

APvs

lateralT

APfrom

1–24

h.Nosigdifference

inanalgesic

usebetweengroups.

Oblique

subcostalT

APtended

toproducecutaneoussensory

blockfrom

T9-T10

vsT12-L1

with

lateralT

AP(but

not

consistentlyseen).Mean

dynamicpain

scores

(0-10)

inpatientsreceivingno

block

ranged

from

3.0to

4.7at

3–24

h.El-Daw

latly

etal,702009

N=42,laparoscopic

cholecystectom

yusing

4infraumbilicalports.

Intraop:

GA+sufentanil

0.1μg/kgprnPostop:IV

PCAmorphine.NoMMA.

Preincisionalb

ilateralU

SGlateralT

APblockwith

15mL0.5%

bupivacaine

perside.

Noblocks.

Sigless

intraopsufentanilin

TAPgroup(m

ean8.6μg

vs23.0μg).Sigless

morphine

usein

24hin

TAPgroup

(mean10.5mgvs

22.8

mg).

Pain

scores

notassessed.

Raetal,712010

N=54,laparoscopic

cholecystectom

y.Intraop:

GA(TIVA)+remifentanil

infusion.P

ostop:

IVfentanyl

20μg

prnor

IVketorolac

30mgprnin

PACU,and

IVketorolac30

mgevery

8hfor1st2

4h.

Preincisionalb

ilateralU

SGlateralT

APblocks

with

15mLof

LAperside.

Group

I:0.25%

bupivacaine.

Group

II:0

.5%

bupivacaine.

Control

group:

noblocks.

Siglower

pain

scores

inboth

TAPgroups

vscontrolg

roup

upto

24h.Similarpain

scores

betweenTA

Pgroups.F

ewer

patientsin

either

TAPgroup

received

ketorolacor

fentanyl

inPA

CUvs

control.

Fewer

patientsin

either

TAP

groupcomplainedof

sleep

disturbancedueto

pain.

Petersen

etal,722012

N=74,laparoscopic

cholecystectom

y.Intraop:

GA(TIVA)+remifentanil

infusion

+IV

sufentanil

0.2μg/kgatendof

surgery.

Postop:P

Oacetam

inophen

1gevery6h,PO

ibuprofen

400mgevery6h.IV

morphine2.5mgprnin

1st2

h;PO

ketobemidone

2.5mgprnin

2–24

h.

Preincisionalb

ilateralU

SGlateralT

APwith

20mL0.5%

ropivacaineperside.

Noblocks.

Sigreductionindynamicand

restpainover24

h(m

easured

asarea

undercurve).S

iglower

morphineuseinTA

Pvs

control

groups

at0-2h(m

edian5mg

vs7.5mg).N

osigdifference

inketobemidoneuseinTA

Pvs

controlg

roupsat2–24

h(m

edian0mgvs

5mg).

Similarincidenceof

nausea

and

vomiting,and

levelo

fsedation

betweengroups.G

raphicaldata

indicatethatdifferencesinpain

scorearemostm

arkedup

to8h,butsimilarat24

h.

Tolchard

etal,732012

N=43,laparoscopic

cholecystectom

y.Intraop:

GA+fentanyl

3μg/kg+

acetam

inophen15–20mg/kg

+diclofenac

0.5mg/kg.

Postop:IVfentanyl

20μg

prnin

PACU;IM

morphine,

POtram

adol,orPO

codeine

and“non-opioid”

analgesics

inward.

Preincisionalu

nilateralU

SGsubcostalT

APblockwith

1mg/kg

ofbupivacaine

(meanvolume22

mL).

PostoperativeLA

infiltrationof

port

siteswith

1mg/kg

bupivacaine(m

ean

volume21

mL).

Siglower

pain

scores

inTA

Pgroupup

to4h.Similar

numberof

patientsrequired

fentanyl

inPA

CUbutd

ose

was

siglower

inTA

Pgroup

(median0.9vs

1.5μg/kg).

Siglower

opioid

usein

TAPgroupover

8h(m

edian

9.2mgvs

16.9mgIV

morphineequivalents).

Shortertim

eto

dischargefrom

PACUin

TAPgroup(m

edian

65vs

110min).

Chenetal,742013

N=40,laparoscopic

cholecystectom

y.Intraop:

GA+IV

fentanyl

0.5μg/kg

prnPostop:IVmorphine

0.05

mg/kg

prn.NoMMA.

Preincisionalb

ilateralo

blique

subcostalT

APwith

20mLof

0.375%

ropivacaineperside.

IVmorphine0.1mg/kg

post-inductio

nof

GA.

Nosigdifference

inintraop

fentanyluseinTA

Pvs

control

groups

(mean24.5vs

31.3μg)

orinpostop

morphineuse

(0.0mgvs

0.4mg).

Nosigdifference

insedatio

nor

nausea

andvomiting

between

groups.S

igshortertim

eto

extubatio

nin

TAPgroup

(mean10.4minvs

12.4

min).

Contin

uednextpage




TABLE

2.(Con

tinued)

Stud

yStan

dardized

Man

agem

ent

Intervention

Com

parator

Ana

lgesicOutcomes

Other

Outcomes/Com

ments

Ortizetal,752012

N=74,laparoscopic

cholecystectom

y.Intraop:

GA+IV

ketorolac30

mg+IV

fentanyl

50μg

prn+IV

morphineprnatendof

surgery.

Postop:H

ydrocodone

10mg+

acetam

inophen1gevery6h,IV

morphine4mgevery3hprn.

Preincisionalb

ilateralU

SGlateralT

APblocks

with

15mL

of0.5%

ropivacaineperside.

Preincisionalinfiltratio

nof

portsiteswith

total

of20

mLof

0.5%

ropivacaine.

Nosigdifference

inpainscores

betweengroups

upto24

h.Nosigdifference

inintraop

fentanyluseinTA

Pvs

control

groups

(mean237vs

245μg),

intraopmorphineuse(m

ean

5.0vs

5.8mg),or24

hmorphine

use(16.1vs

15.4mg)

Similarincidenceof

nausea

betweengroups.

Bariatricsurgery

Sinhaetal,762013

N=100,laparoscopicgastric

bypass

surgery.Intraop:

GA,noanalgesicdetails

given.Postop:T

ramadol

(route,dose,andinterval

notspecified).NoMMA.

PostoperativebilateralU

SGTA

Pblocks

(not

specified

ifsubcostalo

rlateral)with

20mLof

0.375%

ropivacaineperside.

Noblocks.

Siglower

pain

scores

inTA

Pvs

controlg

roup

upto

24h.Pain

scores

werehighestat1

h(m

edian2vs

4)andlowest

at24

h(0

vs1).S

iglower

tram

adol

usein

TAPvs

controlg

roup

over

24h

(mean9mgvs

48mg).

Shortertim

eto

ambulatio

nin

TAPvs

controlg

roup

(mean6.3hvs

8.0h).

Albrecht

etal,512013

N=57,laparoscopicgastric

bypass

surgery.Intraop:

GA+remifentanilinfusion

+IV

ketorolac30

mg+LA

infiltrationof

portsiteswith

20mLof

0.25%

bupivacaine.

Postop:IVfentanyl

+IV

morphineprnin

PACU.P

Oacetam

inophenevery6h+

POoxycodone5–10

mg

every4hprn,or

IVmorphine2–6mgIV

every

3hprn.

Preincisionalb

ilateralU

SGsubcostalT

APblocks

with

30mLof

0.25%

bupivacaine

perside.

Noblocks.

Similarrestanddynamicpain

scores

upto

48h.Nosig

difference

in24

hopioid

usein

TAPvs

control

group(m

ean32.2

mg

vs35.6mgIV

morphine

equivalents).N

osig

difference

intim

eto

1st

analgesicrequestinTA

Pvs

controlg

roup

(52vs

25min).

Similarratesof

nausea

and

vomiting,pruritusand

length

ofhospitalstay

betweengroups.

Major

gynecologicalsurgery

Carney

etal,772008

N=50,totalabdominal

hysterectomy.Intraop:

GA+IV

morphine

0.15

mg/kg

+PR

diclofenac

100mg+PR

acetam

inophen1g.Postop:

IVPC

Amorphine+PR

acetam

inophen1gevery

6h+PR

diclofenac

100mgevery16

h.

Preincisionalb

ilateralL

MG

TAPblockwith

1.5mg/kg

of0.75%

ropivacaine(m

ax20

mL)perside.

Sham

bilateralT

AP

blocks

with

20mL

0.9%

salin

e.

Siglower

restpain

scores

inTA

Pvs

controlg

roup

at6h(m

edian2vs

4),24h,

(median1vs

3)and36

h(m

edian1vs

3).S

iglower

morphineusein

TAPvs

controlg

roup

over

24h

(mean21.1vs

39.6mg)

andover

48h(26.8vs

55.3mg).S

iglonger

time

to1stP

CAmorphine

requestinTA

Pvs

control

group(m

edian45

vs12.5min).

Siglower

rateof

sedatio

nin

TAPvs

controlg

roup

(37%

vs63%).Similarrateand

severity

ofnausea.




Atim

etal,782011

N=60,totalabdominal


GA+IV

diclofenac

75mg+IV

tram

adol

0.5mg/kg.P

ostop:

IVPC

Atram

adol

+IM

pethidine1mg/kg

prn.

NoMMA.

Group

I:preincisionalb

ilateral

USG

lateralT

APblocks

with

20mL0.25%

bupivacaine

perside.G

roup

II:W

ound

infiltrationwith

20mL0.25%

bupivacaineatendof

surgery.

Sham

bilateralT

AP

blocks

with

20mL

0.9%

salin

e.

Low

errestanddynamicpain

scores,and

tram

adol

usein

TAPvs

controlg

roup

upto

24h.Similarrestand

dynamicpain

scores

inTA

Pvs

infiltrationgroup

upto

4h,butlow

erin

TAP

groupat6hand24

h.Low

ertram

adol

usein

TAP

groupup

to24

h.Siglower

restanddynamicpain

scores

ininfiltrationvs

controlg

roup

upto

4h.

Griffith

setal,792010

N=65,m

ajor

gynecological

surgeryviamidlin

eincision.

Intraop:

GA+IV

morphine

0.1–0.2mg/kg

+IV

acetam

inophen1g+IV

parecoxib40

mg.Postop:

IVPC

Amorphine+PO

/IV

acetam

inophen1gevery6h.

BilateralU

SGlateralT

AP

blocks

with

20mLof

0.5%

ropivacaineperside

after

wound

closure.

Sham

bilateralU

SGTA

Pblocks

with

0.9%

salin

e.

Nosigdifference

inincidence

ofsevere

restor

dynamicpain

(>5/10)at2hor

24h.Nosig

difference

inmorphineusein

TAPvs

controlg

roupsat2h

(mean11.9vs

13.5mg)

or24

h(36vs

34mg).

Nodifference

inincidence

ofnausea,vom

iting,

pruritu

s,or

sedatio

n.

Shin

etal,802011

N=32,gynecologicalsurgery

viatransverse

incision.

Intraop:

GA(TIVA)+

remifentanilinfusion.Postop:

IVPC

Aketorolac-sufentanil.

RescueIV

meperidineor

ketorolacprn.NoMMA.

Preincisionalb

ilateralU

SGlateralT

APblockwith

20mL

0.375%

ropivacaineperside.

NoTA

Pblocks.

Siglower

pain

scores

inTA

Pvs

controlg

roup

at2h(m

ean3.0

vs5.2),24h(m

ean0.9vs

2.2)

butn

ot48

h(0.4

vs1.6).N

osigdifference

inIV

PCAuse

inTA

Pvs

controlg

roup

over

48h(102

mLvs

108mL)

Low

errescue

analgesicusein

TAPvs

controlg

roup.

Sighigher

satisfactionscores

inTA

Pvs

controlg

roup

upto

48h.

Røjskjaer

etal,812015

N=46,totalabdominal


GA

(TIVA)+remifentanil

infusion

+IV

sufentanil

0.3μg/kgatendof

surgery.

Postop:IVPC

Amorphine+

POacetam

inophen1gevery

6h+ibuprofen600mg

every6h.

Preincisionalb

ilateralU

SGlateralT

APblockwith

20mL

0.75%

ropivacaineperside.

Sham

bilateralU

SGTA

Pblocks

with

0.9%

salin

e.

Siglower

restpain

scores

inTA

Pvs

controlg

roup

at2h,and

lower

dynamicpain

scores

at8h.Nosigdifferencesin

restor

dynamicpain

atother

timepoints.N

osigdifference

inmorphineusein

TAPvs

controlg

roup

at24

h(m

ean

36vs

33mg).

Nosigdifferencesbetween

groups

inPA

CUlengthof

stay,timetofirstm

obilization,

nausea

orvomiting.

Gasanova

etal,822013

N=75,totalabdominal


GA+IV

fentanyl

prn+IV

morphine0.1–0.15

mg/kg.

Postop:IVPC

Amorphine.

Group

I:BilateralU

SGlateral

TAPblocks

with

20mL0.5%

bupivacaineperside

atendof

surgery+IV

ketorolac30

mg+

postop

MMA.G

roup

II:T

AP

blocks

atendof

surgeryonly.

Group

III:IntraopIV

ketorolac30

mg.

Postop

MMA:IV

ketorolac30

mg

every6h+PO

acetam

inophen

650mgevery6h.

Nosigdifference

inrestingpain

scores

betweengroups

over

48h.

Sigdifference

indynamicpain

scores

betweengroups

IandIII,

butn

otbetweengroups

IandII,

orIIandIII.Nosigdifference

inmorphineusebetweengroups

at24

h(Ivs

IIvs

III:38.4

vs38.6

vs42.6mg).

Similarincidenceandseverity

ofnausea

andvomiting.

Contin

uednextpage




TABLE

2.(Con

tinued)

Stud

yStan

dardized

Man

agem

ent

Intervention

Com

parator

Ana

lgesicOutcomes

Other

Outcomes/Com

ments

Hotujec

etal,832015

N=64,robotic-assisted

laparoscopicgynecologic-

oncologicsurgery.Intraop:

GA.N

ootheranalgesics

given.Postop:“standard

managem

ent”with

IV+PO

opioidsandNSA

IDs.

Preincisionalu

nilateralU

SGlateralT

APblockwith

30mL

0.25%

bupivacaine.

Sham

TAPblock

with

0.9%

salin

e.Nosigdifference

inpain

scores

at24

hin

TAPvs

controlg

roup

(mean6.44

vs6.97).Nosig

difference

inmorphineuseat

24hin

TAPvs

controlg

roup

(mean64.9

vs69.3

mg).

Nosigdifference

inpatient

satisfactionwith

analgesia

betweengroups.

Torupetal,842015

N=65,robotic-assisted

laparoscopichysterectomy.

Preop:

POacetam

inophen

1g+diclofenac

50mgor

ibuprofen400mg.Intraop:

GA(TIVA)+reminfentanil

infusion

+IV

morphine

0.2mg/kg.Postop:IV

PCA

morphine+PO

acetam

inophen

1gevery6h+diclofenac

50mgor

ibuprofen400mg

every8h.

Preincisionalb

ilateralU

SGlateralT

APblockwith

20mL

0.5%

ropivacaineperside.

Sham

TAPblocks

with

0.9%

salin

e.Nosigdifference

inpain

scores

inTA

Pvs

controlg

roup

at1h

(median4.2vs

4.0)

orover

24h

(2.0vs

2.1).N

osigdifference

inmorphineuseat24

hin

TAPvs

controlg

roup

(median17.5mg

vs17.5mg).

Nosigdifferencesin

nausea

orvomiting

betweengroups.

Amrand

Amin,852011

N=68,totalabdominal


GA+IV

fentanyl

1μg/kgprnPostop:IV

morphine20–50μg/kgprn.

NoMMA.

Group

I:Preincisionalb

ilateral

LMGTA

Pblocks

with

20mL

0.375%

bupivacaine.Group

II:

TAPblocks

atendof

surgery.

Group

III:Sh

amblock.

Siglower

dynamicpain

scores

upto

48hin

both

groupIand

IIvs

groupIII.Siglower

dynamicpain

scores

upto

48h

ingroupIvs

II.S

iglower

intraop

fentanyl

requirem

entsin

groupI

vsIIvs

III(m

ean81

vs170

vs166μg).Siglower

morphine

useat48

hin

both

groupIandII

vsgroupIII(m

ean21

mgvs

33mgvs

66mg).S

iglonger

time

tofirstanalgesicrequestinboth

groupIandIIvs

groupIII(135

vs120vs

102min).

Low

erincidenceof

PONV

ingroupIandIIvs

III

(16%

vs29%

vs67%).

Siglower

incidenceof

chronicpain

ingroupI

vsgroups

IIandIII.

Failu

reof

TAPblock

(absence

ofloss

tocold

sensation)

was

6%.

These

patientswere

excluded

from

analysis.

Sivapurapu

etal,862013

N=52,gynecological

surgery(unspecified).

Intraop:

GA+IV

fentanyl

0.5μg/kgprn.Postop:

IVPC

Amorphine.

NoMMA.

BilateralL

MGTA

Pblock

with

0.3mL/kgof

0.25%

bupivacaineperside

atend

ofsurgery.

Wound

infiltration

with

0.6mL/kgof

0.25%

bupivacaine.

Siglower

pain

scores

inTA

Pvs

infiltrationgroupup

to24

h.Siglower

morphineusein

TAP

vsinfiltrationgroupat24

h(m

ean22

vs29

mg).S

iglonger

timeto

1stanalgesicusein

TAP

vsinfiltrationgroup

(148

vs85

min).




DeOliveira

etal,872011

N=75,laparoscopic


GA+remifentanilinfusion

+IV

hydrom

orphone

10μg/kg+IV

ketorolac

30mg.Postop:IVPC

Ahydrom

orphone+ibuprofen

600mgevery6h.

Group

I:preincisionalb

ilateral

USG

lateralT

APblocks

with

20mL0.5%

ropivacaineperside.

Group

II:p

reincisionalbilateral

USG

lateralT

APblocks

with

20mL0.25%

ropivacaineperside.Group

III:bilateral

sham

blocks

with

20mL0.9%

salin

e.

Siglower

pain

scores

forboth

groups

IandIIvs

groupIII

upto

24h.Siglower

opioid

usein

groupIvs

both

groups

IIandIIIover

24h(m

edian7.5

vs15

vs15

mgIV

morphine

equivalents).

Sigbetterquality

ofrecovery

scores

inboth

groupI

andIIvs

groupIII.

Kaneetal,882012

N=58,laparoscopichysterectomy.

Intraop:

GA+IV

ketorolac

30mg+unspecifiedanalgesics

prnPostop:“Standard”PO

and

IVanalgesics

(unspecified)

BilateralU

SGlateralT

AP

blocks

with

20mL0.5%

ropivacaineperside

attheendof

surgery.

NoTA

Pblocks.

Nosigdifference

inpain

scores

inTA

Pvs

controlg

roup

at2h

(median5vs

6)or

24h(m

edian

5vs

5).N

osigdifference

inmorphineusein

TAPvs

control

groupon

POD0(m

edian11.7vs

11.8mg)

andPO

D1(m

edian

7.5vs

9.0mg).

Nosigdifference

inquality

ofrecovery

scores

betweengroups.

Calleetal,892014

N=197,outpatient

laparoscopic


GA+

remifentanilinfusion+IV

morphineprnPostop:IV

morphineprnin

PACU.P

Oacetam

inophen1gevery

6h+PO

ibuprofen400mg

every8hpost-discharge.

BilateralsurgicalT

AP

blocks

with

1.5mg/kg

bupivacainein

20mL

perside

attheend

ofsurgery.

Sham

TAPblocks

with

20mL0.9%

salin

eperside.

Siglower

pain

scores

atdischarge

inTA

Pvs

controlg

roup

(mean

3.8vs

3.1).N

osigdifferences

inpain

scores

betweengroups

at24

h,48

h,or

72h.Nosig

differencesin

perioperative

morphineusein

TAPvs

control

group(m

ean1.8vs

1.49

mg).

Nosigdifference

inPA

CU

oroveralllengthof

stay

betweengroups.

Bhattacharjee

etal,902014

N=90,totalabdominal


GA+IV

fentanyl

0.5μg/kg

prn+IV

acetam

inophen1g.

Postop:IVtram

adol

2mg/kg

prnfor1std

osethen

every8

h+IV

acetam

inophen1g

every6h.

Preinductionbilateral

LMGTA

Pblocks

with

0.5mL/kg0.25%

bupivacaineperside.

Sham

TAPblocks

wit

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