The document discusses various fascial plane blocks and the mechanism of action of local anesthetics administered in these blocks. It presents several key points:
1. Fascial plane blocks are a heterogeneous group of techniques that deposit local anesthetic in fascial planes surrounding nerves.
2. The exact mechanism of action of fascial plane blocks is unknown, but local anesthetic may act on nerves within the injected plane, adjacent planes, or at distant sites via systemic absorption.
3. Studies show injectate from fascial plane blocks can spread widely, including to adjacent fascial planes and the thoracic paravertebral space, potentially blocking multiple nerve types over large areas.
35. Soft Collagen-Containing
Loose & Dense Fibrous Connective Tissue
Permeates Whole Body
Skin
Superficial fascia
Deep Fascia
(multilayer)
Muscle & related fasciaSuperficial adipose tissue
Deep adipose tissue
Loose connective tissue
What is Fascia?
@amit_pawa
36. Deep Fascia
Multiple layers, Fibrous
Extends through whole body
Target for Fascial plane blocks
Forms sheaths for nerves/vessels/organs
@amit_pawa
37. Deep Fascia Subtypes
Epimysial Aponeurotic
Thin Thick
Specific to 1 muscle May cover several muscles
Adherent to muscle Easily separated
PECS/TAP/Serratus Rectus Sheath/Adductor Canal
38. Deep Fascia Subtypes
Epimysial Aponeurotic
Thin Thick
Specific to 1 muscle May cover several muscles
Adherent to muscle Easily separated
PECS/TAP/Serratus Rectus Sheath/Adductor Canal
39. Lines of Fusion
Distinct fusion points
e.g. Linea Alba/Semilunaris
Creates a “compartment”
(Pathological LOF due to surgery/Adhesions)
Limit Spread - Good (rectus) & Bad!
@amit_pawa
40. Fascial Interconnectivity
Connections between fascia
Many Planes are continuous
Communicate without clear boundaries
Thoracolumbar Fascia
Endothoracic FasciaGluteal Fascia
May help Mechanism of Action
@amit_pawa
41. Not All fascias are the same
Number of layers
Pectoral region - 1
The Limbs - 2 or 3
Middle Thoracolumbar 2 or 3
Function & Mobility More mobile may
increase LA spread
Surrounding structures
Lungs/liver/spleen
IPPV vs SV
@amit_pawa
43. Mechanism of Action?
LA action on:
Nerves in the injected Plane
Nerves in adjacent Planes/tissue
Nerves in distant Planes/tissue
(Systemic Absorption)
Mechanisms of Action Of Fascial Plane Blocks - Jinn KJ, Lirk P, Hollmann M, Schwarz S - Ahead of Print RAPM 2021
@amit_pawa
44. What Nerves might the LA act on?
Cutaneous
Lat. cut. intercostal branches
(Serratus Plane)
Non-Cutaneous - usually silent Nociceptors
Muscle/Ligaments/Joint capsules/Bone/others in fascia
Upregulated in inflammation /injury
Motor Nerves
Some fibres still sensory/nociceptive
Blockade relieves spasm
@amit_pawa
45. @amit_pawa
Nerves in the injected Plane
Hydrodissection via Hydraulic Pressure
“Transmission Belts” & “Decompression planes”
Eg Rectus Sheath, TAP, PECS
46. Plane 1.Plane 2.
Nerves in Adjacent Planes/Tissue
Bulk Flow
E.g. PECS, ESP, MTP
@amit_pawa
Diffusion
concentration gradient
47. @amit_pawa
Nerves at Distant
Sites via
Systemic Absorption
pleura
mus
mus
ESM
ostal nerve
or cutaneous branch of intercostal nerve
Transversus thoracis muscle
ectoral nerves
RLBESP TPVBMTP
acromial artery
Rhomboid
d
Block
53. Nerve elements may lie within the fascia
A & C Fibres - Responsible for nociception?
Wide Dynamic Range neurons
Mechanoreceptors
Do these influence Fascial plane blocks?
4. Local Fascial Innervation
@amit_pawa
54. (a)
(b)
Anaesthesia, 2011, 66, pages 1023–1030
..............................................................................................
rsal extension with an anterior subcostal
ock. (b) Bilateral mid-axillary ultra-
(b)
Figure 8 (a) Bilateral ultrasound via the posterior approac
showing extension along the quadratus lumborum muscle
ORIGINAL ARTICLE
Studies on the spread of local anaesthetic solution in
transversus abdominis plane blocks*
J. Carney,1
O. Finnerty,1
J. Rauf,1
D. Bergin,4
J. G. Laffey2
and J. G. Mc Donnell3
1 Registrar, 2 Professor, 3 Senior Clinical Lecturer, Department of Anaesthesia and Intensive Care Medicine,
4 Senior Clinical Lecturer, Department of Radiology, Galway University Hospitals, Galway, Ireland
Summary
The extent of analgesia provided by transversus abdominis plane blocks depends upon the site of
injection and pattern of spread within the plane. There are currently a number of ultrasound-
guided approaches in use, including an anterior oblique-subcostal approach, a mid-axillary
approach and a more recently proposed posterior approach. We wished to determine whether the
site of injection of local anaesthetic into the transversus abdominis plane affects the spread of the
local anaesthetic within that plane, by studying the spread of a local anaesthetic and contrast
solution in four groups of volunteers. The first group underwent the classical landmark-based
transversus abdominis plane block whereby two different volumes of injectate were studied:
0.3 ml.kg)1
vs 0.6 ml.kg)1
. The second group underwent transversus abdominis plane block using
the anterior subcostal approach. The third group underwent transversus abdominis plane block
using the mid-axillary approach. The fourth group underwent transversus abdominis plane block
using the posterior approach, in which local anaesthetic was deposited close to the antero-lateral
border of the quadratus lumborum. All volunteers subsequently underwent magnetic resonance
imaging at 1, 2 and 4 h following each block to determine the spread of local anaesthetic over time.
The studies demonstrated that the anterior subcostal and mid-axillary ultrasound approaches res-
ulted in a predominantly anterior spread of the contrast solution within the transversus abdominis
plane and relatively little posterior spread. There was no spread to the paravertebral space with the
anterior subcostal approach. The mid-axillary transversus abdominis plane block gave faint contrast
ORIGINAL ARTIC
Studies on the sp
transversus abdom
1 1
Anaesthesia, 2011, 66, pages 1023–1030
..............................................................
US- Guided Posterior TAP spreads to PVS
@amit_pawa
55. SCIENTIFIC ARTICLE
Axillary local anesthetic spread after the thoracic
interfacial ultrasound block --- a cadaveric and
radiological evaluation
Patricia Alfaro de la Torrea
, Jerry Wayne Jones Jr.b
, Servando López Álvarezc
,
Paula Diéguez Garciac
, Francisco Javier Garcia de Migueld
, Eva Maria Monzon Rubioe
,
Federico Carol Boerisf
, Monir Kabiri Sacramentog
, Osmany Duanyh
,
Mario Fajardo Pérezi,∗
, Borja de la Quintana Gordonj
a
Tajo University Hospital, Madrid, Spain
b
University of Tennessee Health Science Center/Regional One Health, College of Medicine, Department of Anesthesiology, TN,
USA
c
Hospital Complexo Hospitalario de A Coru˜na, Coru˜na, Spain
d
Hospital General de Segovia, Departamento de Anestesia, Segovia, Spain
e
Tajo University Hospital, Departamento de Anestesia, Madrid, Spain
f
Hospital Universitario Parc Tauli Sabadell, Sabadell, Spain
g
Hospital Universitario de Guadalajara, Guadalajara, Spain
h
Primary Care and Chronic Pain Management Attending, Department of Veterans Affairs, Muskogee, OK, USA
i
Hospital Universitario de Móstoles, Madrid, Spain
j
Hospital Universitario de Móstoles, Departamento de Anestesia, Madrid, Spain
Received 23 February 2015; accepted 14 April 2015
Available online 22 June 2016
KEYWORDS
Anesthesia,
conduction;
Axilla;
Intercostal muscles;
Brachial plexus block;
Intercostal nerves;
Lymph node excision;
Ultrasonography
Abstract
Background: Oral opioid analgesics have been used for management of peri- and postoperative
analgesia in patients undergoing axillary dissection. The axillary region is a difficult zone to block
and does not have a specific regional anesthesia technique published that offers its adequate
blockade.
Methods: After institutional review board approval, anatomic and radiological studies were
conducted to determine the deposition and spread of methylene blue and local anesthetic
injected respectively into the axilla via the thoracic inter-fascial plane. Magnetic Resonance
Imaging studies were then conducted in 15 of 34 patients scheduled for unilateral breast surgery
that entailed any of the following: axillary clearance, sentinel node biopsy, axillary node biopsy,
or supernumerary breasts, to ascertain the deposition and time course of spread of solution
within the thoracic interfascial plane in vivo.
Rev Bras Anestesiol. 2017;67(6):555---564
REVISTA
BRASILE
ANESTE
SCIENTIFIC ARTICLE
Axillary local anesthetic
cal anesthetic spread after the thoracic interfacial 559
to identify, in the surface plane, the pectoralis muscles,
the toracho-achromial artery and the cephalic vein that lie
between them. In the deep plane, the SAM is identified,
resting on the ribs. The needle is then introduced in-plane
from medial to lateral, and its tip is placed between the
SAM and the External Intercostal muscle at level of sec-
ond rib. Twenty mL of Levobupivacaine 0.25% + Epinephrine
1:200,000 were injected under direct ultrasound visualiza-
tion in real time, fragmenting the total volume, aspirating
every 3 mL to reduce the risk of intravascular injection
and minimizing the patient discomfort on hydrodissection
(Fig. 2A).
Study 1: determination of injectate spread during
SIFB using MRI
The aim of this study was to determine the axillary spread
of the injectate within the SIFB anterior approach. Our
image study consisted of a MRI done immediately after
LA injection. Our radiologist used MRI sequences to show
T2---weighed, fat-suppressed images, making axial and coro-
nal thoracic sections from the supraclavicular regions to the
inframammary crease. The same radiologist, proficient in
thoracic MRI, analyzed the images and issued a report of
the spread of the LA injectate in the interfascial thoracic
“PECS" spreads to
Intercostobrachial
Medial Brachiocutaneous
Lateral Cutaneous Branches T1-3
@amit_pawa
58. ESP Mechanism?
PVB spread by Proxy?
jected dyes into the back muscles after retrolaminar (RL, right) and ESP block (ESP, left).
columbar fascia covering the erector spinae muscle was revealed. (b) The muscle fibre
The spread pattern of the dyes in the vertebral laminae was seen after removal of all bac
ocostalis; Lo, longissimus thoracis).
(b)
(c)
Anaesthesia 2018, 73, 1244–1250
Original Article
Comparison of injectate spread and nerve involvement
between retrolaminar and erector spinae plane blocks in
the thoracic region: a cadaveric study
H.-M. Yang,1
Y. J. Choi,2
H.-J. Kwon,3
J. O,3
T. H. Cho3
and S. H. Kim4
1 Assistant Professor, 2 Instructor, 3 Research Assistant, Department of Anatomy, 4 Associate Professor, Department of
Anaesthesiology and Pain Medicine, Anaesthesia and Pain Research Institute, Yonsei University College of Medicine,
Seoul, Korea
Summary
Although different injection locations for retrolaminar and erector spinae plane blocks have been described,
the two procedures have a similar anatomical basis. In this cadaveric study we compared anatomical spread of
dye in the thoracic region following these two procedures. Following randomisation, 10 retrolaminar blocks
and 10 erector spinae plane blocks were performed on the left or right sides of 10 unembalmed cadavers. For
each block, 20 ml of dye solution was injected at the T5 level. The back regions were dissected and the
involvement of the thoracic spinal nerve was also investigated. Twenty blocks were successfully completed. A
consistent vertical spread, with deep staining between the posterior surface of the vertebral laminae and the
overlaying transversospinalis muscle was observed in all retrolaminar blocks. Moreover, most retrolaminar
blocks were predominantly associated with fascial spreading in the intrinsic back muscles. With an erector
spinae plane block, dye spread in a more lateral pattern than with retrolaminar block, and fascial spreading in
the back muscles was also observed. The number of stained thoracic spinal nerves was greater with erector
spinae plane blocks than with retrolaminar blocks; median 2.0 and 3.5, respectively. Regardless of technique,
the main route of dye spread was through the superior costotransverse ligament to the ipsilateral paravertebral
space. Although erector spinae plane blocks were associated with a slightly larger number of stained thoracic
spinal nerves than retrolaminar blocks, both techniques were consistently associated with posterior spread of
Anaesthesia 2018 doi:10.1111/anae.14408
Original Article
Comparison of injectate spread and ner
between retrolaminar and erector spina
the thoracic region: a cadaveric study
H.-M. Yang,1
Y. J. Choi,2
H.-J. Kwon,3
J. O,3
T. H. Cho3
and S. H
Anaesthesia 2018, 73, 1244–1250
@amit_pawa
59. ESP Mechanism?
PVB spread by Proxy?
jected dyes into the back muscles after retrolaminar (RL, right) and ESP block (ESP, left).
columbar fascia covering the erector spinae muscle was revealed. (b) The muscle fibre
The spread pattern of the dyes in the vertebral laminae was seen after removal of all bac
ocostalis; Lo, longissimus thoracis).
(b)
(c)
Anaesthesia 2018, 73, 1244–1250
Original Article
Comparison of injectate spread and nerve involvement
between retrolaminar and erector spinae plane blocks in
the thoracic region: a cadaveric study
H.-M. Yang,1
Y. J. Choi,2
H.-J. Kwon,3
J. O,3
T. H. Cho3
and S. H. Kim4
1 Assistant Professor, 2 Instructor, 3 Research Assistant, Department of Anatomy, 4 Associate Professor, Department of
Anaesthesiology and Pain Medicine, Anaesthesia and Pain Research Institute, Yonsei University College of Medicine,
Seoul, Korea
Summary
Although different injection locations for retrolaminar and erector spinae plane blocks have been described,
the two procedures have a similar anatomical basis. In this cadaveric study we compared anatomical spread of
dye in the thoracic region following these two procedures. Following randomisation, 10 retrolaminar blocks
and 10 erector spinae plane blocks were performed on the left or right sides of 10 unembalmed cadavers. For
each block, 20 ml of dye solution was injected at the T5 level. The back regions were dissected and the
involvement of the thoracic spinal nerve was also investigated. Twenty blocks were successfully completed. A
consistent vertical spread, with deep staining between the posterior surface of the vertebral laminae and the
overlaying transversospinalis muscle was observed in all retrolaminar blocks. Moreover, most retrolaminar
blocks were predominantly associated with fascial spreading in the intrinsic back muscles. With an erector
spinae plane block, dye spread in a more lateral pattern than with retrolaminar block, and fascial spreading in
the back muscles was also observed. The number of stained thoracic spinal nerves was greater with erector
spinae plane blocks than with retrolaminar blocks; median 2.0 and 3.5, respectively. Regardless of technique,
the main route of dye spread was through the superior costotransverse ligament to the ipsilateral paravertebral
space. Although erector spinae plane blocks were associated with a slightly larger number of stained thoracic
spinal nerves than retrolaminar blocks, both techniques were consistently associated with posterior spread of
Anaesthesia 2018 doi:10.1111/anae.14408
Original Article
Comparison of injectate spread and ner
between retrolaminar and erector spina
the thoracic region: a cadaveric study
H.-M. Yang,1
Y. J. Choi,2
H.-J. Kwon,3
J. O,3
T. H. Cho3
and S. H
Anaesthesia 2018, 73, 1244–1250
“the amount of dye within the paravertebral space following both
retrolaminar and ESP injections seemed to be too small to allow for upward
or downward flow.”
@amit_pawa
63. What can we say so far?
There is limited evidence of “By-Proxy” spread
Variation exists in Cadaver studies too!
Cadaver results may not relate to “Real Life”
(Mechanical Ventilation/Movement)
@amit_pawa
65. Fascial Plane Blocks can be
Unpredictable
Inconsistent Effect
Inconsistent Efficacy
Inconsistent Evidence
Dense Neural Blockade is Rare
@amit_pawa
66. LA Spread Affected by…
Thickness of fascia
Thick fascia - easy to identify, limited diffusion,
“contains LA”, but spread limited
Thin fascia - harder to identify, better diffusion,
LA “spills out” so spread variable
@amit_pawa
68. Is this good enough?
@amit_pawa
Less Ideal Blocks
69. Even when you get in the correct
plane - does the LA stay there?
Yang H, Kim SH Injectate spread in interfascial plane block: a microscopic finding
Regional Anesthesia & Pain Medicine Published Online First: 05 July 2019.
doi: 10.1136/rapm-2019-100693
@amit_pawa
70. Even when you get in the correct
plane - does the LA stay there?
Yang H, Kim SH Injectate spread in interfascial plane block: a microscopic finding
Regional Anesthesia & Pain Medicine Published Online First: 05 July 2019.
doi: 10.1136/rapm-2019-100693
@amit_pawa
71. Even when you get in the correct
plane - does the LA stay there?
Yang H, Kim SH Injectate spread in interfascial plane block: a microscopic finding
Regional Anesthesia & Pain Medicine Published Online First: 05 July 2019.
doi: 10.1136/rapm-2019-100693
“The Fascial plane is not a closed space”
"Injectate spread into the internal oblique &
transversus abdominus muscle via the Perimysium”
Could this affect the amount of LA
available to act?
@amit_pawa
72. Receptors within Fascia
Somatic Nerves (Sensory/Motor) - variable path
Sympathetic
Nerves to the Fascia - “Fasciatome”
Could action on last two subtypes
explain successful block without
dermatomal loss of sensation?
73. Does Inconsistent Dermatomal
sensory loss = Failed Block?
Analgesia & Opioid Reduction still evident
Differential block - (C >A-delta fibres)?
If pt derives benefit, does it matter?
PROM & Minimum Clinically Important Difference
(MCID) in QoR
Mechanisms of Action Of Fascial Plane Blocks - Jinn KJ, Lirk P, Hollmann M, Schwarz S - Ahead of Print RAPM 2021
@amit_pawa
74. Does Inconsistent Dermatomal
sensory loss = Failed Block?
Anatomical Cutaneous innervation is complex
Overlapping innervation across midline
Interindividual variation
Pharmacokinetic variability & concentration of LA at target
Accuracy of deposition & Variability of spread
Non-cutaneous contributions to nociception
Mechanisms of Action Of Fascial Plane Blocks - Jinn KJ, Lirk P, Hollmann M, Schwarz S - Ahead of Print RAPM 2021
@amit_pawa
75. How Can We Improve Efficacy?
Deposit LA closer to target- (e.g. Rectus > Lat TAP)
Inject at more than 1 site?
Increase Concentration of LA ?
Increase Mass of LA deposited ?
Use Epinephrine?
Catheters - Intermittent Boluses
Mechanisms of Action Of Fascial Plane Blocks - Jinn KJ, Lirk P, Hollmann M, Schwarz S - Ahead of Print RAPM 2021
@amit_pawa
80. What do these say?
QL/ESP fascial plane blocks:
1. Reduce Pain Scores
2.Reduce Opioid Requirements
When compared to SYSTEMIC analgesia alone
@amit_pawa
84. PECS/Serratus/ESP -significant benefit in breast/thoracics
Similar to Th PVB (PECS)
Their role in trauma & cardiac surgery is holds great potential
@amit_pawa
89. Increasing Access to RA
Much of USGRA - daunting to uninitiated
Idea of Fascial Plane Blocks is Simple
Superficial Planes - eg Rectus/PECS/TAP
Similar technique - Split the plane
Focus on “Plan A blocks” - Build from there
@amit_pawa
90. Promote competence
in a few HIGH VALUE
“Plan A” Blocks
Increase Patient
access to RA
Anatomical Location Plan A Block
Shoulder Interscalene
Upper limb below Shoulder Axillary
Hip Femoral Nerve
Knee Adductor Canal
Foot & Ankle Popliteal Sciatic
Chest Wall Erector Spinae Plane
Abdominal Midline Rectus Sheath
Endorsed
@amit_pawa
95. Conclusions
@amit_pawa
1. Fascial Plane Blocks are Heterogenous
2. Unknown Mechanism of Action
3. Unpredictable efficacy
4. May have a role where No Epi/PVB
5. Increasing RA Delivery
96. Why We Need Fascial Plane Blocks In Our Toolkit
We need Alternatives when we can’t Perform classic
blocks, or when they fail
@amit_pawa
Regional Anaesthesia is part of MMA
We need to increase RA delivery so more patients
benefit
Some fascial plane blocks are simple to teach &
perform