Concepts in Fascial Plane Blocks - What Every Anaesthetist Needs to Know

1. Concepts In Fascial Plane Blocks @amit_pawa Dr Amit Pawa What every Anaesthetist needs to know

2. In the next 30mins… My Opinions Some Concepts Some Evidence Take home points @amit_pawa

3. Nerve Block Evolution @amit_pawa

4. Landmark-Guided Blocks @amit_pawa

5. @amit_pawa

6. PNS-Guided Blocks @amit_pawa

7. @amit_pawa

8. US-Guided Blocks @amit_pawa

9. Are we getting too close? @amit_pawa

10. With (Fascial) Plane Blocks… @amit_pawa

11. Maybe this is close enough? @amit_pawa

12. @amit_pawa

13. Have we gone too far? @amit_pawa

14. Have we gone too far?

15. The Innovators @amit_pawa

16. Fascial Plane Blocks TAP QLB 1/2/3 Femoral Triangle Block PECS 1/11 Serratus RISS TQL ESP BD-TAP @amit_pawa RLB MTP SSPSPSPS Shamrock Lumbar Plexus SPEDI Clavipectoral iPack PENG ACB MICB

17. @amit_pawa Perhaps this is part of the problem! Too many blocks Inconsistent NOMENCLATURE

18. Important Reference @amit_pawa Reg Anesth Pain Medicine Volume 43, Number 4, May 2018 @kaohesham @EMARIANOMD

19. The Science… @amit_pawa

20. 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

21. Deep Fascia Multiple layers Extends through whole body Target for Fascial plane blocks Forms sheaths for nerves/vessels/organs Independent of muscle below @amit_pawa

22. How might fascial plane blocks work? @amit_pawa

23. 1. Transmission belts LA “seeks” decompression planes via potential spaces ESP block becomes Serratus/PECS II @amit_pawa

24. 1. Transmission belts @amit_pawa

25. 1. Transmission belts @amit_pawa

26. Parietal pleura Ventral ramus Dorsal ramus ESM Lateral cutaneous branch of intercostal nerve Anterior cutaneous branch of intercostal nerve Transversus thoracis muscle Pec. major Pec. minor Inn IMInt IMExt IM Serratus anterior muscle Latissimus dorsi muscle Lateral and medial pectoral nerves PEC I PEC II SAP Blocks Pecto-Intercostal Fascial Block RLBESP TPVBMTP Pectoral branch of thoracoacromial artery SIFB Rhomboid Rhomboid Intercostal Block Subserratus Plane Block RISS Dr Ann Barron @Ann_Barron1 PIFB: Pecto-Intercostal Fascial Block SIFB: Serratus intercostal Fascial block SAP: Serratus Anterior Plane RISS: Rhomboid Intercostal & SubSerratus Plane Block MTP: Mid-Point Transverse Process to Pleura ESP: Erector Spinae TPVB: Thoracic ParaVertebral Block RLB: RetroLaminar Block @amit_pawa

27. Parietal pleura Lateral cutaneous branch of intercostal nerve Anterior cutaneous branch of intercostal nerve Transversus thoracis muscle Pec. major Pec. minor Latissimus dorsi muscle Lateral and medial pectoral nerves PEC I PEC II SAP Blocks Pecto-Intercostal Fascial Block Pectoral branch of thoracoacromial artery SIFB

28. 2.“Back-Door” ? @amit_pawa “by-proxy”

29. SCTL PVB @amit_pawa SCTL SCTL SCTL

30. SCTL ESP @amit_pawa SCTL SCTL SCTL

31. SCTL Paravertebral-by-Proxy? @amit_pawa

32. 3. Biomechanical properties @amit_pawa Fascia Is Dynamic

33. 3. Biomechanical properties Pumping mechanism due to muscle tendons? Contractile elements within fascia? -> Variable/extensive dermatomal spread? Effect of: Depth of Anaesthesia & Muscle Relaxation? @amit_pawa

34. Nerve elements may lie within the fascia A & C Fibres Wide Dynamic Range neurons Mechanoreceptors Do these influence Fascial plane blocks? 4. Local Fascial Innervation @amit_pawa

35. Not All fascias are the same Number of layers Pectoral region - 1 The Limbs - 2 or 3 Middle Thoracolumbar 3 Function & Mobility More mobile may increase LA spread Surrounding structures Lungs/liver/spleen IPPV vs SV @amit_pawa

36. @amit_pawa Reliability of finding the plane…

37. Clear Right?! @amit_pawa Reliability of finding the plane…

38. 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

39. 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

40. There’s a lot we DON’T know @amit_pawa

41. What can we say so far? Not all fascial plane blocks are equal Not all fascial plane blocks work (the same way!) Fascial plane blocks have variable efficacy Identifying the correct plane is not always easy (“Seeker” solution) @amit_pawa

42. Evidence?…@amit_pawa

43. (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 resulted 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

44. 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 Coruña, Coruña, 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 second rib. Twenty mL of Levobupivacaine 0.25% + Epinephrine 1:200,000 were injected under direct ultrasound visualization 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

45. Injectate Spread With the TQL Block Figure 3. Pathway. A, Visualization of spread of dye posterior to the transversalis fascia from the lumbar position and into the thoracic paravertebral space. The 2 tweezers are placed posterior to both arcuate ligaments. The dye spreads posterior to the medial and lateral arcuate ligaments (blue circle). The Magenta dotted line indicates diaphragm. B, Red arrow: Green dye is visualized posterior to endothoracic fascia within the thoracic cage. The magenta dotted line indicates the diaphragm; PM, psoas major. BACKGROUND: The spread of injectate resulting from a transmuscular quadratus lumborum (TQL) block and a transverse oblique paramedian (TOP) TQL block has never been examined. The aim of this cadaveric study was to investigate by which pathway the injectate spreads cephalad into the thoracic paravertebral space and which nerves were dyed by the injectate cephalad and caudad to the diaphragm when performing a TQL and a TOP TQL block. We also aimed to investigate whether the thoracic and lumbar sympathetic trunks as well as the lumbar plexus were covered by the injectate. METHODS: Ultrasound-guided bilateral TQL and TOP TQL injections were administered in 8 cadavers. A total of 16 injections were performed. With the TQL injection, the curvilinear transducer was oriented in the transverse plane above the iliac crest at the posterior axillary line to identify the Shamrock sign. With the TOP TQL injection, the same transducer was placed with a TOP orientation 3 cm lateral to the L2 spinous process to identify the L2 transverse process and the adjoining quadratus lumborum muscle. For both techniques, the needle was advanced in-plane to the transducer, with the end point in the interfascial plane between the quadratus lumborum and psoas major muscles. Thirty milliliters of dye solution was injected bilaterally for each technique. The spread of the dye was evaluated by subsequent dissection. RESULTS: In all successful injections, the dye was seen to spread into the thoracic paravertebral space and the intercostal spaces to surround the somatic nerves and the thoracic sympathetic trunk. The main pathway of spread of injectate was posterior to the medial and lateral arcuate ligaments. Caudad to the diaphragm, the injected dye surrounded the subcostal, iliohypogastric, and ilioinguinal nerves in all cases, whereas the genitofemoral and lateral femoral cutaneous nerves were dyed in a varying degree. No dye was seen to surround the lumbar plexus, femoral nerve, or lumbar sympathetic trunk. The pattern of spread was similar with the TQL and TOP TQL injections. CONCLUSIONS: The spread of injectate with the TQL and TOP TQL approaches is cephalad from the lumbar point of administration between the quadratus lumborum and psoas major muscles, predominantly via a pathway posterior to the arcuate ligaments and into the thoracic paravertebral space to reach the somatic nerves and the thoracic sympathetic trunk in the intercostal and paravertebral spaces. The lumbar plexus and lumbar sympathetic trunk are not affected. (Anesth Analg 2017;125:303–12) The Pathway of Injectate Spread With the Transmuscular Quadratus Lumborum Block: A Cadaver Study Mette Dam, MD,* Bernhard Moriggl, MD, PhD,† Christian K. Hansen, MD,* Romed Hoermann,† Thomas F. Bendtsen, MD, PhD,‡ and Jens Børglum, MD, PhD* CHRONIC PAIN MEDICINEORIGIN Section Editor: Honorio T. Benzon Copyright © 2017 International Anesthe July 2017 • Volume 125 • Number 1nesthesia Research Society. Unauthorized reproduction of this article is prohibited. a.org ANESTHESIA & ANALGESIA TQL spreads to PVS & Sympathetic trunk Lumbar plexus was not stained @amit_pawa T10. As with the TQL approach, the ventral rami of the spinal nerves were dyed as proximal as the cranial distribution of dye spread. The thoracic sympathetic trunk was dyed in 100% (CI, 0.39–1.00) of the cases. Caudad to the diaphragm, the subcostal, iliohypogastric, and ilioinguinal nerves were dyed in 100% (CI, 0.39–1.00) of the cases, whereas the genitofemoral and lateral femoral cutaneous nerves were dyed to a varying degree (Table 2). The lumbar plexus was never dyed within the psoas major muscle; nor was the femoral nerve or the lumbar sympathetic trunk. In addition, no dye was detected intraperito- neally, and there was no dye observed spreading into the transversus abdominis plane. evaluate the QLB.1,4,18,20 The main dye to the t posterior to the majority was posteri phragmatic to be able to The vent nerves) wer the dorsal ra dye reachin

46. mixture comprising 10 mL of an iodinated hexol (Omnipaque 300; GE Healthcare, ), diluted in 85 mL of 0.9% sodium chloride collimation, 1.2 mm. Images were reconstructed using a soft tissue algorithm at 3 mm slice thickness at 3-mm intervals. All images were reviewed by a consultant radiologist. Spread of nsional CT reconstruction of injectate spread (darker area) after injection at the T5 level deep to erector spinae muscle. caudal spread from T1 to T8. The solid arrows indicate the penetration of dye beyond the costotransverse junction intertransverse spaces. d Pain Medicine • Volume 41, Number 5, September-October 2016 ESP Block in Thoracic Pain Twenty milliliters of a mixture comprising 10 mL of an iodinated contrast material, iohexol (Omnipaque 300; GE Healthcare, Princeton, New Jersey), diluted in 85 mL of 0.9% sodium chloride with 5 mL of methylene blue dye was injected. Within 20 minutes of completing the injections, cadaver 2 was transferred to a 128-slice multidetector CT scanner (Siemens Flash CT; Siemens Healthcare) where abdominal and thoracic imaging was performed to radio- graphically assess the distribution of injectate. Images were acquired using routine clinical imaging protocols with the following parameters: kilovolt (peak), 120; effective milliampere- second, 210; rotation time, 0.5 seconds; pitch, 0.8; and detector collimation, 1.2 mm. Images were recon tissue algorithm at 3 mm slice thickness images were reviewed by a consultant r injectate was assessed primarily upon rev set supplemented with multiplanar images caudal spread of injectate from C7 to T8 T8 on the left, occurring in a paraspinous transverse processes anteriorly and the erec teriorly (Fig. 5). Lateral spread extended t verse processes at all levels, and slightly bey junctions at levels T3 to T6 on the right an FIGURE 6. Dissection of the right side of cadaver 2 after an ultrasound-guided ESP block and dye injection deep to e Trapezius and rhomboid muscles have been removed. The longissimus thoracis portion of the erector spinae muscle cranially and dense staining of its anterior (deep) surface is visible. The external intercostal muscle, internal intercosta surrounding tissues are also heavily stained. Dye has penetrated deep to these layers and through the costotransvers The Erector Spinae Plane Block A Novel Analgesic Technique in Thoracic Neuropathic Pain Mauricio Forero, MD, FIPP,* Sanjib D. Adhikary, MD,† Hector Lopez, MD,‡ Calvin Tsui, BMSc,§ and Ki Jinn Chin, MBBS (Hons), MMed, FRCPC|| oracic neuropathic pain is a debilitating condition that is sponsive to oral and topical pharmacotherapy. The benefit al nerve block procedures is unclear due to a paucity of ev- invasiveness of the described techniques. In this report, we el interfascial plane block, the erector spinae plane (ESP) uccessful application in 2 cases of severe neuropathic pain ng from metastatic disease of the ribs, and the second from ultiple rib fractures). In both cases, the ESP block also pro- sive multidermatomal sensory block. Anatomical and radio- ation in fresh cadavers indicates that its likely site of action and ventral rami of the thoracic spinal nerves. The ESP omise as a simple and safe technique for thoracic analgesia neuropathic pain as well as acute postsurgical or posttrau- in Med 2016;41: 00–00) hic pain is a common chronic pain condition with tiologies, including surgery, trauma, and diseases s zoster, diabetes, and cancer.1 It is notoriously diffi- Case 1 A 67-year-old man, weight 116 kg and height 188 cm [body mass index (BMI), 32.8 kg/m2 ] with a history of heavy smoking and paroxysmal supraventricular tachycardia controlled on ateno- lol, was referred to the chronic pain clinic with a 4-month history of severe left-sided chest pain. A magnetic resonance imaging scan of his thorax at initial presentation had been reported as nor- mal, and the working diagnosis at the time of referral was post- herpetic neuralgia. He reported constant burning and stabbing neuropathic pain of 10/10 severity on the numerical rating score (NRS), radiating from his spine into the anterior chest wall, mainly at T5 and extending several dermatomes inferiorly. There was significant sleep disturbance and impairment of quality of life. Phys- ical examination revealed allodynia and hyperesthesia over the affected dermatomes with a primary trigger point over the T5 der- matome 3 to 4 cm lateral to the neuraxial midline. Pain management up to that point had included pregabalin (600 mg daily at the time of consultation), nonsteroidal anti-inflammatory drugs, baclofen, fluoxetine, and marijuana with no improvement. Several different opioids had been tried but all had to be stopped due to Within several minutes, the patient reporte diminished significantly, and a full assessment sensory block was performed 2 hours later. By tient had obtained complete relief of pain, with There was an area of diminished sensation to p Hospital, McL 2-405, 399 Bathurst St, Toronto, Ontario, Canada M5T 2S8 (e‐mail: gasgenie@gmail.com). The authors declare no conflict of interest. Copyright © 2016 by American Society of Regional Anesthesia and Pain Medicine ISSN: 1098-7339 DOI: 10.1097/AAP.0000000000000451 Regional Anesthesia and Pain Medicine • Volume 41, Number 5, September-October 2016 Copyright © 2016 American Society of Regional Anesthesia and Pain Medicine. Unauthorized reproduction of this a ESP injection travels up & down & spreads to PVS @amit_pawa

47. 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

48. Dorsal Rami Spread only? ESP Mechanism?Downloadedfromhttps://journals.lww.com/rapmbyBhDMf5ePHKav1zEoum1tQfN4a+kJLhEZgbsIHo4XMi0hCywCX1AWnYQp/Il A Cadaveric Study Investigating the Mechanism of Action of Erector Spinae Blockade Jason Ivanusic, PhD,* Yasutaka Konishi, MD,†‡ and Michael J. Barrington, PhD, MBBS, FANZCA†§ Background and Objectives: Erector spinae block is an ultrasound- guided interfascial plane block first described in 2016. The objectives of this cadaveric dye injection and dissection study were to simulate an erector spinae block to determine if dye would spread anteriorly to the involve origins of the ventral and dorsal branches of the spinal nerves. Methods: In 10 unembalmed human cadavers, 20 mL of 0.25% methylene blue dye was injected bilaterally into the plane between the fifth thoracic transverse process and erector spinae muscle. An in-plane ultrasound-guided technique with the transducer orientated longitudinally was used. During dissection, superficial and deep muscles were identified, and extent of dye spread was documented in cephalocaudal and lateral directions. The ventral and dorsal rami of spinal nerves and dorsal root ganglion at each level were examined to determine if they were stained by dye. Results: There was extensive cephalocaudad and lateral spread of dye deep and superficial to the erector spinae muscles. Except for 1 injection (from 20), the ventral rami were not stained by the dye. In only 2 injections did the dye track posteriorly through the costotransverse foramen to the dorsal root ganglion. In all other cases, the dorsal root ganglia were not in- volved in the dye injection. The dye stained the dorsal rami posterior to the costotransverse foramen. Conclusions: There was no spread of dye anteriorly to the paravertebral space to involve origins of the ventral and dorsal branches of the thoracic spinal nerves. Dorsal ramus involvement was posterior to the costotransverse foramen. (Reg Anesth Pain Med 2018;43: 567–571) In clinical reports, ESB resulted in extensive cutaneous sensory block indicating both ventral and dorsal spinal rami involvement.1 Furthermore, a cadaveric dye injection and dissection in 1 cadaver reported spread of dye in the vicinity of the origins of the ventral and dorsal rami of the spinal nerves.1 Hence, ESB has been described as a technically simpler alternative to ultrasound- guided paravertebral block with a similar mechanism of action. In addition, ESB is likely to be safer than paravertebral blockade because the injection is in a plane remote from critical structures such as the pleura, and thus there has been significant clinical interest in this block. Therefore, the objective of this current cadaveric experiment was to simulate an ESB to determine if dye would spread anteriorly to the paravertebral space to involve the origins of the ventral and dorsal branches of the thoracic spinal nerves. The extents of craniocaudal and medial-to-lateral spread of the dye were also documented. METHODS This project was approved by the Human Research Ethics Committee, University of Melbourne (Project within Program Ethics ID 1441811.3). Ten unembalmed human cadavers were obtained through the body donor program of the Department of Anatomy and Neuroscience. None of the specimens were frozen before the interventions were performed. Before commencement REGIONAL ANESTHESIA AND ACUTE PAIN ORIGINAL ARTICLE tion. A skin incision was made along the midlin processes from above C7 to the lower lumbar ver reflected laterally to expose the posterior thoracic Superficial muscles (trapezius, latissimus dorsi were individually identified and reflected. T muscles were identified and removed at their the extent of dye spread deep and superficial t explored and documented. The extent of cepha (e‐mail: Michael.Barrington@svha.org.au). Funding was from departmental resources only. Support was provided by the Imaging and Posters Unit at the Department of Anatomy and Neuroscience, University of Melbourne, and Anastasia Arsenoulis from FUJIFILM SonoSite, Inc, which provided an ultrasound machine. The authors declare no conflict of interest. Copyright © 2018 by American Society of Regional Anesthesia and Pain Medicine ISSN: 1098-7339 DOI: 10.1097/AAP.0000000000000789 Regional Anesthesia and Pain Medicine • Volume 43, Number 6, August 2018 Copyright © 2018 American Society of Regional Anesthesia and Pain Medicine. Unauthorized reproduction of this a @amit_pawa

49. Dorsal Rami Spread only? ESP Mechanism?Downloadedfromhttps://journals.lww.com/rapmbyBhDMf5ePHKav1zEoum1tQfN4a+kJLhEZgbsIHo4XMi0hCywCX1AWnYQp/Il A Cadaveric Study Investigating the Mechanism of Action of Erector Spinae Blockade Jason Ivanusic, PhD,* Yasutaka Konishi, MD,†‡ and Michael J. Barrington, PhD, MBBS, FANZCA†§ Background and Objectives: Erector spinae block is an ultrasound- guided interfascial plane block first described in 2016. The objectives of this cadaveric dye injection and dissection study were to simulate an erector spinae block to determine if dye would spread anteriorly to the involve origins of the ventral and dorsal branches of the spinal nerves. Methods: In 10 unembalmed human cadavers, 20 mL of 0.25% methylene blue dye was injected bilaterally into the plane between the fifth thoracic transverse process and erector spinae muscle. An in-plane ultrasound-guided technique with the transducer orientated longitudinally was used. During dissection, superficial and deep muscles were identified, and extent of dye spread was documented in cephalocaudal and lateral directions. The ventral and dorsal rami of spinal nerves and dorsal root ganglion at each level were examined to determine if they were stained by dye. Results: There was extensive cephalocaudad and lateral spread of dye deep and superficial to the erector spinae muscles. Except for 1 injection (from 20), the ventral rami were not stained by the dye. In only 2 injections did the dye track posteriorly through the costotransverse foramen to the dorsal root ganglion. In all other cases, the dorsal root ganglia were not in- volved in the dye injection. The dye stained the dorsal rami posterior to the costotransverse foramen. Conclusions: There was no spread of dye anteriorly to the paravertebral space to involve origins of the ventral and dorsal branches of the thoracic spinal nerves. Dorsal ramus involvement was posterior to the costotransverse foramen. (Reg Anesth Pain Med 2018;43: 567–571) In clinical reports, ESB resulted in extensive cutaneous sensory block indicating both ventral and dorsal spinal rami involvement.1 Furthermore, a cadaveric dye injection and dissection in 1 cadaver reported spread of dye in the vicinity of the origins of the ventral and dorsal rami of the spinal nerves.1 Hence, ESB has been described as a technically simpler alternative to ultrasound- guided paravertebral block with a similar mechanism of action. In addition, ESB is likely to be safer than paravertebral blockade because the injection is in a plane remote from critical structures such as the pleura, and thus there has been significant clinical interest in this block. Therefore, the objective of this current cadaveric experiment was to simulate an ESB to determine if dye would spread anteriorly to the paravertebral space to involve the origins of the ventral and dorsal branches of the thoracic spinal nerves. The extents of craniocaudal and medial-to-lateral spread of the dye were also documented. METHODS This project was approved by the Human Research Ethics Committee, University of Melbourne (Project within Program Ethics ID 1441811.3). Ten unembalmed human cadavers were obtained through the body donor program of the Department of Anatomy and Neuroscience. None of the specimens were frozen before the interventions were performed. Before commencement REGIONAL ANESTHESIA AND ACUTE PAIN ORIGINAL ARTICLE tion. A skin incision was made along the midlin processes from above C7 to the lower lumbar ver reflected laterally to expose the posterior thoracic Superficial muscles (trapezius, latissimus dorsi were individually identified and reflected. T muscles were identified and removed at their the extent of dye spread deep and superficial t explored and documented. The extent of cepha (e‐mail: Michael.Barrington@svha.org.au). Funding was from departmental resources only. Support was provided by the Imaging and Posters Unit at the Department of Anatomy and Neuroscience, University of Melbourne, and Anastasia Arsenoulis from FUJIFILM SonoSite, Inc, which provided an ultrasound machine. The authors declare no conflict of interest. Copyright © 2018 by American Society of Regional Anesthesia and Pain Medicine ISSN: 1098-7339 DOI: 10.1097/AAP.0000000000000789 Regional Anesthesia and Pain Medicine • Volume 43, Number 6, August 2018 Copyright © 2018 American Society of Regional Anesthesia and Pain Medicine. Unauthorized reproduction of this a nusic et al Regional Anesthesia and Pain Medicine • Volume 43, Number 6, August 2018 @amit_pawa

50. Spread to Th PV Space in 4 out of 11 cadavers (T2 injection) Unpredictable Spread Anesthesia & Analgesia. Publish Ahead of Print():, MAY 15, 2019 DOI: 10.1213/ANE.0000000000004187 ESP Mechanism? @amit_pawa

51. ESP/MICB vs ThPVB PV Spread in BOTH MICB > ESP 2019 - Pub ahead of print @amit_pawa

52. August 2019 Journal of Pain Research Volume 12:2597-2613

53. 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

54. What about clinical studies? @amit_pawa

55. 0 50 100 150 200 250 300 350 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 Publications per year QLB TEA TPVB Serratus Plane Pecs ESP TEA TPVB QLB SAPB PECS ESP Publications per year @amit_pawa

56. QL Clinical Studies Anesth Analg. 2018 Feb;126(2):559-565. doi: 10.1213/ANE.0000000000002648 @amit_pawa Br J Anaesth. 2019 Aug;123(2):e350-e358. doi: 10.1016/j.bja.2019.04.054. Epub 2019 May 30

57. ESP Clinical studies @amit_pawa Indian J Anaesth. 2018 Jan; 62(1): 75–78 Reg Anesth Pain Med. 2017 May/Jun;42(3):372-376

58. ESP Clinical studies @amit_pawa Indian J Anaesth. 2018 Jan; 62(1): 75–78 Reg Anesth Pain Med. 2017 May/Jun;42(3):372-376

59. 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

60. What About Meta-analyses/SR? @amit_pawa

61. What do these say? PECS blocks (mostly PECS II) 1. Reduce Pain Scores 2. Reduce Opioid Requirements 3. May be as effective as Th PVB?… @amit_pawa

62. @amit_pawa

63. Fascial Plane Blocks Many unanswered questions Unknown mechansims of action Cadaveric studies do not reflect “real life” Clinical studies demonstrate benefit - variable efficacy Need more evidence More Likely to be performed by the less experienced @amit_pawa

64. Fascial Plane Blocks Many unanswered questions Unknown mechansims of action Cadaveric studies do not reflect “real life” Clinical studies demonstrate benefit - variable efficacy Need more evidence More Likely to be performed by the less experienced Because, compared to TEA/PVB… @amit_pawa

65. Fascial Plane Blocks May be EASIER to site May be SAFER to site - and may work “By Proxy” May be QUICKER to site SHOULD be combined with Multimodal Analgesics Are HERE TO STAY! @amit_pawa

66. Make RA Accessible Anatomical Nomenclature Ensure RA is Evidence-based Make RA Simple Make RA Safe Ensure RA is Taught well Ensure Pts receive RA Fascial Plane Blocks have a role @amit_pawa

Concepts in Fascial Plane Blocks - What Every Anaesthetist Needs to Know

Concepts in Fascial Plane Blocks - What Every Anaesthetist Needs to Know

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Concepts in Fascial Plane Blocks - What Every Anaesthetist Needs to Know