Surgical Techniques in Moyamoya Vasculopathy E-Book

Peter Vajkoczy

• Herausgeber: Thieme
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 414

Veröffentlichungsjahr: 2019

Beschreibung

In rare cases of stroke in children and youths, a likely cause is the idiopathic disease moyamoya, characterized by the slow and progressive stenosis and occlusion of the internal carotid artery and the arteries of the circle of Willis. A result of these stenoses is the formation of collaterals that are typically small and fragile, and liable to rupture.

While there is no cure for moyamoya, a variety of surgical procedures can be performed to reestablish and maintain adequate blood supply to the affected brain areas. The procedures described here include various revascularization techniques and recommended bypasses.

Key Features:

• With contributions from the world's most renowned bypass surgeons
• Perioperative management and considerations
• An overall practical approach to this painstaking high-end surgery
• Detailed criteria for analyzing the situation and choosing the appropriate procedure
• General principles of bypass surgery, direct and indirect revascularization, and combined revascularization techniques
• Step-by-step descriptions of these procedures
• Rescue strategies when repeat surgery is necessary

Surgical Techniques in Moyamoya Vasculopathy is an indispensable guide for the experienced neurovascular surgeon.

This book includes complimentary access to a digital copy on https://medone.thieme.com.

Leseprobe

Surgical Techniques in Moyamoya Vasculopathy

Tricks of the Trade

Peter Vajkoczy, MDProfessorChairman, Department of Neurosurgery and Pediatric NeurosurgeryCharité Universitätsmedizin BerlinBerlin, Germany

471 illustrations

ThiemeStuttgart • New York • Delhi • Rio de Janeiro

Library of Congress Cataloging-in-Publication Data is available from the publisher

Illustrator: Lucius Fekonja, Berlin, Germany

© 2020. Thieme. All rights reserved.

Georg Thieme Verlag KGRüdigerstrasse 14, 70469 Stuttgart, Germany+49 [0]711 8931 421, [email protected]

Thieme Publishers New York333 Seventh Avenue, New York, NY 10001 USA+1 800 782 3488, [email protected]

Thieme Publishers DelhiA-12, Second Floor, Sector-2, Noida-201301Uttar Pradesh, India+91 120 45 566 00, [email protected]

Thieme Publishers Rio de Janeiro,Thieme Publicações Ltda.Edifício Rodolpho de Paoli, 25· andarAv. Nilo Peçanha, 50 – Sala 2508Rio de Janeiro 20020-906 Brasil+55 21 3172 2297

Cover design: Thieme Publishing GroupCover illustration: Lucius Fekonja, Berlin, GermanyTypesetting by Thomson Digital, India

Printed in Germany by CPI Books            5 4 3 2 1

ISBN 978-3-13-145061-6

Also available as an e-book:eISBN 978-3-13-147081-2

Important note: Medicine is an ever-changing science undergoing continual development. Research and clinical experience are continually expanding our knowledge, in particular our knowledge of proper treatment and drug therapy. Insofar as this book mentions any dosage or application, readers may rest assured that the authors, editors, and publishers have made every effort to ensure that such references are in accordance with the state of knowledge at the time of production of the book.

Nevertheless, this does not involve, imply, or express any guarantee or responsibility on the part of the publishers in respect to any dosage instructions and forms of applications stated in the book. Every user is requested to examine carefully the manufacturers’ leaflets accompanying each drug and to check, if necessary in consultation with a physician or specialist, whether the dosage schedules mentioned therein or the contraindications stated by the manufacturers differ from the statements made in the present book. Such examination is particularly important with drugs that are either rarely used or have been newly released on the market. Every dosage schedule or every form of application used is entirely at the user’s own risk and responsibility. The authors and publishers request every user to report to the publishers any discrepancies or inaccuracies noticed. If errors in this work are found after publication, errata will be posted at www.thieme.com on the product description page.

Some of the product names, patents, and registered designs referred to in this book are in fact registered trademarks or proprietary names even though specific reference to this fact is not always made in the text. Therefore, the appearance of a name without designation as proprietary is not to be construed as a representation by the publisher that it is in the public domain.

This book, including all parts thereof, is legally protected by copyright. Any use, exploitation, or commercialization outside the narrow limits set by copyright legislation without the publisher’s consent is illegal and liable to prosecution. This applies in particular to photostat reproduction, copying, mimeographing or duplication of any kind, translating, preparation of microfilms, and electronic data processing and storage.

Contents

Foreword

Preface

Contributors

Part 1General Concepts

1 Perioperative Management and Considerations

Bettina Föhre and Susanne König

1.1 Physiology

1.1.1 Basic Physiology of Cerebral Blood Flow

1.1.2 What Is Different in Patients with Moyamoya Disease?

1.2 Anesthesia

1.2.1 Choice of Anesthesia Technique

1.2.2 Preoperative Evaluation and Premedication

1.2.3 Monitoring

1.2.4 Targets of Anesthesia

1.2.5 Induction and Maintenance

1.2.6 Emergence

1.3 Postoperative Care for Moyamoya Disease Patients

1.3.1 Where?

1.3.2 Pain Control

1.4 Threats of Anesthesia for Moyamoya Disease Surgery

1.4.1 Ischemic Stroke and Transient Ischemic Attacks

1.4.2 Cerebral Hyperperfusion Syndrome

References

Suggested Readings

2 General Principles of Direct Bypass Surgery

Marcus Czabanka and Peter Vajkoczy

2.1 History and Initial Description

2.2 Analysis of Hemodynamic Compromise for Direct Bypass Surgery

2.3 Key Principles of Direct Revascularization Surgery

2.3.1 Graft Choice

2.3.2 Recipient Artery

2.3.3 Standardized Strategies versus Targeted Bypass Procedures

2.3.4 Peri- and Intraoperative Management and Neuroprotection

2.3.5 Intraoperative Flow Assessment

2.4 General Complications and Risk Stratification

References

3 General Principles of Indirect Bypass Surgery

Satoshi Kuroda

3.1 Introduction

3.2 History and Initial Description

3.3 Pathophysiology

3.4 Concept of Indirect Bypass Surgery

References

Part 2Indirect Revascularization

4 Multiple Burr Holes

Thomas Blauwblomme, Philippe Meyer, and Christian Sainte-Rose

4.1 History and Initial Description

4.2 Indications

4.3 Key Principles

4.4 SWOT Analysis

4.4.1 Strengths

4.4.2 Weakness

4.4.3 Opportunities

4.4.4 Threats

4.5 Contraindications

4.6 Special Considerations

4.6.1 Imaging

4.6.2 Patient

4.7 Pitfalls, Risk Assessment, and Complications

4.8 Special Instructions, Position, and Anesthesia

4.8.1 Anesthesia

4.8.2 Position

4.9 Skin Incision and Key Surgical Steps

4.10 Difficulties Encountered

4.11 Bailout, Rescue, and Salvage Maneuvers

4.12 Tips, Pearls, and Lessons Learned

References

5 Encephalo-myo-synangiosis

Nils Hecht and Peter Vajkoczy

5.1 History and Initial Description

5.2 Indications

5.3 Key Principles

5.4 SWOT Analysis

5.4.1 Strengths

5.4.2 Weaknesses

5.4.3 Opportunities

5.4.4 Threats

5.5 Contraindications

5.6 Special Considerations

5.7 Pitfalls, Risk Assessment, and Complications

5.8 Special Instructions, Position, and Anesthesia

5.9 Key Surgical Steps

5.9.1 Patient Position and Skin Incision

5.9.2 Pterional Skin Incision

5.9.3 Separate Skin and Muscle Flaps

5.9.4 Mobilization of the Temporalis Muscle

5.9.5 Elevation of the Muscle Flap

5.9.6 Craniotomy and Drilling of the Sphenoid Wing

5.9.7 Opening of the Dura and Encephaloduro-synangiosis

5.9.8 Suturing of the Muscle Fascia to the Edge of the Dural Opening

5.9.9 Bone Flap Reimplantation

5.10 Difficulties Encountered

5.11 Bailout, Rescue, and Salvage Maneuvers

5.12 Tips, Pearls, and Lessons Learned

References

6 Encephalo-duro-arterio-synangiosis: Pediatric

Edward Smith

6.1 History and Initial Description

6.2 Indications

6.3 Key Principles

6.4 SWOT Analysis

6.4.1 Strengths

6.4.2 Weaknesses

6.4.3 Opportunities

6.4.4 Threats

6.5 Contraindications

6.5.1 General Contraindications to Revascularization Surgery

6.5.2 Specific Contraindications to EDAS

6.6 Special Considerations

6.7 Pitfalls, Risk Assessment, and Complications

6.8 Special Instructions, Position, and Anesthesia

6.9 Patient Position with Skin Incision and Key Surgical Steps

6.10 Difficulties Encountered

6.11 Bailout, Rescue, and Salvage Maneuvers

6.12 Tips, Pearls, and Lessons Learned

Suggested Readings

7 Encephalo-duro-arterio-synangiosis: In Adults

Hao Jiang, Michael Schiraldi, and Nestor R. Gonzalez

7.1 History and Initial Description

7.1.1 Literature Support for the Use of EDAS in Adults

7.2 Indications

7.3 Key Principles for the EDAS Surgery in Adults

7.4 SWOT Analysis

7.4.1 Strengths

7.4.2 Weaknesses

7.4.3 Opportunities

7.4.4 Threats

7.5 Specific Adult EDAS Contraindications

7.5.1 Absolute

7.5.2 Relative

7.5.3 Not Contraindications

7.6 Special Considerations

7.6.1 Care Beyond the Surgical Field

7.7 Risk Assessment and Complications

7.8 Preoperative Workup

7.8.1 Specific Consideration with Anticoagulation

7.9 Patient Preparation

7.9.1 Patient Position with Skin Incision

7.10 Surgical Steps

7.10.1 STA Dissection

7.10.2 STA Care and Preservation

7.10.3 Craniotomy

7.10.4 Middle Meningeal Artery Preservation

7.10.5 Cerebrospinal Fluid Release

7.10.6 Dural Flaps Preparation and Superficial Temporal Artery Fixation

7.10.7 Craniotomy Closure

7.11 Difficulties Encountered and Pearls of Management

7.12 Pitfalls

7.13 Bailout, Rescue, and Salvage Maneuvers

7.14 Postoperative Care

7.14.1 Patient Surveillance

7.14.2 EDAS Functional Assessment

7.14.3 EDAS Angiographic Assessment

7.14.4 Advanced Imaging

References

8 Bifrontal Encephalo-duro-periosteal-synangiosis Combined with STA–MCA Bypass

Giuseppe Esposito, Annick Kronenburg, Jorn Fierstra, Kees P.J. Braun, Catharina J.M. Klijn, Albert van der Zwan, and Luca Regli

8.1 History and Initial Description

8.2 Indications

8.3 Key Principles

8.4 SWOT Analysis

8.5 Contraindications

8.6 Special Considerations

8.7 Complications

8.8 Special Instructions and Anesthesia

8.9 Patient Position with Skin Incision and Key Surgical Steps

8.9.1 Direct (STA–MCA) and Indirect (EDMS) Bypass for Unilateral MCA Territory Revascularization

8.9.2 Bifrontal EDPS

8.10 Difficulties Encountered

8.11 Bailout, Rescue, and Salvage Manoeuvres

8.12 Tips, Pearls, and Lessons Learned

References

Part 3Direct Revascularization

9 STA–MCA Bypass for Direct Revascularization in Moyamoya Disease

Alessandro Narducci and Peter Vajkoczy

9.1 History and Initial Description

9.2 Indications

9.3 Key Principles

9.4 SWOT Analysis

9.4.1 Strengths

9.4.2 Weaknesses

9.4.3 Opportunities

9.4.4 Threats

9.5 Contraindications

9.6 Special Considerations

9.6.1 Preoperative Imaging

9.6.2 Anticoagulation

9.6.3 Other Considerations

9.7 Pitfalls, Risk Assessment, and Complications

9.8 Special Instructions, Position, and Anesthesia

9.9 Patient Position with Skin Incision and Key Surgical Steps

9.9.1 Preparation

9.9.2 Surgical Technique

9.10 Difficulties Encountered

9.11 Bailout, Rescue, and Salvage Maneuvers

9.12 Tips, Pearls, and Lessons Learned

9.12.1 Preoperative Evaluations

9.12.2 Technical Tips

9.12.3 Postoperative Care

References

10 Double-Barrel Bypass in Moyamoya Disease

John E. Wanebo and Robert F. Spetzler

10.1 History and Initial Description

10.2 Indications

10.3 Key Principles of the Double-Barrel Bypass

10.4 SWOT Analysis

10.4.1 Strengths

10.4.2 Weaknesses

10.4.3 Opportunity

10.4.4 Threats

10.5 Contraindications

10.6 Special Considerations

10.7 Risk Assessment and Complications

10.8 Special Instructions, Position, and Anesthesia

10.8.1 Preoperative Workup

10.8.2 Patient Position

10.8.3 Anesthesia

10.9 Skin Incision and Key Surgical Steps

10.9.1 Skin Incision and Dissection of STA

10.9.2 Temporal Muscle Dissection and Craniotomy

10.9.3 Dural Opening

10.9.4 Anastomotic Site Selection

10.9.5 Donor STA Preparation

10.9.6 Recipient MCA Branch Preparation

10.9.7 MCA Arteriotomy

10.9.8 Anastomosis

10.9.9 Graded Release of the Temporary Clips and Hemostasis

10.9.10 Second Anastomoses

10.9.11 Closure Phase

10.9.12 Postoperative Care

10.10 Difficulties Encountered

10.11 Bailout, Rescue, and Salvage Maneuvers

10.12 Tips, Pearls, and Lessons Learned

References

11 Occipital Artery–Middle Cerebral Artery Bypass in Moyamoya Disease

Ken Kazumata

11.1 History and Initial Description

11.2 Indications

11.3 Key Principles

11.4 SWOT Analysis

11.4.1 Strengths

11.4.2 Weaknesses

11.4.3 Opportunities

11.4.4 Threats

11.5 Contraindications

11.6 Special Considerations

11.7 Pitfalls, Risk Assessment, and Complications

11.8 Special Instructions, Position, and Anesthesia

11.9 Patient Position with Skin Incision and Key Surgical Steps

11.10 Difficulties Encountered

11.11 Bailout, Rescue, and Salvage Maneuvers

11.12 Tips, Pearls, and Lessons Learned

References

12 STA–ACA/MCA Double Bypasses with Long Grafts

Akitsugu Kawashima

12.1 History and Initial Description

12.2 Indications

12.3 Key Principle of STA–ACA/MCA Double Bypasses with Long Grafts

12.4 SWOT Analysis

12.4.1 Strength

12.4.2 Weaknesses

12.4.3 Opportunity

12.4.4 Threats

12.5 Contraindications

12.6 Special Considerations

12.7 Pitfalls, Risk Assessment, and Complications

12.8 Special Instructions, Position, and Anesthesia

12.9 Patient Position with Skin Incision and Key Surgical Steps

12.10 Difficulties Encountered

12.11 Bailout, Rescue, and Salvage Maneuvers

12.12 Tips, Pearls, and Lessons Learned

12.12.1 Graft Management

12.12.2 Anastomosis

12.12.3 Training

Suggested Readings

13 Double Anastomosis Using Only One Branch of the Superficial Temporal Artery: Single-Vessel Double Anastomosis

Ziad A. Hage, Gregory D. Arnone, and Fady T. Charbel

13.1 History and Initial Description

13.2 Indications

13.3 Key Principles

13.4 SWOT Analysis

13.4.1 Strengths

13.4.2 Weaknesses

13.4.3 Opportunities

13.4.4 Threats

13.5 Contraindications

13.6 Special Considerations

13.7 Pitfalls, Risk Assessment, and Complications

13.8 Special Instructions, Position, and Anesthesia

13.9 Skin Incision and Key Surgical Steps

13.10 Difficulties Encountered

13.11 Bailout, Rescue, and Salvage Maneuvers

13.12 Tips, Pearls, and Lessons Learned

References

Suggested Readings

Part 4Combined Revascularization

14 Combined STA–MCA Bypass and Encephalo-myo-synangiosis

Marcus Czabanka and Peter Vajkoczy

14.1 History and Initial Description

14.2 Indications

14.3 Key Principles

14.4 SWOT Analysis

14.4.1 Strengths

14.4.2 Weaknesses

14.4.3 Opportunities

14.4.4 Threats

14.5 Contraindications

14.6 Special Considerations

14.7 Pitfalls, Risk Assessment, and Complications

14.8 Special Instructions, Position, and Anesthesia

14.9 Patient Position and Key Surgical Steps 97

14.10 Difficulties Encountered

14.11 Bailout, Rescue, and Salvage Maneuvers

14.12 Tips, Pearls, and Lessons learned

References

15 STA–MCA Bypass and EMS/EDMS

Ken Kazumata and Kiyohiro Houkin

15.1 History and Initial Description

15.2 Indications

15.3 Key Principles

15.4 SWOT Analysis

15.4.1 Strengths

15.4.2 Weaknesses

15.4.3 Opportunities

15.4.4 Threats

15.5 Contraindications

15.6 Special Considerations

15.7 Pitfalls, Risk Assessment, and Complications

15.8 Special Instructions, Position, and Anesthesia

15.9 Patient Position with Skin Incision and Key Surgical Steps

15.10 Difficulties Encountered

15.11 Bailout, Rescue, and Salvage Maneuvers

15.12 Tips, Pearls, and Lessons Learned

References

16 Combined Direct (STA–MCA) and Indirect (EDAS) EC–IC Bypass

Erez Nossek, Annick Kronenburg, and David J. Langer

16.1 History and Initial Description

16.2 Indications

16.3 Key Principles

16.4 SWOT Analysis

16.5 Contraindications

16.6 Special Considerations

16.6.1 Preoperative Considerations

16.6.2 Postoperative Considerations

16.7 Pitfalls, Risk Assessment, and Complications

16.8 Special Instructions, Position, and Anesthesia

16.9 Patient Position with Skin Incision and Key Surgical Steps

16.9.1 Description of the Technique

16.10 Difficulties Encountered

16.11 Bailout, Rescue, and Salvage Maneuvers

16.12 Tips, Pearls, and Lessons Learned

References

17 STA–MCA Anastomosis and EDMAPS

Satoshi Kuroda

17.1 History and Initial Description

17.1.1 STA–MCA Anastomosis and EDMAPS as an “Ultimate” Bypass

17.2 Indications and Contraindications

17.2.1 Asymptomatic Moyamoya Disease

17.2.2 Ischemic-Tpe Moyamoya Disease

17.2.3 Hemorrhagic-Type Moyamoya Disease

17.3 Key Principles

17.4 SWOT Analysis

17.5 Special Considerations

17.6 Pitfalls, Risk Assessment, and Complications

17.7 Special Instructions and Anesthesia

17.8 Patient Position with Skin Incision and Key Surgical Steps

17.8.1 Skin Incision and Donor Tissue Preparation

17.8.2 Craniotomy and Dural Opening

17.8.3 Direct STA–MCA Anastomosis

17.8.4 Indirect Bypass and Cranioplasty

17.9 Difficulties Encountered

17.9.1 Preservation of Scalp Blood Flow

17.9.2 Preservation of the MMA during Craniotomy

17.9.3 ICG Videoangiography before Craniotomy 124

17.9.4 STA–MCA Anastomosis

17.10 Bailout, Rescue, and Salvage Maneuvers

References

18 STA–MCA Bypass and Encephaloduro-arterio-synangiosis

Sepideh Amin-Hanjani

18.1 History and Initial Description

18.2 Indications

18.3 Key Principles

18.4 SWOT Analysis

18.4.1 Strengths

18.4.2 Weaknesses

18.4.3 Opportunity

18.4.4 Threat

18.5 Contraindications

18.6 Special Considerations

18.7 Pitfalls, Risk Assessment, and Complications

18.8 Special Instructions, Position, and Anesthesia

18.9 Patient Position with Skin Incision and Key Surgical Steps

18.9.1 Position

18.9.2 Skin Incision and STA Harvest

18.9.3 Craniotomy

18.9.4 Recipient Vessel Preparation

18.9.5 Donor Vessel Preparation

18.9.6 STA–MCA Bypass

18.9.7 Encephalo-arterio-synangiosis

18.9.8 Encephaloduro-synangiosis

18.9.9 Closure

18.10 Difficulties Encountered

18.10.1 Donor Vessel

18.10.2 Craniotomy/Durotomy

18.10.3 Recipient Vessel

18.10.4 Anastomosis

18.10.5 Closure

18.11 Bailout, Rescue, and Salvage Maneuvers

18.12 Tips, Pearls, and Lessons Learned

18.12.1 Preoperative Management

18.12.2 Intraoperative Anesthetic Management

18.12.3 Intraoperative Technique

References

19 Individualized Extracranial-Intracranial Revascularization in the Treatment of Late-Stage Moyamoya Disease

Bin Xu

19.1 History and Initial Description

19.2 Indications

19.3 Key Principles

19.4 SWOT Analysis

19.4.1 Strength

19.4.2 Weaknesses

19.4.3 Opportunities

19.4.4 Threats

19.5 Contraindications

19.6 Special Considerations

19.7 Pitfalls, Risk Assessment, and Complications

19.8 Special Instructions, Position, and Anesthesia

19.9 Patient Position with Skin Incision and Key Surgical Steps

19.9.1 Skin Incision

19.9.2 Temporal Muscle

19.9.3 Bone Flap

19.9.4 Dura Mater

19.9.5 Target Revascularization

19.9.6 The Simplest Anastomosis Techniques

19.10 Difficulties Encountered

19.11 Bailout, Rescue, and Salvage Maneuvers

19.12 Tips, Pearls, and Lessons Learned

Suggested Readings

Part 5Rescue Strategies for Repeat Surgery

20 Omental–Cranial Transposition

Mario Teo, Jeremiah N. Johnson, and Gary K. Steinberg

20.1 Background

20.1.1 History

20.2 Indications

20.3 Key Principles

20.4 SWOT Analysis

20.4.1 Strength

20.4.2 Weakness

20.4.3 Opportunity

20.4.4 Threat

20.5 Contraindications

20.6 Special Considerations

20.7 Risk Assessment: Our Experience

20.8 Preoperative Workup

20.8.1 Specific Consideration with Anticoagulation

20.9 Patient Preparation

20.9.1 Patient Position with Skin Incision

20.10 Surgical Steps

20.10.1 Key Procedural Step 1: Omental Harvest

20.10.2 Key Procedural Step 2: Delivery and Tunneling

20.10.3 Key Procedural Step 3: Craniotomy

20.11 Tips, Pearls, and Lessons Learned

20.12 Pitfalls

20.13 Bailout, Rescue, and Salvage Maneuvers

20.14 Postoperative Care

20.14.1 Patient Surveillance

20.14.2 Bypass Function Assessment

20.15 Case Illustrations

20.15.1 Case 1

20.15.2 Case 2

20.16 Conclusion

Suggested Readings

21 ECA–MCA Bypass with Radial Artery Graft

Satoshi Hori and Peter Vajkoczy

21.1 History and Initial Description

21.2 Indications

21.3 Key Principles

21.4 SWOT Analysis

21.4.1 Strength

21.4.2 Weaknesses

21.4.3 Opportunity

21.4.4 Threat

21.5 Contraindications

21.6 Special Considerations

21.7 Pitfalls, Risk Assessment, and Complications

21.8 Special Instructions, Position, and Anesthesia

21.9 Patient Position with Skin Incision and Key Surgical Steps

21.10 Difficulties Encountered

21.11 Bailout, Rescue, and Salvage Maneuvers

21.12 Tips, Pearls, and Lessons Learned

References

22 OA–MCA or OA–PCA Bypass

Mario Teo, Jeremiah N. Johnson, and Gary K. Steinberg

22.1 Background

22.1.1 History

22.2 Indication

22.3 Key Principles

22.4 SWOT Analysis

22.4.1 Strength

22.4.2 Weakness

22.4.3 Opportunity

22.4.4 Threat

22.5 Contraindications

22.5.1 Relative Contraindications

22.6 Special Considerations

22.7 Risk Assessment—Stanford Experience

22.8 Preoperative Workup

22.8.1 Specific Consideration with Anticoagulation

22.9 Patient Preparation

22.9.1 Patient Position with Skin Incision

22.10 Surgical Steps

22.10.1 Key Procedural Step 1: OA Harvest

22.10.2 Key Procedural Step 2: Craniotomy and Dural Opening

22.10.3 Key Procedural Step 3: Prepare Recipient Vessel

22.10.4 Key Procedural Step 4: Prepare Donor Vessel

22.10.5 Key Procedural Step 5: Microanastomosis

22.10.6 Key Procedural Step 6: Ensure Bypass Graft Patency

22.10.7 Key Procedural Step 7: Closure

22.11 Tips, Pearls, and Lessons Learned

22.12 Pitfalls

22.13 Bailout, Rescue, and Salvage Maneuvers

22.14 Postoperative Care

22.14.1 Patient Surveillance

22.14.2 Bypass Function Assessment

22.15 Case Illustrations

22.15.1 Case 1: OA–PCA Bypass

22.15.2 Case 2: OA–MCA Bypass

22.16 Conclusion

Suggested Readings

23 PAA–MCA Bypass

Menno R. Germans and Luca Regli

23.1 History and Initial Description

23.2 Indications

23.3 Key Principles

23.4 SWOT Analysis

23.4.1 Strengths

23.4.2 Weakness

23.4.3 Opportunity

23.4.4 Threat

23.5 Contraindications

23.6 Special Considerations

23.7 Pitfalls, Risk Assessment, and Complications

23.8 Special Instructions, Position, and Anesthesia

23.9 Patient Position with Skin Incision and Key Surgical Steps

23.10 Difficulties Encountered

23.11 Bailout, Rescue, and Salvage Maneuvers

23.12 Tips, Pearls, and Lessons Learned

References

Index

Foreword

I have to admit that during the course of my professional career, I have not encountered anything as fascinating as moyamoya disease (MMD). I can still remember those days when MMD was considered a rare disease, mostly seen in patients from Japan, where it was originally described more than 50 years ago. It was fascinating to see the unusual cerebral angiograms of these patients, showing steno- occlusive changes to the brain-supplying arteries in combination with numerous newly formed small collateral channels at the base of the brain. These changes were difficult to comprehend, particularly when compared with vascular changes noticed in common cerebral ischemia. When it came to treating these patients, we had the option of choosing from a variety of procedures, again mostly introduced by our colleagues from Japan. These procedures were later on summarized under the broad category of “indirect cerebral revascularization.” Moreover, it was found more difficult from a technical point of view to perform an extraintracranial arterial bypass using the superficial temporal artery as the donor vessel. This was, however, not because the epicerebral recipient vessels were smaller in diameter in comparison to the situation in chronic cerebral ischemia. It was discovered later on that the cortical arteries in patients with MMD have a different morphologic design, with a thinner structure of the arterial wall, which in turn requires increased attention and a greater amount of skills when performing a direct end-to-side anastomosis.

Initially, we came across these patients only rarely, maybe two or three cases per year. But this has changed drastically over the years. At the end of my career, the number of patients with MMD had increased to about 30 to 40 per year, and it was no longer a local phenomenon. Meanwhile, sizable clinical series of patients with MMD have been published from centers all over the world.

So, what do we know now about MMD that we did not know 25 years ago? The lessons from clinical experience and related research data have further substantiated that MMD is a particular form of ischemic cerebral disease that can be differentiated from more common entities of cerebrovascular occlusive disease beyond characteristic angiographic findings. Based on functional studies, we now know that MMD is representative of hemodynamic cerebrovascular insufficiency. A further distinctive feature of MMD is the unique capability of the brain to create new collateral inflow channels to compensate for the impaired blood flow due to the underlying stenoocclusive process within the basal arteries. This is clearly illustrated in patients with advanced MMD, where angiographic findings demonstrate arterial collaterals from meningeal and even extracranial arteries, which is never observed in common cerebrovascular diseases. Considering this observation, surgical revascularization is the logical treatment of choice in patients with MMD.

In fact, it can be viewed as an enhancement of an underlying and ongoing natural process. Even in the absence of randomized clinical trials, it is now generally accepted that surgical revascularization is the only effective treatment for patients with MMD. This is further supported by clinical information derived from large postoperative follow-up studies.

It should be mentioned that this is good news for the field of vascular neurosurgery in general. It was not long ago that in the larger context of vascular neurosurgery, MMD was only mentioned under the heading “miscellaneous.” The situation is significantly different now; with extraintracranial bypass surgery for cerebral ischemia becoming obsolete, patients with cerebral aneurysms are increasingly being treated by interventional means, and patients with cerebral AV malformations are being referred to stereotactic radiosurgery. In view of these developments, it is difficult to provide a young colleague with an interest in vascular neurosurgery with good advice on what to do in the future, and I am happy that I do not have to answer this question for myself. However, I'm convinced that the management of patients with MMD will become more important in the future, especially in view of the fact that this disease is still underdiagnosed. It is also good to know that each patient with MMD is usually a candidate for two surgical procedures. There is obviously great potential for further research activities in relation to MMD.

This would not only include research on epidemiology and genetics of MMD but also on its pathophysiology, based on contemporary techniques of molecular biology and other techniques that have become available more recently. We require further information on questions such as what is the optimal surgical technique, if there is one, and if we should use different surgical approaches for pediatric and adult patients with MMD.

We also need more long-term follow-up studies involving our operated patients, and I am quite sure that there will be more surprises.

Finally, coming back to my personal fascination with MMD that I mentioned in the beginning, let me give you another example for purposes of illustration.

I found it most intriguing to study postoperative angiograms in patients who underwent a combined revascularization procedure 1 or 2 years earlier.

It was amazing to see the number and size of the muscular arterial branches that had ingrown and found connection with the cortical arterial network!

Sometimes, it is difficult to differentiate these newly formed muscular branches from the original extraintracranial arterial bypass. This is another unique feature of MMD, and one wonders if the identification of this mechanism or the isolation of the factor that enables this ingrowth of vessels intothe brain could be used for the treatment of other ischemic brain conditions as well.

I am grateful that my long-term coworker Peter Vajkoczy has obviously inherited this interest in MMD, and I will follow his future work with great interest.

Peter Schmiedek, MDEmeritus Professor of NeurosurgeryMannheim, Germany

Preface

Moyamoya vasculopathy (MMV) is a rare cerebrovascular disease that is characterized by bilateral progressive steno-occlusion of basal cerebral arteries, with the emergence of coexisting abnormal net-like vessels. In moyamoya disease, MMV is the single manifestation, whereas in moyamoya syndrome or quasi-moyamoya, MMV is associated with a potentially underlying disease such as a genetic disorder or other coexisting pathology. Although MMV is most frequent in Asian countries, it is ranked among the most frequent causes of stroke in children and adults across the world. The incidence of MMV is on the rise due to increasing awareness of the disease.

The relevance of surgical treatment of moyamoya disease by way of bypass revascularization is undisputed, which is in contrast to the surgical treatment of atherosclerotic carotid artery occlusion. The main aims of revascularization are to restore the blood supply to stabilize cerebrovascular hemodynamics and to regress the fragile moyamoya vessels in order to prevent bleeding. A successful improvement or normalization of cerebral hemodynamics will then result in secondary stroke prevention and improved neurological or neurocognitive outcome. Consequently, bypass surgery for MMV has become an integral part of the clinical practice of many microvascular neurosurgeons around the world. While the role of bypass surgery is well accepted, a versatile range of surgical techniques and strategies exists in the field, which makes it difficult to determine and appreciate the subtle nuances of the varied surgical strategies.

Therefore, it seemed logical to create an instructive manual for neurosurgeons with a step-by-step guide to the surgical techniques. The focus of this book is on introducing neurosurgeons (and other physicians involved in the treatment of these patients) to the different surgical techniques, to the inherent strengths and weaknesses of each technique, and to the surgical considerations that need to be kept in mind. We are grateful to the contributing authors, who are all authorities in their respective fields, for sharing their unique knowledge and expertise with the readers. The descriptions provided by each of them are characterized by an expert assessment of the distinct surgical techniques and their variations, as well as by a standardized illustration of the surgical steps. This book will thus serve as the key manual for everyone interested in the treatment of these complexities and for those who find it a rewarding experience to treat these patients.

Peter Vajkoczy, MD

Contributors

Sepideh Amin-Hanjani, MD

Department of Neurosurgery

University of Illinois at Chicago

Chicago, Illinois, USA

Gregory D. Arnone, MD

Department of Neurosurgery

Penn State College of Medicine

Hershey, Pennsylvania, USA

Thomas Blauwblomme, MD

Department of Pediatric Neurosurgery

Hospital Necker

Assistance Publique Hôpitaux de Paris (APHP)

Université René Descartes, PRES Sorbonne Paris Cité

Paris, France

Kees P.J. Braun, MD

Department of Neurology and Neurosurgery

UMC Utrecht Brain Center

Utrecht, The Netherlands

Fady T. Charbel, MD, FAANS, FACS

Professor and Head, Department of Neurosurgery

Richard L. and Gertrude W. Fruin Professor

University of Illinois at Chicago

Chicago, Illinois, USA

Marcus Czabanka, MD

Professor and Vice Chairman

Department of Neurosurgery

Charité Universitätsmedizin Berlin

Berlin, Germany

Giuseppe Esposito, MD, PhD

Neurosurgeon, Senior Physician

Department of Neurosurgery

Clinical Neurocenter

University Hospital Zurich

University of Zurich

Zurich, Switzerland

Jorn Fierstra, MD, PhD

Department of Neurosurgery

Clinical Neurocenter

University Hospital Zurich

University of Zurich

Zurich, Switzerland

Bettina Föhre, MD

Consultant of Anesthesiology

Department of Anesthesiology and Operative Intensive Care Medicine (CCM/CVK)

Charité Universitätsmedizin Berlin

Berlin, Germany

Menno R. Germans, MD

Neurosurgeon

Department of Neurosurgery

University Hospital Zurich

Zurich, Switzerland

Nestor R. Gonzalez, MD, MSCR, FAANS, FAHA

Professor of Neurosurgery

Director, Neurovascular Laboratory

Neuroendovascular Fellowship Program Director

Cedars-Sinai Medical Center

Advanced Health Sciences Pavilion (AHSP)

Los Angeles, California, USA

Ziad A. Hage, MD, FAANS

Novant Health Presbyterian Medical Center

Adjunct Associate Professor

Campbell University

School of Osteopathic Medicine

Charlotte, North Carolina, USA

Nils Hecht, MD

Department of Neurosurgery

Charité Universitätsmedizin Berlin

Berlin, Germany

Satoshi Hori, MD, PhD

Department of Neurosurgery

Graduate School of Medicine and Pharmacological Science

University of Toyama

Toyama, Japan

Kiyohiro Houkin, MD

Department of Neurosurgery

Faculty of Medicine

Hokkaido University

Sapporo, Japan

Hao Jiang, MD

Department of Neurosurgery

The First Affiliated Hospital

Zhejiang University School of Medicine

Hangzhou, China

Jeremiah N. Johnson, MD, FAANS

Assistant Professor

Department of Neurosurgery

Baylor College of Medicine

Houston, Texas USA

Akitsugu Kawashima, MD, PhD

Chief, Department of Neurosurgery

Tokyo Women’s Medical University Yachiyo Medical Center

Chiba, Japan

Ken Kazumata, MD, PhD

Department of Neurosurgery

Hokkaido University Graduate School of Medicine

Sapporo, Japan

Catharina J.M. Klijn, MD

Department of Neurology and Neurosurgery

UMC Utrecht Brain Center

Utrecht, The Netherlands

Department of Neurology

Donders Institute for Brain, Cognition and Behavior

Center for Neuroscience

Radboud University Medical Center

Nijmegen, The Netherlands

Susanne König, MD, DESA

Consultant of Anesthesiology

Department of Anesthesiology and Operative Intensive Care Medicine (CCM/CVK)

Charité Universitätsmedizin Berlin

Berlin, Germany

Annick Kronenburg, MD

Department of Neurology and Neurosurgery

UMC Utrecht Brain Center

Utrecht, The Netherlands

Satoshi Kuroda, MD, PhD

Professor and Chairman

Department of Neurosurgery

Graduate School of Medicine and Pharmaceutical Science

University of Toyama

Toyama, Japan

David J. Langer, MD

Department of Neurosurgery

Hofstra North Shore–Long Island Jewish School of Medicine

Lenox Hill Hospital

New York, New York, USA

Philippe Meyer, MD

Department of Pediatric Anesthesiology

Hospital Necker

Assistance Publique Hôpitaux de Paris (APHP)

Paris, France

Alessandro Narducci, MD

Division of Neurosurgery

San Giovanni Bosco Hospital

Turin, Italy

Erez Nossek, MD

Division of Neurosurgery

Maimonides Medical Center

Brooklyn, New York, USA

Luca Regli, MD

Professor and Chairman

Department of Neurosurgery

Clinical Neurocenter

University Hospital Zurich

University of Zurich

Zurich, Switzerland

Christian Sainte-Rose, MD

Department of Pediatric Neurosurgery

Hospital Necker

Assistance Publique Hôpitaux de Paris (APHP)

Université René Descartes, PRES Sorbonne Paris Cité

Paris, France

Michael Schiraldi, MD, PhD

Neurosurgeon

Institute of Clinical Orthopedics & Neurosciences

Desert Regional Medical Center

Palm Springs, California, USA

Edward Smith, MD

Department of Neurosurgery

Boston Children’s Hospital

Harvard Medical School

Boston, Massachusetts, USA

Robert F. Spetzler, MD

Department of Neurosurgery

Barrow Neurological Institute

St. Joseph’s Hospital and Medical Center

Phoenix, Arizona, USA

Gary K. Steinberg, MD, PhD

Bernard and Ronni Lacroute-William Randolph Hearst Professor of Neurosurgery and the Neurosciences

Chair, Department of Neurosurgery

Stanford University School of Medicine

Stanford, California, USA

Mario Teo, MBChB(Hons), FRCS(SN)

Consultant Neurosurgeon

Department of Neurosurgery

Bristol Institute of Clinical Neuroscience

North Bristol University Hospital

Bristol, UK

Peter Vajkoczy, MD

Professor

Chairman, Department of Neurosurgery and Pediatric Neurosurgery

Charité Universitätsmedizin Berlin

Berlin, Germany

John E. Wanebo, MD

Department of Neurosurgery

Barrow Neurological Institute

St. Joseph’s Hospital and Medical Center

Phoenix, Arizona, USA

Bin Xu, MD, PhD

Department of Neurosurgery, Huashan Hospital

Shanghai Medical School, Fudan University

Shanghai, China

Albert van der Zwan, MD

Department of Neurology and Neurosurgery

UMC Utrecht Brain Center

Utrecht, The Netherlands

Part 1

General Concepts

1 Perioperative Management and Considerations

2 General Principles of Direct Bypass Surgery

3 General Principles of Indirect Bypass Surgery

1 Perioperative Management and Considerations

Bettina Föhre and Susanne König

Abstract

Typically in patients with moyamoya disease (MMD), the cerebrovascular reactivity and the cerebral hemodynamic reserve capacity are impaired, causing transient ischemic attack (TIA) or stroke. Therefore the superior aim of anesthetic management for revascularization procedures is to ensure the adequate perfusion and oxygenation of the brain to avoid ischemic episodes.

Special attention is paid to maintain the systolic blood pressure between 120 and 140 mm Hg perioperatively, to avoid hypo- and hypertension and to ensure normoxemia, normocapnia, and normovolemia with crystalloids.

The two concepts of a propofol-based anesthesia and an inhalational anesthesia, either in combination with a short-acting analgesic agent, are both established for surgery in moyamoya patients. The authors favor the total intravenous anesthesia, because of the lower rate of postoperative nausea and vomiting and the better preservation of the regional cortical blood flow in the frontal lobe.

Postoperatively early extubation for an immediate neurological assessment is usually attempted. It demands adequate analgesia and often the use of alpha- or beta-blocking agents to ensure a smooth, stressless, and hemodynamically controlled awakening.

Keywords: impaired hemodynamic reserve capacity, ischemic episodes, normotension, normocapnia, total intravenous anesthesia, early neurological assessment

1.1 Physiology

1.1.1Basic Physiology of Cerebral Blood Flow

The normal cerebral blood flow (CBF) of 50 mL/100g/min-1 is dependent on cerebral perfusion pressure (CPP), i.e., the difference between mean arterial pressure and intracranial pressure (MAP − ICP).

Three main principles regulate CBF: (1) flow-metabolism coupling, (2) autoregulation, and (3) carbon dioxide (CO2) reactivity. In regions of increased metabolic activity the local CBF is increased by vasodilation of arterioles to deliver more oxygen and glucose, whereas vasoconstriction is encountered in phases of diminished activity.

In healthy adults, cerebral autoregulation keeps CBF constant within blood pressure ranges between 50 and 150 mm Hg, thus preventing cerebral ischemia. Cerebral vessels react to arterial partial pressure of carbon dioxide (PaCO2) by responding to hypercapnia with vasodilation and vice versa.

As described in the Monro-Kellie doctrine, the intracranial volume is the sum of brain tissue, intracranial blood volume, and cerebrospinal fluid and is limited by the non-expandable skull.

The ICP-volume curve is nonlinear and shows the relationship between intracranial volume and ICP. When the initial intracranial volume is low and compensatory mechanisms are not exhausted, an increase in intracranial volume produces a small change in ICP. On the steep part of the curve a similar increase of intracranial volume results in a large increase of ICP, resulting in a decrease of CPP, respectively CBF (▶ Fig. 1.1).

Fig. 1.1 Basic physiology of cerebral blood flow.

1.1.2What Is Different in Patients with Moyamoya Disease?

Moyamoya is characterized by chronic progressive stenotic to occlusive changes in the terminal parts of the intracranial internal carotid arteries including the proximal parts of anterior and middle cerebral arteries. A compensatory fine vascular network is developed. Classically, moyamoya disease (MMD) is present bilaterally, but may also develop unilaterally. In these compromised areas, the cerebrovascular reactivity and the cerebral hemodynamic reserve capacity are impaired, causing transient ischemic attacks (TIAs) or strokes. 1 The risk of impaired autoregulation may be even higher in pediatric patients. 2

Furthermore, the fragile moyamoya vessels are prone to hemorrhage. Typically, CBF shows a paradoxic reactivity to a vasodilatory stimulus in the altered areas. The altered moyamoya vessels are already maximally dilated to provide adequate oxygen supply and perfusion to the brain tissue. These vessels cannot react to a stimulus like hypercapnia the way normal vessels do. Thus, in a hypercapnic state flow will increase in brain areas of preserved normal vasculature and decrease in moyamoya affected vessels, leading to insufficient perfusion. This regional redistribution of blood flow to healthy areas is called “steal phenomenon” 3 and might clinically present as a neurologic deficit.

1.2 Anesthesia

1.2.1Choice of Anesthesia Technique

The superior aim of anesthesia for revascularization procedures is to ensure adequate perfusion and oxygenation of the brain and to avoid ischemic episodes. The ideal anesthetic agent should deliver smooth and hemodynamically stable anesthesia, good operating conditions (“slack brain”), and a smooth and rapid emergence to allow early neurological assessment. Cerebral perfusion pressure should be maintained, autoregulation and CO2 reactivity should be preserved.

There are some studies that have investigated propofol-maintained versus inhalational-maintained anesthesia in adult patients undergoing elective craniotomy. Both strategies were associated with similar brain relaxation, although mean ICP values were lower and CPP values higher with propofol-maintained anesthesia. The recovery profiles, e.g., eye opening, tracheal extubation, obeying verbal commands, and orientation varied only in the range of minutes without clinical significance. Also the incidence of postoperative pain, seizures, and agitation were similar with both techniques. Nevertheless, the incidence of postoperative nausea and vomiting (PONV) was significantly lower during propofol-maintained anesthesia. 4

Concerning moyamoya patients, both anesthetic concepts are established and no significant differences in patient outcome were noted. Rather the carefully titrated induction drugs and good control of blood pressure, oxygenation, and stability of CO2 level are determinative. 5

In authors’ opinion, there are some important arguments in favor of total intravenous anesthesia: the lower rate of PONV, 6 the better preservation of the regional cortical blood flow in the frontal lobe in comparison to sevoflurane, 7 the occurrence of steal phenomenon with inhalational anesthesia, 8 and finally, a positive practical experience with this technique for intracranial surgery over the past 20 years in their center.

1.2.2Preoperative Evaluation and Premedication

Patients with MMD often present with many other medical conditions, which may impact anesthetic management. Therefore, a profound preoperative anesthetic assessment is necessary and special attention should be paid to the preexisting neurologic deficits and the neurologic physical status. Motor deficits or epilepsy are signals of chronic ischemia. A history of frequent TIAs, prolonged intermittent neurologic deficits, or stroke should draw attention to an already impaired cerebral blood supply in these patients, and has been identified as a significant risk factor for perioperative complications. 9 Preoperative evaluation must also include the determination of the individual baseline blood pressure, which involves several measurements before the day of surgery. A comparative blood pressure measurement on both arms is recommended to exclude falsely low blood pressure measurement intraoperatively due to, for example, subclavian artery stenosis.

Hypertension is found in some patients as a compensatory mechanism for cerebral vascular insufficiency. Caution is necessary when attempting to treat an elevated blood pressure in these patients.

Special attention has to be paid to the patient’s chronic medication. Anticonvulsive and antihypertensive medication should be continued until the day of surgery.

Regarding the antiplatelet-medication in MMD patients, the practice of continuing the medication varies among centers. The perioperative application of aspirin and the postoperative antiplatelet therapy have become controversial. Some centers are giving antiplatelet-medication while others have abandoned them. In our center we determine the effectiveness of aspirin in each patient through a platelet-function test. Thereby detected aspirin nonresponders receive alternative antiplatelet agents. 10

Premedication should be prescribed carefully. Anxiolysis may be necessary and beneficial in children with MMD, as crying should be strictly avoided, because the resultant hyperventilation may lead to hypocapnia and consecutively to cerebral vasoconstriction, resulting in cerebral ischemia. Vice versa oversedation followed by hypoventilation should also be avoided.

Midazolam is most often used for premedication, but other drugs can also be used. 11

1.2.3Monitoring

The American Society of Anesthesiologists (ASA) standard monitoring should be extended to invasive arterial blood pressure monitoring and urine output measurement. Anesthesiologists should consider placing the arterial line prior to induction, especially if preexisting medical conditions prompt it, and if the procedure is not considered too stressful for the patient.

Continuous arterial blood pressure monitoring intra- and postoperatively is the key for keeping the blood pressure within a predefined range (see Chapter 1.2.4).

Adequate venous access is essential and can be established by two “well-running” intravenous lines. A central venous catheter is not mandatory but should be considered in patients with very poor venous access or severe coexisting medical conditions.

Cerebral function can be monitored in various ways. Most reliable techniques are the combined transcranial motor-evoked potentials (MEP) and sensory-evoked potentials (SEP) monitoring. Cerebral function monitoring is of crucial importance especially in pediatric patients and in unstable adult patients, because they may experience strokes even after short-term blood pressure drops. Electroencephalography can help identify focal slowing, indicating a compromise CBF. Although near-infrared spectroscopy (NIRS) is only validated for measurement of cerebral oxygen saturation on the forehead, it has been shown that a sustained drop in regional oxygen saturation is closely related to the occurrence of neurological events following surgery, 12 and thus NIRS may provide useful information intraoperatively.

1.2.4Targets of Anesthesia

Hemodynamics: What Is the Optimal Blood Pressure?

It is very important to have appropriate hemodynamic conditions throughout the perioperative period. Reduction in CBF is poorly tolerated, especially in children because they have a diminished autoregulatory response and a higher cerebral metabolic rate. 5

Hypotension may cause ischemia or threaten the graft patency because of developing thrombosis. Hypertension may lead to bleeding or cause a hyperperfusion syndrome with clinical symptoms such as an ischemic attack (see also ▶ Chapter 1.4.2).

There is not the one optimal blood pressure for all MMD patients. Generally it is recommended to maintain the blood pressure normotensive or to keep it within 10 to 20% of the preoperatively established baseline. 11,13 Some MMD patients induce hypertension and are dependent on higher systolic blood pressure levels. Therefore, the systolic blood pressure target should be determined for the individual MMD patient between the surgeon and the anesthesiologist. It is of tremendous importance to maintain the blood pressure stable perioperatively within the defined limits. According to our experience, in case of hypertensive adult MMD patients, we suggest to keep the systolic blood pressure 20% above the individual baseline systolic blood pressure. For normotensive adult patients, we suggest to keep the systolic blood pressure at 140 mm Hg. The individual baseline systolic blood pressure can function as the lower threshold for the systolic blood pressure.

Careful and smooth titration of anesthetic drugs for induction, maintenance of anesthesia as well as anticipating cardiovascular responses to surgical stimuli is very important for blood pressure control. Episodes of hypotension should be treated immediately with vasoactive drugs, e.g., norepinephrine or phenylephedrine.

The postoperative goal for blood pressure maintenance should be consented with the surgeon. The target blood pressure depends on the quality and diameter (which determines also the flow) of the bypass. It is also to be taken into consideration if additional indirect techniques have been performed, for example, encephalo-myo-synangiosis. Hyperperfusion of the brain has to be strictly avoided as well as insufficient flow and hypoperfusion. Thus, no general rule can be given. An appropriate analgesic management has to be established before emergence from anesthesia and during the postoperative period to prevent hypertensive episodes. Vasodilating drugs such as urapidil or labetalol should be kept handy.

 How to Ventilate the Patient?

Normocapnia should be the target of ventilation, regardless of the ventilator mode chosen. The arterial pCO2 should range between 39 and 43 mm Hg, because the cortical blood flow is maximal in this range. 14,15 A retrospective analysis of 124 children undergoing surgery for MMD showed that those patients who suffered from postoperative ischemic complications had intraoperatively PaCO2 levels significantly above 45 mm Hg. If additional risk factors (preoperative TIA) were present, the incidence of postoperative ischemic complications was even higher. 9 This is consistent with a recent investigation of adult MMD patients. It has been demonstrated that hemodynamically unstable Berlin Moyamoya Grade 3 patients (severe MMD) have the highest risk for perioperative ischemia. 16

The collateral network of vessels in patients with MMD is in a state of maximal vasodilation. When healthy vessels dilate in response to hypercapnia, they steal the blood from the hemodynamically compromised areas (of maximal vasodilation). 5,8 See Chapter 1.1.2.

1.2.5Induction and Maintenance

Induction

The major aim of anesthesia induction in MMD patients is to perform a smooth induction, not to allow blood pressure to swing between hypertension and hypotension, as well as to avoid hyperventilation, hypoventilation, and hypoxemia.

In children, it is recommended to carefully guide the separation from the parents before anesthesia to prevent crying and thus an increase of ICP or hyperventilation. Intubation should be performed in a deeply anesthetized patient to avoid any hemodynamic effect.

For intravenous induction the choice of agents includes propofol, thiopental, or etomidate.

Also in children, intravenous induction has some advantage over inhalational induction. For the latter, sevoflurane is the agent of choice. Intravenous opioids are recommended to attenuate the response to laryngoscopy and tracheal intubation. The authors prefer the short-acting remifentanil. Administration may be started at a low dose before the induction agent is applied (e.g., remifentanil 0.1 µg/kg BW/min for 5 minutes) and then continued and increased in dosage (e.g., 0.2–0.3 µg/kg BW/min) throughout the procedure as part of the total intravenous anesthesia (TIVA). Bolus administration of fentanyl (e.g., 3–3.5 µg/kg BW) for induction and repetitive doses throughout surgery is another option.

The ideal choice for muscle relaxation is a nondepolarizing agent, unlikely to cause hemodynamic changes or histamine release. 11,13,17

 Temperature

Body temperature should be monitored throughout the procedure and measures should be taken to maintain normal body temperature. The proposed beneficial effect of mild hypothermia reduces the cerebral metabolic rate and thus protects the brain against hypoxia and ischemia to some degree. However, as to date, no randomized controlled trial has been conducted to show the benefit of hypothermia for vascular patients in neurosurgery.

Moreover, hypothermia bears the risk of increased bleeding by compromising coagulation and may further precipitate postoperative shivering, and thus increase cerebral metabolic rate.

Indocyanine Green

Anesthesiologists might be asked to administer an intravenous bolus of indocyanine green (ICG) during bypass surgery. ICG video-angiography visualizes the patency of a bypass graft. Technically the angiography requires a microscope with an integrated ICG camera that applies near-infrared light on the surgical field.

ICG is delivered as a powder (25 mg) that has to be diluted in 5 cc of distilled water. Usually the applied dose ranges between 5 and 25 mg. Following the intravenous ICG injection, a short period of “falsely low” pulse oximetry values has to be anticipated due to the dye. ICG is administered in close communication with the surgeon either through a well running intravenous line or a central line, which is immediately flushed with a bolus of 20 cc sodium chloride.

ICG is generally a safe drug, nevertheless, cases have been reported of patients who showed adverse reaction to the ICG injection, especially hypotension. 18

 Volume Management

Perioperative fluid management should aim at maintaining normovolemia.

The holding of packed red blood cells or fresh frozen plasma for the surgical procedure should be agreed upon with the surgeon in each institution, depending on the average need for transfusion for the procedure. Intraoperatively, it is crucial to check hemoglobin and hematocrit values regularly. Severe anemia should be treated. There is no ideal hematocrit or hemoglobin level for all MMD patients, but polycythemia should be avoided as much as pronounced hemodilution, because both can lead to cerebral ischemia, the latter by reducing the oxygen-carrying capacity of the blood. 5,13

1.2.6Emergence

The major target at emergence is a smooth and hemodynamically controlled awakening. Extubation may be performed in the operating room (OR) if feasible, to allow for immediate neurological assessment. At the end of surgery an individual blood pressure range should be agreed upon between surgeon and anesthesiologist individualized for each patient, and any deviations should be treated immediately. Usually, the range for systolic blood pressure in adult patients will be set between 120 and 140 mm Hg. Blood pressure increases may occur during patient awakening and should be carefully treated with a well-controllable antihypertensive agent, e.g., with a beta-blocking agent (e.g., esmolol) or alpha-blocking agent urapidil (the latter is not available in United States and Canada). It is also crucial to prevent coughing or shivering and to administer sufficient pain relief.

Sufficient spontaneous ventilation will aid to maintain normocapnia, which should be regularly controlled via PaCO2 measurement through blood gas analysis. Adequate oxygen supply may be assured through oxygen insufflation via a nasal line. An oxygen mask should be avoided, since the straps put direct pressure on the side of the head where bypass surgery had just been performed.

1.3Postoperative Care for Moyamoya Disease Patients

1.3.1 Where?

Patients are transferred under continuous monitoring and care from the OR to an intensive care or postanesthesia care unit, where they are monitored overnight. Discharge to the normal ward should be decided the next morning, after neurologic examination and depending on the patient’s well-being.

Blood pressure, oxygen saturation, hematocrit, volume status, and urine output should be closely monitored in the postoperative period. Maintaining normovolemia and avoiding blood pressure exaggeration is crucial. Neurologic examination has to be performed frequently to identify ischemia at an early state. 13

1.3.2Pain Control

Good analgesia is an important factor in reducing the risk of postoperative cerebral ischemia or infarction. In children, pain relief can also help avoid crying and associated negative effects of hyperventilation and hypocapnia. Pain management can be performed according to the institution’s standards. Early after surgery, opioids will usually be part of the regimen. There are several options, e.g., piritramid (which is not approved in the United States), morphine, or fentanyl, which can be applied by titrating intravenous doses or by continuous infusion, the latter only if the patient is permanently monitored for signs of ventilatory suppression. Of note, when anesthesia was performed with a short-acting agent such as remifentanil, adequate additional analgesia, e.g., with an opioid such as morphine, has to be applied before emergence.

Additionally a peripherally acting analgesic should be applied before emergence, such as paracetamol or metamizol.

Placement of a skull block may be a useful addition to anesthesia in MMD patients. It has been shown to be helpful in children during encephalo-duro-arterio-myo synagiosis (EDAMS) surgery, providing calm awakening and lower analgesic requirements postoperatively. 19

1.4Threats of Anesthesia for Moyamoya Disease Surgery

Prevention of any deterioration of cerebral perfusion is pivotal in the care of MMD patients.

1.4.1Ischemic Stroke and Transient Ischemic Attacks

Transitory ischemic attacks can occur as a result of inappropriate cerebral perfusion and cannot be reliably detected while the patient is under anesthesia. Alternatively, a graft thrombosis may be the cause. As pointed out previously, hypotension or suboptimal blood pressure control has to be strictly avoided intra- and postoperatively. Generally, the controlled mild hypertension is of greatest relevance to prevent ischemic events in MMD patients. Clinicians should keep in mind the increased risk for ischemic complications in patients with a history of TIAs (see also Chapter 1.2.2). Patients undergoing indirect revascularization procedures will have a persistent risk for cerebral ischemia until the neovascularization has been completed, which may require months.

Intraoperatively bypass patency should be assessed directly and/or with ICG spectroscopy by the surgeon. Postoperatively, transcranial Doppler evaluation or perfusion CT/MRI are valuable diagnostic tools.

1.4.2Cerebral Hyperperfusion Syndrome

Typically in moyamoya patients the diseased vessels are already maximally vasodilated and show little autoregulatory capacity. The low-flow superficial temporal artery to middle cerebral artery (STA–MCA) bypass might lead to cerebral hyperperfusion in a previously poorly perfused cerebral vascular bed, often presenting as a transient neurological deterioration or an ischemic attack.

Furthermore, cerebral hyperperfusion may lead to intracranial hemorrhage with potentially fatal outcome, thus underlining the emphasis which has to be put onto a strict blood pressure control.

Key Points

Pathophysiologic considerations

Impaired autoregulation

Reduced cerebral hemodynamic reserve capacity

Steal phenomenon

Preoperative evaluation

Attention to previous transient ischemic attacks (TIAs), preexisting neurologic deficits

Stage of hemodynamic failure (see Chapter 1.2.2)

Concomitant disease

Antiplatelet and anticoagulation management of your center

Anesthetic goals

Adequate cerebral perfusion

Normotension, within 10–20% of baseline blood pressure

Normoxia, elevate fraction of inspired oxygen (FiO2) to 1.0 during temporary occlusion

Normocapnia

Normothermia

Normovolemia

Prefer propofol and a short-acting opioid

Sufficient analgesia intra- and postoperatively

Prevent hypo- and hypertension, hypo- and hypercapnia

Monitoring

Electrocardiogram, pulse oximetry, noninvasive blood pressure (BP)

Arterial line for invasive BP

Intravenous lines

Central venous catheter if required by concomitant disease

Urine output, body temperature

Near–infrared spectroscopy (NIRS)

Postoperative care

Transfer to intensive care unit

BP control within set limits

Ensure graft perfusion (antiplatelet or anticoagulation)

References

[1] Kuwabara Y, Ichiya Y, Sasaki M, et al. Response to hypercapnia in moyamoya disease. Cerebrovascular response to hypercapnia in pediatric and adult patients with moyamoya disease. Stroke. 1997; 28(4): 701‐707 PubMed

[2] Lee JK, Williams M, Jennings JM, et al. Cerebrovascular autoregulation in pediatric moyamoya disease. Paediatr Anaesth. 2013; 23(6): 547‐556 PubMed

[3] Han JS, Abou-Hamden A, Mandell DM, et al. Impact of extracranial-intracranial bypass on cerebrovascular reactivity and clinical outcome in patients with symptomatic moyamoya vasculopathy. Stroke. 2011; 42(11): 3047‐3054 PubMed

[4] Chui J, Mariappan R, Mehta J, Manninen P, Venkatraghavan L. Comparison of propofol and volatile agents for maintenance of anesthesia during elective craniotomy procedures: systematic review and meta-analysis. Can J Anaesth. 2014; 61(4): 347‐356 PubMed

[5] Chui J, Manninen P, Sacho RH, Venkatraghavan L. Anesthetic management of patients undergoing intracranial bypass procedures. Anesth Analg. 2015; 120(1): 193‐203 PubMed

[6] Sneyd JR, Andrews CJ, Tsubokawa T. Comparison of propofol/remifentanil and sevoflurane/remifentanil for maintenance of anaesthesia for elective intracranial surgery. Br J Anaesth. 2005; 94(6): 778‐783 PubMed

[7] Kikuta K, Takagi Y, Nozaki K, et al. Effects of intravenous anesthesia with propofol on regional cortical blood flow and intracranial pressure in surgery for moyamoya disease. Surg Neurol. 2007; 68(4): 421‐424 PubMed

[8] Sato K, Shirane R, Kato M, Yoshimoto T. Effect of inhalational anesthesia on cerebral circulation in Moyamoya disease. J Neurosurg Anesthesiol. 1999; 11(1): 25‐30 PubMed

[9] Iwama T, Hashimoto N, Yonekawa Y. The relevance of hemodynamic factors to perioperative ischemic complications in childhood moyamoya disease. Neurosurgery. 1996; 38(6): 1120‐1125, discussion 1125–1126 PubMed

[10] Smith ER, Scott RM. Surgical management of moyamoya syndrome. Skull Base. 2005; 15(1): 15‐26 PubMed

[11] Baykan N, Ozgen S, Ustalar ZS, Dagçinar A, Ozek MM. Moyamoya disease and anesthesia. Paediatr Anaesth. 2005; 15(12): 1111‐1115 PubMed

[12] Orihashi K, Sueda T, Okada K, Imai K. Near-infrared spectroscopy for monitoring cerebral ischemia during selective cerebral perfusion. Eur J Cardiothorac Surg. 2004; 26(5): 907‐911 PubMed

[13] Parray T, Martin TW, Siddiqui S. Moyamoya disease: a review of the disease and anesthetic management. J Neurosurg Anesthesiol. 2011; 23(2): 100‐109 PubMed

[14] Kurehara K, Ohnishi H, Touho H, Furuya H, Okuda T. Cortical blood flow response to hypercapnia during anaesthesia in Moyamoya disease. Can J Anaesth. 1993; 40(8): 709‐713 PubMed

[15] Yusa T, Yamashiro K. Local cortical cerebral blood flow and response to carbon dioxide during anesthesia in patients with moyamoya disease. J Anesth. 1999; 13(3): 131‐135 PubMed

[16]  Czabanka M, Boschi A, Acker G, et al. Grading of moyamoya disease allows stratification for postoperative ischemia in bilateral revascularization surgery. Acta Neurochir. 2016; 158:1895–1900

[17] Brown SC, Lam AM. Moyamoya disease--a review of clinical experience and anaesthetic management. Can J Anaesth. 1987; 34(1): 71‐75 PubMed

[18] Bjerregaard J, Pandia MP, Jaffe RA. Occurrence of severe hypotension after indocyanine green injection during the intraoperative period. A A Case Rep. 2013; 1(1): 26‐30 PubMed

[19] Ahn HJ, Kim JA, Lee JJ, et al. Effect of preoperative skull block on pediatric moyamoya disease. J Neurosurg Pediatr. 2008; 2(1): 37‐41 PubMed