Microsurgical and Endoscopic Approaches to the Skull Base: Anatomy, Tactics, and Techniques

Description

The one-stop guide to microsurgical and endoscopic treatment of skull base lesions from global experts A deep knowledge of regional anatomy, improved understanding of pathologies and their behaviors, technological advances, and multidisciplinary collaboration have led to more effective treatments for once inoperable skull base lesions. Microsurgical and Endoscopic Approaches to the Skull Base: Anatomy, Tactics, and Techniques by renowned skull base neurosurgeons Luis A. B. Borba and Jean G. de Oliveira presents a balanced, anatomy-based perspective on microsurgical and endoscopic approaches to manage these highly challenging lesions. The text leverages the best current scientific literature on this topic and insights from global skull base surgery experts. Organized into 9 sections and 52 chapters, the book starts with discussion of microsurgical and endoscopic instrumentation and neurophysiological monitoring. The subsequent sections cover diverse approaches for skull base lesions involving the sphenoid and parasellar, orbit, anterior fossa, cavernous sinus, temporal bone and jugular foramen, and foramen magnum regions. Each of these sections starts with an introduction, followed by a microsurgical description of the anatomy of the impacted region. Key Highlights Contributions from an impressive group of internationally renowned neurosurgeons and otolaryngologists specializing in skull base pathologiesIndications, preoperative and postoperative concerns, nuances, pitfalls, tactics, techniques, and references for further reading provide a comprehensive guide to treatmentA stepwise description of the approach, high-quality four-color drawings, and illustrative cases facilitate acquisition and retention of knowledgeHigh-quality figures provide greater visual insights and step-by-step guidance on how to perform specific procedures This unique textbook will help residents, fellows, and practitioners in neurosurgery and otolaryngology make an evidenced-based decision on using the most effective microsurgical and/or endoscopic approach to achieve the best outcomes in patients with skull base lesions. This book includes complimentary access to a digital copy on https://medone.thieme.com. Microsurgical and Endoscopic Approachesto the Skull Base: Anatomy, Tactics, and Techniques MedOne Access Information Title Copyright Contents Videos Foreword Preface Acknowledgment Contributors Section I Instrumentals and Equipment 1 Instrumentation for Endoscopic Skull Base Surgery 1.1 Introduction 1.2 Special Requirements for Endoscopic Approaches 1.3 Patient Positioning and Operating Room Setup 1.3.1 Positioning 1.3.2 Operating Room Setup 1.4 Endoscopes and Video Systems 1.4.1 Types of Endoscopes: Function and Management 1.4.2 Irrigation Sheaths and Pumps 1.4.3 Pneumatic Holding Arms 1.4.4 Light Sources 1.4.5 High-Definition Digital Cameras and Monitors 1.5 Surgical Instruments 1.5.1 Microdrills Handpieces and Burrs 1.5.2 Microinstruments, Dissectors, and Micro-Ultrasonic Aspirator (microCUSA) 1.6 Neuromonitoring and Neuronavigation in Endoscopic Skull Base Surgery 1.7 Conclusion References 2 Neurosurgical Instrumentation 2.1 Operating Room 2.2 Microscope 2.3 Neuroendoscopy 2.4 Patient Positioning 2.5 Instruments 2.5.1 Bipolar Coagulator 2.5.2 Scissors 2.5.3 Dissectors 2.5.4 Needle, Suture, and Needle Holder 2.5.5 Brain Retractor 2.5.6 Suction 2.5.7 Drills 2.5.8 Tissue Forceps 2.5.9 Aneurysm and Vascular Clips References 3 Neurophysiological Monitoring in Skull Base Surgery 3.1 Introduction 3.2 Electromyography (EMG) 3.2.1 Background 3.2.2 Cranial Nerves III, IV, and VI 3.2.3 Cranial Nerve V 3.2.4 Cranial Nerve VII 3.2.5 Cranial Nerves IX, X, and XII 3.2.6 Cranial Nerve XI 3.3 Brainstem Auditory Evoked Potential (BAEP) 3.4 Visual Evoked Potential (VEP) 3.5 Cases 3.5.1 Case 1 3.5.2 Case 2 3.5.3 Case 3 3.6 Conclusion References Section II Anterior Approaches Transnasal and Transoral 4 Anatomical Landmarks of Anterior Approaches: An Endoscopic View 4.1 Introduction 4.2 Nasal Cavity 4.3 Anatomy of the Transshpenoidal, Transtuberculum, and Transplanum Approaches 4.4 Anatomy of the Transethmoidal Transcribriform Approach 4.5 Anatomy of the Transclival and Craniovertebral Junction Approaches 4.6 Anatomy of the Transpterygoid and Infratemporal Approaches References 5 Direct Microscopic Transsphenoidal Surgery with Hybrid Use of Endoscopy 5.1 Introduction 5.2 Direct Endonasal Microscopic TSS with Hybrid Use of Endoscopy 5.2.1 Patient Preparation 5.2.2 Endonasal Stage I 5.2.3 Sphenoid Sinus Stage II 5.2.4 Intrasellar Stage III 5.2.5 Suprasellar Stage IV 5.2.6 Hybrid Use of Endoscopy 5.2.7 Closure 5.3 Conclusion References 6 The Extended Transsphenoidal Approach (Mid-maxillotomy) to the Clivus 6.1 Introduction 6.2 Anatomical Background 6.3 Indications 6.4 Surgical Technique 6.5 Patient Positioning 6.6 Incision and Soft Tissues Dissection 6.7 Osteotomy 6.8 Nasal Dissection and Clivus Stage 6.9 Closure References 7 The Microsurgical Transoral Approach 7.1 Introduction 7.2 Anatomy of the Craniovertebral Junction 7.3 Indications 7.4 Preoperative Evaluation 7.5 Operative Technique 7.6 Endoscopic Endonasal Approach 7.7 Postoperative Care and Complications 7.8 Conclusion References 8 Elongated and Pediculated Pericranial Flap for Endonasal Reconstruction of the Entire Ventral Skull Base 8.1 Background 8.2 Introduction 8.3 Objective 8.4 Methods 8.5 Surgical Technique 8.6 Results 8.7 Discussion 8.8 Conclusion References 9 Expanded Endoscopic Endonasal Approaches to the Sellar and Parasellar Regions 9.1 Introduction 9.2 Endoscopic Anatomy of the Sellar and Parasellar Regions 9.2.1 Anterior Skull Base 9.2.2 Sellar and Parasellar Regions 9.2.3 Clival Region and Posterior Skull Base 9.3 Surgical Technique, Technical Nuances, and Complications 9.3.1 Trans-sellar Approach 9.3.2 Transtuberculum Transplanum 9.3.3 Trans-cavernous and Trans-clival (Superior Third) 9.4 Illustrative Cases 9.4.1 Case 1 9.4.2 Case 2 9.5 Conclusion References 10 The Endoscopic Transpterygoid Approach to the Parasellar and Infratemporal Fossa 10.1 Introduction 10.2 Anatomical Landmarks and Surgical Strategies 10.2.1 Zone 1: Medial Petrous Apex (Infrapetrous) 10.2.2 Zone 2: Petroclival Approaches (Infrapetrous) 10.2.3 Zone 3: Inferior Cavernous Sinus and Quadrangular Space (Suprapetrous) 10.2.4 Zone 4: Superior Portion of the Cavernous Sinus (Suprapetrous) 10.2.5 Zone 5: Transpterygoid Infratemporal Approach (Suprapetrous) 10.3 Limits of the Approach 10.4 Conclusion References 11 Endoscopic Endonasal Transclival Approach to the Posterior Fossa 11.1 Introduction 11.1.1 Extradural Lesions 11.1.2 Intradural Lesions 11.2 Anatomy 11.3 Tactics and Techniques 11.3.1 Imaging 11.3.2 Technical Approach 11.3.3 Skull Base Reconstruction 11.4 Conclusions References Section III Surgical Approaches to the Orbit 12 Microsurgical Anatomy of the Orbit 12.1 Historical Account 12.2 The Rule of Seven of the Orbit 12.3 Orbital Bones 12.4 Orbital Muscles and Vessels 12.5 Orbital Nerves 12.6 Topographical Relationships and Orbital Surgical Approaches 12.7 Conclusion References 13 Lateral Orbitotomy Approach to the Orbit and Cavernous Sinus 13.1 Historical Background 13.2 Relevant Surgical Anatomy 13.3 Indications 13.4 Surgical Technique 13.5 Advantages and Disadvantages 13.6 Surgical Outcome and Complications 13.7 Illustrative Cases 13.7.1 Case 1: Cavernous Sinus Lesion Biopsy 13.7.2 Case 2: SOF Lesion Removal 13.7.3 Case 3: Temporal Pole Tumor Removal 13.8 Conclusion References 14 Transcranial Approaches to the Orbit 14.1 Historical Background 14.2 Relevant Surgical Anatomy of the Orbit 14.2.1 Structure of the Orbit 14.2.2 Nerves of the Orbit 14.2.3 Blood Supply to the Orbit 14.2.4 Muscles of the Orbit 14.2.5 Lacrimal Gland 14.3 Indications for Transcranial Approaches to the Orbit 14.4 Surgical Techniques 14.4.1 Preoperative Preparation 14.4.2 The Subfrontal Route 14.4.3 The Supraorbital Route 14.4.4 The Frontotemporal Approach 14.4.5 The Superolateral Approach 14.5 General Considerations to Avoid Postoperative Complications 14.5.1 Nasal Sinuses 14.5.2 Orbital Fat 14.5.3 Brain Retraction 14.5.4 Reconstruction of Orbital Walls 14.6 Illustrative Cases 14.6.1 Case 1: Cavernous Hemangioma of the Superomedial Orbital Quadrant 14.6.2 Case 2: Recurrent Pleomorphic Adenoma of the Lacrimal Gland with Intracranial Extension 14.6.3 Case 3: Meningioma of the Lateral Orbit 14.7 Conclusion References 15 The Medial Endoscopic Approach to the Orbit 15.1 Introduction 15.2 Materials and Methods 15.3 Surgical Technique 15.4 Illustrative Cases 15.4.1 Case 1 15.4.2 Case 2 15.5 Discussion 15.6 Conclusion References Section IV Anterior Approaches to the Skull Base 16 Microsurgical Anatomy of the Anterior Skull Base Through a Cranial View 16.1 Bony Anatomy 16.2 Neurovascular Relationships 16.3 Orbit References 17 Microsurgical Anatomy of the Anterior Skull Base as Seen Through the Endonasal Endoscopic View 17.1 History 17.2 Guiding Principles in Ventral Skull Base Surgery 17.3 Microsurgical Anatomy of the Anterior Cranial Base 17.4 Endocranial Surface of the Anterior Cranial Base: Overview 17.5 Sinonasal Anatomy 17.5.1 The Outer Circumferential-Radial Corridor Overview 17.6 Anatomy from Frontal Sinus to Planum Sphenoidale (Transcribriform Corridor) 17.6.1 Outer Circumferential-Radial Corridor 17.6.2 Inner Circumferential-Radial Corridor (ICRC) 17.7 Anatomy from Planum to the Superior Edge of the Sella (Transtuberculum/Transplanum Corridor) 17.7.1 Outer Circumferential-Radial Corridor (OCRC) 17.7.2 Inner Circumferential-Radial Corridor (ICRC) 17.8 Anatomy of the Orbit (Transorbital Corridor) 17.8.1 Outer Circumferential-Radial Corridor (OCRC) 17.8.2 Inner Circumferential-Radial Corridor (ICRC) 17.9 Conclusion Suggested Readings 18 Eyebrow Supraorbital Approach for Skull Base Lesions 18.1 History of Supraorbital Craniotomy 18.2 Relevant Surgical Anatomy 18.3 Anatomical Limitations and Surgical Applications 18.4 Surgical Technique 18.4.1 Positioning and Anesthesia 18.4.2 Skin Incision 18.4.3 Craniotomy 18.4.4 Intradural Dissection 18.4.5 Closure 18.5 Advantages and Disadvantages 18.6 Illustrative Cases 18.6.1 Case 1 18.6.2 Case 2 18.7 Conclusion References 19 Transbasal/Transcranial Microsurgical Approaches to Anterior Fossa Meningiomas 19.1 Introduction 19.2 Incidence 19.3 Clinical Features 19.3.1 Tuberculum Sellae Meningiomas 19.3.2 Olfactory Groove Meningiomas 19.3.3 Anterior Fossa Floor Meningiomas 19.4 Diagnostic Imaging 19.4.1 Skull Radiography 19.4.2 Digital Subtraction Angiography of the Internal Carotid Artery 19.4.3 Computed Tomography (CT) 19.4.4 Magnetic Resonance Imaging (MRI) 19.5 Surgical Treatment 19.6 Surgical Approaches 19.7 Preoperative Assessment 19.8 Anesthesia 19.9 Surgical Technique for the Approach of Tuberculum Sellae Meningiomas 19.9.1 Positioning 19.9.2 Frontotemporal Craniotomy with Resection of the Supraorbital Rim 19.9.3 Lateral Fissure Splitting 19.9.4 Tumor Resection 19.9.5 Optic Nerves and Chiasm 19.9.6 Arterial Dissection 19.9.7 Pituitary Stalk 19.9.8 Invasion of the Optic Canal and the Cavernous Sinus 19.9.9 Tumor Implantation 19.9.10 Closure 19.10 Surgical Technique for the Approach to Olfactory Groove Meningiomas 19.10.1 Positioning 19.10.2 Bifrontal Craniotomy 19.10.3 Dura Mater Incision 19.10.4 Tumor Resection 19.10.5 Arterial Dissection 19.10.6 Optic Nerves and Chiasm 19.10.7 Tumor Implantation 19.10.8 Closure 19.10.9 Subcranial Approach 19.11 Surgical Technique for the Approach to Meningiomas of the Anterior Fossa Floor 19.12 Postoperative Care 19.13 Results 19.14 Visual Outcome 19.15 Complications 19.16 Damage to the Pituitary Stalk 19.17 Surgical Approach 19.18 Retraction of Brain Tissue 19.19 Damage to Vessels Close to the Tumor 19.20 Mortality References 20 Orbitocranial Approach 20.1 Introduction 20.1.1 Historical Background 20.1.2 Indications 20.2 Surgical Technique 20.2.1 Position 20.2.2 Skin Incision 20.2.3 Scalp Elevation 20.2.4 Craniotomy 20.2.5 Removal of the Orbital Rim 20.2.6 Reconstruction 20.3 Cases 20.3.1 Case 1 20.3.2 Case 2 References 21 The Extended Endoscopic Endonasal Approach to the Anterior Fossa 21.1 Introduction 21.2 Surgical Approaches 21.2.1 The Transplanum Transtuberculum approach 21.2.2 Surgical Technique - Transplanum Transtuberculum Approach 21.2.3 The Transcribriform Approach 21.2.4 Surgical Technique Transcribriform Approach 21.2.5 Reconstruction 21.3 Clinical Cases 21.4 Conclusion References Section V Anterolateral Approaches 22 Microsurgical Anatomy of the Cavernous Sinus 22.1 Introduction 22.2 The Sinus 22.3 Osseous Relationships 22.4 Nerves 22.5 Ligaments 22.6 Internal Carotid Artery and Branches 22.7 Venous Compartments 22.8 Cavernous Sinus Triangles 22.8.1 Clinoidal Triangle 22.8.2 Oculomotor Triangle 22.8.3 Supratrochlear Triangle 22.8.4 Infratrochlear Triangle (Parkinson’s Triangle) 22.9 Middle Fossa and Paraclinoid Triangles 22.9.1 Anteromedial Triangle 22.9.2 Anterolateral Triangle 22.9.3 Posterolateral Triangle (Glasscock’s Triangle) 22.9.4 Posteromedial Triangle (Kawase’s Triangle) 22.9.5 Paraclival Triangles References 23 Transcavernous Approach 23.1 Introduction 23.1.1 Anatomy of the Cavernous Sinus and Temporal Fossa 23.1.2 Triangles of the Cavernosus Sinus 23.1.3 Triangles of the Middle Fossa 23.2 The Pretemporal Craniotomy 23.2.1 Positioning 23.2.2 Trichotomy 23.2.3 Incision 23.2.4 The Temporal Muscle 23.3 Craniotomy 23.3.1 The Exposure of the Lateral Wall of the Cavernous Sinus 23.3.2 The Anterior Clinoid 23.3.3 The Meckel’s Cave 23.3.4 Anterior Petrosectomy 23.3.5 Posterior Clinoid 23.4 Discussion References 24 Microsurgical Anatomy of the Middle Fossa and Petrous Apex 24.1 Background 24.2 Anatomy 24.2.1 Endocranial Surface and Its Limits 24.2.2 The Foramens of the Middle Fossa 24.2.3 Petrous Apex 24.3 The Middle Fossa as a Surgical Corridor 24.4 Cases 24.4.1 Case 1 24.4.2 Case 2 24.4.3 Case 4 24.5 Conclusions References 25 Pterional Approach 25.1 Introduction 25.2 Historical Landmarks 25.3 Indications 25.4 Step-by-Step Procedure 25.4.1 Positioning 25.4.2 Trichotomy 25.4.3 Skin Incision 25.4.4 Interfascial Dissection 25.4.5 Temporal Muscle Dissection 25.4.6 Craniotomy 25.4.7 Sphenoid Wing Drilling 25.4.8 Dural Opening 25.4.9 Neurosurgical Routes 25.4.10 Dural Closure 25.4.11 Cranioplasty 25.4.12 Muscle Reconstruction 25.4.13 Variations 25.5 Conclusion 25.6 Illustrative Cases References 26 Anterolateral Skull Base: Anatomy, Surgical Technique, and Nuances 26.1 Surgical Anatomy 26.1.1 Sagittal and Axial Unlocking: A Wider Exposure to Skull Base 26.2 Extended Skin Incision and Craniotomy 26.3 Orbitomeningeal Band Dissection 26.4 Pericavernous Dissection Techniques 26.5 Anterior Clinoidectomy 26.6 Posterior Clinoidectomy 26.7 Petrous Anatomy and Anterior Petrosectomy 26.8 Carotid Anatomy and Relations References 27 Pretemporal Approach 27.1 Introduction 27.2 Advantages of the Pretemporal Approach 27.3 Anatomical Exposure and Surgical Access 27.4 Indications 27.5 Step-by-Step Procedure 27.5.1 Patient Positioning 27.5.2 Skin Incision 27.5.3 Preservation of the STA 27.5.4 Facial Nerve Branches Preservation 27.5.5 Mobilization of the Temporal Muscle 27.5.6 Craniotomy 27.5.7 Variations and Alternative Routes 27.6 Microsurgical Access to the Interpeduncular Fossa Region 27.7 Conclusion 27.8 Illustrative Cases References 28 Cranio-Orbit-Zygomatic (COZ) Approach 28.1 Background 28.2 Indications 28.3 Technique 28.3.1 Positioning 28.3.2 Skin Incision and Pericranial Flap 28.3.3 Subfascial Dissection 28.3.4 Zygomatic Osteotomy 28.3.5 Mobilizing the Temporal Muscle 28.4 Craniotomy 28.4.1 Cranial Flap 28.4.2 Orbital Osteotomy 28.5 Closure 28.6 Limitations 28.7 Complications and Avoidance 28.8 Illustrative Cases 28.9 Conclusions References 29 Anterior Petrosal Approach 29.1 Introduction 29.1.1 Anatomical Background 29.1.2 Indications 29.2 Surgical Technique 29.2.1 Patient Positioning 29.2.2 Skin Incision and Soft Tissue Dissection 29.2.3 Zygomatic Osteotomy 29.2.4 Temporalis Muscle Reflection 29.2.5 Craniotomy 29.2.6 Middle Fossa Dissection 29.2.7 Closure 29.2.8 Complications References 30 Endoscopic Approach to the Cavernous Sinus Area: Surgical Technique 30.1 Introduction 30.2 Technical Equipment and Surgical Supplies 30.3 Preoperative Preparation Stage 30.3.1 Setup of the Patient and the Surgeon 30.4 Surgical Technique 30.4.1 Stages of the Surgical Procedure 30.5 A Clinical Case 30.6 Perspectives References Section VI Posterolateral Approaches 31 Temporal Bone Anatomy 31.1 Introduction 31.2 Surgical Anatomy 31.2.1 The Squamous Portion 31.2.2 The Tympanic and Styloid Portions 31.2.3 The Mastoid Portion 31.2.4 The Petrous Portion 31.3 Craniotopographic Relationships Suggested Readings 32 Microsurgical Anatomy of the Jugular Foramen 32.1 Introduction 32.2 Anatomy 32.3 Bone and Osseous Relations 32.4 Meningeal Structure and Cranial Nerves 32.5 Vascular Structures Related to the Jugular Foramen 32.6 Muscular Relationships 32.7 Conclusions References 33 Anatomy of the Cerebellopontine Angle: A Microscopic Perspective 33.1 A Brief Historical Review 33.2 A Brief Introduction to the Anatomy of the CPA: A Detailed Look 33.3 Surgical Anatomy of the CPA Region 33.3.1 Continent: Walls of the CPA 33.3.2 Content: The Neurovascular Complexes References 34 The Posterior Retrolabyrinthine Presigmoid Approach 34.1 Background 34.2 Indications 34.3 Surgical Technique 34.3.1 Patient Positioning 34.3.2 Soft Tissue Work 34.3.3 Bony Work 34.3.4 Closure 34.4 Limitations 34.5 Complications and Avoidance 34.6 Illustrative Cases 34.7 Conclusions References 35 Retrosigmoid Approach 35.1 Introduction 35.1.1 Anatomical Background 35.1.2 Indications 35.2 Surgical Technique 35.2.1 Patient Positioning 35.2.2 Skin Incision and Soft Tissue Dissection 35.2.3 Craniotomy 35.2.4 Dural Opening and Intradural Steps 35.2.5 Closure 35.2.6 Complications References 36 Endoscopic Assisted Approach to the Cerebellopontine Angle 36.1 History 36.2 CPA Anatomy 36.3 Advantages/Disadvantages 36.4 Indications 36.5 Vestibular Schwannoma 36.5.1 Vestibular Schwannoma Endoscopic Assisted Approach Technique 36.6 Trigeminal Schwannomas 36.6.1 Trigeminal Schwannoma Endoscopic Assisted Approach Technique 36.7 Epidermoid Tumors 36.8 Meningiomas 36.9 Other Tumors References 37 Infratemporal Fossa Approach to the Jugular Foramen 37.1 Introduction 37.2 Anatomy 37.3 Technique and Tactics 37.3.1 Positioning 37.3.2 Incision and Superficial Dissection 37.3.3 Muscle and Cervical Region Dissection 37.3.4 Mastoidectomy and Craniotomy 37.3.5 Tactics 37.4 Closure 37.5 Conclusion References 38 The Facial Reanimation: Multidisciplinary Approaches 38.1 Introduction 38.2 Different Facial Nerve Reconstruction Techniques 38.2.1 Direct Neurorrhaphy 38.2.2 Hypoglossal-Facial Nerve Neurorrhaphy 38.2.3 Alternatives to Classic Hypoglossal-Facial Neurorrhaphy 38.2.4 Masseteric-Facial Nerve Neurorrhaphy 38.2.5 Accessory-Facial Nerve Neurorrhaphy 38.3 Transfacial Anastomosis (Cross-Face Facial Nerve Anastomosis) 38.4 Neuromuscular Transplant 38.5 Conclusion References Section VII Posterior and Lateral Approaches to the Craniocervical Junction 39 Microsurgical Anatomy of the Foramen Magnum 39.1 Brief Historical Review 39.2 Introduction 39.3 Surgical Anatomy of the FM Region 39.4 Extradural Stage 39.4.1 Nuchal Muscles and V3 Segment 39.5 Anatomy of the VA 39.5.1 Vertebral Venous Plexus 39.5.2 Nuchal Lines Method 39.6 Bone Structure and Articulations 39.6.1 Occipital Bone 39.6.2 Occipital Condyles 39.6.3 Atlanto-occipital Joints 39.6.4 Atlanto-axial Joints 39.7 Dural Stage 39.7.1 Dural Venous Sinuses 39.7.2 Surgical Tips 39.8 Intradural Stage 39.8.1 Neural Elements 39.8.2 Denticulate Ligament 39.8.3 Cerebellum 39.8.4 Nerves 39.8.5 Vascular Elements References 40 Far-Lateral Approach and Its Variants 40.1 Background 40.2 Indications 40.3 Surgical Technique 40.3.1 Patient Positioning 40.3.2 Skin Incision 40.3.3 Intradural versus Extradural Approach 40.3.4 Soft Tissue Dissection 40.3.5 Bone Flap and Dura Opening 40.3.6 Condyle Removal: The Transcondylar Approach 40.3.7 Closure 40.4 Complications and Avoidance 40.5 Illustrative Cases 40.5.1 Case 1 40.5.2 Case 2 References 41 Surgical Treatment for Atlantoaxial Instability 41.1 Introduction 41.2 Atlantoaxial Dislocation 41.3 Basilar Invagination 41.4 Chiari 1 Malformation and Syringomyelia 41.5 Central or Axial Atlantoaxial Facetal Instability 41.6 Investigations 41.7 Surgery 41.7.1 Operative Technique for Lateral Mass Plate (or Rod) and Screw (Monoaxial or Polyaxial) Fixation 41.8 Complication Avoidance 41.9 Craniovertebral Realignment for Group A Basilar Invagination: Role of Interarticular Cages 41.10 Technique 41.11 Atlantoaxial Fixation for Group B Basilar Invagination References 42 Endoscopic Approach to the Craniocervical Junction 42.1 Introduction 42.2 The Endoscopic Endonasal Approach 42.3 Surgical Technique and Anatomic Landmarks 42.4 The Endoscopic Transoral Approach 42.5 The Endoscopic Transcervical Approach 42.6 Surgical Technique 42.7 Approach Selection 42.7.1 Preoperative Imaging 42.8 Patient Selection 42.9 Limitations to the Endoscopic Approaches 42.10 Conclusion References Section VIII Approaches to the Posterior Incisural Space 43 Anatomy of the Posterior Incisural Space: Microscopic Perspective 43.1 Introduction 43.2 Objective 43.3 Microsurgical Anatomy 43.4 Overview 43.4.1 The Posterior Incisural Space 43.4.2 The Inferior and Middle Surface of the Posterior Temporal Lobe and the Occipital Lobe 43.4.3 The Tentorium 44 Anatomy of the Posterior Incisural Space: Endoscopic Perspective 44.1 Introduction 44.2 History 44.3 Anatomy 44.4 Endoscopic-Assisted Microsurgery 44.5 Conclusion References 45 The Occipito-polar Approach: Study of the Occipital lnterhemispheric Supratentorial Transtentorial Transfalcine Approach 45.1 Introduction 45.2 Patient Series, Anatomical Study, and Methods 45.2.1 Anatomical Study and Patient Series 45.2.2 Surgical Technique 45.3 Illustrative Surgical Cases 45.3.1 Case 1 45.3.2 Case 2 45.4 Evaluation of Surgical Outcomes of the Patients 45.5 Results 45.5.1 Anatomical Study of the Occipito-polar Approach 45.5.2 Surgical Cases 45.6 Discussion 45.7 Conclusions 45.8 Disclosures References 46 Supracerebellar Infratentorial Approach: Microsurgical Perspective 46.1 Introduction 46.2 Preoperative Evaluation 46.3 Surgical Approach and Operative Techniques 46.4 Median SCIT Approach 46.5 Paramedian SCIT Approach 46.6 Lateral and Extreme Lateral SCIT Approach 46.7 Contralateral SCIT Approach 46.8 Intraoperative Techniques 46.9 Postoperative Management References 47 Supracerebellar Infratentorial Approach: Endoscopic Perspective 47.1 Introduction 47.2 Evolution of a Surgical Approach 47.2.1 Supracerebellar Infratentorial Approach 47.3 Optimization of Gravity Retraction: Sitting Position 47.4 Use of the Endoscope in Neurosurgery 47.5 Nuances of the Surgical Technique 47.6 Sitting Position 47.7 Off-Midline, Minimally Invasive Craniotomy 47.8 Selection of Craniotomy Location 47.9 Representative Cases 47.9.1 Case 1 47.9.2 Case 2 47.9.3 Case 3 References 48 Supracerebellar Transtentorial Approach 48.1 Introduction 48.2 Historical Landmarks 48.3 Indications 48.4 Preoperative Assessment 48.5 Surgical Technique 48.5.1 Anesthesia and Intraoperative Neurophysiological Monitoring 48.5.2 Positioning 48.5.3 Skin Incision and Muscle Management 48.5.4 Craniotomy 48.5.5 Dural Opening 48.5.6 Microsurgical Dissection 48.5.7 Tentorial Opening/Resection 48.5.8 Microsurgical Anatomy 48.5.9 Closure 48.6 Conclusion 48.7 Illustrative Cases References Section IX Cerebrovascular Management for Skull Base Surgery 49 STA-MCA Bypass 49.1 Introduction 49.2 Historical Landmarks 49.3 Indications 49.4 Surgery 49.4.1 Preoperative Preparation 49.4.2 Anaesthesia and Monitoring 49.4.3 The Technique 49.4.4 Closure 49.4.5 Postoperative Care 49.4.6 Follow-up 49.5 Conclusion References 50 High-Flow Cervical Carotid Artery to Middle Cerebral Artery Bypass 50.1 Introduction 50.2 Indications and Preoperative Management 50.3 Microsurgical Anatomy 50.4 Interposition Graft 50.5 Recipient Site 50.6 Donor Site 50.7 Technical Nuances 50.8 Bypass Patency and Intraoperative Troubleshooting 50.9 Conclusion References 51 Intracranial–Intracranial Bypass for Treatment of Complex Vascular Lesions and Tumors 51.1 Introduction 51.2 Intracranial-Intracranial (IC-IC) Bypass 51.2.1 Single 51.2.2 With Graft Interposition 51.2.3 Combined 51.3 Preoperative Assessment Study 51.4 Surgical Procedure 51.5 Discussion 51.6 Conclusion References 52 Endoscopic Endonasal Approaches for the Treatment of Vascular Lesions 52.1 Introduction 52.2 Endoscopic Anatomy during Treatment of Vascular Lesions 52.2.1 Vascular Anatomy 52.2.2 Neural Anatomy 52.2.3 Bony Anatomy 52.2.4 Dural Anatomy 52.3 Intraoperative Fluorescence and Imaging Tools in EEA for Vascular Lesions 52.3.1 Endoscopic Indocyanine Green (endoICG) 52.3.2 Sodium Fluorescein 52.3.3 Intraoperative 3D Angiography (3D-DSA) 52.4 Reconstructive Techniques in EEA 52.4.1 Nasal Phase 52.4.2 Sphenoidal Phase 52.4.3 Sealing/Packing Phase 52.5 Operative Nuances 52.6 Aneurysms 52.6.1 Anterior Circulation Aneurysms 52.6.2 Posterior Circulation Aneurysms 52.7 Complications 52.8 Cavernous Malformations 52.8.1 Technical Nuances 52.8.2 Surgical Technique 52.8.3 World Experience 52.9 Vascular Tumors of the Skull Base 52.9.1 Preoperative Evaluation 52.9.2 Intraoperative Technical Nuances 52.10 Conclusion References Index Additional MedOne Access Information