Advanced Techniques in Canine and Feline Neurosurgery

An up-to-date discussion of the latest advanced neurosurgical techniques for dogs and cats

In Advanced Techniques in Canine and Feline Neurosurgery, a team of distinguished veterinary practitioners delivers an authoritative and accessible compilation of current best practices for surgery of the spine, neck, and head in dogs and cats. The book focuses on advanced and cutting-edge techniques in the field, offering detailed and step-by-step descriptions of state-of-the-art procedures accompanied by video clips of most.

The authors have developed a companion website that includes additional resources for the techniques described in the book, which provides coverage of percutaneous laser disk fenestration, spinal stabilization, and pituitary surgery. Each chapter presents a detailed description of an operative technique, indications, surgical anatomy, and related and detailed illustrations. Readers will also find: A thorough introduction to the history of veterinary neurosurgery and applications of 3D printing in veterinary neurosurgery In-depth treatments of post-operative radiation therapy of intracranial tumors Comprehensive discussions of the more routine spinal procedures, including cervical ventral slot decompression Explorations of intracranial procedures, including intraoperative ultrasound in intracranial surgery

Perfect for veterinary surgeons and veterinary internal medicine specialists, Advanced Techniques in Canine and Feline Neurosurgery will also earn a place in the libraries of veterinary residents and interns.

List of Contributors xvii

ACVS Foreword xix

ACVIM Foreword xxi

Preface xxiii

About the Companion Website xxv

1 A History of Veterinary Neurosurgery: 1900–2000 1
Don Sorjonen

Introduction 1

Advances in Imaging Techniques 1

Advances in Spinal Procedures 2

Thoracolumbar (T1–S1) 2

Cervical (C1–C7) 5

Advances in Intracranial Procedures 8

Epilogue 11

References 12

2 Applications of 3D Printing in Veterinary Neurosurgery 17
Fred Wininger

Steps of the 3D Printing Process 18

Acquisition 18

Thresholding 18

Segmentation 18

File Format Creation 19

Manifold Manipulation 19

Anatomic Modeling 19

Printing 20

Current Spinal Applications 20

Customized Tools 20

Current Brain Applications 21

Future Applications of 3D Printing in Veterinary Neurosurgery 23

References 23

3 Postoperative Radiation Therapy of Intracranial Tumors 25
M. W. Nolan

Introduction 25

Overview of Radiation Therapy 25

Radiobiology 25

DNA as The Target for Radiation 25

Normal Tissue Injury 26

Rationale for Radiation Fractionation 26

Radiation Physics and Treatment Planning 28

Beam Energy Selection 28

Dose Calculations 28

Target Localization Strategies 29

Delivery Systems 31

Plan Evaluation 32

Specific Tumor Types 33

Meningioma 33

Clinical Data 33

Radiotherapeutic Techniques 34

Glial Tumors 34

Clinical Data 34

Radiotherapeutic Techniques 35

Choroid Plexus Tumors 35

Clinical Data 35

Radiotherapeutic Techniques 35

Spinal Tumors 35

Clinical Data 35

Radiotherapeutic Techniques 36

Stereotactic Radiosurgery and Stereotactic Radiation Therapy 36

References 37

4 Practice and Principles of Neuroanesthesia for Imaging and Neurosurgery 39
Claudio C. Natalini

Introduction 39

Increases in ICP 39

Clinical Signs 39

Dynamics 39

Cerebral Perfusion and Anesthesia 40

The Cushing Reflex and Anesthesia 40

Increases in ICP During Anesthesia 41

ICP and Contrast Myelography 42

Hydrocephalus 42

Neurologic Monitoring: Monitoring Brain State During Anesthesia 42

Modalities of Neurologic Monitoring 42

Electroencephalogram EEG 42

Sensory-Evoked Responses (SERs) and Somatosensory-Evoked Potentials (SSEPs) 42

Glycemic Control 42

Monitoring Nociception 42

Other Modalities 43

Sedation versus General Anesthesia for Imaging 43

Regional Anesthesia for Laminectomy, Hemilaminectomy, and Vertebral Fractures 43

Anesthesia Protocol for Intracranial Surgery 43

References 44

Part I Spinal Procedures 45

5 Cervical Ventral Slot Decompression 47
Andy Shores and Allison Mooney

Cervical IVD Syndrome 47

History 47

Clinical Signs 47

Radiographic Signs 48

Advanced Imaging 49

Indications for Surgery 50

Ventral Approach to the Cervical Spine 50

Decompression of the Cervical Spinal Cord 54

Ventral Slot Method 54

Perioperative and Postoperative Care 58

References 58

6 Thoracolumbar Decompression: Hemilaminectomy and Mini-Hemilaminectomy (Pediculectomy) 59
Brigitte A. Brisson

Indications 59

Procedures 59

Technique: Surgical Approach for Mini-Hemilaminectomy (Video 6.1) 60

Dorsolateral Approach [14–17] (Video 6.2) 60

Variation 61

Recommended Variation 61

Technique: Mini-Hemilaminectomy Procedure 63

Technique: Surgical Approach for Hemilaminectomy 64

Technique: Hemilaminectomy Procedure 65

Removal of Disk Material: Mini-Hemilaminectomy and Hemilaminectomy 66

Closure 67

Complications 67

Postoperative Care 68

References 68

7 Thoracolumbar Disk Fenestration 70
Brigitte A. Brisson

Indications 70

Technique – Surgical Approach 71

Variations 72

Technique – Fenestration Procedure (Video 7.1) 72

Blade Fenestration 73

Power Fenestration 73

Other Requirements 75

Closure 75

Complications 75

Postoperative Care 76

References 76

8 Percutaneous Laser Disk Ablation 78
Danielle Dugat

Introduction 78

Laser Ablation 78

Candidate Selection 79

Procedure Description 80

Procedure Complications and Recurrence 82

Diagnostic Evaluation of PLDA 83

Conclusion 84

References 84

9 The Cranial Thoracic Spine: Approach via Dorsolateral Hemilaminectomy 86
Yael Merbl and Annie Vivian Chen-Allen

Indications 86

Surgical Anatomy 87

Patient Positioning 87

Surgical Technique 88

Postoperative Care 89

References 90

10 Principles in Surgical Management of Locked Cervical Facets in Dogs 91
Andy Shores and Ryan Gibson

Introduction 91

Unilateral Locked Cervical Facets in Humans 91

Clinical Presentation 91

Surgical Techniques 92

Postoperative Care 94

Summary/Conclusions 94

References 95

11 Spinal Stabilization: Cervical Vertebral Column 96
Bianca F. Hettlich

Introduction 96

Preoperative Planning 96

Anatomical Considerations 96

Implant Selection 97

Positioning and Approach 97

Vertebral Distraction 98

Diskectomy 99

Intervertebral Spacer 99

Indication for Additional Decompression 101

Surgical Stabilization 101

Monocortical Screw/PMMA Fixation 101

Vertebral Body Plates 102

Other Techniques 104

Stabilization of Multiple Spaces 105

Postoperative Assessment 105

Complications 106

References 107

12 Stabilization of the Thoracolumbar Spine 109
Simon T. Kornberg and Brigitte A. Brisson

Preoperative Planning 109

Decompression with Stabilization 111

Technique 111

Implant Selection 111

Thoracolumbar Spine 114

Positioning and Approach 114

Implant Selection 114

Spinal Stapling/Segmental Fixation 116

Lumbosacral Spine 118

Anatomy 118

Positioning and Approach 118

Reduction 119

Implant Selection 119

Postoperative Imaging 120

Complications 120

Aftercare 122

Acknowledgments 122

References 122

13 Surgical Management of Congenital Spinal Anomalies 124
Sheila Carrera-Justiz and Gabriel Garcia

Diagnostics 124

Treatment 125

Prognosis 126

Future Directions 127

Summary 127

References 127

14 Lumbosacral Decompression and Foraminotomy Techniques 129
Stef H. Y. Lim and Michaela Beasley

Pathophysiology and Anatomy 129

L7–S1 Foramina Anatomy 129

Diagnosis 130

History and Clinical Signs 130

Physical Examination Findings 130

Orthopedic Examination Findings 130

Neurologic Examination Findings 131

Radiography 131

Myelography (Contrast Study) 132

Computed Tomography (CT) 132

Magnetic Resonance Imaging (MRI) 133

Force Plate Analysis 134

Electrodiagnostics 134

Treatment: Conservative and Medical Therapy 134

Surgery 134

Dorsal Laminectomy 135

Patient Preparation and Positioning 135

Surgical Technique 135

Foraminotomy 136

Facetectomy 137

Distraction, Fusion, and Stabilization 137

Pins and PMMA 137

SOP Plating 137

Surgical Technique 138

Pedicle Screw and Rod Fixation (PSRF) 138

Minimally-Invasive Transilial Vertebral (MTV) Blocking 138

Postoperative Management 139

References 139

15 Surgical Management of Spinal Nerve Root Tumors 143
Ane Uriarte

Introduction 143

Clinical Presentations 143

Meningioma 143

Peripheral Nerve Sheath Tumors 143

Diagnosis 144

Imaging 144

Spinal Meningioma MRI 144

PNST MRI 144

Electrodiagnostics 147

Cytology/Histology 147

Meningiomas 147

PNST 147

Surgery of PNST Within the Spinal Nerves 148

Cervical Approach 148

Positioning 148

Lateral Surgical Approach to Caudal Cervical Foramen After Amputation 148

Dorsal Surgical Approach for Cervical Hemilaminectomy 149

Respiratory Compromise in Cervical Myelopathies 149

Lumbar Approach 150

Approach to the L7–S1 Foramen 150

Postoperative Care 150

Prognosis 151

Radiation Therapy 151

References 151

16 Surgical Management of Craniocervical Junction Anomalies 153
Sofia Cerda-Gonzalez

Indications 153

Surgical Anatomy 154

Patient Preparation and Positioning 155

Surgical Technique 156

Outcomes 159

References 159

17 Ventral Approach to the Cervicothoracic Spine 161
Isidro Mateo

Introduction 161

Surgical Anatomy [10–12] 161

Muscles 161

Vessels 163

Nerves 163

Viscera 163

Surgical Technique [10, 12] 163

Clinical Results 165

Conclusion 167

References 167

Part II Intracranial Procedures 169

18 Intraoperative Ultrasound in Intracranial Surgery 171
Alison M. Lee, Chris Tollefson and Andy Shores

Introduction 171

Artifacts in Imaging 172

Accuracy of Intraoperative Ultrasound 173

Scanning Procedure and Equipment 173

Appearance of Tumor on Ultrasound 175

Ultrasound Guided Procedures 177

Conclusion 177

References 177

19 Brain Biopsy Techniques 179
John Rossmeisl and Annie Chen

Introduction 179

Indications and Contraindications 179

Frame-based Stereotactic Brain Biopsy (SBBfb) 179

SBBfb Technique 181

Preoperative Evaluation 181

Headframe Placement and Acquisition of Stereotactic Images 181

SBBfb Planning 181

SBBfb Procedure 183

Postoperative Care and Adverse Events 184

Processing of Brain Biopsy Specimens 184

Frameless Stereotactic Brain Biopsy (SBBfl) 185

SBBfl Technique 185

Attachment of the Fiducial Markers 185

Acquisition of Magnetic Resonance Images 186

Registration Procedure 186

Trajectory Planning 187

Brain Biopsy 187

Biopsy Sample Processing 187

Conclusion 187

References 188

20 Surgical Management of Sellar Masses 190
Tina Owen, Annie Chen-Allen and Linda Martin

Introduction 190

Case Selection 191

Preoperative Work up 192

Neurologic Exam 192

Preoperative Testing and Diagnostics 193

Endocrine Testing 193

Brain Imaging 193

Imaging of Pituitary Masses 194

Imaging of Non-Pituitary Sellar Masses 195

Surgery 196

Anatomy 196

Localization 196

Positioning 197

Approach 197

Surgical Outcome 198

In Hospital Care 200

Postoperative Management and Monitoring 200

Postoperative Complications 200

Endocrine and Metabolic Complications 200

Respiratory Complications 203

Neurologic Complications 204

Procedural Related Complications 204

Long term Follow Up 205

References 206

21 Surgical Management and Intraoperative Strategies for Tumors of the Skull 211
Jonathan F. McAnulty

Osteosarcoma and Multilobular Osteochrondrosarcoma of the Cranium 211

Diagnosis and Characterization 212

Surgical Planning and Treatment 212

Exposure 212

Challenges in Skull Tumor Resection 214

Parietal Calvarial and Dorsal Frontal Bone Lesions 214

Frontal Bone within the Orbit and Sphenoid Bone Lesions 215

Occipital Bone Lesions 215

MRI Assessment of Blood Flow to the Transverse Sinuses 216

Slow Occlusion of Flow from the DSS to the Transverse Sinus Using a Balloon Catheter 217

Extension of Tumor to the tentorium Cerebelli 218

Zygomatic Arch and Ramus of the Mandible 218

Complications and Risks 219

Cranioplasty 220

References 221

22 Surgical Management of Intracranial Meningiomas 223
R. Timothy Bentley

Introduction 223

Anatomy 223

Transfrontal Craniotomy (Bilateral Transfrontal Craniotomy) 225

Technique 225

Closure 227

Modifications 228

The Falx Cerebri and the Dorsal Sagittal Sinus (DSS) 229

Rostrotentorial Craniectomy/Craniotomy (Lateral Craniectomy/Craniotomy) 231

Technique 232

Closure: Craniectomy vs Craniotomy 233

Combined Rostrotentorial–Transfrontal Approach 234

Suboccipital Craniectomy (See Also Chapter 24 Surgery of Caudal Fossa Tumors) 235

Technique 235

Closure 236

Meningioma Resection and Instrumentation 236

Simpson Classification of Meningioma Resection in Humans (Table 22.2) 237

Substitutes for Resected Dura Mater 237

Complications and Mitigation Strategies 239

References 239

23 Lateral Ventricular Fenestration 241
Andy Shores

Introduction 241

Rationale 241

Technique 242

Potential Complications 243

Discussion 243

References 248

24 Surgery of the Caudal Fossa 249
Beverly K. Sturges

Anatomy 249

Indications for Surgery 250

Preoperative Assessment and Anesthetic Management 251

Surgical Positioning 251

Surgical Approach(es) to the Caudal Fossa 252

Midline Occipital Approach [3–5] 252

Extended Lateral Approach with Occlusion of The Transverse Sinus [3, 6] 255

Lateral Approach to The Cerebellum in Cats [8] 258

Closing and Reconstruction 258

Postoperative Care 259

Complications 260

References 261

25 Transzygomatic Approach to Ventrolateral Craniotomy/Craniectomy 262
Martin Young and Sandy Chen

Introduction 262

Patient Positioning/Preparation 262

Surgical Procedure 263

References 266

Index 269