Neurosurgery
NEUROLOGICAL SURGERY
Chief: Christian B. Kaufman, MD, FAANS
Division of Neurosurgery, Children’s Mercy Kansas City
Academic Positions:
Associate Professor, UMKC School of Medicine
Clinical Associate Professor of Neurosurgery, University of Kansas Medical Center
HOW MUCH OF OUR BRAIN DO WE USE?
The 10% Myth:
Common belief is that humans only use 10% of their brain.
False implication:
If true, an average human brain (approx. 3 lbs) would only need 0.3 lbs to function, akin to a sheep.
Neurosurgeons would have a 90% margin of error in operating.
PET scans would not show 90% of the brain in use.
Evolution and Energy Consumption:
The brain utilizes a disproportionate amount of energy, suggesting that wasting 90% would have led to evolutionary disadvantages, favoring smaller brains instead.
Scientific Consensus:
No credible scientific evidence supports the notion that only 10% of the brain is used; all areas are utilized for various functions.
NEUROLOGICAL SURGERY
Definition:
A medical discipline and surgical specialty dedicated to treating conditions affecting the central nervous system (CNS) and its supportive structures.
Areas treated include:
Pathologies affecting the brain, hypophysis (pituitary gland), spinal cord, and peripheral nervous system.
Surgical involvement necessitates knowledge of vascular supply: intracranial, extracranial, and spinal vasculature.
TREATMENT IN NEUROLOGICAL SURGERY
Overall Treatment Scope:
Encompasses:
Non-operative management:
Prevention, diagnosis (including image interpretation), neurocritical intensive care, rehabilitation.
Operative management:
Includes endovascular surgery, functional/restorative surgery, stereotactic radiosurgery, spinal fusion, and related instrumentation.
Definition by the American Board of Neurological Surgery.
NEUROSURGICAL TRAINING
Residency:
Duration: 7 years with no internship.
Research: 1+ years required.
Additional training includes:
Neurology
Neuropathology
Neuroradiology
Neurocritical Care
Fellowship:
Duration: 1 year (2 for some specialties).
Specializations available:
Pediatric neurosurgery
Neuroendovascular surgery
Neurocritical care
Skull base neurosurgery
Cerebrovascular neurosurgery
Neurosurgical oncology
Peripheral nerve surgery
Epilepsy & Functional neurosurgery
COMPARATIVE DISCIPLINES
Comparison between specialties:
Neurosurgery is to Neurology as Cardiac Surgery is to Cardiology.
COMMON NEUROLOGICAL CONDITIONS
Neurology Conditions:
Neurodegenerative diseases, neurodevelopmental disorders, autoimmune conditions, headaches/migraines.
Neurosurgery Conditions:
Hydrocephalus, tumors, trauma, vascular malformations, degenerative spine disease, stroke, epilepsy, movement disorders.
OBJECTIVES OF NEUROSURGERY
Key skills include:
Identify pathologic processes that may require or benefit from neurological surgery.
Recognize neurosurgical emergencies.
CENTRAL NERVOUS SYSTEM (CNS) & HEALING
Healing Limits:
The brain has limited healing capacity; typically does not regenerate new neurons.
Healing primarily occurs through neuroplasticity, reallocating redundant pathways.
Injury Types:
Primary Injury: Direct impact from a pathological process.
Secondary Injury: Effects following primary injury, can instigate further damage (e.g., hypoxia/ischemia, cerebral edema).
Complications include:
Mass effect
Raised intracranial pressure
CEREBROSPINAL FLUID (CSF) FACTS
CSF Composition:
Represents 10% of intracranial volume (according to Monro-Kellie doctrine).
Primary compensatory mechanism for intracranial pressure (ICP).
Volume Estimates:
Neonates: 40-60 mL
Children: 65-140 mL
Adults: 130-150 mL
CSF Production:
Total daily production: ~ 500 mL, with a turnover rate of 3.7 times/day.
85% of CSF resides in the subarachnoid space, 15% in the ventricles.
Require ICP > 6.8 mmH2O to cross arachnoid villi for absorption.
MONRO-KELLIE DOCTRINE
Concept:
The skull is a fixed space; if one component increases (i.e., blood, CSF, brain), others must decrease or ICP will rise.
RAISED INTRACRANIAL PRESSURE (ICP)
Symptoms include:
Headache, vomiting, lethargy/stupor, irritability.
Cushing’s Triad Indicators:
Hypertension
Bradycardia
Abnormal respiration patterns.
Brain’s physiological response aimed at sustaining its blood supply under pressure is countered by reduced heart rate.
CLASSIFICATIONS OF NEUROSURGICAL DISEASE
Categories:
Congenital
Neoplastic
Trauma
Vascular
Infectious
Functional
Degenerative
CONGENITAL CONDITIONS
Hydrocephalus:
Condition requiring medical and/or surgical intervention.
Surgical treatments include:
Ventricular shunt, endoscopic third ventriculostomy (ETV), external ventricular drain.
Hydranencephaly:
Characterized by lack of brain development; brainstem and cerebellum present without cerebrum.
Detection occurs between 6-18 months of age.
NEURAL TUBE DEFECTS
Types:
Anencephaly
Encephalocele
Spina bifida, including variations.
Etiology includes genetic factors and folate deficiency.
CRANIOSYNOSTOSIS
Condition: Early fusion of cranial sutures, primarily the sagittal suture (most common).
Surgical corrections involve vault reconstruction for skull deformities.
TRAUMA EVALUATION
Head injury assessment should include:
Glasgow Coma Score (GCS), pupillary response, eye movements, motor power, sensory testing, abnormal postures, and more.
GLASGOW COMA SCALE:
Components include eye opening, motor function, and verbal response. Scores range from 3 (unresponsive) to 15 (fully alert).
Determining changes in GCS:
Decrease in GCS by 2 points is significant.
Recognition of new pupillary abnormalities or focal deficits also indicates clinical deterioration.
HEMATOMAS CLASSIFICATION
Epidural Hematoma:
Located between the skull and dura mater; associated with arterial injury (middle meningeal artery).
Emergency condition; symptoms may present as a lucid interval followed by rapid decline.
Subdural Hematoma:
Found immediately under the dura; results from tearing bridging veins.
Can be acute, subacute, or chronic depending on time frame post-injury.
Intracerebral Hematoma:
Introduces space-occupying lesions within the brain. Typically does not need intervention unless significant edema arises.
GUNSHOT WOUNDS & TRAUMA MANAGEMENT
Gunshot wounds lead to significant damage, often resulting in severe mortality rates.
Management involves rapid assessment and surgical intervention where appropriate.
SURGICAL TECHNIQUES AND INTERVENTIONS
Approaches may involve stereotactic radiosurgery to precisely target tumors or injuries without extensive resection.
Surgical options include:
Biopsy/resection, chemotherapy, radiation therapy for CNS tumors.
EPILEPSY SURGERY
Medically intractable seizures may warrant surgical options such as:
Anterior temporal lobectomy
Hemispherotomy
Corpus callosotomy
Responsive Neurostimulation is a newer method for managing seizures through real-time detection and intervention.
INFECTIONS IN NEUROLOGY
Subdural Empyema:
Infection that spreads through venous pathways from sinusitis or otitis, requiring urgent surgical washout and antibiotic therapy.
Cerebral Abscess:
Often secondary to infections like endocarditis or sinusitis, may require drainage if size exceeds 3 cm or adjacent to ventricles.
DEGENERATIVE SPINE DISEASE
Degenerative issues like spondylosis, stenosis, and herniated disks are prevalent within the population.
Surgical interventions occur when conservative management fails.
PERIPHERAL NERVE SURGERY
Management of compressive neuropathies, peripheral nerve tumors, and trauma includes surgical repair and rehabilitation for optimal patient outcomes.