Test 2 Flashcards
(179 cards)
1
Q
Neurosurgery
A
- Neurosurgery is one of the most complex, diverse, and challenging specialties
- Neurosurgical procedures include those on the
- Cranium
- Spine
- Brain
- Peripheral nerves
2
Q
Nervous System Divisions
A
- Central nervous system
- Brain
- Spinal cord
- Peripheral nervous system
- Cranial and spinal nerves
- Voluntary system
- Involuntary (autonomic) system
3
Q
Nervous System Tissue
A
- Neurons–are nerve cells that transmit nerve signals to and from the brain at up to 200 mph.
- Cell Body (soma)
- Dendrites-signal receivers
- Axons-which conduct the nerve signal
- Communicates with other cells at synapses–At the other end of the axon, the axon terminals transmit the electro-chemical signal across a synapse (the gap between the axon terminal and the receiving cell)
- Neuroglial cells–Glial cells make up 90 percent of the brain’s cells. Glial cells are nerve cells that don’t carry nerve impulses. The various glial (meaning “glue”) cells perform many important functions, including: digestion of parts of dead neurons, manufacturing myelin for neurons, providing physical and nutritional support for neurons
- Astrocytes
- form a layer around the capillary endothelial cells in the brain blood vessels
- Oligodendrocytes
- Ependymal cells
- Microglia
- Shwann cells
- satelite cells
- Astrocytes
- Cell Body (soma)
- Substances must move through the endothelial cell membranes, (mostly Lipids)
- Glucose, primary source of metabolic energy for neurons and glial cells
4
Q
Levels of Consciousness
Neurological Assessment
A
- Alert
- Patient is awake, responds immediately and appropriately to all verbal stimuli
- Lethargic
- patient is drowsy and inattentive but arouses easily; frequently drops off to sleep; cooperative when awake. IS ORIENTATED TO person, place, time.
- Stuporous
- Patient spends much of the time sleeping. He arouses with great difficulty and cooperates minimally when stimulated. Inappropriate responses to verbal commands are evident
- Semi-Comatose
- the patient has lost his ability to respond to verbal stimuli. There is some response to painful stimuli. Little motor function is seen. When the patient is stimulated with pain, non purposeful reflex motor activity is seen
- Comatose
- when the patient is stimulated, there is no response to verbal or painful stimuli. No motor activity is seen.
Talk to the Family to help with assessment
- when the patient is stimulated, there is no response to verbal or painful stimuli. No motor activity is seen.
5
Q
Brain and Adjacent Structures
A
- Scalp–extracranial arteries and portions of the dura mater are the only pain sensitive structures that cover the brain. The brain itself is insensate
- Skin- thick
- Subcutaneous–very dense tough and vascular is attached to the galea
- Galea–most of the blood supply is superficial to the galea. The subgaleal space is loose areolar tissue that allows mobility of the scalp. This is the plane that the standard craniotomy flap is created. Aponeurosis or Galea is similar to the fascia layer
- Periosteum–pericranium or periosteum separates the galea from the cranium. need elevators to scrape this
- Skull– flat bone, to open need Burr holes, high speed drill using a perforator and a cranitome to extent the burr holes and make a flap; where flap is placed depends upon where it is needed
Brain in a Box no relief from swelling increased ICP; sometimes the need for ventricularostomy to drain fluid or VP shunt
For a child the sutures of the cranial bones are open- Protection
- Formed by 28 bones, mostly flat bones
- Foramen magnum- where spinal cord leaves skull
6
Q
Three membranes that provide support and protection for the brain
A
- Meninges
- Dura mater—superficial
- tough, shiny fibrous membrane . Several arteries also lie within the layers of the dura. Largest is the middle meningeal (serious epidural hemorrhage)
- must close this layer usually with a 4-0 Nuerolon
-
on a TF needle usually pop offs but can be a swedged on
Several arteries lie within the layers of the dura, middle meningeal, epidural hemorrhage if torn.
- Arachnoid mater—middle
- transparent membrane, space between the dura is subdural space. Space between the pia mater is the subarachnoid space this space is filled with CSF. CSF is reabsorbed. Arachnoid matter is continous with the brain
- Pia mater—deep
- innermost layer follows the contours of the brain into the sulci and fissures. Has a rich vascular network, that projects into the ventricles to form the choroid plexus of the ventricles which produce CSF
- The volume of the cranial cavity is fixed, rigid, hemorrhage and swelling in the brain is critical “In a Box”
- Dura mater—superficial
7
Q
Divisions of the brain:
A
- Forebrain: (Prosencephalon)–Function-chewing, equilibrium, vision, facial sensation, intelligence, memory, personality, respiration, smell, taste
- Diencephalon- hypothalamus, thalamus, pineal gland Directing sense impulses throughout the body. Autonomic function, endocrine function, motor. Function, homeostasis, hearing, vision, smell, taste
- Telencephalon (cerebrum)- cerebral cortex, basal ganglia, Olfactory bulb,
- Midbrain: (Mesencephalon) Function- responses to sight, eye movement pupil dilation, body movement, hearing
- Hindbrain: Function-Attention, sleep, autonomic functions, complex, Muscle movement, conduction pathway for nerve tracts, Reflex movement, simple learning
- Metencephalon-Function-arousal, balance, cardiac reflexes, circulation, fine muscle movement sleep. Pons-relay center, regulate breathing. Cerebellum-coordination of voluntary movement, Balance, equilibrium
- Myelencephalon-Function-automonic functions, breathing, pathway for nerve tracts, digestion, heart rate, swallowing, sneezing. Medulla oblongata
8
Q
Cerebrum
A
- Divided into Right and Left are the largest parts of the brain.
- Each hemisphere is divided into frontal, parietal, occipital, and temporal lobes.
- Separated by the longitudinal fissure and the falix cerebri, but remain connected underneath the falix by a bundle of nerve fibers called the corpus callosum
9
Q
Lobes of the brain
A
- Frontal
- Parietal
- Temporal
- Occipital
- These are anatomic landmarks used in surgical procedures
- lateral sulcus or Sylvian fissure, divides the temporal lobe from the frontal and parietal lobes.
- Central Sulcus or Fissure of Rolando, separates the frontal from the parietal lobe also separates the motor cortex from the Sensory cortex.
10
Q
Frontal Lobe
A
- Lies anterior to the central sulcus
- Houses functions of:
- Intellect
- Abstract reasoning
- Movement
- Language
- Personality
- Making decisions
- Thinking studying
- Planning
- Speaking fluently and meaningful
- Phineas Gage a railroad worker survived and accident where a large iron spike was driven into his frontal lobe With a huge personality change
11
Q
Parietal lobe
A
- posterior to the central sulcus extending back to the parietoccipital fissure,final receiving and integrating station for sensory impulses, Pain, Touch from the contralateral side of the body, object identification
- Processes sensory information
- Taste temperature and touch
12
Q
Occipital lobe
A
- lies posterior to the parietooccipital fissure—receives and integrates visual impulses and registers them as meaningful images
- Have to process images very fast to send info to make sense of visual information so we are able to understand
13
Q
Temporal lobe
A
- inferior to the lateral sulcus (Sylvian fissure), involved with memory, speech, and smell. – lesions of this may affect both the right handed and left handed persons comprehension and verbalization of works—aphasia.
- Responsible for processing auditory information from the ears
- Comprehend or understand meaningful speech
14
Q
The convoluted surface of the cerebrum consists of
A
- gray matter (cerebral cortex)– thinking matter
- White matter
- Gyri (convolutions)- bumps
- Sulci (intervening furrows)- crevacises
15
Q
Lesions of the frontal area
A
- May have normal intelligence and memory, but may have a totally changed personality.
- Short temper, irritability, poor impulse control, sociopathic
- Communication abilities may change
- psychiatric disorders. profound alterations of behavior and personality, but basic cognitive , such as memory, language visual-spatial function, motor and sensory functions are normal.
- Bilateral lesions produce a reduction or cessation of behavior, may sit and stare passively not speaking or responding
- “pseudodepressed”
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Q
Lesions of the parietal lobe
A
- left inferior parietal lobule–Agraphia, acalculia, right-left confusion, and finger agnosia
- right inferior parietal lobe lesions – neglect of the left side of the body
- The superior parts of the parietal cortex are to visuospatial, and constructional functions such as stereognosis (shapes), graphesthesia (recognize letters or numbers drawn on the skin
- Lesions of the right parietal lobe produce important neurobehavioral deficits, – left sided neglect, denial of the presence of a motor deficit (anosognosia) and dressing apraxia(inability to place garments correctly in relation to body
- Right parietal, difficulty finding ones way around, cannot draw or read a map.
- Speech and language are good in patients with right parietal lesions,the emotional intonation of speech may be lacking, and cannot comprehend emotional tone of others. Do not recoginize sarcasm or humor.
- These are disabling to patients in the social world.—difficult for families to accept
17
Q
Lesions of the Temporal Lobe
A
- Inability to recognize non-verbal sounds.
- Auditory agnosia
- Left superior gyrus contains wernicke’s area
Lesions can cause deafness. Bilateral can cause pure word deafness (inability to understand spoken word - Wernicke’s area critical to the comprehension of auditory language.
“slient area” surgical resection of the area produces only very subtle deficits.
Musical qualities may be affected by right temporal, and non verbal memory.
Medial Temporal areas—hippocampus, related to memory
Bilateral lesions—loss of new learning and recent memory.
Unilateral left medial verbal memory, right produce nonverbal memory loss.
Acute lesions (strokes) may cause confusion or delirium
18
Q
2 types of Aphasia
A
- Broca’s aphasia:
- Non glurny, halting, dysarthric, and agrammatic speech.
- Meaning conveyed by meaning carrying nouns and verbs, leaving out the minor grammatical words.
- Reading is halting and reduced in fluency.
- Affected more than auditory comprehension.
- Most have right hemiparesis (paralysis of right arm and leg)
- spell poorly
- Lesions involve the left frontal region.
- Wernicke’s Aphasia
- Speak fluently and effortlessly, meaning is obscured by the meaningful mouns and verbs.
- Auditory comprehension is usually severely impaired.
- Cannot answer yes no questions
- writing is abnormal.
- Have no hemiparesis and write but the content is abnormal and spelling is abnormal.
- Lesions=- posterior 2/3 of left superior temporal gyrus. Impairment of comprehension.
Broca’s area is the motor speech area and it helps in movements required to produce speech. When there is an issue in this area, a patient can understand the speech of others, but can’t produce any speech him or her self. This is called Broca’s aphasia. Wernicke’s area, which is located in the parietal and temporal lobe, is the sensory area. It helps in understanding speech and using the correct words to express our thoughts. When there is an issue in this area, a patient may be able to produce speech, but cannot understand the speech of others.
19
Q
Lesions of the Occipital Lobe
A
- The posterior poles of the occipital lobes are the primary visual cortices
- Damage to one side produces a contralateral hemianopic visual field defect for both eyes
- Damage to both sides may produce cortical blindness–some pt are unaware of blindness and confabulate descriptions of objects and scenes they claim to see.
- Adjacent occipital areas – visual association cortex.
- Lesions –visual agnosia-can see but cannot recognize or interpret visual information
20
Q
Limbic System
A
- The limbic system is a network of structures located beneath the cerebral cortex. This system is important because it controls some behaviors that are essential to the life of all mammals (finding food, self-preservation)
- Large parts of the cortex near the medial wall of the cerebral hemisphere
- Hippocampus
- Amygdala
- Septum
- Affects endocrine and autonomic functions of the body, recent memory, emotions, behavior, motivation, and mood states
21
Q
Sensory and Emotion
(limbic system)
A
- amygdala, a small almond-shaped structure deep inside the brain. important for making associations across stimulus modalities (a certain fragrance often elicits an associated visual image).
It appears to be responsible for the influence of emotional states on sensory inputs. This produces a spectrum of sensory perceptions from apparently identical stimuli (ex. the sound of one’s own motorcycle is never perceived as noise). Thought to be responsible for face recognition. These connections enable it to play an important role in the mediation and control of major activities like friendship, love and affection and on the expression of mood. Also how we react to stimuli, such as fear - hippocampus, a tiny, seahorse-shaped structure, seem to be the main areas involved with memory emotional responses
- hypothalamus, particularly its median part, has been identified as a major contributor to the production of loud, uncontrollable laughter. sits under the thalamus at the top of the brainstem. Although the hypothalamus is small, it controls many critical bodily functions: Controls autonomic nervous system Center for emotional response and behavior Regulates body temperature Regulates food intake Regulates water balance and thirst Controls sleep-wake cycles Controls endocrine system
- Thalamus, relays information from sensory receptors to the proper areas of the brain. “inner room” in Greek, as it sits deep in the brain at the top of the brainstem. The thalamus is called the gateway to the cerebral cortex, as nearly all sensory inputs pass through it to the higher levels of the brain.
22
Q
Diencephalon
A
- Part of the forebrain
- Thalamus
- All sensory information is transferred through the thalamus
- Perception of body sensations
- Hypothalamus—autonomic regulation of the body
internal environment and connected to the pituitary gland - Controls fluid and electrolyte, appetite, reproduction, thermoregulation immune response, and emotional response.
- Attention and consciousness.
- Hypothalamus—autonomic regulation of the body
23
Q
Hypothalamus
A
- Above the pituitary gland and below the thalamus
- Responsible for hunger and thirst and the maintenance of body temperature
- Also controls the pituitary gland (master gland) which controls all other endocrine glands in the body
24
Q
Brainstem
A
- Vital cardiovascular and respiratory regulation; Autonomic Functions
Located in posterior fossa - Damage to the brainstem is often devastating and life-threatening because it can affect movement, senses, consciousness, perception and cognition
- Forms floor of the fourth ventricle
- Mesencephalon (midbrain)
- Pons
- Medulla oblongata
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Cerebellum
* Occupies the posterior fossa
* Forms the roof of the fourth ventricle
* Two lateral lobes and a medial portion
* **Principally concerned with balance and coordination of movement**
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Pathologic Lesions of the Brain
* Brain tumors are malignant or benign
* Primary tumors (arise from brain tissue) do not resemble the carcinomas and sarcomas found in the body
* WHO systems lists more that 120 types of brain tumors
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Primary brain tumors
* Metastatic brain tumors are much more common in adults.
* Primary malignant brain tumors are the second most common cause of cancer death in children up to 15 years old.
* The second most common cause of cancer death in people ages 15-34
* Most common for children– astrocytoma, medulloblastoma, ependymoma,
* Most common for adults–metastatic from lung, breast, melanoma, glioblastoma multiforme, anaplastic astrocytoma, meningioma
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Brain Tumors
* Primary Brain Tumors
* Intracranial tumors originating of CNS tissue(neuroglia tumors[gliomas])
* Benign brain tumors
* Intracranial tumors that originate in the skull cavity but are not derived from the brain tissue. (meninges, pituitary gland, pineal gland)
* Metastatic brain tumors
* Metastatic tumors start elsewhere in the body and spread to the brain.
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How is Brain Cancer Treated?
* Brain cancer treatment usually involves biopsy and resection of as much tumour as possible. This is generally followed by a combination of radiotherapy, chemotherapy and glucocorticoid treatment.
* Further treatment is targeted at the symptoms that are encountered. Commonly this includes anticonvulsants (for seizure activity), antinauseants (for nausea and vomiting), analgesics (for pain), dexamethasone (reduces swelling surrounding tumour and improves neurological function), seizures and heparin prevent deep vein thrombosis
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Intracranial tumors
* originate in the skull cavity but are not derived from the brain tissue. (meninges, pituitary gland, pineal gland)
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Tumors of intraepithelial tissue
* Include gliomas, tumors that are from neurolgial cells
* Astrocytomas
* **Most common of all primary tumors**
* **Glioblastoma multiforme (GBM)**
* occur in the cerebellum of children and the cerebrum of adults, often cystic and discrete in children and infiltrating and not well defined in adults
* Oligodendroglioma
* Found in the cerebral hemispheres, infiltrating
* tx is usually surgery, then radiation and then chemotherapy
* Ependymoma
* Children, usually in or near the ventricular walls
* 4th ventricular wall – metastasizes into the subarachnoid space, surgery followed by radiation, 5 year survival rate is 73%
* Medulloblastoma
* Fast growing, recurring tumor in young children
* **Most common malignant pediatric brain tumor**
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More tumors
* Tumors of the meninges
* Meningiomas, common in 40-50 & 60 Yr
* Usually benign, slow growing tumor with attachment to the dura
* Can be very vascular and a challenge to remove
* Tumors of the cranial nerves
* Benign, slow growing
* Vestibular schwannomas
* Tumors of the sellar region
* Pituitary adenomas
* Endoscopic transsphenoidal hypophysectomy
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Pituitary Tumors
* The pituitary gland is located in the pituitary fossa of the sphenoid bone **(sella turcica)**, which lies directly below the optic nerve.
* Enlargement of the pituitary gland causes erosion of the surrounding bone.
* Symptoms include headaches, visual field defects (compression of the optic nerve), palsies of cranial nerves III, IV, and VI.
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Pituitary Problems
* Acromegaly—occurs in adulthood or after the epiphyses of the long bones have fused. Excess Growth Hormone
* Gigantism—occurs before puberty and the fusion of the epiphyses plate. Excess Growth Hormone
* Cushing’s Syndrome—excessive production of ACTH (adrenocorticotropin)
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Neuroendoscopy
* Minimally invasive
* Minimal tissue trauma
* Also may need to convert to open procedure
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Transsphenoidal Approach
* Access to the Pituitary fossa (sella tursica)
* Less invasive, some patients go home the next day
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Ventricular System and Cerebrospinal Fluid
* Four communicating cavities called ventricles that are filled with CSF
* Lower medial portion of each cerebral hemisphere
* Lateral ventricle (wishbone)
* Each lateral ventricle has a body and three horns; frontal, occipital and temporal.
* Below is the third ventricle it communicates with the lateral ventricles through the foramen of Monro and with the fourth ventricle through the aqueduct of Sylvius
* Fourth ventricle is between the cerebellum and the brainstem, roof of the ventricle is the foramen of Magendie which opens into the cisterna magna. Lateral-foramina of Luschka opens into cisterns (reservoirs)
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Cerebrospinal Fluid
* Much of the CSF originates in the choroid plexuses of the ventricles
* It bathes the brain and spinal cord
* Helps support the weight of the brain
* Acts as a cushion for the brain and spinal cord
* Total average amount of CSF circulating is 150ml (adult)
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Pathologic conditions related to CSF:
* Lumbar puncture
* Clear and colorless
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Hydrocephalus
* Noncommunicating (obstructive)
* Involves an obstruction of CSF pathways
* Communicating
* Abnormality in CSF absorption with increased ICP
* Normal-pressure
* Most common in the elderly, abnormal CSF absorption
* **an abnormal increase in CSF volume within any part or all of the ventricular system**
* **Treatment is VP shunt (Ventriculoperitoneal Shunt)**
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**The flow of CSF**
* Forms from the blood in the Choroid plexuses
* Intraventricular foramen (foramen of Monro)
* Flows to the third ventricle
* Cerebral aqueduct (aqueduct of sylvius)
* Into the fourth ventricle
* Exits through two lateral aperture, one medial aperture (Luschke, megendie)
* Through the cerebellomedullary cistern and down the spinal cord and over the cerebral hemispheres
* Reabsorbed in the Superior arachnoid villi
* \*Ventricles hold about 25ml
Remaining circulates in the cranial and spinal space secreted at a rate of 450ml/24 hr. in an adult recirculated 3 times each day
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**Blood Brain Barrier**
* German bacteriologist Paul Ehrlich found that if he injected animals with blue dye that tissues through out the whole body would turn blue, except in the brain and spinal cord.
* Endothelial cells form the walls of capillaries. In the brain there is a different arrangement they join up at junctions to block the passage of most things.
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Protectors of the Brain
* **The Blood brain barrier (BBB) a protective mechanism within the brain’s capillaries that helps to maintain a stable environment for the brain**
* It is a selective barrier allowing such substances glucose, essential amino acids, some electrolytes, O2, Co2 etc. to pass through the brain capillary system easily while inhibiting toxic substances such as certain drugs, urea, creatinine, and other blood borne metabolic wastes
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Blood transports
* Oxygen, nutrients and other substances necessary
* Needs for oxygen and glucose are critical
* Constant flow of blood to the brain must be maintained or brain tissue will die
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Cerebral Blood Supply
* Brain requires 20% more oxygen than any other organ to maintain a high level of metabolic activity
* Brain uses oxygen in the metabolism of glucose the chief source of energy
* Without out O2 survival time is very short
* Cns function is compromised with out blood gloucose and unconsciousness results
* **Arterial supply to the brain**
* **Internal carotid arteries anteriorly**
* **Vertebral arteries posteriorly**
* **Circle of Willis**
* **Ensures continuity of the circulation if any one of the four main channels are interrupted**
* **The brainstem and cerebellum are supplied by branches of the basilar and vertebral arteries.**
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Cerebral Blood Supply
* Main branches for distribution of blood to each hemisphere of the brain from the internal carotid arteries are the anterior and middle cerebral arteries
* Anterior cerebral artery—anterior two thirds of the medial surface of hemisphere, including half of the frontal, parietal and temporal lobes
* Posterior cerebral artery—originates at the basilar artery and supplies the occipital lobe and remaining half of the temporal lobe, on the inferior and medial surfaces
* The cerebral veins do not parallel the arteries as in most other parts of the body
* Anastomoses in the pia mater form larger cerebral veins, cross the subdural space, empty into the great dural venous sinuses
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Brain Trauma
Skull Fractures
* Simple skull fractures
* depends on the degree of brain injury, simple skull fractures can be serious if they cross major vascular channels –causing a subdural or epidural hematoma
* Depressed skull fractures
* require a surgical procedure to elevate the depressed bone
* Open skull fractures
* should be irrigated copiously and closed to prevent infection
* Deformities
* Craniosynostosis is most common pedi deformity seen, caused by a premature closure or lack of formation of cranial sutures, usually repaired during the first year (brain capacity triples!!)
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Brain Trauma
| (Hemmorrage)
* Subdural hemorrhage
* Epidural hemorrhage—lacerations of the middle meningeal artery-branch of the external carotid supplies the dura mater results from a tear in an artery, (middle meningeal) located under the temporal bone. Bleeding is arterial, rapid compression of the brain occurs. More common in young because the Dura is not so firmly attached to the skull. Presents with a history of head injury and a brief period of unconsciousness, followed by lucid period (consciousness regained) followed by rapid progression to unconsciousness. Increased ICP herniation
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Subdural Hematoma
* Between the Dura and the arachnoid space
* Acute –symptoms seen within 24 hours of injury
* Chronic—symptoms may not bee seen for several weeks
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Epidural Hematoma
* **usually caused by head injury with a skull fracture. Between the bone of the skull and the Dura.**
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Intracranial hematoma
* Occurs in the brain tissue
* Blood often leaks into the CSF
* Usually elderly persons, and alcoholics. (friable vessels)
* Can occur in any lobe of the brain, most common in frontal or temporal.
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Transient Ischemic Attacks (TIA’s)
* is characterized by a focal ischemic cerebral neurologic deficit that lasts less than 24 hours (usually less than 1-2 hours).
* Equivalent to “brain angina”, temporary disturbance in focal cerebral blood flow, which reverses before infarction occurs.
* The causes are same as ischemic stroke and include atherosclerotic disease of vessels and emboli. May provide warning of impending stroke.
* Symptoms of stroke/TIA always are sudden in onset and focal and are usually one-sided. The most common symptom is unilateral weakness of the face and arm or leg.
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Cerebrovascular Accidents (CVA’s)
* CVA– Stroke Remains one of the leading causes of mortality and morbidity in the US (600,000 approximately 167,000 of these die.)
Acute focal neurologic deficit from an interruption of blood flow in a cerebral vessel (ischemic stroke the most common type) due to thrombi or emboli or to bleeding into the brain tissue ( hemorrhagic stroke)
* Thrombolic– common sites of plaque formation include larger vessels of the brain. The origins of the internal carotid and vertebral arteries, and junctions of the basilar and vertebral arteries. These infarcts often affect the cortex, causing aphasia, hemi neglect syndrome (patients fail to be aware of items to one side of space.), visual field defects, or transient mononuclear blindness (Peripheral blindness). Seen in older persons with PAD, not associated with activity and may occur in a person at rest.
* Embolic– caused by a moving blood clot that travels to the brain. (rheumatic heart disease, atrial fib. Recent MI, bacterial endocarditis) most originate from thrombus in the left heart, they also may originate in an atherosclerotic plaque in the carotid arteries. Affects the larger proximal cerebral vessels, lodging at bifurcations. Most common site is the middle cerebral artery. Sudden on set with immediate maximum deficit.
* Hemorrhagic—most frequently fatal stroke is a spontaneous hemorrhage into the brain, edema, compression of the brain contents, age and hypertension. Causes aneurysm, trauma, arteriovenous malformations, drugs. Occurs suddenly usually when the person is active. Vomiting commonly occurs at the onset, and HA. Hemorrhage into the basal ganglia results in contra lateral hemiplegia, progresses rapidly to coma, death
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Vascular pathologic conditions of the brain
* Aneurysms
* Broad neck
* Aneurysmal clipping
* Small neck
* coils
* Vascular malformations
* Arteriovenous malformations (AVM’s
* Classified as acute or chronic, based on time intervals before the appearance of symptoms.
* Acute progresses rapidly and has the highest mortality rate because of the severe secondary injuries, increased ICP Edema
* Chronic usually after a head injury, but not for several weeks, and they have forgotten that they had an injury (older persons) blood seeping into subdural space is not absorbed it becomes encapsulated.
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Aneurysm Coiling
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Aneurysm
* May expose the carotid artery to have control in case of bleed
* Clips and appliers must match
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A-V malformation
* Bridging vein bleed, but arterial
* An abnormal connection between arteries and veins
* Can need surgery; or not if stable
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Pathological Conditions Related to the Cranial Nerves
* Tic Douloureux
* “Trigeminal Neuralgia”
* Bell’s Palsy
* Affects the 7th cranial nerve (facial nerve)
* Menier’s Disease
* Related to the 8th cranial nerve (vestibulocochlear nerve)
* Acoustic Neuroma
* A benign tumor of the 8th cranial nerve (vestibulocochlear nerve)
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Tic Douloureux:
* “Trigeminal Neuralgia”
* significant irritation of the 5th cranial nerve (mainly the maxillary or mandibular branch of the trigeminal nerve) results in facial tics, facial grimacing, and excruciating, stabbing pain to the side of the face; most effectively treated with anti-seizure medication; neuralgia can become progressively worse with time’ surgical release of scar or nerve tissue eliminates symptoms in severe cases.
* Stabbing pain in parts of the face can occur on both sides of the face but not at the same time
* 5th cranial nerve
* Episodes can last for days, weeks, or months
* Occurs most often in people over the age of 50 , more common in women than men
* Anticonvulsant medications are used to block nerve firing
* Rhizotomy – select nerve fibers are destroyed to block pain, causes some sensory loss and facial numbness
* Surgeon must take great care to not injure the pons or the facial nerve
When the risk of surgery is high because of other medical problems, or where the patient simply refuses surgery, the "gamma knife" procedure may be used. This is a method of irradiating the tumor, invented by Lars Leksell in 1971. This procedure avoids surgery with its attendant risks. In the past, this option was usually recommended only for higher risk surgical cases because of the possibilities of late radiation complications, and the need for ongoing MRI monitoring of the results of the procedure.
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Bells Palsy
* Affects the 7th cranial nerve (facial nerve)
* results in unilateral facial paralysis of sudden onset; cause unknown; involves swelling of the facial nerve perhaps due to an immune or viral disease; treated with corticosteroids; partial paralysis typically resolves after several months.
* Causes: inflammation of the 7th cranial nerve (herpes zoster, HIV, middle ear infection)
* Sometimes have a cold before the symptoms begin
* Start suddenly, usually on one side of the face
* Difficulty closing one eye
* Drooling lack of control over the muscles
* Drooping of the face
* No treatment may take weeks or months for the muscles to get stronger
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Meniers disease
* Related to the 8th cranial nerve (vestibulocochlear nerve)
* a recurrent and usually progressive group of symptoms including: ringing in the ears, dizziness, and a sensation of fullness or pressure in the ears; cause unknown but swelling of the membranous labyrinth has been found; treatment consists mainly of bed rest, antihistamines and motion sickness medication , cessation of smoking, and rarely surgery (transecting a portion of the nerve); progressive deafness can occur.
* Affliction of the 8th cranial nerve, usually progressive and recurrent.
* Dizziness and a sensation of fullness or pressure in the ears
* Vertigo can be disabling
* Can try dietary (low salt) and medications (diuretics)
* When vertigo becomes intractable, can use ototoxic medications to reduce the vestibular hair cells , and also dexamethasone.
* a section of the 8th cranial nerve may be removed.
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Acoustic Neuroma
* symptoms include hearing loss, balance disturbances, pain, headache, and tinnitus; treatment typically consists of surgical resection of the tumor (which can lead to facial paralysis along with permanent hearing loss).
* Also known as vestibular schwannoma
* Is the major surgical lesion of the 8th cranial nerve
* Usually a benign tumor, growing from the nerve sheath at its entrance into the internal auditory meatus
* Symptoms include unilateral deafness, tinnitus, unilateral impairment of cerebellar function, numbness of the face (involvement of 5th cranial nerve)
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Surgical Approaches to the Brain
* Burrholes
* Minimum exposure that can be made to access the brain
* Craniotomy—removal of a section of the cranium “bone flap”
* Craniectomy—removal of a section of the cranium –permanently
* Transsphenoidal Approach—route to the pituitary fossa through the nose or gingiva
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Evacuation of epidural or subdural hematoma
* After trauma decompression of the brain and removal of any hematomas that are above or beneath the dura mater may be required.
* Evacuation can be done through burr holes or a craniotomy
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Burr hole for evacuation of hematoma
* The burr or perforator bit is used on the drill of choice (TPS, Midas Rex)
* Surgeon makes at least two small incisions over the site of the lesion.
* If the hematoma is an epidural hematoma he will use copious amounts of irrigation to remove the clot
* If the hematoma is a subdural hematoma then the dura is incised and the clot is evacuated with irrigation
* A drain may be placed and if needed additional burr holes can be made as necessary
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Hydrocephalus
* Excessive accumulation of CSF and increased ICP
* VP shunt
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Cranial nerves
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Craniotomy
* The removal of a section of the cranium (bone flap)
* One or more burr holes are made
* Craniotome with a dura guard is used
* The bone flap is replaced at the end of the procedure
* Multiple types of incisions are used depending on the location of the pathology
* Frontal, Parietal, occipital, Temporal or combination
* Pterional is versatile approach to the anterior and middle fossae
* Access frontal or temporal lobes near the Sylvian fissure
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A craniotomy is done for:
* Intracranial hematomas
* Debulk tumors
* Clip vascular lesions
* Aspirate abscess
* Decompress cranial nerves
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Mayfeild
used for positioning head in a crani
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Craniotomy
Turning the “Flap”
* May peel the scalp off the pericranium
* With muscles (osteoplastic)
* Or strips the periosteum off the skull before the “Flap” is turned
* Flap is placed in antibiotic solution and is placed in a SAFE PLACE on table, always part of Report
* May be sent to lab or placed in abdomen
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Craniectomy
* Permanent removal of a section of the cranium
* Maybe repaired with titanium mesh
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Suture & Dressings
* Dura must always be closed- 4-0 Neurolon TF
* Vicryl- 2-0 CP2
* Nylon, staples
* Dressings for a head procedure may be just a wrap.
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Spinal Column
* Small holes in the cervical vertebrae for the vertebral artery
* Protection for the spinal cord and spinal nerves
* Attachments for ligaments tendons muscles
* Structural support for head shoulders chest, connects upper and lower body, balance and weight distribution
* Flexibility and mobility flexion extension side bending rotation
* Bone produce rbc’s
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Spinal Anatomy
* The vertebral column was designed to provide bony protection for the spinal cord and the 31 pair of spinal nerves coming off of the spinal cord.
* **There are:**
* **7 cervical vertebrae**
* **12 thoracic vertebrae**
* **5 lumbar vertebrae**
* **5 fused sacral vertebra**
* **1 coccyx (tailbone)**
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Lordosis and Kyphosis
* We begin with Kyphosis in the womb a C shape, then as we grow and muscles develop we begin walking. As we walk weight shifts to the spine and secondary curves develop in the cervical and lumbar regions
* These curves are important to balance, stress absorption and distribution.
* **Cervical is Lordosis**
* **Thoracic is kyphosis**
* **Lumbar is lordisis**
* **Sacral is kyphosis**
* **tailbone**
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Cervical Spine
C1-C7
* The cervical spine is divided into two parts, the upper region (C-1 and C-2)and the lower (C-3 through C-7)
* C-1 is also called the Atlas
* First cervical vertebra supports the skull; the atlas is a ring of bone made up of two lateral masses joined at the front by the anterior arch, and at the back by the posterior arch
* C-2 is called the Axis
* The axis is the second cervical vertebra. It is a blunt tooth-like process that projects upward. This provides a type of pivot and collar allowing the head and atlas to rotate around the axis
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Thoracic Vertebrae
T1-T12
* The thoracic vertebrae increase in size from T1 through T12. They are characterized by small pedicles, long spinous processes, and large intervertebral foramen (neural passageway) which results in less incidence of nerve compression.
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Lumbar Vertebrae
L1-L5
* The lumbar vertebrae graduate in size from L1 through L5. These vertebrae bear much of the body’s weight and related stress.
* The pedicles are longer and wider than the thoracic spine. The spinous processes are horizontal and more squared in shape.
* The intervertebral foramen are large but nerve root compression is more common than in the thoracic spine.
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Vertebral body
* Largest part of the vertebra. Oval shape, covered with strong cortical bone, with cancellous bone within.
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Intervertebral foramen
* The pedicles have a small notch on their upper surface and a deep notch on their bottom surface. When the vertebrae are stacked on top of each other the pedicle notches form an area called the intervertebral foramen. Nerve roots exit from the spinal cord through this area to the rest of the body
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Transverse process and Spinous process
* Serve as connection points for ligaments and tendons
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Laminae
* Two flat plates of bone that extend from the pedicles on either side and join in the midline
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Pedicles
* Two short processes, made of strong cortical bone, that protrude from the back of the vertebral body
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Intervertebral disc
* Between each vertebral body is a cushion called disc these absorb the stress and shock.
* Annulus fibrosis—tire like structure that encases a gel like center called the Nucleus Pulposus
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Ligaments and tendons of the spine
* help to provide structural stablity.
* Intrasegmental holds individual vertebrae together
* Intersegmental holds many vertebrae together
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The spinal cord proper is also lined
* with the same three meninges as the brain:
* dura mater
* Arachnoid mater
* pia mater
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Spinal Nerves
* At each vertebral level is a pair of spinal nerves, each has an anterior and posterior root.
* The anterior root (Motor root) contains cells the lie in the anterior horn of the spinal gray matter.
* The posterior root (Sensory root) contain cells that lie in the spinal ganglia located in the intervertebral foramina.
* After passing through the intervertebral foramen, a spinal nerve divides into several branches.
* These branches are know as rami.
* The ventral rami of spinal nerves form networks on both left and right sides of the body by joining with varying numbers of fibers from ventral rami of adjacent verves.
* This network is called a plexus. There are four plexus.
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Spinal blood supply
* The arterial blood supply to the spinal cord arises from the vertebral arteries and the anterior spinal artery and the posterior spinal arteries
* They branch and anastomose on both sides of the cord and within the cord
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Operative procedures can be done on and around the spine to:
* Correct congenital malformations
* Treat injuries
* Remove tumors
* Repair and remove herniated and degenerative disc
* Drain abscesses
* Treat intractable pain
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Pathologic lesions of the Spinal Cord
* Spine and spinal cord tumor
* Mostly metastatic
* Extradural
* Intradural
* Extramedullary
* intramedullary
* Spinal epidural abscess--from infection surgery. I & D with 4-8 weeks of IV Antibiotics therapy
* Disk disease-- most frequently encountered problem L4-L5, L5-S1 level is most common site.
* Intractable pain
* controlled by epidural opiates, patches, or medication pump, --posterior rhizotomy– asectioning the sensory roots or anterolateral cordotomy– incising the spinothalamic tracts that carry pain and temperature impulses also placement of electrodes in the epidural space. Laminectomy is necessaty for these
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Spina Bifida
* congenital failure of the union of the vertebral arches during fetal development which often produces fluid-filled, thin-walled sacs that protrude from the fetus back
* **Meningocele: dural sac filled with CSF found outside the body of the fetus**
* **Myelomeningocele: dural sac filled with CSF and spinal cord found outside the body of the fetus.**
* Causes—second most common birth defect, 1-out of every 1000. can occur anywhere along the spine
* Can be caused by medication (antiseizure) folic acid??
* Often diagnosed prenatally and is often seen with other CNS abnormalities, hydrocephalus, Chiari malformation of the hindbrain.
* Outcome depends on the type and the location.
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The prolapse of an intervertebral disc.
Three stages
1. the annulus fibrosis is often torn, but the nucleus has not extruded.
2. nucleus material forces through the tear and the posterior longitudinal ligament is stretched, but the nucleus extrusion has not yet reached the nerve.
3. The nucleus bulge protrudes further out and reaches the nerve which has to stretch over the growing bulk of the nucleus, this causes severe pain.
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Spondylolisthesis and Degenerative disc disease (DDD)
* most common problems that result in surgery.
* Spondylolisthesis is the forward slipping of one vertebra over the segment below it is usually L5 over S1
* Five classes
1. dispastic-dysplasia of the posterior articulations.
2. isthmic-stress fracture of the pars interarticularis.
3. traumatic
4. degenerative
5. pathological-local disease attenuates pedicule or pars.
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Spondylolisthesis
Spondyloloysis
Spondylosis
* Spondylolisthesis—forward subluxation of the lower lumbar vertebra on the sacrum
* Spondylolysis—breakdown of a vertebral structure (usually due to osteoporosis)
* Spondylosis—vertebral ankylosis (abnormal fixation, immobility, or fusion of a vertebral joint)
* \*\*\*Treatment for these injuries include pedicle screws, intervertebral fusions and rodding between the vertebrae
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Scoliosis
* Both children and adults can have scoliosis. Pediatric scoliosis or spinal deformity can be due to congenital abnormalities, neuromuscular diseases, or idiopathic causes.
* Congenital scoliosis can be secondary to failure of the embryonic spine to develop normally.
* Neuromuscular diseases such as polio, cerebral palsy, spin bifida, and muscular dystrophy are often associated with scoliosis.
* Idopathic scoliosis, as its name implies has no known cause. Subdivided into infant scoliosis 0-3 months, juvenile scoliosis 3-10 years, and adolescent scoliosis 10 years and up.
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Surgery of the spine
ACDF
* Anterior cervical decompression and fusion
* Treat disc herniation
* Spondylosis (degeneration)
* Pain in the neck, arms, hands, shoulders and weakness
* Performed to treat cervical disk herniation or cervical spondylosis
* Bone grafts used can be autograft or allograft.
* Awake intubation may be required if neck is unstable
* Supine with arms tucked, shoulder roll.
* Awake intubation if unstable
* Cervical injuries—placed in skeletal traction using using tongs applied to the skull. Can come to surgery with this on, great care is taken when moving and anesthesia may need to do an awake intubation.
* DDD is generally the cause of most cervical problems that involve surgery. When the disc height is reduced the foramen where the nerve exits is usually narrowed. This causes irritation to the nerve and is fixed by opening the foramen when the disc is removed.
* Spondylolisthesis can occur in the cervical spine, but trauma is usually the main cause.
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Laminectomy
* Removal of one or more of the vertebral laminae
* Done in the prone position (or lateral)
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Posterior lumbar fusion
* This procedure’s goal is to achieve bony fusion between two or more vertebral bodies. By laying bone between the transverse processes and the facet joints the fusion can take place. This procedure is often done with a laminectomy or discectomy.
* The surgeon may or may not use screws to fixtate the segments.
* Many surgeons use some type of fixation to account for the instability created with the laminectomy or disruption of the ligament and muscular structures
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Spinal Cord Stimulator
* Used to treat intractable pain
* Generates an electrical impulse to the epidural space
* Masks the pain by producing a tingling sensation
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Diagnostics
* X-rays—intraoperatively to verify
* CT scan—with or without contrast
* Standard for evaluation of acute head injury, first line screening
* MRI—radiofrequency pulses in a powerful magnetic field that gives high resolution images of the body with no known risk to patients and no radiation
* Is Gold standard for diagnosis of tumors, abscesses, injury and herniation
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Considerations
* Patient neurologic assessment
* Preparation for surgery
* Communication!!!
* Patient blood
* Diagnosis x-ray, neuromonitoring
* Surgical procedure
* Labs and diagnostic studies
* Surgical approach and position
* Special equipment, instruments, supplies
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Equipment
* Or bed—attachments positioning devices
* Jackson table, Andrews table, Wilson frame
* Skull clamps, pins, tongs
* Basic equipment— phelen table. Mayos, backtables
* SCD, ESU’s, bipolar, nitrogen, 2 suctions, cell saver,
* Microscope—
* Balanced, correct scope drape, cameras
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Minimally invasive and specialized neurosurgery techniques
* Microneurosurgery
* Use of the microscope restricts the surgeon’s field of vision and mobility
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Equipment
* Endoscopes—minimally invasive surgery
* X-ray, fluoroscopy c-arm or o-arm
* Sterotactic and image-guided—computer and instruments
* optical tracking device handheld device 3-d on screen while the surgeon is working
* Ultrasonic aspirator—CUSA
* Intraoperative monitoring—doppler, eeg
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Instrumentation, implants, and supplies
* Craniotomy set
* Laminectomy set
* Extra rep instruments, screws plates, cages
* Retractor sets
* Power instruments
* Microneuro-surgical instruments
* Transsphenoidal set, ENT set, Aneurysm set and clips, endoscopic equipment, CV set
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Hemostasis and visualization
* Scalp clips
* ESU, Monopolar
* Irrigation, suction (never suction a nerve!!!)
* Bone wax
* Cottonoids
* Gelfoam
* Thrombin
* Surgicel, fibrillar
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Anesthesia Concerns
* Anesthesia must communicate with Surgeon about the procedure, position, and Most Important the \* Patient!!
* IV, Central line, Arterial line,
* Drugs- antibiotics, steroids, diuretics
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Neuromonitoring
* EEG—view and record electrical activity
* EP—invoked potiental—response to visual auditory and sensory stimuli
* SSEPS—somatosensory evoked potentials, change can indicate surgical invasion of the site
* Lumbar and ventricular drains—allow for monitoring of ICP
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Drains
* For spinal surgery
* Foley catheters for monitoring urine
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Positioning
* Check with surgeon for correct position!
* Equipment
* Bed
* Sitting (Fowler’s)—air embolism
* Prone—always have the bed or stretcher available
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Draping
* Can be complex
* Towels may be sutured on, staples or may use blue impervious or 1010’s
* Three quarter drapes
* Equipment drapes (scope, c-arm etc..
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RANIEY SCALP CLIP APPLIER
| (bleeding control for edge of scalp)
117
RAINEY SCALP CLIPS
118
Automatic scalp clip applier
119
Aneurysm clip applier and clips
(open aneurysm repair, make sure these match)
120
mallet
121
strully scissors
122
Dural Scissors
123
Bipolar forceps
124
adson cranial rongeur
125
Leksell rongeur
126
Smith peterson rongeur
| (double action)
127
Kerrison Rongeur
128
Pituitary rongeur
129
Spurling
| (type of pituitary)
130
Peapod pituitary
131
#1 Penfield
| (cup)
132
#2 Penfield
| (little currette)
133
#3 Penfield
(looks like 2 but is really curved on disecting end)
134
Penfield 4
| (handle)
135
Penfield 5
136
Roton Micro Dissectors
137
Ball-ended dissector
138
Cobb Elevator
139
Langenbeck Elevator
140
Adson Elevator
141
Key elevator
142
Freer Elevator
143
Crile elevator
| (woodson)
144
Woodson Elevator
145
Cobb Curette
146
Ring Currette
147
Epstein Curettes
148
Scoville vs. epstein
149
Hudson Drill
150
Micro dissecting scissors
151
Dandy Clamp
152
Cup forceps
tumor forceps
153
Bayonet forcep
154
Brain Spatula
155
Nerve Hook Sharp
156
Taylor Nerve Hook
157
Love Nerve Root Retractor
158
* D'errico nerve root retractor
159
Adson- Beckman Retractor
160
Cerebellar Retractor
161
Greenberg Retractor
162
Meyerding Retractor
163
Scoville Retractor
164
Markham myerding retractor
165
Cervical retractor
166
Cervical distractor
167
Cloward hand held retractor
168
Myerding hand held retractor
169
Taylor retractor
have to anchor with tying gauze
170
Hibbs Retractor
171
Stille bone cutter
172
Horsley Bone Cutter
173
Stryker TPS
174
Midas Rex System
175
Wilson Frame
| (put on Jackson table)
176
semi- fowlers, fowlers
Captains Chair
worry about air embolism
177
Mayfield head frame
178
Phelan Table
179
CUSA
Cavitron Ultrasonic Suction Aspirator
