Chapter 24: Neurosurgery Flashcards
This instrument emits sound waves that penetrate the brain and bounce back to the machine to generate an image. It is used to locate lesions that lie deep beneath the surface of the cerebrum and evaluate the completeness of tumor resection.
Operative Ultrasound Machine
This device emits a variable ultrasonic energy field that emulsifies abnormal tissue while preserving normal neural tissue. Saline ejected from the tip of the handheld unit liquefies the tissue, which is then aspirated back to the unit. This instrument is used when a moderate to large amount of tissue is to be removed.
Cavitron Ultrasonic Aspirator (CUSA)
This positioning allows exposure of the frontal, parietal, and temporal lobes. A simple donut headrest is used for superficial tumor or clot removal, and a three-pin skull fixation system is needed for procedures that require complete immobilization of the head.
Supine
This positioning is used for exposure of the unilateral temporal lobe, occipital lobe, brain stem, or cerebellum.
Stabilization of the body requires a beanbag or chest rolls, tape, and pillows. The head may be placed onto a headrest
or into a fixation device, depending on the type of procedure.
Lateral or Semilateral
This positioning allows bilateral access to the occipital lobe, brain stem, or cerebellum.
It requires the use of a three-pin skull fixation device attached to a frame that attaches to the side rails of the head end of the operating table.
Sitting position
This positioning is used for bilateral access to the occipital lobe, cerebellum, or brain stem.
Chest rolls support the chest, and pillows are placed under the legs and feet. A Mayfield horseshoe headrest supports the patient’s head. A pin fixation device may also be used.
The Prone position
This procedure involves incising the cranium for access to the brain
Craniotomy
The cranium consists of eight bones; one being the _____ bone which forms the forehead, nasal cavity, and orbital roofs
Frontal bone
The cranium consists of eight bones; two being the _____ bones which form the side of the skull just posterior to the frontal bone, forming a large portion of the sides and roof of the cranium
Parietal Bones
The cranium consists of eight bones; one being the ____ bone which forms the back and large portion of the floor of the cranium.
Occipital
The cranium consists of eight bones; two being the _____ bones which form a small portion of the sides and floor of the cranium
Temporal bones
The cranium consists of eight bones; one being the _____ bone forming portions of the base of the cranium, sides of the skull, and base and sides of the orbits
Sphenoid
The cranium consists of eight bones; one being the _____ bone which forms portions of the roof and walls of the nasal cavity, the floor of the cranium, and the walls of the orbits
Ethmoid bone
Three layers of protective tissue called the cranial ____ cover the brain and spinal cord
List the three layers from outermost to innermost
Meninges
Dura Mater, Arachnoid, and Pia Mater
The Dura Mater is composed of what type of connective tissue?
Tough fibrous connective tissue
The arachnoid middle layer of the meninges is a _____ membrane
Serous
The layer closest to the brain is the pia mater; it contains _____ and _____ to provide nourishment to the neural tissue underneath.
Blood vessels and nerves
The space created between the arachnoid mater and the pia mater is referred to as the __________ space, an area that contains cerebral spinal fluid
Subarachnoid
The ______ represents the largest portion of the human brain.
Its surface is covered with convolutions (gyri), that are separated by shallow depressions (sulci) and deep grooves (fissures) into specific lobes
Cerebrum
The _____ is the second largest structure of the brain and is located posterior to the medulla oblongata and inferior to the
cerebrum’s occipital lobe.
The structure of this structure is similar to that of the cerebrum.
Cerebellum
The ____ ____ connects the brain to the spinal cord and consists of the midbrain, pons, and medulla oblongata
Brain Stem
The _____ __ _____ is a ring of arteries that gives rise to the various branches supplying blood to the brain.
Circle of Willis
The cranial nerves are 12 pair of nerves that, with the exception of the first and second, originate in the brain stem
They are responsible for ____ and ____ functions of the body
Sensory and Motor
An _____ hematoma may result from a fractured skull or blow to the head.
The pressure of blood from this arterial bleeding strips the dura away from the skull, causing more bleeding as the tiny veins from the dura to the skull are torn. There may be a symptomless period as the hematoma enlarges to a size sufficient to compress the cerebrum, resulting in a gradual loss of consciousness that can progress to coma and death without surgical intervention.
Craniotomy is performed to relieve the resultant pressure of the hematoma, as well as to debride the area and control bleeding.
Epidural hematoma
A _____ hematoma occurs in relation to severe head injuries. When veins bridging the cerebral cortex to the venous sinuses are torn or the cortex is lacerated, hemorrhage occurs.
Subdural hematoma
________ ________ (AVMs) are congenital defects causing abnormal communication between arteries and veins that divert blood from surrounding brain tissue.
The surgery involves microsurgical resection of the malformation.
Many AVMs have associated aneurysms, increasing the danger of hemorrhage.
High-resolution MRI confirms the existence of an AVM, but selective cerebral angiography is usually necessary to identity details of the lesion.
Arteriovenous malformations (AVMs)
Tumors are diagnosed with CT and high-resolution MRI.
Cerebral angiography is used to show the ______ of tumors and aids in determining the type of tumor. It is also used for detection of AVMs.
Vascularity
_______ are weak spots in the walls of arteries that over time will balloon out from the arterial wall, causing
them to thin sufficiently.
They can rupture, causing severe bleeding in and around the brain.
Aneurysms
______________ is a premature closure of the cranial sutures of an infant.
These sutures should remain open up to the age of 2 to allow for brain expansion. If the sutures fuse too early, the brain may be damaged because of insufficient space for growth.
Craniosynostosis
Craniosynostosis repair:
The ______ suture is the most commonly affected suture, creating a long
and narrow skull.
Sagittal suture
Craniosynostosis Repair:
________ _______ suture craniosynostosis creates a short, high head.
Bilateral coronal
Craniosynostosis repair:
_______ _______ suture involvement flattens the frontal bone and orbit.
Unilateral coronal
Within the brain are a series of interconnected canals and cavities called _______.
Ventricles
Name the correct “order” of the ventricles in the brain.
• First and second large lateral ventricles
• Third ventricles
• Fourth ventricles
• Foramen of Monroe
• Aqueduct of Sylvius
• Central canal of the spinal cord
First and second ventricles connect to the third ventricles through the foramen of Monroe
The third ventricle connects to the smaller fourth ventricles located in the Brain stem by the aqueduct of Sylvius
The fourth is continuous with the central canal of the spinal cord
A clear, colorless fluid containing small amounts of protein, glucose, lactic acid, urea, and potassium, as well as a relatively large amount of sodium chloride.
Cerebral Spinal Fluid (CSF)
This fluid helps to support and cushion the brain and spinal cord and stabilizes the ionic concentration of the central nervous system.
It also acts to filter the waste products of metabolism and other substances that diffuse into the brain from blood.
Cerebral Spinal Fluid (CSF)