neuro anatomy/basics pt 2

cervical plexus of spinal cord

nerve plexus of C1-C4, provides motor innervation to some muscles of the neck, and diaphragm, and sensory innervation parts of the head, neck, and chest

phrenic nerve of spinal cord

mixed nerve arising from the anterior C3-C5 spinal nerves, which are components of the cervical plexus, arises int he neck through the thorax and end on diaphragm, main function is to provide the entire motor innervation to the diaphragm, which makes it vital for breathing

brachial plexus of spinal cord

group of nerves that connect the spinal cord to the shoulder, arm, and hand (axillary, radial, ulnar, and median nerve)

lumbosacral plexus of spinal cord

a complex network of nerves that arises from the lumbar and sacral spinal nerves (L1 to S4) and supplies the lower extremities, pelvis, and some part of the abdominal wall (sciatic nerve)

synapse- neurotransmitters

carry chemical signals “messages” from one neuron (nerve cell) to the next target cell (nerve cell, muscle cell, or gland)

synapse/ neurotransmitters help control what body functions?

heart beat, blood pressure, breathing, muscle movements, thoughts, memory, learning, feelings, sleep, healing and aging, stress response, hormone regulation, digestion, sense of hunger and thirst, and senses

synapse/neurotransmitter are made up of what 3 parts?

cell body, axon, and axon terminal

cell body of synapse

vital to producing neurotransmitters and maintains he function of the nerve cell

axon of synapse

carries the electrical signals along the nerve cell to the axon terminal

axon terminal of synapse

where the electrical message is changed to a chemical singular using neurotransmitters to communicate wit the next group of nerve cells, muscle cells, or organs

what are the 3 possible actions neurotransmitters transmit?

excitatory, inhibitory, and modulatory

excitatory action

“excite” the neuron and cause it to “fire off the message”, meaning the message continues to be passed along to the next cell (example include epinephrine and norepinephrine)

inhibitory action

block or prevent the chemical message from being passed along

modulatory action

influence the effects of other chemical messengers, they adjust how cells communicate at the synapse

how do neurotransmitter clear the synaptic cleft after they deliver there message?

fade away, reabsorb and reused by the cell that released it, broken down by enzymes within the synapse so it can’t be recognized or bind to the receptor cell

scientists know of how many neurotransmitters?

at least 100

vertebral body is where?

anterior

neural arch

being the pedicles/lamina posteriorly encircles the opening for the spinal cord along with vertebral body

vertebral foramen

is body, pedicles, and lamina- spinal cord surrounded by vertebral foramen and passes through it

vertebral pedicles

extend posteriorly from back of each vertebral body

transverse process

projects laterally and at junction pedicles and lamina, point of attachment muscles/ligaments for movement and stability

vertebral lamina

are the plates of bone that form posterior walls each vertebrae

spinous process

projects posteriorly and perpendicular to the midline of the lamina, point of attachment for muscles/ligaments for movement and stability

vertebral facets

are located between the vertebra and form the articulating surface, connections between the bones of the vertebra, 4 per each vertebra (superior and inferior), allow the spine to bend and twist

neural foramen

openings in spine that allow nerve roots to exit and branch out of other part of body

what are the 3 important ligaments in the spine

ligamentum flavum, anterior longitudinal ligament, and posterior longitudinal ligament

ligamentum flavum

forms a cover over the dura mater, a layer of tissue that protects the spinal cord, this ligament connects under the facet joints to create a small curtain over the posterior openings between the vertebrae

anterior longitudinal ligament

attaches to the front (anterior) of each vertebra, this ligament runs up and down the spine (vertical and longitudinal)

posterior longitudinal ligament

runs up and down behind (posterior) the spine and insides he spinal canal

what are preoperative tests that may be run

CT, doppler, brain scan, MRI, X-ray with out without dye (myelogram), angiography, ultrasound, EEG, and lumbar puncture

what is a myelogram often used to diagnose

brain tumor, bone spurs, herniated disc, spinal stenosis, spondylitis

what positions are used for cranial procedures?

sitting or supine

what are various head holders and skull fixation devices available for cranial procedures?

gardner wells, mayfield, and stereotactic

stereotactic biopsy

a surgical procedure where a thin needle is inserted into the brain to extract a small piece of tissue to examine under a microscope

what position is used for spinal procedures?

supine (anterior approach) and prone or sitting (posterior approach)

what frames and devices are available for prone positioning for spinal procedures?

bardin pads, wilson frame, Andrew frame, chest rolls, and hall frame (lots of padding needed and make sure no tissue is pinched)

what are monitoring devices used during neuro procedures?

foley catheter, invasive monitoring (arterial line, CVP, swan-ganz Cath), SCD’s, nerve or spinal cord monitors, and warming devices

why is methylene blue never used to mark the incision site?

it produces and inflammatory response of the CNS tissue and could be fatal if injected into the subarachnoid space

what is injected into the incision site for neuro procedures?

local anesthetics (xylocaine, lidocaine, sensorcaine) may be combined with epi in increase strength and duration of anesthetic effect and constrict blood vessels to reduce bleeding because the scalp is very vascular

examples of hemostatic agents used in neuro procedures

raney scalp clips, bone wax, ESU, Malis irrigating bipolar, gel foam, surgical, oxycel, or patient’s own fat or muscle

raney scalp clips

applied to the skin edge and galea of the scalp to apply pressure by compression (don’t fully open too soon or they lose their memory)

bone wax

firmly rubbed onto the bleeding surface of bone (skull or vertebra)

ESU

bipolar most often used because the current is isolated and less of it is required, less chance of damage to nerves, vessels, and surrounding tissue

malis irrigating bipolar

irrigation cools and protects tissue (patient safety)

gel foam

compressed sponge, cut into small pieces, can be used wet or dry

surgicel

cellulose gauze

oxycel

cotton and gauze forms

patient’s own fat or muscle for hemostatic agent

it can control bleeding in spots where other forms of hemostasis are not possible

what are two kinds of hemostatic clips available and what are they made of?

Mckenzie and Samuels, made of an alloy so it is compatible with MRI (titanium)

examples of sponges commonly used in neuro procedures

raytec, cottonoid patties, and cottonballs

raytec sponges (gauze)

used before skull or spinal cord are opened (risk of injury if used with fragile brain or spinal cord tissue)

cottonoid patties (compressed rayon cotton)

used on the brain and spinal cord, variety of sizes, have radiolucent markers in them, are used wetted with saline or LR

cotton balls

used for gentle pressure in bleeding tumor beds

what is stereo static equipment often used for?

to precisely localize the biopsy site, this system maps the brain in a 3D coordinate system, allowing the surgeon to select accurate target coordinates for guiding the biopsy needle

stealth system (navigation system)

incorporates each patients MRI or CT scan into the computer to create a 3D model, it uses a navigational system to the guide the surgeon’s movements and instruments during the procedure

what are benefits of the stealth system?

localization accuracy by creation of virtual surgical plain, 3D anatomy, reduced cost, reduced hospital stay, technology can be moved from room to room

O-arm imaging system (navigation system)

provides on-demand imaging, robotic positioning, 2D and 3D imaging, utilized for medical screw insertion, and facilitates a safer dissection with guidance of instrumentation with spine surgery

advantages of microscope

increased magnification and increased light

peripheral nerve stimulator

a non-opioid pain management system for chronic and acute pain, ultrasound is used to place small lead wire and outputs stimulation using a small bluetooth enabled controller

what is a peripheral nerve stimulator used for

post amputation pain, nerve trauma, post-operative joint pain, post-joint replacement pain, lower back pain, inoperable joint pain, complex regional pain syndrome, and various mononeuropathies (damage to a single nerve)

intracranial pressure monitor

measure the pressure inside the skull and is inserted into ventricles

what are causes of increased ICP

brain injury, cranial surgery, brain infection, or other problems leading to swelling of brain

gliadel wafers (chemo wafer)

implanted to treat brain cancers, made of chemotherapy drug that works by sticking to one of the cancer cells DNA strains, which slows or stops cancer cell growth, placed following surgery and slowly dissolves releasing the medicine

how are the number of gliadel wafers placed and what is the max number placed?

number depends on the amount of space available and can place up to 8

what kind of cancer do gliadel wafers treat?

malignant gliomas, including glioblastoma multiform (GBM), anapestic astrocytoma, anapestic oligoastrocytoma and anapestic oligodendroglimoa

what are the most common type of primary brain cancer in adults?

gliomas

what is the current standard of treatment for malignant gliomas?

surgical resection of tumor, radiation therapy, systemic chemotherapy orally or intravenously, treatment is patient specific

what are advantages of chemo wafers?

provide targets therapy resulting in fewer systemic side effects

what are disadvantages of chemo wafers?

have the potential to destroy healthy cells

what are common sutures used for neuro surgery?

nylon silk, prolene, ticron, wire, and vicryl

how many wound classifications are there?

4

class 1 : clean wound classification

incision made under ideal surgical conditions, no break in sterile technique, primary closure, no wound drain, no entry into GI or GU tract (many procedures for neuro are this type)

class 2: clean contaminated would classification

primary closure, wound drained, minor break in sterile technique occurred, controlled entry into GI or GU tract

class 3: contaminated would classification

open traumatic wound (less than 4 hours), major break in sterile technique, acute inflammation present, entry into GI or GU tract with spillage

class 4: dirty/infection would classification

open traumatic wound more than 4 hours, microbial contamination prior to procedure, perforated viscera-abdominal organ such as intestines, stomach, and appendix, old traumatic wound with necrotic tissue, gross infection

what neuro procedures would be classified as dirty/infected?

brain abscesses, infected implant with revisions, traumatic injury with debris in an open wound (antibiotic irrigation probable on these procedures)