Neurosurgery overview 2 Flashcards
Head injuries can include
deceleration injuries: coup & contrecoup lesions
skull fracture
-linear: subdural or epidural hematomas
-basilar: CSF rhinorrhea, pneumocephalus, and cranial nerve palsies- Battle’s sign, Racoon/Panda eyes
depression: brain contusion
Primary brain injuries include
biomechanical effect of forces on the brain at time of insult- no treatment, continues to evolve contusion concussion laceration hematoma
Secondary brain injuries include
represents complicating processes related to primary injury- minutes, hours, days after primary injury
intracranial: hematoma, increased ICP, seizures, edema, vasospasm
Prehospital management for head injury includes
starts at the accident site
CAB
stabilize prior to transport
GCS <9: level 1 trauma center
Airway considerations for a head injury include
assume C-spine injury until otherwise proven radiographically
in-line stabilization
intubate early
full stomach precautions
awake FOI if difficult airway is anticipated
blind nasal intubation is CONTRAINDICATED in presence of basilar skull fracture
Anesthetic considerations for head injury include
hypotension bradycardia maintain HCT >30% seizure prophylaxis DIC may be seen with severe head injuries; treat with platelets, FFP, cryoprecipitate as necessary pituitary dysfunction: diabetes insipidus, SIADH patient remains intubated fluid management?
Nonfunctioning pituitary tumors are
non-secretory
- arise from growth of transformed cells of anterior pituitary
- generally well tolerated until 90% of gland is non functional
Functioning pituitary tumors are
secretory -Cushing's disease (ACTH) - acromegaly (GH) prolactinomas (prolactin) TSH adenomas (TSH)
Intraoperative considerations for pituitary tumors include
transsphenoidal approach necessitates HOB elevated 10-20 degrees
oral RAE or reinforced ETT
avoid hyperventilation: reductions in ICP result in retraction of pituitary into the sella tursica, making surgical access difficult
potential for mass hemorrhage as the carotid arteries lie adjacent to the suprasellar area
mouth and throat pack: placed to absorb glottic blood and minimize postoperative vomiting of blood
avoid positive airway pressure upon extubation
Preoperative evaluation for the patient with a pituitary tumor includes
visual field evaluation s/s increased ICP endocrine labs electrolytes steroids?
Postoperative management considerations for the patient with a pituitary tumor include
DI is common and is usually self-limiting (resolves within 7-10 days)- treat with vasopressin or DDAVP
SIADH
______ is the leading cause of intracranial hemorrhage
cerebral aneurysm
Cerebral aneurysm is commonly located in
the anterior Circle of Willis
With a cerebral aneurysm, the aneurysm fills with
blood and can rupture, spilling blood into the subarachnoid space, creating a SAH
Cerebral aneurysms can lead to
permanent brain damage, disability, or death
Unruptured cerebral aneurysm symptoms include
headache unsteady gait visual disturbances (loss, diplopia, photophobia) facial numbness pupil dilation drooping eyelid pain above or behind eye
Ruptured cerebral aneurysm symptoms include
sudden, extremely severe HA N/V LOC, prolonged coma focal neuro deficits hydrocephalus seizure s/s of increased ICP
Describe considerations with vasospasm as it relates to ruptured cerebral aneurysm
causes ischemia or infarction exact mechanism not known accounts for 14% of M/M digital subtraction angiography is the gold standard for diagnosis use calcium channel blockers
With rebleeding with a rupture cerebral aneurysm
rebleeding follows initial SAH peaks seven days post incident
major threat during delayed surgery
accounts for 8% of M/M
antifibrinolytic therapy
Treatment for vasospasm includes
triple H therapy (goal is to treat ischemia with an increased CPP)
hypertension- SBP 160-200 mmHg
hemodilution- Hct 33% provides balance between O2 carrying capacity and viscosity
hypervolemia- aggressive IV infusion of colloids & crystalloids for CVP >10 mmHg or PCWP 12-20 mmHg
The rationale for vasospasm treatment includes
intended to increase CBF in brain areas that become ischemic due to intense vascular narrowing
normally, increased CBF would not result from increased BP, however with vasospasm the vascular bed becomes passive
therefore increasing CPP by increased volume or by systemic administration of vasoactive drugs may reverse symptoms of cerebral ischemia
Endovascular coiling considerations include
GETA with complete muscle paralysis control CPP minimal narcotic needs since minimally invasive a-line preferred minimal to no blood loss heparin may be used for ACT 200-250 same postop concerns and with clipping
Endovascular aneurysm coiling involves
detachable coil inserted into aneurysm
standard arteriogram is performed to locate aneurysm
catheter is passed, often through femoral vessels, and coil is advanced
Advantages to endovascular aneurysm coiling includes
shorter stay, less anesthetic requirements, uncomplicated positioning, minimally invasive
Complications of endovascular aneurysm coiling include
aneurysm rupture/subarachnoid hemorrhage- rapid transport to OR for clipping is necessary
vasospasm
CVA
incomplete coiling
A cerebral aneurysm presenting to the operating room is most commonly treated by
microsurgical clip ligation
craniotomy approach; parent vessel giving rise to aneurysm is identified
aneurysm neck is isolated, and a clip is placed across the neck, excluding it from circulation
deep circulatory arrest may be necessary with giant aneurysms
Goals of anesthesia for cerebral aneurysm intraoperative management include
maintain optimum CPP
decrease CPP rapidly if rupture occurs during surgical clipping
maintain transmural pressure (MAP-ICP)
decrease intracranial volume (blood and tissue); provide “slack” brain
minimize CMRO2
Preinduction for the patient with cerebral aneurysm includes
limit sedation (hypercapnia) a-line 2 large bore PIVs T&C 2-4 units PRBCs remember HOB will be turned 90-180 degrees
Induction for the patient with cerebral aneurysm includes
smooth induction- difficult airway, full stomach
aggressive BP & HR control- narcotics, BB, deepen anesthesia
Describe maintenance for the patient with cerebral aneurysm
may use TIVA or anesthetic gases
temporary occlusion of a cerebral artery
maintain BP 15-20% below baseline to prevent vasospasm, decrease EBL and allow for better exposure & visualization
employ methods for cerebral protection and to reduce ICP if necessary
Fluid management for the patient with cerebral aneurysm includes
run pt dry <10 mL/kg + UOP
expand blood volume with colloids
have PRBCs available
no GLUCOSE CONTAINING SOLUTIONS
Describe control of BP for the patient with cerebral aneurysm
control of BP is critical to successful outcome of case
surgeon may ask for temporary increase in MAP to 80-100 mmHg to provide for collateral flow if a feeder vessel is clamped for a short period to allow for clipping of aneurysm
post clipping, MAP is usually kept at 80-100 mmHg
Likely times of aneurysm rupture include
dural incision
excessive brain retraction
aneurysm dissection
during clipping or releasing of clip
Treatment of intraoperative aneurysm rupture includes
immediate, aggressive fluid resuscitation and replacement of blood loss
propofol bolus for brain production, to decrease MAP, and decrease blood loss
decrease MAP to 40-50 mmHg (clevidipine, labetalol, esmolol)
surgeon may apply temporary clip on parent vessel to control bleeding, restore BP after clipping to improve collateral flow
Arteriovenous malformation considerations include
AVM is congenital abnormality that involves a direct connection from an artery to a vein “nidus” without a pressure modulating capillary bed
-most common presentation intracranial hemorrhage*****
Treatment for AVM includes
intravascular embolization, surgical excision or radiation
Preoperative considerations for AVM include
same as with aneurysm
potential for significant blood loss is much higher (upwards of 3L)
Cranial nerve decompression treats
disorders of cranial nerves such as trigeminal neuralgia, hemifacial spasm, & glossopharyngeal neuralgia
unilateral
usually caused by compression of a vascular structure
Describe positioning for cranial nerve decompression
lateral, prone or supine
Describe monitoring for cranial nerve decompression
facial nerve, brainstem auditory evoked response, EMG
Describe anesthesia for cranial nerve decompression
TIVA
brain relaxation
PONV- multimodal
Spinal cord surgeries include
spinal cord stimulators- MAC intrathecal pumps- asleep in lateral scoliosis ALIF/TLIF ACDF
