Neurosurgery Flashcards
What is Functional Neurosurgery?
-Surgical management of disorders with no gross anatomical target
-Treatment of movement disorders: Parkinson’s, dystonia, essential tremor, epilepsy, OCD
-Ongoing research and treatment of pain, depression, Tourette, headaches, chronic pain, MS
-Goal: provide symptomatic relief, improve quality of life
What is Deep Brain Stimulator Therapy?
-One of the most common Functional Neurosurgeries.
-Placement of electrodes into deep brain structures, connected to pulse generator
-Exact mechanism of action is not fully understood
-Advantages over surgical ablation: nondestructive, reversible, and adjustable.
-Well documented safety and long term benefits.
-Inhibition and/or activation of GABAnergic cells and decrease in production of glutamate
-Parkinsons (need dose of Levodopa on DOS), essential tremor, seizures, dystonias
Describe the Anesthetic Management of Deep Brain Stimulator therapy?
DBS insertion often a 2-part procedure:
1st – awake craniotomy for lead placement
2nd – GETA for electrode and generator placement
Anesthetic goals: suitable surgical conditions, patient safety and comfort
What are Contraindications/Cautions for DBS therapy?
Contraindications: coagulopathy, recent use of antiplatelets, and uncontrolled HTN
Caution with: confusion, extreme anxiety, communication difficulties
Describe the Initial Insertion of a Vagal Nerve Stimulator.
-Indicated for seizures unresponsive to meds
-Electrical stimulation to vagus nerve in neck, electrode tunneled to chest wall generator
-GETA
-Can cause bradycardia when testing device
Describe a Generator Change of a Vagal Nerve Stimulator?
-Can be done under local/sedation
-Similar to pacemaker battery
-Chest wall pocket
Describe anesthetic management of a Spinal Cord Stimulator
Anesthetic technique is surgeon and pt dependent:
-Sedation (heavy MAC)
-GETA
-+/- IONM
-Prone positioning
-May require “wake-up” test to determine proper lead placement
-Often a very challenging anesthetic due to chronic pain and opioid use
-Can be very painful procedure if laminectomy and during tunneling
What is Spinal Cord Stimulation used for?
-Spinal cord stimulation is a pain-relief technique that delivers a low-voltage electrical current to the spinal cord to block the sensation of pain.
-It is widely used and efficient alternative for the management of refractory chronic pain that is unresponsive to conservative therapies
-Mechanism of action originally based on Gate-Control Theory, but as more research is done, it also seems to activate GABA and adenosine receptors
What is a Baclofen Pump used for?
-Baclofen indicated for relief of spasticity r/t to paralysis, CP)
-Lateral position, exposed abdomen and spine
-Allows for access to abdomen and laminectomy site
-Abdominal wall pocket with pump, contains baclofen, tunneled tubing to spine, insertion site in spine at above level of spasticity
-GETA
-Positioning challenge r/t contractures
What are indications for Craniotomy?
-Gliomas - most common, large areas of edema, respond to corticosteroids
-Meningioma – slow glowing, very vascular
-Pituitary adenoma – arise from sella turcica, associated endocrine dysfunction
-35% are secondary neoplasms (breast, lung)
-Slow growing, can be very large before symptoms appear
Describe setup and maintenance of Craniotomy
-Euvolemic, arterial line, 2 large bore IV’s, monitor fluids, ICP if available, avoid fluids with dextrose, Lactated Ringers, T&C,
-Blood sugar monitoring, ABG’s
-2 large bore IV’s with extensions if arms tucked (careful of kinking) one IV with blood tubing
-Adequate relaxation and anesthesia
-Intra operative neuro monitoring?
-Arterial line
-Decadron (none for TBI)
-Antibiotics
-Anti-convulsant, mannitol available
-Extension for circuit, IV’s, BIS monitor, Precordial stethoscope, Esophageal
-Bair hugger, fluid warmer
-Drips available if needed, propofol, neo, +/- esmolol, have lebatolol
-Propofol ready for PINS, or if tunnel procedure, have in line ready to go
-Full Reversal, smooth wake up, prevent bucking (lidocaine)
-Intubated to ICU? Monitors, Report
Describe Management of Pituitary Surgery?
-Evaluate pt for hormone hypersecretion
-Steroids (hydrocortisone) typically given intra-op
-Transphenoidal or endoscopic nasal approach more commonly used than intracranial approach, bed may be 90 degrees or 180
-GETA , sitting or semi-fowlers position (caution with VAE)
-Tumor may grow around optic nerve, internal carotid artery, or cavernous sinus – be prepared for blood loss
-Monitor for post-op DI, SIADH
-Tx for DI – DDAVP, vasopressin gtt, fluid restriction
-Pt may suffer from acromegaly or cushing’s syndrome. Airway, cardiac concerns
-Visual Disturbances
Describe Transsphenoidal Tumor Resection.
-Endoscopic approach decreases trauma, minimizes blood loss, allows for direct assessment to pituitary, decreased incidence of DI and hypopituitarism.
-Less invasive and pt often go home POD 3
Anesthetic goals: optimize cerebral oxygenation, maintain hemodynamic stability, provide ideal surgical field (minimal EBL), and smooth emergence
Describe Posterior Fossa Surgery
Posterior Fossa holds vital structures.
-Cerebellum, mid pons, medulla
-GETA
-TIVA v ½ MAC, PIV x 2 or central line, Aline, IONM
-Positioning challenges – prone, lateral, sitting
What are risks associated with the Sitting Position?
VAE, pneumocephalus, quadriplegia from severe neck flexion, spinal cord compression, increase cerebral venous congestion
