Procedure Training Flashcards
Where is the IPG implanted?
beneath the clavicle, no labeling for abdomen
What is the first part of the DBS surgery called?
Planning Stage, involves preparing and planning for lead placement
What is included in the planning stage of surgery?
pre-operative review
stereotactic frame
imaging
planning
In what phase is a preoperative MRI used?
in the planning stage, pre-operative review
What are the 4 different types of stereotactic frames?
Leksell (electa) CRW (integra) these 2 are arc frames and are most common Nexframe (MDT) Starfix (FHC)
What is localizer box?
placed over the base of the stereotactic frame to provide additional reference points taht can be seen on the MRI/CT image
What is difference between T1 and T2 scans?
T1: water (CSF) appears dark, lipids (brain matter) appear light
T2: water (CSF) appears light, lipids (brain matter) appear dark
Is T1 or T2 better for the planning stages of DBS and why?
T2 weighted scans provide better visualization of the STN
What is benefit of CT?
shows good contrast btwn bone and brain, can be done preop on the day of surgery with stereotactic frame on, done post operatively also to see the lead
T/F MRI provides better visualization of soft tissue/anatomy
True
What is indirect planning?
doc uses AC/PC reference points and calculates the relative location of the target from the reference points using software and brain atlases, typically from before robust software was established
What is direct planning?
doc directly visualizes the target, typically with a T2 weighted MRI scan, to locate the target
What is trajectory planning?
doc determines the best entry point and pathway to avoid vasculature and ventricles
At what point is the patient woken up during surgery?
all sedation is discontinued after the hole is drilled, prior to electrode insertion and testing
In what circumstances would a DBS case be done with the patient fully asleep?
- if the patient is fully dependant on parksinons meds and has too much difficulty functioning without them
- if the patient is uncomfortable with open brain surgery (ex. very young dystonia patients)
What is a burr hole and how deep is it?
a burr hole is a hole, usually 14mm, that is surgically drilled in the skull to provide an access point for the lead into the brain
What is the burr hole cover?
a lead fixation device that is mounted around the burr hole
What are the steps of the lead placement stage? (there are 8)
- OR setup
- anesthesia
- burr hole
- microdrive
- MER
- test stimulation
- lead fixation
- closure
What is a microdrive?
a device used to accurately insert and position any electrode in the brain. It is usually placed on the arc portion of the stereotactic frame to utilize the frame’s coordinate system. Once the burr hole is drilled, the microdrive and the full stereotactic frame are fixed to the coordinates determined from the planning stage
What is the first step of MER?
to guide a fine microelectrode wire along the planned trajectory to the target using the microdrive
Why is MER important?
The unique firing patterns both indicate the location of the target structures and also identify the boundaries of the structure (like if the electrode has gone too far)
What comes after the lead placement stage?
IPG implant and Post-Op Care
How deep can the Vercise Gevia IPG be implanted?
2cm (because of charging unit) subclavicuclarly
What does neurodegenerative mean?
worsen over time
T/F: Patient may be asked to stop taking meds 12 hours before the programming session to increase the effectiveness of the programing in reducing the usual symptoms
T
What are the steps of IPG Implant and Post-Op Care? There are 4
Extension
IPG Implant
Programming
Post-operative Care
Relative to the STN, what side effects are caused if the lead is too ventral? and what is the unintended target?
SUBSTANTIA NIGRA, acute depression, personality changes, impulsive behavior mood changes
Relative to the STN, what side effects are caused if the lead is too anterior? and what is the unintended target?
INTERNAL CAPSULE: muscle contractions, face pulling, dysarthria
Relative to the STN, what side effects are caused if the lead is too medial? and what is the unintended target?
RED NUCLEUS: paresthesia, nausea, sweating, “on a boat”
Relative to the STN, what side effects are caused if the lead is too lateral? and what is the unintended target?
INTERNAL CAPSULE: muscle contractions, face pulling, dysarthria
What is the name of the MDT software?
Stealth station
Brain Lab elements is Brain Lab
In what MRI would the ventricles be dark and why?
T1, liquids are dark, brain matter is light
is this better or worse for DBS planning? Worse, we want lipids and brain matter to be dark (liquids are light)
