DBS Final Exam Questions Flashcards
What are common Parkinson’s Symptoms
T - Tremor
R - Rigidity
A - Akinesia
P - Postural Instability
DBS can treat what symptoms?
B -Bradykinesia
A - Akinesia
R - Rigidity
T - Tremor
What PD symptoms does DBS NOT treat
Postural Instability
Speech
What are the indications for DBS therapy with Parkinson’s Disease?
Bilateral Stimulation of the internal globes pallidus (GPi) or the subthalamic nucleus (STN) using DBS for Parkinson’s control is indicated for adjunctive therapy in reducing some of the symptoms of advanced, levodopa-responsive PD not adequately controlled with meds.
Differences between ET and PD
ET - Postural (hands outstretched), Kinetic (action tremor present during movement).
Postural tremor immediately observable - resting tremor less common
Bilateral tremor
Frequency 4-10Hz
50% family history
Positive response to alcohol, primidone, and propranolol.
Tremor effects hands, head, voice but rarely legs
No BD,rigidity, postural instability
PD - Resting and postural tremor (re-emergent). Postural tremor observable after mean latency of 5 secs, rarely kinetic tremor. Age of onset - 55-65 Unilateral/bilateral tremor 4-6Hz resting 4-10Hz postural Med response to anticholinergics, Ldopa Worsen tremor with stress Hands, legs. Rarely head or voice Brady, rigidity, post instability
What are ET DBS indications
Unilateral VIM DBS stimulation
Suppression of tremor in upper extremity
Symptoms not adequately controlled by meds
Tremor constitutes significant functional disability.
Dystonia DBS indications
HDE - Humanitarian indication
Unilateral or Bilateral stimulation in GPi or STN
Chronic, intractable (drug refractory) primary dystonia including
generalized(multifocal) whole body
segmental(focal) limited to one area
hemidystonia (one side of face/jaw) and cervical (torticollis)
Must be 7 years or older.
OCD DBS indications
HDE
Bilateral stimulation or anterior limb of internal capsule(AIC)
Adjunct to meds
Alternative to anterior capsulotomy
Chronic, severe, treatment-resistant (OCD)
Adults (18+)
Failed 3 SSRI’s
What structures make up the Basal Ganglia?
Striatum- Putamen, Caudate - cortical input
Globus Palidus - Gpe, Gpi - output to thalamus
Subthalamic Nucleus (STN)
Substantia Nigra - Midbrain structure that makes dopamine
DBS product indications for various disease states (INS, Leads, Targets, Uni/Bilateral)
Kinetra- not approved for ET or Dystonia
Activa RV - not approved for OCD or Dystonia
Soletra/PC/SC - all disease states
3387/3389 - ET/PD/DYST
3391 - OCD
Vim - ET
STN/GPi - PD / DYST
AIC- OCD
Bilateral - PD/OCD
Uni only - ET
Uni or Bilateral- DYST
What are the lead spacing differences?
3391 - large - 3mm x 4mm x 3mm spacing
3387 - 1.5mm x 1.5mm spacing
3389 - 1.5mm x 0.5mm spacing
INS header block lead configuration
0-7 - Top = Front = Left Hemisphere
Soletra/Kinetra/SC/PC/RC
8-15 - Botton = Back = Right Hemisphere
(Kinetra/PC/RC)
How to make an appropriate size pocket
1 finger width below clavicle
3 finger widths from sternum (bilateral INS need to be 8in or 20.3cm apart)
Horizontal incision or alternative depending on patient preference (2in incision)(we can also place abdominally if hunter)
Depths 1cm-RC. 4cm PC/SC
2 finger width deep
How to tunnel
1 prepare pocket and expose lead
Select tip on tunneler 1 lead any tip; 2lead only larger bullet or wedge will work
Bend tunneler, attach tip
Superior to inferior- avoid major structures and over clavicle
Raise table to hip level before tunneling
Straight non-weaving motion
When at pocket remove tip and add appropriate size carrier
Put lead in, screws down (use finger to separate if bilateral config)
Pull extension back/forth to ensure no snag is present.
Normal range impedance values defined in software.
Unipolar 250-2000
Bipolar 250-4000
What impedance values indicate a possible OPEN connection? What are potential causes?
Soletra - over 2000
Kinetra - over 4000
PC/SC/RC - over 40000
Connection issue
Wire fracture
Incorrect lead configuration (using pocket adapter)
What impedance levels indicate possible short circuit? Potential causes?
Below 250
Insulation breaks between electrodes
Kink wires
Damaged components
What does Lead connection check LCC test? How to access feature and why use it?
Counts the number of OK electrodes using patient programmer.
8 electrodes PC/RC
4 SC
Ok=not open circuit but doesn’t check for short or other problem.
Make sure you know how many electrodes patient has when using this test.
Press both black buttons on programmer when initially powering on programmer.
Used when 8840 programmer is unavailable and need to test lead/extension connections.
Where is stimulation strongest?
Cathode (-) 4 x stronger
Ohm’s law
V= I x R
What are qualities of an OPEN circuit?
Impedance high
Current low
Soletra - over 2000
Kinetra - over 4000
PC/SC/RC - over 40000
What are qualities of a short circuit?
Impedance low
Current high
Less than 250
What actions are necessary to perform on INS devices before going to MRI?
All Activa - turn system off (no other actions necessary)
Kinetra - Disable Reed Switch, Disable Day Cycling, Turn Off
Soletra- Run impedance check(tests for open/shorts and verifies parameters), set amp to 0, set to bipolar configuration away from standard therapy, turn off
Activa MRI guidelines
MRI done only if necessary
Transmit/receive head coil only
1.5 T closed horizontal bore
Verify system integrity (impedance check for open/short)
Specific absorption rate SAR set to 1/10 (0.1) W/kg
20 T/s or less gradient field
