Flashcards in Functional Deck (106):
What is the most common type of tremor?
What types of tremor do you know?
What are the features of ET?
Mostly upper limb
Head 30% and voice 5% involvement
Symptomatic tremor in the lower limbs is rare
No tremor at rest / during sleep
What are the medical treatments for ET?
**Tremor is suppressed with alcohol
What are the features of PD?
What medication types are used for PD?
Dopa agonists - ropinirole
Anticholinergics - amantadine / trihexyphenidyl
MAO-B - selegiline
What are the main side-effects of levodopa?
Dyskinesias - usually develop >5 years after starting levodopa
How can dystonias be classified?
What causes hemiballismus?
Destruction of the STN
What are the targets for ET?
What is the target for tourettes?
CM / PF bilaterally
Where should stimulation of the GPi be for PD?
Dorsal and inferior above the optic tract
What is the best target for ET tremor?
What is the best target for dyskinesias / dystonia?
What is the target for PD?
STN or GPi
How do you calculate the laterality of stimulation site?
Width of the third ventricle
Why is DBS better than lesioning (thalamotomy)?
Safety of bilateral interventions as bilateral lesioning results in severe side effects (loss of corticobulbar function 25% with bilateral thalamotomy)
What are the benefits of DBS over lesioning?
What sensory phenomena do you get with VIM stimulation?
Thumb and angle of mouth with high voltage stimulation
What is the outcome of DBS for MS?
Poorer results with demyelinating causes
How long is the onset of effect with SRS for thalamotomy?
Between 6 weeks and 6 months
Which target for PD has more cognitive issues?
STN! So if patient has pre-existing cognitive issues then target GPi
What is the benefit of STN over GPi?
STN DBS has lower medication requirement so have less dyskinesias
When is GPe targeted?
What are the differences between GPi and STN stimulation for PD?
Overall outcomes are the same but off time and on time with dyskinesia is less with STN; GPi is better for those with baseline mild cognitive dysfunction;
Where is the target for cluster headache DBS?
How do you assess severity of Parkinson's disease?
What is the DBS target for epilepsy?
Anteriomedial thalamic nucleus causes 50% reduction in seizure frequency
What are the inputs to the anteromedial thalamic nucleus?
Medial mammillary bodies, reticular nucleus, entorhinal cortex, subiculum and anterior cingulate
What are the outputs of the anteriomedial thalamic nucleus?
To the frontal cortex and hippocampus so stimulation of the anteromedial thalamic nucleus reduces seizures!
What is the target for occipital neuralgia ganglionectomy?
C2 and 3 ganglionectomy;
Unilateral for unilateral pain and bilateral for bilateral pain;
What is the complication of sympathectomy?
What is the main indication for DREZ lesioning?
Root avulsion, (post-herpetic neuralgia and post-amputation pain)
Does DREZ or myelotomy help phantom limb sensation?
No (but may help for pain if this is due to root avulsion)
How is cordotomy usually performed?
Percutaneous under CT guidance; The spinothalamic tract is identified by stimulation;
When is cordotomy performed?
For severe cancer pain;
Pain relief for roughly 6 months;
Algorithm for trigeminal neuralgia
Slavin et al 2007 head and face medicine
What are the neurosurgical options for spasticity
Medical - NMJ blockers / Benzodiazepine / Gaba agonists / Tizanidine
Surgery - Intrathecal baclofen / dorsal rhizotomy etc / Peripheral neurotomy / Tendinotomy / rhizotomy
Sindou 2007 algorithm - look it up!
What is the definition of spasticity?
Movement velocity dependent increase in muscle tone
(unlike with rigidity which is movement velocity independent)
What is the function of baclofen?
Gaba B agonist
What are the methods of performing functional surgery?
Destruction - chemical / thermal / radiation
Modulation - electrical / chemical / genetic
What are the features of Sudek atrophy?
Reflex sympathetic dystrophy:
What are the types of Chronic regional pain syndrome?
Type 1: ...
What is the management chronic regional pain syndrome?
Thermography to make diagnosis
Vascular testing to ensure no ischaemia of the limb
Anticonvulsants / antidepressants
Sympathetic blocks - some do not respond to this
Surgery - Spinal Cord Stimulators
How do you perform spinal cord stimulation?
Percutaneous insertion into the epidural space
Stimulation trial with electrodes tunnelled to a subcutaneous pocket
Permanent implantation if successful or removal if unsuccessful
What do you do if your pocket with the spinal cord stimulator has pus discharge?
Remove the implanted device, washout the pus!!
Send pus for MC&S
New system once everything heals
Why dont you use radiofrequency for 1st branch trigeminal neuralgia?
To prevent corneal keratitis
(so for V1 TN use balloon to get partial numbness until the patient looses sharp and dull discrimination)
Why don't you want complete numbness with percutaneous TN treatment?
So the patient does not get anaesthesia dolorosa
How do you perform TN thermal ablation?
70 deg C for up to 60-90 seconds
Where is the balloon for treatment in Meckel's cave?
The needle is outside foramen ovale and the balloon is inserted into Meckel's cave
What is the difference between typical and atypical neuralgia?
**Typical trigeminal neuralgia does not have sensory loss**
What would you do if the TN is due to a large basilar artery?
Try and place teflon
If not successful then percutaneous treatments or open rhizotomy can be performed
How do you control bleeding from Dandy's vein (petrosal vein) in TN?
Gelfoam and wait
Where is the lesion made with a DREZ?
Layers 1-5 of the dorsal root
Where do you make the incision in a DREZ?
Dorso-lateral sulcus (lateral to the dorsal root entry zone)
What is a cordotomy?
Interruption of the lateral spinothalamic tract
When is a cordotomy performed?
Mainly for cancer pain to a limb
Which areas of the brain are associated with an acute pain stimulus?
Insula and anterior cingulate cortex (likely emotional response to pain)
How many DA neurons are in the substantia nigra?
How many DA neurons do you lose when you develop PD?
What are the features of PD?
Akinesia / Bradykinesia
Postural / gait abnormalities
What are the targets for PD?
STN > GPi > Thalamus > PPN
What is the main target for essential tremor?
What is the main target for dystonia?
What proportion of the population have PD?
3% over the age of 65 y
What proportion of PD patients are good candidates for DBS?
Is ET more common than PD?
ET 10x more common than PD
What is the somatotopy of the Vim?
Head near the 3rd ventricle and feet near the posterior limb of the IC
What is the problem with chronic leva dopa use in PD?
Less effect of drugs
Unpredictable drug response
What are the risk of DBS?
Hardware failure / migrationI
What structure if STN DBS too anterior?
Corticospinal tracts cause Motor signs
What structure if STN DBS too medial?
3rd nerve causing eye deviation
What structure if STN DBS too posterior?
medial lemnisus causing paraesthesia symptoms
What are the main complications with doing STN DBS in patients >70 years?
Dementia / Depression
What other ways are there of making a lesion in the brain?
ExAblate (focused ultrasound)
How does focused ultrasound work?
MR thermography used to measure the temperature during short burst (13 secs) of high frequency USS. Keep making the lesion bigger until the tremor goes.
What is the problem with bilateral thalamotomy?
Speech impairment (so only done unilaterally and put a DBS on the other side)
If a patient has STN DBS and then develops gait problems. What do you do?
Do PPN in addition to the STN
What is deafferentiation patient?
Loss of sensory input resulting in pain
What are ablative pain procedures in the spine?
When are lesions made in the hypothalamus for pain?
Breast cancer pain (look this up)
What are thalamus DBS targets for pain?
Only 20% improvement:
What are the indication for spinal cord stimulation?
Failed back syndrome
Peripheral Vascular Disease
CRPS type 1
What are type 1 and 2 TN?
TN1 = sudden onset brief severe unilateral pain
TN2 = on-going background pain
Treatments for TN?
Drugs - Carbamazepine
Ablation - Injection (glycerol), avulsion, gasserian neurectomy, radiofrequency ablation, SRD
Non-ablative - balloon compression / neurovascular decompression
What medications are given with deafferentation pain?
(do not do ablative procedures!)
What are the treatments for spasticity?
Selective rhizotomy (for spastic paraplegia)
How do you do a selective rhizotomy?
Under EMG you stimulate the rootlets. Those that are most involved with inducing most contraction / spasticity you cut!
How do myelotomies work?
Cutting the midline fibres to prevent the reflex arc
How do you grade spasticity?
Ashworth scale (0-4)
0 = no increase in muscle tone
4 = held rigid in flexion or extension
What type of pain is best for deafferenation pain?
Spinal cord stimulation
What type of pain is best for somatic type / cancer pain?
Ablations e.g. DREZ if one level / cordotomy if multilevel
What is damaged in post-herpatic neuralgia?
Dorsal root ganglion - reorganisation of input to different rexed lamina
What is a dorsal rhizotomy?
Where the nerve is cut between the DREZ and the dorsal root ganglion
What is the best treatment for post herpatic neuralgia?
For allodynia (sharp tactile pain) do dorsal rhizotomy of the affected levels
For burning pain will not help!
When do you do DREZ vs cordotomy?
DREZ for localised levels whilst cordotomy for whole limbs
What medications can be used to reduce leva dopa induced dyskinesias?
Reduce the dose of L-dopa by spreading the dosing, adding in Dopa agonists (ropinirole / pramipexole), COMT inhibitors and amantadine
What are the side effects of DA agonists.
Impulse control dysfunction
What is the trigeminal depressor response?
Bradykinesia on entering the needle into the ganglion
How do you know when the needle enters the foramen ovale?
Induce contraction of masseter
Which trigeminal neuralgia procedure can be done under LA?
Thermocoagulation (glycerol and balloon compression is under GA)
What are the outcomes of thermocoagulation?
90% instant improvement but pain recurs after 18 months (but anaesthesia dolorosa is more common!)
What are the complications associated with percutaneous treatments of TN?
Wrong division e.g. V1 damage - corneal numbness
Carotid artery injury
Temporal lobe injury
Which percutaneous procedure for TN has the highest pain recurrence?
How many Gy is given to the CN5 for TN?