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Neuromodulation for chronic intractableprimary headache
Laurence WatkinsVictor Horsley Department of NeurosurgeryNational Hospital for Neurology & Neurosurgery
BASH Hull January 2011
Neuromodulation in primaryheadache disorders
Peripheral neuromodulation Occipital nerve stimulation
Central neuromodulation Deep Brain Stimulation
Why? Results Procedure Future
Occipital headaches
Weiner 1995: ONS in patients who had responded to repeated GON injection
Copyright restrictions may apply.
Matharu, M. S. et al. Brain 2004 127:220-230; doi:10.1093/brain/awh022
Statistical parametric map (SPM{F}) showing brain regions in which rCBF correlates (positively or negatively) with pain scores, in particular the dorsal rostral pons, ACC and cuneus (voxels
significant at P
Copyright restrictions may apply.
Matharu, M. S. et al. Brain 2004 127:220-230; doi:10.1093/brain/awh022
Graphs showing (A) mean pain scores and (B) mean scores of stimulator-induced paraesthesia by scanning states
Cervico-trigeminal-hypothalamic system
Results of ONS in cluster headache Burns B; Watkins L; Goadsby P.
Lancet 2007 369:1099-1106 Treatment of medically intractable cluster headache by occipital nerve stimulation: long term follow up of eight patients
8 patients with chronic cluster headache Median 12 years since onset Median 6 years since became
chronic Median age 46 years (32-58)
Median follow up 20 months n=8
2 patients substantial improvement 90-95% reduction
3 patients moderate improvement 40-80% reduction
1 patient mild improvement 25% reduction
6 said they would “recommend it to other CCH patients”
1 stopped triptan use and 2 reduced 2 patients no improvement
First Meeting
Check have been fully assessed in Headache Neurology Clinic (chronic, disabling, intractable)
General fitness & airway satisfactory; reflux?
MRI ? (because can’t have MRI once ONS is implanted)
Any major surgery planned ? (because restriction of monopolar diathermy once ONS implanted)
Explaining procedure
Discussion with patient
Describing the procedure Relatively novel operation – NICE
assessment “in progress” 200+ patients so far in our unit since
2002. Now about 1 per week. Known risks: next slide Clearance from PCT
Discussion with patient
Known risks: may not help infection requiring removal of implant electrode migration neck stiffness breakage or failure of components tethering to skin or muscle skin erosion early depletion of battery
Clearance from PCT
Follow up clinics
Typically 4 in first year Joint assessment with Headache
Neurologist and Specialist Nurse (usually on day care unit)
Gradually refine the settings to get best response (headache diary), without patient discomfort
Checking for any problems
Stages of the operation
Insertion of electrodes LA + Sedation
Test stimulation of electrodes Awake
Insertion of battery and tunnelling of leads
Asleep (GA with LMA) Alternatively GA throughout if difficult
airway or reflux USA: 2 stage procedure
Skin marking
Awake, sitting upright on stool Midline Intermastoid line Spinous process of C1 3cm from midline Chosen position of battery
Positioning
Lateral position Access to all operative areas Strict aseptic technique to
establish field Anaesthetist access to patient for
communication and airway
Test stimulation
Radiating occipital paraesthesiae bilaterally
300 microseconds pulse width 60-80 Hz At low amplitude – typically 1-2V If no paraesthesiae or if amplitude
>4V then reposition electrode
2-3 days later Activate implant Set initial parameters Pleasant radiating occipital paraesthesiae
bilaterally Patient education to use handset for continuous
comfortable stimulation Patient given implant ID card Advised to restrict strenuous activity in first 8
weeks Drive when comfortable, but switch implant off
while driving Restrictions after 2 months: no MRI, scuba
diving below 10m
Real Life
Some dramatic results but have to give realistic expectation to patients. Approximately 70% will be pleased with result and 30% disappointed.
Relatively low risk; so may be justifiable in cases where chronic headache is disrupting quality of life and intractable to medical treatment
Main technical challenges
Placing electrodes to get paraesthesiae Anchoring/looping the electrodes Minimising infection risk Not “instant” result so can’t really do “trial
electrodes”
Experience with bion
Single electrode on 3cm rechargeable “capsule”
Unilateral Need to map position of nerve with
subcutaneous needle electrode Then place bion at optimal point
Experience with bion
Implanted 10 All unilateral syndromes 6 hemicrania continua 5/6 benefit Faster onset of benefit (approx 2
weeks) cf cluster (months)
Limitations of bion
Unilateral Thus not ideal for chronic migraine
and cluster Single electrode Thus need nerve mapping and
precise placement Frequent recharging (daily or in
some patients several times per day)
Advantages of bion
No wires to tunnel Thus can be done with local
anaesthetic only Shorter operation No migration because no wires
causing tension
Next Steps RESPONSE trial of ONS in chronic
migraine (large, multicentre, randomised controlled trial)
CE marking & NICE assessment Rechargeable stimulators Smaller stimulators More experience Interplay between medication and
neuromodulation Other inputs into CTH system
Cervico-trigeminal-hypothalamic system
Neuromodulation in primaryheadache disorders
Peripheral neuromodulation Occipital nerve stimulation
Central neuromodulation Deep Brain Stimulation
Conclusions
Consider in patients with chronic, disabling, intractable primary headache
ONS and DBS are both “low risk” when practiced in a multidisciplinary team and in experienced hands (but the rare complications in DBS can be severe)
Conclusions
May be logical to see ONS as primary surgery and reserve DBS for those who don’t respond or can’t have ONS
Thank [email protected]