Thalamic pain and electrical stimulation of the motor cortex

Thalamic pain (thalamic pain)
Definition
   Thalamic pain, also known as Déjerine-Roussy thalamic pain syndrome, is usually secondary to hemorrhage or infarction of the thalamic striatal artery or the thalamic geniculate artery. It is a common sequel to thalamic stroke and is a typical central post-stroke pain (CPSP), incidence: 8%-17%. 
Ni Bing, Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University
Etiology
     Thalamic hemorrhage, thalamic infarction, thalamic regional surgery, vasculitis?
Clinical manifestations
       contralateral spontaneous pain, contralateral mild hemiparesis, contralateral superficial sensory loss or abnormality (temperature sensation), less deep sensory loss, contralateral involuntary movements, ataxia, tardive dyskinesia, depression, anxiety, sleep disturbance, language and cognitive impairment due to primary disease, cranial nerve injury, etc.
Pain characteristics
       Time of onset: immediately after stroke, or within months to six months, a few more than 1 year; location: vague, diffuse, more on the contralateral limb than on the head and face, with large individual differences; duration: mostly persistent pain; characteristics: burning, pinprick, crushing, cutting, cold, etc.; aggravating factors: sound, light, wind, touch, emotion; severity: severe, unbearable, not proportional to the size of the lesion
Auxiliary examinations
     Electromyography, MRI
Treatment-medication
       Antidepressants: amitriptyline, fluvoxamine, fluoxetine; anticonvulsants: lamotrigine, carbamazepine, gabapentin, pregabalin; cell membrane stabilizers: mexiletine (p.o.), lidocaine (IV) (short term); NMDA antagonists: ketamine; neurotrophic drugs; opioids; NSAIDs & COX-2 inhibitor
Treatment
Treatment – deep brain nucleus destruction surgery
     Nuclei: VPL, VPM, centromedian nucleus (CM), parafascicular nucleus (PF), etc.
     Conduction tracts: middle pontine tract, trigeminal tract
     cingulate gyrus
Treatment – electrical stimulation
     Motor cortex stimulation (MCS)
Treatment
¡ Transcranial magnetic stimulation (rTMS)
 
¡ Targeted area: the corresponding area of the contralateral precentral gyrus
 
¡ Can be used as a test treatment for MCS