Thalamic sensory strokes with and without pain: differences in lesion patterns in the ventral posterior thalamus.
OBJECTIVE
Vascular lesions of the posterolateral thalamus typically result in a somatosensory syndrome in which some patients develop central neuropathic post-stroke pain (CPSP). Damage to the spinothalamic tract terminus is assumed to be a prerequisite for thalamic CPSP. At the nuclear level, it remains a matter of debate whether the ventral posterolateral nucleus (VPL) or the posterior portion of the ventral medial nucleus (VMpo) constitutes the decisive lesion site. The hypothesis of the study was that lesion location in thalamic CPSP patients differs from that in thalamic stroke patients without pain, and the aim was to identify whether this difference comprises the VPL and/or the VMpo.


METHODS
30 patients with chronic thalamic stroke and a persistent contralateral somatosensory syndrome were examined. CPSP patients (n=18) were compared with non-pain control patients. By coregistration of a digitised thalamic atlas with T1 weighted MR images, lesion clusters were allocated to the thalamic nuclei.


RESULTS
VPL was affected in both groups, but CPSP lesion clusters comprised the more posterior, inferior and lateral parts of the VPL compared with controls. Additional partial involvement of the VMpo was seen in only three pain patients. In three other pain patients, lesions involved neither the VPL nor the VMpo, but mainly affected the anterior pulvinar.


CONCLUSIONS
This study specifies the role of the VPL in thalamic CPSP and shows that the posterolateratal and inferior parts in particular are critically lesioned in pain patients. In this thalamic subregion, afferents of the spinothalamic tract are known to terminate. In contrast, the data do not support a pivotal impact of the VMpo on thalamic CPSP.
Centre for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Berlin, Germany. thomas.krause@charite.de
Thomas
T
Krause
Peter
P
Brunecker
Sandra
S
Pittl
Birol
B
Taskin
Dinah
D
Laubisch
Benjamin
B
Winter
Malamati Eleni
ME
Lentza
Uwe
U
Malzahn
Kersten
K
Villringer
Arno
A
Villringer
Gerhard J
GJ
Jungehulsing
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006261:Headache / Q000209:etiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging; D011446:Prospective Studies; D020886:Somatosensory Disorders / Q000209:etiology / Q000473:pathology; D020521:Stroke / Q000150:complications / Q000473:pathology*; D013786:Thalamic Diseases / Q000150:complications / Q000473:pathology*; D013788:Thalamus / Q000473:pathology*; D020651:Ventral Thalamic Nuclei / Q000473:pathology