[Dissociative sensory disturbance after removal of an arteriovenous malformation in the posterior thalamic region].

A 34-year-old male developed consciousness disturbance; semicoma, on December 15, 1984, and diagnosed as a thalamic hemorrhage perforating into the ventricular system after a computed tomographical (CT) examination. Angiography revealed an arteriovenous malformation (AVM) in the right posterior thalamic region, which was fed by a posteromedial choroidal artery. He was transferred to our neurosurgical clinic on February 18, 1985. On admission, he was alert, however, disorientation and slight mental retardation were seen as well as Parinaud's sign. Mild left hemiparesis was also detected with equivocal hypesthesia on the left lower limb. The AVM was subtotally removed on March, 12, via transventricular approach after right parietooccipital craniotomy. Consciousness disturbance (drowsy) and left hemiplegia developed after the operation, however, these deteriorations were transient, recovering to the preoperative or better status by 2 weeks after the operation. Postoperative repetitive examinations of the sensory perceptibility of various modalities revealed remarkable disturbance or complete loss of perception in joint and vibration senses (0-3/10 compared to the healthy left side). Touch sensation was also severely deteriorated (0-3/10) on the affected extremities. The disturbances in these modalities of the sensation did not show any trend to improve until the time of discharge on 57th postoperative day. On the other hand, pain and temperature sensations were less remarkably disturbed (5-8/10), and with tendency of gradual improvement. Estimation of the range of lesion by the CT scan with projecting on the Schaltenbrand & Bailey's atlas revealed that the nucleus ventralis caudalis, centre-median nucleus and pulvinar thalami were involved.(ABSTRACT TRUNCATED AT 250 WORDS)