DELAYED INTERNAL CAPSULE INFARCTIONS FOLLOWING RADIOFREQUENCY PALLIDOTOMY - REPORT OF 3 CASES

The authors report on a series of patients with idiopathic Parkinson's disease (IPD) who underwent stereotactic radiofrequency (RF) pallidot omies, three of whom suffered delayed postoperative strokes. These thr ee belonged to a group consisting of 42 patients with medically intrac table IPD in whom 50 pallidotomies were performed. All three patients had significant previous vascular disease and were in a high risk grou p for cerebral infarction. A postoperative magnetic resonance (MR) ima ge was obtained immediately after the pallidotomy was performed to doc ument the placement of the RF lesion and to rule out any hematoma. The delayed strokes occurred on postoperative Days 10, 51, and 117 in pat ients with previous vascular disease (Group 1, 11 patients). No stroke s occurred in the group with the vascular disease risk factor (Group 2 , 11 patients) or in the group with no risk factors for vascular disea se (Group 3, 20 patients). This observation is statistically significa nt (p < 0.05). The T-2-weighted MR images showed the lesions as high-i ntensity signals extending to the posterior limb of the internal capsu le ipsilateral to the pallidotomy site. The poststroke T-1-weighted im ages obtained in two patients showed persistent contrast enhancement o f the RF lesion and no enhancement around the stroke lesion. Clinicall y and radiographically, these discrete new lesions represent delayed i nfarctions, suggesting that RF lesioning can induce delayed injury in adjacent tissue. Patients with previously identified vasculopathy may be at risk for delayed capsular infarction following RF pallidotomy.