Delayed internal capsule infarctions following radiofrequency pallidotomy. Report of three cases.

Abstract

The authors report on a series of patients with idiopathic Parkinson's disease (IPD) who underwent stereotactic radiofrequency (RF) pallidotomies, three of whom suffered delayed postoperative strokes. These three belonged to a group consisting of 42 patients with medically intractable IPD in whom 50 pallidotomies were performed. All three patients had significant previous vascular disease and were in a high-risk group for cerebral infarction. A postoperative magnetic resonance (MR) image was obtained immediately after the pallidotomy was performed to document the placement of the RF lesion and to rule out any hematoma. The delayed strokes occurred on postoperative Days 10, 51, and 117 in patients with previous vascular disease (Group 1, 11 patients). No strokes occurred in the group with the vascular disease risk factor (Group 2, 11 patients) or in the group with no risk factors for vascular disease (Group 3, 20 patients). This observation is statistically significant (p < 0.05). The T2-weighted MR images showed the lesions as high-intensity signals extending to the posterior limb of the internal capsule ipsilateral to the pallidotomy site. The poststroke T1-weighted images obtained in two patients showed persistent contrast enhancement of the RF lesion and no enhancement around the stroke lesion. Clinically and radiographically, these discrete new lesions represent delayed infarctions, 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.

AI evidence extraction

Main findings

Among 42 patients (50 pallidotomies), three patients experienced delayed postoperative strokes on Days 10, 51, and 117. The infarctions were ipsilateral to the pallidotomy site and appeared as high-intensity signals extending to the posterior limb of the internal capsule on T2-weighted MRI; authors suggest RF lesioning can induce delayed injury in adjacent tissue, particularly in patients with prior vasculopathy.

Outcomes measured

• Delayed postoperative stroke
• Internal capsule infarction (posterior limb)
• MRI findings (T1/T2 signal changes, contrast enhancement)

Limitations

• Case report/series design (no randomization)
• Small number of stroke events (n=3)
• Limited exposure characterization (no RF parameters reported)
• Potential confounding by pre-existing vascular disease

Suggested hubs

• occupational-exposure (0.1)
  Involves radiofrequency energy use, but in a neurosurgical therapeutic context rather than environmental/occupational exposure; hub relevance is weak.

{
    "study_type": "case_report",
    "exposure": {
        "band": null,
        "source": "stereotactic radiofrequency pallidotomy (RF lesioning)",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Patients with idiopathic Parkinson's disease undergoing stereotactic radiofrequency pallidotomy",
    "sample_size": 42,
    "outcomes": [
        "Delayed postoperative stroke",
        "Internal capsule infarction (posterior limb)",
        "MRI findings (T1/T2 signal changes, contrast enhancement)"
    ],
    "main_findings": "Among 42 patients (50 pallidotomies), three patients experienced delayed postoperative strokes on Days 10, 51, and 117. The infarctions were ipsilateral to the pallidotomy site and appeared as high-intensity signals extending to the posterior limb of the internal capsule on T2-weighted MRI; authors suggest RF lesioning can induce delayed injury in adjacent tissue, particularly in patients with prior vasculopathy.",
    "effect_direction": "harm",
    "limitations": [
        "Case report/series design (no randomization)",
        "Small number of stroke events (n=3)",
        "Limited exposure characterization (no RF parameters reported)",
        "Potential confounding by pre-existing vascular disease"
    ],
    "evidence_strength": "very_low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "radiofrequency pallidotomy",
        "Parkinson's disease",
        "delayed stroke",
        "internal capsule",
        "infarction",
        "MRI",
        "vasculopathy"
    ],
    "suggested_hubs": [
        {
            "slug": "occupational-exposure",
            "weight": 0.1000000000000000055511151231257827021181583404541015625,
            "reason": "Involves radiofrequency energy use, but in a neurosurgical therapeutic context rather than environmental/occupational exposure; hub relevance is weak."
        }
    ]
}

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