Lacunar Infarction Caused by Chronic Subdural Hematoma

In chronic subdural hematoma (CSDH) patients, motor functions usually recover quickly after burr-hole surgery; however, in a rare case, the hemiparesis showed poor improvement after surgery. In that case, investigation of cerebral infarctions is important. Among the 284 CSDH patients with motor weakness, magnetic resonance image (MRI) and MR angiography (MRA) were acquired in 82 patients before surgery when the hemiparesis progressed rapidly. Small lacunar infarction was identified on the hematoma side in five cases; all were older than 80 years with hypertension, and diabetes mellitus had been diagnosed in two. In all the five patients (100%), MRA demonstrated a downward or upward shift of the M1 portion of the middle cerebral artery on the hematoma side, where the perforating arteries originate. Conversely, only 4 CSDH patients (5.2%) without lacunar infarction demonstrated M1 downward shift. The risk factors of lacunar infarction were high in the five detected cases; however, distortion, twisting, or elongation of the lenticulostriate arteries might be a cause of the lacunar infarctions, rather than the formation of lipohyalinosis or microatheroma in the arteries. Therefore, anti-platelet treatment might not be necessary for CSDH-inducing lacunar infarction. The lacunar infarctions caused by CSDH were small, the patients' hemiparesis was mild, a prognosis of all the patients was good, and they recovered well from the motor weakness after physical rehabilitation. MR examinations before surgery are recommended for CSDH patients especially when a patient complains of sudden onset or rapid deterioration of motor weakness.