Evaluation of back pain secondary to spinal epidural hematoma associated with aspirin intake and a partial platelet glycoprotein Ia/IIa deficiency.

We report a case of spontaneous spinal epidural hemorrhage with three unusual features: (1) the hemorrhage was associated with aspirin ingestion and a reduced level of platelet glycoprotein Ia/IIa; (2) the patient presented with typical severe back pain but without neurologic dysfunction; and (3) the patient initially recovered without surgical decompression but suffered from recurrent epidural hematoma.

Recurrence of cervical artery dissection. A prospective study of 81 patients.

BACKGROUND AND PURPOSE: Spontaneous cervical artery dissection (SCAD) is a common cause of stroke in the young; however, its recurrence has been rarely studied. Recurrent SCAD at the level of the previously dissected vessel has been reported in only six patients. METHODS: We prospectively evaluated and followed a series of 81 patients seen in our center with carotid (n = 66) or vertebral (n = 15) artery dissection, in whom the diagnosis was confirmed by angiography, MRI, or both. Repeated clinical and ultrasound examinations were performed in all patients during a mean follow-up of 34 months (range, 12 to 57 months). RESULTS: Three patients died of the consequences of stroke, and four patients were unavailable for follow-up. Three of the remaining 74 patients (4%) had a recurrent carotid dissection while under prophylaxis with aspirin (n = 2) or anticoagulation (n = 1). None of the patients had a recurrent vertebral dissection. Recurrent carotid dissection occurred 16 months to 4 years after the first episode and presented with acute head and neck pain (n = 2) and hemispheric transient ischemic attack (n = 1). In one patient recurrence was documented by Doppler and MRI at the level of the first dissection. CONCLUSIONS: We confirm that recurrence of SCAD is uncommon and usually represents a benign condition. Delayed recurrence seems to be more common than previously suggested and can occur at the level of the previously dissected vessel.

Accuracy of MRI-guided stereotactic thalamic functional neurosurgery.

Our goal was to evaluate the accuracy of stereotactic technique using MRI in thalamic functional neurosurgery. A phantom study was designed to estimate errors due to MRI distortion. Stereotactic mechanical accuracy was assessed with the Suetens-Gybels-Vandermeulen (SGV) angiographic localiser. Three-dimensional MRI reconstructions of 86 therapeutic lesions were performed. Their co-ordinates were corrected from adjustments based on peroperative electrophysiological data and compared to those planned. MR image distortion (maximum: 1 mm) and chemical shift of petroleum oil-filled localiser rods (2.2 mm) induced an anterior target displacement of 2.6 mm (at a field strength of 1.5 T, frequency encoding bandwidth of 187.7 kHz, on T1-weighted images). The average absolute error of the stereotactic material was 0.7 mm for anteroposterior (AP), 0.5 mm for mediolateral (ML) and 0.8 mm for dorsoventral (DV) co-ordinates (maximal absolute errors: 1.6 mm, 2.2 mm and 1.7 mm, respectively; mean euclidean error: 1 mm). Three-dimensional MRI reconstructions showed an average absolute error of 0.8 mm, 0.9 mm and 1.9 mm in AP, ML and DV co-ordinates, respectively (maximal absolute errors: 2.4 mm, 2.7 mm and 5.7 mm, respectively; mean euclidean error: 2.3 mm). MRI distortion and chemical-shift errors must be determined by a phantom study and then compensated for. The most likely explanation for an average absolute error of 1.9 mm in the DV plane is displacement of the brain under the pressure of the penetrating electrode. When this displacement is corrected for by microelectrode recordings and stimulation data, MRI offers a high degree of accuracy and reliability for thalamic stereotaxy.