Deep brain stimulation in intraoperative MRI environment - comparison of imaging techniques and electrode fixation methods.

We performed 118 consecutive DBS cases from November 1999 to June 2002. Intraoperatively there were 10 cases studied with fluoroscopy, 73 with 0.2 Tesla (T) MRI and 35 with 1.5 T MRI. Ten electrodes were secured by Medtronic caps, 25 by methyl methacrylate with titanium miniplates, and 82 by Navigus caps. The 3-dimensional displacement between the planned target and actual electrode position (3DD) was determined by fusing the postoperative MRI with the preoperative imaging. The 3DD for using Medtronic caps, methyl methacrylate with miniplates, and Navigus caps were 4.80 +/- 3.16, 2.64 +/- 1.26 and 2.23 +/- 1.15 mm (mean +/- SD), respectively. Navigus caps had statistically significant accuracy (P = 0.03) in holding the electrode when compared with Medtronic caps, and it facilitated electrode revision. The fixation devices significantly affect the final vertical position of the electrode. The 3DD for fluoroscopy, 0.2 T and 1.5 T MRI cases were 4.80 +/- 3.16, 2.31 +/- 1.21 and 2.34 +/- 1.14 mm (mean +/- SD), respectively. No statistically significant difference (P = 0.91) in 3DD was demonstrated between 0.2 T and 1.5 T MRI cases. The presence of intraoperative 1.5 T MRI allowed near real-time electrode position confirmation and early detection of hemorrhagic complications. Satisfactory microelectrode recording was feasible in low-field 0.2 T and high-field 1.5 T MRI environments. Further studies on performing DBS in real-time intraoperative MRI are warranted.

Outcome analysis of intraventricular thrombolytic therapy for intraventricular haemorrhage.

OBJECTIVES: To evaluate the outcome of intraventricular thrombolytic therapy for intraventricular haemorrhage and to formulate a safe and effective regimen. DESIGN: Retrospective study. SETTING: Regional neurosurgical centre, Hong Kong. PATIENTS: Twenty-nine consecutive adult patients who presented from November 1995 to November 1998 with non-traumatic intraventricular haemorrhage (Graeb score, > or =7) with no active rebleeding risks from vascular abnormalities. INTERVENTIONS: Fourteen consecutive patients received intraventricular streptokinase via the external ventricular drainage, and 15 consecutive patients received intraventricular urokinase treatment. MAIN OUTCOME MEASURES: Patient demographics, Glasgow coma scale score, Graeb score, mortality rate, shunt rate, fever response, infection rate, catheter blockage rate, and local and systemic bleeding tendency. RESULT: The mean age of the 16 men and 13 women was 59 years (range, 14-76 years). The median Graeb score for cases of intraventricular haemorrhage was 10 (range, 7-12). There was no significant difference in terms of the Graeb score distribution, total dosage, and duration of treatment between the streptokinase and urokinase groups. More cases of fever were observed in the streptokinase group, which could be due to its antigenicity. The infection rate of the central nervous system was 3%, and the shunt rate was 24%. The overall 1-month postoperative mortality was 10%, which was related to a low preoperative Glasgow coma scale score (< or =4). No local rebleeding, systemic coagulopathy, or catheter blockage occurred. CONCLUSIONS: Intraventricular thrombolytic therapy is a safe and effective method of managing intraventricular haemorrhage. We suggest instilling 20 000 units urokinase intra-operatively, followed by 20 000 units daily for about 3 days, except in cases of vascular abnormality, bleeding tendency, and trauma.