Minimally invasive computer-assisted stereotactic fenestration of an aqueductal cyst: case report.

INTRODUCTION: Current advances in frame modeling and computer software allow stereotactic procedures to be performed with great accuracy and minimal risk of neural tissue or vascular injury. CASE REPORT: In this report we associate a previously described minimally invasive stereotactic technique with state-of-the-art 3D computer guidance technology to successfully treat a 55-year-old patient with an arachnoidal cyst obstructing the aqueduct of Sylvius. We provide detailed technical information and discuss how this technique deals with previous limitations for stereotactic manipulation of the aqueductal region. We further discuss current advances in neuroendoscopy for treating obstructive hydrocephalus and make comparisons with our proposed technique. CONCLUSION: We advocate that this technique is not only capable of treating this pathology but it also has the advantages to enable reestablishment of physiological CSF flow thus preventing future brainstem compression by cyst enlargement.

Influence of ischemic preconditioning in myocardial protection in patients undergoing myocardial revascularization with intermittent crossclamping of the aorta. Analysis of ions and blood gases.

OBJECTIVE: To test the hypothesis that short periods of ischemia may increase the myocardial protection obtained with intermittent crossclamping of the aorta. METHODS: In the control group (18 patients), surgery was performed with systemic hypothermia at 32 degrees C and intermittent crossclamping of the aorta. Extracorporeal circulation was used. In the preconditioning group (17 patients), 2 crossclampings of the aorta lasting 3min each were added prior to the intermittent crossclamping of the conventional technique with an interval of 2min of reperfusion between them. Blood samples for analyses of pH, pCO2, pO2, sodium, potassium, calcium, and magnesium were obtained from the coronary sinus at the beginning of extracorporeal circulation (time 1), at the end of the first anastomosis (time 2), and at the end of extracorporeal circulation (time 3). RESULTS: No difference was observed in the results of the 2 groups, except for a variation in the ionic values in the different times of blood withdrawal; sodium values, however, remained stable. All patients had a good clinical outcome. CONCLUSION: The results of intermittent crossclamping of the aorta with moderate hypothermia were not altered by the use of ischemic preconditioning.

Ischemic preconditioning in myocardial revascularization with intermittent aortic cross-clamping.

BACKGROUND: This study tests the hypothesis that initial brief periods of ischemia can increase the protection obtained by intermittent aortic cross-clamping. METHODS: In the control group (n = 18), the procedure was performed under intermittent aortic cross-clamping at 32 degrees C. Patients in the preconditioned gorup (n = 17) received a stimulus of two 3-minute periods of cross-clamping followed by 2 minutes of reperfusion prior to standard operation. CKMB, troponin 1, adenosine, and lactate were obtained from the great cardiac vein at the onset of cardiopulmonary bypass (CPB), at the end of the first anastomosis, and at the end of CPB. RESULTS: CKMB and troponin I were slightly higher at the end of CPB in the control group, while there was no difference between adenosine and lactate levels. [table: see text]. CONCLUSION: There was no difference between groups in terms of myocardial protection.