[Preoperative adverse events during stereotactic microelectrode-guided deep brain surgery in Parkinson's disease]

To evaluate the prevalence of adverse events and complications during surgery using deep brain electrodes, mainly in the treatment of Parkinsonism. To describe the adjustment of propofol to meet the needs of neurophysiological monitoring.

A prospective study of patients undergoing stereotactic microelectrode-guided deep brain surgery (stereotactic pallidotomy, implantation of electrodes in the thalamic or subthalamic neurons of the globus pallidus). After placement of a stereotactic frame and completion of a computed tomography scan of the head, the patients were transferred to the operating room. Monitoring included electrocardiography, pulse oximetry, arterial pressure (invasive), endtidal carbon dioxide pressure, and diuresis. Anesthesia was maintained by intermittent infusion of propofol. Variables recorded were age, sex, disease and time elapsed since diagnosis, surgical complications and their treatment, total dose of propofol, duration of surgery, and place of transfer for recovery.

One hundred twenty-eight patients (50 women, 78 men) with a mean (+/- SD) age of 59.6 +/- 10.2 years underwent the procedure from 1996 through 2003. The mean time elapsed since diagnosis of the disease was 14 +/- 6.2 years. The propofol dose was 890.6 +/- 571.4 mg and duration of surgery was 8.3 +/- 2.4 hours. Adverse events were observed for 101 patients (78.9%). The most common complications involved hemodynamics: arterial hypertension (59.4%), bradycardia (18.0%), arterial hypotension (7.9%), and tachycardia (6.2%). Other more serious complications were pneumocephalus with clinical repercussions (3 cases), globus pallidus hematoma (2), air embolism (2), epileptic seizure (3), anisocoria (1), and dyspnea and/or airway obstruction (7).

Deep brain stimulation requires surgery of long duration. Because of frequent episodes of arterial hypertension, which increases the risk of brain hemorrhage, and other less common but potentially dangerous complications, careful clinical monitoring is necessary during the procedure. The intermittent use of propofol does not interfere with neurophysiological monitoring.