Sulcal and ventricular trajectories in stereotactic surgery

OBJECT: The authors analyzed deep brain stimulation electrode trajectories on MR images to identify risks of cerebrovascular complications associated with the number of electrode insertions, traversal of a sulcus, and penetration of the ventricle. METHODS: Pre- and postoperative MR volumes were fused to determine the proximity of electrodes to a sulcus or ventricle and whether there were cortical, subcortical, or intraventricular complications. Complications were further classified as hemorrhagic or nonhemorrhagic and symptomatic or asymptomatic. The authors examined 258 electrode implantation for deep brain stimulation. There were 4 symptomatic events (1.6% incidence): 3 hemorrhagic and 1 nonhemorrhagic, all within the cortex. Asymptomatic events included cortical hemorrhage in 1 patient, nonhemorrhagic cortical changes in 6, pallidal hemorrhage in 1, thalamic infarction in 1, and intraventricular hemorrhage (IVH) in 5 patients. RESULTS: Proximity to a sulcus was a significant risk factor for hemorrhagic and nonhemorrhagic cortical complications (p = 0.001). There was a complication rate of 10.1% within the trajectories penetrating or adjacent to a sulcus, and a 0.7% rate with trajectories clearly positioned within the gyrus. Asymptomatic IVH was observed in 5% of ventricular penetrations. A history of hypertension was a risk factor for cortical hemorrhage (p = 0.019), but not for cortical ischemic/edematous events (p = 0.605). The number of electrode penetrations did not differ between patients with and without complications (p = 0.868), and the sequence of electrode insertions was not a risk factor in bilateral surgeries. CONCLUSIONS: Symptomatic cortical complications occur when electrodes traverse close to a sulcus. Asymptomatic IVH occurs infrequently with ventricular penetration. Despite intraoperative efforts to avoid cortical sulci, a higher than expected incidence of electrode proximity to the sulci was identified on careful postoperative trajectory analysis. This finding emphasizes the importance of assiduously planning trajectories and reviewing cases with thorough MR analysis.