Risk factors for hemorrhage during microelectrode-guided deep brain stimulator implantation for movement disorders

OBJECTIVE: Although hemorrhage is a well-known complication of microelectrodeguided deep brain stimulation (DBS) surgery, risk factors for the development of hemorrhage have not been well defined. We analyzed the risk factors for symptomatic and asymptornatic hemorrhage in a large series of DBS implantations into the subthalamic nucleus, ventrolateral thalamus, and internal globus pallidus. METHODS: All DBS procedures performed by a single surgeon at our institution between June 1998 and May 2004 were included in this study. All patients had postoperative imaging (magnetic resonance imaging or computed tomography) 4 to 24 hours after surgery. Hematomas were noted and scored as symptomatic or asymptomatic. Statistical correlation of factors affecting risk of hematoma formation was performed by use of logistic regression analysis. RESULTS: The total number of lead implantations was 481. There were 6 symptomatic hematomas and 10 asymptornatic hematomas. Three of the symptomatic hematomas resulted in permanent new neurological deficit. The risk of hematorna (of any type) per lead implantation was 3.3%, whereas the risk of permanent deficit from hematoma was 0.6%. Patients who developed hematomas had a slightly greater number of microelectrode recording penetrations than patients who did not have hematomas, but this difference did not reach statistical significance. There was not a statistically significant relationship between risk of hematoma and patient age or diagnosis. There was a significant effect of brain target (P = 0.001), with only I hemorrhage detected after thalamic DBS. CONCLUSION: DBS is generally safe, with only 0.6% of implantations associated with permanent neurological deficit. The incremental risk of successive serial microelectrode penetrations is small.