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

OBJECTIVE: Although hemorrhage is a well-known complication of microelectrode-guided 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 asymptomatic 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 asymptomatic hematomas. Three of the symptomatic hematomas resulted in permanent new neurological deficit. The risk of hematoma (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 1 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.