title: Reducing hemorrhagic complications in functional neurosurgery: a large case series and systematic literature review.
abstract: OBJECTIVE
  Hemorrhagic complications carry by far the highest risk of devastating neurological outcome in functional neurosurgery. Literature published over the past 10 years suggests that hemorrhage, although relatively rare, remains a significant problem. Estimating the true incidence of and risk factors for hemorrhage in functional neurosurgery is a challenging issue.
  
  
  METHODS
  The authors analyzed the hemorrhage rate in a consecutive series of 214 patients undergoing image-guided deep brain stimulation (DBS) lead placement without microelectrode recording (MER) and with routine postoperative MR imaging lead verification. They also conducted a systematic review of the literature on stereotactic ablative surgery and DBS over a 10-year period to determine the incidence and risk factors for hemorrhage as a complication of functional neurosurgery.
  
  
  RESULTS
  The total incidence of hemorrhage in our series of image-guided DBS was 0.9%: asymptomatic in 0.5%, symptomatic in 0.5%, and causing permanent deficit in 0.0% of patients. Weighted means calculated from the literature review suggest that the overall incidence of hemorrhage in functional neurosurgery is 5.0%, with asymptomatic hemorrhage occurring in 1.9% of patients, symptomatic hemorrhage in 2.1% and hemorrhage resulting in permanent deficit or death in 1.1%. Hypertension and age were the most important patient-related factors associated with an increased risk of hemorrhage. Risk factors related to surgical technique included use of MER, number of MER penetrations, as well as sulcal or ventricular involvement by the trajectory. The incidence of hemorrhage in studies adopting an image-guided and image-verified approach without MER was significantly lower than that reported with other operative techniques (p < 0.001 for total number of hemorrhages, p < 0.001 for asymptomatic hemorrhage, p < 0.004 for symptomatic hemorrhage, and p = 0.001 for hemorrhage leading to permanent deficit; Fisher exact test).
  
  
  CONCLUSIONS
  Age and a history of hypertension are associated with an increased risk of hemorrhage in functional neurosurgery. Surgical factors that increase the risk of hemorrhage include the use of MER and sulcal or ventricular incursion. The meticulous use of neuroimaging-both in planning the trajectory and for target verification-can avoid all of these surgery-related risk factors and appears to carry a significantly lower risk of hemorrhage and associated permanent deficit.
authors: Unit of Functional Neurosurgery, Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, UK. l.zrinzo@ucl.ac.uk
authors: Ludvic
authors: L
authors: Zrinzo
authors: Thomas
authors: T
authors: Foltynie
authors: Patricia
authors: P
authors: Limousin
authors: Marwan I
authors: MI
authors: Hariz
mesh_terms: D001921:Brain / Q000601:surgery*; D002543:Cerebral Hemorrhage / Q000209:etiology* / Q000517:prevention & control*; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000601:surgery; D019635:Neurosurgical Procedures / Q000009:adverse effects*; D012307:Risk Factors