title: Quantitative analysis of adverse events in neurosurgery.
abstract: OBJECTIVE
  : It is well recognized that the occurrence rate of adverse events related to surgical procedures is considerably high in neurosurgery compared with other specialties. The purpose of this study was to quantitatively determine the occurrence rate of adverse events related to surgery and endovascular intervention in neurosurgery.
  
  
  METHODS
  A conference on adverse events related to treatments (morbidity and mortality conference) has been held every month for the past 2 years in our department. At these conferences, all adverse events are evaluated and discussed. Adverse events include not only the unexpected complications, but also the neurological and general deterioration predicted before surgery. All the adverse events are discussed in terms of the conceivable causes, their association with the procedures, and the possibility of prediction and avoidance.
  
  
  RESULTS
  One hundred eighty-two events (28.3%) among 643 neurosurgical interventions over 2 years were recognized as adverse events. Among these 182 adverse events, 165 (90.7%) were closely related to procedures and 125 events (68.7%) were predictable before or during the procedures. However, even when retrospectively reviewed, only 6 (3.3%) of events were deemed avoidable. Of these 6 avoidable events, there were only 2 (1.1%) that were considered to have been caused by error.
  
  
  CONCLUSIONS
  Adverse events are not invariably rare in neurosurgery. Most of them are predictable; however, their avoidance is not necessarily easy. Avoidable adverse events caused by medical errors were observed in only 1.1% of cases.
authors.affiliation: Department of Neurosurgery, Sapporo Medical University, Sapporo, Japan. houkin@sapmed.ac.jp
authors.forename: Kiyohiro
authors.initials: K
authors.lastname: Houkin
authors.forename: Takeo
authors.initials: T
authors.lastname: Baba
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Minamida
authors.forename: Tadashi
authors.initials: T
authors.lastname: Nonaka
authors.forename: Izumi
authors.initials: I
authors.lastname: Koyanagi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Iiboshi
mesh_terms: D016208:Databases, Factual / Q000706:statistics & numerical data; D006801:Humans; D019300:Medical Errors; D009017:Morbidity; D019635:Neurosurgical Procedures / Q000009:adverse effects*; D011183:Postoperative Complications / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology* / Q000401:mortality; D011787:Quality of Health Care; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D013223:Statistics as Topic