Infections in neurosurgery: a retrospective study of 1143 patients and 1517 operations.

The files of 1143 neurosurgical patients, operated on between November 1, 1979 and June 4, 1981 were examined for records of post-operative infections. Eighty-three patients had developed infections (7%). In addition there were 33 instances of aseptic meningitis. Patients with a shunt were prone to infection (12%). Bone flap infections accounted for more than half of all infections after supratentorial craniotomy. Bacterial meningitis accounted for more than half of all infections after suboccipital craniotomy and translabyrinthine operations. In these patients bacterial meningitis was six times more common, and aseptic meningitis three times more common than in those who had had supratentorial operations. Shunt infection was more common after repeated shunt operations in quick succession. Craniotomy increased the risk of a shunt becoming infected. Antibiotic prophylaxis should be used not only in shunt operations but in all operations performed on patients with a shunt. If bacteria are recovered in a suspected shunt infection, immediate removal of the shunt is the best treatment. However, if the shunt's removal or replacement is exceptionally difficult intraventricular antibiotic treatment may be tried. The age of the patient, the duration of the operation, the individual surgeon and the number of operations did not affect the rate of infection. Clinical signs and conventional laboratory tests, apart from bacterial culture, cannot differentiate between bacterial and aseptic meningitis, but a drop in the level of consciousness suggests bacterial meningitis.