Influencing factors of intracranial infection and risk prediction analysis after neurosurgical operation

Objectives To analyze the incidence, risk factors of intracranial infection after neurosurgical operation and to propose a prediction score scale based on these risk factors. Methods New prophylactic strategy of antibiotics (timing: 0.5-2 h ahead of neurosurgical procedures; duration: 24 hours for type Ⅰ incision and 48 hours for type Ⅱ incision) was used in 2012, and 2 058 patients from August to October were chosen for analysis. Based on the independent risk factors identified by logistic regression, a score scale was proposed to stratify patients into high-risk or low-risk group for postoperative intracranial infection. Results The incidence of intracranial infection for type Ⅰ and type Ⅱ incision was 10.1% (115/1 137) and 11.0% (101/921), respectively. Logistic regression revealed that younger patients, longer operative duration, and lesion in the posterior fossa or the ventricles were independent risk factors for postoperative intracranial infection. Compared with the patients aged 17-40, the ORs (95% CI) of intracranial infection in patients aged 40-60 and ≥60 were 0.546 (0.401 - 0.745) and 0.277 (0.153 - 0.499), respectively. Compared with the lesions in the sellar region, the ORs (95% CI) of intracranial infection for lesion in the supratentorial region, spinal canal, brainstem/cerebellopontine angle/cerebellum, and the ventricle were 3.014 (1.329 - 6.838), 1.977 (0.855-4.571), 4.585 (1.971 - 10.666), and 8.410 (2.924 - 24.195), respectively. Compared with operative duration <4 h, the ORs (95%CI) of intracranial infection for 4-7 h and ≥7 h were 4.555 (2.280 - 9.100) and 8.939 (4.292 - 18.615), respectively. On ROC curve, the cutoff score to predict intracranial infection for type Ⅰ and type Ⅱ incision was -2.2 and -1.9, respectively. For type Ⅰ incision, the frequencies of intracranial infection in low-risk (<-2.2) and high-risk (≥-2.2) groups were 4.4%(30/685) and 18.8%(85/452), respctively. For type Ⅱ incision, the frequencies of intracranial infection in low-risk (<-1.9) and high-risk (≥-1.9) groups were 3.1%(18/588) and 24.9%(83/333), respectively. Conclusions Younger age, longer operative duration and lesions in the posterior fossa or the ventricle were independent risk factors for postoperative intracranial infection. The prediction score scale could be effectively used to stratify patients into high-risk or low-risk group for postoperative intracranial infection, which provided the basis for individualized prophylactic strategies of antibiotics. Key words: Central nervous system bacterial infections; Neurosurgical procedures; Risk factors; Prediction