Research Article: Risk factors for postoperative meningitis after microsurgery for vestibular schwannoma

Date Published: July 5, 2019

Publisher: Public Library of Science

Author(s): Bowen Huang, Yanming Ren, Chenghong Wang, Zhigang Lan, Xuhui Hui, Wenke Liu, Yuekang Zhang, Jonathan H. Sherman.


Meningitis after microsurgery for vestibular schwannoma (VS) is a severe complication that results in high morbidity. However, few studies have focused on meningitis after VS surgery. The purpose of this study was to identify the risk factors for meningitis after VS surgery.

We performed a retrospective analysis of all VS patients who underwent microsurgery and survived for at least 7 days after surgery, between 1 June 2015 and 30 November 2018 at West China Hospital of Sichuan University. Univariate and multivariate analyses were performed to identify the risk factors for postoperative meningitis (POM).

We enrolled 410 patients, 27 of whom had POM. Through univariate analysis, the factors of hydrocephalus (p = 0.018), Koos grade IV (p = 0.04), operative duration > 3 hours (p = 0.03) and intraoperative bleeding volume ≥400 ml (p = 0. 02) were significantly correlated with POM. The multivariate analysis showed that Koos grade IV (p = 0.04; OR = 3.19; 95% CI 1.032–3.190), operation duration > 3 hours (p = 0.03; OR = 7.927; 95% CI 1.043–60.265), and intraoperative bleeding volume ≥ 400 ml (p = 0.02; OR = 2.551; 95% CI 1.112–5.850) were the independent influencing factors of POM.

Koos grade IV, operation duration > 3 hours, and intraoperative blood loss ≥ 400 ml were identified as independent risk factors for POM after microsurgery for VS. POM also caused a prolonged hospital stay.

Partial Text

Vestibular schwannoma (VS), also referred to as acoustic neuroma (AN), is a histopathologically benign tumor arising from Schwann cells surrounding the vestibular nerve[1]. The incidence of VS is estimated to be 1.9 per 100,000 per year[2]. Microsurgical resection is typically the gold standard of treatment for symptomatic, relatively young patients[3]. With the rapid development of minimally invasive neurosurgical technology and electrophysiological monitoring, the surgical mortality has significantly decreased[4]. However, the frequency of postoperative complications remains high. Meningitis is the main fatal complication after craniocerebral surgery. In addition, the data show that the incidence of postoperative meningitis (POM) following vestibular schwannoma surgery is approximately 5.5%-9.85%[4–8]. In the event of POM, the mortality can be as high as 50%[9]. However, related research on the clinical risk factors of meningitis after acoustic neuroma surgery is limited.

Meningitis is divided into aseptic meningitis and bacterial meningitis. According to a previous study, the positive rate of CSF culture is approximately 33%[11, 12]. However, in these meningitis patients, no bacteria were cultured in the CSF cultures, which may be due to the intraoperative prophylactic administration of an antibiotic and the prophylactic administration of antibiotics in the case of symptoms or signs of postoperative infection. The positive rate of CSF or blood culture decreases significantly if antibiotics are used for more than 24 hours before diagnosis[13]. In another study, the positive rate of CSF culture in their meningitis patients was also low, at 3.48% [4]. The culturing results may be negative, but many cases of culture-negative (aseptic) meningitis are bacterial meningitis[14]. In the future, we can try to improve the positive rate of CSF culture by some more sensitive methods, such as polymerase chain reaction techniques[14]. In this study, the incidence of meningitis after microsurgery of vestibular schwannoma was less than 6.6%, which is lower than the results reported by Huang Xiang. In their research, the incidence of meningitis after microsurgery of vestibular schwannoma is 9.85% [4]. What makes the results of the two studies inconsistent with each are the following observations. First, 8% of our patients had a tumor with a volume smaller than 30 x 20 mm. Second, we routinely used glucocorticoids intraoperatively and postoperatively to reduce cerebral edema and to suppress inflammatory responses. Through our data analysis, Koos grade, the duration of surgery and intraoperative blood loss were observed to be significant factors in the development of meningitis after microsurgery for vestibular schwannoma. In addition, POM significantly prolongs the length of hospital stay.

In this study, the probability of meningitis after acoustic neuroma microsurgery was 6.6%. The risk factors of meningitis after microsurgery are Koos grade IV, operation duration >3 hours, and intraoperative bleeding volume ≥ 400 ml. In addition, POM has a significant association with an increase in hospitalization days after operation. Therefore, to prevent POM, TXA administration and preoperative embolization may be effective methods in the future.




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