Incidence, Characteristics, and Outcomes of Pseudomeningocele and Cerebrospinal Fluid Fistula after Posterior Fossa Surgery.

OBJECTIVE: Posterior fossa approaches are common neurosurgical procedures. Rates of postoperative infection, pseudomeningocele, and cerebrospinal fluid (CSF) fistula are high; however, evidence regarding predisposing risk factors and treatment outcomes remain sparse. METHODS: A retrospective cohort study was carried out of all posterior fossa surgeries conducted at a single institution between January 2015 and October 2019. Univariate statistical methods and stepwise logistic regression were used to assess which factors contributed most to risk of development of postoperative complications. RESULTS: A total of 269 patients were included; 18.6% experienced any postoperative complication, 13% developed either pseudomeningocele or CSF fistula, and 9.7% developed an infection. In multivariate analysis, development of a pseudomeningocele was significantly associated with previous cranial surgery (hazard ratio [HR], 3.15; 95% confidence interval [CI], 1.12-9.28; P = 0.0391). Development of a CSF fistula was significantly associated with index surgery for resection of neoplasm (HR, 7.65; 95% CI, 1.86-22.31; P = 0.0174). Development of an infection was significantly associated with concurrent CSF fistula (HR, 7.16; 95% CI, 1.91-23.19; P = 0.0041) and concurrent pseudomeningocele (HR, 3.41; 95% CI, 1.37-5.95; P = 0.0082) and nonsignificantly associated with diabetes requiring treatment (HR, 2.42; 95% CI, 0.69-8.50; P = 0.168). Other hypothesized risk factors for these complications, such as nonmidline approaches to the posterior fossa, watertight duraplasty, use of dural fibrin sealant, and cranioplasty were not associated with these complications on multivariate analysis. Although many patients with pseudomeningocele were successfully managed with observation, only 38% of patients in whom CSF diversion was attempted avoided surgery. CONCLUSIONS: History of diabetes, cranioplasty, revision surgery, and surgery for tumor resection are identified as risk factors for the development of infection, pseudomeningocele, and CSF fistula, respectively.