Occurrence of postoperative pneumoencephalus in posterior fossa surgery using the semi-sitting position: Prevalence, factors and patterns.

BACKGROUND

Posterior fossa (PF) surgery in the semi-sitting position (SSP) offers benefits for the patient, the anesthesiologist and the surgeon. However, in neurosurgery, neuroanesthesiology and related fields, a certain paradigm has been established regarding the potential high risk of this position, including the possibility of developing postoperative pneumoencephalus (PPN). The objective of the present work is to assess the prevalence, factors, and patterns related with PPN in SSP in a heterogeneous group of patients with PF conditions.

METHODS

Observational, descriptive, cross-sectional study with prospective data collection. Was conducted in two institutions. January 2020 and June 2023. 192 patients with intradural PF pathology operated on in the SSP were included.

RESULTS

In most patients (93.2%; n:179) PPN was observed on postoperative CT. The most frequent pattern of PPN was subdural. No patient (0%; n:0) developed tension PPN, so none required surgery. A significant association was found between subdural PPN and operating time. We found a higher presence of PPN in patients with an age range of 40-60 years and in the group of patients>60 years.

CONCLUSIONS

The majority of patients in our series presented PPN. The most frequent pattern was subdural. There was an association between operating time and subdural PPN. There was an association between the older patient groups and PPN. No patient presented tension PPN.