Tension pneumocephalus following suboccipital sitting craniotomy in the pediatric population.

Background: Sitting craniotomy often results in entrapment of air in fluid-filled intracranial cavities. Gas under pressure exerts a deleterious effect on adjacent nervous tissue, resulting in clinical deterioration.

Aim Of Study: To assess the incidence of tension pneumocephalus (TP) and to define risk factors associated therewith.

Material And Method: Analysis included 100 consecutive patients (57 boys, 43 girls, mean age 9.7 y) undergoing suboccipital sitting craniotomy since 2012 to 2014.

Results: In our material (n=100) TP was seen in 7 cases, asymptomatic pneumocephalus (AP) in 77 and no pneumocephalus (NP) in 16. Tumor types encountered were typical for pediatric population. In the TP group (n=7) the ratio of low-grade to high-grade tumors was 5:2, in the AP group (n=77) 2:1 and in the NP group (n=16) 1:1. Preoperative hydrocephalus was present in 21 cases (21%, mean incidence), thereof 3 in the TP group (3/7; 42.8%), 12 in AP group (12/77; 15.5%) and 6 in the NP group (6/16; 37.5%). All TP patients received an emergency external drainage, thereof 4 required a permanent ventriculo-peritoneal shunt (57.1%), while AP and NP patients combined (n=93) required a permanent shunt in 4 cases only (4.3%). TP-associated morbidity (n=2) consisted in a significant deterioration of neurological condition.

Conclusions: TP is a relatively rare but potentially serious complication of suboccipital sitting craniotomy. Risk factors for TP are low-grade tumor and pre-existing long-standing hydrocephalus. TP requires emergency decompression by temporary external drainage. TP patients significantly more often require a permanent CSF shunt.