Hygromas after endoscopic third ventriculostomy in the first year of life: incidence, management and outcome in a series of 34 patients.

BACKGROUND: Overdrainage in shunted patients is a known predisposing factor for the formation of hygromas, but little is known about risk factors in endoscopic third ventriculocisternostomy (ETV).

MATERIALS AND METHODS: We retrospectively analysed data of 34 patients younger than 1 year with obstructive hydrocephalus, undergoing ETV, with respect to incidence, management, outcome and possible risk factors for the formation of hygromas. Hygromas were arbitrarily defined as a collection of cerebrospinal fluid of more than 10 mm in diameter over the paramedian hemispheric convexities, diagnosed by ultrasonography.

RESULTS: They occurred in 9 of 34 (26%) patients 3 to 28 days after ETV. They were on the operated side in four and bi-lateral in five cases. There was no relevant age difference between patients with hygromas (median 127 days) and those without hygromas (median 166 days). Etiology of obstructive hydrocephalus had no impact on the frequency of hygromas. Hygromas occurred somewhat less frequently when a paediatric endoscope with an outer diameter of 3 mm was used for ETV instead of an endoscope with a diameter of 6 mm. Hygromas were asymptomatic and conservatively managed in five cases; 4 of 34 (12%) patients underwent surgery because of clinical symptoms of increasing intracranial pressure or increasing hygroma diameter. Two patients were treated with a temporary external drainage only and another two patients with an external drainage first and eventually a subduro-peritoneal shunt. There were no neurological long-term sequelae.

CONCLUSION: Clear predisposing factors for the formation of hygromas could not be identified, but the outer diameter of the endoscope may play a role.