Abdominal x-ray and pathological findings in distal unishunt obstruction.

A new x-ray finding suggesting distal obstruction of the Unishunt is described. Fusiform swelling of the distal slit valve ("pantaloon sign") seen on an abdominal x-ray film was associated with surgically proven distal shunt obstruction in 8 of 10 patients. No patient with a normally functioning (n = 67) or proximally malfunctioning shunt (n = 6) displayed this abnormality. This finding in association with clinical and computed tomographic evidence of shunt malfunction can direct surgical revision to the appropriate site. The pathology of distal shunt malfunction is also reviewed.