Use of the distal double-slit valve system in children with hydrocephalus.

Shunts with distal slit valves have been in use for almost three decades for children with hydrocephalus. Drawbacks of this device include shunt obstruction, infection and overdrainage. One-piece shunts have been used widely for ventriculoperitoneal insertion because they are easy to place, do not need manipulation of connecting parts during surgery, and rarely disconnect. Disadvantages of these shunts, however, include a relatively higher risk of distal obstruction than with the open-ended peritoneal tube and a tendency for overdrainage. With these disadvantages in mind, we hypothesized that using double-distal-slit valves could increase the survival rate of the shunt. For the past 2 years we have been using a one-piece shunt with double-distal-slit valves and an elliptical reservoir under a strict protocol. The study showed the following (1) Among the children operated on, 30.3% required shunt revisions (0.9 revisions per patient). Children with intraventricular hemorrhage-posthermorrhagic hydrocephalus had a three times higher risk of shunt revision than children with posttraumatic hydrocephalus (55.4% vs 18.8%). (2) The so-called slit-ventricle syndrome was observed in only 4 children (8.5%), who subsequently required surgical attention. Most of the children with other forms of the overdrainage phenomenon continued to do well without clinical problems. (3) Of the 155 children, 7 (4.5%) experienced infections after the initial shunt installation. (4) Of the 136 shunt revisions, 90.4% (123 procedures) were related to obstruction. Distal obstruction (47.1%) was more frequent than proximal obstruction (36.6%). (5) In 8 children, the shunt was still working through the proximal set of valves when the distal set of valves was completely obstructed.(ABSTRACT TRUNCATED AT 250 WORDS)