Experience with the Strata valve in the management of shunt overdrainage

Object. The overdrainage of cerebrospinal fluid (CSF) in children with shunt-treated hydrocephalus may cause chronic disabling symptoms and require repeated surgery. Externally adjustable valves offer a noninvasive way of altering the valve opening pressure. The authors report on their experience with using the Strata valve in the management of symptomatic CSF overdrainage. Methods. The authors treated 24 patients with symptomatic CSF overdrainage by inserting a Strata valve. The severity of symptoms was graded, and the frequency of hospital visits and shunt operations was recorded before and after insertion of the valve. Additionally, results of brain imaging and intracranial pressure monitoring were reviewed. Nineteen patients (79.2%) had severe symptoms at the time of the insertion; I year after Strata valve insertion only one patient (4.17%) still suffered severe symptoms. The number of hospital admissions was 3.38/patient/year before placement and 1.21 for the 1 st year, 1 for the 2nd, and 0.4 for the 3rd postoperative year. The number of operations was 3.42/patient/year during the year before placement of the valve, and then 0.71 for the 1 st, 0.56 for the 2nd, and 0.25 for the 3rd postoperative years. During the I st year after placement of the Strata valve, the settings were changed 2.79 times/patient/year, 1.29 for the 2nd, and 1.33 times/patient/year for the 3rd year. Conclusions. The Strata valve was effective in improving the symptoms of overdrainage in the majority of patients in this series. The number of hospital admissions and operations for valve malfunction was reduced.