CLINICAL-EXPERIENCE WITH A NEW PRESSURE-ADJUSTABLE SHUNT VALVE

The pressure-adjustable valve system Codman Medos allows valve pressur e adjustment in 18 steps between 30 and 200 mm H2O. A series of 90 pat ients, 15 children and 75 adults, who were shunted with this new progr ammable valve, is reported. Indication for shunt insertion were variou s types of hydrocephalus in 79 cases, malfunction of a medium pressure membrane valve shunt system in 9 cases and an arachnoid cyst and pseu dotumour each in one case. The valve pressure was programmed prior to insertion to 200 mm H2O in the adults and according to age in children and was modified postoperatively according to the clinical course. Un derdrainage with subdural fluid collections appearing in 5 patients co uld be managed by valve pressure adjustment alone in 2 cases. One malf unctioning of the valve mechanism was due to mechanical obstruction. A t the time of follow-up, 7 to 29 months after operation, outcome was e xcellent in 64 patients, good with marked improvement but residual sym ptoms in 19 patients and unchanged in 7 patients. The possibility of a djusting the valve pressure to the patient's demands was frequently us ed in children and adult normal pressure hydrocephalus patients with s atisfying clinical results.