EXPERIENCES WITH FLOW REGULATED SHUNTS (ORBIS-SIGMA VALVES) IN CASES OF DIFFICULTY IN MANAGING HYDROCEPHALUS IN CHILDREN

Due to an increasing number of shunt complications with conventional v alves, we performed a study of 80 flow-regulated Orbis-Sigma valves im planted in 47 children who had had repeated complications with convent ional valves and 33 children receiving their first shunt. The results were encouraging. During the first 5 years after implantation, the pro bability of absence of any kind of surgical intervention to the valve system was 57% and the probability satisfactory function of the valve itself was 70%. The most frequent complication was underdrainage of CS F, especially in children under the age of 1 year. No cases of CSF ove rdrainage occurred in this series. The Orbis-Sigma valve appears espec ially useful for patients unable to tolerate the anti-siphon device, a nd for patients over 1 year old receiving their first valve for hydroc ephalus of non-tumoral and non-haemorrhagic origin.