[Our experience with the programmable Codman-Medos valve: review of 125 shunts]

Programmable valves are a possible solution in cases of excessive or insufficient draining.

To report our experience with these shunts and clarify concepts.

We have implanted 125 Codman-Medos programmable devices in 118 patients. The most frequent indication was secondary hydrocephalus, particularly due to obstruction by a tumour, and primary hydrocephalus. They were also used in cases of benign intracranial hypertension, CSF fistulas and arachnoid cysts. Most valves were inserted frontally, under antibiotic prophylaxis.

Excluding patients with a follow-up of less than three months, the average follow-up was 14.63 +/- 9.07 months, with clinical improvement in 80%. There was 0% mortality in relation to surgery. The initial average pressure was 121.84 +/- 24.74 mmH2O and after 52 reprogrammings done in 36 (30%) of the patients, the final average pressure was 124.96 +/- 30.58 mmH2O. Reprogramming was done for the management of symptoms and to avoid subdural hygromas. We have observed no clinical signs of unprogramming. There were 29 complications which were treated by reprogramming in 7 cases and surgically in the remainder.

We recommend frontal insertion, with a long peritoneal catheter, mainly in patients with hydrocephalus secondary to stenosis of the aqueduct of Sylvius, benign intracranial hypertension, after head injury and Arnold-Chiari malformation. The initial pressure is difficult to determine but tends to be average or high. Reprogramming is particularly useful in the treatment of subdural hygromas. We have observed no clinical signs of unprogramming. Complications tend to be due to surgical technique rather than the particular shunt used.