gms | German Medical Science

Background: In 1973 Portnoy and Schulte developed the antisiphon-device for the prevention of overdrainage, a supplementary valve with a variable resistance depending of body verticalization respect. the variable suction of the water column in the distal catheter. Clones were the SCD (PS-Medical) and SLD (Radionics). All were assembled to other DP-valves or integrated in bodies combined with conventional valves (Delta, Novus).

Unfortunately many cases with enigmatous hydraulic problems, especially underdrainage, but also overdrainage were observed. In 1989 we identified the cause, the excessive susceptibility on external pressure, e.g. scars. For the compensation of these disturbing influences some users combined the antisiphons with adjustable Sophy- or Medos-valves. Unfortunately evaluations of these combinations, which anticipated the later Strata-valve, were not published. Generally long-term results of antisiphons are rarities.

Patients and Methods:We evaluated retrospectively 37 patients with antisiphons 4-22 years after implantation, of them 18 with adjustable main valves. 5 had telemetric ICP sensors.

Results: 12/37 antisiphons are still implanted (survival 32%), each 3 with good, fair, insufficient and poor condition. 19 patients were converted to gravitational, four to adjustable and one to a simple DP valve. Two became shuntfree. The quote of sufficient results in long-term counts 8.1% (3/37).

Discussion: 34 years after introduction of antisiphons exist only two prospective randomized series with cumulative 430 Delta/Strata-patients (Drake 98, Kestle 05); both showed no differences compared to conventional valves in short-term. Generally we found surprisingly few studies, approx. 50% with standard and 50% with inferior results (Miyake 99), but no with superior data. 8 independent laboratory studies confirmed the excessive pressure sensivity, which plausibly explains the clinical problems.

Conclusions: In short-term antisiphons show no difference or are inferior to other valves. In the course of time the specific problems increase and lead to a poor survival- and success-quote. Adjustable valves may damp, but are unable to compensate this effect.