Article
Salomon Hakim. Review on patented and realized hydrocephalus valves
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Authors
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A. Aschoff
- Heidelberg
| Published: | June 4, 2012 |
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Outline
Text
Objective: Salomon Hakim, who died in 2011, wellknown as the inventor of iNPH, made major contributions in the theory of hydrocephalus and was the most innovative valve designer up to now. There are short biographical notes from Columbia and one paper to his iNPH-invention. However, a systematical reception of Hakim's work in valve engineering is missing.
Methods: Reevaluation of all papers of S. Hakim dedicated to the valve-technology and -tests, analysis of 39 US- and EU-patents, personal communications with Hakim at 4 meetings, e.g. during his visit in our valve laboratory, personal photos.
Results: The conception (1962) and patent procedures (1964–66) of his ball-valve is documented. It was not the first ball design (earlier: Nulsen/Spitz 1949, Engelsmann/Sikkens 1956), however, the Hakim-Cordis was superior to the precursors and is still one of the most common shunts. In 1973 Hakim developed the concept of percutaneously adjustable valves, which led to the Sophy- (patent Marion 84) as well to the Medos-Hakim-valve (multiple patents together with his son Carlos 84–89). Hakim's test bench published 1973 was the first, which was able to measure dynamic pressure waves. One paper (73) and 8 patents were devoted to “self-regulating” valves, which should vary their resistance dependent on ICP. Parts of this concept led to the Orbis-Sigma-, SiphonGuard- and Diamond-Valve. Hakim’s similar patents around the “Accumulator valve” were not successful. In 1975 Hakim and coworkers developed the Cordis-Lumbar-Valve, the first gravitational (g-) shunt. Unfortunately this simple and efficient solution to counteract overdrainage was designed exclusively for the lumbar shunts, and was forgotten for 2 decades. In the 90ties improved g-valves advanced to the hot spot of valve technology. Patents of pressure sensors, prechambers and reservoirs confirm Hakim's broad interests.
Conclusions: Salomon Hakim was the most innovative shunt designer, and played a decisive role in the development of ball, adjustable, gravitational and autoregulating valves.
