The story of the spermatic duct valve

| 29. September 2015

For years the development of the spermatic duct valve has been Clemens Bimek’s sole focus. Now the Bimek SLV is finally ready. The inventor proved his faith in this new contraceptive device with a few self-experiments, in which he had successfully implanted spermatic duct valves in himself.

Now it’s time to take the next step – the Bimek SLV will be tested on volunteers in a series of clinical trials.

The story of Clemens Bimek and his revolutionary idea for contraception


Clemens Bimek was born in Rüdersdorf near Berlin and grew up with his three siblings in a loving, but relatively sheltered environment.


He attended school, took a craftsmanship apprenticeship and worked. Clemens Bimek became an inventor and self-taught man.


The invention of the spermatic duct valve. While watching a health advice program on TV, Clemens Bimek saw a segment about vasectomies, an operation he had never heard of before. He then asked himself: “Why not just insert a valve instead?” At the time he passed the patent office in Berlin-Kreuzberg everyday on his way to the construction site, where he worked. One day he decided to do some research on the topic and discovered that a few developments had already been attempted in this direction, but to him, these methods seemed overly complicated and therefore impractical.

Bimek had, from that point, begun to further develop his ideas and to work on a first prototype.


The Bimek spermatic duct valve was registered for patent approval in Germany (DE 199 09 427 C1). The patent was issued in 2000 and is still valid today.


During a 6 month sabbatical Clemens Bimek independently studied the subjects of andrology and urology, gaining extensive knowledge about the complex processes of male genitalia and contraception. He conducted interviews with specialists and scientists, met with many experts and, more often than not, was faced with scepticism and disregard. An equally difficult obstacle was finding a manufacturer for the micro-mechanical valve. For example, he only found particular components from a manufacturer in Florida/USA and he ordered the implant materials from Britain and Switzerland.


In addition to his self-employment, Clemens Bimek dedicated himself to the actual manufacturing of his invention. The materials used had been tried and tested in medical applications for decades and are currently used as implant materials every day. As a passive and purely micro-mechanical implant, the valve itself poses no danger to the human body.

He then gained the support of a leading member of the German Society of Andrology for his project. The andrologist agreed to test 10 spermatic duct valves on rats and he considered this animal testing to be absolutely necessary. Bimek, who is completely against animal experimentation, felt obliged to agree to the animal testing. In the end, however, he could breathe a sigh of relief, as the ethics commission did not approve the animal testing due to insufficient clinical grounds for developing a spermatic duct valve.


Bimek gained support for his ideas, as well as competent developers and a micro-mechanical implant manufacturer, when he met Dr. Kiessling (CEO), Mr Fechter and the rest of the team at Beutter. Bimek was able to have new valves manufactured, which were assembled in clean rooms, professionally packed and sterilised by irradiation (gamma).

In April 2006 Clemens Bimek had 10 complete prototypes of the spermatic duct valve that were ready to be implanted. The spermatic duct valve, which he developed with the help from a range of companies in the medical technology sector, has a technical safety code according to EWG/93/42 Annex X Par. 1.1 with reference to Annex I Par. 1 and Par. 3 and the MPG § 20 Par. 1 no. 6 issued by a Notified Body in Berlin. For this he created a risk management dossier according to DIN EN ISO 14971:2001 as well as a SOP (Standard Operation Procedure) for the assembly and implantation of the spermatic duct valve on the basis of a quality management system according to the EN ISO 9001:2000 and the EN ISO 13485:2003.

This means that the materials used are quality assured by law. The risks are minimal. The implant surgery is completed with a microsurgical operation; the process and surgical procedure of which is defined in great detail.


Clemens Bimek attempted to convince different urologists to perform the valve implantation on him. A few were prepared to do this, but were stopped by the ethics committee at each clinic. He finally found a microsurgical specialist, who allowed him to observe 3 vasovasostomies. The specialist stated that he was prepared to implant the valve for Bimek’s self experiment and even obtained approval from the relevant ethics committee.


The 17th of June was the first time Clemens Bimek was able to conduct his self-experiment and have 2 valves implanted. The surgery was filmed and documented in detail. Bimek realised that the surgeon did not install the valve 100 percent as planned. The valves were implanted in their opened state and so did not fully meet the planned expectations. This experience lead to further constructive development.


Bimek has the valves closed by means of an outpatient surgery. The results this time were promising – further professional spermiogramma indicated that no more sperm cells were present in the ejaculatory fluids.

Bimek completely redesigned the SLV and manufactured new models.


The implantation of the new valves had to be aborted, because the valve ends were made too large and could not be fitted to the spermatic ducts.


The final implant surgery, after the valve end dimensions were made smaller, took place in April. The first ejaculation with the new valves already showed an almost normal sperm count, even after Bimek’s 2 year period of sterility. With the new switch mechanism it was possible to control the valve from outside of the skin.


All the experience gained was incorporated into a new development. The current version of the spermatic duct valve was made available in different sizes and the surgical technique simplified, so that any trained urologist could perform the Bimek SLV implantation during a simple outpatient surgery (similar to that of a vasectomy).


Clemens Bimek began the search for investors and eventually gained Dr. Peter Schnückel, who facilitates innovators and inventors as an experienced businessman through his firm, PES Innovation AG (Switzerland), as a partner for the further development of the spermatic duct valve. An international patent application (PCT) was submitted for the Bimek spermatic duct valve in Switzerland. Scientific reports verified that the valve was globally unique.


The renowned urologist Prof. Dr. Dr. med. habil. H.W. Bauer, from Munich, came on board as a major supporter for this project. Additionally, meetings with interested clinics in Germany were held. The Bimek SLV appeals mainly to men, who already have children and are considering alternatives to having a vasectomy.

The official campaign for the Bimek SLV started in October, with 3 main objectives:

The Bimek SLV should be made well known to the general public.
Volunteers, who are willing to have valves implanted during the course of the upcoming clinical trials, need to be found.
Financing the clinical study and further product development will be achieved with a Crowdfunding campaign to find supporters and investors.

One response to “The story of the spermatic duct valve”

  1. […] by a German construction worker, the Bimek SLV is hailing itself as “The New Contraception for Men.” All it takes is […]

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