An answer to a patient’s question from the ABC-zdrowie portal:
It has been 2 years since my vasectomy – is there still a risk of recanalisation?
MALE, 49, ZAMOŚĆ
FULL ANSWER
Yes. But fortunately a very small one.
Depending on the method used, recurrences happen more or less often.
So-called “recanalisation” does not mean that the two cut and somehow “blocked” ends of the “tubes” – through which sperm normally travel from the “factory” to the “warehouse” – meet again and grow back together.
The phenomenon is dynamic in nature.
A man after a vasectomy (usually, though not always) still produces healthy, functional sperm.
Highly motile and in huge numbers – hundreds of millions. Every normal sperm cell carries so-called acrosomal enzymes (proteolytic = dissolving protein structures) at the “tip” of its head.
What are these enzymes? What is their role?
These enzymes can dissolve tissue, so that the sperm can “drill/burn” a hole in the “shell” of the egg cell, the so-called zona pellucida. Once released, these enzymes can also dissolve other tissue structures. That is the first point.
Secondly, with such an enormous number of sperm, moving freely in every direction and highly motile – if somewhere in some labyrinth there is even the smallest “passage”, some will find the right way through.
Fortunately, these “destructive” actions of the sperm are met by a counter-response from the body, which “sends in” the “bricklayers” who “patch the holes” and “devour the intruders”. These are immune response processes as well as repair processes. Usually the repair forces prevail over the sperm invasion. However, in men with particularly strong semen, motile sperm may periodically appear in the ejaculate.
Depending on the method used, recurrences happen more or less often.
Among the least effective, with a sperm-return rate of up to 13%, are the old methods involving cutting the vas, tying both resulting ends with thread and leaving them in the same space.
Here it is worth explaining why.
The vas deferens is a very thick-walled “pipe” with a diameter of 2-4 mm. The lumen of this “pipe” is about 0.3-0.5 mm across. The wall of this “tube” is built of living muscle cells. These cells need a blood supply delivering oxygen and nutrients to survive. If the vas is squeezed tightly with a ligature – to block the passage of sperm through the lumen – the very fine blood vessels supplying the muscle cells of the wall are also clamped. The undernourished cells consequently atrophy. The walls of the tied ends of the vas become thinner, and the once-tied, rigid thread no longer compresses them. The lumen opens up. And if both ends of the cut vas are in the same space – it’s an easy road to the penis and the ejaculate.
Fortunately, these methods are being used less and less.
According to the American Urological Association’s report, the most effective method is the one with an open testicular end brought outside the sheath, and thermal coagulation of the prostatic segment of the vas.