Does Foreskin Restoration Regrow Nerve Endings?
Critics of foreskin restoration often make the argument that since the nerves of the foreskin are severed with circumcision, restoration won’t help because you can’t regenerate the nerve endings. While it is true that the original nerve endings do not regenerate, it is a false to say that there is no new nerve ending growth at all. It is obvious that there is proliferation of nerve endings by the fact that newly grown skin, and especially inner mucosa, is highly sensitive to fine touch. If there wasn’t any new nerve growth, then the newly grown skin would be numb, which it clearly is not.
First, it is important to understand the difference between nerves and nerve endings. Nerves are part of the peripheral nervous system. They consist of long cables of axons, which are individual nerve fibers, each connected to a nerve cell (neuron). Nerve endings branch off of nerves and are the receptors that detect stimulus. The type of nerve endings in the foreskin that we are primarily concerned with in restoration are a specific type of mechanoreceptor called Meissner’s corpuscles, which sense fine touch.
When nerves are severed and the neuron is damaged, or removed as in the case of circumcision, they do not regenerate. This is obvious to restorers in that we know the original structures of the foreskin do not regenerate during restoration. We do know however that nerves lengthen during tissue expansion.(1) Skin is an organ made up of several different types of tissue. When skin expands, it is not just the skin cells that are dividing. New blood vessels need to be grown as well to supply oxygen to the new tissue, collagen and other structural proteins to hold the new skin cells together, and fortunately for us, new nerve endings also have to be grown for the new skin to have proper sensory input.(2) In summary, what happens is that the remaining nerves lengthen during expansion, and new nerve endings will branch off of the lengthening nerves. The question then is, to what degree can new nerve endings be grown?
From what we know about skin expansion in general, the amount of nerve endings, as well as blood vessels and connective tissue in the newly grown skin, will be at roughly the same density as the original surface the skin was expanded from.(2) This is because we aren’t exactly growing “new” skin, but actually just making the existing portion of skin larger. So, theoretically, if you have 1 square cm of skin with 10 nerve endings, and you expand it to 2 square cm of nerve endings, you will now have a total of 20 nerve endings. This means that if you start with a length of inner skin between the glans and scar line of 2 cm, and you are able to expand it to 6 cm, the end result would be 3 times as many nerve endings as when you started. While this is not a regeneration of the foreskin, having three times as many highly sensitive Meissner’s corpuscles is going to make a very significant improvement in overall sensitivity.
Intactivists tend to overexaggerate how many nerve endings are in the foreskin. The number most often cited is 20,000 nerve endings, with some throwing around absurd numbers like 70,000 or 100,000. These numbers stem from a misinterpretation of older research that was extrapolated based off of nerve endings in the fingertips. The most accurate estimate from Dr. Ken McGrath is that there are around 1,500 nerve endings in the foreskin.(3) It is true however that the majority of these are concentrated in the ridged band which is completely removed during circumcision, and the frenulum which is usually entirely or partially removed. Because of this, the remaining skin we are expanding has a lower density of nerve endings than the skin that was removed. So, even if we expand the remaining the remaining skin all the way to the same surface area of a natural foreskin, it won’t have the same number of nerve endings.
This however should not discourage anyone as most of the benefits of restoring do not come from increasing the number of nerve endings. The increased sensitivity that is gained from restoring most likely is attributed to, A: recovering and dekeratinizing the glans, making the free nerve endings and pressure sensing bulboid corpuscles more sensitive, and B: restoring the gliding motion so that the bulboid corpuscles in the glans can be properly stimulated. These benefits alone are why men who were circumcised as adults and later restored typically report regaining 70-90% of sensation. When the Inner mucosa, with its high concentration of Meissner’s corpuscles, becomes internal again after restoration, it too becomes more sensitive like the glans. I suspect that there is also a synergistic effect of the gliding motion over the glans with the stretching and fine touch sensation of the inner mucosa, that together is greater than the sum of its parts. This may be why restoration can create up to a 90% regaining of sensation, even with significantly less nerve endings. The point here is that the amount of sensation that is regained is not linearly correlated to the amount of nerve endings, and that the amount of nerve endings that can be regrown does not appear to be the most important factor in restoration results.
That being said, expanding the inner mucosa as much as possible should be a priority for restorers, as it is really the only way to increase the number of Meissner’s corpuscles in a restored foreskin. An intact foreskin typically has enough inner mucosa to where it can be pulled back down the entire length of the shaft while erect. Expanding the remaining inner mucosa to this degree though could take a decade or longer, and is not necessary for a satisfactory outcome. So, when restorers ask how much inner mucosa they should grow, my answer is as much as you can, since it would be extremely difficult to grow too much.
Specific techniques that target expansion of the inner mucosa should be used as much as possible. The two most common methods are bi-directional devices, and air inflation devices. My favorite method is what I call true dual tension, which is outlined in detail in chapter 5 of The Complete Guide to Foreskin Restoration. True dual tension is essentially just using a bi-directional device with an elastic strap at the same time. The main benefit is that it allows you to tension both the outer and inner parts of the skin tube at the same time. With this method, you can expand almost the full length of the skin all at once, leading to quicker skin growth as opposed to just using a strap or bi-directional device alone. The other benefit of the true dual tension method is that it allows you to tension the inner part of the skin tube with far less pressure on the glans than using a bi-directional device alone, which is much more comfortable. The TLC-X, the DILE, and the Mantor are the only devices that allow for true dual tension as is, but others like the DTR could probably easily be modified for this method.
Conclusion
So, can you grow new nerve endings? Yes. Can you grow the same amount of nerve endings as an intact foreskin? No. Does it matter? Not as much as you would think. While expanding the inner mucosa as much as possible is important, the main focus of restoration and its benefits are from recovering the glans, and from regaining the gliding motion of the skin.
References:
1. https://www.sciencedirect.com/science/article/abs/pii/S2468451120300258
2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5111402/
3. https://en.intactiwiki.org/wiki/20,000_nerve_endings
Image: Shigeru23, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons