Just now trying to learn about the both, can any of you tell me about it? Or better yet show me photos of transplants using each of the techniques?

Lateral slits are supposed to give a more natural and dense result, because the pressure does not accumulate resulting in graft popping etc.
Vertical slits may often result in the hair standing - pointing to the skies.
I had all my graft placed in coronal incisions, a variant of the lateral slits.

First of all this term only applies if the device used to make the incision is in the shape of a flat head screw driver (or similar), which most doctors use. Upon insertion into the skin, it literally makes a slit about 1mm in length with virtually no width. In other words, it does not apply to the use of a needle that would make round holes.

The term 'lateral', meaning sideways, refers to the direction of the slit upon the scalp. A slit pointing from one side of the head to the other, or ear to ear, is referred to as a lateral slit.

Obviously, the slits can be made in any direction upon the head. A slit pointing front to back would be called a longitudinal slit.

Now the tricky part - as grafts are placed into the slit, they tend to 'lean' slightly one way or the other along the slit. Also multi-hair grafts will 'splay' like a bouquet of flowers along the slit. Picture a forest of pine trees. If all of the trees were prefectly vertical you would have a certain amount of depth of view into the forest. Now imaging that each tree was randomly leaning to one side or the other. Your depth of view would be hindered. This applies to hair on your scalp. The slightly leaning hairs in lateral slits causes your hair to be less 'see through' when looking at it from the front, thus giving an enhanced illusion of thickness.

This is my best understanding of slit direction. I am not a doctor and could be mistaken about some of the details. Feel free to add any corrections or additions.

A more accurate way of describing the opposing techniques would be perpendicular (lateral) vs. parallel or coronal (lateral) vs. sagittal.

The term literally describes the orientation of the incision in relation to the direction of hair growth and not necessarily an incision that lines up ear to ear.

With lateral slits, the angle and direction are precisely controlled. They do not have a tendency to lean if the technique is properly executed. The Lateral Slit technique (as originally developed by Hasson & Wong) by definition requires the blades used for the incisions to be custom cut to the size of the grafts themselves. This leaves no room for leaning of any sort as the grafts are very snug.

What Gorpy said about multi-hair grafts being "splayed" out is absolutely correct. The technique gives better coverage of the underlying scalp because of this and this is also what gives more density and better coverage.

I'll try to put together a sketch and upload it for you to see what I'm talking about.

Yes Jotronic, please put up a sketch. This is a confusing technique. Thanks for your input.

Everything Jotronic is right on. Here is a page on the Learning Center that describes the lateral slit technique in some detail with accompanying photos (some of yours truly! ).

-Robert

There has been a fair amount of debate among top hair transplant surgeons about the relative advantages and disadvantages of incisions made perpendicular to the direction of the hair's growth (also referred to as "lateral" or "coronal" grafting) versus incisions made parallel to the direction of the hair's growth (also referred to as "sagittal").

I have seen many surgeries in various top notch clinics using both parallel and or perpendicular incisions, with both incisions producing highly refined and minimally invasive outcomes. Physicians can carefully control both the angle and direction of the transplanted follicles using either parallel or perpendicular incisions. I have seen surgeons such as Dr. Charles, Dr. Nusbuam, Dr. Hasson, Dr. Bernstein, Dr. Konior and others perform surgeries in which all the incisions were made perpendicular with excellent results. Yet I have also seen top surgeons like Dr. Jeff Epstein, Dr. True, Dr. Shapiro and others perform excellent and highly refined dense packed surgeries using parallel incisions.

Much of the advantages typically associated with the "lateral" technique such as dense packing and minimally invasive incisions are not due to the orientation of the incisions (either parallel or perpendicular) but to the tiny size of the incisions that many top surgeons like Dr. Hasson and Dr. Wong are now using. Some of the surgeons who are doing ultra refined follicular unit grafting with very tiny blades or needles do make their incisions perpendicular, in at least some areas, while others still prefer to use parallel incisions.

When visiting Dr. Ron Shapiro in Minneapolis a couple of months ago he took almost an hour to explain what he felt were the relative advantage and disadvantages of "perpendicular" incisions versus " parallel " incisions and why he prefers to use parallel incisions for most of his incisions.

Traditionally incisions made in the hair transplant recipient area were made parallel to the direction of the natural hair. My understanding is that most surgeons felt that such parallel incisions between existing hairs minimized the chance of severing existing hair follicles. Many also felt that since blood vessels in the scalp ran vertically that incisions made parallel to these vessels would severe fewer blood vessels and thus create less disruption to the scalp.

To help me visualize this Dr. Shapiro asked me to imagine the blood vessels in the scalp as spaghetti hanging down from the ceiling. Then to imagine a big sheet of metal cutting across the room perpendicular to these blood vessels. In his opinion this sheet of metal representing a flat blade would cut more blood vessels. He then suggested I imagine a sheet of metal cutting into the room parallel to these hanging vessels. In his opinion such a sheet or blade would tend to cut in between the vessels and thus cut less of these vessels.

However, since the blades that Hasson and Wong and other leading surgeons now use are smaller and less wide this traditional concern is now not as important.

In my opinion, the idea that grafts with two or more hairs will tend to fan out across the scalp and thus create a greater illusion of density has some merit. Dr. Shapiro also seems to feel this way and thus typically does create perpendicular incisions for the 3 and 4 hair grafts that are placed in the mid scalp regions.

I think the most important advances in the hair transplant surgery in the past few years has been the evolution from standard follicular unit grafting to ultra refined follicular unit grafting. Ultra refined work using very tiny blades and or needles enables surgeons to dense pack very small grafts, while minimizing trauma to the scalp. In addition the careful orientation of the grafts in terms of direction and angle has also improved as surgeons have mastered follicular unit grafting. This enables patients to potentially get one pass sessions with faster healing and completely natural results.

I do think that Dr. Wong and Dr. Hasson in particular have done a great deal recently to elevate the "Gold Standard" from standard follicular unit grafting to ultra refined follicular unit grafting. The bar has moved higher and fortunately for patients every where many surgeons have risen to the challenge.

To acknowledge this new and higher standard only physicians who perform Ultra Refined Follicular Unit Hair Transplantation with excellent results are invited to join the Coalition of Independent Hair Restoration Physicians.

I'm pleased to announce that both Dr. Hasson and Dr. Wong have recently joined Coalition and their profiles and photos will soon be added to all our websites.

I look forward to the members of the Coalition leading the way in providing patients with the ulitmate in care, while challenging the entire
hair restoration profession to evolve to the hightest level possible.

Thanks for that in depth explanation Pat. I think I understand it now. Boy was I way off. I'm glad I didn't go to the doctor that wrongly explained it to me.

There is one point that you touched on that's still confusing. The proponents of lateral slit keep repeating the following:

"the lateral slit technique offers a high degree of control over the angle and direction in which the transplanted hairs will ultimately grow."

I don't really see how lateral slit would add any more control over any other angled slit. Won't the hair grow precisely in the direction of the slit, be it parallel or perpendicular or somewhere in between?