Lateral Slits

When you are discussing the most modern and effective techniques of hair transplantation one must include a discussion of lateral slits. This innovation was created and introduced by Dr. Jerry Wong and Dr. Victor Hasson of Vancouver Canada and was ignored for years until the introduction of custom cut blades (see dense packing) and procedures exceeding 2,000 grafts in one session (see megasessions).

Before grafts were placed “laterally” (slits made with head and tail in the direction of ear to ear) they were placed “vertically” (slits made with head to tail in the direction of front to back). Placing grafts vertically served the hair transplant industry very well for years. In fact it had benefits that lateral slits just didn’t offer. However, with the advent of smaller blades, smaller more well refined grafts, and denser packing, the advantage flipped from the vertical slit to the lateral slit. Here’s why:

Until follicular unit grafting, all grafts were cut rather chunky into obsolete mini and micrografts. That is, a lot of extra tissue was kept around it because it was easier to produce a graft this way and it provided extra protection for the graft when being handled. But when grafts started to be divided down to much smaller follicular units it became obvious that the natural anatomy of the follicular unit was flat and that the hairs tend to grow out of the graft in a straight line with one follicle laying next to each other like picketing on a fence.

So like shingles on a house, the best way to maximize the coverage of the scalp was by orienting these grafts so that they lay flat on the scalp. The opposite analogy is that when they are placed in the vertical orientation it would be like stacking the shingles of a house edgewise on their side. If this were to be done one would need 20 times as many shingles to cover the house.

Another analogy is to take a book and put it on the table in such a way as to cover as much of the table as possible. You could balance the book on it’s edge and cover maybe a few inches (vertical orientation) or, you could lay it flat on the table(lateral orientation) and cover a far greater area.


Another benefit of lateral slitting is most appreciated when performing dense pack procedures. Rather than the pressure of displacement of each newly placed graft extending out laterally toward it’s neighbors causing “pop out” of previously placed grafts, lateral slitting redirects the pressure of displacement by ninety degrees into the area above and below the graft thereby minimizing lateral pressure and “popping”. The bottom line is that you can pack more densely than with vertical slits.