What Are Sagittal Incisions?
Sagittal incisions is a reference to the orientation of a specific incision for placement of hair transplant grafts. Technically, it can refer to incisions for any type of graft, from punch plug grafts to follicular unit grafts.
"Sagittal" can have two definitions. The first definition is a generic catchall phrase that refers to the plane between the anterior scalp and the posterior scalp. This section includes:
- The occipitofrontalis muscle – a muscle responsible for contracting (scrunching) the forehead.
- Epicranial aponeurosis – a thick, fibrous structure that helps the occipitofrontalis muscle retract the forehead.
- Subcutaneous adipose tissue – a thick connective tissue that also surrounds other areas of the body such as the kidneys and the buttocks.
- Pericranium – a special type of connective tissue that surrounds the skull and gives the cranium a vascular system.
- The skull bone itself.
What are Sagittal Incisions?
The second definition refers to what are known as sagittal incisions. This is a special orientation that a physician can use to create recipient sites. Recipient sites are areas of the scalp where the donor hair (usually taken from a different portion of the scalp, but not always) needs to be implanted. Sagittal incision are typically created by making a tiny incision so that a follicular unit may be transplanted from one area of the body into the recipient site.
When a surgeon makes an incision for the recipient site, they can make it in any direction they so choose. With sagittal incisions, the surgeon chooses to make a tiny cut that runs parallel with the direction that the hair is intended to grow. As such, the recipient sites are fairly parallel to the anterior and the posterior scalp. This means that the incision is fairly parallel with Langer’s lines as well, which is beneficial for a multitude of reasons.
Sagittal Incisions and Langer’s Lines
Langer’s lines are used to signify the directional pattern of important protein fibers called collagen. Collagen is what forms connective tissue throughout the body. Sagittal incisions made in the same direction as the collagen will heal much more neatly than cuts made in the opposite direction (though not necessarily faster). A surgeon will often mark the Langer’s lines before the surgery so that they may have a visual indication of where to cut.
The Advantages of Sagittal Incisions
Sagittal incisions are the most popular type of incisions used by hair restoration clinics for many reasons. Since they are parallel to Langer’s lines, these incisions tend to:
- Cause a minimal amount of scarring.
- Cause a minimal amount of bleeding. This cuts down on the chances of developing issues such as infection and necrosis.
- Minimize transection rates, which is where the follicular unit is damaged.
- Allow the physician to obtain a better overall density, improving results.
Are Sagittal Incisions Always Recommended?
No, not always. There are certain exceptions. For example, when reconstructing the temporal point, an incision parallel to Langer’s lines may look artificial (though not always – it is ultimately up to the surgeon’s judgement). This is because hairs at this location tend to grow in a different direction than the hairs on other parts of the scalp, so the recipient sites should be oriented accordingly. Other exceptions may include the moustache for beard transplants, and also sideburn reconstruction, where the hair must lay much flatter to the plane of the local scalp and sagittal incisions are not especially well suited for such control.