[Paper Review] A Stepwise Approach to Aesthetic Chin Surgery: Correction of Chin Asymmetry, Microgenia, and Long Chin

Hello, I’m Dr. Hyunwoo Jo of 3D Plastic Surgery.

To keep up with the latest trends, I often look up research papers.

Recently, Google started a paper subscription service, so I signed up.

Instead of having to search through various journals to see whether there might be a good paper, I can simply set the keywords I want and good papers are delivered to me. It feels like the world is getting better and better these days. Today, I’d like to introduce a very fresh paper.

This paper was published in PRS, one of the most prestigious journals in plastic surgery.

It was presented in Korea, and it turns out to be a paper written by a director from the Facial Bone Contouring Surgery Research Group, which I belong to.

Let me review it.

The authors analyzed chin surgery in a total of 208 patients, based on surgeries performed from 2015 to 2020.

They recommend aesthetic chin surgery for three reasons:

• When chin asymmetry is judged to be a problem

• When the patient wants correction of horizontal or vertical imbalance

• When there are symptoms related to a previous chin surgery

It says surgery was performed in these three cases.

The treatment principles show that surgery was performed according to the algorithm in the table above.

In patients with chin asymmetry, imbalance, microgenia, or a protruding chin:

If there is bone resorption (Group 3), chin surgery including bone grafting is performed.

If there is no resorption and the left-right width is not broad (Group 1), correction of the chin is performed through horizontal osteotomy.

If the left-right width is broad (Group 2), chin surgery is performed with both horizontal and vertical osteotomies.

I think Group 2 is probably the chin surgery we usually know as T-osteotomy, and similar procedures.

This figure explains how asymmetry is corrected.

This patient’s chin is slightly shifted to the left and appears a little long.

A yellow dotted line is drawn below the midline of the upper front teeth in the maxilla,

and vertical lines are drawn based on the first molars on both sides to create points A and B.

Then the point where a slightly diagonal line meets the midline is called C.

Now, based on the mandible, a blue dotted line starts from the midline of the lower front teeth, and vertical lines are drawn.

Points A' and B' are marked at equal distances from both Menton points (chin points), and then a blue line is drawn again at a slight angle.

It seems to emphasize designing the bone in the shape of an isosceles triangle.

After that, the bone in between is removed and points C and C' are brought together, which is a surgical method that corrects the asymmetry while rotating the chin slightly to the right.

The authors say that a more beautiful side profile can be created through square jaw surgery on the lateral area.

In Group 2, to increase the contact area of the T-osteotomized bone, they widened the contact area through a trapezoidal osteotomy that becomes broader toward the back.

They say that the width and volume can be adjusted by controlling the amount of bone being osteotomized.

For Group 3 patients, when there was bone resorption due to a chin implant or when the step-off between bones was severe, autologous bone grafting was considered.

As I always feel when reading papers, even when I think I already know the information, there are always points I had never thought of, so it is truly very educational and helpful.

The surgical patient groups consisted of 176 asymmetry corrections, 136 length reductions, 85 width reductions, 43 chin advancements, and 29 chin setbacks.

Among the total of 176 asymmetry patients, 135 had left-sided asymmetry and 41 had right-sided asymmetry.

After surgery, the distance between the patients’ midline and Menton (chin point) significantly decreased from 2.6 to 0.85 and from 2.1 to 0.8.

Looking at the patients’ cases:

This is a case in which asymmetry was corrected through horizontal osteotomy in a patient whose chin was slightly rotated to the right.

As the chin length was reduced, the deviation improved significantly.

3D Plastic Surgery patient: a case in which asymmetry was corrected through horizontal osteotomy in a patient whose chin was rotated.

The second case is a T-osteotomy case in a patient whose chin was slightly wide.

After surgery, you can see that the chin became slimmer.

3D Plastic Surgery patient: a T-osteotomy case in a patient with a wide chin.

The last patient had significant bone resorption due to a chin implant.

It says that while performing the T-osteotomy, the remaining central bone was grafted to the front so that the blue area of bone could heal well.

3D Plastic Surgery patient: a case in which advancement surgery was performed after removal of a chin implant

Among most of the patients, 92.8% were found to be satisfied with the surgical results, and 7.2% were found to have no particular change.

Even when bone surgery goes well, it seems that there are patients who do not feel a visible change at about this rate.

Among 208 patients, 12 patients, or 5.8%, experienced temporary loss of sensation, but all recovered well. The cause was stretching of the nerve during surgery, but sensation recovered in all cases.

Patients often worry about numbness after chin surgery, but the paper says that if the surgery is performed accurately, this all recovers, so there is no need to worry.

What is notable here is that there were many chins deviated to the left.

According to several dental papers and cases of congenital anomalies, there are also papers stating that many patients are deviated to the left.

I have also felt this while operating on patients, and statistically it seems to be true.

In conclusion, the authors state that surgery using osteotomy for asymmetry of the chin bone can produce good results.

I agree with this as I read the paper as well.

Today, I reviewed a paper about the stepwise approach to aesthetic chin surgery.

Patients who study a lot may already know all of this.

But since it is content published in a highly credible academic journal, I reviewed it once.

Thank you.