What If There Is No Change in the Front View After Square Jaw Surgery?

If there is no change in the facial contour in the front view after square jaw surgery, the following causes can be considered.

 

1.     In cases where the masseter muscle covering the lower jawbone, or facial fat, is significantly developed

2.     In cases where only a small amount of the angular part of the lower jawbone was removed during square jaw surgery

3.     In cases where only the cortical bone was removed during square jaw surgery

4.     In cases where the body portion of the lower jawbone was not properly refined during square jaw surgery

 

 

1.     In cases where the masseter muscle covering the lower jawbone, or facial fat, is significantly developed

Figure - X-ray and 3D CT

As shown in the figure, a person's facial contour is supported by the facial bones, but it is also greatly affected by soft tissues such as the muscles, subcutaneous fat, and skin covering the facial bones.

When the face has little muscle or fat and the bone shape stands out, patients are often highly satisfied with the changes in appearance after square jaw surgery or cheekbone surgery that alter the shape of the facial bones. On the other hand, if the facial muscles are well developed or there is a lot of facial fat, appropriate treatment for these factors is needed in order to experience an overall change in facial contour.

Important areas in the lower facial contour related to square jaw surgery are as follows.

Lower jawbone, muscles (masseter muscle covering the lower jawbone), subcutaneous fat (fat tissue between the muscle and skin), salivary glands

Therefore, even if an appropriate amount of bone has been refined during square jaw surgery, if the change in facial shape is insufficient, it is appropriate to consider proper treatment such as reducing the amount of muscle or reducing the amount of facial fat.

 

 

2.     In cases where only a small amount of the angular part of the lower jawbone was removed during square jaw surgery

Photo - X-ray and 3D CT in cases of undercorrection

 

In many cases, a result often seen after parotid-area square jaw reduction surgery or minimally invasive square jaw surgery is that there is little difference after surgery.

In the contour of the lower jaw, the area that is important for changes in the front view is not the angular part of the lower jawbone covered by the masseter muscle, but the area in front of it that connects toward the lips.

Nevertheless, if only the angular part of the lower jaw is slightly refined through a parotid-area incision, patient satisfaction after surgery will inevitably be lower.

 

3.     In cases where only the cortical bone was removed during square jaw surgery (when only cortical bone resection was performed)

Photo - Images and measurements showing the thickness of the lower jawbone, 3D CT of cortical osteotomy

 

One of the commonly known misconceptions is the mistaken claim that cortical bone resection is the best option if front-view improvement is desired.

As shown in the photo, the thickness of the lower jawbone on one side is no more than 10 to 15 mm.

Cortical bone resection is a procedure that removes only the outer cortical bone, which accounts for one-third of the entire thickness of the lower jawbone.

Therefore, it only reduces the thickness by about 3 to 4 mm at most on one side.

To experience a postoperative change in the front view, reducing the cortical bone is of course important, but a procedure that smoothly refines the entire thickness of the jawbone, including the angular area, is essential.

 

4.     In cases where the body portion of the lower jawbone was not properly refined during square jaw surgery

Photo - 3D CT showing the importance of the mandibular body in the front view, pre- and postoperative 3D CT

 

As shown in the figure, the important part of the lower jawbone in the front view is the body portion of the lower jaw that is developed in front of the masseter muscle.

If, during square jaw surgery, only the angular part of the lower jawbone covered by the masseter muscle is sharply shaved down, there will not only be little effect in the front view, but it will also create a very awkward jawline in the side view.