How the Buttocks Rise After Liposuction for Buttock Ptosis (Sagging): The Mechanism
In consultations I often hear, "My buttocks sag, so my legs look short," and "Do sagging buttocks really rise after liposuction?" And after surgery, some patients ask, "I am glad my buttocks have risen, but I now see a fold under my buttocks that was not there before."
Today I will explain, step by step, why the buttocks rise when a person with buttock ptosis (sagging) has liposuction, and why a fold that was hidden inside the sagging buttock becomes visible in the process. Then we will confirm it with photos from an actual surgical case.
Buttock Ptosis and the Hidden Fold
Everyone has a horizontal fold line running between the buttock and the thigh. Textbooks call it the subgluteal fold (the fold under the buttock) and describe it as a place where the skin is firmly attached to the deep tissue. For this reason the fold line always stays in the same place, and it is the original border that divides the buttock from the thigh.
What Is Buttock Ptosis (Sagging)?
When fat increases in the buttock and its weight grows, gravity pulls the lower contour of the buttock (the lower buttock line) down below this fold line. This is buttock ptosis (sagging). Textbooks also explain that buttock ptosis is produced together by the weight and fat of the buttock, the firmly attached fold line, and gravity, and they grade the degree of sagging by the length and depth of this fold line.
Many People Mistake the Sagging Edge for the Fold
In a person with buttock ptosis, the drooping buttock tissue (skin and fat) covers the fold line, so the border fold between the buttock and the thigh cannot be seen. As a result, many people do not know where their original fold line is, and they think of the bottom edge of the part that has sagged below the buttock as their buttock fold. But that line is not a fold. It is the bottom edge of the sagging buttock, and the original fold lies higher up, hidden inside the sagging buttock.
The Mechanism by Which the Buttocks Rise After Liposuction
Buttock liposuction reduces the volume of the buttock, and the skin that had been stretched contracts by the amount of volume that was reduced. The bottom edge of the buttock, which had come down toward the thigh, then moves upward. The lower border that was thought to be the fold before surgery disappears, and a new border between the buttock and the thigh forms higher up. In other words, the buttock rises. The illustration below shows this change as seen from behind.
The left side is before surgery and the right side is after surgery. The dotted line running across both drawings marks the height of the original fold line between the buttock and the thigh. Before surgery, this fold line is covered by the sagging buttock and cannot be seen, and the bottom edge of the sagging buttock lies below it. After surgery, the buttock rises above the original fold line and a new fold line forms there, while the original fold line is revealed, remaining as a trace below the newly formed fold line.
Buttock Length Decreases and Thigh Length Increases
In effect, buttock length decreases and thigh length increases. The length of the bones has not changed; the border that divides the buttock from the thigh has moved upward. This is why the legs look longer when seen from behind.
| Item | Before surgery (buttock ptosis) | After surgery |
|---|---|---|
| Lower buttock line | Has come down below the original fold line | Rises above the original fold line |
| Border between buttock and thigh | The bottom edge of the sagging buttock (easily mistaken for a fold) | The newly formed fold line higher up |
| Original fold line | Covered by the sagging buttock and not visible | Revealed as a trace below the new fold line |
| Buttock length | Looks long | Decreases |
| Thigh length | Looks short | Increases |
A New Fold Line Forms, and the Original Fold Is Revealed Below It
When the buttock becomes smaller and rises after surgery, a new fold line forms between the buttock and the thigh. This fold line is one that was created after surgery. Until then it had been covered by the sagging buttock and could not be seen, but the original buttock fold is now exposed below the newly formed fold line and remains as a trace. The original fold that is revealed appears in exactly the shape that the person originally had.
When Patients Say "A Fold Appeared After Surgery"
This is why some patients say after surgery, "A fold appeared under my buttocks after the operation." However, that fold was not newly created by the surgery. It is the original fold line that had been covered by the sagging buttock. At Venus Clinic, we sometimes perform fat grafting in this area to soften the original fold line. Note, however, that the original fold line can become deeper when the buttocks are tucked forward, because a fold can form or disappear depending on the movement of the muscles.
Superficial Liposuction That Draws Out Skin Contraction
The force that raises the buttock ultimately comes from contraction of the skin. At Venus Clinic, we encourage skin contraction with superficial liposuction, in which even the shallow fat layer just beneath the skin is suctioned evenly. Liposuction textbooks also explain that suctioning the shallow layer can provide good skin contraction without forcibly removing the deep fat.
Just Below the Fold Line: Shallow and Conservative
The bulging area of the upper back of the thigh, just below the fold line, is called the banana fold in textbooks. If this area is suctioned deeply and heavily in an attempt to raise the buttock, the result can actually be unfavorable, so at Venus Clinic we refine this area carefully and only in the shallow layer.
What the Textbooks Recommend
Liposuction textbooks explain that if the area just below the fold line is over-suctioned, the remaining skin can fold over and create a second horizontal fold (a double fold) below the original fold, and that a double fold, once formed, is not easy to correct. They therefore recommend approaching this area conservatively and in a direction oblique to the fold line.
We Leave the Fat Layer at a Consistently Even Thickness
Liposuction is not an operation for removing a large amount of fat; it is an operation for leaving fat well. At Venus Clinic, we do not suction the left and right sides differently, and our principle is to leave the remaining fat layer at a consistently even thickness. When the fat layer becomes thinner, the shape of the muscles and skeleton beneath it shows through, so the result of surgery follows the shape of the skeleton and muscles that the person has.
Treating the Hips and Sacral Back Together Raises the Buttocks Further
The word "hip" is often used to mean the same thing as the buttocks, but in body contouring surgery the hips refer to both sides of the upper buttock, where the pelvis projects outward. The sacral back is the lower part of the back below the waist, just above the buttocks.
When liposuction of the hips and sacral back is performed together, the skin over the upper buttock also contracts and pulls the buttock upward, so the buttock rises further. From below, the volume of the buttock decreases and the lower buttock line rises; from above, the contracting skin pulls the buttock upward.
The outline running from below the waist to the hips, from the hips to the buttocks, and from the buttocks to the outer thighs is one continuous line. When the projection of the hips is reduced, the outline from the waist through the buttocks to the thighs is tidied up together, so at Venus Clinic we plan the hips and sacral back together when operating on the buttocks.
What to Know in Advance
Liposuction for buttock ptosis is an operation that raises the buttock by reducing the sagging; it is not an operation that removes the buttock fold. When the buttock rises, the original fold that had been hidden is revealed below the newly formed fold line, and because the position and length of that fold follow its original shape, the left and right sides may look different. How much the buttock rises varies from person to person depending on the degree of sagging and the elasticity of the skin, and if body weight increases after surgery, the weight of the buttock can increase again and sagging can recur. The fold under the buttock can also deepen depending on posture, so a habit of standing straight without tucking the buttocks forward is helpful.
Before-and-After Photos
Below are photos of a patient who had liposuction of the buttocks, hips, and sacral back at Venus Clinic. All of the after-surgery photos were taken one week after surgery. Swelling still remains at this stage, so this is not the final result, and the shape changes a little more as the swelling subsides. In each photo, the left side is before surgery and the right side is after surgery.
Rear View — Legs Together
Before surgery — rear view (legs together)
The buttocks droop downward, and the fold between the buttock and the thigh is not visible.
One week after surgery — rear view (legs together)
As the buttocks rise, the original fold becomes faintly visible.
This is a case in which the fold was hidden by buttock ptosis. Before surgery the buttocks drooped and the buttock fold could not be seen; after surgery, as the buttocks rose, the original fold became faintly visible. One more point worth noting: bruising usually remains one week after surgery, but in this patient no bruising is visible even though the photo was taken one week after surgery. The degree of bruising and swelling varies from person to person.
| Information on the Posted Liposuction Before-and-After Photos | |||
|---|---|---|---|
| - Same person | Surgery performed at Venus Clinic; same person | - Date taken | Taken around 2022; comparison at 1 week after surgery |
| - Same conditions | Edited to the same posture and size as closely as possible | - Side effects | https://en.myvenus.co.kr/should_know/38861 |
Rear View — Legs Apart
Before surgery — rear view (legs apart)
The hips, on both sides of the upper buttock, project outward.
One week after surgery — rear view (legs apart)
The hips are smaller, and the outline running from the waist to the thighs has become slimmer.
This is a case in which the outline changed as the hips became smaller. Both sides of the upper buttock are called the hips. As the hips became smaller, the outline running from the waist through the buttocks to the thighs became slimmer, and the figure changed to an hourglass shape. With the legs apart, the border between the buttock and the thigh is easier to see, and you can confirm that the lower buttock line has moved upward after surgery.
| Information on the Posted Liposuction Before-and-After Photos | |||
|---|---|---|---|
| - Same person | Surgery performed at Venus Clinic; same person | - Date taken | Taken around 2022; comparison at 1 week after surgery |
| - Same conditions | Edited to the same posture and size as closely as possible | - Side effects | https://en.myvenus.co.kr/should_know/38861 |
Side View
Before surgery — side view
The lower part of the buttock droops toward the thigh.
One week after surgery — side view
As the buttock became smaller, its lower contour moved upward.
This shows the change in the lower buttock line seen from the side. Before surgery, the lower part of the buttock drooped toward the thigh and the lower buttock line sat low. After surgery, the lower contour moved upward as the buttock became smaller, so you can see both the reduction in buttock size and the change in the lower buttock line from the side.
| Information on the Posted Liposuction Before-and-After Photos | |||
|---|---|---|---|
| - Same person | Surgery performed at Venus Clinic; same person | - Date taken | Taken around 2022; comparison at 1 week after surgery |
| - Same conditions | Edited to the same posture and size as closely as possible | - Side effects | https://en.myvenus.co.kr/should_know/38861 |
In Closing
When a person with buttock ptosis has liposuction, the volume of the buttock decreases and the skin contracts, the border between the buttock and the thigh moves upward, and the buttock rises. Buttock length decreases and thigh length increases; a new fold line forms higher up, and the original fold that had been hidden inside the sagging buttock is revealed as a trace below it. At Venus Clinic, we refine the area just below the fold line in the shallow layer, and we plan the hips and sacral back together with the buttocks so as to draw out contraction of the skin over the upper buttock as well.
Dr. Hakjun Kim, Director, Venus Clinic
