[Case Review] Asymmetric Creases Below the Buttocks
During consultations for buttock liposuction, we often hear patients say, "My buttocks sag, so my thighs look short," or "My backside looks flat and seems to droop downward." Yet after surgery, once the buttocks have lifted, some patients are surprised to find "a crease that wasn't there before surgery" or "creases that differ between the two sides."
Today, through the case of one patient who underwent liposuction of the buttocks, hips, and lower back, I would like to explain why the crease between the buttock and thigh that was hidden inside the sagging buttock before surgery becomes visible after surgery, and how it looks when that hidden crease turns out to be asymmetric. I will also explain the principle of correcting buttock ptosis (sagging) with liposuction.
The Hips, Lower Back, and Buttocks Form One Continuous Line
The word "hip" is often used to mean the buttocks, but in body contouring surgery, the hips refer to the prominences of the pelvis on both sides above the buttocks (the upper outer pelvic prominence). The lower back (sacral area) is the lower part of the back just below the waist and right above the buttocks.
In women, the outline that runs from below the waist to the hips, from the hips to the buttocks, and from the buttocks to the outer thighs is called a single cosmetic unit. If only one of these areas is reduced, another area can easily look relatively more prominent. For this reason, when we operate on the buttocks at Venus Clinic, we plan the hips and lower back together and refine the line from the pelvis to the buttocks as one.
What Is Buttock Ptosis (Sagging)?
Between the buttock and the thigh lies the crease under the buttock (the infragluteal fold). Buttock ptosis (sagging) is a condition in which the lower contour of the buttock (the lower buttock line) drops below this fold, so that the buttock hangs down below the crease line.
When the buttocks sag, they look longer and the thighs look correspondingly shorter, making the whole lower body appear short. Because the sagging buttock tissue covers the fold line, the crease between the buttock and thigh is hidden inside and cannot be seen before surgery.
How Liposuction Corrects Buttock Ptosis
When buttock liposuction reduces the size and weight of the buttocks, the stretched skin contracts and the lower buttock line moves up above the fold line. As a result, the buttocks become shorter and the thighs look longer. Reducing fat on the outer and lower parts of the buttocks together gathers the buttocks toward the center and gives them a lifted appearance. This is commonly called a "hip-up," but strictly speaking it is a "buttock-up," since it is the buttocks that rise.
Shallow and Careful Just Below the Buttocks
The bulging area just below the buttock, under the fold line, is called the "banana roll" in liposuction textbooks because of its banana shape. Fibrous tissue that supports the buttock from below runs through the deep fat layer of this area. Suctioning this area deeply can cut through this support structure and may instead make the buttock sag further, lengthen the fold line, or create a double crease. For this reason, textbooks and papers recommend suctioning this area only in the superficial layer and conservatively. At Venus Clinic, too, we reduce the outer buttocks and hips adequately, while carefully refining the area just below the fold line in the superficial layer.
The Whole Buttock, Hips, and Lumbar Area Together, Tailored to Body Shape
At Venus Clinic, we do not suction just one part of the buttocks; we remove an appropriate amount of fat tailored to each patient's body shape. By removing fat from the whole buttock, the hips, and the lumbar area (lower back) together, we reduce the buttocks while also inducing skin contraction, and in this way help the sagging buttocks move upward.
We Consistently Leave the Same Thickness of Fat
At Venus Clinic, except in special cases such as when the breasts are asymmetric in size, we do not perform surgery that suctions the left and right sides differently. Our principle is to consistently leave the same thickness of fat layer. As the fat layer becomes thinner, the shape of the muscles and bones beneath it shows through, so the result of liposuction ultimately follows the shape of each person's own bone structure and muscles.
After Surgery, the Hidden Crease Becomes Visible
When the buttocks lift, the infragluteal fold that had been covered by sagging buttock tissue becomes exposed. The crease is not newly formed; the crease that was already there is exposed as the buttocks rise. While the crease becomes visible, its depth usually becomes shallower.
At Venus Clinic, we place the incisions for buttock liposuction inside the infragluteal fold so that they are hard to see. However, once the buttocks lift, the incisions that were inside the fold come to lie below the fold line and become visible. The short lines seen below the buttocks in the post-operative photos are these incisions, and they are also a sign that the buttocks have actually moved upward. The color around the incisions gradually fades over time.
When the Hidden Crease Is Asymmetric
The issue arises when the crease hidden inside is asymmetric. Before surgery, the sagging buttocks cover the creases, so it is impossible to tell what they look like on each side. As a result, an asymmetric crease that neither the patient nor we knew about before surgery only becomes visible once the buttocks lift after surgery. As mentioned above, when the fat layer is left at the same thickness, the result follows the shape of the bones and muscles, so a crease that was originally asymmetric is revealed in exactly that shape. As in this case, the position and size (length) of the crease between the buttock and thigh can differ between the left and right sides.
The Buttock Crease Does Not Disappear
The infragluteal fold is a crease formed where the buttock and thigh fold, and it changes with movement and posture. So even if liposuction improves buttock ptosis, the crease itself does not fundamentally disappear. An exposed crease can be made shallower with fat grafting, but it cannot be removed, and it can deepen again in postures where the buttocks are tucked forward. Results vary by individual.
What to Know Before Surgery
If your buttocks sag, it is good to know in advance that a hidden crease may become visible as the buttocks lift after surgery, and that the crease may look different on each side. Buttock liposuction is surgery that lifts sagging buttocks so the lower body looks longer, but it is not surgery that makes the creases on both sides identical. In addition, swelling and bruising in the early post-operative period mean the shape keeps changing, and after surgery, a habit of standing upright without pushing the buttocks forward helps keep the crease from deepening.
Before-and-After Photos
Below are photos of a patient who underwent liposuction of the buttocks, hips, and lower back at Venus Clinic. All post-operative photos were taken 1 week after surgery. Swelling and bruising are still present at this stage, so these are not the final results, and the shape will change somewhat further as the swelling subsides. In each photo, the left side is before surgery and the right side is after surgery.
Surgical Case
In this case, the left buttock crease was longer and lower. Before surgery, the buttocks sagged and the creases were hidden by buttock tissue. After surgery, as the buttocks lifted, the right buttock crease became barely noticeable, while on the left the buttock lifted but the crease remained. As a result, the length and height of the buttock creases look different on the two sides after surgery.
Back view, legs together. Before surgery, the lower part of the buttocks sags toward the thighs, so the crease between the buttock and thigh is hardly visible. After surgery, the buttocks have lifted and the lower buttock line has become shorter. The crease is barely visible on the right, while it remains on the left, showing a difference in the length and height of the left and right creases. The short lines on both sides below the buttocks are the incisions that were originally inside the creases and became visible as the buttocks lifted.
Back view, legs slightly apart. With the legs apart, the boundary between the buttocks and thighs is easier to see. After surgery, a crease remains below the left buttock while the right has almost no crease, showing that the hidden creases were asymmetric. The lines of the hips (the upper pelvic prominence) and lower back were also refined. The bruising seen around the buttocks is a common part of recovery at around 1 week after surgery.
Left side view. Before surgery, the lower part of the buttocks hangs down toward the lower thigh, and the lower buttock line sits low. After surgery, the lower contour of the buttocks has moved up, the line of the back of the thigh looks longer, and the curve from the lower back to the buttocks has been refined.
Right side view. On the opposite side as well, the lower contour of the buttocks has moved up and the boundary between the buttock and thigh has risen. On the right, the crease became barely noticeable after surgery, showing that even in the same person the left and right creases can change differently.
There is one more change worth mentioning. In this patient, not only did the buttocks become smaller and the buttock ptosis improve, but as a secondary effect, the prominence of the hips seen from behind was removed. This patient had previously undergone thigh liposuction, so there were no saddlebags on the outer thighs. Before surgery, the pelvic line looked square because of the prominence of the waist and hips, but once the hip prominence was removed, the outline from the waistline at the flanks, across the outer pelvis, to the saddlebag area changed into a streamlined shape like a Coke bottle. The diagram below shows this change in outline.
On the left is the pre-operative shape, in which the waist and hips protrude and the outer pelvis looks angular and square. On the right is the streamlined shape after the hip prominence was removed, in which the outline flows as one soft curve from the waistline at the flanks, past the outer pelvis, to the outer thighs. Because the thighs already had no saddlebags, refining just the hip prominence allowed the entire outline to connect smoothly. You can also see this change in the pelvic outline before and after surgery in the back-view photos above.
| Information on the Posted Liposuction Before-and-After Photos | |||
|---|---|---|---|
| - Same person | Surgery performed at Venus Clinic; same person | - Date taken | Taken around 2026; 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 sagging buttocks are lifted with liposuction, the infragluteal fold that had been hidden becomes visible, and if that crease is asymmetric, a difference between the left and right sides may be seen after surgery. At Venus Clinic, we explain this possibility before surgery, and we operate by suctioning shallowly just below the buttocks and, tailored to body shape, removing fat from the whole buttock, the hips, and the lumbar area together, so that the buttocks are reduced while skin contraction is also induced.
For this reason, at Venus Clinic we perform fat grafting along the buttock crease line to help prevent buttock sagging and to soften the exposed crease, but the crease deepens with movements that fold the buttocks inward. Because creases form and fade with muscle movement, to keep the crease exposed after surgery from deepening, it is best to avoid postures that push the buttocks forward.
Once the buttocks lift and the sag disappears, it is only natural that the crease becomes visible; a buttock without sag and a hidden crease cannot be had at the same time. If you find that you dislike the crease that becomes exposed as the buttocks lift, we can graft fat back into the lower buttock to recreate the sag and hide the crease again.
References: Buttock Volume-Up Liposuction Volume-Up Liposuction Revision for Buttock Sagging (Ptosis) and Double Creases
Dr. Hakjun Kim, Director, Venus Clinic
