What Causes Upper Tummy Bulge After Tummy Tuck?

First, it really depends on the muscle repair technique
Second, it can be effected by muscle strengthening regimens.
For example, mini tummy tucks may only repair the muscle below the umbilicus, leaving the upper abdominal muscles to separate.
When a full muscle repair is perfomed, I generally prefer a two layer repair which I feel is more likely to maintain the correction over the long run. However, there is considerable variation among experienced surgeons in regard to technique and materials
Even if the enitre muscles are repaired, exercise regimens that produce separation of the muscles may cause the diastasis to recur. For this reason, I generally recommend that patients pursue core strengthening using a Pilates supervised technique in which the abdominal muscles aare contracted to the spine rather than bulging outwards as with crunches stressing the repair

There are several possibilities for bulges after tummy tuck. During the tummy tuck, the fascia is usually plicated (brought together) to tighten up the muscles. If this becomes loose, then a bulge can form in the location of the looseness. This can happy immediately after surgery or years later. This is very rare. If the bulge appears soon after surgery, you may have a seroma or fluid collection that can simply be drained and rarely needs surgery. In the vast majority of tummy tucks things like this do not happen. Good luck with your surgery.

If a mini tuck was performed with no tightening of the fascia, this could cause a bulge in the upper abdomen. Mini tucks can be performed with full fascial tightening (I e hybrid tummy tuck (TM). Still even if a beautifully performed full tummy tuck was performed bulges can result. Remember that the patient's fascia is aggressively tightened, not completely replaced with a young fascia that has never had the stretching of childbirth. Your doctor should be realistic with you. Not every abdomen will be flat after a tummy tuck if there is fat inside the abdomen or the fascia is especially loose.