Tummy Extended After 4 Weeks Post-op, What Could Be Causing This?

It is not unusual for some patients to have some daily distension of the abdomen or bloating for a month or two after surgery.  As the pain goes away, you become more active, and the increased activity can lead to more edema build up in the tissues, leading to that distended appearance later in the day.  I would be suprised if there was something wrong with your repair internaly, but without examining you, it would be hard to know.  One of the great myths out there is that you can tighten someone so much internally that they will always be tight, no matter what.  That is simply not the case.  You can only tighten so much anatomically.  After that, if you have weakness of the abdominal wall, you will still have some laxity afterwards.  You may need to work on your core muscles when you are cleared to return to working out.  I hope this helps.

You should continue close follow up with your plastic surgeon.  Sometimes there is fluid buildup (seroma) that may cause this problem.  Otherwise, i have seen swelling in the subcutaneous tissue which will cause this effect between 4-8 weeks post op tummy tuck surgery.  As you described, it gets worse later in the day or after activity.  Generally, if this subcutaneous tissue swelling is the cause, it resolves by 2 months post operatively.

You probably have some persistent laxity of your muscle wall.  You are correct.  This is not usually because of fat -  there is typically little subcutaneous fat after a tummy tuck.  The fact that it swells during the day suggests that it is due to gas in your intestines pushing forward. 

Bottom line, you may benefit from a secondary procedure to further tighten the abdominal wall (unless you have gained weight since surgery, but this is unlikely).  I had a patient several years ago in a similar situation.  I reoperated to further tighten the wall.  It does not mean your surgeon did anything wrong.  There is a lot of pressure on this repair and it may become stretched out.  Be sure you are not constipated after your secondary muscle repair so as to avoid any excessive pressure on the repair.  Your surgeon may offer you a price break for this touchup procedure.  But it is a decision to reach only after visiting your surgeon and discussing it with him or her.