What is best practice to treat abdominal bulge and hernia after DIEP flap?

Hello!  Thank you for your question!  A true hernia after such procedures is very uncommon. Abdominal bulge is more common to occur, if they do at all.  More commonly on the TRAM side. Regardless, you will need to discuss this with your surgeon.  An examination will be necessary.  A surgical procedure may be necessary, via simple repair/plication, component separation, or placement of a mesh, in order to correct. A determination on if these will even need to be repaired, and if so, how, will be made by your surgeon. Best wishes!

At this point, you will require a hernia repair with mesh. It is typically recommended to wait at least 3 months or 12 weeks to pursue any further surgery. Your plastic surgeon may or may not choose to have a general surgeon assist him or her with surgery if a true hernia is present. While mesh has its own set of risks, it is often necessary to reinforce weak or absent fascia following a hernia repair.

Bulge/hernia reconstruction after DIEP is best managed with either an open Reeve-Stoppa type retro rectus sublay mesh or a laparoscopic mesh depending on the size and location of the bulge/hernia. I have found the Reeve-Stoppa repair to be extremely strong and durable. I use the existing DIEP abdominal scar as my incision.

Bulges after DIEP flap harvest are a possibility (as well as free TRAM) - and this can be weakness in the abdominal wall, a true hernia, or possibly fluid. 
Revisit with your surgeon for evaluation and likely further tests would be needed ie. CAT scan. 
In the mean time - if no pain when it bulges or any other symptoms other than cosmetic - you can wear an abdominal binder for some support - likely this can be fixed after the precise diagnosis is made. 
Best of luck.

I'm sorry to hear that you are having trouble after your reconstruction. Bulges and hernias are more common with TRAM flaps, but can occur with DIEP flaps as well. You are probably aware that during a TRAM flap, the rectus muscle is taken along with the skin and fat for the reconstruction and weakens the abdominal wall. DIEP flaps preserve the rectus muscle, but if the nerve supply to the muscle is interrupted the muscle looses its tone and will result in a bulge. Simply reinforcing the abdomen with mesh will repair the hernia, but will not completely restore the muscle tone in the abdominal wall. The repair will require recruitment of your oblique muscles to restore abdominal tone and is successful in correcting the issue. I have treated many patients with both TRAM and DIEP flap bulges and would be happy to walk you through the procedure, explain the anatomy further and why it's successful. I hope this helps.

Following a DIEP flap, there may an abdominal bulge secondary to weakness of the abdominal wall where the flap was harvested.  Hernias are less common, but can occur.  An examination is necessary, along with a CT scan, potentially.  Please discuss with your surgeon.  If needed, a mesh can be placed above the abdominal wall to buttress that area to repair it.  Best wishes.