DIEP flap, which is a free flap, preserves the rectus abdominis muscle and anterior rectus sheath, contributing to reduced donor site morbidity compared to TRAM flap, such as abdominal hernia and bulge [2,3,4]. However, the frequency of abdominal bulges has been reported to range from 1.6 to 33% [8,9,10,11,12,13]. An abdominal bulge is defined as abdominal wall laxity without an associated fascial defect [14]. Considering the significance of cosmetic outcomes in breast reconstruction, an abdominal bulge has considerable impact on a patient’s quality of life. Some reports suggest that abdominal bulge may be reduced using a mesh [8, 9, 15], while other studies have indicated no significant effect [3, 10, 11, 16]. Currently, the effectiveness of using a mesh to address abdominal bulges remains inconclusive [5]. Although therapeutic interventions may be required in a few cases, there is currently no established treatment.

The laparoscopic intraperitoneal onlay mesh (IPOM) technique for abdominal hernia has been shown to reduce the risk of wound infection and hospital stay compared with the open technique [17]. However, IPOM causes serious intestine-related complications, such as intestinal adhesion and enterocutaneous fistulas [18]. Furthermore, pain is a problem in both the early and late postoperative periods. It has been suggested that postoperative pain is associated with double crown fixation and transfascial sutures in IPOM plus, with a reported residual chronic pain rate of 12% [19].

The eTEP technique is an adaptation of the Rives–Stoppa technique that involves laparoscopic dissection of the bilateral retrorectal space [6, 7]. Placing the mesh in the retrorectal space prevents direct contact with the intra-abdominal organs, thereby reducing the risk of intestinal complications. Additionally, it obviates the need for Tucker fixation, thereby mitigating the risk of postoperative pain [20].

Currently, there is no established treatment protocol for abdominal bulges after DIEP flap breast reconstruction. While a consensus regarding the efficacy of mesh in preventing abdominal bulging is lacking after DIEP flap breast reconstruction [5], as an abdominal bulge occurs, its use to reinforce the weakened abdominal wall during surgical treatment is considered reasonable. Haddock et al. [16] reported mesh repair for the surgical treatment of an abdominal bulge after DIEP flap breast reconstruction but with mesh placement using onlay repair. However, in abdominal incisional hernia, onlay mesh repair is not recommended because of the high recurrence and infection rates [21]. For recurrence, retrorectal or underlay mesh repair is recommended [22]. Rhemtulla et al. [3] recommended retrorectal mesh repair for abdominal hernia after DIEP flap breast reconstruction. Therefore, we selected the eTEP technique in this case according to abdominal hernia.

Harvesting DIEP flaps for breast reconstruction often involves extensive tissue removal, which may result in a bulky abdominal bulge. Given that the donor site for DIEP flap breast reconstruction is primarily in the lower abdomen, if the IPOM technique is used to reinforce the abdominal bulge, the mesh will extend to the pubic region, which is near the bladder and may cause fixation problems. The eTEP technique is advantageous in this regard as it allows for extensive dissection of the extraperitoneal space, including the bladder. A segment of the retrorectal space was dissected to access the deep inferior epigastric artery; however, most of the rectus abdominis muscle and anterior rectus sheath were not excised, facilitating the ease of dissection of the retrorectal space. Owing to the absence of the need for hernia dissection, the risk of pneumoperitoneum is low. If minor peritoneal injury occurs, it is minimal and easily repaired. Additionally, closure of the hernia defect is unnecessary. This suggests that the risk of interparietal hernia is low owing to the reduced probability of posterior layer breakdown [23]. If the extent of mesh placement is inadequate, TAR should be considered. In cases of a unilateral abdominal bulge, TAR on one side suffices, obviating the need for bilateral TAR. In addition, it is important to consider that the extent of an abdominal bulge can be easily identified as it is observed endoscopically under pneumoperitoneum. With the increasing use of DIEP flap breast reconstruction, the incidence of abdominal bulging is expected to rise. Therefore, we believe that the findings presented in this article are highly relevant and contribute significantly to this field.