Patient, female, 33 years old. She was admitted to the hospital for “2 years after mastectomy for chronic abscess in the right breast”. The patient underwent “right breast mastectomy” 2 years ago for “right breast abscess with sinus tract formation” and the incision healed well after surgery. Now she came to our hospital for surgery because of the impact on her appearance. Physical examination: stable vital signs, clear consciousness, no abnormalities on routine cardiopulmonary and abdominal examination, and no positive neurological findings. The left breast was fuller and the volume measured by drainage method was 350 ml, while the volume measured by drainage method was 50 ml after the right mastectomy, with the upper part of the mastectomy and the clavicle and axillary fold area. Measurements: distance from the upper sternal incision to the nipple: 21 cm on the left and 14 cm on the right; distance from the nipple to the anterior midline: 12 cm on the left and 7 cm on the right; distance from the nipple to the inferior fold: 7 cm on both the left and right. Past history: history of “appendectomy” and “cesarean section” (median incision), denied other medical history, no history of “drug and food allergy”. “No history of drug or food allergy. Pre-operative diagnosis: right breast defect after surgery. Preoperative design: The left inferior abdominal wall artery and thoracic umbilical penetration branch were measured by Doppler, and the direction and location of the right internal thoracic artery were marked. Three superficial veins were marked under the skin of the right breast and labeled, and the direction of venous return was measured by the evacuation method. The thoracic umbilicus was crossed with the midline in a 45° direction, and a 22 cm×11 cm flap was designed in the left lower abdomen with the distal end reaching the anterior axillary line. Surgical operation: the distal end of the flap was incised and lifted toward the umbilicus to the anterior sheath of the rectus abdominis muscle at the thoracic umbilical penetration branch, preserving 0.5 cm of anterior sheath tissue around the penetration branch and suturing it to the flap to avoid separation. The thoracic umbilical penetrating branch was separated from the rectus abdominis muscle and ligated to sever its intramuscular branches, and the thoracic umbilical penetrating branch was separated from the rectus abdominis muscle by a combination of cis-reverse meeting method, preserving a small amount of the perivascular muscle sleeve. The vessel tip was freed to the beginning of the inferior abdominal wall artery of the external iliac artery, and the flap was well hemorrhaged. Treatment of the recipient area: an incision was made from the original incision and extensive separation was made on the superficial surface of the pectoralis major fascia to form a recipient area capsule. The third rib cartilage was excised about 3 cm long to reveal the internal thoracic artery and its medial accompanying vein. The inferior abdominal wall artery was 2.0 mm in caliber and the accompanying vein was only one with a caliber of 3.0 mm, while the internal thoracic artery was 3.0 mm in caliber and the accompanying vein was also one with a caliber of 4.0 mm. After the flap was disconnected and fixed with several stitches, the vein and artery were anastomosed end to end, and the flap took 1.5 hours to re-establish blood flow, and the flap had good blood flow. The distal end of the flap and the lower part of the flap were removed and shaped to reconstruct the breast shape, and the shape of the breast was good. Postoperative management: “two resistance and one prevention”, bed rest, local warmth, no smoking and other routine microsurgical postoperative management. After surgery, the flap completely survived and the breast shape was satisfactory. The stitches were removed from the donor and recipient areas 2 weeks after surgery and the patient was discharged. The common methods of breast reconstruction surgery include breast implant, expander implant + later replacement breast implant, latissimus dorsi flap graft + breast implant, TRAM flap with tip or free graft, DIEP flap free graft, etc. The difference between the suprasternal incision and the bilateral nipple was 7 cm, the difference between the nipple and the anterior midline was 5 cm, and the difference between the breast skin in both directions was greater than 4 cm. The patient refused to undergo correction of the ptosis of the contralateral breast, so adequate skin soft tissue coverage could not be obtained by expanding the original skin with expander implants alone. The patient also refused the scar left by the latissimus dorsi flap excision, and the latissimus dorsi flap graft + breast implant was not suitable for this patient. The patient had a combined median abdominal cesarean section scar and a right abdominal scar after appendicitis, and only the left lower abdominal donor area could be used for TRAM flap graft or DIEP flap free graft. The patient’s preoperative volume deficit of the right breast was measured to be about 300 ml by the drainage method, and the average thickness of the subcutaneous fat was measured to be about 1.5 cm by the pinch and squeeze method. Since its first clinical report by Fan Qishen in 1987, the thoracic umbilical flap has been widely used in trauma repair because of its constant vascularity, large flap area, and the donor area can often be closed with direct sutures, but its application in breast reconstruction has not yet been reported. The thoracic umbilical penetration is the thickest penetration of the inferior abdominal wall artery, and the longest flap in the whole body can be designed according to this penetration. In this case, the flap area of 22 cm × 11 cm exceeded the supply range of the inferior abdominal wall artery penetration on which the unilateral TRAM flap or DIEP flap depended, but the thoracic umbilical penetration of the inferior abdominal wall artery ensured the complete survival of the patient’s flap. The subabdominal artery is often accompanied by 2 veins, and the internal thoracic artery is often accompanied by 1 vein at the 3rd rib level, so multiple subcutaneous veins should be routinely prepared in the recipient area preoperatively. Franklyn et al. confirmed by a large number of autopsies and clinical practice that if only one major regurgitant vein of the flap is anastomosed, even if the intraoperative venous anastomosis is patent, the incidence of venous crisis of the inferior abdominal wall artery perforating flap can be as high as 15%, of which about 10% needs to be relieved by bridging another regurgitant vein of the flap with a venous graft. About 5% require the establishment of a “second venous return system”, which means that the superficial veins of the flap must be anastomosed to ensure adequate return of the flap blood supply. Nho et al. suggested that the venous reflux crisis of inferior abdominal wall artery perforator flaps is often caused by the lack of effective communication between the superficial venous return system of the flap and the deep venous system of the flap, especially when the caliber of the superficial inferior abdominal wall vein is greater than or equal to 1.5 mm, which often suggests that the superficial venous return system of the flap is often dominant and must be anastomosed intraoperatively. This suggests that the venous return system of the flap is often not “all or nothing”, i.e., not always a single deep venous return or superficial venous return is sufficient to ensure blood flow to the flap. Therefore, in addition to preparing a subcutaneous vein in the recipient area, a subcutaneous vein should also be prepared in the donor area before surgery, especially when the superficial veins under the abdominal wall are thicker, the superficial veins in the recipient area should be routinely anastomosed to facilitate the venous return of the flap. When revealing the intrathoracic artery and its accompanying veins, care should be taken to avoid damaging the pleura and causing pneumothorax. If the mural pleura is inadvertently damaged, intraoperative puncture and aspiration can be used, and closed drainage of the pleural cavity is often not necessary. The location of the internal thoracic artery and its accompanying vein is deep, and the patient’s respiratory movement will make it difficult to anastomose the vessel, so the surgeon needs to have solid basic microsurgical skills to be competent.