Laparoscopic omental flap for the treatment of major sternal wound infection after cardiac surgery

Early to midterm survival of patients with deep sternal wound infection managed with laparoscopically harvested omentum

OBJECTIVE

The optimal management of deep sternal wound infection (DWSI) remains controversial. Our objective was to evaluate outcomes of patients with DSWI managed with transposition of laparoscopically harvested omentum (LHO).

METHODS

Between 2000 and 2020, a total of 38,623 adult patients who underwent full median sternotomy for cardiac surgery were analyzed retrospectively at our institution. DSWI occurred in 455 (1.2%), of whom 364 (93.2%) were managed with pectoralis myocutaneous flap (PMF) and 33 (7.2%) with LHO. Univariate and multivariate analysis models were used to determine predictors of cumulative late mortality and adjusted survival curves were generated.

RESULTS

Among patients who received LHO, average age was 65.7 ± 9.7 years and a larger proportion of patients were male. A majority of patients (88%) had coronary bypass surgery, with bilateral internal mammary arteries use in only 21.2%. Mean length of stay (LOS) was 58.90 days and early hospital mortality occurred in 4 patients (12.1%). Patients who received LHO compared to only PMF had larger body mass index and had more heart failure. Furthermore, the hospital LOS was also significantly prolonged in the LHO group (58.9 vs. 27.4 days, p = .002), with a slightly higher in-hospital mortality (12.1% vs. 3.3%, p = .03). Late survival for LHO patients at 5 and 10 years was 71.9% and 44.8%, respectively.

CONCLUSION

Use of LHO is a safe and viable alternative to traditional myocutaneous flaps to manage complex DSWI. Early and late survival were favorable in this high-risk population.

Minimally invasive carinal reconstruction using bronchial flap and omental flap reinforcement

Carinal reconstruction and omental flap harvesting are traditionally performed via open approaches. We reported a case in which carinal reconstruction with bronchial flap and omental flap reinforcement was performed using minimally invasive approaches. The omental flap was harvested laparoscopically, and wrapped around the anastomosis, which reduced the risk of airway anastomosis complications. Non-circumferential resection and reconstruction used bronchial flap, which made it easier to perform under video-assisted thoracoscopic surgery conditions. Minimally invasive carinal reconstruction with bronchial flap and omental reinforcement after neoadjuvant treatment, can be safely performed.

Cardioplastic Approach to Omental Flap Coverage for Severe Aortic Root Infections in the Opioid Era

Aortic root abscesses are severe sequelae of endocarditis that clinically manifest as life-threatening infection. As the opioid epidemic continues to yield a national crisis, the incidence and severity of this disease process have increased. Reconstruction of the aortic root is a challenging undertaking and carries the risk of recurrent infection. The omentum has an established reputation as a reliable flap in thoracic reconstruction, given its amorphous form and immunogenic properties, but it has not been utilized for aortic root infections. We present a novel indication for the omental flap using a cardioplastic approach in coverage of aortic root reconstruction. Four patients were treated with pedicled omental flap coverage after aortic root reconstruction. All patients had successful flap healing with no evidence of recurrent infection. This series demonstrates the technical feasibility and clinical utility for providing soft tissue coverage and antimicrobial protection when used in aortic root reconstruction.

Laparoscopic omental flap for the treatment of thoracic aortic graft infection: report of two cases and review of the literature

BACKGROUND

Thoracic aortic graft infection (TAGI) is a rare and serious complication after surgery for which the treatment is controversial and challenging. Rather than following the traditional surgical strategy of graft replacement and extensive debridement, we have chosen to preserve the graft and cover it by a laparoscopic omental flap. In this article, we describe the clinical manifestation, diagnostic modalities, and treatment of this disease and analyze the role of laparoscopic omental flaps in its treatment.

CASE PRESENTATION

We present two cases of thoracic aortic graft infections that had undergone surgical graft replacement for acute Stanford type A dissection. Their clinical manifestation of infection was atypical, with computed tomography suggesting infection of the grafts. Both patients were successfully treated with debridement, laparoscopic omental transposition, and antibiotics. The first case, a 55-year-old male, was found to have an infection at the aortic arch. The second case is a 52-year-old male who was found to have infection at the ascending aorta and arch. Surprisingly, both intraoperative cultures were negative. The infections were brought under control and the patients recovered steadily after surgery. Early follow-up results showed no signs of graft infection.

CONCLUSION

These findings suggest that graft replacement for the treatment of TAGI is not always necessary in selected patients. Conservative surgical treatment, including laparoscopic omental transposition, is effective and less invasive for treating TAGI.

Effective Combination of Different Surgical Strategies for Deep Sternal Wound Infection and Mediastinitis

Purpose: Timing and ideal reconstructive approach in deep sternal wound infection (DSWI) and mediastinitis still remain controversially debated. We present our own combined surgical strategy of bilateral pectoralis major muscle flap (BPMMF) or omental flap (OF) transposition.

Methods: Between July 2010 and July 2016, poststernotomy patients with DSWI and mediastinitis underwent a secondary wound closure with modified BPMMF (Group A, center for disease control class (CDC)-II, n = 21; Group B, CDC-III, n = 20) or with OF (Group C, CDC-III, n = 19) following vacuum-assisted closure (VAC).

Results: Significant risk factors for mediastinitis (CDC-III) were chronic obstructive pulmonary disease (COPD; p = 0.001), peripheral arterial disease (PAD; p = 0.012), cardiopulmonary bypass (CPB) time (p = 0.027), total operation time (p = 0.039), total intensive care unit (ICU) stay (p = 0.011), and blood transfusion (p = 0.049). Mean antibiotic therapy (18.4 ± 8.8[B] vs. 36.2 ± 24.4[C] days, p = 0.026) and length of hospitalization (25.2 ± 12.1[B] vs 53.8 ± 18.5 days[C], p = 0.053) were significantly longer in group C. In-hospital death was 3/19 (15.8%) in group C versus 0 in group B (p = 0.026). Frequency of recurrent mediastinitis was equal (p = 0.92); however, complications occurred more often in group C (31.6% vs. 0%, p = 0.031). The mean follow-up time was 111 ± 62 days.

Conclusion: In younger (<70 years) patients without sternal bone necrosis, the BPMMF is superior to the OF technique with relatively low recurrence and mortality risks.

Chest wall resection and reconstruction for tumors: analysis of oncological and functional outcome

Background

Tumors of the chest wall have a large spectrum of well-assessed indications for resection. However, whether a reconstruction is required or not is not always clear. Complications after chest wall resection and reconstruction (CWRR) are described in literature and potentially severe. There is no evidence of how non-reconstructive management may influence the post-operative complication rate.

Methods

A total of 71 patients underwent thoracic demolition for tumors between April 2000 and October 2016. The patients were divided into two groups based on pathological findings: group 1: primary chest wall tumors; group 2: non-small cell lung cancer (NSCLC) invading the thoracic wall. They were then retrospectively analyzed by means of following criteria: TNM staging, histology, infiltration depth, 5-year survival, overall survival (OS), disease-free survival (DFS), relapse rate, R-0 resection, number of resected ribs, site of surgical resection and post-operative respiratory complications, flail chest, chronic pain, deformity of the chest wall and cosmetic results.

Results

Five-year survival, OS, DFS and risk of relapse showed a significant correlation with the presence of free surgical margins in both groups. In group 2, another parameter which correlated to survival, risk of relapse and DFS was lymph-nodal status. Moreover, the risk of post-operative respiratory complications was directly correlated with non-reconstruction after demolition of the chest wall in certain topographical sites.

Conclusions

free surgical margins are the main oncological prognostic factor in these patients. In patients who underwent resection of two or more ribs in a critical area, reconstruction of the bony thorax can significantly reduce the post-operative respiratory complication rate.

Multidisciplinary approach to chest wall resection and reconstruction for chest wall tumors, a single center experience

Background

Chest wall resection and reconstruction (CWRR) is quite challenging in surgery, due to evolution in techniques. Neoplasms of the chest wall, primary or secondary, have been considered inoperable for a long time. Thanks to evolving surgical techniques, reconstruction after extensive chest wall resection is possible with good functional and aesthetic results.

Methods

In our single-center experience, seven cases of extensive CWRR for tumors were performed with a multidisciplinary approach by both thoracic and plastic surgeons. Patients have been retrospective analyzed.

Results

Acceptable clinical and aesthetical results have been recorded, with a smooth post-operative course and a low rate of post-surgical complications. Two early complications and one late complication (asymptomatic bone allograft fracture on the site of the bar implant) were recorded. Neither postoperative deaths nor local recurrences were registered after a median follow-up period of 13 months.

Conclusions

Surgical planning is most effective when it is tailored to the patient. Specifically, in the treatment of selected chest wall tumors, the multidisciplinary approach is considered mandatory when an extensive demolition is required. Indeed, here, the radical wide en-bloc resection can lead to good results provided that the extent of resection is not influenced by any anticipated problem in reconstruction.

[Laparoscopic-assisted harvesting of omental flap in chest wall reconstruction for deep sternal wound infection]

AIM

To present an experience of laparoscopic-assisted harvesting of omental flap in chest wall reconstruction for deep sternal wound infection.

MATERIAL AND METHODS

It was made a prospective analysis of 14 patients aged 39-85 years after laparoscopic-assisted harvesting of omental flap in chest wall reconstruction for the period December 2014 - November 2016. Men/women ratio was 10/4. All patients had deep sternal wound infection grade IV (Oakley-Wright classification).

RESULTS

Postoperative complications were observed in 2 (14.3%) of 14 (95% CI: 4.0-39.9%) cases that did not require re-operation. There were no 30-day postoperative mortality and significant complications as acute intestinal obstruction, postoperative ventral herniation and transplant rejection. Mean postoperative hospital-stay was 10.5 (9; 13) days.

CONCLUSION

Laparoscopic-assisted harvesting of omental flap is safe method for chest wall reconstruction in patients with severe sternal wound infection associated with soft tissue deficiency and high risk of local complications (bleeding, etc.). Laparoscopy significantly reduces incidence of postoperative complications after omental flap transposition and is feasible in majority of patients.

Single-stage repair of the anterior chest wall following sternal destruction complicated by mediastinitis

PURPOSE

Although various techniques have been described, the ideal reconstructive procedure for treating massive sternal fragmentation and necrosis is still a matter of debate. Sometimes, reconstruction is so challenging that repetitive operations are required, particularly when complicated by mediastinitis and sternal osteomyelitis.

METHODS

Five patients (three males, two females, median age 66) with severe osteomyelitis and sternal destruction after receiving myocardial revascularization underwent partial or radical sternal resection, omental flap transposition, titanium mesh implantation and rectus abdominis muscle flap transposition. The final procedure involved single-stage closure.

RESULTS

One patient died 9 days after the final procedure due to pneumonia and septicemia. The other patients received antibiotics for at least 6 weeks postoperatively. The mean hospital stay was 36 days. Optimal wound healing was observed, with acceptable cosmetic disorders.

CONCLUSIONS

Although lateral sternal support is the first-line surgical treatment for sternal dehiscence, performing primary closure of complicated defects is often impossible. Aggressive treatment modalities are required in such cases for anterior chest wall defects. This technique provides the ability to perform rigid and stable sternal closure in complicated cases.

Mediastinitis and sternal prosthesis infection successfully treated by minimally invasive omental flap transposition

Purulent mediastinitis is a possible serious complication after mediastinal surgery. We report the case of a localized sternal plasmocytoma treated by sternectomy and prosthetic repair, who needed a second surgery for a fistulizing mediastinitis. Five months earlier, in another Hospital, the patient underwent sternal resection and reconstruction with a “sandwich” prosthesis (Methyl-methacrylate and Marlex mesh). Suppurative mediastinitis occurred and septic shock resolution was observed after the spontaneous opening of a mediastinal cutaneous fistula. After referring to our Unit the patient underwent extensive local and systemic preparation and nutritional support; the infected prosthesis was then removed and the gap filled by a laparoscopically-prepared omental flap. Adequate preoperative management, removal of any infected material and minimally invasive omental flap transposition allowed the successful treatment of this life-threatening condition.

Effects of adipose tissue stem cell concurrent with greater omentum on experimental long-bone healing in dog

Repair of large bone defects resulting from trauma, tumors, and osteitis is a current challenge to surgeons. Adipose-derived adult stem cells (ASCs) are multipotent cells that are able to differentiate into osteoblasts in the presence of certain factors. In this study, the role of greater omentum as a scaffold incorporation of ASCs was evaluated in long-bone defect healing in dog model. Sixteen 3-4-year-old, male adult mongrel dogs, weighing 25.2 ± 3.5 kg, were used in this study. In the control group (n = 4), the defect was left empty. In the omental group (n = 4), the defect was filled with harvested omentum. In the omental-ASCs group (n = 4), the defect was filled with omentum and 1 mL of ASCs was injected into the grafted omentum. In the omental-culture medium group (n = 4), 1 mL of culture medium was injected into the grafted omentum. Finally, the injured radial bones were fixed with plate and screw. Radiographs of each forelimb was taken postoperatively on the first day and at the second, fourth, sixth, and eighth weeks postinjury to evaluate bone formation, union, and remodeling of the defect. The operated radii were removed on the 56th postoperative day and were histopathologically evaluated. In this study, both omental-culture medium and omental-ASCs groups demonstrated superior osteogenic potential in healing the radial bone defect. Compared to those of the omental and control groups, more advanced bone healing criteria were present in the omental-culture medium and omental-ASCs groups at radiological and histopathological levels at 8 weeks postsurgery.

The anti-inflammatory and antibacterial basis of human omental defense: selective expression of cytokines and antimicrobial peptides

BACKGROUND

The wound healing properties of the human omentum are well known and have extensively been exploited clinically. However, the underlying mechanisms of these effects are not well understood. We hypothesize that the omentum tissue promotes wound healing via modulation of anti-inflammatory pathways, and because the omentum is rich in adipocytes, the adipocytes may modulate the anti-inflammatory response. Factors released by human omentum may affect healing, inflammation and immune defense.

METHODOLOGY

Six human omentum tissues (non obese, free from malignancy, and any other systemic disorder) were obtained during diagnostic laparoscopies having a negative outcome. Healthy oral mucosa (obtained from routine oral biopsies) was used as control. Cultured adipocytes derived from human omentum were exposed to lipopolysaccharide (LPS) (1-50 ng/mL) for 12-72 hours to identify the non-cytotoxic doses. Levels of expression (mRNA and protein) were carried out for genes associated with pro- and anti-inflammatory cytokine responses and antibacterial/antimicrobial activity using qRT-PCR, western blotting, and cell-based ELISA assays.

RESULTS

The study shows significant higher levels of expression (mRNA and protein) of several specific cytokines, and antibacterial peptides in the omentum tissues when compared to oral sub-mucosal tissues. In the validation studies, primary cultures of adipocytes, derived from human omentum were exposed to LPS (5 and 10 ng/mL) for 24 and 48 h. The altered expressions were more pronounced in cultured adipocytes cells when exposed to LPS as compared to the omentum tissue.

CONCLUSIONS/SIGNIFICANCE

Perhaps, this is the first report that provides evidence of expressional changes in pro- and anti-inflammatory cytokines and antibacterial peptides in the normal human omentum tissue as well as adipocytes cultured from this tissue. The study provides new insights on the molecular and cellular mechanisms of healing and defense by the omentum, and suggests the potential applicability of cultured adipocytes derived from the omentum for future therapeutic applications.

Deep sternal wound infection after open heart surgery: current treatment insights. A retrospective study of 36 cases

The aim of this study was to retrospectively evaluate the results of reconstructing infected post-sternotomy wounds, with either sternal plating and/or pectoralis major flap transposition or pedicled omentoplasty after previous vacuum-assisted closure (VAC) therapy. Between January 2005 and December 2010, 36 patients, suffering from deep sternal wound infection (DSWI) after coronary artery bypass grafting procedure, received (plastic) reconstructive surgery. All patients, treated in the Maastricht University Medical Centre (Departments of Plastic Surgery and Cardiothoracic Surgery), were selected for this study. For 22 patients, sternal refixation and reconstruction were obtained by sternal internal plate fixation combined with bilateral pectoralis major advancement flap. In 11 patients, a pedicled omentoplasty was performed, with or without split-skin graft and additional VAC therapy. Three patients only received a pectoralis plasty. We evaluated preoperative characteristics and post-operative course. Twenty-four patients (66.7%) had an uneventful post-operative course. Complications in the other patients included wound dehiscence, herniation of the donor site and infection of sternal plating material. Average sternal wound healing after sternal plating plus pectoralis plasty, pectoralis plasty and omentoplasty respectively accounted 7.7, 8.0 and 11.6 weeks. From our experience, we recommend VAC therapy plus delayed sternal plating and additional bilateral pectoralis major flap advancement as first repair option in case of DSWI. However, individual clinical conditions need to be taken into account when making a decision between the different available reconstructive options. Omentoplasty should be reserved for cases in which the sternum has recurrently fallen open after previous sternal plate refixation, or for cases in which the sternum defect is too extended.

Omentalisation as adjunctive treatment of an infected femoral nonunion fracture: a case report

A three-year-old male working border collie with an infected femoral nonunion fracture was managed in a two-stage procedure involving debridement and omentalisation, followed by stabilisation with a bone plate and an autogenous cancellous bone graft. Osseous union was documented radiographically 16 weeks after surgery. Telephone follow-up one year later revealed the dog had returned to full working function without evidence of lameness. To the authors' knowledge, this is the first clinical case described in the veterinary literature using omentalisation as an adjunct to the management of an infected, biologically inactive nonunion fracture.

Omental transposition: the final solution for major sternal wound infection

Sternal osteomyelitis after median sternotomy for cardiac surgery is associated with considerable morbidity and mortality. The ideal reconstruction after sternal debridement is still debated. From 2000 to 2004, we treated 15 patients for sternal osteomyelitis (type IIIB, IVA, IVB) after median sternotomy for cardiac surgery. Total or partial resection of the sternum and extensive debridement were performed in all cases. The defect was covered by omental transposition. In 11 cases, a single-stage operation took place, and a two-stage procedure was employed in 4. All patients had antibiotics postoperatively. There were 3 (20%) deaths due to cardiac failure. Hospital stay ranged from 21 to 45 days. Transient paradoxical movement of the anterior chest wall disappeared within one month. No recurrence was observed during 6 to 24 months of follow-up. Radical debridement along with omental flap transposition provides definitive control of the infection in cases of failure of other semi-conservative or surgical interventions. Prognosis depends on the general condition of the patient.

[Utility of omentoplasty for poststernotomy mediastinitis secondary to myocardial revascularization surgery]

Acute poststernotomy mediastinitis is a serious complication of cardiac surgery and is associated with high mortality. Conservative treatment with local debridement, irrigating-suction systems, and specific antibiotic therapy is sometimes inadequate. Omentoplasty is occasionally used for reconstruction and the treatment of various chest diseases. This useful procedure is most often indicated for suppurative processes and radionecrosis, to complement myoplasty, or to cover a chest wall prosthesis. When used to treat poststernotomy mediastinitis secondary to cardiac surgery, omentoplasty improves control of infection and prognosis. We describe 2 cases of poststernotomy mediastinitis secondary to cardiac revascularization surgery in which omentoplasty was an effective treatment. Excellent control of infection was achieved.

Combined Laparoscopically Harvested Omental Flap With Meshed Skin Grafts and Vacuum-Assisted Closure for Reconstruction of Complex Chest Wall Defects

BACKGROUND

Chest wall reconstruction after radiation damage is a challenge in oncologic and plastic surgery. The defect can be reconstructed with laparoscopically harvested omental flap and meshed skin grafts. Our aim was to evaluate the use of vacuum-assisted closure (V.A.C.) in combination with laparoscopically harvested omental flap and meshed skin graft for treating these complex wounds.

METHODS

Between October 2003 and December 2004, 11 patients underwent a chest wall reconstruction with laparoscopic omentoplasty and V.A.C. treatment of severe chest wall radionecrosis after breast cancer treatment (n = 10) or for locally advanced breast cancer treated first by irradiation (n = 1).

RESULTS

Laparoscopic harvesting was uneventful in 10 cases. One patient had a laparoscopic transverse colic resection because of a middle colic artery injury. Mean time of the laparoscopic procedure was 53 minutes (range: 35-120). Wound surface area averaged 360 cm (range: 80-750). The mean duration of V.A.C. treatment was 9.3 days (range: 6-16). Nine patients showed primary wound healing without adverse events. Complications occurred in 3 patients. One developed a pulmonary infection and died after healing during the postoperative course. One presented a partial flap loss, leading to delayed healing after 45 days. One patient with severe radiation damage and a complete brachial plexus paralysis required a shoulder amputation after an extensive necrosis. All but 1 patient are alive and resumed their normal daily activities.

CONCLUSIONS

Combination of laparoscopic omentoplasty and V.A.C. can successfully be used for reconstruction of complex chest wall radiation damage.

Laparoscopic Greater Omentum Harvesting with Split-Thickness Skin Grafting for Sternal Wound Dehiscence

Sternal wound dehiscence is a serious complication occasionally requiring soft tissue coverage. The greater omentum typically has been used as a last resort because of the underlying morbidity from a laparotomy. We present a case in which a laparoscopically created omental flap with subsequent split-thickness skin grafting was used to correct a large soft tissue defect that occurred after sternal wound dehiscence developed. A nonambulatory 49-year-old man who underwent coronary artery bypass grafting developed sternal wound dehiscence. Because a large soft tissue defect developed after multiple debridements, soft tissue coverage was required. A laparoscopically harvested omental flap spared this man's upper extremity musculature and provided a soft tissue bed for split-thickness skin grafting. This case helps to establish the role of laparoscopically harvested omentum. If the results suggested by this case are confirmed in a large series, omental flaps should be considered as options of first choice in the management of sternal wound dehiscence.

Omental Transposition Flap for Salvage of Ventricular Assist Devices

BACKGROUND

The use of ventricular assist devices for patients with end-stage cardiac failure awaiting heart transplantation has become increasingly common. Ventricular assist devices improve the longevity and the quality of life for these patients. In addition, they serve as a bridge to cardiac allograft transplantation until a donor heart is found. However, ventricular assist device-related infections remain a major problem complicating their long-term use. Clinical infection and sepsis can critically threaten these patients with ventricular assist devices. Infection can delay immediate transplantation and potentially require the removal of the device for definitive treatment of the problem.

METHODS

Patients who underwent insertion of a ventricular assist device at the University of Pittsburgh Medical Center were identified through accessing the medical records archives of the hospital. Review of patients' medical records was conducted to obtain patient demographics, preoperative diagnosis and disease state, type of ventricular assist device inserted, postoperative day of ventricular assist device infection onset, infectious organism identified, timing of omental flap procedure after the initial insertion, duration of ventricular assist device support before cardiac transplantation, and patient follow-up.

RESULTS

There were 76 patients who underwent a ventricular assist device insertion procedure during the 4-year period between January of 2000 and January of 2004. Of the 76 patients who received a device, 11 (14 percent) had evidence of clinical infection secondary to insertion. Two of these 11 patients died before surgical intervention, four had their devices explanted, and the remaining five underwent omental flap transposition with bilateral pectoralis major advancement flaps in surgically addressing their infections. Of the five patients with infections who received omental transposition flaps, two went on to undergo successful transplantation, two continue to await cardiac allograft transplantation, and one died as a result of an unknown cause.

CONCLUSIONS

The authors present their experience with five patients who received omental transposition flaps to cover infected ventricular assist device pumps and the associated tubing in large, open sternoabdominal wounds. Treatment included the direct application of an omental transposition flap over the infected device with use of a bilateral pectoralis advancement flap to aid in complete sternal and skin closure of the sternal wound defect. In each of these cases, the use of the omental flap was followed by resolution of the mediastinal infection. In addition, the treatment with an omental flap prevented the removal of infected devices in patients who were otherwise pump dependent during their waiting periods for transplantation. The use of omental transposition flaps can be an effective technique in salvaging infected ventricular assist devices and preserving this valuable device for patients awaiting a cardiac transplant.

Laparoscopic Harvest of an Omental Flap to Reconstruct an Infected Sternotomy Wound

Sternotomy dehiscence is associated with a high mortality rate. In most cases this complication may be treated by simple debridement and antibiotic therapy, but sometimes it is necessary to fill the sternal defect with viable tissue. The greater omentum seems to be the ideal tissue to be transposed because of its malleability, good vascularization, and high lymphatic tissue content. The transposition of the greater omentum usually requires a midline laparotomy for the preparation of the flap, with significant laparotomy-related morbidity. Laparoscopic access may represent an effective alternative for preparing and transposing the omental flap. The key points of the laparoscopic technique are (1) the coloepiploic detachment, (2) the section of the anastomotic arterial branches between the Barkow's arcade and the gastroepiploic arcade, (3) the mobilization of the greater omentum pedicled on the right gastroepiploic artery, and (4) its transposition into the mediastinum, taking care to avoid twisting the gastric greater curvature and the flap itself.