Effect of omental lipid fraction on enhancement of skin flap survival

Does a muscle flap accelerate wound healing of gastric wall defects compared with an omental flap?

INTRODUCTION

Most often used for reconstruction at superficial sites, a muscle flap recently was reported to promote clinical wound healing in a duodenal defect. We therefore examined whether a muscle flap could promote wound healing comparably to an omental flap in rats with gastric wall defects.

METHODS

After perforation of the centre of the anterior gastric wall, rats were divided into 2 groups. In the muscle group, a muscle flap was fixed to the defect; in the omentum group, an omental flap was placed over the defect. We histopathologically compared tissue responses during gastric wall healing.

RESULTS

While stratified villi had completely covered the defect by day 7 in both groups, scar maturation differed. Scar tissue persisted in the muscle group, but was gradually replaced by adipose tissue in the omentum group.

DISCUSSION

Both muscle and omental flaps accelerated gastric wall wound healing.

CONCLUSION

A muscle flap is an excellent alternative for repair of gastric defects when no omental flap is available.

Evaluation of bone healing in canine tibial defects filled with cortical autograft, commercial-DBM, calf fetal DBM, omentum and omentum-calf fetal DBM

The present study was conducted to compare the effects of xenogenic bovine fetal demineralized bone matrix (DBM), commercial DBM, omentum, omentum-calf fetal DBM, cortical autograft and xenogenic cartilage powder on the healing of tibial defects in a dog model to determine the best material for bone healing. Seven male adult mongrel dogs, weighing 26.2 ± 2.5 kg, were used in this study. Seven holes with a diameter of 4-mm were created and then filled with several biomaterials. Radiographs were taken postoperatively on day 1 and weeks 2, 4, 6, 8. The operated tibias were removed on the 56th postoperative day and histopathologically evaluated. On postoperative days 14, 42 and 56, the lesions of the control group were significantly inferior to those in the other group (p < 0.05). On the 28th postoperative day, the autograft group was significantly superior to the control and omentum groups (p < 0.05). Moreover, calf fetal DBM was significantly superior to the control group. There was no significant difference between the histopathological sections of all groups. Overall, the omentum and omentum-DBM groups were superior to the control group, but inferior to the autograft, commercial-DBM, calf fetal DBM and calf fetal cartilage groups.

Wrapped omentum with periosteum concurrent with adipose derived adult stem cells for bone tissue engineering in dog model

Adipose derived adult stem cells (ASCs) are multipotent cells that are able to differentiate into osteoblasts in presence of certain factors. The histological characteristics of periosteum makes it a specific tissue with a unique capacity to be engineered. Higher flexibility of the greater omentum is useful for reconstructive surgery. These criteria make it suitable for tissue engineering. The present study was designed to evaluate bone tissue engineering with periosteal free graft concurrent with ASCs and pedicle omentum in dog model. Twelve young female indigenous dogs were used in this experiment. In omental group (n = 4), end of omentum was wrapped by periosteum of the radial bone in abdomen of each dog. In omental-autogenously ASCs group (n = 4), 1 ml of ASCs was injected into the wrapped omentum with periosteum while in omental-allogenously ASCs group (n = 4), 1 ml of allogenous ASCs was injected. Lateral view radiographs were taken from the abdominal cavity postoperatively at the 2nd, 4th, 6th and 8th weeks post-surgery. Eight weeks after operation the dogs were re-anesthetized and the wrapped omenum by periosteum in all groups was found and removed for histopathological evaluation. Our results showed that omentum-periosteum, omental-periosteum-autogenous ASCs and omental-periosteum-allogenous ASCs groups demonstrated bone tissue formation in the abdominal cavity in dog model. The radiological, macroscopical and histological findings of the present study by the end of 8 weeks post-surgery indicate bone tissue engineering in all three groups in an equal level. The present study has shown that the wrapped omentum with periosteum concurrent with ASCs (autogenous or allogenous ASCs) lead to a favorable bone tissue formation. We suggested that it may be useful when pedicle graft omentum used concurrent with periosteum in the bone defect reconstruction, and this phenomenon should be studied in future.

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.

Pedicle omental flap transfer combined with vascular reconstruction after wide resection of a myxoid liposarcoma in the inguinal region

We describe a case with an inguinal myxoid liposarcoma that showed a favorable postoperative course after wide resection followed by arterial reconstruction and pedicle omental flap transfer for a wide defect including the femoral artery and vein. To our knowledge, this is the first report of the vascular reconstruction combined with pedicle omental flap transfer. In the long postoperative follow-up of 6 years, the course has been both oncologically and functionally favorable. Therefore, this reconstruction technique can be considered as a good treatment option.

Omentoplasty for gastrotomy closure after natural orifice transluminal endoscopic surgery procedures (with video)

INTRODUCTION

The utility of the greater omentum has not been assessed in transluminal access closure after natural orifice transluminal endoscopic surgery (NOTES) procedures.

OBJECTIVE

Our purpose was to evaluate the feasibility, efficacy, and safety of omentoplasty for gastrotomy closure.

METHODS AND PROCEDURES

Survival experiments in 9 female 40-kg pigs were randomly assigned to 3 groups: group A, endoscopic full-thickness resection (EFTR) for transgastric access and peritoneoscopy without closure; group B, ETFR and peritoneoscopy with omentoplasty (flap of omentum is pulled into the stomach and attached to the gastric mucosa with clips but no clips are used for gastrotomy closure itself); group C, balloon dilation for opening and peritoneoscopy followed by omentoplasty for closure. The animals were observed for 2 weeks and then underwent endoscopy and necropsy with histologic evaluation.

RESULTS

Transgastric opening and peritoneoscopy were achieved in all pigs. In groups B and C, a flap of omentum was easily placed to seal the gastrotomy and then attached to the gastric mucosa with 2 to 5 clips (median 4) in 7 to 20 minutes (median 15 minutes). In group A, peritonitis developed in all animals. In both groups B and C, all animals survived 15 days with no peritonitis and minimal adhesions outside the gastrotomy site. In addition, all achieved complete healing (transmural, n = 4; mucosal ulceration, n = 2) of the gastrotomy site. One animal in group B had an 18-mm abscess in the omental flap.

LIMITATIONS

Animal model, small sample size, lack of appropriate controls for group C.

CONCLUSIONS

Omentoplasty of the gastrotomy site is a technically feasible method to seal balloon-created transgastric access to the peritoneal cavity after NOTES procedures.

Pedicled omental flaps as an adjunct in the closure of complex spinal wounds

STUDY DESIGN

A retrospective clinical study.

OBJECTIVE

To evaluate the safety and efficacy of using an omental flap in complex spine reconstruction in patients at high-risk for wound dehiscence.

SUMMARY OF BACKGROUND DATA

Postoperative wound dehiscence represents a major cause of morbidity in patients undergoing instrumented spinal reconstruction. A variety of approaches for the prevention and treatment of this problem have been previously described in the literature; however, the use of omental flaps has received little attention.

METHODS

In this retrospective analysis, 5 patients were studied both clinically and radiographically. The study population included 4 women and 1 man, with a mean age of 49 years (range, 31-67 years). All patients underwent an omental flap procedure at the time of spinal reconstruction because of significant soft tissue defects or active spinal infection. Mean clinicoradiographic follow-up was 53 months (range, 36-115 months).

RESULTS

At the time of follow-up, all patients had well-healed surgical wounds with an acceptable structural and esthetic result. One patient in the study group experienced minor supra-fascial wound dehiscence. In terms of spinal outcome, all patients achieved successful bony arthrodesis; 1 patient, however, developed symptomatic adjacent segment degeneration and was treated by extension of the fusion construct.

CONCLUSION

In patients undergoing thoracolumbar surgery who are at high risk of spinal wound dehiscence, closure using a pedicled omental flap is a viable procedure that may limit the risk of dehiscence and improve outcome.

Use of the Internal Mammary Vessels as Recipient Vessels for an Omental Flap in Head and Neck Reconstruction

The availability of reliable recipient vessels for free flap transfer in head and neck reconstruction may be limited in cases of prior neck dissection or radiation therapy. One solution is to use the internal mammary vessels as recipients for a free omental flap. Five patients were treated with free omental flap transfer using the internal mammary vessels as recipient vessels during head and neck reconstruction. Two patients presented with a pharyngocutaneous fistula, 1 had mandibular osteomyelitis, 1 had primary esophageal cancer, and 1 had bilateral cervical radiation ulcers. All patients had received radiation therapy previously (average dose, 75.4 Gy), and 4 had undergone neck dissection (3 bilateral and 1 ipsilateral). All patients were reconstructed using a free omental flap. Four patients had a second free flap combined with the free omental flap (3 free jejunal flaps and 1 free fibular osteocutaneous flap). The mean follow-up was 26.4 months. All free flaps took entirely, the only complication ileus requiring reoperation in 1 patient. The internal mammary vessels are reliable recipient vessels for a free omental flap in head and neck reconstruction. This procedure is a good option for patients in whom previous surgery or radiation therapy has compromised local recipient vessels.

A Random-Pattern Skin-Flap Model in Streptozotocin Diabetic Rats

BACKGROUND

Flap operations are frequently performed in diabetic patients. Nevertheless, we could find no experimental study examining diabetes mellitus's effect on the flaps' survival. For this reason, we designed this study as a random-pattern skin-flap model of diabetic rats in 1999.

METHODS

We used 72 rats weighing about 200 g each. The animals were divided into 2 groups, 1 experimental (diabetic) and 1 control (nondiabetic). Following their diabetic periods, we elevated the rats' modified McFarlane flaps and measured their viable flap areas.

RESULTS

The mean percentage of the flap area surviving was 51.40% in the 2-week experimental group. It was 48.20% in the 4-week experimental group and 36.70% in the 8-week experimental group. The mean percentage of flap area surviving was 65.87% in the united control group (the total of all control groups). The mean surviving skin-flap area in the united control group was significantly higher than in the 4- and 8-week experimental groups. Moreover, the mean surviving flap area in the 8-week experimental group was significantly lower than in the 2-week and 4-week experimental groups.

CONCLUSIONS

Our study demonstrated that a 4-week diabetic duration for rats is sufficient to observe diabetes' deleterious effects on the flaps' viability. These effects were significantly established, however, after 8 weeks of diabetes. To obtain definitive results, at least 8 weeks of diabetic duration are preferred for similar studies.

Experimental induction of heterotopic bone in abdominal implants

Induction of bone tissue requires three elements: osteoprogenitor cells, osteoinductive factors, and a supporting extracellular matrix. In this study, we report on an experimental model in dogs of heterotopic bone tissue production, based on the integration of these osteo-inductive factors into abdominal implants. The implants consist of either a type I collagen sponge wrapped with periosteum and omentum or a type I collagen sponge embedded with demineralized bone powder, platelet-rich plasma, thrombin, and calcium chloride wrapped with omentum, with or without periosteum. Automated histomorphometric analysis showed an efficient production of trabecular bone, which corresponded to 50-70% of the total tissue composition 4 months after implant formation. High expression of the osteoinductive cytokines transforming growth factor-beta and bone morphogenetic proteins-2 and -4 was shown by immunohistochemistry in macrophages, endothelial cells from neoformed capillaries, osteoblasts, osteoclasts, and the mesenchymal tissue around the bone trabeculae. These approaches are novel and efficient surgical procedures to produce mature trabecular bone that could be used as a potential source of bone tissue for autotransplantation.

Omentopexy for reconstruction of the perineum following a radical vulvectomy: a case report

Colorectal surgeons have used omentum based on the left gastric epiploic vessels after any major operation in the pelvis(1). Omental flaps reach very well into the pelvis by the retrocolic route and have been used in the past for better and quicker healing of perineal defects following abdominoperineal resections(2,3). Omentum has excellent healing properties, which can be, used even as free flaps(4).

The greater omentum. Anatomy, embryology, and surgical applications

The significance of the greater omentum has been discovered recently by surgeons of various disciplines because it provides an excellent plastic material against inflammation and irradiation and for repair of defects that can be applied in the abdominal cavity; or it can be exteriorized and lengthened at a vascular pedicle and detached using microvascular anastomoses. Anatomic features, such as the volume of the omentum and the arrangement of the blood vessels, determine the lines of dissection. The eminent omental potential and the different biochemical and immunologic functions are unique, and can be related to specific anatomic structures, some of which may be drawn back to its embryologic sources. The ability of absorption and adhesion formation, neovascularization, and infection defense by the omentum protects against irradiation damage, accelerates healing of dead space, and improves the complication rate and quality of life after application to a wound bed.