The omentum

INTRODUCTIONThe word omentum derives from the ancientEgyptians who,when embalming human bodies,used to assess their'omens'by looking at thevariations in what we recognise today as theomentum.Galen(128-199 AD)thought that therole of the omentum was to warm the intestines.This was on the basis of a gladiator who had anomental resection after a stab injury and sufferedgreatly from cold for the rest of his life.A

Reconstruction of the abdominal wall by using a combination of the human acellular dermal matrix implant and an interpositional omentum flap after extensive tumor resection in patients with abdominal wall neoplasm: A preliminary result

AIM： To present our trial using a combination of the human acellular dermal matrix （HADM） implant and an interpositional omentum flap to repair giant abdominal wall defects after extensive tumor resection. METHODS： Between February and October of 2007, three patients with giant defects of the abdominal wall after extensive tumor resection underwent reconstruction with a combination of HADN and omentum flap. Postoperative morbidities and signs of herniation were monitored. RESULTS： The abdominal wall reconstruction was successful in these three patients, there was no severe morbidity and no signs of herniation in the follow-up period. CONCLUSION： The combination of HADM and omentum flap offers a new, safe and effective alternative to traditional forms in the repair of giant abdominal wall defects. Further analysis of the long-term outcome and more cases are needed to assess the reliability of this technique.

Primary multiple extragastrointestinal stromal tumors of the omentum with different mutations of c-kit gene

The author reports a very rare case of sporadic primary multiple extragastrointestinal stromal tumors (EGISTs) of the omentum associated with different mutations of the exon 11 of the c-kit gene in a 75-year-old man with gastric cancer. During an operation for the cancer, two solid tumors (10 mm and 8 mm) were found in the omentum. Both tumors consisted of cellular spindle cells. Mitotic figures were two and three per 50 high power fields. The tumor cells were positive for KIT, CD34 and vimentin, but negative for desmin, S100 protein, α-smooth muscle actin and p53 protein. Ki67 labeling was 2% and 3%. The larger EGIST showed a deletion of codons 552-558 of exon 11 of the c-kit gene, while the smaller EGIST had a point mutation at codon 559 (GTT←GAT) in exon 11 of the c-kit gene. Exons 9, 13, and 17 of the c-kit gene, and exons 12 and 18 of the platelet derived growth factor receptor α genes showed no mutations. The case shows that sporadic multiple EGISTs can occur in the omentum.

Pedicled greater omentum flap for preventing bile leak in liver transplantation patients with poor biliary tract conditions

BACKGROUND: Bile leak remains a main complication in liver transplantation patients with poor biliary tract conditions, mainly caused by an insufficient blood supply or dysplasia of the biliary tract. Although Roux-en-Y modus operandi can be adopted, the risk of other complications of the biliary tract such as infection increases. Using pedicled greater omentum flaps to wrap the anastomotic stoma, which increases the biliary tract blood supply, may reduce the incidence of bile leak. METHODS: Fourteen patients undergoing piggy-back liver transplantation and having poor biliary tract conditions were treated with pedicled greater omentum flaps to wrap the anastomotic stoma of the biliary tract. Their clinical data were analyzed retrospectively. RESULTS: Of the 14 patients, only one (7.1%) had a mild bile leak on the 8th day post-operation and fully recovered after symptomatic treatment. The other patients had no biliary complications. CONCLUSIONS: Using pedicled greater omentum flaps to wrap the anastomotic stoma of the biliary tract is an effective way to prevent bile leak in liver transplantation patients, especially those with poor biliary tract conditions. However, experience with this surgical technique still needs to be further explored.

Multiple malignant extragastrointestinal stromal tumors of the greater omentum and results of immunohistochemistry and mutation analysis:A case report

To report an extragastrointestinal stromal tumor （EGIST） that occurs outside the gastrointestinal tract and shows unique clinicopathologic and immunohistochemical features. In our case, we experienced multiple soft tissue tumors that originate primarily in the greater omentum, and in immunohistochemical analysis, the tumors showed features that correspond to malignant EGIST. Two large omental masses measured 15 cm×10 cm and 5 cm×4 cm sized and several small ovoid fragments were attached to small intestine, mesentery and peritoneum. On histologic findings, the masses were separated from small bowel serosa and had high mitotic count （115/50 HPFs）. In the results of immunohistochemical stains, the tumor showed CDl17 （c-kit） positive reactivity and high Ki-67 labeling index. On mutation analysis, the c-kit gene mutation was found in the juxtamembrane domain （exon 11）and it was heterozygote. Platelet-derived growth factor receptor （PDGFR） gene mutation was also found in the juxtamemembrane （exon 12） and it was polymorphism. From above findings, we proposed that there may be several mutational pathways to malignant EGIST, so further investigations could be needed to approach this unfavorable disease entity.

Giant solitary fibrous tumor arising from greater omentum

Extrathoracic solitary fibrous tumors(SFTs) have been described at almost every anatomic location of human body,but reports of SFT in the abdominal cavity are rare.We herein present a rare case of SFT originating from greater omentum.Computed tomography revealed a 15.8 cm × 21.0 cm solid mass located at superior aspect of stomach.Open laparotomy confirmed its mesenchymal origin.Microscopically,its tissue was composed of non-organized and spindle-shaped cells exhibiting atypical nuclei,which were divided up by branching vessel and collagen bundles.Immunohistochemical staining showed that this tumor was negative for CD117,CD99,CD68,cytokeratin,calretinin,desmin,epithelial membrane antigen,F8 and S-100,but positive for CD34,bcl-2,α-smooth muscle actin and vimentin.The patient presented no evidence of recurrence during follow-up.SFT arising from abdominal cavity can be diagnosed by histological findings and immunohistochemical markers,especially for CD34 and bcl-2 positive cases.

Malignant mesothelioma of the greater omentum mimicking omental infarction:A case report

Mesothelioma develops most commonly in the pleura, and less frequently in the peritoneum. Usually, it manifests as diffuse peritoneal thickening and multiple nodules, and rarely as a solitary mass. We report a rare case of primary malignant mesothelioma of the greater omentum, which mimicked omental infarct. A 54-year-old Korean man was admitted because of severe abdominal pain of sudden onset. A tender mass with indistinct margins was palpated in the upper abdomen. Abdominal ultrasound and computed tomography showed an ill- def ined mass in the greater omentum and little ascites in the peri-hepatic space, and neutrophil-dominant exudates were documented on paracentesis. Intravenous antibiotics and analgesics were given for omental infarction with superimposed infection, which resulted in symptomatic improvement. The imaging studies after a week revealed a growing mass and ascites. Laparoscopic surgery was performed and an 8 cm×3.3 cm greater omental mass was found, with multiple small nodules on the peritoneum, diaphragm, and pelvic cavity wall. Histological examination showed proliferating malignant epithelioid cells that stained strongly for calretinin, which was compatible with malignant mesothelioma. We recommend that primary omental mesothelioma should be included in the differential diagnosis of patients with omental infarction, despite its rarity.

Combined transplantation of bone marrow mesenchymal stem cells and pedicled greater omentum promotes locomotor function and regeneration of axons after spinal cord injury in rats

BACKGROUND： According to previous studies, the neuroprotective effect of the pedicled greater omentum may be attributed to the secretion of neurotrophic factors and stimulation of angiogenesis. The neurotrophic factors released from the pedicled greater omentum, such as brain-derived neurotrophic factor and neurotrophin 3/4/5 could exert a neuroprotective effect on the damaged host neural and glial cells, and also could induce the transdifferentiation of transplanted bone marrow mesenchymal stem cells （BMSCs） into neural cells. OBJECTIVE： Based on the functions of the omentum of neuro-protection and vascularization, we hypothesize that the transplantation of BMSCs and pedicled greater omentum into injured rat spinal cord might improve the survival rate and neural differentiation of transplanted BMSCs and consequently gain a better functional outcome. DESIGN, TIME AND SETFING： A randomized, controlled animal experiment. The experiments were carried out at the Department of Anatomy, the Secondary Military Medical University of Chinese PLA between June 2005 and June 2007. MATERIALS： Fifteen male inbred Wistar rats, weighing （200±20） g, provided by the Experimental Animal Center of the Secondary Military Medical University of Chinese PLA were used and met the animal ethical standards. Mouse anti-BrdU and mouse anti-NF200 monoclonal antibody were purchased from Boster, China. METHODS： Cell culture： We used inbred Sprague-Dawley rats to harvest bone marrow for culture of BMSCs and transplantation to avoid possible immune rejection. BMSCs were cultured via total bone marrow adherence. Experimental grouping and intervention： The rats were randomly divided into a control group, cell group and combined group, five rats per group. Rats in the control group underwent spinal cord injury （SCI） only, during which an artery clamp with pressure force of 30 g was employed to compress the spinal cord at the Tl0 level for 30 seconds to produce the SCI model. 5 μ L PBS containing 10^5 BMSCs was injected into the injured site of the spinal cord in 60 seconds via a microsyringe in the cell group after SCI. In the combined group, after SCI and BMSC transplantation, an autograft pedicled greater omentum was transplanted onto the injured site of the spinal cord and fixed with a suture. SCI model and transplantation： Control group, SCI model without treatment; cell group, transplantation of BMSCs after SCI; combined group, combined transplantation of BMSCs and pedicled greater omentum after SCI. MAIN OUTCOME MEASURES： At days 1, 7, 14, 21 and 28 PO （post operation）, the Basso, Beattie and Bresnahan （BBB） scale was used to observe and evaluate the recovery of locomotor function. At day 29 PO, after transcardial perfusion using 4% paraformaldehyde, a spinal cord segment of 1 cm around the injury was harvested. A cryostat section was performed longitudinally in the horizontal plane and sections were chosen by systematic random sampling for staining. Anti-BrdU staining and counting was performed to measure survival rate of transplanted BMSCs; anti-BrdU-nestin and BrdU-glial fibrillary acidic protein （GFAP） double staining and counting measured neural differentiation of BMSCs; and anti-NF 200 staining was used to evaluate axonal regeneration. RESULTS： All 15 rats were included in the outcome analysis, without any loss. Changes in BBB scores： Combined transplantation of BMSCs and the pedicled greater omentum produced significantly higher BBB scores at 7-28 days post-injury than in the control group （P 〈 0.05）. BBB scores in the cell group were higher than in the control group at 28 days post-injury （P 〈 0.05）. Survival rate and neural differentiation of transplanted BMSCs： Immunostaining of BrdU demonstrated that transplanted BMSCs survived in the spinal cord and migrated cranially and caudally as far as 0.5 mm from the injection site in the cell group and combined group. Some of the transplanted BMSCs expressed nestin or GFAP which revealed neural differentiation of BMSCs in the combined group and cell group. Axonal regeneration： The areas of axonal NF200 staining in the cell group and control group were lower than that of the combined group （P 〈 0.01 ）. CONCLUSION： It is effective and feasible to transplant BMSCs with the pedicled greater omentum for regeneration of spinal cord after SCI compared with transplanting BMSCs alone. This method results in better locomotor outcomes and axonal regeneration.

Preventing and localizing esophagogastric anastomosis leakage by sleeve-wrapping of the pedicled omentum

AIM: To develop a technique of sleeve-wrapping the pedicled omentum around the esophagogastric anastomosis for preventing and localizing leakage.

Malignant solitary fibrous tumor of the greater omentum: A case report and review of literature

BACKGROUND Malignant solitary fibrous tumors(SFTs)account for 15%-20%of all SFTs,and malignant SFTs arising from the greater omentum are extremely rare.Most malignant SFTs of the greater omentum are diagnosed via pathological examinations after surgery.In this study,we report a case of malignant omental SFT and review the published literature on this rare malignancy.CASE SUMMARY A 64-year-old female presented with an abdominal mass,and underwent exploratory surgery,during which a huge tumor originating from the greater omentum and intraperitoneal implants were identified and resected.The results of the pathological examination,immunohistochemistry staining,and gene sequencing led to the diagnosis of malignant SFT of the greater omentum.The patient died one and a half years later due to tumor recurrence and metastasis.CONCLUSION This is the first report of the application of gene sequencing in the diagnosis of malignant SFTs of the greater omentum.

Greater omentum gastrointestinal stromal tumor with PDGFRA-mutation and hemoperitoneum

Although gastrointestinal stromal tumor(GIST) occurs generally in the digestive tract,omental GIST is very rare.We report the first case of an adult greater omental GIST with a new platelet-derived growth factor receptor α gene(PDGFRA)-mutation with hemoperitoneum.A 43-year-old man was admitted to our hospital complaining of acute abdominal pain.Abdominal contrast-enhanced computed tomography revealed a huge mass in the right abdominal cavity,and a large accumulation of fluid in the pelvic cavity,suggesting hemoperitoneum.We diagnosed the rupture as an intra-abdominal tumor,and an emergency tumorectomy was performed with resection of the greater omentum.This tumor was located in the distal right side ofthe greater omentum,and showed no continuity with the gastric wall.The tumor occurred primarily in the greater omentum.The resected tumor was about 19 cm × 12 cm × 14 cm in diameter,and weighed 1529 g.Histologically,the tumor was composed of epithelioidshaped cells with high cellularity,and was positive for CD117 and CD34,and negative for S-100,α-smooth muscle actin.The mitosis was 6/50 under high power field.This case showed exon 18 mutation of PDGFRA with 846(Asp to Glu) substitution,848(Asn to Lys) substitution.This is the first report of this PDGFRA mutation in omental GIST,and this might play an important role in the tumorigenesis of this case.Based on these findings,the tumor was diagnosed as high risk GIST primarily occurring in the greater omentum.The patient was treated with imatinib at a dose of 400 mg/d as adjuvant chemotherapy,and has been followed up for 24 mo with no evidence of recurrence.

Myotomy with Omentum Covering and Cardio-valvoplasty for Treatment of Achalasia

Thirty one cases of the achalasia underwent myotomywith omentum covering and cardio-valvoplasty from 1983to 1988 at our hospital. Follow-up study, one to 4 yearspostoperatively, showed that 29 cases (93.5%) of themwith excellent results, only 2 cases(6.5%)showed slightdysphagia. The advantages of this procedure are as fol-lows: 1. relief of obstruction at lower end of esophagusand cardia preventing the recurrence of stenosis; 2. pre-vention of occurence of reflux esophagitis; 3. no altera-tion of normal anatomy of the esophagocardia region andno intervention of mucosa; 4. simplicity and safety ofthis procedure.

Autologous omentum transposition for regeneration of a renal injury model in rats

Background:After renal trauma,surgical treatment is vital,but sometimes there may be loss of function due to fibrosis.This study aimed to evaluate the effect of autologous omentum flaps on injured renal tissues in a rat model.Methods:A total of 30 Wistar albino rats were included and randomly divided equally into a control group and four intervention groups.Iatrogenic renal injuries were repaired using a surgical technique(primary repair 1 group and primary repair 2 group)or transposition of the autologous omentum(omentum repair 1 group and omentum repair 2 group).Blood samples were taken preoperatively and on the 1st and 7th postoperative days in all groups and on the 18th postoperative day in the control and two intervention groups.All rats were sacrificed on the 7th or 18th day postoperatively,and their right kidneys were taken for histopathological evaluation.Results:The mean urea level significantly decreased from day 1 to day 7 and from day 1 to day 18 in the omentum repair 2 group(P=0.005 and P=0.004,respectively).There were no other significant changes in urea or creatinine levels within the intervention groups(P>0.05).There was no significant correlation between the urea and creatinine levels and the histological scores(P>0.05).The primary repair 1 and 2 groups had significantly higher median granulation and inflammation scores in the kidney specimen than the control and omentum repair groups(P<0.05).The omentum repair 2 group had significantly lower median granulation and inflammation scores in the surrounding tissues than the primary repair 2 group(P<0.05).The completion score for the healing process in the kidney specimen was significantly higher in the omentum repair groups than in the primary repair groups(P<0.05).The omentum repair 2 group had significantly lower median granulation and inflammation scores in the surrounding tissues than the primary repair 2 group(P<0.05).Granulation degree in the kidney specimen was strongly and positively correlated with the inflammation degree(r=0.824,P<0.001)and foreign body reaction in the kidney specimen(r=0.872,P<0.001)and a strong and negative correlation with the healing process completion score in the kidney(r=−0.627,P=0.001).Inflammation degree in the kidney specimen was strongly and positively correlated with the foreign body reaction in the kidney specimen(r=0.731,P=0.001)and strongly and negatively correlated with the healing process completion score in the kidney specimen(r=−0.608,P=0.002).Conclusion:Autologous omentum tissue for kidney injury repair attenuated inflammation and granulation.Additionally,the use of omental tissue to facilitate healing of kidney injury may theoretically lead to a more effective healing process and reduced fibrosis and tissue and function loss.

Ureteroscopic holmium laser to transect the greater omentum to remove an abdominal drain:Four case reports

BACKGROUND Drainage tube removal is difficult when the greater omentum becomes incarcerated in the drainage tube through the side holes.Currently,known removal methods are either ineffective or will cause additional damage to the patient in a secondary operation.Ureteroscopy and the holmium laser have been used in various surgical techniques in urology,and in theory,they are expected to be a good strategy for solving the problem of tissue incarceration.CASE SUMMARY Four patients diagnosed with difficult removal of an abdominal drainage tube following abdominal surgery are reported.All patients underwent surgery to remove the incarcerated greater omentum in the drainage tube using a holmium laser and a ureteroscope,and a new 16-F drain was then placed in the abdominal or pelvic cavity.The efficacy of this technique was evaluated by intraoperative conditions,success rate,and operating time;safety was evaluated by perioperative conditions and the probability of postoperative complications.All four operations went smoothly,and the drains were successfully removed in all patients.The average operating time was 24.5 min.Intraoperatively,the average irrigation volume was 892.0 mL,the average drainage volume was 638.5 mL,and no bleeding or damage to surrounding tissues was observed.Postoperatively,the average drainage volume was 32.8 mL and the new drains were removed within 36 h.All patients were able to get out of bed and move around within 12 h.Their visual analogue pain scores were all below 3.The average follow-up duration was 12.5 mo and no complications such as fever or bleeding were noted.CONCLUSION Ureteroscopic holmium laser surgery is an effective,safe and minimally invasive technique for removing drains where the greater omentum is incarcerated in the abdominal drain.

PRELIMINARY STUDY OF OMENTUM TRANSPOSITION TO BRAIN FOR TREATMENT OF ALZHEIMER’S DISEASE

Objective To learn the effect of omemtum transposition to the brain of patients with Alzheimer’s disease. Methods Ten consecutive patients, aged 58-81 years old, underwent graft of their elongated pedicled omentum onto their left frontal-temperal-parietal cerebral cortex. Those patients, who had more than five years of dementia with low mini mental-state examination (MMSE) scores of 2-15, were diagnosed by a neurologist. All subjects underwent single photon evoked computer tomography (SPECT) pre- and post-operatively. SPECT results were analyzed semi-quantitatively by calculation of the left/right radioactivity counts symmetry index (Si). The patients were followed up to one year. The outcome was evaluated by the neurologist with a modified scale of activities of daily living (mADL) as well as the MMSE. Results Three months following the surgery, the Si of SPECT increased from (98.7±1.9)% to (103.9±2.3)% (P=0.0307). The neurological and neuropsychological testing scores increased insignificantly during the follow-up period. By the one year, the MMSE score rose from 8.7±1.4 to 10.7±1.8(P>0.05), while the mADL from 13.3±1.8 to 16.9±2.0 (P>0.05). One of the patients suffered a heart attack, two had epileptic episodes postoperatively. Conclusion We believe that omental transposition to the brain augments cerebral blood flow, which might be helpful to decelerate the processing of Alzheimer’s disease. However, it is still a potentially risky procedure for the elderly.

Greater omentum in reconstruction of refractory wounds

Objective: To evaluate the clinical efficacy of greater omentum in reconstruction of refractory wounds. Methods: From August 1988 to May 2001, 20 patients with refractory wound underwent pedicle or microvascular free transfer of the greater omentum. Indications of surgery were electrical injury of the wrist and hand in 9 patients, electrical injury of the scalp and cranial bones in 3, avulsion injury of the scalp in 2, radiation-related ulcer of the chest wall in 2, ulcer and osteomyelitis following resection of the sternum sarcoma in 1, electrical injury of the abdomen in 1, bone and soft tissue defects following compound fracture of the leg in 1, and extensive scar and ulcer of the leg and footdrop following trauma in 1. Severe infection and extensive tissue necrosis were present prior to surgical operation in 12 patients. Eleven patients were treated with pedicled omental flaps, and 9 patients with free omental flaps. The size of the omental flaps ranged from 20 cm&times;12 cm to 38 cm&times;23 cm. Results: All the omental flaps survived. Healing at the first intention of the wounds was achieved in 17 cases. The on-top skin grafts resulted in partial necrosis of lipid liquefaction developed in the omentum and healed with dressing change in 2 cases. A sinus tract of osteomyelitis occurred in one case and healed after delayed excision of the necrosed bone. Follow-up study of all cases from 3 to 24 months showed no recurrent wounds and post-operative abdominal complication. Recovery with acceptable appearance and restoration of function was satisfactory. Conclusions: Greater omentum provides a well-vascularized tissue with lymphatic ducts for wound coverage. It has strong resistance against infection. It is very malleable and can be molded easily. Therefore it is an ideal tissue in filling cavities and repairing defects, especially in covering large and irregular defects that can not be treated with skin or muscle flaps.

难复性腹股沟斜疝导致继发性大网膜扭转坏死1例

目的增加对大网膜扭转坏死的认识,提高对腹股沟疝择期手术治疗的重视程度。方法回顾性分析宜宾市第一人民医院2023年1月收治1例难复性腹股沟斜疝导致继发性大网膜扭转坏死的罕见急腹症。结果以“下腹痛”为首要表现就诊,完善腹部CT检查后行开腹探查手术,术中行疝内容物松解复位、坏死大网膜切除,并行传统疝修补,术后恢复良好出院,随访6个月腹股沟疝未见复发。结论大网膜扭转坏死是一种罕见急腹症,可继发于腹股沟疝;成人腹股沟疝一经确诊,建议积极行手术治疗。

Therapeutic effect of medical glue combined with the great omentum in severe tunica muscularis injury

Twenty-seven patients with severe colon trauma treated in the Shaoxing People’s Hospital from 1995 to 2006 were retrospectively analyzed.The patients with severe tunica muscularis injury were treated by med-ical glue combined with the greater omentum during operations.The initial result was encouraging.All patients were cured with no anastomotic leakage or abs-cess.Therefore,reasonable use of medical glue combined with the greater omentum can not only improve the cur-ative rate but also reduces postoperative complications for patients with colon injury.

A case of abdominal abscess after simultaneous omentum intraomental bio-scaffold islet-kidney transplantation

Compared with patients who undergo renal and islet transplantation sequentially,simultaneous omentum intraomental bio-scaf-fold islet-kidney transplantation in patients with type 1 diabetes complicated by renal failure has the advantages of donor homolo-gation,less trauma,lower cost,and easier acceptance by patients.Omentum intraomental bio-scaffold islet has been gradually applied in clinical practice,and rare clinical complications have been reported.Here we report a case of abdominal abscess associated with extended-spectrum β-lactamase in a patient who underwent simultaneous omentum intraomental bio-scaffold islet-kidney transplantation;the islet grafts remained partially functional after appropriate anti-infective treatment.

Omentum transposition for treatment of Alzheimer disease in China

Background:A paper was published in a Chinese medical journal that suggested that the placing of an intact vascularized omental pedicle would increase cerebral blood flow and could decelerate the development of Alzheimer's disease.However,the paper showed limited support for the operation.The purpose of this paper is to suggest that the lack of enthusiasm for the operation may deserve re-evaluation.Method:The operation that was evaluated required an intact omental pedicle to be placed directly on the brain in order to increase the blood flow to the brain.The omentum is brought from the abdominal cavity up to the brain where it is simply laid resulting in a large volume of blood to flow into the cerebral tissue.Results:The Chinese paper demonstrated relatively poor results in the Alzheimer patients.It is believed that the poor results were probably due to the results of the patients age,the length of time they had Alzheimer disease (5 or more years),but especially their low mini-mental state examination results-some as low as 2.Conclusion:The paper being presented will suggest the possible benefit of omental transposition in Alzheimer patients when there is a successful choice of suitable candidates for the procedure.