Omentum and basic fibroblast growth factor in healing of chronic gastric ulcerations in rats

Is omentectomy necessary in the treatment of benign or malignant abdominal pathologies? A systematic review

BACKGROUND

The omentum is an organ that is easily sacrificed during abdominal surgery. The scope of omentectomy and whether a routine omentectomy should be performed are still unknown.

AIM

To review the literature in order to determine the physiological functions of the omentum and the roles it plays in pathological events in order to reveal the necessity for removal and preservation of the omentum.

METHODS

A clinical review of the English language literature based on the MEDLINE (PubMed) database was conducted using the keywords: “abdomen”, “gastrointestinal”, “tumor”, “inflammation”, “omental flap”, “metastasis”, “omentum”, and “omentectomy”. In addition, reports were also identified by systematically reviewing all references in retrieved papers.

RESULTS

The omentum functions as a natural barrier in areas where pathological processes occur in the abdominal cavity. The omentum limits and controls inflammatory and infectious pathologies that occur in the abdomen. It also aids in treatment due to its cellular functions including lymphatic drainage and phagocytosis. It shows similar behavior in tumors, but it cannot cope with increasing tumor burden. The stage of the disease changes due to the tumor mass it tries to control. Therefore, it is considered an indicator of poor prognosis. Due to this feature, the omentum is one of the first organs to be sacrificed during surgical procedures. However, there are many unknowns regarding the role and efficacy of the omentum in cancer.

CONCLUSION

The omentum is a unique organ that limits and controls inflammatory processes, foreign masses, and lesions that develop in the abdominal cavity. Omental flaps can be used in all anatomical areas, including the thorax, abdomen, pelvis, and extremities. The omentum is an organ that deserves the title of the abdominal policeman. It is generally accepted that the omentum should be removed in cases where there is tumor invasion. However, the positive or negative contribution of omental resection in the treatment of abdominal pathologies should be questioned.

The Greater Omentum-A Vibrant and Enigmatic Immunologic Organ Involved in Injury and Infection Resolution

Once thought of as an inert fatty tissue present only to provide insulation for the peritoneal cavity, the omentum is currently recognized as a vibrant immunologic organ with a complex structure uniquely suited for defense against pathogens and injury. The omentum is a source of resident inflammatory and stem cells available to participate in the local control of infection, wound healing, and tissue regeneration. It is intimately connected with the systemic vasculature and communicates with the central nervous system and the hypothalamic pituitary adrenal axis. Furthermore, the omentum has the ability to transit the peritoneal cavity and sequester areas of inflammation and injury. It contains functional, immunologic units commonly referred to as "milky spots" that contribute to the organ's immune response. These milky spots are complex nodules consisting of macrophages and interspersed lymphocytes, which are gateways for the infiltration of inflammatory cells into the peritoneal cavity in response to infection and injury. The omentum contains far greater complexity than is currently conceptualized in clinical practice and investigations directed at unlocking its beneficial potential may reveal new mechanisms underlying its vital functions and the secondary impact of omentectomy for the staging and treatment of a variety of diseases.

The Influence of "Omental Cake" Presence on the Completeness of Cytoreduction in Advanced-stage Ovarian Cancer

BACKGROUND/AIM

The presence of "omental cake" has been considered since long as a negative prognostic factor in patients diagnosed with advanced-stage ovarian cancer. The aim of this paper was to study the impact of "omental cake" presence on the perioperative outcomes in advanced-stage ovarian cancer.

PATIENTS AND METHODS

Between 2015 and 2020, 85 patients were submitted to surgery for advanced-stage ovarian cancer.

RESULTS

Among cases diagnosed with "omental cake" the rate of complete cytoreduction was significantly diminished when compared to cases in which this entity was not revealed. In the meantime, the presence of omental cake among cases in which complete debulking was achievable was significantly associated with a higher number of digestive resections when compared to the other cases submitted to surgery and in which tumoral transformation of the omentum was encountered.

CONCLUSION

The presence of "omental cake" is associated with a higher rate of incomplete resections. However, in cases in which complete debulking was achieved, the presence of omental cake was associated with a significantly higher number of digestive tract resections.

Wavy Floating Greater Omentum Findings Are Useful for Differentiating the Etiology of Fetal Ascites

The greater omentum is an apron-like peritoneal mesothelial sheet that was described by ultrasound as a floating fluid-filled viscus in ascites during the fetal period. To examine the association between the etiology of fetal ascites and ultrasound findings of the greater omentum, a retrospective study was conducted. Ultrasound findings of fetal omentum were defined as follows: (1) a cyst-like shape with a thin membrane observed as wavy in the ascites, (2) beside the stomach and below the liver, and (3) no blood flow noted on color Doppler. Eleven pregnancies had fetal ascites. A fetal greater omentum was confirmed in eight cases in which ascites were caused by non-peritonitis: fetal hydrops (n = 4), congenital cytomegalovirus infection (n = 2), idiopathic chylous ascites (n = 1), and unknown cause (n = 1). Of these eight cases, no abdominal surgical management was required in three live babies. However, a fetal greater omentum was not confirmed in all three cases of meconium peritonitis. It was suggested that the finding of the greater omentum can be an important clue for estimating the pathophysiological etiology of fetal ascites and helping with postnatal management. It should be reasonable to add the finding of the greater omentum to the detailed ultrasound examination checklist.

Creation of a Continent Urinary Bladder Reservoir Vascularized by Omentum as a Possible Surgical Option for Canine Trigonal/Urethral Urothelial Carcinoma

Surgical procedures that maintain continence with minimal complication following resection of trigono-urethral urothelial carcinoma (UC) are limited in canines; therefore, palliative options are often pursued. A feasible tumor resection option may improve disease control and survival. The study's objective was to evaluate a continent urine reservoir created from the urinary bladder body and vascularized solely by omentum. We hypothesized that a viable urine reservoir could be created, and staged omentalization would provide improved vascularity. Nine normal female Beagles were randomized to one of three groups. Group A urinary bladders were transected cranial to the ureteral papillae to create a closed bladder vesicle which was concomitantly omentalized. Group B underwent omentalization two weeks prior to vesicle creation. Based on Group A and B results, Group C underwent neoureterocystostomy and omentalization followed by neoreservoir formation and tube cystostomy 2 weeks later. Serial ultrasounds and histopathology confirmed adequate omental neovascularization in Groups B and C with continent Group C neoreservoirs maintained for 2 months. Some pylectasia and ureteral dilation was documented in all Group C dogs at variable timepoints. Progressive hydroureteronephrosis developed in 2/6 kidneys. Transient azotemia was noted in only 1 Group C dog, although all developed treatable urinary tract infections. The sample size is limited, and the efficacy of this technique in providing disease control for UC is unknown. However, this novel option could allow for primary UC resection while providing continence and limiting complications. Postoperative local or systemic adjuvant therapy, ultrasonographic neoreservoir monitoring, and BRAF analysis would be indicated.

The role of omentectomy in the surgical treatment of uterine serous carcinoma

OBJECTIVE

The aims of this study were to assess the role of omentectomy in the staging of uterine serous carcinoma (USC) and to evaluate its impact on patient outcomes.

STUDY DESIGN

Patients diagnosed with USC at the First Affiliated Hospital of Sun Yat-sen University of China were retrospectively reviewed. The clinicopathological characteristics and survival data of 187 patients were analyzed. Risk factors for omental metastasis were evaluated. Kaplan-Meier survival curves were used to compare survival status and the presence of omental metastasis.

RESULTS

We found that 35 of 187 patients (18.7%) had omental metastases. Omental metastasis was significantly associated with adnexal involvement (40.0% vs 19.1%, P = 0.008, OR 2.828, 95% CI 1.286-6.218). Multivariate analysis showed that in addition to lymph node metastases and suboptimal surgery, omental metastasis in USC remained an independent predictor of decreased PFS and OS (PFS, HR 1.48, 95% CI 1.14-4.63, P = 0.024; OS, HR 1.39, 95% CI 1.04-3.60, P = 0.043).

CONCLUSIONS

The incidence of omental metastasis is not low in patients with USC. Visual assessment and omental biopsy may be insufficient for recognizing occult metastases. Omentectomy should be part of the staging surgery in USC patients because it provides additional information about survival. Prospective studies are needed to confirm these results.

Omentum a powerful biological source in regenerative surgery

The Omentum is a large flat adipose tissue layer nestling on the surface of the intra-peritoneal organs. Besides fat storage, omentum has key biological functions in immune-regulation and tissue regeneration.

Omentum biological properties include neovascularization, haemostasis, tissue healing and regeneration and as an in vivo incubator for cells and tissue cultivation. Some of these properties have long been noted in surgical practice and used empirically in several procedures.

In this review article, the author tries to highlight the omentum biological properties and their application in regenerative surgery procedures. Further, he has started a process of standardisation of basic biological principles to pave the way for future surgical practice.

Anastomotic reinforcement with omentoplasty reduces anastomotic leakage for minimally invasive esophagectomy with cervical anastomosis

Purpose

Anastomotic leakage is the most feared postoperative complication after esophagectomy. Omentoplasty, wrapping the omentum around the alimentary tract anastomosis, is thought to decrease the anastomotic leakage rate. The purpose of this clinical study is to investigate the use of omentoplasty to reinforce cervical esophagogastrostomy after minimally invasive esophagectomy (MIE).

Patients and methods

In this retrospective study, the data of 160 consecutive patients who underwent cervical esophagogastrostomy after MIE between September 2012 and May 2015 were analyzed, 87 who underwent omentoplasty (group A) and 73 who did not undergo omentoplasty (group B). The primary outcome was the incidence of anastomotic leakage and anastomotic strictures after the operation. Secondary outcomes were other complications and mortality rate. Univariate and multivariate analysis of variables associated with an increased risk for anastomotic leak was performed.

Results

The median age was 61 years (range, 37-82 years). The anastomotic leakage rates were 4.6% (4/87) in group A and 15.1% (11/73) in group B (P = 0.023). There was no statistical significance in anastomotic stricture rates between group A (6.9%) and group B (9.6%; P = 0.535). No difference was noted in other complications between the groups. There was a trend toward lower leak-associated mortality rates for group A (0%) compared with that for group B (4.1%).

Conclusion

Cervical esophagogastrostomy with omentoplasty is more effective than esophagogastrostomy without omentoplasty for the prevention of anastomotic leakage in MIE with cervical anastomosis. Omentoplasty could be used as an adjunct technique to reduce the incidence of anastomotic leakage in cervical esophagogastrostomy following MIE.

Intersphincteric completion proctectomy with omentoplasty for chronic presacral sinus after low anterior resection for rectal cancer

AIM

This study aimed to determine the clinical outcome of salvage surgery without restoring continuity for symptomatic chronic presacral sinus after low anterior resection (LAR) for rectal cancer.

METHOD

Out of a prospective cohort of 46 patients with chronic presacral sinus (> 1 year after LAR), 27 underwent completion proctectomy with omentoplasty between January 2005 and July 2014.

RESULTS

The initial treatment for rectal cancer included neoadjuvant radiotherapy in 26 (96%) patients. Besides a chronic presacral sinus, a secondary fistula was present in 15 (56%) patients. Definitive salvage surgery was performed after a median of 40 (12-350) months from the primary resection. The median hospital stay after single- and multiple-stage salvage surgery was 11 and 17 days. Postoperative complications occurred in 44% of patients. The re-intervention rate was 33% with a range of 1-10 interventions per patient. During a median follow-up of 20 (4-45) months from salvage surgery, healing of the chronic presacral sinus occurred in 78% of patients, with a healing rate after single- and multiple-stage procedures of 88% and 64% respectively (P = 0.19).

CONCLUSION

Patients with a symptomatic chronic presacral sinus after LAR for rectal cancer, in whom restoration of continuity is not intended, can be effectively managed by completion proctectomy with complete debridement of the sinus and fistula tracts followed by an omentoplasty to fill the presacral cavity, preferably as a single-stage procedure.

Is a More Comprehensive Surgery Necessary in Patients With Uterine Serous Carcinoma?

Objective

Uterine serous carcinoma (USC) is an aggressive histologic subtype of endometrial cancer that shares similarities to serous ovarian cancer, with a propensity for spread to the upper abdomen, a high recurrence rate, and a poor prognosis. The aim of this study was to determine whether the traditional surgical staging procedure for endometrial cancer was adequate for USC or whether a more extensive surgery, similar to the staging procedure for ovarian cancer, needs to be performed. Specifically, the roles of omentectomy and sentinel lymph node (SLN) mapping were evaluated.

Methods

We retrospectively identified cases of presumed clinical stage I USC at our institution from April 2005 to March 2014. Medical records were reviewed for the following information: age at diagnosis, preoperative imaging, operative findings, surgical procedure, and final histology with definitive International Federation of Gynecology and Obstetrics stage.

Results

A total of 39 patients with presumed clinical stage I USC were identified. According to the final pathology report, the surgical stage was as follows: 17 stage IA (44%), 8 stage IB (20%), 3 stage II (8%), 2 stage IIIA (5%), 6 stage IIIC1 (15%), 1 IIIC2 (3%), and 2 stage IVB (5%). Therefore, 14 patients (36%) were surgically upstaged, but none of the patients had their clinical disease upstaged by virtue of finding microscopic metastatic disease in an otherwise normal-looking omentum. Sentinel lymph node mapping was performed in 19 patients (42%). Sensitivity and negative predictive value of SLN mapping were 100% when at least 1 SLN was identified.

Conclusions

The detection of microscopic disease in radiologically and clinically normal-appearing omentum seems to be rare in USC. Sentinel lymph node mapping seems to be valuable in the serous subtype of endometrial cancer. A less extensive surgery may be possible in patients with USC as it seems to provide the same information as a more extensive surgery.

Omentoplasty in preventing anastomotic leakage of oesophagogastrostomy following radical oesophagectomy with three-field lymphadenectomy

OBJECTIVES

Anastomotic leakage is a major cause of mortality in oesophageal surgery. Whether omentoplasty after oesophagogastrostomy could reduce anastomotic leakage is still controversial. The aim of this study is to investigate the function of omentoplasty to reinforce cervical oesophagogastrostomy after radical oesophagectomy with three-field lymphadenectomy.

METHODS

A total of 184 patients who underwent radical oesophagectomy with three-field lymphadenectomy took part in this prospective study. Patients were randomized to receive either the omentoplasty or non-omentoplasty. In the omentoplasty group, the omentum was wrapped around the oesophagogastric anastomosis after oesophagogastrostomy. Age, gender, location of carcinoma, stage, body mass index, diabetes, coronary artery disease, peripheral vascular disease and performance of omentoplasty were recorded. The anastomotic leakage and stricture and recurrence site were followed up for three years after the operation.

RESULTS

The two groups were comparable in terms of age, gender, location of carcinoma, stage, body mass index, diabetes, coronary artery disease and peripheral vascular disease (P > 0.05). In contrast to the non-omentoplasty group with a postoperative anastomotic leakage rate of 9.8%, the omentoplasty subjects demonstrated a significantly lower rate of 3.3% (P < 0.05). No lethal leakage was found in the omentoplasty group, while two non-omentoplasty patients developed incurable empyema and mediastinitis due to leakage and ultimately died. The rate of incidence of anastomotic stricture in the omentoplasty and non-omentoplasty groups were 4.3% and 2.2% respectively. Of the five cases of death during the hospital stay, two were found in the omentoplasty group and three in non-omentoplasty. There was no significant difference of lethal leakage, stricture and death rate between the two groups (P > 0.05). The hospital stay was significantly longer for non-omentoplasty patients, compared with that for the omentoplasty subjects (P < 0.05). Tumour recurrence in lymphatic- or haematogenous metastasis was similar in both groups (P > 0.05).

CONCLUSION

Omentoplasty may prevent anastomotic leakage of oesophagogastrostomy following radical oesophagectomy with three-field lymphadenectomy.

Autogenous greater omentum, as a free nonvascularized graft, enhances bone healing: an experimental nonunion model

Reconstruction of vascularity is an early event in fracture healing and upregulation of angiogenesis may therefore promote the formation of bone. We have investigated the potentiality of autogenous free nonvascularized greater omentum to stimulate the formation of bone in an experimental hypertrophic nonunion model. Twelve dogs assigned into two identical groups underwent a standard nonunion operation. In the experimental group, this was followed by application of autogenous greater omentum as a free nonvascularized graft around the osteotomy gap. Radiographic assessments were conducted time-sequentially until euthanasia 16 weeks after surgery. Histological analysis was performed on the mid-radial diaphysis containing the 4-month-old osteotomy site. Radiological and histological properties of the group treated with free transplant of the greater omentum revealed complete union. In contrast, there was no evidence indicating union in the control group. Analyses of the radiological and histological scores confirmed that osteotomies treated with free transplant of the autogenous greater omentum had united, whereas the osteotomies of the control group failed to unite. Significant differences between the mean values for radiological and histological-grading score in the control and experimental groups were detected (p < 0.05). We showed that free graft of autogenous greater omentum could stimulate the formation of competent bone in an environment deprived of its normal vascularization. Hence, it could be recommended to enhance healing when the fractures are at risk of nonunion.

Novel role for mast cells in omental tissue remodeling and cell recruitment in experimental peritoneal dialysis

Because of its dynamic structure, the omentum plays a key role in the immunity of the peritoneal cavity by orchestrating peritoneal cell recruitment. Because mast cells accumulate in the omentum upon experimental peritoneal dialysis (PD) and may produce angiogenic/profibrotic factors, it was hypothesized that mast cells mediate omental tissue remodeling during PD. Daily treatment with conventional PD fluid (PDF) for 5 wk resulted in a strong omental remodeling response, characterized by an approximately 10-fold increase in mast cell density (P < 0.01), an approximately 20-fold increase in vessel density (P < 0.02), an approximately 20-fold increase in the number of milky spots (P < 0.01), and a four-fold increase in submesothelial matrix thickness (P < 0.0003) in wild-type rats. In contrast, all PDF-induced omental changes were significantly reduced in mast cell-deficient Ws/Ws rats or in wild-type rats that were treated orally with a mast cell stabilizer cromoglycate. A time-course experiment showed mast cell accumulation immediately before the formation of blood vessels and milky spots. Functionally, PDF evoked a peritoneal cell influx, which was significantly reduced in Ws/Ws rats (P < 0.04) and in wild-type rats that were treated with cromoglycate (P < 0.03). Cromoglycate treatment also completely prevented PDF-induced omental adhesions to the catheter tip (P = 0.0002). Mesothelial damage, angiogenesis, and fibrosis of mesentery and parietal peritoneum as well as glucose absorption rate and ultrafiltration capacity proved to be mast cell independent. Data strongly support the hypothesis that mast cells mediate PDF-induced omental tissue remodeling and, subsequently, peritoneal cell influx and adhesion formation, providing therapeutic possibilities of modulating omental function.

Attenuation of pain perception after transposition of the greater omentum to the cauda equina region of rats--a preliminary observation

BACKGROUND

This paper addresses a specific experimental design to suggest the possible role of the greater omentum in the modulation of pain in rats.

METHODS

Fifteen male Sprague-Dawley rats weighing between 275 and 325 g were selected. The animals were randomized and then anesthetized with pentobarbital (35 mg/kg) and divided into three groups: (1) sham: laparotomy followed by laminectomy with exposure of the spinal epidural space (n=5); (2) transposition of pedicled omentum (n=5) to the cauda equina epidural space; and (3) transposition of pedicled omentum (n=5) to the cauda equina intradural space. The animals were operated upon and once more randomized by an independent investigator, so that the groups were thought to be similar during post-operative testing. The latency of paw withdrawal to noxious heat stimulation was tested and the values (seconds) plotted for 1, 3, 6, 11, 14 and 30 days after surgery. Randomization codes were open after the animals were euthanized. The analysis of variance (ANOVA) without replication was applied for each of the dataset and comparisons established among the different study groups involved. The omenta were removed and standard immunohistochemistry was performed for gamma-amino-butyric acid (GABA), serotonin, calcitonin-gene related protein (CGRP), vascular intestinal peptide (VIP) and Met-enkephalin.

RESULTS

The response to high heating rates of stimulation favored intradural versus sham and epidural omental transpositions. High and low noxious heat stimulation suggested an increased threshold to noxious stimulation after the 3 and 30 days of omental transposition. In the low heat stimulation series, responses were comparatively higher than in the sham animals.

CONCLUSIONS

The suggested increased threshold of response to noxious stimulation after transposition of the greater omentum onto the spinal cord of rats suggested a novel role of the omentum and a potential future application in the clinical arena.

A Single Local Application of Recombinant Human Basic Fibroblast Growth Factor Accelerates Initial Angiogenesis During Wound Healing in Rabbit Ear Chamber

Local angiogenic therapy with recombinant human basic fibroblast growth factor (rhbFGF) has been used to promote wound healing. To obtain useful information for the development of optimal angiogenic therapy, we chronologically evaluated the effects of a single local application of rhbFGF on angiogenesis in a rabbit ear chamber model of wound healing by observing the subcutaneous vessel bed intravitally. New vessel formation during wound healing was macroscopically and microscopically evaluated for 5 wk. Each rabbit ear chamber received a single dose of 6 microg rhbFGF (treatment B1: n = 13), 18 microg rhbFGF (treatment B2: n = 16), or physiological saline as control (n = 13). At 1 wk the newly vascularized area was significantly larger in groups B1 and B2 than in control. At 2 wk, the vascularized areas in groups B1, B2, and control were similar. At 5 wk, the percentage of rabbits with complete vascularization was significantly larger in group B1 than in control. Capillary density at 5 wk was similar among the three groups. These results suggest that locally applied rhbFGF accelerated angiogenesis during early wound healing in rabbits; however, this effect was transient and no increase in capillary density occurred at the completion of vascularization.

Effects of growth factors and trefoil peptides on migration and replication in primary oxyntic cultures

Restitution, the lateral migration of cells over an intact basement membrane, maintains mucosal integrity. We studied the regulation of migration and proliferation of enzyme-dispersed canine oxyntic mucosa cells in primary culture. Confluent monolayers were wounded and cultured in serum-free medium, and cells migrating into the wound were counted. [3H]thymidine incorporation into DNA was studied using subconfluent cultures. Considerable migration occurred in untreated monolayers; however, epidermal growth factor (EGF), transforming growth factor (TGF)-alpha, basic fibroblast growth factor (bFGF), insulin-like growth factor I (IGF-I), two trefoil peptides, and interleukin (IL)-1beta further enhanced migration. The specific EGF receptor (EGFR) monoclonal antibody, MAb-528, inhibited both basal and TGF-alpha- or IL-1beta-stimulated migration, but not the response to trefoil peptide, bFGF, or IGF-I. Exogenous TGF-beta inhibited cell proliferation but did not alter migration. Immunoneutralization with anti-TGF-beta blocked the response to exogenous TGF-beta and produced a small enhancement of basal thymidine incorporation but did not attenuate basal or TGF-alpha-stimulated migration. In conclusion, endogenous EGFR ligands regulate proliferation and migration. TGF-beta inhibits mitogenesis; it did not upregulate migration in these cultures. Although bFGF, IGF-I, and IL-1beta enhance gastric epithelial migration, only IL-1beta acted in a TGF-alpha-dependent fashion.

Effects of growth factors on acid-induced damage to rat gastric epithelial cells

We previously established a model of cell damage induced by an acidified medium in the rat gastric epithelial cell line RGM1. Treatment of the cells with epidermal growth factor (EGF, 1-10 ng/ml) for 4 h prevented acid-induced cell damage in a concentration-dependent manner. In contrast, basic fibroblast growth factor (1-10 ng/ml) and platelet-derived growth factor BB (1-10 ng/ml) had no effect on cell damage. EGF did not affect DNA synthesis by the cells for 4 h. Pretreatment of the cells with cycloheximide (10 micrograms/ml) for 1.5 h before EGF treatment significantly attenuated the cytoprotective effect of EGF by > 50%. Replacement of Na+ with K+ in the acidified medium totally abolished the effect of EGF. Co-incubation with amiloride (1 mM) had no influence on the protective effect of EGF. These results indicate that the cytoprotective effect of EGF appears to involve both the activation of amiloride-resistant Na+/H+ exchangers and the synthesis of a new protein related to Na+/H+ exchangers.

Omentum-enhanced reconstruction of chronic nonhealing wounds in cats: techniques and clinical use

The greater omentum was used to aid in the reconstruction of nonhealing wounds in five cats. In each cat the cause of the nonhealing wound could not be determined. A vascular omental pedicle was created at laparotomy by dividing the dorsal leaf of the omentum at it pancreatic attachments (four cats) or by dividing the ventral leaf at its gastric attachments (one cat). The pedicle was then passed through either the ventral or lateral body wall into the nonhealing wound via a subcutaneous tunnel. The wounds were closed over the omentum after local tissue mobilization. All the wounds healed uneventfully and have remained healed with a mean follow-up period of 2.5 years. Complications included intestinal herniation through a ventral midline exit hole (one cat), presumed abdominal fat herniation through a ventral abdominal exit hole (one cat) and seroma formation (one cat). All of the complications were treated successfully. The omentum should be considered a useful adjunct in the treatment of nonhealing wounds in cats.