Preserved viability of the isolated bowel segment, created by omentoenteropexy: a histological observation

Comparison of Survival and Safety Between Total Omentectomy and Partial Omentectomy for Gastric Cancer: A Meta-Analysis

Background: The greater omentum can limit abdominal inflammation and act as a protective cushion, but it is always involved in dissemination of gastric cancer. The purpose of this meta-analysis was to compare the survival and safety between total omentectomy and partial omentectomy for gastric cancer.

Methods: Two investigators independently conducted a systematic search of PubMed, Embase, CNKI, and Cochrane Library ranging from January 2000 to November 2020. The pooled odds ratio (ORs) and weighted mean difference (WMD) with the 95% confidence interval (95% CI) were used to assess perioperative and survival parameters.

Results: A total of 2,031 patients in 11 studies (574 patients in the partial omentectomy group and 1,457 patients in the total omentectomy group) were included. The results found shorter operation time (WMD = −25.584; P = 0.000) and less intraoperative blood loss (WMD = −47.301; P = 0.050) in the partial omentectomy group, compared to total omentectomy. There were no significant differences in terms of incidence of complications (OR = 0.770; P = 0.164), blood transfusions rates (OR = 0.269; P = 0.161), time to first flatus (WMD = 0.160; P = 0.345), hospital stay (WMD = −1.258; P = 0.087), and number of harvested lymph nodes (WMD = 1.265; P = 0.662). For the disease-free survival (OR = 0.80; P = 0.381) and overall survival, there were no statistical differences between the two procedures.

Conclusions: The partial omentectomy could reduce operation time and trended to decrease intraoperative blood loss. And the survival in patients with partial omentectomy seemed to be comparable to that of patients with total omentectomy.

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.

Cystometric analysis of the transplanted bladder

Objective

Cystometric evaluation of the bladder after autotransplant and isogeneic transplant in female rats.

Material and Methods

Two groups were constituted: (A) bladder autotransplant with two subgroups: R1 – (control) and R2 – (bladder transplant); (B) isogeneic bladder transplant with three subgroups; T1 – (control); T2–T3, two subgroups observed for 30 and 60 days after transplant, respectively. All animals underwent cystometric evaluation. Afterwards, the bladders were removed for histological study.

Results

The transplanted bladders did not show significant changes in filling/storage and emptying/micturition functions after 30 and 60 days of evolution. Upon macroscopical evaluation, there was good revascularization and the tissue was well preserved. Cystometry results: Did not show significant differences in the micturition pressure in subgroups T2-T3, but did between subgroups R1−R2, T1−T2, and T1−T3. Significant differences were verified in the micturition interval between T1−T3, T2−T3, but not between R1−R2, T1−T2. There was significant difference in the micturition duration between T1−T3 but not between R1−R2, T1−T2 and T2−T3. No fistula was noted on the suture site nor leakage of urine in the abdominal cavity or signs of necrosis or retraction were observed.

Conclusions

Transplant of the bladder was shown to be a viable procedure. The results indicate that there was structural and functional regeneration of transplanted bladders, and these results indicate that it is possible that vascular endothelium growth and neurogenesis factors are involved and activated in the process of the preservation or survival of the transplanted organ.

Are there any structural alterations in a neovascularized jejunal segment by omentoenteropexy? A histologic and immunohistochemistry study

BACKGROUND/PURPOSE

Although the bowel neovascularization by omentoenteropexy seems to be a good alternative to bowel lengthening, there were no rigorous analyses about its histologic structure and intrinsic innervation. The aim of this study was a histologic and immunohistochemical analysis of a neovascularized jejune segment (NJS) by omentoenteropexy.

METHODS

An NJS was done by omentoenteropexy in 13 Wistar rats. Seven weeks afterward, the mesentery of the NJS was ligated and divided. The NJS was separated from the normal jejunum by proximal and distal complete sections. End-to-end anatomosis was done between NJS and normal jejunum to restore bowel continuity. Twenty-six rats were sham operated. At 10 weeks, specimens were taken, and H&E, S-100 protein, and neuron-specific enolase staining were done. The muscle layer thickness, mucosae layer, and myenteric plexus were analyzed. The statistical tests were the Mann-Whitney test, Friedman's test, and Spearman's correlation.

RESULTS

There was a significant increase in NJS diameter. The muscle layers and mucosa were greater in the study group. The average number of neurons per intestinal ganglion was significantly fewer in the NJS.

CONCLUSIONS

Omentoenteropexy provoked an increase in the diameter of NJS and contributed toward a reduction of the number of neurons in the myenteric plexus of NJS.

Viability of a jejunal segment after neovascularization by omentoenteropexy

Omentoenteropexy was developed as an alternative technique to promote neovascularization in an isolated bowel segment. OBJECTIVE: The aim of the present protocol was to study the long-term viability of an isolated jejunal segment following neovascularization by omentoenteropexy. Long-term survival of a neovascularized bowel segment is an indication that the utilization of this segment as an intestinal graft can be successful. METHODS: To test the proposed surgical technique, 13 Wistar rats were subjected to laparotomy, the jejunum was exposed at 20 cm from the angle of Treitz and a pedicle of greater omentum was isolated. An incision of 6 cm was made along the antimesenteric jejunal border, exposing the submucosa. Omentoenteropexy was performed between the incision of the jejunum and the pedicle of the greater omentum. After seven weeks, the mesentery of the jejunal segment subjected to omentoenteropexy was ligated and isolated from the rest of the jejunum by a complete proximal and distal transversal section. Subsequently, an end-to-end anastomosis was performed to restore the continuity of the bowel. RESULTS: At 10 weeks from the first surgical intervention, the isolated jejunal segment subjected to omentoenteropexy was completely neovascularized and viable. CONCLUSION: No evidence of anatomical or functional intestinal obstruction was observed.

Experimental small bowel transplantation using newborn intestine in rats: I. Lipid absorption restored after transplantation of nonvascularized graft

BACKGROUND/PURPOSE

Utilizing the characters of neovascularized activity of newborn organs, the authors developed a rat model of small bowel transplantation with a free graft of newborn intestine into the recipient's omentum.

METHODS

Segmental intestine from newborn rats were grafted into the omentum without vascular anastomosis in a syngeneic combination (n = 19). The transplanted intestine was examined morphologically and electrophysiologically 4 weeks after grafting. Then, recipients' small intestine was totally substituted by the transplanted newborn intestine, and recipients' survival was recorded after orthotopical reconstruction. During the experimental periods, feces of these rats were collected, and total lipid excretion was measured. The short-gut rats, whose small bowel was totally resected, served as a control (n = 12).

RESULTS

Thirteen of 19 grafts (68.4%) were judged as a histologically mature intestine. They showed typical slow waves that were identical to those of native small intestine. After all of the mature grafts were interposed, six recipients (46.2%) survived longer than 15 weeks. Control short gut animals severely lost weight and died except for one.

CONCLUSION

Newborn intestinal transplantation could restore severe weight loss in the short-gut rats and save them.

Functional innervation of the isolated bowel segment

PURPOSE

The aim of this study is to investigate whether there might be an eventual change in the enteric nerve responses to electrical field stimulation (EFS) of the isolated bowel segment (IBS) created by omentoenteropexy.

METHODS

In the experimental group, an IBS was created in 10 rats using the omentum as the host organ by dividing of its mesentery 4 weeks later. In the control group, a jejunal loop of identical site and length to the IBS was studied in another 10 rats as normal jejunal segment. Longitudinal muscle strips were prepared from the IBSs (n 20) and the normal jejunal segments (n = 20). The effects of atropine, tetrodotoxin, L-arginine, and L-nitroarginine methyl ester (L-NAME) on the responses to transmural EFS were examined in both the IBS and normal jejunal segment using the isometric tension recording technique.

RESULTS

Transmural EFS of the IBS strips produced contractile responses. Atropine and tetrodotoxin abolished the EFS-induced contractions of the IBS. Moreover, EFS-induced contractions were increased by the application of L-NAME, and were decreased by the application of L-arginine in the IBS. Mean percent change of IBS's contraction was not found statistically different from mean percent change of normal jejunal segment's contraction on the effects of L-NAME and L-arginine.

CONCLUSION

These results suggest that the IBS, created by omentoenteropexy, produced enteric nerve responses to EFS as seen as in normal jejunal segment.

Isolated bowel segment created by omentoenteropexy: histologic findings

An isolated bowel segment (IBS) is a viable loop of bowel that is completely free of its mesenteric attachments. In this study, omentoenteropexy (OEP) was performed in 5-cm-long IBS of rats in order to provide neovascularization. Thirty-two rats were divided into four groups. After OEP, mesenteric division of the IBSs was performed at successive 1 week intervals in each group (3-6 weeks). The bowel-wall structures were histologically examined 2 days after division of the mesentery. Ischemic changes were observed in the group in which the interval was shorter than 4 weeks. In the IBSs that were supplied by the pediculated omental flap for 4 or more weeks no ischemic changes were noted in the mucosa, muscle layers, or intramural ganglia. We conclude that an IBS that preserves normal bowel structures can safely be created in the rat when its mesentery is divided 4 weeks after OEP. Physiological studies of motility and absorption can be performed and longitudinal tubularization may enable such an IBS to be used in short-bowel syndrome.