Transvaginal repair of a large chronic porcine ventral hernia with synthetic mesh using NOTES

Transvaginal placement of synthetic mesh to repair large porcine hernia using NOTES technology appears to be a feasible alternative to traditional techniques.

Background:

Ventral incisional hernias still remain a common surgical problem. We tested the feasibility of transvaginal placement of a large synthetic mesh to repair a porcine hernia.

Methods:

Seven pigs were used in this survival model. Each animal had creation of a 5-cm hernia defect and underwent a transvaginal repair of the defect with synthetic mesh. A single colpotomy was made using a 12-cm trocar for an overtube. The mesh was cut to size and placed through the trocar. A single-channel gastroscope with an endoscopic atraumatic grasper was used for grasping sutures. Further fascial sutures were placed every 5cm.

Results:

Mesh repair was feasible in all 7 animals. Mean operative time was 133 minutes. Technical difficulties were encountered. No gross contamination was seen at the time of necropsy. However, 5 animals had positive mesh cultures; 7 had positive cultures in the rectouterine space in enrichment broth or on direct culture.

Conclusion:

Transvaginal placement of synthetic mesh to repair a large porcine hernia using NOTES is challenging but feasible. Future studies need to be conducted to develop better techniques and determine the significance of mesh contamination.

Transgastric biologic mesh delivery and abdominal wall hernia repair in a porcine model

BACKGROUND AND STUDY AIMS

Incisional abdominal wall hernias currently require repair with open or laparoscopic surgery, which is associated with wound complications and recurrent hernia formation. Natural orifice transluminal endoscopic surgery (NOTES) techniques may have the potential to decrease the morbidity associated with hernia repair. The aim of this study was to repair a chronic ventral hernia with a biologic mesh placed transgastrically in a porcine model.

MATERIALS AND METHODS

Six pigs underwent creation of an incisional abdominal wall hernia. At least 4 weeks later, transgastric repair was done using an underlay biologic mesh with at least 5 cm of overlap from the hernia fascial edge. The mesh was secured with transfascial sutures and the stomach was closed with a sutured gastropexy. Pigs were evaluated 2 weeks later by laparoscopy. Pigs were sacrificed and necropsy wa s performed 4 weeks after the repair.

RESULTS

Six pigs underwent hernia repair lasting a mean (+/- SD) of 204 +/- 123 minutes, with one perioperative death. At 2 weeks after hernia repair, laparoscopy showed significant adhesions in all pigs; one pig had extensive mesh infection and was sacrificed. Necropsy on one pig at 2 weeks and four pigs at 4 weeks showed complete coverage of the hernia defect in all pigs. All pigs had mesh abscesses or a positive mesh culture.

CONCLUSION

Transgastric repair of a chronic ventral hernia is technically feasible. Difficulties with mesh delivery and infection need to be overcome before this approach can be used in humans.

In search of the best peritoneal adhesion model: comparison of different techniques in a rat model

BACKGROUND

Adhesion-related complications after abdominal surgery result in significant morbidity and costs. Results from animal studies investigating prevention or treatment of adhesions are limited due to lack of consistency in existing animal models. The aim of this study was to compare quality and quantity of adhesions in four different models and to find the best model.

MATERIALS AND METHODS

This study was approved by the University of Missouri Animal Care and Use Committee (ACUC). Forty female rats were randomly assigned to four different groups of 10 animals each. Adhesion created was performed utilizing the four techniques: Group 1 - parietal peritoneum excision (PPE), Group 2 - parietal peritoneum abrasion (PPA), Group 3 - peritoneal button creation (PBC), and Group 4 - cecal abrasion (CA). Rats were allowed to recover and necropsy was performed on postoperative d 14. Adhesions were scored by an established quantitative and qualitative scoring systems. The midline incision served as the control in each animal.

RESULTS

The four groups were not equal with respect to both quantity score (P<0.001) and quality score (P=0.042). The PBC group had the highest quantity of adhesions. The highest quality of adhesion was seen in the PPE group. A multivariate analysis carried out to quantify the performance of each model clearly demonstrated that PBC exhibited the best results in terms of both quantity and quality.

CONCLUSIONS

The button technique (PBC) is most consistent and reproducible technique for an intra-abdominal adhesion model. This model can help in the study and development of substances to prevent adhesion formation in the future.

Laparoscopic appendectomy--is it worth the cost? Trend analysis in the US from 2000 to 2005

BACKGROUND

Although laparoscopic appendectomy is widely used for treatment of appendicitis, it is still unclear if it is superior to the open approach.

STUDY DESIGN

From the Nationwide Inpatient Sample 2000 to 2005, hospitalizations with the primary ICD-9 procedure code of laparoscopic (LA) and open appendectomy (OA) were included in this study. Outcomes of length of stay, costs, and complications were assessed by stratified analysis for uncomplicated and complicated appendicitis (perforation or abscess). Regression methods were used to adjust for covariates and to detect trends. Costs were rescaled using the hospital and related services portion of the Medical Consumer Price Index.

RESULTS

Between 2000 and 2005, 132,663 (56.3%) patients underwent OA and 102,810 (43.7%) had LA. Frequency of LA increased from 32.2% to 58.0% (p < 0.001); conversion rates decreased from 9.9% to 6.9% (p < 0.001). Covariate adjusted length of stay for LA was approximately 15% shorter than for OA in both uncomplicated and complicated cases (p < 0.001). Adjusted costs for LA were 22% higher in uncomplicated appendicitis and 9% higher in patients with complicated appendicitis (p < 0.001). Costs and length of stay decreased over time in OA and LA. The risk for a complication was higher in the LA group (p < 0.05, odds ratio=1.07, 95% CI 1.00 to 1.14) with uncomplicated appendicitis.

CONCLUSIONS

LA results in higher costs and increased morbidity for patients with uncomplicated appendicitis. Nevertheless, LA is increasingly used. Patients undergoing LA benefit from a slightly shorter hospital stay. In general, open appendectomy may be the preferred approach for patients with acute appendicitis, with indication for LA in selected subgroups of patients.

Transgastric cholecystectomy using a prototype endoscope with 2 deflecting working channels (with video)

BACKGROUND

Transgastric cholecystectomy has been shown to be feasible in animal models and human case reports but cumbersome with current available instrumentation.

OBJECTIVE

To evaluate a prototype endoscope with 2 working channels with deflectors at the distal tip for performance of transgastric cholecystectomy.

DESIGN

Animal study, nonsurvival and survival.

ANIMALS

Sixteen male pigs.

SETTING

University hospital.

INTERVENTION

Transgastric cholecystectomy in 6 nonsurvival pigs by using several different dual-channel endoscopes and 10 survival pigs by using the Olympus dual-channel endoscope with an up-down deflecting channel to the left of the objective lens and a left-right deflecting channel located below the lens. Gallbladder fundic retraction was performed with the aid of one laparoscopic grasper.

RESULTS

Cholecystectomy was successful in all survival animals. Median procedure time was 81 minutes (range 31-163 minutes), with a decrease over time. Visualization of all structures was achieved, and clipping of the cystic duct and artery was successful in all cases. Dissection of the gallbladder via the left-right channel was enhanced with retraction via the up-down deflecting channel. Nine of 10 animals survived without complications. One animal died, on postoperative day 2, secondary to peritonitis due to a leak from the gastrotomy site.

CONCLUSIONS

This endoscope, with deflecting working channels, allows transgastric cholecystectomy in pigs. The endoscope was stable enough to be used without an overtube and facilitated retraction and dissection. This endoscope is promising for use in transgastric cholecystectomy in human beings.

Colonic sterilization for natural orifice translumenal endoscopic surgery (NOTES) procedures: a comparison of two decontamination protocols

BACKGROUND

This study aimed to evaluate the effect of two different sterilization protocols on the bacterial counts in the swine colon as preparation for natural orifice translumenal endoscopic surgery (NOTES) surgery.

METHODS

In this study, 16 swine were randomized to two different colonic sterilization protocols: low colonic irrigation using 300 ml of a 1:1 dilution of 10% povidone-iodine (Betadine) with sterile saline, followed by 1 g of cefoxitin dissolved in 300 ml of saline or two consecutive 300-ml irrigations using a quaternary ammonium antimicrobial agent (Onamer M). Colonic cultures were taken before colonic cleansing after a decontamination protocol and after completion of the NOTES procedure. The Invitrogen live/dead bacterial viability kit was used to assess for change in the bacterial load. A qualitative culture of peritoneal fluid was obtained at the end of the NOTES procedure. Colon mucosal biopsies obtained immediately after the sterilization procedure and at the 2-week necropsy point were evaluated for mucosal changes.

RESULTS

Protocol 1 resulted in an average 93% decrease in live colonic bacteria versus 90% with protocol 2 (nonsignificant difference). After a NOTES procedure, group 1 had a 62% increase in live bacteria and group 2 had a 31% increase (nonsignificant difference). Peritoneal cultures also were obtained. Bacteria were isolated from the peritoneal fluid of all the animals, and two or more species were isolated from 75% of the animals. There was no evidence of peritoneal infection at necropsy. Reactive epithelial changes and mild inflammation were the only pathologic abnormalities. No changes were noted at histologic evaluation of colonic mucosa after 2 weeks, demonstrating that these were temporary changes.

CONCLUSION

Colonic irrigation with Betadine and antibiotics are as effective for bacterial decontamination of the swine colon as a quaternary ammonium compound. The results of this study support the use of either protocol. Despite thorough decontamination, peritoneal contamination occurs. The significance of this for humans is unknown.

Gastrotomy creation and closure for NOTES using a gastropexy technique (with video)

BACKGROUND

Safe and efficient gastrotomy creation and closure is pivotal for natural orifice transluminal endoscopic surgery (NOTES).

OBJECTIVE

To test a method of transgastric access and closure with commercially available devices.

DESIGN

An animal survival study.

SETTING

University hospital.

PATIENTS

Fifteen pigs.

INTERVENTIONS

By using a surgical suture passer, under endoscopic guidance, 3 percutaneous stay sutures were placed, in a triangular fashion, through the gastric wall. A gastrotomy was created with a dilation balloon, which was introduced over a guidewire through the gastric wall in the center of the 3 sutures. After performing a NOTES procedure, the gastrotomy was closed by tying the sutures. Necropsies were performed after 2 to 4 weeks.

MAIN OUTCOME MEASUREMENTS

Success and time of gastrotomy creation and closure, and intraoperative and postoperative complications.

RESULTS

Gastrotomies were successfully created and closed in all the animals. The median time to create a gastrotomy was 19 minutes (range 11-85 minutes), and the median closure time was 1 minute (range 1-45 minutes). One pig died on postoperative day 1 because of peritonitis caused by a leaking gastrotomy site that extended beyond the stay sutures. There were no other gastrotomy-related complications. All gastrotomies were well healed at the necropsy.

LIMITATION

No control group.

CONCLUSIONS

We evaluated a simple method by using the principles of the PEG technique combined with a gastropexy, which is familiar to the majority of endoscopists. Strict attention to the gastrotomy site is needed, because one leak was from the gastrotomy site that extended beyond the stay sutures.

Evaluation of a novel endoluminal stapling procedure to restrict the lower esophageal sphincter and reduce reflux

BACKGROUND AND STUDY AIMS

An effective, safe, and long-lasting endoluminal treatment for gastroesophageal reflux disease (GERD) would be an attractive prospect. We developed an endoluminal technique to restrict and tighten the lower esophageal sphincter (LES), by using a transoral endoscopic stapling device in a porcine model.

PATIENTS AND METHODS

Pre-interventional evaluation comprised endoscopy, manometry, and 48-hour pH measurement of the distal esophagus using the catheterless BRAVO pH capsule. By placing the endoluminal stapling device at the LES and firing a 2.5-cm staple line, a vertical plication was created. In five pilot pigs (phase 1), plications were placed in various locations at the LES. In another five pigs (phase 2), plications were placed uniformly at the mid level of the LES on the lesser curvature side. Measurements were repeated 2 weeks after the procedure. Necropsy and histological analysis were performed.

RESULTS

Endoluminal stapling was successfully completed in all animals. In phase 2, the median procedure time was 15 minutes (range 10-55 minutes). LES pressure increased from 10.5 mmHg (+/- 2.5 mmHg) to 14.3 mmHg (+/- 3.8 mmHg) (P = 0.038). Median percentage of time with pH below 4 decreased from 6.6% (range 2.9%-48.8%) to 2.2% (range 0%-10.4%) (P = 0.043). Histology showed the staple line involving the muscular layer in all pigs. A gap was present in the central part of the staple line in three pigs resulting in a mucosa-muscular bridge of tissue. This bridge did not influence the results.

CONCLUSION

This novel endoluminal technique is feasible and safe in a porcine model over 2 weeks. It is appealing due to its simplicity and ease of application. Further studies aimed at eliminating the gap in the staple line and investigating more animals over longer survival periods are needed.

Endoscopic colotomy closure after full thickness excision: comparison of T fastener with multiclip applier

BACKGROUND AND STUDY AIMS

Safe, reliable, and efficient endoscopic closure of a colotomy is paramount for endoscopic full thickness excision of the colon. Two newly developed devices, the Tissue Apposition System (TAS) and the InScope Multi-Clip Applier (IMCA), may help to achieve this. The aim of this study was to determine the feasibility of using each device to close colotomies after full thickness wall excisions.

MATERIAL AND METHODS

12 pigs were used in the study. After laparoscopic full thickness excision of the colonic wall, the defect was closed using either the TAS or the IMCA. Closure was performed under laparoscopic vision. Success of colotomy closure, time taken for colotomy closure, postoperative infections, and complication rates were recorded.

RESULTS

Complete closure was achieved in 6/6 pigs in the TAS group. In 5/6 pigs in the IMCA group closure was successful; in one pig laparoscopic assistance was used. Median closure time (range) was significantly lower in the TAS group at 48 minutes (15 - 51) vs. 76 minutes (43 - 145) in the IMCA group. There were no postoperative infections or complications.

CONCLUSIONS

Endoscopic closure after full thickness colonic wall excision is feasible with both the TAS and the IMCA. Closure times are significantly shorter and handling is easier with the TAS. Combined use of both systems might be beneficial.