Christina P. Williams

Complete endoscopic closure of gastrotomy after natural orifice translumenal endoscopic surgery using the NDO Plicator.

BackgroundThe NDO Plicator is a device developed for endoscopic treatment of gastroesophageal reflux disease (GERD) by approximation of tissues together with a double-pledgeted U-stitch. It was theorized that this device may facilitate transgastric natural orifice translumenal endoscopic surgery (NOTES) because closure of the transgastric defect remains a key component for advancement of this new technology.MethodsA standardized 12-mm gastrotomy was created endoscopically in four pigs using a combination of needle-knife cautery and balloon dilation. As the endoscope was removed, a Savary soft-tipped wire was introduced into the stomach, and the NDO Plicator was subsequently advanced over the wire. Each defect was identified, and the device was positioned. If necessary, the Plicator’s tissue grasper was used to hold the superior aspect of the gastrotomy and bring the opposed borders of the defect within the jaws of the device. The device was fired three times, leaving three pledgeted suture bundles to close the gastric defect. After closure, each animal was explored, and the integrity of the closure was assessed. The animals underwent in vivo contrast fluoroscopy and ex vivo burst pressure testing studies for assessment of leakage at the closure site.ResultsThe first animal was used to test feasibility, refine techniques, and develop a standard procedure. All of the next three animals studied showed complete sealing of the gastrotomy site without evidence of contrast extravasation on multiplanar fluoroscopic imaging. Each stomach was excised, submerged in water, and subjected to a pressurized air leak test. No leaks were noted until pressures exceeded 55 mmHg.ConclusionThis study supports the use of the NDO Plicator for closure of standardized gastric defects in a porcine model. In addition to closing NOTES gastrotomies, the NDO Plicator may be a particularly useful tool for obtaining complete closure of gastric perforations and anastomotic leaks, and for performing stomal reduction after gastric bypass procedures. The mechanical properties of a closure are not the only factor determining whether a leak will develop. Tissue opposition, ischemia, and tension are important factors that are not easily or reliably measured. The physiologic relevance of gastric bursting pressure is not known. Therefore, corollary animal studies with longer-term evaluation are necessary before research proceeds to clinical trials.

Late phase TNF-alpha depression in natural orifice translumenal endoscopic surgery (NOTES) peritoneoscopy

BACKGROUND Natural orifice translumenal endoscopic surgery (NOTES) allows access to the peritoneal cavity without skin incisions. Contamination of the peritoneal cavity by enteric contents may render NOTES more physiologically and immunologically invasive than previously thought. Measurement of interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) is a validated method to quantify surgical stress. The physiologic and immunologic impact of NOTES is unknown. METHODS A total of 37 swine underwent abdominal exploration via transgastric NOTES peritoneoscopy, laparoscopy (LX), laparotomy (OPEN), or sham surgery (CONTROL) and were allowed to survive. TNF-alpha, IL-1beta, and IL-6 plasma levels were determined at the start and completion of surgery, and at 1 hour, 2 days, and 14 days postoperatively. RESULTS At surgical completion, OPEN animals demonstrated higher TNF-alpha levels than all groups. TNF-alpha levels were similar for all groups at 1 hour and 2 days. NOTES animals had significantly reduced plasma levels of TNF-alpha than all other groups on postoperative days 7 and 14. Controlling for baseline cytokine variability, analysis was repeated using normalized data, which confirmed significantly reduced TNF-alpha levels for NOTES compared with all groups at 14 days. Subset analysis excluding LX and OPEN complications revealed lower NOTES TNF-alpha levels at 7 and 14 days compared with all groups. IL-1beta and IL-6 levels were undetectable in 66.8% and 70.5% of samples, respectively, without significant trends. CONCLUSIONS Diagnostic NOTES peritoneoscopy demonstrated similar levels of systemic proinflammatory cytokine TNF-alpha compared with diagnostic laparoscopy and exploratory laparotomy in the immediate postoperative period despite gross intraperitoneal contamination. None of the surgical groups, however, produced a measurable, consistent trend in IL-1beta or IL-6. Consistently reduced levels of TNF-alpha in NOTES animals in the late postoperative period indicates an immunomodulatory effect of the NOTES surgical technique not present in laparoscopy or laparotomy.

Infectious implications in the porcine model of natural orifice transluminal endoscopic surgery (NOTES) with PEG-tube closure: a quantitative bacteriologic study

BACKGROUND Obtaining reliable closure of transvisceral defects currently limits natural orifice transluminal endoscopic surgery (NOTES). PEG tubes are potential means of managing NOTES gastrotomies. OBJECTIVE To determine the efficacy of PEG closure after NOTES. DESIGN An experimental animal study. SETTING A laboratory. INTERVENTIONS The pigs received gastric lavage with saline solution, chloramphenicol, or no lavage, and then underwent transgastric NOTES peritoneoscopy. Cultures were obtained by endoscopy during the surgery. A sterile foreign body was left in the peritoneal cavity. The gastrotomy was closed with a 20F PEG tube. The animals were observed for 14 days and underwent sterile laparotomy. Cultures of the foreign body and the peritoneal cavity were obtained. MAIN OUTCOME MEASUREMENTS Abscess rate, peritoneal quantitative cultures. RESULTS After 1 exclusion for anesthetic complications, 19 animals underwent NOTES; 18 (94.7%) survived the entire postoperative period. One animal died on postoperative day 2 after the PEG tube dislodged. At 14 days, 5 animals (27.8%) had intra-abdominal abscesses, 8 (44.4%) had positive peritoneal cultures, and 9 (50%) foreign bodies were contaminated on culture. Infectious complications were not altered by the type of gastric lavage or peritoneal bacterial inoculum introduced at the time of surgery. LIMITATION An animal model. CONCLUSIONS PEG closure of a NOTES gastrotomy is associated with subclinical intra-abdominal abscess formation and can result in death when the tube is dislodged during the early postoperative period. Preprocedural gastric lavage does not alter the intra-abdominal bacterial burden introduced at the time of surgery or subsequent infectious outcomes in the porcine model. These concerning findings necessitate additional studies to determine if porcine models are appropriate and applicable to human subjects in the NOTES setting.

Clinical results of intraoperative radiation therapy for patients with locally recurrent and advanced tumors having colorectal involvement.

BACKGROUND Intraoperative radiation therapy (IORT) may be useful in the treatment of patients who have a locally advanced primary and recurrent abdominopelvic neoplasm with colorectal involvement. METHODS A retrospective review of colorectal cancer patients treated since 1999 with IORT using the Mobetron device. RESULTS Forty patients underwent colectomy or proctectomy with IORT. All patients had evidence of local extension to contiguous structures and based on preoperative staging were deemed by the operating surgeon as being likely to have incomplete resection. IORT was selected as an alternative to sacrectomy or exenteration for an expected close margin in 10 patients. Mean survival was 35 +/- 26 months, and 1 patient had local recurrence. CONCLUSIONS The introduction of IORT has allowed a selective treatment approach to locally advanced primary and recurrent neoplasms, which traditionally would have been deemed unresectable. Using IORT, extended resections may be avoided in selected high-risk patients with low risk of local recurrence and minimal morbidity.

Human Peritoneal Membrane Reduces the Formation of Intra-Abdominal Adhesions in Ventral Hernia Repair: Experimental Study in a Chronic Hernia Rat Model

BACKGROUND Adhesions leading to intestinal obstructions and fistulae are severe complications related to the intraperitoneal placement of synthetic meshes. This study evaluated the efficacy of human peritoneal membrane (HPM) in a chronic hernia repair rat model as an anti-adhesive solution for preventing the development of intra-abdominal adhesions. MATERIALS AND METHODS The mechanical properties of HPM and human fascia lata (HFL) were evaluated prior to in vivo implantation. Twenty rats underwent midline laparotomy, which led to the development of chronic hernias 28 d later. Then, animals underwent incisional hernia repair in an underlay fashion (n=5/mesh group) with compressed poly(tetra-fluoro-ethylene) (cPTFE), onto which HPM or HFL were affixed pre-repair, along with two additional controls. The extent and tenacity of intra-abdominal adhesions were determined through qualitative gross evaluations and quantitative tensiometry at 30 d post-repair. The host tissue response was evaluated histologically. RESULTS In hydrated state, the elastic properties of HPM were superior to HFL. Repairs with HPM had significantly less surface area covered by adhesions, with significantly lower tenacity compared with all other groups. Furthermore, intra-abdominal adhesions developed in the presence of HPM were associated with omentum only, and were distributed around the perimeter of the exposed cPTFE. HPM served as an active tissue remodeling template, replacing the traditional foreign body encapsulation with an anatomically and physiologically superior outcome. CONCLUSIONS HPM significantly reduces the extent and tenacity of intra-abdominal adhesion formation, and represents a bioprosthetic template that encourages structural and functional neo peritonealization.

Use of Abdominal Wall Allotransplantation as an Alternative for the Management of End Stage Abdominal Wall Failure in a Porcine Model

BACKGROUND We describe a novel approach for treating end stage abdominal wall failure using isolated abdominal wall allotransplantation in a porcine model. METHODS Full thickness abdominal wall transplants were performed in 13 pairs of genetically mismatched pigs. All recipients received daily immunosuppresion after transplantation. Rejection was assessed by visual inspection and skin biopsies. At the end of the 28 d study period, thickness, stiffness, and tensile strength of the transplanted rectus muscle was measured and compared with native rectus muscle. RESULTS Eight grafts were viable and showed no signs of herniation. Four grafts failed within the first week secondary to vascular thrombosis. One animal had viable graft but was euthanized due to an incarcerated inguinal hernia. Rejection was minimal in six of the eight recipients. At necropsy, the gross thickness of the transplanted muscle flap was reduced compared with the native muscle (4.3 mm versus 7.7 mm, P < 0.001). Histologically, the diameter of the muscle fiber decreased from 0.15 mm to 0.09 mm (P < 0.0001). While the stiffness measurements between the transplanted and native muscles were comparable, the transplanted muscles had significantly lower tensile strength than the native muscles. CONCLUSION This study demonstrates the feasibility of isolated abdominal wall allotransplantation to provide a potential solution for end stage abdominal wall failure. Based on the model set forth, future work will evaluate the biomechanical properties of the composite allograft to provide a suitable dynamic abdominal wall replacement.

Objective analysis of the accuracy and efficacy of a novel fascial closure device.

Abdominal fascial closure after midline laparotomy can be time-consuming and inaccurate and is a common time for needle-stick injuries. The SuturTek 360° Fascial Closure Device (FCD) is designed to provide a secure fascial closure while reducing the risk of needle-stick injury. To date, the accuracy and efficacy of the fascial closure obtained with this device have never been objectively determined. Ten pigs averaging 18 kg were killed and underwent a midline laparotomy. Idealized suture locations were premarked through the fascia. The animals were then randomly assigned to either a traditional suture closure or the FCD for fascial closure. Surgeons were instructed to place sutures through the idealized markers. Surgeons were then evaluated based on the time to close fascia and distance from the markers. Abdominal bursting pressures were obtained using a manometric balloon. Accuracy was also tested on an ex vivo model on which the participants were again asked to place stitches as close as possible to idealized marks, and absolute distance from the idealized location was calculated. The FCD resulted in a faster closure time when compared with traditional closure (5.9 ± 0.6 vs 7.7 ± 1.0 minute, P = .012), with a similar accuracy of placement from the idealized markers (1.5 ± 1.4 mm vs 0.8 ± 1.1 mm). Bursting pressures were similar between the 2 groups: 470 ± 71 mm Hg for FCD versus 453 ± 94 mm Hg for traditional closure ( P = .76). The FCD resulted in a faster fascial closure with similar accuracy and strength when compared with traditional open techniques. The potential reduction in serious needle-stick injuries warrants prospective trials.