Outcomes of second self-expandable metallic stent insertion for malignant gastric outlet obstruction

Background

Self-expandable metallic stents are used widely to relieve malignant gastric outlet obstruction (GOO). However, restenosis or migration of first stents is a frequent complication. The purpose of this retrospective cohort study was to evaluate the effectiveness of second stents as an approach to manage failure of first stents in patients with malignant GOO.

Methods

A total of 222 patients with gastric cancer received first stents due to inoperable GOO at National Cancer Center in Korea between January 2008 and June 2011. Monthly follow-up interviews were performed, and second stents (stent-in-stent or stent-after-migration) were inserted in 59 patients by June 2012. Technical and clinical successes and long-term complications were evaluated.

Results

The technical and immediate clinical success rates were 98.3 % (58/59) and 91.5 % (54/59), respectively. Patients who received a second stent due to late complications involving the first stent (migration, restenosis, and fracture) showed a higher clinical success rate (95.8 % [46/48]) than patients who received a second stent due to immediate clinical failure of the first stent (72.7 % [8/11], p = 0.04). The immediate clinical success rate of stent-after-migration (100 % [11/11]) was not different from that of stent-in-stent (89.6 % [43/48], p = 1.0). The stent dysfunction rate of stent-after-migration (27.3 % [3/11]) also was similar to that of stent-in-stent (29.2 % [14/48], p = 1.0). The median patencies of stent-in-stent and stent-after-migration were 27.4 and 58.4 weeks, respectively (p = 0.177). There were no significant prognostic factors for patency of second stents.

Conclusions

Insertion of a second stent is effective for treating the first-stent failure in gastric cancer patients with GOO, especially if the immediate outcome of the first stent was successful.     

Clinical Outcome and Indications for Palliative Gastrojejunostomy in Unresectable Advanced Gastric Cancer: Multi-Institutional Retrospective Analysis

Background

Palliative gastrojejunostomy (GJJ) for gastric outlet obstruction (GOO) associated with unresectable advanced gastric cancers (UAGC) is the most commonly used treatment modality, but its indication remains controversial. In this multi-institutions study, we investigated the clinical outcome of GJJ for UAGC and predictors of outcome and survival.

Methods

A retrospective analysis was performed on 211 patients who underwent palliative GJJ for GOO caused by UAGC from 29 institutions between 2007 and 2009. Operative outcome including postoperative morbidity, mortality, assessment of oral intake by GOO Scoring System (GOOSS) and survival time were recorded. Prognostic factors for overall survival and risk factors for hospital death were investigated by univariate and multivariate analyses.

Results

Postoperative oral food intake was recorded in 203 (96 %) patients. The average GOOSS improved from 1.1 at baseline to 2.5 at 1 month after surgery and remained above 2 for up to 6 months. Overall morbidity, 30-day mortality and hospital death rates were 22, 6 and 11 %, respectively. Median survival time was 228 days and 1-year survival rate was 31 %. Poor performance status (PS), prior chemotherapy and high C-reactive protein (CRP) level were significant independent predictors of poor survival. Poor PS and high CRP were also identified as significant risk factors of hospital death.

Conclusions

Palliative GJJ is beneficial for GOO caused by UAGC in terms of improvement of oral food intake, with acceptable morbidity and mortality. However, its indication for patients with poor PS, high CRP level, and a history of chemotherapy is less clear.     

Palliation of malignant gastric outlet obstruction with simultaneous endoscopic insertion of afferent and efferent jejunal limb enteral stents in patients with recurrent malignancy

Background

Patients with prior pancreaticobiliary or distal gastric cancer treated surgically may have local anastomotic recurrence with obstruction of the afferent and efferent jejunal limbs. This report describes the efficacy and safety of simultaneous endoscopic insertion of self-expanding metal stents into the afferent and efferent jejunal limbs in patients with gastric outlet obstruction (GOO) of post-surgical anatomy for palliation of recurrent malignancy.

Methods

Patients were identified from an endoscopic database at a specialized cancer center between September 2007 and March 2014. Technical success was defined as single-session insertion of afferent and efferent jejunal limb enteral stents. Clinical success was defined as immediate symptom relief and ability to advance diet. A durable response was defined as symptom relief of at least 60 days or until hospice placement or death.

Results

Twenty-three patients were identified who underwent insertion of two 22-mm-diameter uncovered duodenal stents. Stent length varied from 60 to 120 mm. Stents were placed under endoscopic and fluoroscopic guidance. Three patients required balloon dilation to facilitate stent insertion. Average procedure time was 58.8 min (range 28–120). Technical success was achieved in 23/24 (96 %) patients. Clinical success was achieved in 19/23 (83 %) patients. Following initial stent insertion and prior to subsequent re-intervention, 11/19 (58 %) patients had a durable response with a median duration of 70 days (range 4–315). Eight (42 %) patients underwent subsequent re-intervention at a median of 22 days (range 11–315). Five patients had stent revision and were able to tolerate oral intake. Two patients had percutaneous endoscopic gastrostomy/jejunostomy insertion. One patient required surgical diversion for persistent obstruction. Complications included stent migration and post-stent insertion bacteremia due to food bolus obstruction.

Conclusions

Recurrent malignant GOO in patients with post-surgical anatomy treated with simultaneous endoscopic enteral stenting of afferent and efferent jejunal limbs has a high rate of technical and clinical success and low rate of complications and provides effective palliation.

     

Perioperative inflammatory response in natural orifice translumenal endoscopic surgery

Background

Natural orifice translumenal endoscopic surgery (NOTES) could offer multiple advantages compared with the laparoscopic approach. One such potential advantage, not yet proven, is the inferior inflammatory response, which translates into less significant operative stress. This study aimed to compare the immuno-inflammatory response between transgastric NOTES and laparoscopy for simple surgical procedures (oophorectomy) with reference to the cytokine levels.

Methods

For this study, 20 female pigs were randomly assigned to either NOTES or laparoscopic oophorectomy. Seven animals were used as a control group and received only general anesthesia, with no other procedure performed. Blood samples were obtained before surgery, 1 h after the start of the procedure, and at the end of the intervention. The serum levels of IL1β and IL6 were determined using a porcine enzyme-linked immunosorbent assay (ELISA) kit. The mean operative time, intraoperative incidents, and postoperative complications were recorded. On postoperative day 14, the animals were killed, and gastric leak tests were performed.

Results

Both the NOTES and laparoscopic procedures were successfully completed. No gastric leaks were observed during necropsy. The transgastric oophorectomy required a significantly longer time to perform than the laparoscopic surgery. Compared with the NOTES procedures, laparoscopic oophorectomy resulted in significantly higher levels of interleukin-1β (IL1β) (42.34 ± 5.26 ng/ml with NOTES vs 46.93 ± 4.79 ng/ml with laparoscopy; p = 0.028) and IL6 (66.95 ± 7.29 ng/ml with NOTES vs 71.75 ± 4.76 ng/ml with laparoscopy, p = 0.049) during the postoperative phase. No statistical difference was detected between the pre- and postoperative cytokine levels in the NOTES group.

Conclusion

The study findings suggest that pure transgastric endoscopic surgery is a safe approach resulting in less perioperative inflammatory response than laparoscopy in the early postoperative phase.     

Pure transvesical NOTES appendectomy using a 5-mm rigid laparoscope: a feasibility and survival study with porcine models

Background

Previously, the authors demonstrated the feasibility of a pure transvesical natural orifice translumenal endoscopic surgery (NOTES) for uterine horn resection (UHR) using a rigid ureteroscope in swine as an appendectomy model. However, visualization was poor, and there was room for improvement. The authors have assessed the feasibility and safety of a revised technique that uses a 5-mm rigid laparoscope.

Methods

Eight operations on four female pigs (35–40 kg) were performed as a proof of concept study. Four right-side operations were performed in a survival model. The surgical procedure was similar to the original technique. However, the rigid ureteroscope was replaced by a 5-mm laparoscope after modification of the access system. In addition, the clipped metal threads used for bladder closure were easily placed with a long 13-gauge needle. In the survival model, a Foley catheter was placed for 1 day.

Results

The new technique provided considerably better visualization and operability than the original technique. The mean total operative time was 96.6 ± 18.2 min, and the mean estimated blood loss was 15.0 ± 13.5 ml. On postoperative day 3, pig 2 in the survival study died of peritonitis resulting from a small bowel injury. The lab results for the other pigs demonstrated no adverse events and tolerable immune responses. Necropsy showed complete healing of the vesicotomy.

Conclusions

The revised transvesical NOTES UHR technique improved the outcomes and feasibility of the original technique. This approach may be translatable to human appendectomy procedures in the future.     

Transgastric placement of biologic mesh to the anterior abdominal wall

Background

Incisional hernia repairs have a risk of wound complications that may be decreased using a natural orifice transluminal endoscopic surgery (NOTES) approach. The aim of this study was to determine the feasibility and safety of transgastric mesh placement to the anterior abdominal wall in a porcine model as a precursor to future studies of NOTES ventral hernia repair.

Methods

The procedure was done under sterile conditions with a double lumen endoscope using a plastic overtube. The endoscope was placed in the stomach preloaded with an overtube. Entrance of the endoscope and overtube into the peritoneal cavity was performed with the percutaneous endoscopic gastrostomy (PEG) technique. A 13 × 15 cm Surgisis^® Gold? mesh with four corner sutures was delivered through the overtube. Transfascial suture passer and endoscopic grasper were used to externalize the sutures and attach the mesh to the anterior abdominal wall. The gastrotomy was closed with a transabdominal gastropexy. The pigs were sacrificed at 2 weeks.

Results

Mesh placement was performed in five pigs. Operative time was 215 min (standard deviation, SD 99 min). The most difficult portion of the procedure involved manipulating the gastric overtube, likely exposing the mesh to bacteria in the stomach. Culture-positive abscesses were present at the mesh in 3/5 animals. The mesh appeared intact in 4/5 animals; one of the infected meshes had delamination of 50% of the mesh. Adhesions to the mesh surface varied from 2% to 100%. At 2 weeks, median mesh size was 116 cm² (range 96–166 cm²) and median contraction was 41% (range 15–51%). Histologic evaluations demonstrated marked inflammation and fibrosis progressing into the mesh material.

Conclusions

Totally endoscopic transgastric delivery and fixation of a biologic mesh to the anterior abdominal wall is feasible. Challenges remain in designing systems for mesh delivery that exclude gastric content. Once these problems can be surmounted NOTES ventral hernia repair may become an option in man.     

Metallic Stent Placement in Patients with Recurrent Malignant Obstruction in the Surgically Altered Stomach

Purpose

The purpose of this study was to assess the technical feasibility and clinical effectiveness of expandable metallic stent placement in 196 patients with recurrent malignant obstruction in their surgically altered stomach.

Methods

The 196 patients were treated using five different types of gastric surgery performed for gastric cancer: total gastrectomy (type 1) in 73 patients; distal gastrectomy with gastroduodenostomy (type 2) in 39 patients; distal gastrectomy with a Roux-en-Y gastrojejunostomy (type 3) in 21 patients; distal gastrectomy with a gastrojejunostomy (type 4) in 49 patients; and palliative gastrojejunostomy for unresectable gastric cancer (type 5) in 14 patients. The technical and clinical success rates, complications, dysphagia score, and influence of chemotherapy were evaluated and the complications compared between the two stent types. The overall survival and stent patency were calculated using the Kaplan–Meier method.

Results

Stent placement was technically successful in 192 of 196 patients (97.9 %), with 184 of the 192 patients (95.8 %) showing symptomatic improvement. The mean dysphagia score improved from 3.24 ± 0.64 to 1.48 ± 0.82 (p < 0.001). The complication rate was 25 %. The incidence of stent migration was significantly higher in fully covered stents and in patients who underwent chemotherapy (p < 0.001 and p = 0.005, respectively). Chemotherapy was significantly associated with an increase of survival (p < 0.001). The median survival and stent patency were 131 and 90 days, respectively.

Conclusion

Placement of expandable metallic stents in patients with recurrent cancer after a surgically altered stomach is technically feasible and clinically effective. Chemotherapy was associated with increased stent migration and prolonged survival.     

Transrectal robotic natural orifice translumenal endoscopic surgery (NOTES) applied to intestinal anastomosis in a porcine intestine model

Background

Natural orifice translumenal endoscopic surgery (NOTES) is a minimally invasive operation using devices such as flexible endoscopes and linear or circular staplers. Nevertheless, hand-sewn anastomosis in NOTES remains challenging. This study aimed to investigate the feasibility of transrectal robotic NOTES requiring intracorporeal small intestinal anastomosis and closure of the rectal anterior wall incision in a relevant human model.

Methods

The authors developed a flexible rectal proctoscope with a diameter of 43 mm for transrectal robotic NOTES. Small intestinal anastomosis was performed in a porcine intestinal transrectal NOTES model using two robotic arms and a camera inserted through the proctoscope and a rectal anterior wall incision. The quality of transrectal small intestinal anastomosis using the da Vinci surgical system (transrectal robotic NOTES group) was compared with that of transabdominal anastomosis using the da Vinci surgical system (transabdominal robot-assisted surgery group) and transrectal anastomosis using traditional transanal endoscopic microsurgery (TEM) instruments (TEM NOTES group). The quality of transrectal rectal anterior wall suturing in the transrectal robotic NOTES group was compared with that of the TEM NOTES group and the open surgical instruments group (open group).

Results

Robotic intracorporeal suturing was performed successfully in the porcine intestine model. During small intestinal anastomosis, burst pressure in the transrectal robotic NOTES group (67.7 ± 29.3 mmHg) was similar to that in the transabdominal robot-assisted surgery group (73.3 ± 18.2 mmHg) but significantly higher than in the TEM NOTES group (20.3 ± 24.0 mmHg; p < 0.01). During rectal anterior wall suturing, the burst pressure did not differ significantly between the transrectal robotic NOTES group (149.9 ± 81.1 mmHg) and the open group (195.0 ± 60.5 mmHg).

Conclusions

The preliminary safety and efficacy of transrectal robotic NOTES was established. Further studies are required to determine the practical feasibility of this procedure.     

Treating sleeve gastrectomy leak with endoscopic stenting: the kuwaiti experience and review of recent literature

Background

Obesity today is a leading cause of global morbidity and mortality, and bariatric surgeries such as laparoscopic sleeve gastrectomy (LSG) are increasingly playing a key role in its management. Such operations, however, carry many difficult and sometimes fatal complications, including leaks. This study aims at evaluating the effectiveness of endoscopic stenting in treating gastric leaks post-LSG.

Methods

A retrospective study was conducted to the patients who were admitted with post-LSG gastric leak at Al-Amiri Hospital Kuwait from October 2008 to December 2012 and were subsequently treated with stenting. The patients were stented endoscopically with self-expandable metal stent (SEMS), and a self-expandable plastic stent (SEPS) was used to facilitate stent removal.

Results

A total of 17 patients with post-LSG leaks underwent endoscopic stenting. The median age was 34 years (range 19–56), 53 % of the patients were male, and mean body mass index (BMI) was 43 kg/m ² . The median duration of SEMS placement per patient was 42 days (range 28–84). The SEPS-assisted retrieval process took a median duration of 11 days (range 14–35). Successful treatment of gastric leak was evident in 13 (76 %) patients, as evident by gastrografin swallow 1 week after stent removal. In addition, a shorter duration between the LSG and the time of stent placement was associated with a higher success rate of leak seal.

Conclusions

The use of SEMS appears to be a safe and effective method in the treatment of post-LSG leaks, with a success rate of 76 %. The time frame of intervention after surgery is critical, as earlier stent placement is associated with favorable outcomes. Finally, SEPS is often required to facilitate SEMS removal, and further modification of stents and its delivery system may improve results.     

Laparoscopic gastrojejunostomy for the treatment of gastric outlet obstruction

Background and Objectives:

Laparoscopic gastrojejunostomy (LGJ) has been proposed as the technique preferred over open gastrojejunostomy for relieving gastric outlet obstruction (GOO) due to malignant and benign disease. This study investigates the feasibility and safety of LGJ for GOO.

Methods:

A retrospective review was performed of patients who underwent LGJ at Mount Sinai Medical Center from 2004 to 2008. Patient''s operative course and long-term outcomes were collected.

Results:

Twenty-eight patients were reviewed (16 had malignancy, 7 had PUD, 3 had Crohn''s disease, and one had obstruction of unclear cause). Average operative time was 170 minutes, and estimated blood loss was 80cc. One case was converted to open; another had stapler misfiring. Patients regained bowel function at a median of 3 days and remained in the hospital for a median of 8 days. There were 4 major postoperative complications (14%): 1 anastomotic leak and 1 trocar-site hemorrhage requiring reoperation and 2 gastrointestinal bleeds requiring endoscopic intervention. There were 5 minor complications (18%), including a partial small bowel obstruction, 1 patient developed bacteremia, and 3 patients had delayed gastric emptying. One patient had persistent GOO requiring reoperation 3 months later.

Conclusion:

LGJ can be performed for GOO with improved outcome and an acceptable complication rate compared to the open GJ reported in the literature.     

Enteral stenting versus gastrojejunostomy for palliation of malignant gastric outlet obstruction

Background and aims

Endoscopic placement of enteral self-expandable metallic stents is an alternative to surgical gastrojejunostomy (GJ) for palliation of malignant gastric outlet obstruction (GOO). Factors associated with clinical outcomes are not known. The aims of this study are to compare the overall complication rate and effectiveness (duration of oral intake) between endoscopic stenting (ES) and GJ in patients with GOO and identify predictors of clinical outcomes.

Patients and methods

This was a retrospective cohort study at a single tertiary academic center. Patients who underwent ES or GJ for treatment of GOO between 1/2001 and 12/2010 were identified using an institutional claims database. The electronic medical records for each patient were reviewed. Univariate and multivariate logistic regression analyses were performed to study the association of treatment outcomes with patient factors and cancer therapy.

Results

120 patients had ES while 227 had GJ. Technical success was higher for GJ (99 vs. 96 %, p = 0.004). Complication rates were higher in the GJ group (22.10 vs. 11.66 %, p = 0.02). Reintervention was more common with ES [adjusted odds ratio (OR) 9.18, p < 0.0001]. Mean length of hospital stay (LOHS) was shorter (adjusted p = 0.005) in the ES compared with the GJ group. However, mean hospital charges, including reinterventions, were greater in the ES group (US $34,250 vs. US $27,599, p = 0.03). ES and GJ had comparable reintervention-free time in patients who had reintervention (88 vs. 106 days, respectively, p = 0.79). Chemotherapy [adjusted hazard ratio (HR) 3 > 0.57, p = 0.04] and radiation therapy (adjusted HR 0.35, p = 0.03) were associated with significantly longer duration of oral intake after ES or GJ.

Conclusion

ES is associated with fewer complications, shorter LOHS, but higher reintervention rates and overall charges.     

Initial Experience of Single-Port Surgery Assisted by Percutaneous Instruments for Gastric Bypass: a Combination of Safety and Minimally Invasive Surgery

Background

We present here the first reported cases of patients undergoing gastric bypass with a hybrid technique that involves a new concept of percutaneous instruments and provides the advantages of minimally invasive single-port surgery while maintaining the triangulation, safety, and timing of operative procedures.

Methods

This was a prospective pilot study of eight patients selected for gastric bypass between December 2011 and January 2012 and treated by a technique that combined single SSL port and percutaneous surgical set PPS. We performed hand-sewn gastrojejunostomy in all cases. We analyzed preliminary results at 1 month and focused on the feasibility of the technique, duration of surgery, perioperative complications, and cosmetic results. The Ethics Committee of our institution approved this study and we obtained the informed consent of each patient.

Results

We completed the procedure successfully in all patients. No conversions to laparotomy or classic laparoscopy were required. The average time of surgery was 112 min (85–155). Length of hospital stay was 4 days (3–5). One patient was re-admitted on the seventh postoperative day for gastrointestinal bleeding from the gastrojejunostomy suture and treated by endoscopic clipping. Residual scars were less than 2 cm for the single midline port and 2 mm for the percutaneous instruments.

Conclusions

This new technique combines the advantages of single-port surgery with the safety of conventional laparoscopy by using percutaneous instruments and leaves minimal scarring. It is likely that the use of percutaneous instrumentation will become widespread in all areas of laparoscopic surgery.     

Transumbilical thoracic sympathectomy with an ultrathin flexible endoscope in a series of 38 patients

Background

The newest trend in the field of thoracic surgery, thoracic natural orifice transluminal endoscopic surgery (NOTES), is still in the early stages of development and limited to animal experiments. Transumbilical endoscopic surgery could work as a viable intermediate step before pure NOTES. We describe our experiences performing transumbilical–diaphragmatic thoracic sympathectomy with an ultrathin flexible endoscope for palmar and axillary hyperhidrosis in human patients.

Methods

From April 2010 to January 2012, a total of 38 patients underwent transumbilical–diaphragmatic thoracic sympathectomy. Through the incision in the umbilicus, a newly developed long trocar was inserted into the abdominal cavity. An ultrathin endoscope was introduced through the long trocar and then passed through the rigid incision made in the left and right diaphragm and into the thoracic cavity. The ganglion was ablated at the desired thoracic level.

Results

Sympathectomy was performed successfully in all patients. Mean operation time was 68 ± 16 (range, 48–107) minutes. There was no mortality and no conversion to open surgery during the operation of any patient. At a median follow-up of 11 (range, 4–12) months after surgery, no diaphragmatic hernia was observed. The rate of palmar hyperhidrosis and axillary hyperhidrosis resolution was 100 and 75 %, respectively.

Conclusions

Transumbilical endoscopic thoracic sympathectomy is technically feasible and safe, which has the possible advantages of pure NOTES and can be performed in routine clinical practice.     

Gastric Leak After Laparoscopic Sleeve Gastrectomy: Early Covered Self-Expandable Stent Reduces Healing Time

Background

Laparoscopic sleeve gastrectomy has become a very frequent procedure in bariatric surgery due to its efficacy and simplicity compared to gastric bypass. Gastric staple line leak (1 to 7 % of cases) is a severe complication with a long nonstandardized treatment. The aim of this retrospective study was to examine the success and tolerance of covered stents in its management.

Methods

From January 2009 to December 2011, nine patients with gastric staple line leaks after sleeve gastrectomy were treated with covered stents in our department (seven referred from other institutions). The leaks were diagnosed by CT scan and visualized during the endoscopy. Among the studied variables were operative technique, post-operative fistula diagnosis delay, stent treatment delay, and stent tolerance. In our institution, Hanarostent® (length 17 cm, diameter 18 mm; M.I. Tech, Seoul, Korea) was used and inserted under direct endoscopic control.

Results

Stent treatment was successful in seven cases (78 %). Two other cases had total gastrectomy (405 and 185 days after leak diagnosis). Early stent removal (due to migration or poor tolerance) was necessary in three cases. The average stent treatment duration was of 6.4 weeks, and the average healing time was 141 days. The five patients with an early stent treatment (≤3 weeks after leak diagnosis) had an average healing time of 99 days versus 224 for the four others.

Conclusions

Covered self-expandable stent is an effective treatment of gastric leaks after sleeve gastrectomy. Early stent treatment seems to be associated with shorter healing time.     

Clinical outcomes of re-stenting in patients with stent malfunction in malignant gastric outlet obstruction

Background and aims

Self-expanding metal stents (SEMS) have been used for the palliative treatment of malignant gastric outlet obstruction (GOO). The aim of this study was to evaluate the clinical outcomes of salvage SEMS for stent malfunction and to identify the prognostic factors for a longer patency.

Methods

A total of 108 patients who underwent a secondary salvage SEMS placement for a primary stent malfunction were retrospectively reviewed at the Seoul National University Hospital between August 2004 and May 2013. The duration of patency for salvage SEMS was defined as the time between salvage SEMS placement and the recurrence of obstructive symptoms that were confirmed either endoscopically or radiologically.

Results

The technical and clinical success rates for salvage SEMS were 100 and 82.4 % (95 % confidence interval [CI] 74.0–89.0), respectively. A salvage SEMS malfunction occurred in 29 (26.9 %) of the 108 patients. The median duration of patency for salvage SEMS was 59.5 days (range 3–928, 95 % CI 73.7–118.3). Longer SEMS patencies of more than 60 days were significantly associated with palliative chemotherapy (odds ratio = 2.539, 95 % CI 1.031–6.252, p = .043). For salvage SEMS, covered–uncovered stents had a longer patency duration, as compared with other combinations of primary and salvage stent types.

Conclusions

Longer patency durations for salvage SEMS were associated with palliative chemotherapy after salvage SEMS insertion. Salvage SEMS could be a feasible and effective treatment for primary stent malfunction in malignant GOO.

     

Needs analysis for developing a virtual-reality NOTES simulator

Introduction and study aim

Natural orifice translumenal endoscopic surgery (NOTES) is an emerging surgical technique that requires a cautious adoption approach to ensure patient safety. High-fidelity virtual-reality-based simulators allow development of new surgical procedures and tools and train medical personnel without risk to human patients. As part of a project funded by the National Institutes of Health, we are developing the virtual transluminal endoscopic surgery trainer (VTEST?) for this purpose. The objective of this study is to conduct a structured needs analysis to identify the design parameters for such a virtual-reality-based simulator for NOTES.

Methods

A 30-point questionnaire was distributed at the 2011 National Orifice Surgery Consortium for Assessment and Research meeting to obtain responses from experts. Ordinal logistic regression and the Wilcoxon rank-sum test were used for analysis.

Results

A total of 22 NOTES experts participated in the study. Cholecystectomy (CE, 68 %) followed by appendectomy (AE, 63 %) (CE vs AE, p = 0.0521) was selected as the first choice for simulation. Flexible (FL, 47 %) and hybrid (HY, 47 %) approaches were equally favorable compared with rigid (RI, 6 %) with p < 0.001 for both FL versus RI and HY versus RI. The transvaginal approach was preferred 3 to 1 to the transgastric. Most participants preferred two-channel (2C) scopes (65 %) compared with single (1C) or three (3C) or more channels with p < 0.001 for both 2C versus 1C and 2C versus 3C. The importance of force feedback and the utility of a virtual NOTES simulator in training and testing new tools for NOTES were rated very high by the participants.

Conclusion

Our study reinforces the importance of developing a virtual NOTES simulator and clearly presents expert preferences. The results of this analysis will direct our initial development of the VTEST? platform.     

Transvaginal cholecystectomy without laparoscopic support using prototype flexible endoscopic instruments in a porcine model

Background

Transvaginal cholecystectomy with laparoscopic assistance has been performed safely in humans. The next goal was to develop a natural orifice transluminal endoscopic surgery (NOTES) technique to perform cholecystectomy without laparoscopic instruments using one flexible endoscope and flexible accessories. The aim of the study was to test the feasibility of the procedure in a survival porcine model.

Methods

Cholecystectomies were attempted in five 88–130-lb. pigs with a planned 2-week survival. Prototype flexible instruments (NOTES Toolbox, Ethicon Endo-Surgery, Inc.) were used to aid in access, dissection, and removal of the gallbladder via the transvaginal route.

Results

Cholecystectomy could be completed without abdominal incision using prototype instruments in four out of five pigs. The cystic duct could be exposed with a flexible hook knife and clips applied. The steerable trocar improved stability and the precision of the dissection. The critical view was established in all five pigs. Dissection of the gallbladder off the liver bed was imprecise resulting in gallbladder perforation in all pigs and liver hemorrhage in two. At necropsy, all clips on the cystic duct were secure and no bile leak, bowel injury, or adhesions were present.

Conclusions

NOTES cholecystectomy without laparoscopic support is feasible but challenging using prototype flexible endoscopic devices. A prototype clip applier was effective in controlling the cystic duct. Further improvements in instrument design to ensure precision and safety are needed before flexible devices should be used for pure NOTES procedures in humans.     

Educational and training aspects of new surgical techniques: experience with the endoscopic–laparoscopic interdisciplinary training entity (ELITE) model in training for a natural orifice translumenal endoscopic surgery (NOTES) approach to appendectomy

Background

Natural orifice translumenal endoscopic surgery (NOTES) is a new surgical concept that requires training before it is introduced into clinical practice. The endoscopic–laparoscopic interdisciplinary training entity (ELITE) is a training model for NOTES interventions. The latest research has concentrated on new materials for organs with realistic optical and haptic characteristics and the possibility of high-frequency dissection. This study aimed to assess both the ELITE model in a surgical training course and the construct validity of a newly developed NOTES appendectomy scenario.

Methods

The 70 attendees of the 2010 Practical Course for Visceral Surgery (Warnemuende, Germany) took part in the study and performed a NOTES appendectomy via a transsigmoidal access. The primary end point was the total time required for the appendectomy, including retrieval of the appendix. Subjective evaluation of the model was performed using a questionnaire. Subgroups were analyzed according to laparoscopic and endoscopic experience.

Results

The participants with endoscopic or laparoscopic experience completed the task significantly faster than the inexperienced participants (p = 0.009 and 0.019, respectively). Endoscopic experience was the strongest influencing factor, whereas laparoscopic experience had limited impact on the participants with previous endoscopic experience. As shown by the findings, 87.3% of the participants stated that the ELITE model was suitable for the NOTES training scenario, and 88.7% found the newly developed model anatomically realistic.

Conclusions

This study was able to establish face and construct validity for the ELITE model with a large group of surgeons. The ELITE model seems to be well suited for the training of NOTES as a new surgical technique in an established gastrointestinal surgery skills course.     

Intramural acellular porcine dermal matrix (APDM)-assisted gastrotomy closure for natural orifice transluminal endoscopic surgery (NOTES)

Background

A highly reliable and safe means of gastric closure for natural orifice transluminal endoscopic surgery (NOTES) has yet to be developed. The authors have previously described the self-approximating transluminal access technique (STAT) as a means for gastrotomy closure in transgastric surgery. It has yet to be determined whether biologic mesh can be utilized in facilitating gastrotomy closure via STAT. The aim of this study was to determine the feasibility of implanting an acellular porcine dermal matrix (LifeCell) into the STAT tunnel and investigate whether it will become incorporated into the submucosal plane of the STAT tunnel.

Methods

Five pigs underwent transgastric left uterine horn resection utilizing STAT. For closure, the acellular porcine dermal matrix was implanted within the submucosal plane, occluding the seromuscular incision. The mucosal incision was then closed over the matrix with endoscopically placed clips. Necropsy was performed after a 3 week survival period. Histopathological evaluation of the tunnel and matrix was performed.

Results

The matrix was successfully implanted in all five animals. Average OR time was 151 ± 68 min. Average time to anchor and embed the matrix within the tunnel was 4 ± 1 and 9 ± 12 min, respectively. There was one duodenal perforation related to a balloon occlusion device. Postoperative course was unremarkable; the average weight gain at 3 weeks was 22 ± 5 lbs. On necropsy, one animal had some protrusion of the matrix at the serotomy, with adhesions to small bowel and liver. Histopathology revealed one clinically insignificant microabscess but otherwise demonstrated local inflammation and fibrovascular ingrowth into the matrix.

Conclusions

The porcine dermal matrix can be successfully implanted within the gastric submucosal plane and evidence of incorporation into the gastric wall by 3 weeks was demonstrated.     

Stenting versus gastrojejunostomy for management of malignant gastric outlet obstruction: comparison of clinical outcomes and costs

Background

Although endoscopic stenting is increasingly performed, surgical gastrojejunostomy (GJ) is still considered the gold standard for relief of malignant gastric outlet obstruction (GOO). The aim of this study is to compare clinical outcomes and hospital costs between patients undergoing GJ or stenting for management of malignant GOO.

Methods

A retrospective claims analysis of the Medicare (MedPAR) database was conducted to identify all inpatient hospitalizations for GJ or endoscopic stenting for malignant GOO during 2007–2008. The main outcome measure evaluated using the MedPAR database was a comparison of the total length of hospital stay (LOS) and costs associated with both techniques. As MedPAR is a claims database that does not provide outcomes at patient level, a single-institution retrospective study was conducted to compare the rates of technical and treatment success, post-procedure LOS, and delayed complications per patient between the two techniques.

Results

The MedPAR claims data evaluated 425 stenting and 339 GJ hospitalizations. Compared with GJ, median LOS (8 vs. 16?days; p?<?0.0001) and median cost (US $15,366 vs. US $27,391; p?<?0.0001) per claim were both significantly lower for stenting. Stenting was more commonly performed at urban versus rural hospitals (89 % vs. 11?%; p?<?0.0001), teaching versus non-teaching hospitals (59?% vs. 41?%, p?=?0.0005), and academic institutions (56?% vs. 44?%; p?=?0.0157). The institutional patient data analysis included 29 patients who underwent stenting and 75 who underwent surgical GJ. While both modalities were technically successful and relieved gastric outlet obstruction in all cases, compared with surgical GJ, the median post-procedure LOS was significantly lower for enteral stenting (1.5 vs. 10.7?days, p?<?0.0001). There was no difference in rates of delayed complications between stenting and surgical GJ (13.8 % vs. 6.7?%; p?=?0.26).

Conclusions

While the technical and clinical outcomes of surgical GJ and endoscopic stenting appear comparable, stent placement is less costly and is associated with shorter length of hospital stay. Dissemination of endoscopic stenting beyond teaching, academic hospitals located in urban areas as a treatment for malignant GOO is important given its implications for patient care and resource utilization.