Natural-orifice transluminal endoscopic surgery (NOTES) in Europe: summary of the working group reports of the Euro-NOTES meeting 2010.

The fourth Euro-NOTES workshop took place in September 2010 and focused on enabling intensive scientific dialogue and interaction between participants to discuss the state of the practice and development of natural-orifice transluminal endoscopic surgery (NOTES) in Europe. Five working groups were formed, consisting of participants with varying scientific and medical backgrounds. Each group was assigned to an important topic: the correct strategy for dealing with bacterial contamination and related complications, the question of the ideal entry point and secure closure, interdisciplinary collaboration and indications, robotics and platforms, and matters related to training and education. This review summarizes consensus statements of the working groups to give an overview of what has been achieved so far and what might be relevant for research related to NOTES in the near future.

Objective evaluation of the performance of surgical trainees on a porcine model of open colectomy.

BACKGROUND: Evaluation of surgical trainee operative performance is rarely objective. A rating system is proposed that assesses trainee performance objectively and quantifies technical improvement. METHODS: General surgery trainees were evaluated while performing porcine segmental colectomy. Initial instruction was provided for the critical operative steps. Evaluations were later repeated without additional instruction. Performance in 17 critical areas was scored. RESULTS: Twenty-three trainees were evaluated. Performance was divided into thirds, with a significant difference detected between tertiles (P < 0.001). Postgraduate year 2 trainees scored lower than those in years 3 and 4 (P < 0.001), but there was no difference between year 3 and 4 trainees (P = 0.557). Mean repeat scores were improved by 35 per cent, with most improvement at postgraduate year 2 level (71 per cent). Mean time taken to complete the operation was reduced by 23 per cent, with the largest reduction in the year 2 group. CONCLUSION: The results support the use of this rating system as a tool for the objective evaluation of trainee operative skill. Instruction in the performance of segmental colectomy using deconstructed, step-by-step direction improved the ability of junior trainees to complete the operation. This evaluation system may be useful in the assessment, instruction and technical development of surgical trainees.

Facilitating gastrotomy closure during natural-orifice transluminal endoscopic surgery using tissue anchors.

BACKGROUND AND STUDY AIMS: Reliable and secure closure of the gastrotomy after natural-orifice transluminal endoscopic surgery (NOTES) remains a critical step for widespread acceptance and use of this mode of surgery. We describe a novel method for gastrotomy closure using endoscopic tissue anchors. METHODS: A standard upper endoscopy and wire placement as used for percutaneous endoscopic gastrostomy placement was performed in five pigs. Prior to gastrotomy, four tissue anchors were placed in four quadrants (1 cm away from the wire). A 12-mm gastrotomy was created endoscopically using a combination of needle-knife and balloon dilation. After transgastric peritoneoscopy, the sutures were approximated using a device knotting element. One additional pair of sutures was placed after evaluation of the gastric closure. The animals underwent in vivo contrast fluoroscopy, methylene blue instillation, and bursting pressure studies for assessment of the closure site. RESULTS: All animals studied showed complete sealing of the gastrotomy site without evidence of leak on fluoroscopic imaging or at final postmortem intragastric methylene blue instillation. Improved insufflation ability following gastrotomy was also noted using this technique, which enhanced overall visualization during the closure. CONCLUSION: Positioning tissue anchors prior to creating a NOTES gastrotomy was a feasible and reliable method to perform gastric closure. Follow-up survival studies will be warranted to support these preliminary findings.

A novel approach for salvaging infected prosthetic mesh after ventral hernia repair.

BACKGROUND: Salvaging infected prosthetic material after ventral hernia repair is rarely successful. Most cases require mesh excision and complex abdominal wall reconstruction, with variable success rates. We report two cases of mesh salvage with a novel use of percutaneous drainage and antibiotic irrigation. CASES: Two patients developed infected seromas after laparoscopic ventral hernia repair. One patient with a remote history of methicillin-resistant Staphylococcus aureus (MRSA) mesh infection underwent laparoscopic ventral hernia repair with a 20 x 23-cm piece of Parietex composite mesh. Two weeks post-operatively, he developed fevers and MRSA was aspirated from the seroma. Another patient had a 32 x 33-cm piece of ePTFE placed for repair. He subsequently developed a massive seroma requiring repeated aspirations. Four months following the repair, he developed an infected seroma with Klebsiella pneumonia. Each patient underwent percutaneous drainage of their abscesses with a six-French-pigtail catheter under ultrasound guidance. After 2 weeks of parenteral antibiotics and clinical resolution, the patients were placed on 4 weeks of gentamicin irrigations (80 mg in 30 cc solution) via the drain three times per day. Once therapy was completed, the drains were removed. The first patient also remains on daily oral doxycycline for suppression for his MRSA. Both patients have remained free of clinical signs of infection at 12 and 16 months, respectively, following the completion of therapy. CONCLUSION: Percutaneous drainage followed by antibiotic irrigation is a potential alternative to prosthetic removal when treating infected mesh in carefully selected patients.

Endoscopic full-thickness resection of gastric tumors using a novel grasp-and-snare technique: feasibility in ex vivo and in vivo porcine models.

BACKGROUND AND STUDY AIMS: Endoscopic full-thickness resection (EFTR) is a less-invasive method of en bloc removal of gastrointestinal tract tumors. The aim of this study was to evaluate the feasibility of a grasp-and-snare EFTR technique using a novel tissue-lifting device that provides more secure tissue anchoring and manipulation. METHODS: EFTR of normal gastric tissue and model stomach tumors was performed using a double-channel therapeutic endoscope with a prototype tissue-lifting device through one channel and a prototype hexagonal snare through the other. The lifting device was advanced through the open snare and anchored to the gastric wall immediately adjacent the model tumor. The tissue-lifting device was then partially retracted into the endoscope, causing the target tissue, including tumor, to evert into the gastric lumen. The open snare was then placed distal to the tumor around uninvolved gastric tissue. Resection was performed with a blended electrosurgical current through the snare. In the live pigs, EFTR was followed by laparotomy to asses for complications. RESULTS: 24 EFTRs were performed -- 14 in explanted stomachs and 10 in live pigs. In total, 23/24 resections resulted in full-thickness gastric defects. Resection specimens measured up to 5.0 cm when stretched and pinned on a histology stage. Gross margins were negative in 17/20 model tumor resections. Two resections were complicated by gastric mural bleeding. There was no evidence of adjacent organ injury. CONCLUSIONS: EFTR of gastric tumors using the grasp-and-snare technique is feasible in pigs. This technique is advantageous in that eversion of the gastric wall avoids injury to external organs, continuous luminal insufflation is not required, and the involved techniques are familiar to endoscopists. Additional research is necessary to further evaluate safety and reliable closure.

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

BACKGROUND: The 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. METHODS: A 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. RESULTS: The 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. CONCLUSION: This 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.

Laparoscopic component separation in the single-stage treatment of infected abdominal wall prosthetic removal.

BACKGROUND: The ideal surgical treatment for complicated ventral hernias remains elusive. Traditional component separation provides local advancement of native tissue for tension-free closure without prosthetic materials. This technique requires an extensive subcutaneous dissection, with the division of perforating vessels predisposing to skin flap necrosis and complicated wound infections. The laparoscopic separation of components provides a minimally invasive alternative to open techniques, while eliminating the potential space and subsequent complications of large skin flaps. We report our initial experience with a minimally invasive component separation with early postoperative outcomes. METHODS: We retrospectively reviewed the medical records of all patients who underwent a minimally invasive component separation for abdominal wall reconstruction during the resection of an infected prosthetic. Pertinent details included baseline demographics, reason for contamination, operative technique and details, postoperative morbidity, mortality, and recurrence rates. RESULTS: Between August 2006 and January 2007, seven patients were identified who underwent a laparoscopic component separation. There were four males and three females, with a mean age of 54 years (range 34-84), mean American Society of Anesthesiologist (ASA) score of 3.2 (range 3-4), and mean body mass index (BMI) of 37 kg/m2 (range 30-45). The reason for contamination included exposed non-healing mesh (6) and contaminated fluid collection around the mesh (1). Residual defect size following the removal of all prosthetics was 338 cm2 (range 187-450). The mean operative time was 185 min (range 155-220). Laparoscopic component separation enabled tension-free primary fascial reapproximation in all patients. Three postoperative complications occurred, including superficial surgical site infection (1), respiratory failure (1), and hematoma (1). There was no mortality in this series. During an average follow-up period of 4.5 months, no recurrences were identified. CONCLUSIONS: This study shows that a minimally invasive component separation is feasible and can result in minimal postoperative wound morbidity in these complex patients. Long-term follow-up is necessary to evaluate the outcomes with respect to recurrence rates.

A reliable method for monitoring intraabdominal pressure during natural orifice translumenal endoscopic surgery.

BACKGROUND: Natural orifice translumenal endoscopic surgery (NOTES) provides surgical access to the peritoneal cavity without skin incisions. The NOTES procedure requires pneumoperitoneum for visualization and manipulation of abdominal organs, similar to laparoscopy. Accurate measurement of the pneumoperitoneum pressure is essential to avoid potentially deleterious effects of intraabdominal compartment syndrome. A reliable method for monitoring pneumoperitoneum pressures during NOTES has not been identified. This study evaluated several methods of monitoring intraabdominal pressures with a standard gastroscope during NOTES. METHODS: Four female pigs (25 kg) were sedated, and a single-channel gastroscope was passed transgastrically into the peritoneal cavity. Pneumoperitoneum was achieved via a pressure insufflator through a percutaneous, intraperitoneal 14-gauge catheter. Three other pressures were recorded via separate catheters. First, a 14-gauge percutaneous catheter passed intraperitoneally measured true intraabdominal pressure. Second, a 14-gauge tube attached to the endoscope was used to measure endoscope tip pressure. The third pressure transducer was connected directly to the accessory channel of the endoscope. The abdomen was insufflated to a range of pressures (10-30 mmHg), and simultaneous pressures were recorded from all three pressure sensors. RESULTS: Pressure correlation curves were developed for all animals across all intraperitoneal pressures (mean error, -4.25 to -1 mmHg). Endoscope tip pressures correlated with biopsy channel pressures (R2 = 0.99). Biopsy channel and endoscope tip pressures fit a least-squares linear model to predict actual intraabdominal pressure (R = 0.99 for both). Both scope tip and biopsy channel port pressures were strongly correlative with true intraabdominal pressures (R2 = 0.98 and R2 = 0.99, respectively). CONCLUSION: This study demonstrates that monitoring pressure through an endoscope is reliable and predictive of true intraabdominal pressure. Gastroscope pressure monitoring is a useful adjunct to NOTES. Future NOTES procedures should incorporate continuous intraabdominal pressure monitoring to avoid the potentially deleterious effects of pneumoperitoneum during NOTES. This can be achieved by the integration of pressure-monitoring capabilities into gastroscopes.

Diaphragm pacing with natural orifice transluminal endoscopic surgery: potential for difficult-to-wean intensive care unit patients.

BACKGROUND: Up to 50% of the patients in the intensive care unit (ICU) require mechanical ventilation, with 20% requiring the use of a ventilator for more than 7 days. More than 40% of this time is spent weaning the patient from mechanical ventilation. Failure to wean from mechanical ventilation can in part be attributable to rapid onset of diaphragm atrophy, barotrauma, posterior lobe atelectasis, and impaired hemodynamics, which are normally improved by maintaining a more natural negative chest pressure. The authors have previously shown that laparoscopic implantation of a diaphragm pacing system benefits selected patients. They now propose that an acute ventilator assist with interventional neurostimulation of the diaphragm in the ICU is feasible and could facilitate the weaning of ICU patients from mechanical ventilation. Natural orifice transluminal endoscopic surgery (NOTES) has the potential to expand the benefits of the diaphragm pacing system to this acute patient population by allowing it to be performed at the bedside similarly to insertion of the common gastrostomy tube. This study evaluates the feasibility of this approach in a porcine model. METHODS: Pigs were anesthetized, and peritoneal access with the flexible endoscope was obtained using a guidewire, needle knife cautery, and balloon dilation. The diaphragm was mapped using a novel endoscopic electrostimulation catheter to locate the motor point (where stimulation provides complete contraction of the diaphragm). An intramuscular electrode then was placed at the motor point with a percutaneous needle. The gastrotomy was managed with a gastrostomy tube. RESULTS: Four pigs were studied, and the endoscopic mapping instrument was able to map the diaphragm to identify the motor point. In one animal, a percutaneous electrode was placed into the motor point under transgastric endoscopic visualization, and the diaphragm could be paced in conjunction with mechanical ventilation. CONCLUSIONS: These animal studies demonstrate the feasibility of transgastric mapping of the diaphragm and implantation of a percutaneous electrode for therapeutic diaphragmatic stimulation.

Endoluminal surgery: past, present and future.

Flexible endoscopy has evolved from a diagnostic tool practiced predominantly by gastroenterologists to a minimally invasive surgical tool. Therapeutic endoluminal procedures have become the standard of care for many gastric, biliary, pancreatic and colonic maladies. New technologies are under investigation for endoscopic treatment of gastroesophageal reflux, morbid obesity, and ablation of premalignant tissue. In the future flexible endoscopes may play a role in "natural orifice" surgery, performing operations through the mouth or rectum without the need for external incisions.

SLiC technique. A novel approach to percutaneous gastrostomy.

BACKGROUND: Percutaneous endoscopic gastrostomy (PEG) has been an invaluable method for obtaining long-term enteral access and represents one of the first forays in the field of minimally invasive surgery. However, the traditional "pull" method for PEG tube placement continues to have some disadvantages, especially in patients with near-obstructive head and neck cancers. METHODS: We describe a new "SLiC" technique for establishing percutaneous gastrostomy using a radially expandable trocar. RESULTS: This technique is initially developed and refined on a porcine model and then successfully implemented on five human patients. CONCLUSION: The SLiC technique can be done safely and efficiently with a pediatric-sized gastroscope and avoids the need for radiation from fluoroscopy. It is a good alternative for obtaining enteral access in patients who would otherwise not be well suited for a traditional PEG tube.

Anterior gastropexy may reduce the recurrence rate after laparoscopic paraesophageal hernia repair.

BACKGROUND: Although laparoscopic repair of type 3 paraesophageal hernias is safe and results in symptomatic relief, recent data have questioned the anatomic integrity of the laparoscopic approach. The reports document an asymptomatic recurrence rate as high as 42% with radiologic follow-up evaluation for type 3 paraesophageal hernias repaired laparoscopically. This disturbingly high recurrence rate has prompted the addition of an anterior gastropexy to our standard laparoscopic paraesophageal hernia repair. METHODS: A prospective series of 28 patients underwent laparoscopic repair of large type 3 hiatal hernias between July 2000 and January 2002 at the Cleveland Clinic Foundation by one surgeon. All the patients underwent reduction of the hernia, sac excision, crural repair, antireflux procedure, and anterior gastropexy. They all had a video esophagram 24 h after surgery, then at 3-, 6-, and 12-month follow-up visits and annually thereafter. Symptomatic outcomes were assessed with a standard questionnaire at each follow-up visit. RESULTS: In this study, 21 women and 7 men with a mean age of 67 years (range, 35-82 years) underwent successful laparoscopic paraesophageal hernia repair. The mean operative time was 146 min (range, 101-186 min), and the average blood loss was 71 ml (range, 10-200 ml). One intraoperative complication occurred: A small esophageal mucosal tear occurred during esophageal dissection and was repaired laparoscopically. At 24 h, upper gastrointestinal examination identified no leaks. At this writing, all the patients have undergone video esophagram at a 3-month follow-up visit. All were asymptomatic and all examinations were normal. Of the 28 patients, 27 have undergone follow-up assessment at 6 months. At this writing, all the patients have undergone video esophagram at 3, 6, and 12 months follow up visits. All were asymptomatic and all examinations were normal. Ten patients have completed 2 year follow up barium swallows with no recurrences. CONCLUSIONS: With up to 2 years of follow-up evaluation, the addition of an anterior gastropexy to the laparoscopic repair of type 3 hiatal hernias resulted in no recurrences. These encouraging results necessitate further follow-up evaluation to document the long-term effects of anterior gastropexy in reducing postoperative recurrence after laparoscopic repair of paraesophageal hernias.

Gastric electrical stimulation at proximal stomach induces gastric relaxation in dogs.

Gastric electrical stimulation (GES) improves symptoms in patients with gastroparesis. However, the underlying mechanisms remain unclear. To determine if GES at proximal and distal stomach could affect the biomechanical properties of the stomach, thus contributing to the beneficial effect of GES. Four pairs of electrodes were implanted along the greater curvature of the stomach in seven dogs. Gastric tone and compliance was assessed with a barostat. Measurements were obtained randomly during control and proximal and distal stimulation (4 mA, 375 ms and 6/18 cpm). Data as mean or median (25-75th percentiles). Gastric compliance was not affected by proximal and distal GES. Gastric tone was significantly reduced during proximal GES: 82.0 (66.8, 89.1) mL vs control 49.7 (39.6,75.9) mL at 6 cpm (P = 0.016), and 90.6 (54.5, 117.9) mL vs control 62.8 (39.6, 75.9) mL at 18 cpm (P = 0.031). Tone was not affected by distal GES at 6 cpm: 95.8 (46.3, 106.7) mL vs control 75.2 (49.7, 86.1) mL (P = 0.47) and at 18 cpm: 80.4 (38.1, 170.3) mL vs control 62.8 (44.6, 156.3) mL (P = 0.44). Proximal GES induces gastric relaxation. This effect, if seen also in humans, may explain, in part, the symptomatic improvement associated with GES therapy in patients with gastroparesis.

Recurrence after laparoscopic ventral hernia repair.

BACKGROUND: Although the early results of laparoscopic ventral hernia repair have shown a low recurrence rate, there is a paucity of long-term data. This study reviews a single institution's experience with laparoscopic ventral hernia repair (LVHR). METHODS: We carried out a retrospective analysis of all LVHR performed at the Cleveland Clinic Foundation from January 1996 to March 2001. Recurrence rates were determined by physical exam or telephone follow-up. Factors predictive of recurrence were determined using Cox regression. RESULTS: Of 100 ventral hernias completed laparoscopically, 96 were available for long-term follow-up (average, 30 months; range 4-65). There were no deaths and major morbidity occurred in seven patients. Recurrences were identified in 17 patients. Nine recurrences occurred in the 1st postoperative year; however, hernia recurrence continued throughout the period of follow-up. Multivariate analysis showed that a prior failed hernia repair was associated with a more likely chance of another recurrence (65% vs 35%, odds ratio (OR) 3.6; p = 0.05) and that an increased estimated blood loss (106 cc vs 51 cc, OR 1.03; p = 0.005) predicted recurrence. Other variables, including body mass index (BMI) (32 vs 31 kg/m2, p = 0.38), defect size (115 cm2 vs 91 cm2; p = 0.23), size of mesh (468 cm2 vs 334 cm2, p = 0.19), type of mesh (p = 0.62), and mesh fixation (p = 0.99), did not predict recurrence. An additional 14 cases required conversion to an open operation, and seven of these cases (50%) had recurrence on long-term follow-up. CONCLUSION: Although LVHR remains the preferred method of hernia repair at our institution, this study documents a higher recurrence rate than many other short-term series. There results underscore the importance of long-term follow-up in assessing hernia surgery outcome.

MCP-1 is highly expressed in peritoneum following midline laparotomy with peritoneal abrasion in a murine model.

BACKGROUND: Monocyte chemoattractant protein-1 (MCP-1), a CC chemokine, is a potent attractant of monocytes both in vitro and in vivo. However, its role in the repair of peritoneal injury is not well established. This study characterizes MCP-1 expression in surgical wounds following peritoneal abrasion in a murine model. METHODS: Twenty-five C57 BL6 female mice underwent a 2-cm midline laparotomy with mechanical abrasion of the right peritoneal wall. The mice were sacrificed at various times ranging from 0 to 7 days. Hemotoxylin and eosin stained sections and tissue extracts were made using peritoneal samples from abraded and unabraded areas in each mouse. An enzyme-linked immunosorbent assay was performed on the specimens to quantitate MCP-1 expression. Values were compared using a t-test. RESULTS: At baseline, there was minimal expression of MCP-1 (<5 pg/mg protein). Following surgery, MCP-1 levels at abraded sites were significantly higher than those at both baseline and unabraded sites at all times up to a week following surgery. Histologic evaluation revealed peritoneal thickening and leukocytic infiltration of only abraded surfaces. CONCLUSION: MCP-1 is highly expressed in peritoneum following laparotomy with peritoneal abrasion. Elevations in MCP-1 levels are identified within 6 h of surgery and persist for up to 1 week. The histologic differences between abraded and unabraded areas may be attributable to differences in MCP-1 expression. Further studies using recombinant MCP-1 and anti-MCP-1 antibody may elucidate this relationship.