Henry Córdova

Yes, we can: reliable colonic closure with the Padlock-G clip in a survival porcine study (with video).

BACKGROUND Secure closure of the colonic access site is one of the most important issues for the development of natural orifice transluminal endoscopic surgery. OBJECTIVE To evaluate the feasibility, reproducibility, and efficacy of a new over-the-scope clip. DESIGN Descriptive study, in vivo porcine colon. INTERVENTION In 10 female Yorkshire pigs weighing 30 to 35 kg, a 10-mm colotomy was performed by using a needle-knife and advancing the endoscope to the peritoneal cavity. Colonic closure was performed by using the Padlock-G clip (Aponos Medical, Kingston, NH) delivered with the Lock-It system (Aponos). MAIN OUTCOME MEASUREMENTS Animals were monitored daily for signs of peritonitis and sepsis over a period of 14 days. During necropsy, the peritoneal cavity was examined, and the colon segment containing the incision was excised for pathological study. RESULTS Closure was achieved in all cases. Nine of 10 pigs survived 14 days without complications, but 1 pig was killed immediately after the procedure because of severe bleeding during the colonic incision. The median closure time was 8 minutes (range 1-30 minutes). At necropsy, adhesions were observed in 5 cases. The incision was hardly visible at the serosa side in 3 cases and was not identified in 6 cases. In 6 cases, the clip was still slightly attached to the mucosa, and it was not found in 3 cases. The pathological study revealed a complete remodeling of the colonic wall in all cases. LIMITATIONS Animal model, noncomparative study. CONCLUSION The Padlock-G clip procedure is feasible, reproducible, effective, and easy to perform, and it provides a reliable colonic closure.

Comparative Validation of Polyp Detection Methods in Video Colonoscopy: Results From the MICCAI 2015 Endoscopic Vision Challenge

Colonoscopy is the gold standard for colon cancer screening though some polyps are still missed, thus preventing early disease detection and treatment. Several computational systems have been proposed to assist polyp detection during colonoscopy but so far without consistent evaluation. The lack of publicly available annotated databases has made it difficult to compare methods and to assess if they achieve performance levels acceptable for clinical use. The Automatic Polyp Detection sub-challenge, conducted as part of the Endoscopic Vision Challenge (http://endovis.grand-challenge.org) at the international conference on Medical Image Computing and Computer Assisted Intervention (MICCAI) in 2015, was an effort to address this need. In this paper, we report the results of this comparative evaluation of polyp detection methods, as well as describe additional experiments to further explore differences between methods. We define performance metrics and provide evaluation databases that allow comparison of multiple methodologies. Results show that convolutional neural networks are the state of the art. Nevertheless, it is also demonstrated that combining different methodologies can lead to an improved overall performance.

The role of a computed tomography-based image registered navigation system for natural orifice transluminal endoscopic surgery: a comparative study in a porcine model.

BACKGROUND AND STUDY AIMS Most natural orifice transluminal endoscopic surgery (NOTES) procedures have been performed in animal models through the anterior stomach wall, but this approach does not provide efficient access to all anatomic areas of interest. Moreover, injury of the adjacent structures has been reported when using a blind access. The aim of the current study was to assess the utility of a CT-based (CT: computed tomography) image registered navigation system in identifying safe gastrointestinal access sites for NOTES and identifying intraperitoneal structures. METHODS A total of 30 access procedures were performed in 30 pigs: anterior gastric wall (n = 10), posterior gastric wall (n = 10), and anterior rectal wall (n = 10). Of these, 15 procedures used image registered guidance (IR-NOTES) and 15 procedures used a blind access (NOTES only). Timed abdominal exploration was performed with identification of 11 organs. The location of the endoscopic tip was tracked using an electromagnetic tracking system and was recorded for each case. Necropsy was performed immediately after the procedure. The primary outcome was the rate of complications; secondary outcome variables were number of organs identified and kinematic measurements. RESULTS A total of 30 animals weighting a mean (± SD) of 30.2 ± 6.8 kg were included in the study. The incision point was correctly placed in 11 out of 15 animals in each group (73.3 %). The mean peritoneoscopy time and the number of properly identified organs were equivalent in the two groups. There were eight minor complications (26.7 %), two (13.3 %) in the IR-NOTES group and six (40.0 %) in the NOTES only group ( P = n. s.). Characteristics of the endoscope tip path showed a statistically significant improvement in trajectory smoothness of motion for all organs in the IR-NOTES group. CONCLUSION The image registered system appears to be feasible in NOTES procedures and results from this study suggest that image registered guidance might be useful for supporting navigation with an increased smoothness of motion.

Infection during Natural Orifice Transluminal Endoscopic Surgery Peritoneoscopy: A Randomized Comparative Study in a Survival Porcine Model

BACKGROUND Infection in natural orifice transluminal endoscopic surgery (NOTES) remains controversial. OBJECTIVE To estimate the frequency of infection during NOTES peritoneoscopy with different routes of access and to compare with laparoscopy. DESIGN Prospective randomized controlled study (Canadian Classification type I). METHODS Forty female pigs were randomly assigned to 3 NOTES (transgastric, transrectal, and transvaginal) and laparoscopic groups. Antiseptic technique was used for NOTES, whereas laparoscopy was performed in a sterile environment. Preoperative and postoperative intravenous antibiotics were administered. Closure of the transluminal access site was performed in all animals. Peritoneal fluid was collected for culture at the end of surgery and at necropsy at day 14. RESULTS Thirty-nine peritoneoscopies were successfully completed. Necropsy confirmed complete healing of NOTES incisions, but 2 animals in the laparoscopy group had small abscesses in the abdominal incisions. There were no statistical differences in the presence of peritoneal adhesions. Positive culture results were seen in all groups at the end of the procedure and in all animals at necropsy, but this did not lead to clinical signs of gross infection. The most common organisms that colonized the peritoneum were gram-positive cocci and gram-negative bacilli from the normal swine gastrointestinal flora. LIMITATIONS Animal model and small sample size. CONCLUSIONS In these small series of animals and with the careful lavage and preparation used, NOTES appeared to be comparable to laparoscopy in terms of peritoneal contamination and clinical infection. Despite the adherence to a strict antiseptic protocol, peritoneal contamination occurs but does not lead to septic complications in the swine.

Exploring the clinical potential of an automatic colonic polyp detection method based on the creation of energy maps.

BACKGROUND AND AIMS Polyp miss-rate is a drawback of colonoscopy that increases significantly for small polyps. We explored the efficacy of an automatic computer-vision method for polyp detection. METHODS Our method relies on a model that defines polyp boundaries as valleys of image intensity. Valley information is integrated into energy maps that represent the likelihood of the presence of a polyp. RESULTS In 24 videos containing polyps from routine colonoscopies, all polyps were detected in at least one frame. The mean of the maximum values on the energy map was higher for frames with polyps than without (P < 0.001). Performance improved in high quality frames (AUC = 0.79 [95 %CI 0.70 - 0.87] vs. 0.75 [95 %CI 0.66 - 0.83]). With 3.75 set as the maximum threshold value, sensitivity and specificity for the detection of polyps were 70.4 % (95 %CI 60.3 % - 80.8 %) and 72.4 % (95 %CI 61.6 % - 84.6 %), respectively. CONCLUSION Energy maps performed well for colonic polyp detection, indicating their potential applicability in clinical practice.

On-demand endoscopic CO2 insufflation with feedback pressure regulation during natural orifice transluminal endoscopic surgery (NOTES) peritoneoscopy induces minimal hemodynamic and respiratory changes

BACKGROUND Endoscopic insufflation has been associated with marked increase in intra-abdominal pressure (IAP) and hemodynamic and respiratory changes during transgastric surgery. OBJECTIVE To investigate the hemodynamic and respiratory effects during intraperitoneal cavity exploration through 3 different natural orifice transluminal endoscopic surgery (NOTES) access locations compared with laparoscopy. DESIGN AND SETTING Survival experiments using 40 female pigs randomized to transgastric, transcolonic, transvaginal, and laparoscopic peritoneoscopy. INTERVENTIONS On-demand endoscopic insufflation of CO(2) with feedback pressure regulation was used in NOTES with a maximum pressure of 14 mm Hg. In the laparoscopy group, the IAP was maintained at 14 mm Hg. NOTES procedures were performed by an endoscopist (with the assistance of a gynecologist in the transvaginal group and a second endoscopist in the transgastric and transrectal groups) and laparoscopy by 2 surgeons. MAIN OUTCOME MEASUREMENTS Invasive hemodynamic and respiratory data. Blood samples were drawn for gas analyses. RESULTS All experiments except one in the transrectal group were completed. The IAP was significantly lower in all NOTES groups compared with the laparoscopy group. A significant increase in mean systemic arterial blood pressure was observed in the laparoscopy group at 15 and 30 minutes of intraperitoneal cavity exploration, but it remained unchanged during all NOTES procedures. An increase in airway pressures was observed at 15 and 30 minutes of peritoneoscopy in the animals undergoing laparoscopy, whereas those parameters remained unchanged in the NOTES groups. The laparoscopy group showed a significant impairment in pulmonary gas exchange (decrease in Pao(2), increase in Paco(2), and decrease in arterial pH) after 30 minutes of peritoneoscopy, whereas only a slight increase in Paco(2) was observed in the transrectal and transvaginal groups. LIMITATIONS Healthy animal model. CONCLUSION On-demand endoscopic insufflation of CO(2) with feedback pressure regulation can minimize the risk of hemodynamic and respiratory compromise caused by acute changes in IAP.

Gastrotomy closure with a new tissue anchoring device: A porcine survival study

AIM To evaluate the feasibility, reproducibility and efficacy of a new tissue anchoring device in a porcine survival model. METHODS Gastrotomies were performed using a needle-knife and balloon dilator in 10 female Yorkshire pigs weighing 30-35 kg. Gastric closure was attempted using a new tissue anchoring device. The tightness of the closure was confirmed by means of air insufflation and the ability to maintain gastric distension with stability in peritoneal pressure measured with a Veress needle. All animals were monitored daily for signs of peritonitis and sepsis over 14 d. During necropsy, the peritoneal cavity and the gastric access site were examined. RESULTS Transgastric access, closure and 14 d survival was achieved in all pigs. The mean closure time was 18.1 ± 19.2 min and a mean of 2.1 ± 1 devices were used. Supplementary clips were necessary in 2 cases. The closure time was progressively reduced (24.8 ± 13.9 min in the first 5 pigs vs 11.4 ± 5.9 min in the last 5, P = NS). At necropsy, the gastric access site was correctly closed in all cases with all brace-bars present. One device was misplaced in the mesocolon. Minimal adhesions were observed in 3 pigs and signs of mild peritonitis and adhesions in one. CONCLUSIONS The use of this new tissue anchoring device in porcine stomachs is feasible, reproducible and effective and requires a short learning curve.

Cardiorespiratory Impact of Transesophageal Endoscopic Mediastinoscopy Compared With Cervical Mediastinoscopy A Randomized Experimental Study

Background. Transesophageal natural-orifice transluminal endoscopic surgery (NOTES) mediastinoscopy has been described as a feasible, less-invasive alternative to video-assisted mediastinoscopy (VAM). We aimed to investigate hemodynamic and respiratory effects during transesophageal NOTES mediastinoscopy compared with VAM. Patients and methods. This was a short-survival experiment in 20 female pigs randomized to NOTES (n = 10) or VAM (n = 10) mediastinoscopy. In the NOTES group, an endoscopist accessed the mediastinum through a 5-cm submucosal tunnel in the esophageal wall, and CO2 was used to create the pneumomediastinum. Conventional VAM was carried out by thoracic surgeons. A 30-minute systematic exploration of the mediastinum was then performed, including invasive monitoring for hemodynamic and respiratory data. Blood samples were drawn for gas analyses. Results. All experiments except 2 in the NOTES group (one because of technical difficulties, the other because of thoracic lymphatic duct lesion) were completed as planned, and animals survived 24 hours. Also, 3 animals in the NOTES group presented a tension pneumothorax that was immediately recognized and percutaneously drained. VAM and NOTES animals showed similar pulmonary and systemic hemodynamic behavior during mediastinoscopy. Pulmonary gas exchange pattern was mildly impaired during the NOTES procedure, showing lower partial arterial oxygen pressure associated with higher airway pressures (more important in animals that presented with pneumothorax). Conclusions. NOTES mediastinoscopy induces minimal deleterious respiratory effects and hemodynamic changes similar to conventional cervical VAM and could be feasible when performed under strict hemodynamic and respiratory surveillance. Notably, serious complications caused by the injury of pleura are more frequent in NOTES, which mandates an improvement in technique and suitable equipment.

Gastric emptying is delayed in transgastric NOTES: a randomized study in swine.

AIM The aim of this study was to evaluate the restoration of gastrointestinal motility after NOTES using capsule endoscopy (CE). MATERIALS AND METHODS Twenty adult Yorkshire pigs were randomly assigned to four groups: transgastric NOTES (gNOTES), transrectal NOTES (rNOTES), transvaginal NOTES (vNOTES), and laparoscopy (LAP). At the end of a 30-min peritoneoscopy with identification of seven predetermined organs, an array of eight receivers and the recorder were attached to the abdominal wall. The CE was delivered into the antrum with the help of an endoscope and a polypectomy snare. Animals were kept alive for 14 d. RESULTS Median time for surgery was longer in gNOTES (56 min, range 47-63) and vNOTES (54 min, range 44-79) than in LAP (32 min, range 32-33; P < 0.05 and P < 0.01) and in rNOTES (45.5 min, range 33-56) (P = ns). This increase was related to a larger incision and longer closure times. Images from the CE were successfully retrieved in 19 cases. The CE was retained in the stomach in all animals in gNOTES (459 min; range 360-600), but only in one animal in rNOTES and vNOTES and in none in the LAP group. Failure of passage of the CE beyond the stomach was associated with gNOTES and longer closure of the incision. Animals in the gNOTES group gained less weight than the others and this change was statistical significant when compared with vNOTES animals (1.7 kg, range -1.98 to 4.5 versus 8.4 kg, range 5.8 to 11.45; P < 0.01). CONCLUSION Gastric emptying is delayed after gNOTES peritoneoscopy compared with rNOTES, vNOTES, and LAP and this effect is associated with less weight gain.

Adverse events of NOTES mediastinoscopy compared to conventional video-assisted mediastinoscopy: a randomized survival study in a porcine model

Background: Safety is a concern in natural orifice transluminal endoscopic surgery (NOTES) mediastinoscopy. The objective of this study was to compare the safety of NOTES mediastinoscopy with video-assisted mediastinoscopy (VAM). Methods: Twenty-four pigs were randomly assigned to NOTES or VAM. Thirty-minute mediastinoscopies were performed with the identification of seven predetermined structures. The animals were euthanized after 7 days and necropsy was performed. Results: Mediastinoscopy was not possible in one animal in each group. There were more intraoperative adverse events with NOTES than VAM (7 vs. 2, P = 0.04); hemorrhage was the most frequent adverse event (4 and 1, respectively). At necropsy, pathological findings were observed in 13 animals (9 NOTES and 4 VAM; P = 0.03). Inflammatory parameters were not different between groups and were not related to adverse events. Conclusion: Systematic NOTES mediastinoscopy is possible and comparable to VAM in terms of number of organs identified and inflammatory impact. However, the safety profile of NOTES mediastinoscopy has to be improved before it can be adopted in a clinical setting.