Endoscopic dilation of esophageal stricture without fluoroscopy is safe and effective

AIM: Endoscopic dilation of esophageal strictures is acommonly performed procedure in the management ofdysphagia. The procedure is usually done withfluoroscopic guidance. The aim of this study was toassess the use of Tracer guide wire in conjunction withSavary-Gilliard dilators in the dilation of tightesophageal strictures without fluoroscopy.METHODS: Fifty-five patients with significant dysphagiafrom strictures due to a variety of causes were dilatedendoscopically. The procedure consisted of two parts.First, a guidewire was passed using endoscopic guidance,and then, dilation was performed without fiuoroscopy.Amodified Tracer wire was employed and was particularlyeffective in negotiating very tight esophageal strictures,in which the lumen is less than 6 mm. In general, the'Rule of Three' and '2-3 sessions in 10 days, maximumdilation up to 42 French' rules were followed. 40:1dilations in a total of 55 patients(malignant strictures 30,benign 25) in 177 sessions were carried out.RESULTS: The guide wire placement and Savary-Gilliarddilation were successfully performed without fluoroscopy,and improvement of dysphagia was achieved in allpatients. Esophageal plastic stent (out diameter 40French) was placed in five patients with malignantstricture-three of them with tracheo-esophageal fistula.CONCLUSION: Dilation using Tracer guide wire withoutfluoroscopy is safe and effective in treatment of evenvery tight esophageal strictures.

Natural orifice transluminal endoscopic wedge hepatic resection with a water-jet hybrid knife in a non-survival porcine model

AIM: To explore the feasibility of a water-jet hybrid knife to facilitate wedge hepatic resection using a natural orifice transluminal endoscopic surgery (NOTES) approach in a non-survival porcine model. METHODS: The Erbe Jet2 water-jet system allows a needleless, tissue-selective hydro-dissection with a pre-selected pressure. Using this system, wedge hepatic resection was performed through three natural routes (trans-anal, trans-vaginal and trans-umbilical) in three female pigs weighing 35 kg under general anesthesia. Entry into the peritoneal cavity was via a 15-mm incision using a hook knife. The targeted liver segment was marked by an APC probe, followed by wedge hepatic resection performed using a water-jet hybrid knife with the aid of a 4-mm transparent distance soft cap mounted onto the tip of the endoscope for holding up the desired plane. The exposed vascular and ductal structures were clipped with Endoclips. Hemostasis was applied to the bleeding cut edges of the liver parenchyma by electrocautery. After the procedure, the incision site was left open, and the animal was euthanized followed by necropsy. RESULTS: Using the Erbe Jet2 water-jet system, trans-anal and trans-vaginal wedge hepatic resection was successfully performed in two pigs without laparoscopic assistance. Trans-umbilical attempt failed due to an unstable operating platform. The incision for peritoneal entry took 1 min, and about 2 h was spent on excision of the liver tissue. The intra-operative blood loss ranged from 100 to 250 mL. Microscopically, the hydro-dissections were relatively precise and gentle, preserving most vessels. CONCLUSION: The Erbe Jet2 water-jet system can safely accomplish non-anatomic wedge hepatic resection in NOTES, which deserves further studies to shorten the dissection time.

Trans-umbilical endoscopic cholecystectomy with a water-jet hybrid-knife:A pilot animal study

AIM:To investigate the feasibility and safety of Natural orifice trans-umbilical endoscopic cholecystectomy with a water-jet hybrid-knife in a non-survival porcine model.METHODS:Pure natural orifice transluminal endoscopic surgery(NOTES) cholecystectomy was performed on three non-survival pigs,by transumbilical approach,using a water-jet hybrid-knife. Under general anesthesia,the following steps detailed the procedure:(1) incision of the umbilicus followed by the passage of a double-channel flexible endsocope through an overtube into the peritoneal cavity;(2) establishment of pneumoperitoneum;(3) abdominal exploration;(4)endoscopic cholecystectomy:dissection of the gallbladder performed using water jet equipment,ligation of the cystic artery and duct conducted using nylon loops;and(5) necropsy with macroscopic evaluation.RESULTS:Transumbilical endoscopic cholecystectomy was successfully completed in the first and third pig,with minor bleedings. The dissection times were 137and 42 min,respectively. The total operation times were 167 and 69 min,respectively. And the lengths of resected specimen were 6.5 and 6.1 cm,respectively.Instillation of the fluid into the gallbladder bed produced edematous,distended tissue making separation safe and easy. Reliable ligation using double nylon loops insured the safety of cutting between the loops.There were no intraoperative complications or hemodynamic instability. Uncontrolled introperative bleeding occurred in the second case,leading to the operation failure.CONCLUSION:Pure NOTES trans-umbilical cholecystectomy with a water-jet hybrid-knife appears to be feasible and safe. Further investigation of this technique with long-term follow-up in animals is needed to confirm the preliminary observation.

Transgastric endoscopic gastrojejunostomy using holing followed by interrupted suture technique in a porcine model

AIM: To demonstrate the feasibility and reproducibility of a pure natural orifice transluminal endoscopic surgery(NOTES) gastrojejunostomy using holing followed by interrupted suture technique using a single endoloop matched with a pair of clips in a non-survival porcine model.METHODS: NOTES gastrojejunostomy was performed on three female domestic pigs as follows: Gastrostomy, selection and retrieval of a free-floating loop of the small bowel into the stomach pouch, hold and exposure of the loop in the gastric cavity using a submucosal inflation technique, execution of a gastro-jejunal mucosal-seromuscular layer approximation using holing followed by interrupted suture technique with endoloop/clips, and full-thickness incision of the loop with a Dual knife.RESULTS: Pure NOTES side-to-side gastrojejunostomy was successfully performed in all three animals. No leakage was identified via methylene blue evaluation following surgery.CONCLUSION: This novel technique for preforming a gastrointestinal anastomosis exclusively by NOTES is technically feasible and reproducible in an animal model but warrants further improvement.

Percutaneous transgastric endoscopic tube ileostomy in a porcine survival model

AIM To introduce natural orifice transgastric endoscopic surgery(NOTES) tube ileostomy using pelvis-directed submucosal tunneling endoscopic gastrostomy and endoscopic tube ileostomy.METHODS Six live pigs(three each in the non-survival and survival groups) were used. A double-channeled therapeutic endoscope was introduced perorally into the stomach. A gastrostomy was made using a 2-cmtransversal mucosal incision following the creation of a 5-cm longitudinal pelvis-directed submucosal tunnel. The pneumoperitoneum was established via the endoscope. In the initial three operations of the series, a laparoscope was transumbilically inserted for guiding the tunnel direction, intraperitoneal spatial orientation and distal ileum identification. Endoscopic tube ileostomy was conducted by adopting an introducer method and using a Percutaneous Endoscopic Gastrostomy Catheter Kit equipped with the Loop Fixture. The distal tip of the 15 Fr catheter was placed toward the proximal limb of the ileum to optimize intestinal content drainage. Finally, the tunnel entrance of the gastrostomy was closed using nylon endoloops with the aid of a twin grasper. The gross and histopathological integrity of gastrostomy closure and the abdominal wall-ileum stoma tract formation were assessed 1 wk after the operation.RESULTS Transgastric endoscopic tube ileostomy was successful in all six pigs, without major bleeding. The mean operating time was 71 min(range: 60-110 min). There were no intraoperative complications or hemodynamic instability. The post-mortem, which was conducted 1-wk postoperatively, showed complete healing of the gastrostomy and adequate stoma tract formation of ileostomy.CONCLUSION Transgastric endoscopic tube ileostomy is technically feasible and reproducible in an animal model, and this technique is worthy of further improvement.

Extreme precipitation over northern China in autumn 2021 and joint contributions of tropical and mid-latitude factors

Frequent heavy precipitation and severe flood disasters struck northern China in early autumn 2021,with seven provinces/municipalities surpassing their precipitation records since 1961.Causes for such extreme events from the climate perspective are unclear because the variability of autumn precipitation in northern China is poorly understood.This study revealed that the event was directly caused by the extremely north-westward location of the western Pacific subtropical high(WPSH),which was jointly induced by several tropical and mid-latitude factors.The developing La Niña and warmer than normal tropical Atlantic sea surface temperature altered the Pacific Walker Circulation and enhanced the convection over the tropical western Pacific.Meanwhile,the Madden-Julian Oscillation stagnated for a long time in its phases 3-5 in early autumn and contributed constructively to the active convection over the tropical eastern Indian Ocean and western Pacific.These effects altogether excited a lower-tropospheric cyclone anomaly to the west of the Philippines and shifted the WPSH northwestwards in early autumn.A mid-latitude cyclonic centre was also observed upstream of East Asia.It dispersed Rossby wave energy southeastwards in the form of cold air invasions.The resultant convergence of cold and dry air from the north with warm and moist air from the south together caused extreme precipitation over northern China in autumn 2021.Relevant conclusions can enhance our current understanding of the causes of autumn extreme precipitation events in northern China and improve our ability to predict such events and prevent resultant disasters.