Marine-inspired molecular mimicry generates a drug-free, but immunogenic hydrogel adhesive protecting surgical anastomosis

Herein,we report the synthesis of a biomimic hydrogel adhesive that addresses the poor healing of surgical anastomosis.Dopamine-conjugated xanthan gum(Da-g-Xan)is fabricated using deep insights into the molecular similarity between mussels'adhesive and dopamine as well as the structural similarity between barnacle cement proteins and xanthan gum.The hydrogel mimics marine animals’adherence to wet tissue surfaces.Upon applying this adhesive to colonic anastomosis in a rat model,protective effects were shown by significantly improving the bursting pressure.Mechanistically,the architecture of Da-g-Xan hydrogel is maintained by dynamic intermolecular hydrogen bonds that allow the quick release of Da-g-Xan.The free Da-g-Xan can regulate the inflammatory status and induce type 2 macrophage polarization(M2)by specifically interacting with mannose receptors(CD206)revealed by RNA-sequencing and molecular binding assays.Consequently,an appropriate microenvironment for tissue healing is created by the secretion of chemokines and growth factors from M2 macrophages,strengthening the fibroblast migration and proliferation,collagen synthesis and epithelial vascularization.Overall,this study demonstrates an unprecedented strategy for generating an adhesive by synergistic mimicry inspired by two marine animals,and the results show that the Da-g-Xan adhesive augments native tissue regenerative responses,thus enabling enhanced recovery following surgical anastomosis.

Simulation and Experimental Study of Staple Line Reinforcement Surgery

The aim of this study was to evaluate the effectiveness of BM (basement membrane) and SIS (small intestine submucosa) composite extracellular matrix staple line reinforcement in surgical procedures through finite element modelling simulations and leak-proof performance experiments. The mechanical analyses of soft tissues with and without staple line reinforcement were performed by establishing finite element models of three tissues, namely, stomach, intestine and lungs, under the use scenarios of different anastomosis staple models;and the leak-proof performance of the staple line reinforcement was evaluated by simulating leak-proof experiments of gastric incision margins, intestinal sections, and lung incision margins in vitro. The results showed that the equivalent average stresses of the staple line reinforcement were increased by 20 kPa-68 kPa in gastric and intestinal tissues, and 8 kPa-22 kPa in lung tissues. and that the BM and SIS composite extracellular matrix staple line reinforcement could strengthen the anastomotic structure, and at the same time disperse the high stresses of the anastomosed tissues, which could effectively reduce the postoperative complications such as anastomotic bleeding and anastomotic leakage, and provide a safer and more effective optimized design for surgical mechanical anastomosis. It can effectively reduce postoperative complications such as anastomotic bleeding and anastomotic leakage, and provide a safer and more effective optimized design for surgical mechanical anastomosis.

Stem cell therapy applied for digestive anastomosis: Current state and future perspectives

BACKGROUND Digestive tract resections are usually followed by an anastomosis.Anastomotic leakage,normally due to failed healing,is the most feared complication in digestive surgery because it is associated with high morbidity and mortality.Despite technical and technological advances and focused research,its rates have remained almost unchanged the last decades.In the last two decades,stem cells(SCs)have been shown to enhance healing in animal and human studies;hence,SCs have emerged since 2008 as an alternative to improve anastomoses outcomes.AIM To summarise the published knowledge of SC utilisation as a preventative tool for hollow digestive viscera anastomotic or suture leaks.METHODS PubMed,Science Direct,Scopus and Cochrane searches were performed using the key words“anastomosis”,“colorectal/colonic anastomoses”,“anastomotic leak”,“stem cells”,“progenitor cells”,“cellular therapy”and“cell therapy”in order to identify relevant articles published in English and Spanish during the years of 2000 to 2021.Studies employing SCs,performing digestive anastomoses in hollow viscera or digestive perforation sutures and monitoring healing were finally included.Reference lists from the selected articles were reviewed to identify additional pertinent articles.METHODS Given the great variability in the study designs,anastomotic models,interventions(SCs,doses and vehicles)and outcome measures,performing a reliable meta-analysis was considered impossible,so we present the studies,their results and limitations.RESULTS Eighteen preclinical studies and three review papers were identified;no clinical studies have been published and there are no registered clinical trials.Experimental studies,mainly in rat and porcine models and occasionally in very adverse conditions such as ischaemia or colitis,have been demonstrated SCs as safe and have shown some encouraging morphological,functional and even clinical results.Mesenchymal SCs are mostly employed,and delivery routes are mainly local injections and cell sheets followed by biosutures(sutures coated by SCs)or purely topical.As potential weaknesses,animal models need to be improved to make them more comparable and equivalent to clinical practice,and the SC isolation processes need to be standardised.There is notable heterogeneity in the studies,making them difficult to compare.Further investigations are needed to establish the indications,the administration system,potential adjuvants,the final efficacy and to confirm safety and exclude definitively oncological concerns.CONCLUSION The future role of SC therapy to induce healing processes in digestive anastomoses/sutures still needs to be determined and seems to be currently far from clinical use.

Covered nitinol stents for the treatment of esophageal strictures and leaks

AIM:To compare 2 different types of covered esophageal nitinol stents(Ultraflex and Choostent) in terms of efficacy,complications,and long-term outcome.METHODS:A retrospective review of a consecutive series of 65 patients who underwent endoscopic placement of an Ultraflex stent(n = 33) or a Choostent(n = 32) from June 2001 to October 2009 was conducted.RESULTS:Stent placement was successful in all patients without hospital mortality.No significant differences in patient discomfort and complications were observed between the Ultraflex stent and Choostent groups.The median follow-up time was 6 mo(interquartile range 3-16 mo).Endoscopic reintervention was required in 9 patients(14%) because of stent migration or food obstruction.No significant difference in the rate of reintervention between the 2 groups was observed(P = 0.8).The mean dysphagia score 1 mo after stent placement was 1.9 ± 0.3 for the Ultraflex stent and 2.1 ± 0.4 for the Choostent(P = 0.6).At 1-mo follow-up endoscopy,the cover membrane of the stent appeared to be damaged more frequently in the Choostent group(P = 0.34).Removal of the Choostent was possible up to 8 wk without difficulty.CONCLUSION:Ultraflex and Choostent proved to be equally reliable for palliation of dysphagia and leaks.Removal of the Choostent was easy and safe under mild sedation.

咽胃吻合术后颈胃坏死折叠胸大肌肌皮瓣修补1例

1临床资料 患者,男,59岁。因进食呛咳1个月于2017-07-06入院,术前诊断：下咽恶性肿瘤、食管癌。患者于2017-07-13全麻下行＂气管切开术、全喉全下咽切除术、双侧颈淋巴结清扫术、气管造瘘术、食管切除术、胃上徙管状胃成形术、咽胃吻合术、空肠造瘘术＂。手术顺利,术后患者一般情况可,术后5天颈部引流管口有棕褐色液体流出,急诊手术探查,术中见颈部大量黄色脓性分泌物流出,颈段胃壁前份颜色淡黄色,无血运,上至舌根。

Application of a three-dimensional microsurgical video system for a rat femoral vessel anastomosis

Background The operating microscopes have been applied to modern surgery for nearly a century.However,generations of microsurgeons have to flex their necks and fix their eyes on the eyepieces of a microscope continually that leads to physical and mental fatigue during a long operation.Stereoscopic three-dimensional （3D） media provides more ergonomic working environment,subsequently,resulting better performance in tasks and more accurate judgment.In this study,an alternative method of magnification was analyzed using a three-dimensional microsurgical video system and compared with the traditional method under microscopy to evaluate the availability and feasibility of a 3D microsurgical video system for microvascular anastomosis.Methods Forty Sprague-Dawley rats were randomly divided into four groups with each of 10.In 20 rats,10 femoral artery anastomoses with a conventional microscope （arterial microscope group） were compared with that of 10 femoral artery anastomoses with a 3D microsurgical video system （arterial 3D group）.For the other 20 rats,10 femoral vein anastomoses using a conventional microscope （venous microscope group） were compared with that of 10 femoral vein anastomoses using a 3D microsurgical video system （venous 3D group）.The arterial and venous microscope groups were considered to be the control groups.The arterial and venous 3D groups were the experimental groups.The examined criteria were as follows：anastomotic time,patency right after the procedure and 10 days later,number of sutures,vessel caliber,and pathological features.Results There were no differences between the operating equipment with respect to vessel caliber,anastomotic time,patency rate,number of sutures,and pathological changes in either the small arteries or veins.The average arterial anastomotic time of the arterial microscope group and arterial 3D group was 34.21 and 33.87 minutes,respectively （P ＞0.05）.The average venous anastomotic time of the venous microscope group and venous 3D group was 29.95 and 31.50 minutes,respectively （P ＞0.05）.Conclusions A small vessel anastomosis can be performed successfully with the help of a 3D display system.Although the vascular anastomotic time did not demonstrate a significant difference between the groups,the 3D microsurgical video system offers another option to improve the working environment for surgeons.Further development of our 3D monitoring system should focus on a higher resolution and better flexibility.

Sutureless choledochoduodenostomy with an intraluminal degradable stent in dog model

Background It is difficult and time-consuming for carrying out conventional hand-sewn bilioenteric anastomosis, especially for small bile duct anastomosis and laparoscopic procedure. In order to simplify it, we have developed a novel procedure of sutureless bilioenteric anastomosis with an intraluminal degradable stent. This study aimed to evaluate the feasibility and safety of this technique with cholangioduodenostomy in dog model. Methods A patent intraluminal degradable stent tube for sutureless choledochoduodenostomy in dog model was made with polylactic acid in diameter of 3 mm or 4 mm. Thirty-eight dogs were randomly divided into to a stent group （SG, n=20） and a control group （CG, n=18）. Dogs in the SG underwent sutureless choledochoduodenostomy with intraluminal stent, while the CG underwent conventional choledochoduodenostomy （single layer discontinuous anastomosis with absorbable suture）. Dogs of each group were divided into 4 subgroups according to time of death （1,3, 6, and 12 months postoperatively） to evaluate the healing of anastomosis. Operation time, intraoperative tolerance pressure of anastomosis, rate of postoperative bile leakage, bursting pressure of anastomosis were compared between the two groups. Anastomosis tissue was observed afterwards by pathology evaluation, hydroxyproline content, serum bilirubin, liver enzyme level and magnetic resonance cholangio-pancreatography （MRCP） to assess the stricture. Results All procedures were completed successfully. The surgical time of the SG was significantly less than the CG （SG： （19.2±4.3） minutes, vs. CG： （29.2±7.1） minutes, P=0.000）. One bile leakage was occurred in either group. No significant difference of intraoperative tolerance pressure of anastomosis, rate of bile leakage and postoperative bursting pressure of anastomosis, anastomotic stricture, hydroxyproline content, serum bilirubin and liver enzyme level was found between the two groups. MRCP showed no anastomosis stricture and obstruction during months of follow-up. Conclusion The technique of sutureless choledochoduodenostomy with a degradable intraluminal stent is feasible and a safe procedure in this dog model.

A novel method for reconstruction in laparoscopic pancreaticoduodenectomy:an experience of 13 cases

Laparoscopic pancreaticoduodenectomy(LPD)is a challenging operation to general surgeon.Up to date,only about 135 cases have been reported,16 cases in China,119 cases outside China.The reconstruction of alimentary system is a key procedure to ensure success of the whole surgery.It is worth investigating the methods of reconstruc-tion in LPD.A retrospective study is made to investigate the methods of reconstruction in LPD.We analyze 13 cases of LPD performed in our center.Child’s or modified Child’s method was used to make the reconstruction in our practice.We tried three methods to make the anastomosis of pancre-aticojejunostomy,including end-to-end dunking binding pancreaticojejunostomy in two cases,end-to-end dunking pancreaticojejunostomy using interrupted suture in two cases,and duct-to-jejunal end-to-side embedding pancreaticojeju-nostomy in nine cases.The clinical data was collected and analyzed.Three of four patients,who underwent end-to-end pancreaticojejunostomy,had a little pancreatic leakage,especially in the first case.None of other nine patients,who underwent duct-to-jejunal end-to-side embedding pancreati-cojejunostomy,was detected to have pancreatic leakage,and the operating time of these nine cases was less than other four cases.Duct-to-jejunal end-to-side embedding pancreaticoje-junostomy is a safe and efficient method of reconstruction in LPD.