AIM:To investigate whether bile duct angulation and T-tube choledochostomy influence the recurrence of choledocholithiasis.METHODS:We conducted a retrospective study including 259 patients who underwent endoscopic sph...AIM:To investigate whether bile duct angulation and T-tube choledochostomy influence the recurrence of choledocholithiasis.METHODS:We conducted a retrospective study including 259 patients who underwent endoscopic sphincterotomy and cholecystectomy for choledocholithiasis between 2000 and 2007.The imaginary line was drawn along the center of the bile duct and each internal angle was measured at the two angulation sites ofthe bile duct respectively.The values of both angles were added together.We then tested our hypothesis by examining whether T-tube choledochostomy was performed and stone recurrence occurred by reviewing each subject's medical records.RESULTS:The overall recurrence rate was 9.3% (24 of 259 patients).The mean value of sums of angles in the recurrence group was 268.3°± 29.6°,while that in the non-recurrence group was 314.8°± 19.9° (P < 0.05).Recurrence rate of the T-tube group was 15.9% (17 of 107),while that of the non T-tube group was 4.6% (7 of 152) (P < 0.05).Mean value of sums of angles after T-tube drainage was 262.5°± 24.6° and that before T-tube drainage was 298.0°± 23.9° in 22 patients (P < 0.05).CONCLUSION:The bile duct angulation and T-tube choledochostomy may be risk factors of recurrence of bile duct stones.展开更多
AIM: To evaluate clinical outcomes of patients that underwent surgery, transarterial embolization (TAE), or supportive care for spontaneously ruptured hepatocellular carcinoma (HCC). METHODS: A consecutive 54 patients...AIM: To evaluate clinical outcomes of patients that underwent surgery, transarterial embolization (TAE), or supportive care for spontaneously ruptured hepatocellular carcinoma (HCC). METHODS: A consecutive 54 patients who diagnosed as spontaneously ruptured HCC at our institution between 2003 and 2012 were retrospectively enrolled. HCC was diagnosed based on the diagnostic guidelines issued by the 2005 American Association for the Study of Liver Diseases. HCC rupture was defined as disruption of the peritumoral liver capsule with enhanced fluid collection in the perihepatic area adjacent to the HCC by dynamic liver computed tomography, and when abdominal paracentesis showed an ascitic red blood cell count of > 50000 mm 3 /mL in bloody fluid. RESULTS: Of the 54 patients, 6 (11.1%) underwent surgery, 25 (46.3%) TAE, and 23 (42.6%) supportive care. The 2-, 4and 6-mo cumulative survival rates at 2, 4 and 6 mo were significantly higher in the surgery (60%, 60% and 60%) or TAE (36%, 20% and 20%) groups than in the supportive care group (8.7%, 0% and 0%), respectively (each, P < 0.01), and tended to be higher in the surgical group than in the TAE group. Multivariate analysis showed that serum bilirubin (HR = 1.09, P < 0.01), creatinine (HR = 1.46, P = 0.04), and vasopressor requirement (HR = 2.37, P = 0.02) were significantly associated with post-treatment mortality, whereas surgery (HR = 0.41, P < 0.01), and TAE (HR = 0.13, P = 0.01) were inversely associated with posttreatment mortality. CONCLUSION: Post-treatment survival after surgery or TAE was found to be better than after supportive care, and surgery tended to provide better survival benefit than TAE.展开更多
Duodenal perforation during endoscopic retrograde cholangiopancreatography(ERCP) is a rare complication,but it has a relatively high mortality risk.Early diagnosis and prompt management are key factors for the success...Duodenal perforation during endoscopic retrograde cholangiopancreatography(ERCP) is a rare complication,but it has a relatively high mortality risk.Early diagnosis and prompt management are key factors for the successful treatment of ERCP-related perforation.The management of perforation can initially be conservative in cases resulting from sphincterotomy or guide wire trauma.However,the current standard treatment for duodenal free wall perforation is surgical repair.Recently,several case reports of endoscopic closure techniques using endoclips,endoloops,or fully covered metal stents have been described.We describe four cases of iatrogenic duodenal bulb or lateral wall perforation caused by the scope tip that occurred during ERCP in tertiary referral centers.All the cases were simply managed by endoclips under transparent capassisted endoscopy.Based on the available evidence and our experience,endoscopic closure was a safe and feasible method even for duodenoscope-induced perforations.Our results suggest that endoscopists may be more willing to use this treatment.展开更多
Mechanical lithotripsy(ML) is usually considered as a standard treatment option for large bile duct stones.However,it is impossible to retrieve oversized stones because the conventional lithotripsy basket may not be a...Mechanical lithotripsy(ML) is usually considered as a standard treatment option for large bile duct stones.However,it is impossible to retrieve oversized stones because the conventional lithotripsy basket may not be able to grasp the stone.However,there is no established endoscopic extraction method for such giant stone removal.We describe a case of successful extraction of a 4-cm large stone using a gastric bezoar basket.A 78-year-old woman had suffered from upper abdominal pain for 20 d.Contrast-enhanced computed tomogram revealed a 4-cm single stone in the distal common bile duct(CBD).Endoscopic stone retraction was decided upon and endoscopic papillary balloon dilation was performed using a large balloon.An attempt to capture the stone using a standard lithotripsy basket failed due to the large stone size.Subsequently,we used a gastric bezoar basket to successfully capturethe stone.The stone was fragmented into small pieces and extracted.The stone was completely removed after two sessions of endoscopic retrograde cholangiopancreatography;each of which took 30 min.No complications occurred during or after the procedure.The patient was fully recovered and discharged on day 11 of hospitalization.ML using a gastric bezoar basket is a safe and effective retrieval method in select cases,and is considered as an alternative nonoperative option for the management of difficult CBD stones.展开更多
AIM:To evaluate the usefulness of contrast-enhanced harmonic endoscopic ultrasound(CH-EUS)in differentiating between pancreatic adenocarcinomas and other pancreatic disease.METHODS:This retrospective cohort study eval...AIM:To evaluate the usefulness of contrast-enhanced harmonic endoscopic ultrasound(CH-EUS)in differentiating between pancreatic adenocarcinomas and other pancreatic disease.METHODS:This retrospective cohort study evaluated90 patients who were seen between November 2010and May 2013.All these patients had solid pancreatic masses that had a hypoechoic appearance on EUS.All patients underwent CH-EUS to evaluate this diagnostic method’s usefulness.The mass lesions observed on CH-EUS were classified into three categories based on their echo intensity:hypoenhanced,isoenhanced,and hyperenhanced lesions.We adjusted the sensitivity and the specificity of each category for detecting malignancies.We also estimated the accuracy of CH-EUS by comparing it to a pathological diagnosis.RESULTS:Of the 90 patients,62 had a pancreatic adenocarcinoma.Fifty-seven out of 62 pancreatic adenocarcinomas showed a hypoenhanced pattern on CHEUS.The sensitivity was 92%,the specificity 68%and the accuracy approximately 82%.The area under the curve of the receiver operating characteristic analysis for CH-EUS was 0.799.There is a significant association between the hypoenhanced pattern on CH-EUS and pancreatic duct adenocarcinoma(χ2=35.264,P<0.001).In pathological examinations,the number of specimens for EUS-fine needle aspiration(EUS-FNA)was considered insufficient for diagnosis in three patients,and in two patients,the results were reported to be negative for malignancy.Pancreatic masses in all five patients revealed a hypoenhanced pattern with CH-EUS.Three patients were diagnosed with pancreatic adenocarcinoma based on the pathology results of a biopsy,and the remaining two patients were clinically diagnosed with malignancy.CONCLUSION:CH-EUS is useful for distinguishing between pancreatic adenocarcinoma and other pancreatic disease.When a pancreatic mass shows a hypoenhanced pattern on CH-EUS but involves either insufficient samples or negative results with EUS-FNA,clinicians might consider performing another pathologic diagnosis on the basis of an EUS-FNA sample or a biopsy.展开更多
AIM: To determine the risk factors for gallstone-related biliary events.METHODS: This retrospective cohort study evaluated magnetic resonance cholangiopancreatography imagesfrom 141 symptomatic and 39 asymptomatic gal...AIM: To determine the risk factors for gallstone-related biliary events.METHODS: This retrospective cohort study evaluated magnetic resonance cholangiopancreatography imagesfrom 141 symptomatic and 39 asymptomatic gallstone patients who presented at a single tertiary hospital between January 2005 and December 2012.RESULTS: Logistic regression analysis showed significant differences between symptomatic and asymptomatic patients with gallstones in relation to the number of gallstones,the angle between the long axis of the gallbladder and the cystic duct,and the cystic duct diameter.Multivariate analysis showed that the number of gallstones(OR = 1.27,95%CI: 1.03-1.57; P = 0.026),the angle between the long axis of the gallbladder and the cystic duct(OR = 1.02,95%CI: 1.00-1.03; P = 0.015),and the diameter of the cystic duct(OR = 0.819,95%CI: 0.69-0.97; P = 0.018) were significantly associated with biliary events.The incidence of biliary events was significantly elevated in patients who had the presence of more than two gallstones,an angle of > 92° between the gallbladder and the cystic duct,and a cystic duct diameter < 6 mm.CONCLUSION: These findings will help guide the treatment of patients with asymptomatic gallstones.Clinicians should closely monitor patients with asymptomatic gallstones who exhibit these characteristics.展开更多
AIM: To examine surgical specimens of pancreas with either chronic pancreatitis or pancreatic cancer in order to study whether ductal hyperplasia and dysplasia in pancreas represent precursor lesions for pancreatic ca...AIM: To examine surgical specimens of pancreas with either chronic pancreatitis or pancreatic cancer in order to study whether ductal hyperplasia and dysplasia in pancreas represent precursor lesions for pancreatic cancer.METHODS: We examined expression of Ki-67, CEA,p53, and K-ras, in the surgical specimens of pancreas with adenocarcinomas (n = 11) and chronic pancreatitis (n = 12). Cellular proliferation was assessed by Ki-67proliferation index using the proliferation marker Ki-67.In specimens with pancreas cancer, we divided pancreas epithelium into normal (n=7), ductal hyperplasia (n=3), dysplasia (n=4), and cancerous lesion (n=11) after hematoxylin and eosin staining, Ki-67, and CEA immunohistochemical staining. In cases with chronic pancreatitis, the specimen was pathologically examined as in cases with pancreas cancer, and they were also determined as normal (n=10), ductal hyperplasia (n=4), or dysplasia (n= 5). p53 and K-ras expression were also studied by immunohistochemical staining.RESULTS: In pancreatic cancer, the Ki-67 index was 3.73±3.58 in normal site, 6.62±4.39 in ductalhyperplasia, 13.47±4.02 in dysplasia and 37.03±10.05in cancer tissue, respectively. Overall, p53 was positive in normal ducts, ductal hyperplasia, dysplasia, and carcinoma cells in 0 of 14 (0%), 0 of 7 (0%), 7 of 9 (78%),and 10 of 11 (91%), respectively, and K-ras was positive in 0 of 8 (0%), 1 of 3 (33%), 4 of 6 (67%), 4 of 5 (80%),respectively.CONCLUSION: Our results favorably support the hypothesis that ductal hyperplasia and dysplasia of the pancreas might be precursor lesions for pancreas cancer.Further evaluation of oncogenes by the molecular study is needed.展开更多
Dissemination of gastric cancer may usually occur by direct spread through the perigastric tissues to adjacent organ, lymphatic spread, and hematogenous spread. We report a rare case of gastric cancer with mucosal met...Dissemination of gastric cancer may usually occur by direct spread through the perigastric tissues to adjacent organ, lymphatic spread, and hematogenous spread. We report a rare case of gastric cancer with mucosal metastastic lesion on the upper esophagus that was diagnosed by endoscopy and endosonography. A biopsy of the esophageal mass was performed and the pathologic findings with immunohistochemical stain for Mucin-5AC are proved to be identical to that of gastric adenocarcinoma, suggesting metastasis from main lesion of the gastric cancer. The lesion could not be explained by lymphatic or hematogenous spread,and its metastasis mechanism is considered to be different from previous studies. We suggest that the gastroesophageal reflux of cancer cells could be one of the possible metastatic pathways for metastasis of esophagus from an adenocarcinoma of the stomach.展开更多
In endoscopic submucosal dissection(ESD),the narrow gastrointestinal space can cause difficulty in surgical interventions.Tissue ablation apparatuses with high-power CO_(2) lasers or Nd:YAG lasers have been developed ...In endoscopic submucosal dissection(ESD),the narrow gastrointestinal space can cause difficulty in surgical interventions.Tissue ablation apparatuses with high-power CO_(2) lasers or Nd:YAG lasers have been developed to facilitate endoscopic surgical procedures.We studied the interaction of 808-nm laser light with a porcine stomach tissue,with the aim of developing a therapeutic medical device that can remove lesions at the gastrointestinal wall by irradiating a near-infrared laser light incorporated in an endoscopic system.The perforation depths at the porcine fillet and the stomach tissues linearly increased in the range of 2–8mm in proportion to the laser energy density of 63.7–382 kJ/cm^(2).Despite the distinct structural and compositional di®erence,the variation of the perforation depth between the stomach and the fillet was not found at 808-nm wavelength in our measurement.We further studied the laser–tissue interaction by changing the concentration of the methyl blue solution used conventionally as a submucosal fluidic cushion(SFC)in ESD procedures.The temperature of the mucosal layer increased more rapidly at higher concentration of the methyl blue solution,because of enhanced light absorption at the SFC layer.The insertion of the SFC would protect the muscle layer from thermal damage.We confirmed that more effective laser treatment should be enabled by tuning the opto-thermal properties of the SFC.This study can contribute to the optimization of the driving parameters for laser incision techniques as an alternative to conventional surgical interventions.展开更多
文摘AIM:To investigate whether bile duct angulation and T-tube choledochostomy influence the recurrence of choledocholithiasis.METHODS:We conducted a retrospective study including 259 patients who underwent endoscopic sphincterotomy and cholecystectomy for choledocholithiasis between 2000 and 2007.The imaginary line was drawn along the center of the bile duct and each internal angle was measured at the two angulation sites ofthe bile duct respectively.The values of both angles were added together.We then tested our hypothesis by examining whether T-tube choledochostomy was performed and stone recurrence occurred by reviewing each subject's medical records.RESULTS:The overall recurrence rate was 9.3% (24 of 259 patients).The mean value of sums of angles in the recurrence group was 268.3°± 29.6°,while that in the non-recurrence group was 314.8°± 19.9° (P < 0.05).Recurrence rate of the T-tube group was 15.9% (17 of 107),while that of the non T-tube group was 4.6% (7 of 152) (P < 0.05).Mean value of sums of angles after T-tube drainage was 262.5°± 24.6° and that before T-tube drainage was 298.0°± 23.9° in 22 patients (P < 0.05).CONCLUSION:The bile duct angulation and T-tube choledochostomy may be risk factors of recurrence of bile duct stones.
文摘AIM: To evaluate clinical outcomes of patients that underwent surgery, transarterial embolization (TAE), or supportive care for spontaneously ruptured hepatocellular carcinoma (HCC). METHODS: A consecutive 54 patients who diagnosed as spontaneously ruptured HCC at our institution between 2003 and 2012 were retrospectively enrolled. HCC was diagnosed based on the diagnostic guidelines issued by the 2005 American Association for the Study of Liver Diseases. HCC rupture was defined as disruption of the peritumoral liver capsule with enhanced fluid collection in the perihepatic area adjacent to the HCC by dynamic liver computed tomography, and when abdominal paracentesis showed an ascitic red blood cell count of > 50000 mm 3 /mL in bloody fluid. RESULTS: Of the 54 patients, 6 (11.1%) underwent surgery, 25 (46.3%) TAE, and 23 (42.6%) supportive care. The 2-, 4and 6-mo cumulative survival rates at 2, 4 and 6 mo were significantly higher in the surgery (60%, 60% and 60%) or TAE (36%, 20% and 20%) groups than in the supportive care group (8.7%, 0% and 0%), respectively (each, P < 0.01), and tended to be higher in the surgical group than in the TAE group. Multivariate analysis showed that serum bilirubin (HR = 1.09, P < 0.01), creatinine (HR = 1.46, P = 0.04), and vasopressor requirement (HR = 2.37, P = 0.02) were significantly associated with post-treatment mortality, whereas surgery (HR = 0.41, P < 0.01), and TAE (HR = 0.13, P = 0.01) were inversely associated with posttreatment mortality. CONCLUSION: Post-treatment survival after surgery or TAE was found to be better than after supportive care, and surgery tended to provide better survival benefit than TAE.
文摘Duodenal perforation during endoscopic retrograde cholangiopancreatography(ERCP) is a rare complication,but it has a relatively high mortality risk.Early diagnosis and prompt management are key factors for the successful treatment of ERCP-related perforation.The management of perforation can initially be conservative in cases resulting from sphincterotomy or guide wire trauma.However,the current standard treatment for duodenal free wall perforation is surgical repair.Recently,several case reports of endoscopic closure techniques using endoclips,endoloops,or fully covered metal stents have been described.We describe four cases of iatrogenic duodenal bulb or lateral wall perforation caused by the scope tip that occurred during ERCP in tertiary referral centers.All the cases were simply managed by endoclips under transparent capassisted endoscopy.Based on the available evidence and our experience,endoscopic closure was a safe and feasible method even for duodenoscope-induced perforations.Our results suggest that endoscopists may be more willing to use this treatment.
基金Supported by Grant from Inha University Research
文摘Mechanical lithotripsy(ML) is usually considered as a standard treatment option for large bile duct stones.However,it is impossible to retrieve oversized stones because the conventional lithotripsy basket may not be able to grasp the stone.However,there is no established endoscopic extraction method for such giant stone removal.We describe a case of successful extraction of a 4-cm large stone using a gastric bezoar basket.A 78-year-old woman had suffered from upper abdominal pain for 20 d.Contrast-enhanced computed tomogram revealed a 4-cm single stone in the distal common bile duct(CBD).Endoscopic stone retraction was decided upon and endoscopic papillary balloon dilation was performed using a large balloon.An attempt to capture the stone using a standard lithotripsy basket failed due to the large stone size.Subsequently,we used a gastric bezoar basket to successfully capturethe stone.The stone was fragmented into small pieces and extracted.The stone was completely removed after two sessions of endoscopic retrograde cholangiopancreatography;each of which took 30 min.No complications occurred during or after the procedure.The patient was fully recovered and discharged on day 11 of hospitalization.ML using a gastric bezoar basket is a safe and effective retrieval method in select cases,and is considered as an alternative nonoperative option for the management of difficult CBD stones.
文摘AIM:To evaluate the usefulness of contrast-enhanced harmonic endoscopic ultrasound(CH-EUS)in differentiating between pancreatic adenocarcinomas and other pancreatic disease.METHODS:This retrospective cohort study evaluated90 patients who were seen between November 2010and May 2013.All these patients had solid pancreatic masses that had a hypoechoic appearance on EUS.All patients underwent CH-EUS to evaluate this diagnostic method’s usefulness.The mass lesions observed on CH-EUS were classified into three categories based on their echo intensity:hypoenhanced,isoenhanced,and hyperenhanced lesions.We adjusted the sensitivity and the specificity of each category for detecting malignancies.We also estimated the accuracy of CH-EUS by comparing it to a pathological diagnosis.RESULTS:Of the 90 patients,62 had a pancreatic adenocarcinoma.Fifty-seven out of 62 pancreatic adenocarcinomas showed a hypoenhanced pattern on CHEUS.The sensitivity was 92%,the specificity 68%and the accuracy approximately 82%.The area under the curve of the receiver operating characteristic analysis for CH-EUS was 0.799.There is a significant association between the hypoenhanced pattern on CH-EUS and pancreatic duct adenocarcinoma(χ2=35.264,P<0.001).In pathological examinations,the number of specimens for EUS-fine needle aspiration(EUS-FNA)was considered insufficient for diagnosis in three patients,and in two patients,the results were reported to be negative for malignancy.Pancreatic masses in all five patients revealed a hypoenhanced pattern with CH-EUS.Three patients were diagnosed with pancreatic adenocarcinoma based on the pathology results of a biopsy,and the remaining two patients were clinically diagnosed with malignancy.CONCLUSION:CH-EUS is useful for distinguishing between pancreatic adenocarcinoma and other pancreatic disease.When a pancreatic mass shows a hypoenhanced pattern on CH-EUS but involves either insufficient samples or negative results with EUS-FNA,clinicians might consider performing another pathologic diagnosis on the basis of an EUS-FNA sample or a biopsy.
基金Supported by A research grant from Inha University
文摘AIM: To determine the risk factors for gallstone-related biliary events.METHODS: This retrospective cohort study evaluated magnetic resonance cholangiopancreatography imagesfrom 141 symptomatic and 39 asymptomatic gallstone patients who presented at a single tertiary hospital between January 2005 and December 2012.RESULTS: Logistic regression analysis showed significant differences between symptomatic and asymptomatic patients with gallstones in relation to the number of gallstones,the angle between the long axis of the gallbladder and the cystic duct,and the cystic duct diameter.Multivariate analysis showed that the number of gallstones(OR = 1.27,95%CI: 1.03-1.57; P = 0.026),the angle between the long axis of the gallbladder and the cystic duct(OR = 1.02,95%CI: 1.00-1.03; P = 0.015),and the diameter of the cystic duct(OR = 0.819,95%CI: 0.69-0.97; P = 0.018) were significantly associated with biliary events.The incidence of biliary events was significantly elevated in patients who had the presence of more than two gallstones,an angle of > 92° between the gallbladder and the cystic duct,and a cystic duct diameter < 6 mm.CONCLUSION: These findings will help guide the treatment of patients with asymptomatic gallstones.Clinicians should closely monitor patients with asymptomatic gallstones who exhibit these characteristics.
基金Supported by the Inha University Research Grant 2005
文摘AIM: To examine surgical specimens of pancreas with either chronic pancreatitis or pancreatic cancer in order to study whether ductal hyperplasia and dysplasia in pancreas represent precursor lesions for pancreatic cancer.METHODS: We examined expression of Ki-67, CEA,p53, and K-ras, in the surgical specimens of pancreas with adenocarcinomas (n = 11) and chronic pancreatitis (n = 12). Cellular proliferation was assessed by Ki-67proliferation index using the proliferation marker Ki-67.In specimens with pancreas cancer, we divided pancreas epithelium into normal (n=7), ductal hyperplasia (n=3), dysplasia (n=4), and cancerous lesion (n=11) after hematoxylin and eosin staining, Ki-67, and CEA immunohistochemical staining. In cases with chronic pancreatitis, the specimen was pathologically examined as in cases with pancreas cancer, and they were also determined as normal (n=10), ductal hyperplasia (n=4), or dysplasia (n= 5). p53 and K-ras expression were also studied by immunohistochemical staining.RESULTS: In pancreatic cancer, the Ki-67 index was 3.73±3.58 in normal site, 6.62±4.39 in ductalhyperplasia, 13.47±4.02 in dysplasia and 37.03±10.05in cancer tissue, respectively. Overall, p53 was positive in normal ducts, ductal hyperplasia, dysplasia, and carcinoma cells in 0 of 14 (0%), 0 of 7 (0%), 7 of 9 (78%),and 10 of 11 (91%), respectively, and K-ras was positive in 0 of 8 (0%), 1 of 3 (33%), 4 of 6 (67%), 4 of 5 (80%),respectively.CONCLUSION: Our results favorably support the hypothesis that ductal hyperplasia and dysplasia of the pancreas might be precursor lesions for pancreas cancer.Further evaluation of oncogenes by the molecular study is needed.
文摘Dissemination of gastric cancer may usually occur by direct spread through the perigastric tissues to adjacent organ, lymphatic spread, and hematogenous spread. We report a rare case of gastric cancer with mucosal metastastic lesion on the upper esophagus that was diagnosed by endoscopy and endosonography. A biopsy of the esophageal mass was performed and the pathologic findings with immunohistochemical stain for Mucin-5AC are proved to be identical to that of gastric adenocarcinoma, suggesting metastasis from main lesion of the gastric cancer. The lesion could not be explained by lymphatic or hematogenous spread,and its metastasis mechanism is considered to be different from previous studies. We suggest that the gastroesophageal reflux of cancer cells could be one of the possible metastatic pathways for metastasis of esophagus from an adenocarcinoma of the stomach.
基金This study was supported by grants from the Industrial Core Technology Development Program (10047904)the Industrial Strategic Technology Development Program (10049743) of the Korea Evaluation Institute of Industrial Technology(KEIT)the Human Resources Development Program (20134010200580)of the Korea Institute of Energy Technology Evaluation and Planning(KETEP)funded by the Ministry of Trade,Industry and Energy,Republic of Korea.
文摘In endoscopic submucosal dissection(ESD),the narrow gastrointestinal space can cause difficulty in surgical interventions.Tissue ablation apparatuses with high-power CO_(2) lasers or Nd:YAG lasers have been developed to facilitate endoscopic surgical procedures.We studied the interaction of 808-nm laser light with a porcine stomach tissue,with the aim of developing a therapeutic medical device that can remove lesions at the gastrointestinal wall by irradiating a near-infrared laser light incorporated in an endoscopic system.The perforation depths at the porcine fillet and the stomach tissues linearly increased in the range of 2–8mm in proportion to the laser energy density of 63.7–382 kJ/cm^(2).Despite the distinct structural and compositional di®erence,the variation of the perforation depth between the stomach and the fillet was not found at 808-nm wavelength in our measurement.We further studied the laser–tissue interaction by changing the concentration of the methyl blue solution used conventionally as a submucosal fluidic cushion(SFC)in ESD procedures.The temperature of the mucosal layer increased more rapidly at higher concentration of the methyl blue solution,because of enhanced light absorption at the SFC layer.The insertion of the SFC would protect the muscle layer from thermal damage.We confirmed that more effective laser treatment should be enabled by tuning the opto-thermal properties of the SFC.This study can contribute to the optimization of the driving parameters for laser incision techniques as an alternative to conventional surgical interventions.