Generally % 10 formol solution is use to do fixation to all specimens after the surgical operations for the pathological evaluation. It is known that the formol solution cause amount of shrinkage in the tissue volume . This effect of formol solution had researched in colon,breast and prostate previously. But there is no evidence about stomach. The purpose of this research is that find out the formol effect to the gastric tissue and detect the shrinkage percent.

All gastric specimens which removed after Laparoscopic Sleeve Gastrectomy will open from the major curvature and spread down to the table.in operating room..3 cm x 3 cm three tissue samples will collect from the specific locations. These three locations are ; fundus( 1 cm from the top of staple line) , corpus (middle of the major curvature , antrum ( 1 cm far from the bottom of staple line ). All these points 5 mm far from the major curvature. 6 samples will prepare totally. 2 samples for each location ; one mucosa and one all layer of gastric wall for each location .These 3 points will examine about wall thickness(mucosa- submucosa-muscularis propria -serosa ) After saving the measurements in operating room;the gastric specimen will deliver to a pathologist to put the specimen into the % 10 formol solution. After 24 hours ;pathologist will save all of new measurements same in operating room. The measurements of sample are ;height , length , width . After the completion of the measurements the investigator will compare the results found in operating room in fresh specimen with pathologist 's results after formol. After that the investigator will be able to decide the shrinkage of gastric tissue in % 10 formol solution.

Inclusion Criteria:

• Patients older than 18 years old who will undergo to Laparoscopic Sleeve Gastrectomy

Exclusion Criteria:

• Patients who has to undergo another bariatric surgery type peroperatively
• Deformation of gastric specimen while removing from the abdomen