INFLUENCE OF GASTROESOPHAGEAL REFLUX ON SURGICAL SUTURE MATERIALS USED FOR ESOPHAGOTOMY IN PIGS - EX VIVO STUDY

Proteklih desetljeća gastroezofagealna refluksna bolest (GERB) sve se češće javlja u populaciji naročito u zapadnim zemljama. Prema definiciji GERB predstavlja stanje u kojem želučani refluksni sadržaj dovodi do razvoja simptoma ili komplikacija. Klinička slika uključuje različite simptome, od žgaravice i regurgitacije do razvoja ozbiljnih komplikacija poput erozivnog ezofagitisa i adenokarcinoma. Niske vrijednosti pH kao i prisustvo bakterija mogu utjecati na proces razgradnje kirurških šivaćih materijala, što može dovesti do ozbiljnih posljedica u slučajevima rekonstrukcije ozljede jednjaka. Cilj ovog istraživanja bio je odrediti učinak kiselih uvjeta i pepsina te sukralfata na čvrstoću šava ezofagotomije. U ovom istraživanju 54 uzorka jednjaka svinja podijeljena su u 3 grupe prema uvjetima izloženosti lumena jednjaka. Svaka grupa podijeljena je u 3 podgrupe ovisno o vrsti korištenog šivaćeg materijala. Na svim uzorcima učinjen je rez ezofagotomije u duljini od 4 cm smještenom 5 cm od spoja jednjaka sa želucem. Rekonstrukcija je učinjena kirurškim šivaćim materijalom ovisno o pripadnosti pojedinoj podgrupi koristeći Biosyn, PDS II i V-LocTM 90 debljine 4-0 i jednakih igala. Nakon rekonstrukcije mjerio se intraluminalni tlak pri propuštanju za svaki pojedini uzorak. Za mjerenje intraluminalnog tlaka korištene su 2 različite tehnike. Kod standardne tehnike intraluminalni tlak pri propuštanju mjeren je pomoću komorice za mjerenje arterijskog tlaka i ubrizgavanja otopine metilenskog modrila. Kod novog modela tehnike mjerenja jednjaci su upuhivani pomoću anesteziološkog uređaja koristeći cikluse višeg tlaka kako bi se oponašala peristaltika jednjaka. U kontrolnoj skupini intraluminalni tlak pri propuštanju mjeren je pomoću obje tehnike dok se u ostalim skupinama on mjerio samo novim modelom. U skupinama GERB i GERB+sukralfat rekonstrukcija je učinjena sa šivaćim materijalima koji su 5 dana bili izloženi djelovanju pepsina i kiselih uvjeta. Nakon rekonstrukcije ezofagotomije u skupini GERB lumen jednjaka izložen je kiselim uvjetima u trajanju 60 minuta te je potom testiran intraluminalni tlak pri propuštanju. U skupini GERB+sukralfat tekući oblik sukralfata apliciran je u lumen jednjaka u trajanju 5 minuta nakon čega se izložio kiselim uvjetima. Nakon testiranja intraluminalnog tlaka 6 uzoraka iz svake skupine histološki je pregledano kako bi se uočila oštećenja sluznice. Vlačna čvrstoća i maksimalno produljenje niti određeni su za korištene šivaće materijale kontrolne skupine i onih izloženih kiselim uvjetima i pepsinu. Rezultati istraživanja pokazuju da je tlak izmjeren novom metodom značajno veći od tlaka mjerenog standardnom metodom, te su oni u pozitivnoj korelaciji. Uspoređujući vrijednosti intraluminalnog tlaka mjerenog novom metodom u kontrolnoj skupini značajno više uzoraka podskupine V-Loc je propuštalo pri ciklusu koji odgovara unosu krutog sadržaja. Vrijednosti intraluminalnog talka u skupini GERB+sukralfat podskupini V-Loc značajno su više od ostalih podskupina. Histopatološkom pretragom opsežnija oštećenja sluznice jednjaka uočena su u skupinama GERB i GERB+sukralfat. Od korištenih šivaćih materijala V-LocTM 90 posjeduje značajno nižu vlačnu čvrstoću, te ima manju elastičnost od ostalih materijala. Kiseli uvjeti povećali su maksimalno produljenje niti PDS II dok su se kod V-LocTM 90 vrijednosti dodatno smanjile. gastroezofagealna refluksna bolest, jednjak, ex vivo studija,Over the last two decades, gastroesophageal reflux disease (GERD) has increasing prevalence in human population, especially in western countries. By the definition GERD is a condition in which the reflux of gastric contentment into esophagus is causing symptoms or complications. Clinical presentation includes variety of symptoms, ranging from typical ones such as heartburn and regurgitation, or coughing and sleep disturbances, to severe complications such as erosive esophagitis, Barrett´s esophagus and esophageal adenocarcinoma. Surgical procedures on esophagus are performed in different pathological conditions and one of them is esophageal perforations. Primary reconstruction and total esophagectomy are mostly used techniques for surgical management of esophageal perforation. Appearance of wound dehiscence as a complication of esophagotomy used for primary reconstruction of esophageal reconstruction can range from 25-50%. Presence of body fluids such as urine, bacteria or pH values can influence on resorption of used suture materials. Increased suture degradation therefore can have fatale consequence. Aim of this study was to determine the effect of pepsin, HCl and sucralfate on strength of esophagotomy reconstruction line and to compare two different methods for intraluminal pressure mesurement. We presumed that application of sucralfate for 5 minutes can reduce influence of pepsin and HCl solution on esophagotomy suture line. Also, our presumption was that mucosal exposure to 1% solution of pepsin and HCl pH 2 can simulate GERD and reduce leakage pressure of esophagotomy suture line. In this study 54 porcine esophagus were tested and divided in 3 groups based on conditions in which esophagotomy suture were exposed (control group, GERD, GERD + sucralfate). Each group contained 3 subgroups based on suture material used for esophagotomy closure (Biosyn, PDS II and V-Loc). Esophageal tissue samples were obtained from fresh slaughtered pigs of both sexes weighting from 100 to 120 kg. During testing only the caudal parts of esophagus were used in length of 15 cm. The longitudinal 4 cm long esophagotomy incision were performed 5 cm cranial to lower esophageal sphincter throughout all layers. Esophagotomy closure were performed based on subgroups classification with one of the suture materials (Biosyn, PDS II and V-LocTM 90) size 4-0 using simple continuous pattern including all esophageal layers. During reconstruction each suture bite was placed at intervals of 2-3 mm and 3 mm from the cut edge of the incision. In Biosyn and PDS II subgroup sutures were tied with 2 square knots placed on each side of incision line, and in V-Loc subgroups suture was secured by pulling a suture and needle through fixed loop in the beginning of closure technique and cutting the strand 0,5 – 1 cm after the last tissue passing. For every suture material used for esophagotomy reconstruction needle size and shape was identical, half circle with rounded tip and body and diameter of 17 mm. After performing esophagotomy, compressed esophageal diameter were measured in the middle part of incision line and recorded. The 2 opposite passing’s through the tissue were named as trans-stabs and their number was recorded. After the reconstruction of esophagotomy, the intraluminal pressure was tested for each sample. In the standard technique of intraluminal pressure testing both ends of esophagus were closed with tissue clamps. On the cranial portion of esophagus, the methylene blue dye diluted with saline was injected with infusion pump connected on catheter and hypodermic needle at rate 100 ml/h. Intraluminal pressure was measured by needle inserted in caudal part of esophagus connected to blood pressure transducer and patient monitor. Moment when leakage of blue coloured solution on the suture line was observed the intraluminal measured pressure was recorded and named as pressure 1. With the new model of intraluminal pressure testing, endotracheal tube (inner diameter 5,5-7mm) was inserted at the cranial part of esophagus and fixed with a band. Endotracheal tube was connected to anaesthesia ventilation machine to imitate esophageal peristalsis. Caudal part of the esophagus was occluded with tissue clamp. On the anaesthesia machine, positive end expiratory pressure (PEEP) was set at value of 4 cm H2O and testing started at peak inspiratory pressure (PIP) of 10 cm H2O. Air flow was set for 1 L/min. Test sample was then submerged into water to detect air bubbles present at leakage. During first minute of ventilation esophagus was inflated 12 times with inspiration expiration ratio 1: 1 set as cycle 1 which represented liquid bolus. During the second minute esophagus was inflated 4 times set as cycle 2 which represented solid bolus. After 2 minutes of ventilation with both cycles PIP was gradually increased by 2 cm H2O using cycles 1 and 2 until the leakage occurred. When the presence of air bubbles in water was noted, the PIP used for ventilation was recorded and named pressure 2. Data for cycle type and location of leakage was also recorded. In control group intraluminal pressure was tested with standard and new technique while in other groups the intraluminal pressure was tested only with new technique. Dilatation of esophagus was categorised if the diameter of esophagus at leakage was > 30 mm. Values of intraluminal pressure 1 and 2 > 30 mmHg recorded during experiment were named insufficient peristalsis. In the control group sutures used for esophagotomy closure or esophageal lumen weren’t exposed to abnormal conditions while in groups GERD and GERD + sucralfate the reconstruction of esophagotomy were done by suture material held 5 days in acid conditions. Suture acid conditions were imitated by 5 days long immersion of suture material in acidic solution of 1% pepsin with HCl to pH 2 inside of thermostat on 37ºC at 5 % CO2. In the GERD group after the reconstruction of esophagotomy with suture materials held for 5 days in acidic conditions the lumen of esophagus was infused with solution of 1% pepsin in sterile solution acidified with HCl at pH 2. The acidic solution was infused inside of esophageal lumen with perfusion pump at rate 1 ml/min during 1 h with catheter placed on cranial part of esophagus. After infusion of acidic solution esophagus were rinsed with saline at rate 200 ml/h for 2 minutes and then submersed in water and the intraluminal pressure was tested with new method for testing. For testing the protective influence of sucralfate on esophageal mucosa in the group GERB + sucralfate 1 g of liquid form of sucralfate was applied with catheter and syringe inside of esophageal lumen after the reconstruction with suture material held in acidic conditions for 5 days. After 5 minutes of contact time for sucralfate, the esophageal lumen was treated with pepsin and HCl solution in the same manner as the control group. From all groups 6 samples were taken to histological examination 24 h after the intraluminal pressure testing. After obtaining the esophageal samples they were fixed in 10 % buffered formalin solution for 24 hours. Microscopic samples were dyed in hematoxilin-eozin method and observed under the 10 and 20 X magnification. Histological changes detected in mucosal layer were classified in 4 degrees based by extent and depth of the mucosal damage in cross section. Tensile strength and maximal elongation of samples for 3 different suture materials (Biosyn, PDS II and V-LocTM 90) were tested in Laboratory for experimental mechanic on testing machine with initial speed 20 mm/min and predetermined load of 1 N. Also, the same testing was performed on suture materials incubated in acidic conditions described earlier. In this study results showed that values for pressure 1 and pressure 2 are in statistically significant positive corelation. Values for pressure 1 were significantly lower for 21.27 mmHg than values for pressure 2 (p<0.001). In subgroup V-Loc delta for pressure values were significantly higher than ones measured in other groups (p=0.02). In control group categorisation for ineffective esophageal peristalsis showed significantly higher number of ineffective peristalses measured with standard technique then with the new technique (p<0.01). Analysis for pressure 2 showed that only in control group subgroup V-Loc significantly more samples showed leakage during testing for solid bolus (p=0.04). In group GERB+sucralfate subgroup V-Loc all the samples showed leakage categorised as functional peristalsis (p=0.02). The same subgroup had significantly higher measured pressure 2 values the other subgroups (p=0.035). Values for delta and ratio of oesophageal diameter before and after testing depended significantly among groups (p