Postoperative Adhesion Formation after Peritoneoscopy with Liver Biopsy in a Survival Porcine Model: Laparotomic Vs Laparoscopic Vs NOTES® Transgastric Approach

Background: Adhesions are an almost inevitable consequence of laparotomy and laparoscopy, although laparoscopic surgery produces fewer adhesions than laparotomy. It is suggested that minimizing the invasiveness of the operative technique by using NOTES™ may reduce adhesion formation. Objective: The aim of the study was to compare the rate of the adhesion formation after peritoneoscopy with liver biopsy by laparotomy, laparoscopy and transgastric NOTES™. DESIGN: Experimental comparative survival study. Setting: Research facility of the Johns Hopkins University School of Medicine. Patients: 18 female pigs that weighed 35-40 kg were used. Interventions and Methods: Peritoneoscopy with liver biopsy was randomized to 1 of 3 groups: control, laparotomy (n=6); laparoscopy (n=6), NOTES™ transgastric (n=6). Pre-operative, operative, and post-operative care was standardized. The Hopkins Adhesion Formation score method was used to assess adhesion formation. The following parameters were evaluated 1) extent - (the abdomen was divided into 4 quadrants - left upper quadrant, right upper quadrant, left lower quadrant and right lower quadrant; number of involved abdominal quadrants was documented); 2) frequency (number of bands); 3) size/width (total size/width of all adhesions was measured and summed total for every animal); 4) organ involvement (number of organs involved); 5) density of the adhesions; 6) dissectibility of the adhesions; and 7) vascularization. MAIN OUTCOME MEASUREMENTS: (1) Survival and complication rates (2) Necropsy (Day 14) (3) Assessment of adhesion formation rate using the Hopkins Adhesion Formation Score; (4) Differences between the groups by one-way analysis of variance (ANOVA) followed by a Tukey post-test analysis (5) Pearson product moment correlation coefficient (r-value) between the adhesion scores of two investigators. Results: There was no mortality in any study group. 100% of pigs in laparotomy group, 33.3% in laparoscopy group had adhesions compare to 16.7% in transgasric NOTES™ group. One adhesion band was documented in Group III (transgastric NOTES™), 4 adhesion bands in Group II (laparoscopy) and 17 in Group I (laparotomy). The mean adhesion formation scores of laparotomy and laparoscopy were 2.4 and 0.8 compared with 0.17 in the transgastric NOTES™ (P< 0.001). The Correlation coefficient between the adhesion scores of two investigators was r = 0.99 (p < 0.001, 95% CI). Limitations: Low number of study animals. Conclusions: Rate and severity of adhesion formation was lower in the transgastric NOTES™ group compared to laparoscopy and laparotomy, when peritoneoscopy with liver biopsy was performed.