Impact of sampling side of peritoneal biopsies on peritoneal thickness and histopathological diagnosis—A quantitative histological study in body donors

BackgroundCurrently several registries investigate the structure of the peritoneum in response to uremia and peritoneal dialysis. Those registries using a single peritoneal sample obtained during surgical procedures involving the abdomen. There are no data to support the assumption that a single random sample from the peritoneum is representative of other regions of the peritoneum. The aim of our study was to investigate the potential effect of the sampling site of the parietal peritoneum on peritoneal thickness.MethodsFor the study 19 body donors (8 F /11 M), medium IQR age 82 77-88 years were investigated. Peritoneal samples were obtained from five different, predefined sites of the peritoneal cavity involving visceral and parietal peritoneum. Routine histology was performed at the Department of Nephropathology Erlangen.ResultsA total number 95 samples from 19 body donors were analyzed. There was a wide intraindividual variation of the peritoneal thickness. In the entire cohort, median IQR maximum thickness of the peritoneum did not significantly differ between the four samples of the parietal peritoneum 130 60-170 µm | 130 70-200 µm | | 140 110-240 µm | 140 110-150 µm. Median IQR maximum thickness of the visceral peritoneum was however thinner 90 60-130 µm than all parietal peritoneal samples (p = .01). Based on the intraindividual variation in our cohort we calculated a cohort of 24.7 patients needed to detect longitudinal changes of peritoneal thickness at medium effect size with a power of 0.8 at p < .05.ConclusionsThe visceral peritoneum differs in thickness form the parietal peritoneum. The sample site of the parietal peritoneum has no effect on the peritoneal thickness. The large intraindividual variation in the peritoneal thickness require large cohorts to detect longitudinal change of the peritoneum. Despite the limitation that it remains uncertain if these results from body donors can be assumed to be true in ex-vivo biopsies, it seems prudent to state that interpreting sequential peritoneal biopsies in single patients or small case series should be interpreted with caution.