Basic Science: Stones
Moderated Poster Session
MP2-10 - Histopathological evaluation of inflammation in the ureteral wall after UAS usage during RIRS
Thursday, September 20
4:00 PM - 6:00 PM
Location: Room 242B
Lillebaelt Hospital, Urology, Vejle, Denmark
Introduction & Objective : Pro-inflammatory mediators have been shown to be significantly upregulated in ureteral wall tissue after retrograde intrarenal surgery (RIRS) using ureteral access sheaths (UAS). The objective of this study was to evaluate the histopathological evidence of inflammation in the ureteral wall after RIRS using UAS.
Methods : Ureteral access sheaths (UAS) sized 13/15 Fr. were inserted bilaterally in the ureters of 22 laboratory pigs (55kg). On one side the UAS was removed after 2 minutes followed by 2 hours of reperfusion and on the other side it was left in situ for 2 hours. After removal of the 2-hour UAS, both ureters were excised in vivo between the uretero-pelvic junction and the uretero-vesical junction. Embedded in paraffin 4 µm thick sections were step sectioned at 250-300 µm intervals and haematoxylin and eosin (HE) stained. An experienced pathologist performed histopathological scoring of acute neutrophilic inflammation in the ureteral wall. 0 = no inflammation; 1 = mild inflammation; 2 = severe inflammation.
There were 21 ureters in the 2-minute group and 22 in the 2-hour group. In total 3276 sections were evaluated. 14 sections were not evaluated due to artifacts. No ureters were without inflammation. Only 109 sections (3.3%) were with no sign of inflammation. 2269 sections (69.3%) showed mild inflammation and 878 sections (26.8%) showed severe inflammation.
In the 2-minute group 65 sections showed no sign of inflammation, 1103 showed mild inflammation and 479 showed severe inflammation. In the 2-hour group 44 sections showed no sign of inflammation, 1166 showed mild inflammation and 405 showed severe inflammation.
Comparison of short versus long-term UAS treatment yielded no statistically significant difference, but there was a trend towards a higher degree of inflammation after short-term treatment (1.25 (CI: 1.23-1.28) vs. 1.23 (CI: 1.21-1.25)), (p= 0.07).
Conclusions : Mild to severe acute neutrophilic inflammation was evident in 96% of the ureteral wall tissue after treatment with UAS. There was no significant difference between short and long treatment duration.