The effects of ureteral mobilization and transection on ureteral oxygenation

To determine the impact of ureteral transection with and without prior ureteral mobilization on ureteral oxygen partial pressure (p(u)O(2)).

Sixteen pigs underwent general anesthesia with laparoscopic transperitoneal access to the right ureter. With no dissection and minimal manipulation, a tissue oxygen probe (Licox, Kiel, Germany) was introduced via a trocar and inserted into the ureter. The probes were placed at the ureteropelvic junction (UPJ, n = 8) and ureterovesical junction (UVJ, n = 8). Baseline p(u)O(2) was measured. Subsequently, half of the animals at each level (n = 4) underwent complete ureteral transection proximal to UPJ probes and distal to UVJ probes with or without prior mobilization. p(u)O(2) levels were measured after ureteral mobilization and transection.

Of the ureters transected at the UPJ without mobilization, the mean p(u)O(2) level declined by 13 mm Hg relative to baseline (P = 0.07). The baseline UPJ p(u)O(2) level declined by 5 mm Hg after ureteral mobilization alone and subsequently by 31 mm Hg after transection (P <0.01). Of the ureters transected at the UVJ without mobilization, the p(u)O(2) level decreased by 4 mm Hg relative to baseline (P = 0.08). The baseline UVJ p(u)O(2) level decreased by 15 mm Hg after ureteral mobilization alone and subsequently by 39 mm Hg after transection (P <0.01). At both the UPJ and UVJ, the transected-only p(u)O(2) level was statistically higher than the mobilized and transected level (P = 0.03, respectively).

During ureteral surgery, mobilization alone exposes the distal ureter to more ischemia than the proximal ureter, and efforts to minimize ureteral mobilization when transection is necessary are crucial in maintaining tissue oxygenation.