Abstract
Objective The pyeloureteral anastomosis remains the most challenging part of pyeloplasty. A
purpose-built anastomotic device could simplify this step and potentially improve
outcomes. The concept of a pyeloureteral magnetic anastomosis device (PUMA) was proven
in minipigs, but only in short term. Our aim was to test the PUMA in domestic pigs
and achieve a prolonged follow-up period.
Methods Five female domestic pigs underwent laparoscopy and ligation of the left ureter.
Four weeks later, laparoscopic implantation of the PUMA was planned. Removal of the
device and a retrograde contrast study were scheduled after another 4 weeks. The experiment
was terminated when the animals could no longer be properly cared for due to their
weight.
Results Due to unexpected smaller ureteric diameters, a modified PUMA could only be successfully
inserted in pig number 3 (49 kg). Four weeks later, the device was found to be dislocated,
but the anastomosis remained patent. After modifying the study protocol, the PUMA
was successfully implanted in pigs number 4 (96 kg) and 5 (68 kg) 8 weeks after ureteric
ligation. Pig 4 developed malignant hyperthermia and died. In pig 5, the magnets were
removed 4 weeks later. After an additional 8 weeks, the animal reached 135 kg and
was terminated. The anastomosis remained patent and preserved its diameter.
Conclusion Despite limitations, our study successfully demonstrated that the PUMA can achieve
a patent ureteric anastomosis in domestic pigs. This suggests a potential for minimally
invasive ureteric anastomosis in clinical settings. Further research is needed to
optimize the technique and validate its effectiveness in humans.
Keywords
laparoscopy - magnamosis - surgical innovation - PUMA device - pyeloplasty
