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.
