Zita Hornok’s research while affiliated with Magyarországi Református Egyház Bethesda Gyermekkórháza and other places

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.

Simulation-based training (SBT) has a significant role in training in complex procedure like laparoscopic pyeloplasty. We propose a new training model for laparoscopic pyeloplasty which has been compared to other models. Trainees (n = 22) evaluated our balloon model (BM) and three other models -glove finger model (GFM), chicken thigh model (ChTM) and chicken crop model (ChCrM)- subjectively, based on a 5-point Likert scale. The face validity mean score of our BM model was 3.58 ± 0.69. Our novel model can be a cost-effective, hygienic, and easy-access alternative to other laparoscopic pyeloplasty models.

Background We designed a new Esophageal Magnetic Anastomosis Device (EMAD) for thoracoscopic repair of esophageal atresia (EA) with tracheoesophageal fistula (TEF) without the need of handheld suturing or additional gastrostomy. Methods Synthetic EA-TEF model: Spherical and tubular shaped rubber balloons and a term infant sized plastic doll were used. Medical students (n=10) and surgical trainees (n=10) were asked to perform thoracoscopic repair of an „EA” with a hand sutured anastomosis (HA) and with the EMAD. Euthanized animal model: The esophagus in 5 piglets (3-4 kg) was dissected and a thoracoscopic esophageal magnetic anastomosis (EMA) was performed. Bursting pressure (BP) and pulling force (PF): HA and EMA were created on ex vivo New Zealand white rabbit (2.5-3 kg) esophagi (n=25 in each test series). BP and PF were measured and compared against each other. Results Medical students were unable to complete HA, but were successful with the EMAD in 11.1±2.78 min. Surgical trainees completed EMA in 4.6±2.06 min vs. HA 30.8±4.29 min (p<0.001). The BP following a HA (14.1±3.32 cmH2O) was close to the physiological intraluminal pressure reported in a neonatal esophagus (around 20 cmH2O), whereas the BP with the EMAD was extremely high (>90 cmH2O) (p<0.001). The PF of an EMA (1.8±0.30 N) was closer to the safety limits of anastomotic tension reported in the literature (i.e. 0.75 N) compared with the HA (3.6±0.43 N) (p<0.0001). Conclusion The EMAD could simplify, shorten, and potentially improve the outcome of thoracoscopic repair for EA with TEF in the future. A high BS and a relative low PF following EMAD application may lower the risk of postoperative complications such as esophageal leakage and stricture formation.